Ibrahim Tekin - Academia.edu (original) (raw)

Papers by Ibrahim Tekin

Research paper thumbnail of Diamond semiconductor technology for RF device applications

Solid-state Electronics, 2005

This paper presents a comprehensive review of diamond electronics from the RF perspective. Our ai... more This paper presents a comprehensive review of diamond electronics from the RF perspective. Our aim was to find and present the potential, limitations and current status of diamond semiconductor devices as well as to investigate its suitability for RF device applications. While doing this, we briefly analysed the physics and chemistry of CVD diamond process for a better understanding of the reasons for the technological challenges of diamond material. This leads to Figure of Merit definitions which forms the basis for a technology choice in an RF device/system (such as transceiver or receiver) structure. Based on our literature survey, we concluded that, despite the technological challenges and few mentioned examples, diamond can seriously be considered as a base material for RF electronics, especially RF power circuits, where the important parameters are high speed, high power density, efficient thermal management and low signal loss in high power/frequencies. Simulation and experimental results are highly regarded for the surface acoustic wave (SAW) and field emission (FE) devices which already occupies space in the RF market and are likely to replace their conventional counterparts. Field effect transistors (FETs) are the most promising active devices and extremely high power densities are extracted (up to 30 W/mm). By the surface channel FET approach 81 GHz operation is developed. Bipolar devices are also promising if the deep doping problem can be solved for operation at room temperature. Pressure, thermal, chemical and acceleration sensors have already been demonstrated using micromachining/MEMS approach, but need more experimental results to better exploit thermal, physical/chemical and electronic properties of diamond.

Research paper thumbnail of A fully integrated multiband frequency synthesizer for WLAN and WiMAX applications

This paper presents a fractional N frequency synthesizer which covers WLAN and WiMAX frequencies ... more This paper presents a fractional N frequency synthesizer which covers WLAN and WiMAX frequencies on a single chip. The synthesizer is fully integrated in 0.35μm BiCMOS AMS technology except crystal oscillator. The synthesizer operates at four frequency bands (3.101-3.352GHz, 3.379-3.727GHz, 3.7-4.2GHz, 4.5-5.321GHz) to provide the specifications of 802.16 and 802.11 a/b/g/y. A single on-chip LC -Gm based VCO is implemented as the core of this synthesizer. Different frequency bands are selected via capacitance switching and fine tuning is done using varactor for each of these bands. A bandgap reference circuit is implemented inside of this charge pump block to generate temperature and power supply independent reference currents. Simulated settling time is around 10μsec. Total power consumption is measured to be 118.6mW without pad driving output buffers from a 3.3V supply. The phase noise of the oscillator is lower than -116.4dbc/Hz for all bands. The circuit occupies 2.784 mm 2 on Si substrate, including DC, Digital and RF pads.

Research paper thumbnail of A matching circuit tuned, multi-band (WLAN and WiMAX), Class — a power amplifier using 0.25μm-SiGe HBT technology

In this work, a MOS based output matching network is designed and fabricated using IHP (innovatio... more In this work, a MOS based output matching network is designed and fabricated using IHP (innovations for high performance), 0.25 mum-SiGe HBT process and measured which can give 4 different impedance values. Also, a multi-band, Class-A, power amplifier (PA) has been designed with same technology and the desired output impedances for matching network are taken from the load-pull simulation results of this PA. The behavior of the amplifier has been optimized for 2.4 GHz (WLAN), 3.6 GHz (UWB-WiMAX) and 5.4 GHz (WLAN) frequency bands for high output power. Multi-band characteristic of the amplifier was obtained by using MOS based switching network. Two MOS switches are used for changing the behavior of the matching network and 4 possible states are achieved. Post-Layout simulation results of the PA circuit provided the following performance parameters: output power of 28-dBm, gain value of 26-dB and efficiency value of %19 for the 2.4 GHz WLAN band, output power of 28-dBm, gain value of 22-dB and efficiency value of %20 for the 3.6 GHz UWB-WiMAX band, and output power of 27-dBm, gain value of 23-dB and efficiency value of %17 for the 5.4 GHz WLAN band.

Research paper thumbnail of A 4.5-5.8 GHz Differential LC VCO using 0.35 μm SiGe BiCMOS Technology

In this paper, design and realization of a 4.5-5.8 GHz, -Gm LC voltage controlled oscillator (VCO... more In this paper, design and realization of a 4.5-5.8 GHz, -Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is implemented with AMS 0.35μm-SiGe BiCMOS process that includes high-speed SiGe heterojunction bipolar transistors (HBTs). A linear, 1300 MHz tuning range is measured with on-chip, accumulation-mode varactors. Fundamental frequency output power changes between -1.6 dBm and 0.9 dBm, depending on the tuning voltage. The circuit draws 17 mA from 3.3 V supply, including buffer circuits. Post-layout simulations of the VCO led to -110.7 dBc/Hz at 1MHz offset from 5.4 GHz carrier frequency and -113.4 dBc/Hz from 4.2 GHz carrier frequency of phase noise. The circuit occupies an area of 0.6 mm2, including RF and DC pads

Research paper thumbnail of Design of a tunable multi-band differential LC VCO using 0.35 µm SiGe BiCMOS technology for multi-standard wireless communication systems

