Jie-Wei Lai - Academia.edu (original) (raw)

Papers by Jie-Wei Lai

Research paper thumbnail of Output Beam Quality Improvement using a Narrow Input for Tapered Semiconductor Laser amplifiers

Conference on Lasers and Electro-Optics-Europe

Coherent high-power semiconductor lasers are important for many applications due to their compact... more Coherent high-power semiconductor lasers are important for many applications due to their compactness, low-cost, and possible integration with other photonic devices. Several types of semiconductor laser amplifiers have been proposed to increase the output power. Among them, the tapered semiconductor laser amplifier has demonstrated the highest output power and still has a good beam quality [1]. However, filamentation is still formed when the device is operated at a much higher power level. In the tapered amplifier, the linearly tailored gain region serves as the spherical expansion of the wave front. The expansion is not ideal because it does not start from a point source, which unfortunately does not practically exist. We propose that the input aperture with its size close to the wavelength could work like a point source and so significantly improves the output beam quality.

Research paper thumbnail of Opportunity and Challenge of Chiplet-Based HPC and AIoT

2021 International Symposium on VLSI Design, Automation and Test (VLSI-DAT), 2021

High-performance computing and AI tremendously drive technology innovations on architecture, algo... more High-performance computing and AI tremendously drive technology innovations on architecture, algorithm, memory, and semiconductor design, and continuously impact many fields from computation-intensive applications such as advanced driver-assistance system (ADAS) to highly-heterogeneous integrated, while performance-sensitive systems like 5G mobile and AIoT. Chiplet concept is considered a promising approach to alleviate the pressure on performance, power, cost, yield, and time to market raising with the increasing complexity of the fore-mentioned technologies. In this paper, we like to discuss the challenges and opportunities to satisfy these demands in conjunction with chiplet techniques.

Research paper thumbnail of Large Signal HBT Model and Integrated Circuit Design Using 300-Ghz Indium Phosphide HBT Technology

103 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005.This work describes a mode... more 103 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005.This work describes a modeling approach including the nonlinear effects in the base-collector region covering current blocking, velocity modulation and self-heating. Model is verified in terms of single devices and integrated circuits. Good fitting to the measured DC and high-frequency data from single HBTs is achieved. In terms of circuit verification, high-gain and wideband variable gain amplifier (VGA) is developed using a negative-RE approach. This circuit shows a single-ended S21 of 18 dB and a 3-dB bandwidth of 50 GHz, producing a gain-bandwidth product of 397 GHz which is over two times of the value measured from the VGA designed by conventional method in the same process. Linearity is measured, and the model developed in this work shows the best prediction, which indicates that the nonlinear mechanisms inherent in InP/InGaAs DHBTs cannot be neglected. More design examples are provided with technology considerations, giving a complete discussion of designing very high-frequency circuits.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Research paper thumbnail of Improved output beam quality using new-type flared semiconductor laser amplifiers

Technical Digest. Summaries of Papers Presented at the Conference on Lasers and Electro-Optics. Conference Edition. 1998 Technical Digest Series, Vol.6 (IEEE Cat. No.98CH36178), 1998

Time (ns) CTuM4 Fig. 3. A fragment of the pulse of p-Ge laser with a silicon spacer in the cavity... more Time (ns) CTuM4 Fig. 3. A fragment of the pulse of p-Ge laser with a silicon spacer in the cavity. B = 0.44 T, E = 0.57 kV/cm.

Research paper thumbnail of mm-Wave power-combining architectures

RF and mm-Wave Power Generation in Silicon, 2016

Abstract In this chapter, transformer-based hybrid power-combining in millimeter-wave power ampli... more Abstract In this chapter, transformer-based hybrid power-combining in millimeter-wave power amplifier design will be introduced. The discussion starts with conventional power combiners, the limitation of transformer-based voltage combining, and leads to the hybrid combining concepts covering serial-to-parallel and parallel-to-serial architecture.

