A single-pole 6-throw (SP6T) antenna switch using metal-contact RF MEMS switches for multi-band applications

A single-pole 6-throw (SP6T) antenna switch using metal-contact RF micro-electro-mechanical system (MEMS) series switches has been developed for multi-band applications. The fabricated metal-contact MEMS switch with a broad signal line gap of 140 /spl mu/m shows a very high isolation loss of -51 dB at 2 GHz because its center-wedge (CW) can control a membrane stiction problem due to the anchor role. The pull-down voltage (V/sub P/) of the MEMS switch is 27.5 V and its leakage current is 26.1 /spl mu/A at V/sub P/. The SP6T antenna switch, which has six SPST MEMS switches, is comprised of two transmitter (Tx) ports and four receiver (Rx) ports for quad-band application. The chip area is very compact to 1 mm/sup 2/ (1.3 mm /spl times/ 0.8 mm). This antenna switch has an isolation loss of -48 dB and an insertion loss of -0.27 dB at 2 GHz between the antenna (ANT) port and transmitter portl (T/spl times/1) at V/sub A/ = 36V.

I. Introduction

Currently, Single-Pole Multi-Throw (SPMT) switches are widely applied in the various communication systems as they satisfactorily meet the needs of complex cellular handsets used around the world. GaAs MESFET [1] or pHEMT [2] antenna switches have been effectively used for the multi-band applications, because the switches are easily integrated with other modules and show high RF performances, such as an isolation loss or an insertion loss at lower frequency. However, the RF performances of the GaAs switches are impaired at the high frequency range due to inherent parasitic parameters such as a junction capacitance, a parasitic capacitance, or a pad resistance, as variables of a frequency function.