Microelectronics Journal, 2009

In this paper, an integrated 2.2-5.7 GHz multi-band differential LC VCO for multi-standard wirele... more In this paper, an integrated 2.2-5.7 GHz multi-band differential LC VCO for multi-standard wireless communication systems was designed utilizing 0.35 mm SiGe BiCMOS technology. The topology, which combines the switching inductors and capacitors together in the same circuit, is a novel approach for wideband VCOs. Based on the post-layout simulation results, the VCO can be tuned using a DC voltage of 0 to 3.3 V for 5 different frequency bands (2.27-2.51 GHz, 2.48-2.78 GHz, 3.22-3.53 GHz, 3.48-3.91 GHz and 4.528-5.7 GHz) with a maximum bandwidth of 1.36 GHz and a minimum bandwidth of 300 MHz. The designed and simulated VCO can generate a differential output power between 0.992 and À6.087 dBm with an average power consumption of 44.21 mW including the buffers. The average second and third harmonics level were obtained as À37.21 and À47.6 dBm, respectively. The phase noise between À110.45 and À122.5 dBc/Hz, that was simulated at 1 MHz offset, can be obtained through the frequency of interest. Additionally, the figure of merit (FOM), that includes all important parameters such as the phase noise, the power consumption and the ratio of the operating frequency to the offset frequency, is between À176.48 and À181.16 and comparable or better than the ones with the other current VCOs. The main advantage of this study in comparison with the other VCOs, is covering 5 frequency bands starting from 2.27 up to 5.76 GHz without FOM and area abandonment. Output power of the fundamental frequency changes between À6.087 and 0.992 dBm, depending on the bias conditions (operating bands). Based on the post-layout simulation results, the core VCO circuit draws a current between 2.4-6.3 mA and between 11.4 and 15.3 mA with the buffer circuit from 3.3 V supply. The circuit occupies an area of 1.477 mm 2 on Si substrate, including DC, digital and RF pads.

Research paper thumbnail of Design of a 4.2–5.4 GHz differential LC VCO using 0.35 μm SiGe BiCMOS technology for IEEE 802.11a applications

International Journal of Rf and Microwave Computer-aided Engineering, 2007

In this paper, a 4.2–5.4 GHz, −Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standar... more In this paper, a 4.2–5.4 GHz, −Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is designed with AMS 0.35 μm SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). According to post-layout simulation results, phase noise is −110.7 dBc/Hz at 1 MHz offset from 5.4 GHz carrier frequency and −113.4 dBc/Hz from 4.2 GHz carrier frequency. A linear, 1200 MHz tuning range is obtained from the simulations, utilizing accumulation-mode varactors. Phase noise was also found to be relatively low because of taking advantage of differential tuning concept. Output power of the fundamental frequency changes between 4.8 dBm and 5.5 dBm depending on the tuning voltage. Based on the simulation results, the circuit draws 2 mA without buffers and 14.5 mA from 2.5 V supply including buffer circuits leading to a total power dissipation of 36.25 mW. The circuit layout occupies an area of 0.6 mm2 on Si substrate, including DC and RF pads. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.

Research paper thumbnail of Low Noise Amplifier Design Using 0.35 μm SiGe BiCMOS Technology for WLAN/WiMax Applications

This paper presents a design methodology of a low noise and low power fully-integrated LNA, targe... more This paper presents a design methodology of a low noise and low power fully-integrated LNA, targeted to all the three bands of IEEE 802.11a WLAN applications in the 5-6 GHz band and using 0.35µm SiGe BiCMOS HBT technology. We emphasized in this paper the importance extraction of parasitic components through the use of electromagnetic simulations, which is usually ignored in the literature of similar works/research when reporting noise figure. Finally, we have obtained a SiGe HBT on-chip matched LNA, exhibiting NF of 2.75 dB, gain of >15dB, input return loss of < -15dB, output return loss of < -10dB. The circuit consumes only 10.6 mW under 3.3V supply voltage. The circuit die area is 595 × 925 µm2, including pads.

Research paper thumbnail of A MEM varactor tuned-voltage controlled oscillator fabricated using 0.35μm SiGe BiCMOS technology

In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC volt... more In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC voltage controlled oscillator (VCO) is presented. The VCO is implemented with AMS 0.35 mum-SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). MEM- Varactor is fabricated in Sabanci University's cleanroom and includes six layers and five mask steps. MEM-Varactor and VCO is integrated on a FR4 substrate using wire bonder. With the actuation voltage of 0 to 10V, 70 MHz tuning range is measured from MEM-Varactor integrated VCO that is in the range 7.72 GHz to 7.80 GHz. Fundamental frequency output power changes between -2 dBm and 0 dBm, without the losses depending on the tuning voltage.

Research paper thumbnail of A MEM-varactor tuned, 7.8 GHz differential LC voltage-controlled oscillator

Sensors and Actuators A-physical, 2008

In this paper, design and realization of a parallel plate dual gap MEM-varactor tuned −Gm LC volt... more In this paper, design and realization of a parallel plate dual gap MEM-varactor tuned −Gm LC voltage controlled oscillator (VCO) is presented. The VCO is implemented with AMS 0.35μm-SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). MEM-varactor is fabricated by in-house capabilities and includes six layers and five mask steps. MEM-varactor and VCO is integrated on a

Research paper thumbnail of A MEM varactor tuned-voltage controlled oscillator fabricated using 0.35μm SiGe BiCMOS Technology

In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC volt... more In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC voltage controlled oscillator (VCO) is presented. The VCO is implemented with AMS 0.35 mum-SiGe BiCMOS process that includes high-speed SiGe heterojunction bipolar transistors (HBTs). MEM-Varactor is fabricated in Sabanci University's cleanroom and includes six layers and five mask steps. MEM-varactor and VCO is integrated on a FR4 substrate using wire bonder. With the actuation voltage of 0 to 10 V, 70 MHz tuning range is measured from MEM-varactor integrated VCO that is in the range 7.72 GHz to 7.80 GHz. Fundamental frequency output power changes between -2 dBm and 0 dBm, without the losses depending on the tuning voltage.

Research paper thumbnail of A coplanar waveguide on-chip RF choke for WLAN RF circuits

Microwave and Optical Technology Letters, 2007

A novel on-chip RF choke at 5 GHz is designed and measured for a class A operating Wireless LAN R... more A novel on-chip RF choke at 5 GHz is designed and measured for a class A operating Wireless LAN RF power amplifier (PA). The coplanar waveguide (CPW) based on-chip RF choke is implemented as an alternative component to inductors provided by the 0.35 µm SiGe BiCMOS technology. The CPW RF choke is designed at 5 GHz, and has a length of 1600 um and loaded with a capacitance of 0.95 pF. The measured impedance of the RF choke at 5 GHz is around 104 ohms.