Research paper thumbnail of Over 500 GHz InP heterojunction bipolar transistors

16th IPRM. 2004 International Conference on Indium Phosphide and Related Materials, 2004.

Page 1. 2004 International Conference on Indium Phoshide and Related Materials Conference Proceed... more Page 1. 2004 International Conference on Indium Phoshide and Related Materials Conference Proceedings 16th IPRM 3 I, May - 4, June 2004 Kagoshima, Japan 9:oo - 9:30 FA1 -1 Over 500 GHz InP Heterojunction Bipolar Transistors Milton Feng, Walid Hafez, Jie-Wei Lai ...

Research paper thumbnail of A silicon-based, all-passive, 60 GHz, 4-element, phased-array beamformer featuring a differential, reflection-type phase shifter

2010 IEEE International Symposium on Phased Array Systems and Technology, 2010

This paper presents an all-passive, 4-element, phased-array beamformer based on a differential, r... more This paper presents an all-passive, 4-element, phased-array beamformer based on a differential, reflectiontype phase shifter (RTPS) operating in the 60GHz band. The RTPS consists of a differential, vertically-coupled, coupledline hybrid and variable, parallel-LC, resonant, reflective loads, both of which enable low-loss millimeter-wave operation. The design considerations for a silicon-based implementation of all the beamformer elements are discussed in detail. In particular, the influence of the different RTPS components on its insertion loss is analyzed. The beamformer IC and a breakout of the RTPS are implemented using CMOS-only features of IBM's 8HP 0.13µm SiGe BiCMOS process, and employ areas of 2.1mm 2 and 0.33mm 2 , respectively, without probe pads. Differential s-parameter measurements at 60GHz show a phase-shift range greater than 150 o , insertion losses of 4-6.2dB in the RTPS and 14-16dB in the beamformer, and an isolation better than 35dB between adjacent beamformer channels. Measurements across temperature and process variations are also presented.

Research paper thumbnail of InP/InGaAs DHBT Large Signal Model for Nonlinearity Harmonic Predictions in ICs

In this work an improved large-signal transistor model is developed especially for InP DHBTs base... more In this work an improved large-signal transistor model is developed especially for InP DHBTs based on Agilent ADS SDD model platform. This model includes the nonlinear effects of current blocking and velocity modulation. The model is verified on Vitesse VIP2 300GHz InP/InGaAs DHBTs and the simulation results of different models are compared with measured results. In addition to the validation

Research paper thumbnail of Analysis of Beam Amplification in Hyperbolically Flared Semiconductor Laser Amplifiers

Proceedings of European Meeting on Lasers and Electro-Optics CLEOE-96, 1996

Research paper thumbnail of Self-aligned InP DHBTs for 150GHz digital and mixed signal circuits

International Conference on Indium Phosphide and Related Materials, 2005.

A production oriented manufacturing process for Indium Phosphide double-heterojunction bipolar tr... more A production oriented manufacturing process for Indium Phosphide double-heterojunction bipolar transistor (DHBT) devices that enables 150 GHz digital and mixed signal circuits is presented. These transistors have cut-off frequency (f) and maximum oscillation frequency (fmax) both over 300 GHz and open-base breakdown voltage (BVceo) over 4 V. Common Mode Logic (CML) ring oscillators have exhibited 1.95 ps gate delay and

Research paper thumbnail of Submicron scaling InP/InGaAs single heterojunction bipolar transistor technology with f/sub T/ > 400 GHz for >100 GHz applications

25th Annual Technical Digest 2003. IEEE Gallium Arsenide Integrated Circuit (GaAs IC) Symposium, 2003., 2003

ABSTRACT

Research paper thumbnail of 300 GHz InP DHBT large signal model including current blocking effect and validated by Gilbert multiplier circuits

IEEE Compound Semiconductor Integrated Circuit Symposium, 2005. CSIC '05., 2005

ABSTRACT

Research paper thumbnail of A 1V 17.9dBm 60GHz power amplifier in standard 65nm CMOS

2010 IEEE International Solid-State Circuits Conference - (ISSCC), 2010

... 23.6 A 1V 17.9dBm 60GHz Power Amplifier in Standard 65nm CMOS Jie-Wei Lai1, AlbertoValdes-Gar... more ... 23.6 A 1V 17.9dBm 60GHz Power Amplifier in Standard 65nm CMOS Jie-Wei Lai1, AlbertoValdes-Garcia2 ... Figure 23.6.7 summarizes the state-of-the-art 60GHz silicon PAs. The proposed 1V VDD CMOS PA compares favorably to the recent results in CMOS [1-4] and SiGe [5]. ...

