高阻硅基铝硅合金弹性膜MEMS相移器

MEMS Phase Shifter with AlSi Alloy Membrane on High-Resistivity Silicon

级联式 MEMS相移器可通过悬浮于共平面波导之上的微机械可调电容的变化 ,来改变传输线的特性阻抗和相速 ,达到相移的目的 .文中讨论了 MEMS相移器特性对微机械电容和下拉电压的要求 ,并通过轻质量的铝硅合金弹性膜 ,获得了较低的下拉电压 .测试结果表明 ,相移器的下拉电压不大于 4 0 V,且当控制电压大于 10 V时 ,即有明显的相移 .该 MEMS相移器制备于电阻率大于 4 0 0 0 Ω· cm的高阻硅衬底上 ,获得了较好的传输特性 ,在整个测试频段 1～ 4 0 GHz,S2 1 均小于 3d B,并在 2 5 V时获得了大于 2 5°的相移量 .

The design and fabrication of low loss distributed MEMS phase shifter are presented.The principle for this phase shifter is that the phase velocity can be varied by mean of snapping down the membrane of MEMS loading capacitors of the transmission line.Its MEMS capacitors and control voltage are discussed in detail.Several different membranes are used as the membranes and Al 0.96 Si 0.04 alloy shows the best performance with pulling down voltage of the MEMS phase shifter no more than 40V.There is a phase shift when the control voltage is only 10V.With the phase shifter fabricated on the high resistivity silicon( ρ >4000Ω·cm),the insert loss is very low,no more than 3dB from 1GHz to 40GHz.The phase shift will be more than 25°at 25V.