Research paper thumbnail of Performance comparison of state-of-the-art heterojunction bipolar devices (HBT) based on AlGaAs/GaAs, Si/SiGe and InGaAs/InP

Microelectronics Journal, 2004

This paper presents a comprehensive comparison of three state-of-the-art heterojunction bipolar t... more This paper presents a comprehensive comparison of three state-of-the-art heterojunction bipolar transistors (HBTs); the AlGaAs/GaAs HBT, the Si/SiGe HBT and the InGaAs/InP HBT. Our aim in this paper is to find the potentials and limitations of these devices and analyze them under common Figure of Merit (FOM) definitions as well as to make a meaningful comparison which is necessary for a technology choice especially in RF-circuit and system level applications such as power amplifier, low noise amplifier circuits and transceiver/receiver systems. Simulation of an HBT device with an HBT model instead of traditional BJT models is also presented for the AlGaAs/GaAs HBT. To the best of our knowledge, this work covers the most extensive FOM analysis for these devices such as I-V behavior, stability, power gain analysis, characteristic frequencies and minimum noise figure. DC and bias point simulations of the devices are performed using Agilent's ADS design tool and a comparison is given for a wide range of FOM specifications. Based on our literature survey and simulation results, we have concluded that GaAs based HBTs are suitable for high-power applications due to their high-breakdown voltages, SiGe based HBTs are promising for low noise applications due to their low noise figures and InP will be the choice if very high-data rates is of primary importance since InP based HBT transistors have superior material properties leading to Terahertz frequency operation. q

Research paper thumbnail of Diamond semiconductor technology for RF device applications

Solid-state Electronics, 2005

This paper presents a comprehensive review of diamond electronics from the RF perspective. Our ai... more This paper presents a comprehensive review of diamond electronics from the RF perspective. Our aim was to find and present the potential, limitations and current status of diamond semiconductor devices as well as to investigate its suitability for RF device applications. While doing this, we briefly analysed the physics and chemistry of CVD diamond process for a better understanding of the reasons for the technological challenges of diamond material. This leads to Figure of Merit definitions which forms the basis for a technology choice in an RF device/system (such as transceiver or receiver) structure. Based on our literature survey, we concluded that, despite the technological challenges and few mentioned examples, diamond can seriously be considered as a base material for RF electronics, especially RF power circuits, where the important parameters are high speed, high power density, efficient thermal management and low signal loss in high power/frequencies. Simulation and experimental results are highly regarded for the surface acoustic wave (SAW) and field emission (FE) devices which already occupies space in the RF market and are likely to replace their conventional counterparts. Field effect transistors (FETs) are the most promising active devices and extremely high power densities are extracted (up to 30 W/mm). By the surface channel FET approach 81 GHz operation is developed. Bipolar devices are also promising if the deep doping problem can be solved for operation at room temperature. Pressure, thermal, chemical and acceleration sensors have already been demonstrated using micromachining/MEMS approach, but need more experimental results to better exploit thermal, physical/chemical and electronic properties of diamond.

Research paper thumbnail of A fully integrated multiband frequency synthesizer for WLAN and WiMAX applications

This paper presents a fractional N frequency synthesizer which covers WLAN and WiMAX frequencies ... more This paper presents a fractional N frequency synthesizer which covers WLAN and WiMAX frequencies on a single chip. The synthesizer is fully integrated in 0.35μm BiCMOS AMS technology except crystal oscillator. The synthesizer operates at four frequency bands (3.101-3.352GHz, 3.379-3.727GHz, 3.7-4.2GHz, 4.5-5.321GHz) to provide the specifications of 802.16 and 802.11 a/b/g/y. A single on-chip LC -Gm based VCO is implemented as the core of this synthesizer. Different frequency bands are selected via capacitance switching and fine tuning is done using varactor for each of these bands. A bandgap reference circuit is implemented inside of this charge pump block to generate temperature and power supply independent reference currents. Simulated settling time is around 10μsec. Total power consumption is measured to be 118.6mW without pad driving output buffers from a 3.3V supply. The phase noise of the oscillator is lower than -116.4dbc/Hz for all bands. The circuit occupies 2.784 mm 2 on Si substrate, including DC, Digital and RF pads.

Research paper thumbnail of A matching circuit tuned, multi-band (WLAN and WiMAX), Class — a power amplifier using 0.25μm-SiGe HBT technology

In this work, a MOS based output matching network is designed and fabricated using IHP (innovatio... more In this work, a MOS based output matching network is designed and fabricated using IHP (innovations for high performance), 0.25 mum-SiGe HBT process and measured which can give 4 different impedance values. Also, a multi-band, Class-A, power amplifier (PA) has been designed with same technology and the desired output impedances for matching network are taken from the load-pull simulation results of this PA. The behavior of the amplifier has been optimized for 2.4 GHz (WLAN), 3.6 GHz (UWB-WiMAX) and 5.4 GHz (WLAN) frequency bands for high output power. Multi-band characteristic of the amplifier was obtained by using MOS based switching network. Two MOS switches are used for changing the behavior of the matching network and 4 possible states are achieved. Post-Layout simulation results of the PA circuit provided the following performance parameters: output power of 28-dBm, gain value of 26-dB and efficiency value of %19 for the 2.4 GHz WLAN band, output power of 28-dBm, gain value of 22-dB and efficiency value of %20 for the 3.6 GHz UWB-WiMAX band, and output power of 27-dBm, gain value of 23-dB and efficiency value of %17 for the 5.4 GHz WLAN band.

