In this letter, a compact dual-band absorptive single-pole double-throw (SPDT) switch design is proposed. It utilizes the bridged-T coil as a miniaturized dual-band $\lambda /4$ transformer such that the concurrent dual-band operation in the on-state and the desired absorptive property in the off-state can be both achieved. The proposed design concept is validated through a 2.45/5.8-GHz dual-band absorptive SPDT switch design implemented in a commercial GaAs pHEMT process. The measured on-state insertion loss is 1.54/1.97 dB and the off-state isolation is 35/29 dB at 2.45/5.8 GHz, while the measured return losses at all ports are better than 20 dB at 2.45/5.8 GHz. In addition, a compact chip size of 2.0 mm $\times $ 1.5 mm is achieved.
- Absorptive switch
- bridged-T coil (BTC)
- dual-band single-pole double-throw (SPDT) switch