Frequency-tunable PIN diode switch for software defined radio

A frequency-tunable PIN diode switch that operates at multiple frequencies is proposed for use in software defined radio and multi-band handsets. A commercially available varactor, employed in parallel with the PIN diode, is used in order to tune the operating frequency by controlling the parasitic capacitance. In single-pole single-throw and single-pole double-throw configurations, the proposed switch has a frequency band around 60% wider than that of existing alternatives with isolation of more than 20 dB. Measured and simulated results agree well. Experiments confirm isolation levels greater than 20 dB and insertion loss levels under 1 dB in the frequency band of 1.3-2.6 GHz, which covers PDC, GPS, PHS, W-CDMA and WLAN