Research paper thumbnail of A 4-in-1 (WiFi/BT/FM/GPS) connectivity SoC with enhanced co-existence performance in 65nm CMOS

2012 IEEE International Solid-State Circuits Conference, 2012

In recent years, the increasing popularity of mobile devices, such as smart-phones and tablets, i... more In recent years, the increasing popularity of mobile devices, such as smart-phones and tablets, is driving the demand for integrating multiple radios on a single SoC to reduce cost, form factor and external BOM [1]. These devices require ubiquitous wireless connectivity, which means concurrent operation with different radios. While concurrent operation of multiple radios brings excellent user experiences, there exist

Research paper thumbnail of Improved output beam quality using a hyperbolically flared semiconductor laser amplifier

Optoelectronic Materials and Devices, 1998

ABSTRACT

Research paper thumbnail of A 0.27mm2 13.5dBm 2.4GHz all-digital polar transmitter using 34%-efficiency Class-D DPA in 40nm CMOS

2013 IEEE International Solid-State Circuits Conference Digest of Technical Papers, 2013

ABSTRACT An all-digital polar transmit (TX) architecture exhibits advantages of low cost, low pow... more ABSTRACT An all-digital polar transmit (TX) architecture exhibits advantages of low cost, low power, as well as reconfigurability with full usage of digital computational power. The design challenge is the need for continuous innovation to further enhance power efficiency and minimize silicon area while achieving the best-in-class RF performance. The design must also meet the increasing demand of concurrent operation for multi-radio SoC integration. The presented Bluetooth TX demonstrates advancements in this direction with over 30% power and 66% area reduction.

Research paper thumbnail of A SiGe BiCMOS 16-element phased-array transmitter for 60GHz communications

2010 IEEE International Solid-State Circuits Conference - (ISSCC), 2010

Page 1. 218 • 2010 IEEE International Solid-State Circuits Conference ISSCC 2010 / SESSION 11 / R... more Page 1. 218 • 2010 IEEE International Solid-State Circuits Conference ISSCC 2010 / SESSION 11 / RADAR, mm-WAVE, & LOW-POWER TRANSCEIVERS / 11.3 11.3 A SiGe BiCMOS 16-Element Phased-Array Transmitter for 60GHz Communications ...

Research paper thumbnail of A World-Band Triple-Mode 802.11a/b/g SOC in 130-nm CMOS

IEEE Journal of Solid-State Circuits, 2009

Abstract A fully integrated system-on-a-chip (SOC) in 130-nm CMOS technology compliant with world... more Abstract A fully integrated system-on-a-chip (SOC) in 130-nm CMOS technology compliant with world-band 802.11 a/b/g is presented. This SOC integrates all blocks including 2.4-GHz/5-GHz RF tranceiver, baseband physical layer (PHY), and the medium access ...

Research paper thumbnail of A Fully-Integrated 16-Element Phased-Array Receiver in SiGe BiCMOS for 60-GHz Communications

