Ramazan Kopru | Isik University (original) (raw)
Papers by Ramazan Kopru
In order to maximize efficiency of the designed gyrator-based active inductor, advanced circuit t... more In order to maximize efficiency of the designed gyrator-based active inductor, advanced circuit techniques are used. Loss and noise are most important features of the AIs, where they should be low enough to have high-performance device. The gyrator-C topology is used to design a new low-loss and low-noise active inductor. The gyrator-C topology is potentially high-Q and all transistors are utilized in common-source configuration to have high impedance in input-output nodes. All transistors are free of body effect. The p-type differential pair input transistors and the feed forward path are employed to decrease noise of the proposed circuit. Additionally, inductance value and quality factor are adjusted by variation bias current which gives to the device tunable capability. HSPICE simulation results are presented to verify the performance of the circuit, where the 180 nm CMOS process and 1.8 V power supply are used. The noise voltage and power dissipation are less than 2.8 nV/ √ Hz and 1.3 mW, respectively.
Circuits Systems and Signal Processing, Sep 8, 2017
An accurate CMOS interface small capacitance variation sensing circuit for capacitive MEMS sensor... more An accurate CMOS interface small capacitance variation sensing circuit for capacitive MEMS sensor applications An accurate front-end CMOS interface circuit for sensing very small capacitance changes in capacitive sensors is presented in this paper. The proposed structure scales capacitance variation to the sensible impedance changing. The scaling factor of the circuit can be easily tuned by adjusting bias points of the transistors. In order to cancel or decrease the parasitic components, the RC feedback and input transistor cascading techniques are used in the design. To simulate the circuit, HSPICE simulator is utilized to verify the validity of the theoretical formulations in 0.18 µm technology. According to schematic and post layout simulation results input impedance changes linearly versus capacitance variations up to 0.7 GHz while the sensor capacitance changing is varied between 0~200fF. Total dc power consumption is obtained as low as 1.2 mW with 1.8 V power supply.
Analog Integrated Circuits and Signal Processing, Jun 2, 2016
In this paper, a 50 X terminated or in other words transformerless bandpass matching network desi... more In this paper, a 50 X terminated or in other words transformerless bandpass matching network design methodology and an implementation example are presented. The real frequency techniques are powerful numerical methods to design wideband lossless two-port networks such as filters, matching networks and amplifiers. In these techniques, the value of the termination resistance of the designed network could not be yielded as 50 X by numerical package. Hence, a transformer is also required for 50 X termination which is not practical for high frequency applications. By employing the proposed procedure, it is guaranteed to obtain transformerless bandpass matching network. Also in this study a wideband suspended monopole antenna is examined. The proposed antenna consists of two major elements; Y-shaped impedance matching plate and hemi-circular radiator. Moreover Y-shaped impedance matching plate connected to a feeding probe excites the suspended hemi-circular radiator via air gap. Consequently, a transformerless bandpass matching network is designed to filter and expand the operational frequency bandwidth of the proposed antenna. It has been observed that ideal circuit and the layout of the matching network simulation have good agreement.
Integration, 2017
This work presents a new low-loss active inductor whose self-resonance frequency and quality fact... more This work presents a new low-loss active inductor whose self-resonance frequency and quality factor parameters can be adjusted independently from each other. In order to achieve this property, a new input topology has been employed which consists of cascode structure with a diode connected transistor. Furthermore, the proposed input topology makes the device robust in terms of its performance over variation in process, voltage and temperature. Additionally, RC feedback is used to cancel series-loss resistance of the active inductor, which allows self-resonant enhancement as well. Schematic and post-layout simulation results show the theoretical validity of the design. To validate the design feasibility for process, voltage and temperature changes, Monte Carlo and temperature analysis are done. Suggested structure shows inductor behavior in the frequency range of 0.3-11.3 GHz. Maximum quality factor is obtained as high as 2.1k at 5.9 GHz. Total power consumption is as low as 1mW with 1.8 V power supply.
