A High-Power SPDT Switch With Resonant Isolation Based on GaAs BiFET Technology for Sub-6-GHz Front-End Modules

초록

In this study, we present the design of a single-pole double-throw (SPDT) switch for Sub-6 GHz applications, implemented using a 500-nm GaAs BiFET process. To enhance power handling capability, multi-gate transistors are selectively employed. The frequency characteristics of return loss, insertion loss, and isolation are analyzed through an equivalent circuit model. Based on this analysis, we propose a design methodology that optimizes transistor on-resistance and parasitic capacitance for the target frequency range, thereby improving power handling, insertion loss, return loss, and isolation. The fabricated switch is evaluated across an operating frequency range of 3.0-5.0 GHz. In Tx mode, the input P ${}_{1dB}$ exceeds 38.1 dBm at 4.0 GHz. The measured insertion loss and isolation in Tx mode are below 0.38 dB and above 36.6 dB, respectively. In Rx mode, insertion loss remains below 0.38 dB, while isolation exceeds 35.0 dB.

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