Single and Four-Element $Ka$ -Band Transmit/Receive Phased-Array Silicon RFICs With 5-bit Amplitude and Phase Control

Ka-band SiGe BiCMOS single- and four-element phased arrays capable of both transmit and receive operation with 5-bit phase and amplitude control are presented. The design is based on the All-RF architecture with RF phase shifters and attenuators, and a 4:1 passive power combining/dividing network. The four-element array results in an average gain of ~ 0 dB per channel and a noise figure of 9.0 dB, and is designed to be placed behind III-V T/R modules. The rms phase error is 5.6?? (5-bit operation) and < 12.5?? (4-bit operation) over a 2 or 5 GHz instantaneous bandwidth, respectively, centered at around 36.5 GHz. In the receive mode, the input P1dB is -16 dBm per channel (IIP3 of - 5.9 dBm), and in the transmit mode, the output P1dB is +4-5 dBm, all at 35-36 GHz. The measured isolation between the channels is better than 30 dB. The array maintained excellent phase characteristics up to 100??C with no change in the rms phase error. Also, ten different four-element phased arrays were tested (40 channels) and result in an rms gain variation of 0.5 dB at 34-39 GHz. The four-element array consumes 171 and 142 mW in the Tx and Rx modes from 1.8 V, and occupies an area of 2.0 ?? 2.02 mm². To our knowledge, this is the smallest and lowest power consumption on-chip K ??-band phased-array to-date.