A 28/37-GHz Frequency-Reconfigurable Dual-Band 1-Channel Front-End IC for 5G Communication Radios

This article presents a 28/37-GHz frequency-reconfigurable dual-band beamforming 1-channel front-end integrated circuit (IC) for fifth-generation (5G) communication. The proposed IC integrates frequency-reconfigurable variable-gain phase shifters (VGPSs) in the transmitter (TX) and receiver (RX) paths. The VGPS enables gain and phase controls with a single block in the dual-frequency bands using an active vector modulator including the proposed frequency-reconfigurable I/Q generator. A frequency-reconfigurable power amplifier with optimal performance at dual bands that uses reconfigurable transformers at the output and interstage matching networks is introduced. A dual-band variable-gain low-noise amplifier (LNA) is also introduced, utilizing a combined structure of a high-k input transformer and a differential common-gate (CG) for simultaneous noise and input matching at the dual bands. The dual-band switches for the antenna and channel show high isolation and low-noise-figure (NF) degradation at dual bands. Thanks to the proposed frequency-reconfigurable VGPS, rms phase errors of 0.9 and 0.62 are achieved at 28 and 37 GHz, respectively, with 6-bit phase control resolution. The rms gain errors of 0.22 and 0.23 dB are achieved at 28 and 37 GHz, respectively, with 4-bit gain control resolution. The front-end IC achieves 13.5-and 13.5-dBm TX output 1-dB compression points and 15.5% and 14.1% TX efficiencies at 28 and 37 GHz, respectively. It also achieves 4.4-and 4.9-dB RX NFs at 28 and 37 GHz, respectively. The front-end IC is tested under 200-MHz 64-quadrature amplitude modulation (QAM) 5G new radio (NR) signals with a 7.62-dB peak-to-average power ratio. It delivers 9.3-and 8.6-dBm average output power at 28 and 37 GHz, respectively.