2016 National Conference on Electrical, Electronics and Biomedical Engineering (ELECO), 2016
Nowadays design of communication instruments that use for communication show a great improvement ... more Nowadays design of communication instruments that use for communication show a great improvement and change. Communication instruments consist of many systems. At this study, microwave amplifier design that has a great important as system carry out for supply communication. Microwave amplifier design carry out for cellular communication in the range of 0.8–1.9 GHz bandwith. Amplifier circuit design by using ADS program. Amplifier circuit consist of ideal circuit, microstrip circuit, layout circuit and circuit production. At this study, results of production of acquired design resemble to results of program design.
2019 International Conference on Power Generation Systems and Renewable Energy Technologies (PGSRET)
Design and simulation of a microwave wideband microstrip unit element bandpass matching network i... more Design and simulation of a microwave wideband microstrip unit element bandpass matching network is presented, potential use might be a broadband WPT (microwave wireless power transfer) application in X-band frequencies (8-12 GHz). The source of the main energy can be wind, fossil, tidal, solar, nuclear, hydro etc. and the main energy can be converted from DC to microwave energy which then can be transmitted via the proposed WPT circuit towards a few or a network of a multiple microwave harvester receivers located at a near or far field from the main source. In the work, a bandpass matching network (BPMN) composed of microstrip "unit elements (UEs)" is designed to operate along the whole X-band (8-12 GHz). Designed BPMN is excited by an X-band commercial PA (power amplifier) MMIC (monolithic microwave integrated circuit) packaged chip, and it is loaded by an X-band microstrip patch antenna. A bond wire soldered between the RF output pad of MMIC chip and the input pad of the BPMN has an equivalent LC parasitic impedance assumed to be the generator complex impedance that must be compensated in a typical matching problem. SRFT (simplified real frequency technique) is used in the design of the matching network that compensates the effect of bond wire and very good agreement found between the theoretical design and simulations done in MWO (AWR).
Istanbul University - Journal of Electrical and Electronics Engineering, 2016
This work is the continuation of our high precision immittance synthesis paper series introduced ... more This work is the continuation of our high precision immittance synthesis paper series introduced in IEEE TCAS-I. In the present manuscript, we modified the previously introduced high precision Bandpass LC-ladder synthesis algorithm to include the extraction of finite frequency and right half plane (RHP) transmission zeros of an impedance function as Brune/Darlington Type-C sections. Finite frequency and RHP transmission zeros are extracted employing our newly introduced modified impedance and chain parameters based algorithms one by one. After each transmission zero extraction, remaining immittance function is corrected using parametric approach. It is shown that propsed high precision synthesis algorithms can synthesize immittance functions up to 40 reactive elements with accumulated relative error in the order of 10 - 1 . The modified high precision synthesis package is developed in MatLab environment and it is integrated with the real frequency techniques to design matching netwo...
International Journal of Electronics Letters, 2016
An accurate CMOS interface small capacitance variation sensing circuit for capacitive MEMS sensor... more An accurate CMOS interface small capacitance variation sensing circuit for capacitive MEMS sensor applications An accurate front-end CMOS interface circuit for sensing very small capacitance changes in capacitive sensors is presented in this paper. The proposed structure scales capacitance variation to the sensible impedance changing. The scaling factor of the circuit can be easily tuned by adjusting bias points of the transistors. In order to cancel or decrease the parasitic components, the RC feedback and input transistor cascading techniques are used in the design. To simulate the circuit, HSPICE simulator is utilized to verify the validity of the theoretical formulations in 0.18 µm technology. According to schematic and post layout simulation results input impedance changes linearly versus capacitance variations up to 0.7 GHz while the sensor capacitance changing is varied between 0~200fF. Total dc power consumption is obtained as low as 1.2 mW with 1.8 V power supply.
In this work, we propose a novel approach called “Normalized Gain Function (NGF) method” to desig... more In this work, we propose a novel approach called “Normalized Gain Function (NGF) method” to design low/medium power single stage ultra wide band microwave amplifiers based on linear S parameters of the active device. Normalized Gain Function TNGF is defined as the ratio of T and |S21|, desired shape or frequency response of the gain function of the amplifier to be designed and the shape of the transistor forward gain function, respectively. Synthesis of input/output matching networks (IMN/OMN) of the amplifier requires mathematically generated target gain functions to be tracked in two different nonlinear optimization processes. In this manner, NGF not only facilitates a mathematical base to share the amplifier gain function into such two distinct target gain functions, but also allows their precise computation in terms of TNGF=T/|S21| at the very beginning of the design. The particular amplifier presented as the design example operates over 800-5200 MHz to target GSM, UMTS, Wi-Fi a...