Research paper thumbnail of A 4.5-5.8 GHz Differential LC VCO using 0.35 μm SiGe BiCMOS Technology

In this paper, design and realization of a 4.5-5.8 GHz, -Gm LC voltage controlled oscillator (VCO... more In this paper, design and realization of a 4.5-5.8 GHz, -Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is implemented with AMS 0.35μm-SiGe BiCMOS process that includes high-speed SiGe heterojunction bipolar transistors (HBTs). A linear, 1300 MHz tuning range is measured with on-chip, accumulation-mode varactors. Fundamental frequency output power changes between -1.6 dBm and 0.9 dBm, depending on the tuning voltage. The circuit draws 17 mA from 3.3 V supply, including buffer circuits. Post-layout simulations of the VCO led to -110.7 dBc/Hz at 1MHz offset from 5.4 GHz carrier frequency and -113.4 dBc/Hz from 4.2 GHz carrier frequency of phase noise. The circuit occupies an area of 0.6 mm2, including RF and DC pads

Research paper thumbnail of Design of a tunable multi-band differential LC VCO using 0.35 µm SiGe BiCMOS technology for multi-standard wireless communication systems

Microelectronics Journal, 2009

In this paper, an integrated 2.2-5.7 GHz multi-band differential LC VCO for multi-standard wirele... more In this paper, an integrated 2.2-5.7 GHz multi-band differential LC VCO for multi-standard wireless communication systems was designed utilizing 0.35 mm SiGe BiCMOS technology. The topology, which combines the switching inductors and capacitors together in the same circuit, is a novel approach for wideband VCOs. Based on the post-layout simulation results, the VCO can be tuned using a DC voltage of 0 to 3.3 V for 5 different frequency bands (2.27-2.51 GHz, 2.48-2.78 GHz, 3.22-3.53 GHz, 3.48-3.91 GHz and 4.528-5.7 GHz) with a maximum bandwidth of 1.36 GHz and a minimum bandwidth of 300 MHz. The designed and simulated VCO can generate a differential output power between 0.992 and À6.087 dBm with an average power consumption of 44.21 mW including the buffers. The average second and third harmonics level were obtained as À37.21 and À47.6 dBm, respectively. The phase noise between À110.45 and À122.5 dBc/Hz, that was simulated at 1 MHz offset, can be obtained through the frequency of interest. Additionally, the figure of merit (FOM), that includes all important parameters such as the phase noise, the power consumption and the ratio of the operating frequency to the offset frequency, is between À176.48 and À181.16 and comparable or better than the ones with the other current VCOs. The main advantage of this study in comparison with the other VCOs, is covering 5 frequency bands starting from 2.27 up to 5.76 GHz without FOM and area abandonment. Output power of the fundamental frequency changes between À6.087 and 0.992 dBm, depending on the bias conditions (operating bands). Based on the post-layout simulation results, the core VCO circuit draws a current between 2.4-6.3 mA and between 11.4 and 15.3 mA with the buffer circuit from 3.3 V supply. The circuit occupies an area of 1.477 mm 2 on Si substrate, including DC, digital and RF pads.

Research paper thumbnail of Design of a 4.2–5.4 GHz differential LC VCO using 0.35 μm SiGe BiCMOS technology for IEEE 802.11a applications

International Journal of Rf and Microwave Computer-aided Engineering, 2007

In this paper, a 4.2–5.4 GHz, −Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standar... more In this paper, a 4.2–5.4 GHz, −Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is designed with AMS 0.35 μm SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). According to post-layout simulation results, phase noise is −110.7 dBc/Hz at 1 MHz offset from 5.4 GHz carrier frequency and −113.4 dBc/Hz from 4.2 GHz carrier frequency. A linear, 1200 MHz tuning range is obtained from the simulations, utilizing accumulation-mode varactors. Phase noise was also found to be relatively low because of taking advantage of differential tuning concept. Output power of the fundamental frequency changes between 4.8 dBm and 5.5 dBm depending on the tuning voltage. Based on the simulation results, the circuit draws 2 mA without buffers and 14.5 mA from 2.5 V supply including buffer circuits leading to a total power dissipation of 36.25 mW. The circuit layout occupies an area of 0.6 mm2 on Si substrate, including DC and RF pads. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.

Research paper thumbnail of Low Noise Amplifier Design Using 0.35 μm SiGe BiCMOS Technology for WLAN/WiMax Applications

This paper presents a design methodology of a low noise and low power fully-integrated LNA, targe... more This paper presents a design methodology of a low noise and low power fully-integrated LNA, targeted to all the three bands of IEEE 802.11a WLAN applications in the 5-6 GHz band and using 0.35µm SiGe BiCMOS HBT technology. We emphasized in this paper the importance extraction of parasitic components through the use of electromagnetic simulations, which is usually ignored in the literature of similar works/research when reporting noise figure. Finally, we have obtained a SiGe HBT on-chip matched LNA, exhibiting NF of 2.75 dB, gain of >15dB, input return loss of < -15dB, output return loss of < -10dB. The circuit consumes only 10.6 mW under 3.3V supply voltage. The circuit die area is 595 × 925 µm2, including pads.

Research paper thumbnail of A MEM varactor tuned-voltage controlled oscillator fabricated using 0.35μm SiGe BiCMOS technology

In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC volt... more In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC voltage controlled oscillator (VCO) is presented. The VCO is implemented with AMS 0.35 mum-SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). MEM- Varactor is fabricated in Sabanci University's cleanroom and includes six layers and five mask steps. MEM-Varactor and VCO is integrated on a FR4 substrate using wire bonder. With the actuation voltage of 0 to 10V, 70 MHz tuning range is measured from MEM-Varactor integrated VCO that is in the range 7.72 GHz to 7.80 GHz. Fundamental frequency output power changes between -2 dBm and 0 dBm, without the losses depending on the tuning voltage.

