Kumarasamy Raja - Academia.edu (original) (raw)
Papers by Kumarasamy Raja
IEEE Transactions on Circuits and Systems Ii-express Briefs, 2023
In this paper, an equivalent three port scalable Inductor model has been developed for symmetric ... more In this paper, an equivalent three port scalable Inductor model has been developed for symmetric octagonal spiral inductors. The scalable inductor model is able to achieve good match for two port with center-tap connected to ground, three port differential and three port single-ended structures. Adjustable parameters include the number of turns (N), inner diameter (D), width (W) and spacing (S) of inductors. The model is verified to match well with simulation and measurement results.
Abstract An ultra-low-power 401406 MHz Medical Device Radiocommunication Service (MedRadio) rece... more Abstract An ultra-low-power 401406 MHz Medical Device Radiocommunication Service (MedRadio) receiver RF front-end for biomédical telemetry applications is implemented using 0.18-μm CMOS technology with a 1-V supply voltage. The receiver RF front-end ...
This work describes a CMOS RF power detector with an extremely low temperature drift, less than ±... more This work describes a CMOS RF power detector with an extremely low temperature drift, less than ± 0.5 dB in a wide temperature range, from - 40°C to 125°C. The power detector is based on a biased diode detector with a load resistance, and it is implemented in 55-nm technology which shows a wide dynamic range of 24 dBm over a large operating frequency, from 1 GHz to 14 GHz.
International journal of information and electronics engineering, 2013
IEEE solid-state circuits letters, 2022
Sensors
While the active ultrasonic method is an attractive structural health monitoring (SHM) technology... more While the active ultrasonic method is an attractive structural health monitoring (SHM) technology, many practical issues such as weight of transducers and cables, energy consumption, reliability and cost of implementation are restraining its application. To overcome these challenges, an active ultrasonic SHM technology enabled by a direct-write transducer (DWT) array and edge computing process is proposed in this work. The operation feasibility of the monitoring function is demonstrated with Lamb wave excited and detected by a linear DWT array fabricated in situ from piezoelectric P(VDF-TrFE) polymer coating on an aluminum alloy plate with a simulated defect. The DWT array features lightweight, small profile, high conformability, and implementation scalability, whilst the edge-computing circuit dedicatedly designed for the active ultrasonic SHM is able to perform signal processing at the sensor nodes before wirelessly transmitting the data to a remote host device. The successful imp...
2020 IEEE Asia-Pacific Microwave Conference (APMC), 2020
This paper presents a 19 to 20. 25GHz transformer based VCO with a 4X frequency multiplier that i... more This paper presents a 19 to 20. 25GHz transformer based VCO with a 4X frequency multiplier that is used to generate 76 to 81GHz FMCW radar chirp signal in ADAS car applications. In order to distinguish between two closely spaced objects or a slowly moving object and a static target, phase noise requirements are stringent. Post layout and Electromagnetic simulations show that the phase noise at the frequency of20GHz of the VCO is -103dBc/Hz with frequency offsets of 1MHz in 40nm CMOS process owing to the proposed noise-reduction circuit techniques. The total die area of the proposed VCO and multiplier is 0.3mmX 1mm. The current consumption of the VCO and 4X frequency multiplier are 10mA and 35mA with 1.1V supply voltage.
2012 IEEE International Symposium on Radio-Frequency Integration Technology (RFIT), 2012
ABSTRACT
2014 International Symposium on Integrated Circuits (ISIC), 2014
In this paper, an equivalent three port scalable Inductor model has been developed for symmetric ... more In this paper, an equivalent three port scalable Inductor model has been developed for symmetric octagonal spiral inductors. The scalable inductor model is able to achieve good match for two port with center-tap connected to ground, three port differential and three port single-ended structures. Adjustable parameters include the number of turns (N), inner diameter (D), width (W) and spacing (S) of inductors. The model is verified to match well with simulation and measurement results.