Journal of Circuits, Systems and Computers
Termination transformation theorem (TTT) proposed in this work transforms a doubly complex termin... more Termination transformation theorem (TTT) proposed in this work transforms a doubly complex terminated microwave power transfer network (PTN) to an equivalent doubly resistively terminated termination transformed network (TTN) which is essentially a filter network. In this work, the transducer power gain (TPG) formula, Tgen, based on S and transmission (ABCD) parameters for the PTN have been restudied from the classical literature. Then, a new TPG formula, Tgen1, based on the newly proposed TTT has been derived using the transformed TTN network. To be able to show the validity of the proposed TTT, the newly derived TPG formula Tgen1 and the classical TPG formula Tgen have been computed within the scope of an example PTN design. The theorem has been proved mathematically, and experimentally as well with the aid of a Matlab code. The performance plots yielded from the Matlab code have clearly shown that both TPG formulae, i.e., Tgen and Tgen1, are in complete agreement with each other....
Balkan Journal of Electrical and Computer Engineering
2016 16th Mediterranean Microwave Symposium (MMS), 2016
2016 39th International Conference on Telecommunications and Signal Processing (TSP), 2016
2016 39th International Conference on Telecommunications and Signal Processing (TSP), 2016
IEEE Transactions on Circuits and Systems II: Express Briefs, 2016
2015 2nd International Conference on Knowledge-Based Engineering and Innovation (KBEI), 2015
2014 IEEE Benjamin Franklin Symposium on Microwave and Antenna Sub-systems for Radar, Telecommunications, and Biomedical Applications (BenMAS), 2014
A broadband matching network design is given with its simulation and prototype measurement result... more A broadband matching network design is given with its simulation and prototype measurement results. The circuit contains certain number of cascaded unit-elements (UEs) and open-stubs which behave as Richards capacitors. Richards domain driving point immittance (impedance or admittance) function of the network is obtained utilizing the Real Frequency Direct Computational Technique (RFDCT). Synthesis of the immittance function via "high precision Richards synthesis package" yields the characteristic impedances of microstrip unit-elements, open and short stubs. Kuroda transforms are used to convert short-stubs to openstubs due to their difficulties in manufacturing. Theoretical design, simulation and measurements are in a good agreement. Index Terms-Impedance matching, Richards domain, network synthesis, double matching problem, real frequency techniques.
2014 IEEE Benjamin Franklin Symposium on Microwave and Antenna Sub-systems for Radar, Telecommunications, and Biomedical Applications (BenMAS), 2014
In this work, we introduce the design and implementation of wideband microwave amplifiers based o... more In this work, we introduce the design and implementation of wideband microwave amplifiers based on "Normalized Gain Function (NGF)" method. Normalized Gain Function is defined as the ratio of desired shape or frequency response of the gain function of the amplifier to be designed and shape of the transistor forward gain function. Synthesis of input/output matching networks (IMN/OMN) of the amplifier require target gain curves as the functions of normalized gain function to be tracked in two sequential nonlinear optimization processes. A prototype low power amplifier circuit is produced and measured to show the usability of the design approach.
2014 IEEE Benjamin Franklin Symposium on Microwave and Antenna Sub-systems for Radar, Telecommunications, and Biomedical Applications (BenMAS), 2014
In this work, we introduce a high precision synthesis algorithm to include the extraction of fini... more In this work, we introduce a high precision synthesis algorithm to include the extraction of finite frequency and right half plane (RHP) transmission zeros of an impedance function as Brune/Darlington Type-C sections. After each transmission zero extraction, remaining immittance function is corrected using a parametric approach. It is shown that proposed high precision synthesis algorithm can synthesize immittance functions up to 40 reactive elements with accumulated relative error in the order of 10-1. The high precision synthesis package is integrated with the real frequency techniques to design matching networks over broadbands. Examples are presented to exhibit the usage of the proposed high precision synthesis algorithm.