Research paper thumbnail of Diamond semiconductor technology for RF device applications

Solid-state Electronics, 2005

This paper presents a comprehensive review of diamond electronics from the RF perspective. Our ai... more This paper presents a comprehensive review of diamond electronics from the RF perspective. Our aim was to find and present the potential, limitations and current status of diamond semiconductor devices as well as to investigate its suitability for RF device applications. While doing this, we briefly analysed the physics and chemistry of CVD diamond process for a better understanding of the reasons for the technological challenges of diamond material. This leads to Figure of Merit definitions which forms the basis for a technology choice in an RF device/system (such as transceiver or receiver) structure. Based on our literature survey, we concluded that, despite the technological challenges and few mentioned examples, diamond can seriously be considered as a base material for RF electronics, especially RF power circuits, where the important parameters are high speed, high power density, efficient thermal management and low signal loss in high power/frequencies. Simulation and experimental results are highly regarded for the surface acoustic wave (SAW) and field emission (FE) devices which already occupies space in the RF market and are likely to replace their conventional counterparts. Field effect transistors (FETs) are the most promising active devices and extremely high power densities are extracted (up to 30 W/mm). By the surface channel FET approach 81 GHz operation is developed. Bipolar devices are also promising if the deep doping problem can be solved for operation at room temperature. Pressure, thermal, chemical and acceleration sensors have already been demonstrated using micromachining/MEMS approach, but need more experimental results to better exploit thermal, physical/chemical and electronic properties of diamond.

Research paper thumbnail of A fully integrated multiband frequency synthesizer for WLAN and WiMAX applications

This paper presents a fractional N frequency synthesizer which covers WLAN and WiMAX frequencies ... more This paper presents a fractional N frequency synthesizer which covers WLAN and WiMAX frequencies on a single chip. The synthesizer is fully integrated in 0.35μm BiCMOS AMS technology except crystal oscillator. The synthesizer operates at four frequency bands (3.101-3.352GHz, 3.379-3.727GHz, 3.7-4.2GHz, 4.5-5.321GHz) to provide the specifications of 802.16 and 802.11 a/b/g/y. A single on-chip LC -Gm based VCO is implemented as the core of this synthesizer. Different frequency bands are selected via capacitance switching and fine tuning is done using varactor for each of these bands. A bandgap reference circuit is implemented inside of this charge pump block to generate temperature and power supply independent reference currents. Simulated settling time is around 10μsec. Total power consumption is measured to be 118.6mW without pad driving output buffers from a 3.3V supply. The phase noise of the oscillator is lower than -116.4dbc/Hz for all bands. The circuit occupies 2.784 mm 2 on Si substrate, including DC, Digital and RF pads.

Research paper thumbnail of A matching circuit tuned, multi-band (WLAN and WiMAX), Class — a power amplifier using 0.25μm-SiGe HBT technology

In this work, a MOS based output matching network is designed and fabricated using IHP (innovatio... more In this work, a MOS based output matching network is designed and fabricated using IHP (innovations for high performance), 0.25 mum-SiGe HBT process and measured which can give 4 different impedance values. Also, a multi-band, Class-A, power amplifier (PA) has been designed with same technology and the desired output impedances for matching network are taken from the load-pull simulation results of this PA. The behavior of the amplifier has been optimized for 2.4 GHz (WLAN), 3.6 GHz (UWB-WiMAX) and 5.4 GHz (WLAN) frequency bands for high output power. Multi-band characteristic of the amplifier was obtained by using MOS based switching network. Two MOS switches are used for changing the behavior of the matching network and 4 possible states are achieved. Post-Layout simulation results of the PA circuit provided the following performance parameters: output power of 28-dBm, gain value of 26-dB and efficiency value of %19 for the 2.4 GHz WLAN band, output power of 28-dBm, gain value of 22-dB and efficiency value of %20 for the 3.6 GHz UWB-WiMAX band, and output power of 27-dBm, gain value of 23-dB and efficiency value of %17 for the 5.4 GHz WLAN band.

Research paper thumbnail of A 4.5-5.8 GHz Differential LC VCO using 0.35 μm SiGe BiCMOS Technology

In this paper, design and realization of a 4.5-5.8 GHz, -Gm LC voltage controlled oscillator (VCO... more In this paper, design and realization of a 4.5-5.8 GHz, -Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is implemented with AMS 0.35μm-SiGe BiCMOS process that includes high-speed SiGe heterojunction bipolar transistors (HBTs). A linear, 1300 MHz tuning range is measured with on-chip, accumulation-mode varactors. Fundamental frequency output power changes between -1.6 dBm and 0.9 dBm, depending on the tuning voltage. The circuit draws 17 mA from 3.3 V supply, including buffer circuits. Post-layout simulations of the VCO led to -110.7 dBc/Hz at 1MHz offset from 5.4 GHz carrier frequency and -113.4 dBc/Hz from 4.2 GHz carrier frequency of phase noise. The circuit occupies an area of 0.6 mm2, including RF and DC pads

Research paper thumbnail of Design of a tunable multi-band differential LC VCO using 0.35 µm SiGe BiCMOS technology for multi-standard wireless communication systems