International Journal of Computer and Electrical Engineering, 2012
This paper presents an analog baseband block for a packaged 76-81 GHz transceiver chip implemente... more This paper presents an analog baseband block for a packaged 76-81 GHz transceiver chip implemented in 40 nm pure-CMOS for both long and short ranges frequency modulated continuous wave (FMCW) automotive radar. The transceiver consist of four-channels receiver and the analog baseband in each channel comprises of 4th order active-RC based Butterworth low-pass filter cascaded with fixed and programmable gain amplifiers (PGA) to achieve the required maximum gain and gain variation. The filter implements tunability in the bandwidth between 10M and 15 MHz and provides a fixed gain of 10 dB. The resistor divider based PGA provides 26 dB configurable gain using digital control bits with 2 dB step-size. The receiver baseband chain has a pass-band flatness with in-band ripple less than 1-dB, and a maximum gain of 50 dB. The DC offset cancellation (DCOC) implemented provides tunability in the high-pass low-frequency cut-off for effective power leakage rejection from the transmitter to the receiver chain. The in-band output P1dB of > 14 dBm and an out-of-band OP1dB of > 7 dBm with a noise-figure of < 18 dB ensures good linearity and SNR in line with current industrial standard.
A hybrid approach of the DC-DC conversion is presented for battery-operated portable electronics ... more A hybrid approach of the DC-DC conversion is presented for battery-operated portable electronics systems such as wearable health monitoring devices. A switched-capacitor (SC) DC-DC converter is steered by hysteretic control to provide buck-boost conversion with a flexible conversion ratio, and its output is regulated by a low-drop-out (LDO) regulator delivering a low-ripple DC output. The SC DC-DC converter consists of only 4 switches and 2 capacitors, and employs a combination of NMOS and PMOS transistors simplifying the gate drive scheme. The converter has been designed to work up to 30MHz switching frequency and provides 2.8V output from a battery supply varying from 3.5 to 2V over its discharge cycle. It has been fabricated in 0.18μm CMOS technology.
2014 International Symposium on Integrated Circuits (ISIC), 2014
A multi-function multi-mode baseband design for low data-rate applications is proposed in this pa... more A multi-function multi-mode baseband design for low data-rate applications is proposed in this paper. The baseband is integrated with RF TX/RX module to provide a complete transceiver. A low-power synchronization scheme is proposed in this paper. Automatic Frequency Control is also introduced into the baseband design. The baseband is designed and fabricated in 0.13μm CMOS process with total area of 0.6 mm2 (including AFC). The maximum power is 1.65 mW at 1.2V supply.
2011 IEEE International 3D Systems Integration Conference (3DIC), 2011 IEEE International, 2012
In this paper, an innovative design of a miniaturized heterogeneous 3DIC-based wireless sensor no... more In this paper, an innovative design of a miniaturized heterogeneous 3DIC-based wireless sensor node (WSN) is proposed. The design contains stacks of radio frequency (RF) die, mixed-signal die, digital die, and integrated antenna die using the through silicon via (TSV) technology. Significant enhancements to the existing 2D design and verification flow are developed to solve the critical concerns of heterogeneous 3DIC integration, including the block-level partitioning, TSV macro design, the TSV-related modeling and characterization, and physical verification. Solutions are proposed to minimize the electromagnetic interference (EMI) effects between the IC and the antenna. The size of the proposed 3DIC is only 66% as compared to a similar 2D implementation, permitting miniaturization of the complete WSN system.
An envelope generation circuit which generates the top and bottom envelope for PR-ASK, SSB-ASK an... more An envelope generation circuit which generates the top and bottom envelope for PR-ASK, SSB-ASK and DSB-ASK with modulation depths (m) from 10% to 100% with steps of 10% for use in EPC and ISO compliant RFID reader is described. It employs a VTH independent level shifter biased with a VTH tracking circuit so that the change in VTH due to process variation does not distort m. The highest level shifter error is 7% under extreme PVT when the VTH varies by 63%. Measured results include a modulation depth accuracy of 2%, modulation steps of 10% under supply and temperature extremes.
