A multi-electrode linearly adjustable mems capacitor

Abstract

Provided is a multi-electrode MEMS capacitor achieving linear adjustment. The multi-electrode MEMS capacitor comprises a medium substrate, a capacitor upper pole plate, a capacitor lower pole plate, a first anchoring point, a second anchoring point and a plurality of sets of control electrodes. The capacitor lower pole plate is arranged between the first anchoring point and the second anchoring point, the capacitor upper pole plate is arranged on the first anchoring point and the second anchoring point, and the height of the first anchoring point and the height of the second anchoring point are different. The capacitor upper pole plate is inclined. Voltage of the control electrodes is successively increased in the direction from the inclined lower end to the upper end of the capacitor upper pole plate, the voltage of the control electrodes is gradually increased, and therefore the capacitance between the capacitor upper pole plate and the capacitor lower pole plate changes in the mode approximating linearity.

Description

technical field [0001] The invention belongs to the field of radio frequency micro-electromechanical systems (RF MEMS), and in particular relates to a MEMS capacitor whose capacitance value is linearly adjustable. Background technique [0002] Radio frequency micro-electromechanical system (RF MEMS) is a radio-frequency device or system that integrates microstructure, micro-sensor, micro-actuator, signal processing and control circuit. Compared with traditional solid-state devices, it has significant advantages. Advantages, such as low power dissipation, low insertion loss, high reliability, high quality factor, etc. MEMS-based switches and capacitors are extremely important components in RF applications. Their mechanical structures can isolate control circuits and signal circuits and prevent RF signals from modulating capacitance values, so they have high linearity. [0003] Capacitive elements are widely used in MEMS-based devices, such as tunable filters, resonators, sen...

AI Technical Summary

Problems solved by technology

There are two basic forms of common MEMS adjustable capacitors. One is to adjust the spacing between the upper and lower capacitor plates to change the capacitance value. This adjustable capacitor has sensitive response, high Q value, and small size, but it has a range of spacing adjustment. Limit, the movement range of the upper plate cannot be greater than one-third of the initial distance between the upper and lower plates, otherwise the upper plate of the capacitor will be pulled down rapidly, so the adjustable range is small; the other is to adjust the facing area of ​​the capacitor to change Capacitance value, typically using an interpolated finger structure, changing the capacitance value by changing the facing area between the fingers. This structure has a complicated manufacturing process, limited capacitance value, and poor control accuracy of the capacitance.

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