Microelectronics Journal, 2009

In this paper, an integrated 2.2-5.7 GHz multi-band differential LC VCO for multi-standard wirele... more In this paper, an integrated 2.2-5.7 GHz multi-band differential LC VCO for multi-standard wireless communication systems was designed utilizing 0.35 mm SiGe BiCMOS technology. The topology, which combines the switching inductors and capacitors together in the same circuit, is a novel approach for wideband VCOs. Based on the post-layout simulation results, the VCO can be tuned using a DC voltage of 0 to 3.3 V for 5 different frequency bands (2.27-2.51 GHz, 2.48-2.78 GHz, 3.22-3.53 GHz, 3.48-3.91 GHz and 4.528-5.7 GHz) with a maximum bandwidth of 1.36 GHz and a minimum bandwidth of 300 MHz. The designed and simulated VCO can generate a differential output power between 0.992 and À6.087 dBm with an average power consumption of 44.21 mW including the buffers. The average second and third harmonics level were obtained as À37.21 and À47.6 dBm, respectively. The phase noise between À110.45 and À122.5 dBc/Hz, that was simulated at 1 MHz offset, can be obtained through the frequency of interest. Additionally, the figure of merit (FOM), that includes all important parameters such as the phase noise, the power consumption and the ratio of the operating frequency to the offset frequency, is between À176.48 and À181.16 and comparable or better than the ones with the other current VCOs. The main advantage of this study in comparison with the other VCOs, is covering 5 frequency bands starting from 2.27 up to 5.76 GHz without FOM and area abandonment. Output power of the fundamental frequency changes between À6.087 and 0.992 dBm, depending on the bias conditions (operating bands). Based on the post-layout simulation results, the core VCO circuit draws a current between 2.4-6.3 mA and between 11.4 and 15.3 mA with the buffer circuit from 3.3 V supply. The circuit occupies an area of 1.477 mm 2 on Si substrate, including DC, digital and RF pads.

Research paper thumbnail of Design of a 4.2–5.4 GHz differential LC VCO using 0.35 μm SiGe BiCMOS technology for IEEE 802.11a applications

International Journal of Rf and Microwave Computer-aided Engineering, 2007

In this paper, a 4.2–5.4 GHz, −Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standar... more In this paper, a 4.2–5.4 GHz, −Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is designed with AMS 0.35 μm SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). According to post-layout simulation results, phase noise is −110.7 dBc/Hz at 1 MHz offset from 5.4 GHz carrier frequency and −113.4 dBc/Hz from 4.2 GHz carrier frequency. A linear, 1200 MHz tuning range is obtained from the simulations, utilizing accumulation-mode varactors. Phase noise was also found to be relatively low because of taking advantage of differential tuning concept. Output power of the fundamental frequency changes between 4.8 dBm and 5.5 dBm depending on the tuning voltage. Based on the simulation results, the circuit draws 2 mA without buffers and 14.5 mA from 2.5 V supply including buffer circuits leading to a total power dissipation of 36.25 mW. The circuit layout occupies an area of 0.6 mm2 on Si substrate, including DC and RF pads. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.

Research paper thumbnail of Low Noise Amplifier Design Using 0.35 μm SiGe BiCMOS Technology for WLAN/WiMax Applications

This paper presents a design methodology of a low noise and low power fully-integrated LNA, targe... more This paper presents a design methodology of a low noise and low power fully-integrated LNA, targeted to all the three bands of IEEE 802.11a WLAN applications in the 5-6 GHz band and using 0.35µm SiGe BiCMOS HBT technology. We emphasized in this paper the importance extraction of parasitic components through the use of electromagnetic simulations, which is usually ignored in the literature of similar works/research when reporting noise figure. Finally, we have obtained a SiGe HBT on-chip matched LNA, exhibiting NF of 2.75 dB, gain of >15dB, input return loss of < -15dB, output return loss of < -10dB. The circuit consumes only 10.6 mW under 3.3V supply voltage. The circuit die area is 595 × 925 µm2, including pads.

Research paper thumbnail of A MEM varactor tuned-voltage controlled oscillator fabricated using 0.35μm SiGe BiCMOS technology

In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC volt... more In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC voltage controlled oscillator (VCO) is presented. The VCO is implemented with AMS 0.35 mum-SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). MEM- Varactor is fabricated in Sabanci University's cleanroom and includes six layers and five mask steps. MEM-Varactor and VCO is integrated on a FR4 substrate using wire bonder. With the actuation voltage of 0 to 10V, 70 MHz tuning range is measured from MEM-Varactor integrated VCO that is in the range 7.72 GHz to 7.80 GHz. Fundamental frequency output power changes between -2 dBm and 0 dBm, without the losses depending on the tuning voltage.

Research paper thumbnail of A MEM-varactor tuned, 7.8 GHz differential LC voltage-controlled oscillator

Sensors and Actuators A-physical, 2008

In this paper, design and realization of a parallel plate dual gap MEM-varactor tuned −Gm LC volt... more In this paper, design and realization of a parallel plate dual gap MEM-varactor tuned −Gm LC voltage controlled oscillator (VCO) is presented. The VCO is implemented with AMS 0.35μm-SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). MEM-varactor is fabricated by in-house capabilities and includes six layers and five mask steps. MEM-varactor and VCO is integrated on a

Research paper thumbnail of A MEM varactor tuned-voltage controlled oscillator fabricated using 0.35μm SiGe BiCMOS Technology

In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC volt... more In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC voltage controlled oscillator (VCO) is presented. The VCO is implemented with AMS 0.35 mum-SiGe BiCMOS process that includes high-speed SiGe heterojunction bipolar transistors (HBTs). MEM-Varactor is fabricated in Sabanci University's cleanroom and includes six layers and five mask steps. MEM-varactor and VCO is integrated on a FR4 substrate using wire bonder. With the actuation voltage of 0 to 10 V, 70 MHz tuning range is measured from MEM-varactor integrated VCO that is in the range 7.72 GHz to 7.80 GHz. Fundamental frequency output power changes between -2 dBm and 0 dBm, without the losses depending on the tuning voltage.

Research paper thumbnail of A coplanar waveguide on-chip RF choke for WLAN RF circuits

Microwave and Optical Technology Letters, 2007

A novel on-chip RF choke at 5 GHz is designed and measured for a class A operating Wireless LAN R... more A novel on-chip RF choke at 5 GHz is designed and measured for a class A operating Wireless LAN RF power amplifier (PA). The coplanar waveguide (CPW) based on-chip RF choke is implemented as an alternative component to inductors provided by the 0.35 µm SiGe BiCMOS technology. The CPW RF choke is designed at 5 GHz, and has a length of 1600 um and loaded with a capacitance of 0.95 pF. The measured impedance of the RF choke at 5 GHz is around 104 ohms.

