A new spiral frequency reconfigurable antenna with RF-MEMS switches for mobile RF front end

Abstract

The full-wave analyses and design of a multiband reconfigurable antenna (MRA) using radio frequency microelectromechanical system (RF MEMS) switches is presented for 1.0-10.0 GHz band. Integration of spiral antenna and MEMS switches on a conventional FR4 printed circuit board (εr = 4.4 and tan δ = 0.002) is designed. This paper also gives the construction and performance of low loss MEMS resistive switches and further describes the important improvements in the construction of the switches. The RF switches used here exhibit very good RF characteristics with typical values of pull-in voltages lies between 3.5 to 20.25 V. The cantilever beam structure of Design-3 switch offers pull-in voltage as low as 3.5 V at air gap g0 = 0.5 μm. Further, Design-1 switch have insertion losses lower than 0.39 dB in ON position, and isolation of "Design-2" switch as high as 79.83 dB in OFF position. As compared to all presented switches the "Design-3" switch has optimized displacement time response i.e. 2 ms. The effect of optimized "Design-3" switch is than study along with spiral antenna. The overall arm length of spiral is changed by activating and deactivating the three "Design-3" switches and consequently its frequency reconfigured. Finally, optimization procedure using quasi Newton method is introduced for characterizing antenna by changing slot length. The wide bandwidth ranging from 200 MHz to 1.65 GHz at different multiband of proposed MRA indicates device contribution in enhancing the mobile TV and internet application speed.