IEEE Journal of Solid-State Circuits, 2011

A fully-integrated 16-element 60-GHz phased-array receiver is implemented in IBM 0.12-m SiGe BiCM... more A fully-integrated 16-element 60-GHz phased-array receiver is implemented in IBM 0.12-m SiGe BiCMOS technology. The receiver employs RF-path phase-shifting and is designed for multi-Gb/s non-line of sight links in the 60-GHz ISM band (IEEE 802.15.3c and 802.11ad). Each RF front-end includes variable-gain LNAs and phase shifters with each front-end capable of 360 variable phase shift (11.25 phase resolution) from 57 GHz to 66 GHz with coarse/fine gain steps. A detailed analysis of the noise trade-offs in the receiver array design is presented to motivate architectural choices. The hybrid active and passive signal-combining network in the receiver uses a differential cross-coupled Gysel power combiner that reduces combiner loss and area. Each array front-end has 6.8-dB noise figure (at 22 C) and the array has 10 dB to 58 dB programmable gain from single-input to output. Sixteen 60-GHz aperture-coupled patch-antennas and the RX IC are packaged together in multi-layer organic and LTCC packages. The packaged RX IC is capable of operating in all four IEEE 802.15.3c channels (58.32 to 64.8 GHz). Beam-forming and beam-steering measurements show good performance with 50-ns beam switching time. 5.3-Gb/s OFDM 16-QAM and 4.5 Gb/s SC 16-QAM links are demonstrated using the packaged RX ICs. Both line-of-sight links (7.8 m spacing) and non-line-of-sight links using reflections (9 m total path length) have been demonstrated with better than 18 dB EVM. The 16-element receiver consumes 1.8 W and occupies 37.7 mm of die area.

Research paper thumbnail of Carrier diffusion effect in tapered semiconductor-laser amplifier

IEEE Journal of Quantum Electronics, 1998

This paper proposes a theoretical model to study the beam amplification and the influence of the ... more This paper proposes a theoretical model to study the beam amplification and the influence of the lateral drift and diffusion on the tapered semiconductor-laser amplifier in great detail. The overall effect of the lateral drift and diffusion could be represented by an effective diffusion coefficient. The analysis, which treats the effective diffusion coefficient as a controllable parameter, shows that both the beam quality and optoelectrical property can be improved using a large effective diffusion coefficient. The analysis also indicates that the effective diffusion in the separate-confinement heterostructure layer could affect the beam quality in the quantum-well amplifiers. In addition, the thermal effect on the device performance is studied and its influence is found to be extremely significant for the high-diffusion cases

Research paper thumbnail of Output Beam Quality Improvement using a Narrow Input for Tapered Semiconductor Laser amplifiers

Conference on Lasers and Electro-Optics-Europe

Coherent high-power semiconductor lasers are important for many applications due to their compact... more Coherent high-power semiconductor lasers are important for many applications due to their compactness, low-cost, and possible integration with other photonic devices. Several types of semiconductor laser amplifiers have been proposed to increase the output power. Among them, the tapered semiconductor laser amplifier has demonstrated the highest output power and still has a good beam quality [1]. However, filamentation is still formed when the device is operated at a much higher power level. In the tapered amplifier, the linearly tailored gain region serves as the spherical expansion of the wave front. The expansion is not ideal because it does not start from a point source, which unfortunately does not practically exist. We propose that the input aperture with its size close to the wavelength could work like a point source and so significantly improves the output beam quality.

Research paper thumbnail of Opportunity and Challenge of Chiplet-Based HPC and AIoT

2021 International Symposium on VLSI Design, Automation and Test (VLSI-DAT), 2021

High-performance computing and AI tremendously drive technology innovations on architecture, algo... more High-performance computing and AI tremendously drive technology innovations on architecture, algorithm, memory, and semiconductor design, and continuously impact many fields from computation-intensive applications such as advanced driver-assistance system (ADAS) to highly-heterogeneous integrated, while performance-sensitive systems like 5G mobile and AIoT. Chiplet concept is considered a promising approach to alleviate the pressure on performance, power, cost, yield, and time to market raising with the increasing complexity of the fore-mentioned technologies. In this paper, we like to discuss the challenges and opportunities to satisfy these demands in conjunction with chiplet techniques.

