A V-Band Four-Channel Phased Array Transmitter Front-End with 0.7° Phase Step and 20 dB Gain Dynamic Range

This article reports a V -band phased array transmitter front-end module, in which a four-channel RF beamforming IC is included with power amplifiers (PAs), active phase shifters, and power dividers. The PA is linearized by a cold-FET-controlled coupled inductor, improving AM to AM and AM to PM properties. The vector sum of I and Q signals from an active I/Q generator determines the amplitude and phase of a synthesized signal. The non-ideal effects of the vector summing circuit are overcome by introducing a 45° phase shifter implemented with a C-L-C network. It shows 0.1 dB rms gain and 2° rms phase errors at 60 GHz, with 3-bit gain and 9-bit phase controls in the 20 dB dynamic range. It achieves an OP1dB of 10.8 dBm and a peak gain of 14.3 dB in the 3-dB frequency bandwidth of 57-63.3 GHz. A 10 mil thick antenna substrate is used to implement four-channel series-fed patch antennas. The four-channel chip is connected to the antenna module by wire bonding, of which effects are compensated by impedance matching networks on the substrate. The entire antenna feeding network shows less than 2 dB insertion loss, which shows loss and phase variations of 0.3 dB and 3.5° at 60 GHz, respectively. The far-field beam pattern of the four-channel transmitter module is also measured.