A 12.2--19.1 GHz High-Selectivity CMOS Power Amplifier Chip With Two-Stage Transformer-Based Filtering Matching Network

This letter presents a novel integrated broadband filtering power amplifier (FPA) with a two-stage transformer-based bandpass matching network. The proposed filtering input matching network (FIMN) is composed of a magnetically and capacitively coupled resonator (MCCR) and a cascaded matching balun. The MCCR is realized by incorporating capacitors within the transformer structure, introducing two transmission zeros(TZs) with a highly compact layout. The matching balun further enhances out-of-band rejection and eases impedance matching, achieving broadband performance. For verification, a two-stage Ku-band cascode FPA was designed and fabricated with a core area of 0.59 mm2in a 180-nm CMOS process. Measured results demonstrate a peak gain of 23.8 dB with a 3-dB bandwidth of 12.2–19.1 GHz and 75.8-/62.9-dBc stopband rejection. At 15 GHz, the FPA delivers a$P_{\mathrm {sat}}$of 19.2 dBm and a power-added efficiency (PAE) of 26.0%. The measured$P_{\mathrm {avg}}$of 13.4 dBm is achieved with −25.0-dB EVMrmsand −30.2-dBc adjacent channel leakage ratio (ACLR) under 100-MHz single-carrier 64-QAM signals.