In order to maximize efficiency of the designed gyrator-based active inductor, advanced circuit t... more In order to maximize efficiency of the designed gyrator-based active inductor, advanced circuit techniques are used. Loss and noise are most important features of the AIs, where they should be low enough to have high-performance device. The gyrator-C topology is used to design a new low-loss and low-noise active inductor. The gyrator-C topology is potentially high-Q and all transistors are utilized in common-source configuration to have high impedance in input-output nodes. All transistors are free of body effect. The p-type differential pair input transistors and the feed forward path are employed to decrease noise of the proposed circuit. Additionally, inductance value and quality factor are adjusted by variation bias current which gives to the device tunable capability. HSPICE simulation results are presented to verify the performance of the circuit, where the 180 nm CMOS process and 1.8 V power supply are used. The noise voltage and power dissipation are less than 2.8 nV/ √ Hz and 1.3 mW, respectively.
Circuits Systems and Signal Processing, Sep 8, 2017
An accurate CMOS interface small capacitance variation sensing circuit for capacitive MEMS sensor... more An accurate CMOS interface small capacitance variation sensing circuit for capacitive MEMS sensor applications An accurate front-end CMOS interface circuit for sensing very small capacitance changes in capacitive sensors is presented in this paper. The proposed structure scales capacitance variation to the sensible impedance changing. The scaling factor of the circuit can be easily tuned by adjusting bias points of the transistors. In order to cancel or decrease the parasitic components, the RC feedback and input transistor cascading techniques are used in the design. To simulate the circuit, HSPICE simulator is utilized to verify the validity of the theoretical formulations in 0.18 µm technology. According to schematic and post layout simulation results input impedance changes linearly versus capacitance variations up to 0.7 GHz while the sensor capacitance changing is varied between 0~200fF. Total dc power consumption is obtained as low as 1.2 mW with 1.8 V power supply.
Analog Integrated Circuits and Signal Processing, Jun 2, 2016
In this paper, a 50 X terminated or in other words transformerless bandpass matching network desi... more In this paper, a 50 X terminated or in other words transformerless bandpass matching network design methodology and an implementation example are presented. The real frequency techniques are powerful numerical methods to design wideband lossless two-port networks such as filters, matching networks and amplifiers. In these techniques, the value of the termination resistance of the designed network could not be yielded as 50 X by numerical package. Hence, a transformer is also required for 50 X termination which is not practical for high frequency applications. By employing the proposed procedure, it is guaranteed to obtain transformerless bandpass matching network. Also in this study a wideband suspended monopole antenna is examined. The proposed antenna consists of two major elements; Y-shaped impedance matching plate and hemi-circular radiator. Moreover Y-shaped impedance matching plate connected to a feeding probe excites the suspended hemi-circular radiator via air gap. Consequently, a transformerless bandpass matching network is designed to filter and expand the operational frequency bandwidth of the proposed antenna. It has been observed that ideal circuit and the layout of the matching network simulation have good agreement.
Integration, 2017
This work presents a new low-loss active inductor whose self-resonance frequency and quality fact... more This work presents a new low-loss active inductor whose self-resonance frequency and quality factor parameters can be adjusted independently from each other. In order to achieve this property, a new input topology has been employed which consists of cascode structure with a diode connected transistor. Furthermore, the proposed input topology makes the device robust in terms of its performance over variation in process, voltage and temperature. Additionally, RC feedback is used to cancel series-loss resistance of the active inductor, which allows self-resonant enhancement as well. Schematic and post-layout simulation results show the theoretical validity of the design. To validate the design feasibility for process, voltage and temperature changes, Monte Carlo and temperature analysis are done. Suggested structure shows inductor behavior in the frequency range of 0.3-11.3 GHz. Maximum quality factor is obtained as high as 2.1k at 5.9 GHz. Total power consumption is as low as 1mW with 1.8 V power supply.
