关键词: 砷化镓(GaAs), 正电压控制开关, 单刀双掷开关(SPDT), 低损耗

Abstract: To address the challenges of complex power supply requirements and excessive chip area occupied by large DC-blocking capacitors in conventional negatively biased GaAs pseudomorphic high electron mobility transistor (pHEMT) single-pole double-throw (SPDT) switches, this paper proposes a novel 0.1-2.5 GHz SPDT switch topology based on a 0.25 μm GaAs pHEMT process with positive-voltage control. The design introduces series inductors in the RF signal paths to form resonant networks with the parasitic capacitances of the transistors, thereby effectively reducing insertion loss. DC-blocking capacitors are employed to suppress unwanted DC leakage, while bias resistors establish a +5 V source potential, enabling the gate-source voltage(V_gs) of depletion-mode transistors to be modulated using a single positive control voltage. Measurement results demonstrate that, compared to conventional negative-voltage-controlled counterparts, the proposed design eliminates the need for negative biasing, significantly reduces the footprint of DC-blocking capacitors, and achieves an isolation greater than 14.08 dB. These results verify the advantages of the positive-voltage architecture in terms of simplified biasing, reduced loss, high isolation, compact layout, and high integration capability.

Key words: gallium arsenide (GaAs), positive voltage control switch, SPDT switch, low loss