Variable capacitor, impedance matching device, mobile terminal thereof and method for matching impedance

摘要

Disclosed is an impedance matching device. Variable devices of the impedance matching device installed in a mobile terminal, such as a portable terminal, are configured to have a MEMS structure. The MEMS structure and other components are integrated as one package, so the manufacturing cost is reduced and the manufacturing efficiency is improved.

主权项

1. An impedance matching device comprising:
a substrate; a variable device unit mounted on the substrate and including at least one MEMS variable capacitor to change a capacitance value according to applied voltage; a fixed device unit mounted on the substrate and including at least one inductor coupled with the MEMS variable capacitor to form a predetermined time constant; a reflective power measurement unit mounted on the substrate to measure an intensity of a reflective wave of a signal transmitted from the variable device unit and the fixed device unit; and a converting unit mounted on the substrate to output a direct current voltage value by converting the intensity of the reflective wave of the signal measured by the reflective power measurement unit into the direct current voltage value; wherein the MEMS variable capacitor comprises:
a first electrode;a second electrode floating above the first electrode;a fixed electrode spaced apart from a lateral side of the second electrode; anda movable electrode interposed between the second electrode and the fixed electrode and connected to the second electrode to physically make contact with the fixed electrode as voltage is applied to the fixed electrode; and wherein a first insulating layer is formed on the first electrode to inhibit an electrical short between the first electrode and the second electrode, and a second insulating layer is formed on the fixed electrode to inhibit an electrical short between the fixed electrode and the movable electrode.