A Ku-Band Self-Biased Bidirectional Amplifier in $0.25\ \mu\mathrm{m}$ PHEMT Technology

A fully integrated Ku-band (14∼18GHz) self-biased bidirectional amplifier (BDA) is demonstrated in a $0.25\mu\mathrm{m}$ GaAs pHEMT technology. The proposed bidirectional amplifier comprises a power amplifier (PA) and a low noise amplifier (LNA) for T/R modules of phased array with in/output switches. In transmitting mode, the BDA achieves a flat small signal gain of $24.2\pm 0.8\ \text{dB}$, the measured saturated output power is 23.6 dBm with 28.3% peak power added efficiency (PAE) at 16 GHz. In receiving mode, the BDA achieves a flat gain of $13.1\pm 0.7\ \text{dB}$. The measured minimum noise figure is 4.2 dB at 16 GHz and below 4.7 dB over the band. And its in/output P1 dB are 10.3 dBm and 22.8 dBm at 16 GHz, respectively. The size of the MMIC is $2.15\ \text{mm}\times 1.55\ \text{mm}$. To the authors' knowledge, this is the first demonstration of Ku-band self-biased BDA, and it attains state-of-the-art peak PAE in Tx mode, and in/output P1dB in Rx mode.