2016 National Conference on Electrical, Electronics and Biomedical Engineering (ELECO), 2016
Nowadays design of communication instruments that use for communication show a great improvement ... more Nowadays design of communication instruments that use for communication show a great improvement and change. Communication instruments consist of many systems. At this study, microwave amplifier design that has a great important as system carry out for supply communication. Microwave amplifier design carry out for cellular communication in the range of 0.8–1.9 GHz bandwith. Amplifier circuit design by using ADS program. Amplifier circuit consist of ideal circuit, microstrip circuit, layout circuit and circuit production. At this study, results of production of acquired design resemble to results of program design.
2019 International Conference on Power Generation Systems and Renewable Energy Technologies (PGSRET)
Design and simulation of a microwave wideband microstrip unit element bandpass matching network i... more Design and simulation of a microwave wideband microstrip unit element bandpass matching network is presented, potential use might be a broadband WPT (microwave wireless power transfer) application in X-band frequencies (8-12 GHz). The source of the main energy can be wind, fossil, tidal, solar, nuclear, hydro etc. and the main energy can be converted from DC to microwave energy which then can be transmitted via the proposed WPT circuit towards a few or a network of a multiple microwave harvester receivers located at a near or far field from the main source. In the work, a bandpass matching network (BPMN) composed of microstrip "unit elements (UEs)" is designed to operate along the whole X-band (8-12 GHz). Designed BPMN is excited by an X-band commercial PA (power amplifier) MMIC (monolithic microwave integrated circuit) packaged chip, and it is loaded by an X-band microstrip patch antenna. A bond wire soldered between the RF output pad of MMIC chip and the input pad of the BPMN has an equivalent LC parasitic impedance assumed to be the generator complex impedance that must be compensated in a typical matching problem. SRFT (simplified real frequency technique) is used in the design of the matching network that compensates the effect of bond wire and very good agreement found between the theoretical design and simulations done in MWO (AWR).
Istanbul University - Journal of Electrical and Electronics Engineering, 2016
This work is the continuation of our high precision immittance synthesis paper series introduced ... more This work is the continuation of our high precision immittance synthesis paper series introduced in IEEE TCAS-I. In the present manuscript, we modified the previously introduced high precision Bandpass LC-ladder synthesis algorithm to include the extraction of finite frequency and right half plane (RHP) transmission zeros of an impedance function as Brune/Darlington Type-C sections. Finite frequency and RHP transmission zeros are extracted employing our newly introduced modified impedance and chain parameters based algorithms one by one. After each transmission zero extraction, remaining immittance function is corrected using parametric approach. It is shown that propsed high precision synthesis algorithms can synthesize immittance functions up to 40 reactive elements with accumulated relative error in the order of 10 - 1 . The modified high precision synthesis package is developed in MatLab environment and it is integrated with the real frequency techniques to design matching netwo...
International Journal of Electronics Letters, 2016
An accurate CMOS interface small capacitance variation sensing circuit for capacitive MEMS sensor... more An accurate CMOS interface small capacitance variation sensing circuit for capacitive MEMS sensor applications An accurate front-end CMOS interface circuit for sensing very small capacitance changes in capacitive sensors is presented in this paper. The proposed structure scales capacitance variation to the sensible impedance changing. The scaling factor of the circuit can be easily tuned by adjusting bias points of the transistors. In order to cancel or decrease the parasitic components, the RC feedback and input transistor cascading techniques are used in the design. To simulate the circuit, HSPICE simulator is utilized to verify the validity of the theoretical formulations in 0.18 µm technology. According to schematic and post layout simulation results input impedance changes linearly versus capacitance variations up to 0.7 GHz while the sensor capacitance changing is varied between 0~200fF. Total dc power consumption is obtained as low as 1.2 mW with 1.8 V power supply.
In this work, we propose a novel approach called “Normalized Gain Function (NGF) method” to desig... more In this work, we propose a novel approach called “Normalized Gain Function (NGF) method” to design low/medium power single stage ultra wide band microwave amplifiers based on linear S parameters of the active device. Normalized Gain Function TNGF is defined as the ratio of T and |S21|, desired shape or frequency response of the gain function of the amplifier to be designed and the shape of the transistor forward gain function, respectively. Synthesis of input/output matching networks (IMN/OMN) of the amplifier requires mathematically generated target gain functions to be tracked in two different nonlinear optimization processes. In this manner, NGF not only facilitates a mathematical base to share the amplifier gain function into such two distinct target gain functions, but also allows their precise computation in terms of TNGF=T/|S21| at the very beginning of the design. The particular amplifier presented as the design example operates over 800-5200 MHz to target GSM, UMTS, Wi-Fi a...
