A 27 dBm 5-18 GHz Multifunction Bidirectional amplifier using GaAs pHEMT process

Design and realization of a 27 dBm broadband multifunction bidirectional amplifier (BDA) using GaAs pHEMT process in the frequency range $\mathrm{5 - 1 8} \mathrm{~ G H z}$ is presented in this article. The proposed design consists of combination of feedback and stacked non-uniform distributed power amplifier(SNDPA) in the transmit mode(Tx), a receive protection limiter, a 4 stage low noise amplifier and a digitally controlled attenuator in the receive mode $(\mathrm{R x})$ integrated in a single chip. It also features an on-chip power detector to sense the functioning of the power amplifier (PA). The transmit and receive path is isolated by a high power handling switch at the output end. The resulting BDA gives a small signal gain of $30 \pm 1$ dB and delivers a saturated output power of $27 \mathrm{dBm}(0.5 \mathrm{~W})$ in the Transmit mode. In the Receive mode, a small signal gain of 30 dB with maximum noise figure of 6 dB is achieved over the entire bandwidth. On-chip TTL drivers are integrated to ease the control of attenuator bits and switch direction. The current consumption in the transmit and receive modes are 500 mA and 135 mA respectively. The size of core chip is around $5.3 \times 3.4$ $\mathrm{m m}^{2}$.