A Ka-band T/R front-end for phased array radar

In this paper, a Ka-band transmitter/receiver (T/R) front-end for a phased-array radar is proposed. The transceiver includes a receiver channel and a transmitter channel. A function link shared with the receiver channel and the transmitter channel is comprised of a 5-bit phase shifter and a variable gain amplifying circuit including an attenuator and a low noise amplifier. Connection to either the final power amplifier on transmitter or the LNA on receiver is accomplished by using two single-pole double-throw switches (SPDTs). Experimental results of the front-end verify the validity of the design. A noise figure of 4.9 to 5.6 dB, a receiver gain of 24.4 to 29.4 dB and a output power from 0.74 W to 1 W are obtained within a frequency range from 34.5 GHz to 35.5 GHz. The digital phase shift provides 10.2° root-mean square(RMS) phase shift error at 35 GHz.