Journal of Circuits, Systems and Computers
Termination transformation theorem (TTT) proposed in this work transforms a doubly complex termin... more Termination transformation theorem (TTT) proposed in this work transforms a doubly complex terminated microwave power transfer network (PTN) to an equivalent doubly resistively terminated termination transformed network (TTN) which is essentially a filter network. In this work, the transducer power gain (TPG) formula, Tgen, based on S and transmission (ABCD) parameters for the PTN have been restudied from the classical literature. Then, a new TPG formula, Tgen1, based on the newly proposed TTT has been derived using the transformed TTN network. To be able to show the validity of the proposed TTT, the newly derived TPG formula Tgen1 and the classical TPG formula Tgen have been computed within the scope of an example PTN design. The theorem has been proved mathematically, and experimentally as well with the aid of a Matlab code. The performance plots yielded from the Matlab code have clearly shown that both TPG formulae, i.e., Tgen and Tgen1, are in complete agreement with each other....
Balkan Journal of Electrical and Computer Engineering
2016 16th Mediterranean Microwave Symposium (MMS), 2016
2016 39th International Conference on Telecommunications and Signal Processing (TSP), 2016
2016 39th International Conference on Telecommunications and Signal Processing (TSP), 2016
IEEE Transactions on Circuits and Systems II: Express Briefs, 2016
2015 2nd International Conference on Knowledge-Based Engineering and Innovation (KBEI), 2015
2014 IEEE Benjamin Franklin Symposium on Microwave and Antenna Sub-systems for Radar, Telecommunications, and Biomedical Applications (BenMAS), 2014
A broadband matching network design is given with its simulation and prototype measurement result... more A broadband matching network design is given with its simulation and prototype measurement results. The circuit contains certain number of cascaded unit-elements (UEs) and open-stubs which behave as Richards capacitors. Richards domain driving point immittance (impedance or admittance) function of the network is obtained utilizing the Real Frequency Direct Computational Technique (RFDCT). Synthesis of the immittance function via "high precision Richards synthesis package" yields the characteristic impedances of microstrip unit-elements, open and short stubs. Kuroda transforms are used to convert short-stubs to openstubs due to their difficulties in manufacturing. Theoretical design, simulation and measurements are in a good agreement. Index Terms-Impedance matching, Richards domain, network synthesis, double matching problem, real frequency techniques.
2014 IEEE Benjamin Franklin Symposium on Microwave and Antenna Sub-systems for Radar, Telecommunications, and Biomedical Applications (BenMAS), 2014
In this work, we introduce the design and implementation of wideband microwave amplifiers based o... more In this work, we introduce the design and implementation of wideband microwave amplifiers based on "Normalized Gain Function (NGF)" method. Normalized Gain Function is defined as the ratio of desired shape or frequency response of the gain function of the amplifier to be designed and shape of the transistor forward gain function. Synthesis of input/output matching networks (IMN/OMN) of the amplifier require target gain curves as the functions of normalized gain function to be tracked in two sequential nonlinear optimization processes. A prototype low power amplifier circuit is produced and measured to show the usability of the design approach.
2014 IEEE Benjamin Franklin Symposium on Microwave and Antenna Sub-systems for Radar, Telecommunications, and Biomedical Applications (BenMAS), 2014
In this work, we introduce a high precision synthesis algorithm to include the extraction of fini... more In this work, we introduce a high precision synthesis algorithm to include the extraction of finite frequency and right half plane (RHP) transmission zeros of an impedance function as Brune/Darlington Type-C sections. After each transmission zero extraction, remaining immittance function is corrected using a parametric approach. It is shown that proposed high precision synthesis algorithm can synthesize immittance functions up to 40 reactive elements with accumulated relative error in the order of 10-1. The high precision synthesis package is integrated with the real frequency techniques to design matching networks over broadbands. Examples are presented to exhibit the usage of the proposed high precision synthesis algorithm.