A 28-GHz highly efficient Class-J SiGe power amplifier with pi-type load network

This paper presents a 28-GHz, single-stage, Class-J Power Amplifier for potential use in mm-Wave 5G MIMO applications. A pi-type load network is proposed to provide the required fundamental and second harmonic impedance terminations for a Class-J operation mode. The PA is implemented in Infineon's 130 nm SiGe BiCMOS process achieving a saturation output power P s a t = 16.7 d B m and a remarkably high power-added efficiency P A E = 42.8 % at 28 GHz. Moreover, the proposed PA exhibits an impressive average PAE of 17.2 % and 14.7 % respectively, while enabling 3 and 6 Gbps 64-QAM operation at an average output power of 8.09 and 7.15 dBm respectively. The in-band and out-of-band linearities, are < -26 dB and <-26.5 dBc respectively in the absence of any digital pre-distortion. • The PA achieves one of the highest reported power-added efficiency P A E = 42.8 % at 28 GHz. • The proposed output matching network distinguishes itself from the simplest of class-J/AB/B output matching networks because of the shunt capacitor C P 1 which operates in parallel with transistor's output capacitance. The inclusion of C P 1 in the OMN becomes imperative to harness the additional efficiency enhancements brought about by the class-J mode. • This paper includes an analytical approach for designing this operational mode, complete with comprehensive mathematical expressions for implementing the proposed output matching network. • A variety of performed measurements are presented verifying the analytical designing approach.