Research paper thumbnail of Performance comparison of state-of-the-art heterojunction bipolar devices (HBT) based on AlGaAs/GaAs, Si/SiGe and InGaAs/InP

Microelectronics Journal, 2004

This paper presents a comprehensive comparison of three state-of-the-art heterojunction bipolar t... more This paper presents a comprehensive comparison of three state-of-the-art heterojunction bipolar transistors (HBTs); the AlGaAs/GaAs HBT, the Si/SiGe HBT and the InGaAs/InP HBT. Our aim in this paper is to find the potentials and limitations of these devices and analyze them under common Figure of Merit (FOM) definitions as well as to make a meaningful comparison which is necessary for a technology choice especially in RF-circuit and system level applications such as power amplifier, low noise amplifier circuits and transceiver/receiver systems. Simulation of an HBT device with an HBT model instead of traditional BJT models is also presented for the AlGaAs/GaAs HBT. To the best of our knowledge, this work covers the most extensive FOM analysis for these devices such as I-V behavior, stability, power gain analysis, characteristic frequencies and minimum noise figure. DC and bias point simulations of the devices are performed using Agilent's ADS design tool and a comparison is given for a wide range of FOM specifications. Based on our literature survey and simulation results, we have concluded that GaAs based HBTs are suitable for high-power applications due to their high-breakdown voltages, SiGe based HBTs are promising for low noise applications due to their low noise figures and InP will be the choice if very high-data rates is of primary importance since InP based HBT transistors have superior material properties leading to Terahertz frequency operation. q

Research paper thumbnail of Diamond semiconductor technology for RF device applications

Solid-state Electronics, 2005

This paper presents a comprehensive review of diamond electronics from the RF perspective. Our ai... more This paper presents a comprehensive review of diamond electronics from the RF perspective. Our aim was to find and present the potential, limitations and current status of diamond semiconductor devices as well as to investigate its suitability for RF device applications. While doing this, we briefly analysed the physics and chemistry of CVD diamond process for a better understanding of the reasons for the technological challenges of diamond material. This leads to Figure of Merit definitions which forms the basis for a technology choice in an RF device/system (such as transceiver or receiver) structure. Based on our literature survey, we concluded that, despite the technological challenges and few mentioned examples, diamond can seriously be considered as a base material for RF electronics, especially RF power circuits, where the important parameters are high speed, high power density, efficient thermal management and low signal loss in high power/frequencies. Simulation and experimental results are highly regarded for the surface acoustic wave (SAW) and field emission (FE) devices which already occupies space in the RF market and are likely to replace their conventional counterparts. Field effect transistors (FETs) are the most promising active devices and extremely high power densities are extracted (up to 30 W/mm). By the surface channel FET approach 81 GHz operation is developed. Bipolar devices are also promising if the deep doping problem can be solved for operation at room temperature. Pressure, thermal, chemical and acceleration sensors have already been demonstrated using micromachining/MEMS approach, but need more experimental results to better exploit thermal, physical/chemical and electronic properties of diamond.

Research paper thumbnail of A fully integrated multiband frequency synthesizer for WLAN and WiMAX applications

This paper presents a fractional N frequency synthesizer which covers WLAN and WiMAX frequencies ... more This paper presents a fractional N frequency synthesizer which covers WLAN and WiMAX frequencies on a single chip. The synthesizer is fully integrated in 0.35μm BiCMOS AMS technology except crystal oscillator. The synthesizer operates at four frequency bands (3.101-3.352GHz, 3.379-3.727GHz, 3.7-4.2GHz, 4.5-5.321GHz) to provide the specifications of 802.16 and 802.11 a/b/g/y. A single on-chip LC -Gm based VCO is implemented as the core of this synthesizer. Different frequency bands are selected via capacitance switching and fine tuning is done using varactor for each of these bands. A bandgap reference circuit is implemented inside of this charge pump block to generate temperature and power supply independent reference currents. Simulated settling time is around 10μsec. Total power consumption is measured to be 118.6mW without pad driving output buffers from a 3.3V supply. The phase noise of the oscillator is lower than -116.4dbc/Hz for all bands. The circuit occupies 2.784 mm 2 on Si substrate, including DC, Digital and RF pads.

Research paper thumbnail of A matching circuit tuned, multi-band (WLAN and WiMAX), Class — a power amplifier using 0.25μm-SiGe HBT technology

In this work, a MOS based output matching network is designed and fabricated using IHP (innovatio... more In this work, a MOS based output matching network is designed and fabricated using IHP (innovations for high performance), 0.25 mum-SiGe HBT process and measured which can give 4 different impedance values. Also, a multi-band, Class-A, power amplifier (PA) has been designed with same technology and the desired output impedances for matching network are taken from the load-pull simulation results of this PA. The behavior of the amplifier has been optimized for 2.4 GHz (WLAN), 3.6 GHz (UWB-WiMAX) and 5.4 GHz (WLAN) frequency bands for high output power. Multi-band characteristic of the amplifier was obtained by using MOS based switching network. Two MOS switches are used for changing the behavior of the matching network and 4 possible states are achieved. Post-Layout simulation results of the PA circuit provided the following performance parameters: output power of 28-dBm, gain value of 26-dB and efficiency value of %19 for the 2.4 GHz WLAN band, output power of 28-dBm, gain value of 22-dB and efficiency value of %20 for the 3.6 GHz UWB-WiMAX band, and output power of 27-dBm, gain value of 23-dB and efficiency value of %17 for the 5.4 GHz WLAN band.

