Title :
CMOS I/Q demodulator using a high-isolation and linear mixer for 2 GHz operation
Author_Institution :
Samsung Electron. Co. Ltd., Suwon, South Korea
Abstract :
An I/Q direct demodulator employing passive mixers and a phase shifter for 2 GHz operation is designed and implemented with 0.35 μm CMOS technology. CMOS switching elements are used to improve the linearity and isolation property of the mixer. A DC bias to the switching elements is devised to reduce LO power for the passive mixer. This bias effect on linearity and isolation is analyzed. A low-loss simple RC/CR pair with a feedback network is used to reduce the LO power and maintain I/Q channel balance instead of using a poly-phase network. Measurements showed 15 dBm IIP3 (third order input intercept point) for 4 dBm LO power, 62 dBc isolation, and 2.8° phase imbalance.
Keywords :
CMOS analogue integrated circuits; RC circuits; UHF integrated circuits; UHF mixers; UHF phase shifters; circuit feedback; demodulators; integrated circuit design; nonlinear network synthesis; passive networks; switching circuits; 0.35 micron; 2 GHz; CMOS I/Q demodulator; I/Q direct demodulator; channel balance; feedback network; high-isolation mixer; linear mixer; passive mixer design; phase imbalance; phase shifter; poly-phase network; switching elements; third order input intercept point; CMOS technology; Demodulation; Integrated circuit noise; Isolation technology; Linearity; Noise figure; Phase shifters; Power measurement; Radio frequency; Switches;
Conference_Titel :
Radio Frequency Integrated Circuits (RFIC) Symposium, 2004. Digest of Papers. 2004 IEEE
Print_ISBN :
0-7803-8333-8
DOI :
10.1109/RFIC.2004.1320526
