Amplifiers are indispensable for systems and impose significant challenges for on-chip mm-Wave/THz systems, including power amplifiers in the transmitter and low noise amplifiers in the receiver. High amplifier performances are hard to achieve due to the large losses of inter-stage matching network. The performance degradation are induced by different factors, such as circuit biasing networks, simulation inaccuracy introduced non-optimal design, on-chip crosstalk. We have invented the transformer based inter-stage matching scheme to effectively address all the critical issues for on-chip mm-Wave/THz amplifiers with several prominent advantages. First, it provides inherent DC blocking between stages to allow individual optimum biasing for each stage. Second, it supports flexible voltage/current gain performance by adjusting the winding turns ratio to enable active/passive co-optimization. Third, the natural inter-stage T matching network accomplishes impedance matching with symmetrical configurations and immunity to on-chip coupling noises with fully differential configuration. Fourth, physically spanned input and output signals benefits good isolation and compact physical design minimizes losses; Fifth, differential structure facilitates accurate performance estimation through EM simulations and design optimization. This method has been widely used by many other groups.
With the invented transformer based inter-stage matching, we have demonstrated a series of high performance mm-wave CMOS amplifiers, starting from a 60 GHz power amplifier (PA) with the gain > 30 dB, a 100 GHz PA with the highest saturated output power Psat about 15 dBm in CMOS and a 100 GHz Low Noise Amplifier (LNA) with the best noise figure (NF) of < 8 dB in 2012, then a wideband 128-157 GHz amplifier with the power gain higher than 10 dB, to the fastest amplifier at 200 GHz with the maximum gain about 8 dB in 2012, all in CMOS technologies. We have published 17 papers and filed 1 patent disclosure in this domain.
- Y. Ye, B. Yu, X. Ding, X. Liu, and Q. J. Gu, “High Energy-Efficiency High Bandwidth-Density Sub-THz Interconnect for the Last-Centimeter Chip-to-Chip Communications,” IEEE International Microwave Symposium IMS2017
- Y. Ye, B. Yu, and Q. J. Gu, “A 165GHz OOK Transmitter with 10.6% Peak DC-to-RF Efficiency in 65nm Bulk CMOS,” IEEE International Microwave Symposium 2016
- Y.-T. Chang, Y. Ye, C. Domier, and Q. J. Gu, “A Ultra-Wideband CMOS PA with Dummy Filling for Reliability,” 2015 IEEE International Wireless Symposium
- D. Huang, R. Wong, Q. Gu, N. Wang, T. Ku, C. Chien, and M.F. Chang, “A 60GHz CMOS Differential Receiver Front-End Using On-Chip Transformer for 1.2 Volt Operation with Enhanced Gain and Linearity,” IEEE Symposium on VLSI Circuits, pp. 144-145, June 2006.
- Y.-C. Liu, Q. J. Gu, T. LaRocca, N.-Y. Wang, Y.-C. Wu, and M.-C. F. Chang, “A 60 GHz High Gain Transformer-Coupled Differential Amplifier in CMOS,” Asia-Pacific Microwave Conference (APMC), pp. 932-935, November 2010, Best Student Paper Award
- Y-C. Liu, A. Tang, N.-Y. Wang, Q. J. Gu, R. Berenguer, H.-H. Hsieh, P.-Y. Wu, C. Jou, and M.-C. F. Chang, “A V-band Self-Healing Power Amplifier with Adaptive Feedback Bias Control in 65 nm CMOS,” IEEE Radio Frequency Integrated Circuits Symposium (RFIC) 2011
- Z. Xu, Q. J. Gu, and M.-C. F. Chang, “A 100-117GHz W-band CMOS Power Amplifier with On-Chip Adaptive Biasing,” IEEE Microwave and Wireless Components Letters, vol. 21, no. 10, pp 547-549, Oct. 2011
- Z. Xu, Q. J. Gu, and M.-C. F. Chang, “A Three Stage, Fully Differential 128 – 157 GHz CMOS Amplifier with Wide Band Matching,” IEEE Microwave and Wireless Components Letters, vol. 21, no. 10, pp 550-552, Oct. 2011
- J. Gu, Z. Xu, and M.-C. F. Chang, “Two-Way Current Combining W-Band Power Amplifier in 65 nm CMOS,” IEEE Transactions on Microwave Theory and Techniques, vol. 60, no. 5, pp. 1365-1374, May 2012
- Tang, D. Murphy, F. Hsiao, Q. J. Gu, Z. Xu, G. Virbila, Y.-H. Wang, H. Wu, L. Nan, Y.-C. Wu, and M.-C. F. Chang, “A CMOS 135-150 GHz 0.4 dBm EIRP Transmitter with 5.1dB P1dB Extension Using IF Envelope Feed-Forward Gain Compensation,” 2012 IEEE MTT-S International Microwave Symposium, June 2012, Honorable Mention Student Paper Award