Research paper thumbnail of Large Signal HBT Model and Integrated Circuit Design Using 300-Ghz Indium Phosphide HBT Technology

103 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005.This work describes a mode... more 103 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005.This work describes a modeling approach including the nonlinear effects in the base-collector region covering current blocking, velocity modulation and self-heating. Model is verified in terms of single devices and integrated circuits. Good fitting to the measured DC and high-frequency data from single HBTs is achieved. In terms of circuit verification, high-gain and wideband variable gain amplifier (VGA) is developed using a negative-RE approach. This circuit shows a single-ended S21 of 18 dB and a 3-dB bandwidth of 50 GHz, producing a gain-bandwidth product of 397 GHz which is over two times of the value measured from the VGA designed by conventional method in the same process. Linearity is measured, and the model developed in this work shows the best prediction, which indicates that the nonlinear mechanisms inherent in InP/InGaAs DHBTs cannot be neglected. More design examples are provided with technology considerations, giving a complete discussion of designing very high-frequency circuits.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Research paper thumbnail of Improved output beam quality using new-type flared semiconductor laser amplifiers

Technical Digest. Summaries of Papers Presented at the Conference on Lasers and Electro-Optics. Conference Edition. 1998 Technical Digest Series, Vol.6 (IEEE Cat. No.98CH36178), 1998

Time (ns) CTuM4 Fig. 3. A fragment of the pulse of p-Ge laser with a silicon spacer in the cavity... more Time (ns) CTuM4 Fig. 3. A fragment of the pulse of p-Ge laser with a silicon spacer in the cavity. B = 0.44 T, E = 0.57 kV/cm.

Research paper thumbnail of mm-Wave power-combining architectures

RF and mm-Wave Power Generation in Silicon, 2016

Abstract In this chapter, transformer-based hybrid power-combining in millimeter-wave power ampli... more Abstract In this chapter, transformer-based hybrid power-combining in millimeter-wave power amplifier design will be introduced. The discussion starts with conventional power combiners, the limitation of transformer-based voltage combining, and leads to the hybrid combining concepts covering serial-to-parallel and parallel-to-serial architecture.

Research paper thumbnail of Over 500 GHz InP heterojunction bipolar transistors

16th IPRM. 2004 International Conference on Indium Phosphide and Related Materials, 2004.

Page 1. 2004 International Conference on Indium Phoshide and Related Materials Conference Proceed... more Page 1. 2004 International Conference on Indium Phoshide and Related Materials Conference Proceedings 16th IPRM 3 I, May - 4, June 2004 Kagoshima, Japan 9:oo - 9:30 FA1 -1 Over 500 GHz InP Heterojunction Bipolar Transistors Milton Feng, Walid Hafez, Jie-Wei Lai ...

Research paper thumbnail of A silicon-based, all-passive, 60 GHz, 4-element, phased-array beamformer featuring a differential, reflection-type phase shifter

2010 IEEE International Symposium on Phased Array Systems and Technology, 2010

This paper presents an all-passive, 4-element, phased-array beamformer based on a differential, r... more This paper presents an all-passive, 4-element, phased-array beamformer based on a differential, reflectiontype phase shifter (RTPS) operating in the 60GHz band. The RTPS consists of a differential, vertically-coupled, coupledline hybrid and variable, parallel-LC, resonant, reflective loads, both of which enable low-loss millimeter-wave operation. The design considerations for a silicon-based implementation of all the beamformer elements are discussed in detail. In particular, the influence of the different RTPS components on its insertion loss is analyzed. The beamformer IC and a breakout of the RTPS are implemented using CMOS-only features of IBM's 8HP 0.13µm SiGe BiCMOS process, and employ areas of 2.1mm 2 and 0.33mm 2 , respectively, without probe pads. Differential s-parameter measurements at 60GHz show a phase-shift range greater than 150 o , insertion losses of 4-6.2dB in the RTPS and 14-16dB in the beamformer, and an isolation better than 35dB between adjacent beamformer channels. Measurements across temperature and process variations are also presented.

