Linear CMOS power amplifier at Ka-band with ultra-wide video bandwidth

Abstract

A highly linear power amplifier (PA) with ultra-wide video bandwidth is designed at a Ka-band for 5G application. To get a high linearity with high efficiency, a deep class-AB topology with 2nd harmonic control circuits is employed, reducing the 3rd order nonlinearity. Further, an efficient low-drop out (LDO) regulator is proposed to suppress the memory effect generated by the envelope and fundamental nonlinear mixing. The PA, composed of 3 cascaded common-source (CS) stages, achieves peak PAE of 21.8% at output power of 14 dBm with 22 dB gain. The 3rd order inter-modulation distortion (IMD3) at an output power of 5 dBm is under −30 dBc for a video bandwidth of 1 GHz. The PA and LDO are fabricated in a 65 nm CMOS process and occupy 0.53 mm2.