An X-Band Switchless Bidirectional GaN MMIC Amplifier for Phased Array Systems

An X-Band switchless bidirectional amplifier (BDA) in a 0.25 μm gallium-nitride (GaN) on SiC process is introduced. The proposed bidirectional amplifier comprises of a 1 W power amplifier (PA) and a low noise amplifier (LNA) for T/R modules of phased array systems without any aid of switches. In receive mode, the BDA has flat gain of 20.2±1 dB and shows wideband input matching at 8 to 12 GHz. The minimum noise figure is 4.3 dB at 10.4 GHz and below 5 dB across the X-Band. In transmit mode, the small signal gain of the PA is 27±3 dB, its P1 dB is about 27 dBm, and its saturated output power is over 30 dBm at 8 to 12 GHz. The PA consumes 220 mA of quiescent current with 20 V power supply. While one mode is working, the other mode transistors are off and their parasitic capacitance has been already considered in design stage to minimize performance degradation and leakage. The total chip size is 2.5 mm×1.87 mm including pads.