| CPC H03H 9/64 (2013.01) [H03H 9/25 (2013.01); H03H 9/58 (2013.01)] | 9 Claims |
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1. A method of preparing a radio frequency filter, comprising:
forming a resonant structure on a front surface of a substrate;
forming a supporting electrode on the front surface of the substrate based on the resonant structure; and
forming a thin film structure spaced with the substrate by the supporting electrode,
wherein the forming the supporting electrode on the front surface of the substrate based on the resonant structure comprises:
forming a sacrificial layer on the front surface of the substrate;
forming a seed layer on the sacrificial layer; and
forming the supporting electrode on the seed layer based on the resonant structure; and
wherein an end face of a top end of the supporting electrode is in sealing contact with a front surface of the thin film structure, and the supporting electrode comprises:
a first supporting electrode protruded on an edge of the front surface of the substrate with respect to the substrate, while the first supporting electrode is of an annular closed structure surrounding the edge of the front surface of the substrate; and
a plurality of second supporting electrodes, each second supporting electrode of the plurality of second supporting electrodes is protruded on a middle portion of the front surface of the substrate with respect to the substrate in a certain distribution, while the plurality of second supporting electrodes are surrounded by the first supporting electrode on the middle portion of the front surface of the substrate.
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