Research paper thumbnail of InP/InGaAs DHBT Large Signal Model for Nonlinearity Harmonic Predictions in ICs

In this work an improved large-signal transistor model is developed especially for InP DHBTs base... more In this work an improved large-signal transistor model is developed especially for InP DHBTs based on Agilent ADS SDD model platform. This model includes the nonlinear effects of current blocking and velocity modulation. The model is verified on Vitesse VIP2 300GHz InP/InGaAs DHBTs and the simulation results of different models are compared with measured results. In addition to the validation

Research paper thumbnail of Analysis of Beam Amplification in Hyperbolically Flared Semiconductor Laser Amplifiers

Proceedings of European Meeting on Lasers and Electro-Optics CLEOE-96, 1996

Research paper thumbnail of Self-aligned InP DHBTs for 150GHz digital and mixed signal circuits

International Conference on Indium Phosphide and Related Materials, 2005.

A production oriented manufacturing process for Indium Phosphide double-heterojunction bipolar tr... more A production oriented manufacturing process for Indium Phosphide double-heterojunction bipolar transistor (DHBT) devices that enables 150 GHz digital and mixed signal circuits is presented. These transistors have cut-off frequency (f) and maximum oscillation frequency (fmax) both over 300 GHz and open-base breakdown voltage (BVceo) over 4 V. Common Mode Logic (CML) ring oscillators have exhibited 1.95 ps gate delay and

Research paper thumbnail of Submicron scaling InP/InGaAs single heterojunction bipolar transistor technology with f/sub T/ > 400 GHz for >100 GHz applications

25th Annual Technical Digest 2003. IEEE Gallium Arsenide Integrated Circuit (GaAs IC) Symposium, 2003., 2003

ABSTRACT

Research paper thumbnail of 300 GHz InP DHBT large signal model including current blocking effect and validated by Gilbert multiplier circuits

IEEE Compound Semiconductor Integrated Circuit Symposium, 2005. CSIC '05., 2005

ABSTRACT

Research paper thumbnail of A 1V 17.9dBm 60GHz power amplifier in standard 65nm CMOS

2010 IEEE International Solid-State Circuits Conference - (ISSCC), 2010

... 23.6 A 1V 17.9dBm 60GHz Power Amplifier in Standard 65nm CMOS Jie-Wei Lai1, AlbertoValdes-Gar... more ... 23.6 A 1V 17.9dBm 60GHz Power Amplifier in Standard 65nm CMOS Jie-Wei Lai1, AlbertoValdes-Garcia2 ... Figure 23.6.7 summarizes the state-of-the-art 60GHz silicon PAs. The proposed 1V VDD CMOS PA compares favorably to the recent results in CMOS [1-4] and SiGe [5]. ...

Research paper thumbnail of A 4-in-1 (WiFi/BT/FM/GPS) connectivity SoC with enhanced co-existence performance in 65nm CMOS

2012 IEEE International Solid-State Circuits Conference, 2012

In recent years, the increasing popularity of mobile devices, such as smart-phones and tablets, i... more In recent years, the increasing popularity of mobile devices, such as smart-phones and tablets, is driving the demand for integrating multiple radios on a single SoC to reduce cost, form factor and external BOM [1]. These devices require ubiquitous wireless connectivity, which means concurrent operation with different radios. While concurrent operation of multiple radios brings excellent user experiences, there exist

Research paper thumbnail of Improved output beam quality using a hyperbolically flared semiconductor laser amplifier

Optoelectronic Materials and Devices, 1998

ABSTRACT

Research paper thumbnail of A 0.27mm2 13.5dBm 2.4GHz all-digital polar transmitter using 34%-efficiency Class-D DPA in 40nm CMOS

2013 IEEE International Solid-State Circuits Conference Digest of Technical Papers, 2013

ABSTRACT An all-digital polar transmit (TX) architecture exhibits advantages of low cost, low pow... more ABSTRACT An all-digital polar transmit (TX) architecture exhibits advantages of low cost, low power, as well as reconfigurability with full usage of digital computational power. The design challenge is the need for continuous innovation to further enhance power efficiency and minimize silicon area while achieving the best-in-class RF performance. The design must also meet the increasing demand of concurrent operation for multi-radio SoC integration. The presented Bluetooth TX demonstrates advancements in this direction with over 30% power and 66% area reduction.

