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Frank Zhang

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Last update: 18 May 2008

I was a student in the Department of Electrical Engineering, Columbia University, New York, NY. My Ph.D dissertation is titled "Ultra-wideband Pulse Radio Receiver in Digital CMOS", my research was completed under the guidance of Prof. Peter Kinget. I graduated in May 2008 and am currently a CMOS RFIC engineer with Texas Instruments' Wireless Organization in Dallas, TX. I received my BE and MS degrees in electrical engineering from The Cooper Union for the Advancement of Science and Art, New York, NY.

Ph.D Research

Ultra-wideband Pulse Radio Receiver

UWB Pulse Radio Receiver An 8-channel 3.1-9.5 GHz UWB pulse radio receiver is realized using a double-conversion architecture with discrete-time wideband IF correlation. The pulse templates for correlation are pre-stored in memories which allows fast band switching and agile interferer avoidance since no PLL resettling is required. This high data-rate receiver covers both the lower and higher bands of the UWB spectrum and avoids the use of tunable bandpass filters that require manual adjustments for each channel and occupy a large area. The area of our receiver is small thanks to the extensive use of high-speed digital circuitry and memories that will scale in size and performance as technology improves.
  • F. Zhang, R. Gharpurey and P. Kinget, "A 3.1-9.5 GHz Agile UWB Pulse Radio Receiver with Discrete-Time Wideband-IF Correlation in 90nm CMOS," IEEE Radio Frequency Integrated Circuits Symposium (RFIC), June 2008.

Components and Circuits Underneath Integrated Inductors

Metal Fills under an Inductor The idea of utilizing the area under an inductor sprout from the practical consideration of metal density requirement. On-chip inductors are large, but they are often made of only two metal layers. Placing metal fills inside or near the inductor increases the metal density count but has the possible drawback of decreasing the Q of the inductor through eddy current loss. We established a relationship between fill cell size and inductor Q through extensive EM simulations and measurements on test structures.
VCO in a Coil We used layout techniques to minimize eddy current loss and magnetic coupling between the devices and the inductor, and constructed a complete voltage-controlled oscillator (VCO) inside an inductor. Measurement results show that this compact VCO has an equal performance in phase noise and output power as compared to a traditional VCO while reducing the area by about 50%. The techniques presented in this paper are general and can be implemented in most layouts without extra post-processing steps.
  • F. Zhang, C.-F. Chu and P. Kinget, "Voltage-controlled oscillator in the coil," IEEE Custom Integrated Circuits Conference (CICC), October 2005, pp. 587-590. PDF
  • F. Zhang and P. Kinget, "Design of Components and Circuits Underneath Integrated Inductors" IEEE Journal of Solid-State Circuits, pp. 2265-2271, Oct. 2006. PDF

Low Power Distributed Low Noise Amplifier

Distributed Amplifier Chip Photo We introduced a design methodology for low power MOS distributed amplifiers (DAs). The bias point of the MOS devices is optimized so that the DA can be used as a low-noise amplifier (LNA) in broadband applications. A prototype 9-mW LNA with programmable gain was implemented in a 0.18um CMOS process. The LNA provides a flat gain, S21, of 8 +/- 0.6 dB from DC to 6.2 GHz, with an input impedance match, S11, of 16 dB and an output impedance match, S22, of 10 dB over the entire band. The 3-dB bandwidth of the distributed amplifier is 7 GHz, the IIP3 is +3 dBm, and the noise figure ranges from 4.2 to 6.2 dB. The gain is programmable from 10 dB to +8 dB while gain flatness and matching are maintained.
  • F. Zhang and P. Kinget, "Low Power Programmable-Gain CMOS Distributed LNA for Ultra-Wideband Applications," in Digest of Technical Papers IEEE Symposium on VLSI circuits, June 2005, pp. 78-81. PDF
  • F. Zhang and P. Kinget, "Low Power Programmable Gain CMOS Distributed LNA," IEEE Journal of Solid-State Circuits, vol. 41, no 6, June 2006, pp. 1333-1343. PDF