Research paper thumbnail of A 4.5-5.8 GHz Differential LC VCO using 0.35 μm SiGe BiCMOS Technology

In this paper, design and realization of a 4.5-5.8 GHz, -Gm LC voltage controlled oscillator (VCO... more In this paper, design and realization of a 4.5-5.8 GHz, -Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is implemented with AMS 0.35μm-SiGe BiCMOS process that includes high-speed SiGe heterojunction bipolar transistors (HBTs). A linear, 1300 MHz tuning range is measured with on-chip, accumulation-mode varactors. Fundamental frequency output power changes between -1.6 dBm and 0.9 dBm, depending on the tuning voltage. The circuit draws 17 mA from 3.3 V supply, including buffer circuits. Post-layout simulations of the VCO led to -110.7 dBc/Hz at 1MHz offset from 5.4 GHz carrier frequency and -113.4 dBc/Hz from 4.2 GHz carrier frequency of phase noise. The circuit occupies an area of 0.6 mm2, including RF and DC pads

Research paper thumbnail of Design of a tunable multi-band differential LC VCO using 0.35 µm SiGe BiCMOS technology for multi-standard wireless communication systems

Microelectronics Journal, 2009

In this paper, an integrated 2.2-5.7 GHz multi-band differential LC VCO for multi-standard wirele... more In this paper, an integrated 2.2-5.7 GHz multi-band differential LC VCO for multi-standard wireless communication systems was designed utilizing 0.35 mm SiGe BiCMOS technology. The topology, which combines the switching inductors and capacitors together in the same circuit, is a novel approach for wideband VCOs. Based on the post-layout simulation results, the VCO can be tuned using a DC voltage of 0 to 3.3 V for 5 different frequency bands (2.27-2.51 GHz, 2.48-2.78 GHz, 3.22-3.53 GHz, 3.48-3.91 GHz and 4.528-5.7 GHz) with a maximum bandwidth of 1.36 GHz and a minimum bandwidth of 300 MHz. The designed and simulated VCO can generate a differential output power between 0.992 and À6.087 dBm with an average power consumption of 44.21 mW including the buffers. The average second and third harmonics level were obtained as À37.21 and À47.6 dBm, respectively. The phase noise between À110.45 and À122.5 dBc/Hz, that was simulated at 1 MHz offset, can be obtained through the frequency of interest. Additionally, the figure of merit (FOM), that includes all important parameters such as the phase noise, the power consumption and the ratio of the operating frequency to the offset frequency, is between À176.48 and À181.16 and comparable or better than the ones with the other current VCOs. The main advantage of this study in comparison with the other VCOs, is covering 5 frequency bands starting from 2.27 up to 5.76 GHz without FOM and area abandonment. Output power of the fundamental frequency changes between À6.087 and 0.992 dBm, depending on the bias conditions (operating bands). Based on the post-layout simulation results, the core VCO circuit draws a current between 2.4-6.3 mA and between 11.4 and 15.3 mA with the buffer circuit from 3.3 V supply. The circuit occupies an area of 1.477 mm 2 on Si substrate, including DC, digital and RF pads.

Research paper thumbnail of Design of a 4.2–5.4 GHz differential LC VCO using 0.35 μm SiGe BiCMOS technology for IEEE 802.11a applications

International Journal of Rf and Microwave Computer-aided Engineering, 2007

In this paper, a 4.2–5.4 GHz, −Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standar... more In this paper, a 4.2–5.4 GHz, −Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is designed with AMS 0.35 μm SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). According to post-layout simulation results, phase noise is −110.7 dBc/Hz at 1 MHz offset from 5.4 GHz carrier frequency and −113.4 dBc/Hz from 4.2 GHz carrier frequency. A linear, 1200 MHz tuning range is obtained from the simulations, utilizing accumulation-mode varactors. Phase noise was also found to be relatively low because of taking advantage of differential tuning concept. Output power of the fundamental frequency changes between 4.8 dBm and 5.5 dBm depending on the tuning voltage. Based on the simulation results, the circuit draws 2 mA without buffers and 14.5 mA from 2.5 V supply including buffer circuits leading to a total power dissipation of 36.25 mW. The circuit layout occupies an area of 0.6 mm2 on Si substrate, including DC and RF pads. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.

Research paper thumbnail of Low Noise Amplifier Design Using 0.35 μm SiGe BiCMOS Technology for WLAN/WiMax Applications

This paper presents a design methodology of a low noise and low power fully-integrated LNA, targe... more This paper presents a design methodology of a low noise and low power fully-integrated LNA, targeted to all the three bands of IEEE 802.11a WLAN applications in the 5-6 GHz band and using 0.35µm SiGe BiCMOS HBT technology. We emphasized in this paper the importance extraction of parasitic components through the use of electromagnetic simulations, which is usually ignored in the literature of similar works/research when reporting noise figure. Finally, we have obtained a SiGe HBT on-chip matched LNA, exhibiting NF of 2.75 dB, gain of >15dB, input return loss of < -15dB, output return loss of < -10dB. The circuit consumes only 10.6 mW under 3.3V supply voltage. The circuit die area is 595 × 925 µm2, including pads.

Research paper thumbnail of A MEM varactor tuned-voltage controlled oscillator fabricated using 0.35μm SiGe BiCMOS technology

In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC volt... more In this paper, design and realization of a parallel plate dual gap MEM-Varactor based -Gm LC voltage controlled oscillator (VCO) is presented. The VCO is implemented with AMS 0.35 mum-SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). MEM- Varactor is fabricated in Sabanci University's cleanroom and includes six layers and five mask steps. MEM-Varactor and VCO is integrated on a FR4 substrate using wire bonder. With the actuation voltage of 0 to 10V, 70 MHz tuning range is measured from MEM-Varactor integrated VCO that is in the range 7.72 GHz to 7.80 GHz. Fundamental frequency output power changes between -2 dBm and 0 dBm, without the losses depending on the tuning voltage.