2021 IEEE Asia-Pacific Microwave Conference (APMC)
Asset tracking is important in managing shared resources in factory, office and other environment... more Asset tracking is important in managing shared resources in factory, office and other environments. Often times these shared assets are not returned to their intended place of storage after use, leading to inefficient use of these resources. In order to address this, we have developed a ZigBee system with wirelessly powered ZigBee sensor node that can track the location of the assets and send the location information periodically back to the server. This makes the location of these assets available in a central server, to enable these assets be deployed efficiently. This paper presents the design of a wireless powered ZigBee 3.0 sensor node which is capable of transmitting asset location periodically to the server solely from harvested RF energy from the router with an on board super capacitor as energy reservoir. This avoids the need for battery powering of the sensor node and periodic maintenance required due to the use of battery. It also presents a design of ZigBee 3.0 router with built in sub 1 GHz RF power transmitter with up to 33 dBm transmit power to enable wireless powering of sensor node.
2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI), 2021
Phased array technique is essential for beam-forming and beam-steering in mmWave applications lik... more Phased array technique is essential for beam-forming and beam-steering in mmWave applications like radar, imaging and 5G. Beam squinting in a phased array is one of the limiting factors to support wide bandwidth operation. This paper discusses the impact of phase shifter design choices on beam squinting in the phased array. Although true time delay circuits can circumvent beam squinting, it becomes impossible when the array size becomes larger as the large slope of phase versus frequency within the bandwidth crosses 360 degrees (1 carrier cycle). A look-up table based reconfigurable phase shifter is proposed to reduce the beam squinting over a large bandwidth and the method is validated by extensive phased array simulation.
In this paper, the design of wide-swing constant transconductance (<i>g<sub>m</sub... more In this paper, the design of wide-swing constant transconductance (<i>g<sub>m</sub></i>) bias circuit that generates bias voltage for low-noise amplifier (LNA) circuit design by using an off-chip resistor is demonstrated. The overall transconductance (<i>G<sub>m</sub></i>) generated by the constant <i>g<sub>m</sub></i> bias circuit is important to maintain the overall gain and noise figure of the LNA circuit. Therefore, investigation is performed to study the variation in <i>G<sub>m</sub></i> with process, temperature and supply voltage (PVT). Temperature and supply voltage are swept from -10 °C to 85 °C and 1.425 V to 1.575 V respectively, while the process conditions are also varied to the extreme and the <i>g<sub>m</sub></i> variation is eventually concluded at between -3 % to 7 %. With the slight variation in the<i> g<sub>m</sub></i> val...
IEEE Transactions on Circuits and Systems Ii-express Briefs, 2023
In this paper, an equivalent three port scalable Inductor model has been developed for symmetric ... more In this paper, an equivalent three port scalable Inductor model has been developed for symmetric octagonal spiral inductors. The scalable inductor model is able to achieve good match for two port with center-tap connected to ground, three port differential and three port single-ended structures. Adjustable parameters include the number of turns (N), inner diameter (D), width (W) and spacing (S) of inductors. The model is verified to match well with simulation and measurement results.
Abstract An ultra-low-power 401406 MHz Medical Device Radiocommunication Service (MedRadio) rece... more Abstract An ultra-low-power 401406 MHz Medical Device Radiocommunication Service (MedRadio) receiver RF front-end for biomédical telemetry applications is implemented using 0.18-μm CMOS technology with a 1-V supply voltage. The receiver RF front-end ...
This work describes a CMOS RF power detector with an extremely low temperature drift, less than ±... more This work describes a CMOS RF power detector with an extremely low temperature drift, less than ± 0.5 dB in a wide temperature range, from - 40°C to 125°C. The power detector is based on a biased diode detector with a load resistance, and it is implemented in 55-nm technology which shows a wide dynamic range of 24 dBm over a large operating frequency, from 1 GHz to 14 GHz.
International journal of information and electronics engineering, 2013
IEEE solid-state circuits letters, 2022
Sensors
While the active ultrasonic method is an attractive structural health monitoring (SHM) technology... more While the active ultrasonic method is an attractive structural health monitoring (SHM) technology, many practical issues such as weight of transducers and cables, energy consumption, reliability and cost of implementation are restraining its application. To overcome these challenges, an active ultrasonic SHM technology enabled by a direct-write transducer (DWT) array and edge computing process is proposed in this work. The operation feasibility of the monitoring function is demonstrated with Lamb wave excited and detected by a linear DWT array fabricated in situ from piezoelectric P(VDF-TrFE) polymer coating on an aluminum alloy plate with a simulated defect. The DWT array features lightweight, small profile, high conformability, and implementation scalability, whilst the edge-computing circuit dedicatedly designed for the active ultrasonic SHM is able to perform signal processing at the sensor nodes before wirelessly transmitting the data to a remote host device. The successful imp...
