A K-/Ka-Band 21.4 dBm Power Amplifier with Four-Way Twisted Combiner in $0.13\ \mu\mathrm{m}$ SiGe BiCMOS

Toward high output power and wide bandwidth power amplifier (PA) design in $0.13\ \ \mu \mathrm{m}$ BiCMOS for 5G communication, this paper introduces a four-way transformer-based power combiner. Moreover, in order to reduce the energy leak of high power amplifier, both output power combiner and input splitter are adopted twisted eight-shaped transformer structure. Besides, compared to conventional eight-shaped transformer, this structure has better input impedance uniformity. The PA electromagnetic simulation results demonstrate 23 dB small-signal gain, 28.1% power added efficiency (PAE), 20.3 dBm 1-dB compression point output power (OP1dB), 21.4 dBm saturated output power (OPsat). This PA has 13 GHz 3-dB bandwidth (25 to 38 GHz) with a core area of 0.344 mm² ($0.4\ \text{mm} \times 0.86\ \text{mm}$).