Piezoelectric type two-block cascaded micro mechanical filter

Abstract

The invention belongs to the original device technical field in the radio frequency communication and micro electro mechanical system (MEMS) technical field and provides a piezoelectric type two-block cascaded micro mechanical filter. The piezoelectric type two-block cascaded micro mechanical filter includes two vibration blocks with the same size, a coupling beam, supporting beams, supporting stages, an input electrode, an output electrode, direct current bias electrodes, piezoelectric film layers and an insulating substrate; the two vibration blocks are connected with each other through the coupling beam; the two vibration blocks are also connected with the supporting stages through the supporting beams which are fixed at the middle point of one side edge of each vibration block respectively; the two vibration blocks are arranged on the insulating substrate in a suspension manner; the vibration blocks are covered with one piezoelectric film respectively; the input electrode and the output electrode are arranged on the piezoelectric films respectively; one pair of direct current bias electrodes surround the two vibration blocks; and the direct current bias electrodes and the vibration blocks form a capacitance structure. According to the piezoelectric type two-block cascaded micro mechanical filter of the invention, a piezoelectric structure is adopted, and the filter can be formed through the coupling of the two vibration blocks, and therefore, the piezoelectric type two-block cascaded micro mechanical filter has the advantages of simple and compact structure, reduced processing difficulty, high coupling efficiency, high Q value and better sharp cut-off.

Description

technical field [0001] The invention belongs to the technical field of components in the technical field of radio frequency communication and micro-electromechanical systems (MEMS), and in particular relates to a micro-mechanical filter formed by coupling two completely identical piezoelectric micro-mechanical resonators. Background technique [0002] With the further requirements of high performance and miniaturization of electronic equipment, electronic components are developing in the direction of high performance, low cost and low power consumption. High Q value, miniaturized resonators and filters become the bottleneck of on-chip and miniaturized electronic communication systems in the future. The RF MEMS filter is a high-performance RF filter device based on mechanical vibration made using MEMS technology. The input electrical signal is converted into mechanical vibration through electromechanical coupling. The filtering function is completed in the mechanical domain, ...

AI Technical Summary

Problems solved by technology

Therefore, due to the capacitive structure of the capacitive filter, its structure is more complicated than that of the piezoelectric filter, and the processing process is more complicated and difficult.

At the same time, capacitive filters must be loaded with a DC bias to work, and the efficiency of energy conversion is lower than that of piezoelectric filters.

At present, the research on piezoelectric filters is not particularly mature. The types of piezoelectric filters that have been studied are relatively small, and the bandwidth of piezoelectric filters is relatively narrow. For the adjustment of the center frequency and bandwidth of the filter are not very flexible

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