2020 IEEE Asia-Pacific Microwave Conference (APMC), 2020
This paper presents a 19 to 20. 25GHz transformer based VCO with a 4X frequency multiplier that i... more This paper presents a 19 to 20. 25GHz transformer based VCO with a 4X frequency multiplier that is used to generate 76 to 81GHz FMCW radar chirp signal in ADAS car applications. In order to distinguish between two closely spaced objects or a slowly moving object and a static target, phase noise requirements are stringent. Post layout and Electromagnetic simulations show that the phase noise at the frequency of20GHz of the VCO is -103dBc/Hz with frequency offsets of 1MHz in 40nm CMOS process owing to the proposed noise-reduction circuit techniques. The total die area of the proposed VCO and multiplier is 0.3mmX 1mm. The current consumption of the VCO and 4X frequency multiplier are 10mA and 35mA with 1.1V supply voltage.
2012 IEEE International Symposium on Radio-Frequency Integration Technology (RFIT), 2012
ABSTRACT
2014 International Symposium on Integrated Circuits (ISIC), 2014
In this paper, an equivalent three port scalable Inductor model has been developed for symmetric ... more In this paper, an equivalent three port scalable Inductor model has been developed for symmetric octagonal spiral inductors. The scalable inductor model is able to achieve good match for two port with center-tap connected to ground, three port differential and three port single-ended structures. Adjustable parameters include the number of turns (N), inner diameter (D), width (W) and spacing (S) of inductors. The model is verified to match well with simulation and measurement results.
International Journal of Computer and Electrical Engineering, 2012
This paper presents an analog baseband block for a packaged 76-81 GHz transceiver chip implemente... more This paper presents an analog baseband block for a packaged 76-81 GHz transceiver chip implemented in 40 nm pure-CMOS for both long and short ranges frequency modulated continuous wave (FMCW) automotive radar. The transceiver consist of four-channels receiver and the analog baseband in each channel comprises of 4th order active-RC based Butterworth low-pass filter cascaded with fixed and programmable gain amplifiers (PGA) to achieve the required maximum gain and gain variation. The filter implements tunability in the bandwidth between 10M and 15 MHz and provides a fixed gain of 10 dB. The resistor divider based PGA provides 26 dB configurable gain using digital control bits with 2 dB step-size. The receiver baseband chain has a pass-band flatness with in-band ripple less than 1-dB, and a maximum gain of 50 dB. The DC offset cancellation (DCOC) implemented provides tunability in the high-pass low-frequency cut-off for effective power leakage rejection from the transmitter to the receiver chain. The in-band output P1dB of > 14 dBm and an out-of-band OP1dB of > 7 dBm with a noise-figure of < 18 dB ensures good linearity and SNR in line with current industrial standard.
A hybrid approach of the DC-DC conversion is presented for battery-operated portable electronics ... more A hybrid approach of the DC-DC conversion is presented for battery-operated portable electronics systems such as wearable health monitoring devices. A switched-capacitor (SC) DC-DC converter is steered by hysteretic control to provide buck-boost conversion with a flexible conversion ratio, and its output is regulated by a low-drop-out (LDO) regulator delivering a low-ripple DC output. The SC DC-DC converter consists of only 4 switches and 2 capacitors, and employs a combination of NMOS and PMOS transistors simplifying the gate drive scheme. The converter has been designed to work up to 30MHz switching frequency and provides 2.8V output from a battery supply varying from 3.5 to 2V over its discharge cycle. It has been fabricated in 0.18μm CMOS technology.
2014 International Symposium on Integrated Circuits (ISIC), 2014
A multi-function multi-mode baseband design for low data-rate applications is proposed in this pa... more A multi-function multi-mode baseband design for low data-rate applications is proposed in this paper. The baseband is integrated with RF TX/RX module to provide a complete transceiver. A low-power synchronization scheme is proposed in this paper. Automatic Frequency Control is also introduced into the baseband design. The baseband is designed and fabricated in 0.13μm CMOS process with total area of 0.6 mm2 (including AFC). The maximum power is 1.65 mW at 1.2V supply.
