InGaAs MMIC SPST Switch Based on HPF/LPF Switching Concept With Periodic Structure

This paper presents the analysis of a novel highpass filter/low-pass filter (HPF/LPF) switching concept. Since an HPF/LPF switching concept has a periodic structure, its equivalent circuit is almost the same as an LPF for the ON-state and is the same as an HPF for the OFF-state. The broadband isolation characteristics with low insertion loss can be achieved by designing its cutoff frequency. A three-stage single pole single throw InGaAs pseudomorphic high electron mobility transistor monolithic microwave integrated circuit switch based on the HPF/LPF switching concept is successfully demonstrated with an insertion loss of less than 1.6 dB and isolation of more than 82 dB below 6 GHz, with a size of 1.1 mm × 1.0 mm. The RF performances are in good agreement with the theoretical calculations. The measured input power of 1-dB insertion loss compression, P1dB, and the measured third-order intercept point, IIP3, are 19 and 27.7 dBm, respectively, at 1.95 GHz. The measured ON-time is 5.5 ns without cable delay. The measured rise time is as fast as 1.4 ns.