Millimeter-Wave Frequency Reconfigurable Dual-Band CMOS Power Amplifier for 5G Communication Radios

This article presents two millimeter-wave frequency reconfigurable dual-band CMOS power amplifiers (PAs) for fifth-generation (5G) communications comprising a single-stage dual-band PA and a two-stage dual-band PA for higher gain. The PAs cover multiple 5G communication bands, n257 (26.5-29.5 GHz) and n260 (37-40 GHz), which use reconfigurable transmission line transformers (TLTs) for output, input, and interstage matching networks. These matching networks allow the operating frequency bands to be changed, thereby achieving optimum performance. The integrated mode selection switches in the transformers reconfigure the inductances of the TLTs to cover two frequency bands, which allows the PAs to have small overall chip sizes. These are fabricated in a 28-nm bulk CMOS process. The single-stage dual-band PA achieves 20.2-/19.1-dBm saturated output power ( ${P}_{sat}$ ), 18.7-/18.6-dBm 1-dB compressed output power ( ${P}_{1 dB}$ ), and 33.6%/32% peak power-added efficiency (PAE) at 26.5 and 37 GHz, respectively, while occupying a chip area of 0.11 mm(2). The two-stage dual-band PA achieves 19.1-/19.5-dBm ${P}_{sat}$ , 17-/17.8-dBm ${P}_{1 dB}$ , and 31.3%/30.5% PAE at 26.5 and 37 GHz, respectively, while occupying a chip area of 0.165 mm(2). Both PAs are tested under 64-quadrature amplitude modulation signals with a 100-MHz channel bandwidth. The single-stage PA achieves 14.7- and 12.3-dBm average output powers ( ${P}_{avg}$ ) with -25.1- and -25-dB error vector magnitudes (EVMs) at 26.5 and 37 GHz, respectively. The two-stage PA achieves 12.3- and 11.6-dBm ${P}_{avg}$ 's with -25.3- and -25.1-dB EVMs at 26.5 and 37 GHz, respectively.