A High-Power Packaged Four-Element -Band Phased-Array Transmitter in CMOS for Radar and Communication Systems

This paper presents a four-element X-band phased-array transmitter in 0.13-μm CMOS. The design is based on the all-RF architecture and contains a 5-bit phase shifter (lowest bit is used as a trim bit), 4-bit gain control (to reduce the rms gain error), and power amplifiers capable of delivering a PSAT of 13.5 dBm per channel at 8.5-10.5 GHz. The chip can be used in the linear mode for communication systems and in the saturated mode for frequency-modulated continuous-wave radar systems, and therefore, extensive analysis is done on the phase shifter distortion versus input power. Spectral regrowth and error vector magnitude measurements indicate that the chip can support at least 20-MSym/s quadrature phase-shift keying and binary phase-shift keying modulation at an output power of +5 dBm per channel. Packaging techniques based on chip-on-board and quad flat no-lead (QFN) modules have been implemented with the four-channel chip, and both show a nearest neighbor coupling of -30 dB at 8-10 GHz, limited by bond-wire coupling. The chip dimensions are 2.9×3.0 mm2 and it consumes 870 mW from 2- and 3-V power supplies.