A 24–30 GHz GaN-on-SiC T/R Front-End Module with 37.1-dBm Output Power and 34.4% PAE

This paper presents a $\mathbf{2 4 - 3 0 ~ G H z}$ transmit–receive (T/R) front-end module (FEM) on a $150-\mathrm{nm}$ GaN-on-SiC HEMT process. The transmitting chain is constructed by two fully symmetrical push-pull power amplifier (PA) with a balun as the power distributing network. The waveform engineering technique is used in the impedance matching for high efficiency. The second harmonic is controlled by exploiting the inherent isolation of the balun’s center-tap point which helps to optimize the second harmonic impedance without affecting the fundamental response. The receiving chain consists of a three-stage low-noise amplifier (LNA) with a gain of over 20 dB and wideband noise matching across the operation bandwidth. A high-order stacked-transistor single-pole double-throw (SPDT) switch is designed with a low insertion loss of 0.75 dB and an IP ${ }_{1 \mathrm{~dB}}$ of 44 dBm, ensuring no gain compression in transmitting mode. In measurement, the proposed FEM operating across $\mathbf{2 4 - 3 0 ~ G H z}$ demonstrates a peak $\boldsymbol{P}_{\text {sat }}$ of $\mathbf{3 7. 1}$ dBm and peak power added efficiency (PAE) of $34.4 \%$ in the Tx mode. An EVM of $5.54 \%$ and an average output power of 30.1 dBm with a 64-QAM modulated input signal of 100 MHz bandwidth at 26 GHz are realized. In the Rx mode, the front-end demonstrates an NF of less than 3.1 dB with a gain of $20-21.3 \mathrm{~dB}$. The FEM chip area is $3.6 \times 2.7 \mathrm{~mm}^{2}$.