Filter element, and filter device having same, duplex and high-frequency circuit

Filter element, and filter device having same, duplex and high-frequency circuit

  • CN 1,503,451 B
  • Filed: 11/21/2003
  • Issued: 04/18/2012
  • Est. Priority Date: 11/22/2002
  • Status: Active Grant
First Claim
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1. filter element comprises:

  • A plurality of resonators;

    It is arranged in the series arm and parallel branch of circuit;

    Each resonator in said a plurality of resonator comprises single piezoelectric membrane and is arranged on top electrode and the bottom electrode on the apparent surface of said single piezoelectric membrane;

    Said single piezoelectric membrane is public for said a plurality of resonatorsSaid a plurality of resonator comprises the series arm resonator and the parallel branch resonator of the series arm and the parallel branch of the first order that is arranged on the signal input side;

    In said series arm resonator and the parallel branch resonator at least one comprises single-ended pair of piezoelectric thin film vibrator of a plurality of parallel connections;

    The quantity of said single-ended pair of piezoelectric thin film vibrator is n, and n is the integer more than or equal to 2;

    The size of the driver unit of each in said a plurality of single-ended pair of piezoelectric thin film vibrator is the 1/n of driver unit with another single-ended pair of piezoelectric thin film vibrator of the impedance that equates with the total impedance of said a plurality of single-ended pair of piezoelectric thin film vibrators;

    Said driver unit is such zone;

    Be clipped between said top electrode and the bottom electrode at single piezoelectric membrane described in this zoneSaid filter element also comprises series arm and/or the parallel branch that only comprises a single-ended pair of piezoelectric thin film vibrator.

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