A 24–40-GHz Broadband Beamforming TRX Front-End IC With Unified Phase and Gain Control for Multiband Phased Array Systems

This article presents a 24–40-GHz broadband beamforming transmit–receive (T/R) front-end (FE) chip for the next-generation millimeter-wave (mm-wave) communication systems. To achieve multiband coverage in a single beamforming front-end IC, the proposed beamforming chip adopts a unified gain and phase control scheme as well as an asymmetric T/R switch circuit, which simplifies the system design and enables broadband operation in both directions. The vector-modulation-based unified phase and gain control (UPGC) scheme eliminates the standalone variable gain amplifier (VGA) in the front end. The bidirectional impedance transformation T/R switch reduces the insertion loss in the TX path and enables Class-F <tex-math notation="LaTeX">⁻¹</tex-math> operation to improve the bandwidth and efficiency. Based on the proposed UPGC scheme and T/R switch circuit, a high-performance mm-wave front-end chip is implemented using a 0.13- <tex-math notation="LaTeX">μ</tex-math> m SiGe BiCMOS technology. The fabricated front-end chip achieves 12.9–16.9-dBm maximum output power in TX mode, up to 14.3-dB gain and 7.4–9.2-dB noise figure (NF) in RX mode over the frequency range of 24–40 GHz. In both TX and RX modes, the proposed chip achieved less than 0.4-dB rms gain error and 2.0 <tex-math notation="LaTeX">∘</tex-math> rms phase error. A four-element dual-band phased array module is designed and tested to evaluate the performance of the proposed chip in the 28-and 38-GHz dual-band phased array.