VARIABLE CAPACITANCE MEMS VARACTOR ARRAY METHOD & APPARATUS

摘要

Impedance between an antenna and a power amplifier in a cell phone is dynamically matched by selectively increasing the potential difference between a bias electrode and a top plate to move the top plate to a down position for a number of varactors needed to change the capacitance and bring about the match. Each varactor has a capacitor bottom plate formed on the substrate to include the bias electrode, a ground electrode and an RF signal line electrode. A capacitor top plate is suspended by mechanical spring action above the bottom plate for movement between an up position and a down position relative to dielectric material covering the bottom plate. The potential difference applied between the bias electrode and the top plate can be selectively increased to overcome the spring action and move the top plate to the down position, shunting an RF signal applied at the RF signal line electrode to ground through the top plate.