Broadband Millimeter-Wave 5G Power Amplifiers in FD-SOI CMOS vs. GaN HEMTs for RF Front-End Module Design

This paper presents circuit design with measured data on two broadband millimeter-wave (mm-Wave) power amplifiers (PAs): one designed in a 22nm fully depleted silicon on insulator (FD-SOI) CMOS process, and that the other in a 40nm Gallium Nitride (GaN) high-electron-mobility transistor (HEMT) process. These mm-Wave PAs are designed to cover key portions of the fifth-generation (5G) FR2-band (i.e., 24.25 - 52.6 GHz). The FD-SOI P A achieves saturated output power ($P_{OUT, sat}$) of ~ 14 dBm and peak power-added-efficiency (P AE) of ~ 20% with ~ 14 dB of gain and 3-dB bandwidth (BW) from~ 19.1 - 46.5 GHz in measurement, and the GaN P A achieves measured $P_{OUT, sat}$ of ~24 dBm and peak P AE of ~ 20% with~ 20 dB of gain and 3-dB BW from ~ 19.9 - 35.2 GHz. Both PAs' measured data is in good agreement with the post-layout parasitics extracted (PEX) electromagnetic (EM) simulated data. The EM PEX design simulations of a 3^rd Watt-level GaN PA is also presented. Data from these PAs are used to estimate how many front-end modules (FEMs) would be necessary for a transmitter (Tx) array targeting a fixed level of equivalent isotropic radiated power (EIRP). The resulting half power beam width (HPBW) of its antenna array is calculated, with the smaller arrays using GaN FEMs showing considerably wider HPBW than the all-Si arrays, alleviating the thorny mm- Wave line-of-sight (LOS) blocking effects significantly.