Research paper thumbnail of A SiGe BiCMOS 16-element phased-array transmitter for 60GHz communications

2010 IEEE International Solid-State Circuits Conference - (ISSCC), 2010

Page 1. 218 • 2010 IEEE International Solid-State Circuits Conference ISSCC 2010 / SESSION 11 / R... more Page 1. 218 • 2010 IEEE International Solid-State Circuits Conference ISSCC 2010 / SESSION 11 / RADAR, mm-WAVE, & LOW-POWER TRANSCEIVERS / 11.3 11.3 A SiGe BiCMOS 16-Element Phased-Array Transmitter for 60GHz Communications ...

Research paper thumbnail of A World-Band Triple-Mode 802.11a/b/g SOC in 130-nm CMOS

IEEE Journal of Solid-State Circuits, 2009

Abstract A fully integrated system-on-a-chip (SOC) in 130-nm CMOS technology compliant with world... more Abstract A fully integrated system-on-a-chip (SOC) in 130-nm CMOS technology compliant with world-band 802.11 a/b/g is presented. This SOC integrates all blocks including 2.4-GHz/5-GHz RF tranceiver, baseband physical layer (PHY), and the medium access ...

Research paper thumbnail of A Fully-Integrated 16-Element Phased-Array Receiver in SiGe BiCMOS for 60-GHz Communications

IEEE Journal of Solid-State Circuits, 2011

A fully-integrated 16-element 60-GHz phased-array receiver is implemented in IBM 0.12-m SiGe BiCM... more A fully-integrated 16-element 60-GHz phased-array receiver is implemented in IBM 0.12-m SiGe BiCMOS technology. The receiver employs RF-path phase-shifting and is designed for multi-Gb/s non-line of sight links in the 60-GHz ISM band (IEEE 802.15.3c and 802.11ad). Each RF front-end includes variable-gain LNAs and phase shifters with each front-end capable of 360 variable phase shift (11.25 phase resolution) from 57 GHz to 66 GHz with coarse/fine gain steps. A detailed analysis of the noise trade-offs in the receiver array design is presented to motivate architectural choices. The hybrid active and passive signal-combining network in the receiver uses a differential cross-coupled Gysel power combiner that reduces combiner loss and area. Each array front-end has 6.8-dB noise figure (at 22 C) and the array has 10 dB to 58 dB programmable gain from single-input to output. Sixteen 60-GHz aperture-coupled patch-antennas and the RX IC are packaged together in multi-layer organic and LTCC packages. The packaged RX IC is capable of operating in all four IEEE 802.15.3c channels (58.32 to 64.8 GHz). Beam-forming and beam-steering measurements show good performance with 50-ns beam switching time. 5.3-Gb/s OFDM 16-QAM and 4.5 Gb/s SC 16-QAM links are demonstrated using the packaged RX ICs. Both line-of-sight links (7.8 m spacing) and non-line-of-sight links using reflections (9 m total path length) have been demonstrated with better than 18 dB EVM. The 16-element receiver consumes 1.8 W and occupies 37.7 mm of die area.

Research paper thumbnail of Carrier diffusion effect in tapered semiconductor-laser amplifier

IEEE Journal of Quantum Electronics, 1998

This paper proposes a theoretical model to study the beam amplification and the influence of the ... more This paper proposes a theoretical model to study the beam amplification and the influence of the lateral drift and diffusion on the tapered semiconductor-laser amplifier in great detail. The overall effect of the lateral drift and diffusion could be represented by an effective diffusion coefficient. The analysis, which treats the effective diffusion coefficient as a controllable parameter, shows that both the beam quality and optoelectrical property can be improved using a large effective diffusion coefficient. The analysis also indicates that the effective diffusion in the separate-confinement heterostructure layer could affect the beam quality in the quantum-well amplifiers. In addition, the thermal effect on the device performance is studied and its influence is found to be extremely significant for the high-diffusion cases