2011 IEEE International 3D Systems Integration Conference (3DIC), 2011 IEEE International, 2012
In this paper, an innovative design of a miniaturized heterogeneous 3DIC-based wireless sensor no... more In this paper, an innovative design of a miniaturized heterogeneous 3DIC-based wireless sensor node (WSN) is proposed. The design contains stacks of radio frequency (RF) die, mixed-signal die, digital die, and integrated antenna die using the through silicon via (TSV) technology. Significant enhancements to the existing 2D design and verification flow are developed to solve the critical concerns of heterogeneous 3DIC integration, including the block-level partitioning, TSV macro design, the TSV-related modeling and characterization, and physical verification. Solutions are proposed to minimize the electromagnetic interference (EMI) effects between the IC and the antenna. The size of the proposed 3DIC is only 66% as compared to a similar 2D implementation, permitting miniaturization of the complete WSN system.
An envelope generation circuit which generates the top and bottom envelope for PR-ASK, SSB-ASK an... more An envelope generation circuit which generates the top and bottom envelope for PR-ASK, SSB-ASK and DSB-ASK with modulation depths (m) from 10% to 100% with steps of 10% for use in EPC and ISO compliant RFID reader is described. It employs a VTH independent level shifter biased with a VTH tracking circuit so that the change in VTH due to process variation does not distort m. The highest level shifter error is 7% under extreme PVT when the VTH varies by 63%. Measured results include a modulation depth accuracy of 2%, modulation steps of 10% under supply and temperature extremes.
2021 IEEE Asia-Pacific Microwave Conference (APMC)
Asset tracking is important in managing shared resources in factory, office and other environment... more Asset tracking is important in managing shared resources in factory, office and other environments. Often times these shared assets are not returned to their intended place of storage after use, leading to inefficient use of these resources. In order to address this, we have developed a ZigBee system with wirelessly powered ZigBee sensor node that can track the location of the assets and send the location information periodically back to the server. This makes the location of these assets available in a central server, to enable these assets be deployed efficiently. This paper presents the design of a wireless powered ZigBee 3.0 sensor node which is capable of transmitting asset location periodically to the server solely from harvested RF energy from the router with an on board super capacitor as energy reservoir. This avoids the need for battery powering of the sensor node and periodic maintenance required due to the use of battery. It also presents a design of ZigBee 3.0 router with built in sub 1 GHz RF power transmitter with up to 33 dBm transmit power to enable wireless powering of sensor node.
2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI), 2021
Phased array technique is essential for beam-forming and beam-steering in mmWave applications lik... more Phased array technique is essential for beam-forming and beam-steering in mmWave applications like radar, imaging and 5G. Beam squinting in a phased array is one of the limiting factors to support wide bandwidth operation. This paper discusses the impact of phase shifter design choices on beam squinting in the phased array. Although true time delay circuits can circumvent beam squinting, it becomes impossible when the array size becomes larger as the large slope of phase versus frequency within the bandwidth crosses 360 degrees (1 carrier cycle). A look-up table based reconfigurable phase shifter is proposed to reduce the beam squinting over a large bandwidth and the method is validated by extensive phased array simulation.
In this paper, the design of wide-swing constant transconductance (<i>g<sub>m</sub... more In this paper, the design of wide-swing constant transconductance (<i>g<sub>m</sub></i>) bias circuit that generates bias voltage for low-noise amplifier (LNA) circuit design by using an off-chip resistor is demonstrated. The overall transconductance (<i>G<sub>m</sub></i>) generated by the constant <i>g<sub>m</sub></i> bias circuit is important to maintain the overall gain and noise figure of the LNA circuit. Therefore, investigation is performed to study the variation in <i>G<sub>m</sub></i> with process, temperature and supply voltage (PVT). Temperature and supply voltage are swept from -10 °C to 85 °C and 1.425 V to 1.575 V respectively, while the process conditions are also varied to the extreme and the <i>g<sub>m</sub></i> variation is eventually concluded at between -3 % to 7 %. With the slight variation in the<i> g<sub>m</sub></i> val...