Title: Apparatus for measuring impedance of a resonant structure
Application Number: 97181356 Application Date: 1997.11.13
Publication Number: 1244922 Publication Date: 2000.02.16
Approval Pub. Date: 2005.06.01 Granted Pub. Date: 2005.06.01
International Classifi-cation: G01R27/06;H03H11/04
Applicant(s) Name: Anthony Lonsdale Address:
Inventor(s) Name: Anthony Lonsdale;Bryan Lonsdale
Attorney & Agent: wang yong
Abstract:
    Apparatus for measuring the value of a physical quantity which affects the impedance of an electrically resonant structure, said apparatus comprising an electrically resonant structure, an RF electrical energy source, a bidirectional RF transmission line connecting said source to said resonant structure, a directional coupler associated with said transmission line, said source providing an excitation signal to said structure, said directional coupler detecting the voltage or phase of a reflected signal returned from said resonant structure characterised in that the resonant structure is substantially non energy radiating and, at a given frequency of said source, has an impedance which varies continuously as a function of the value of said physical quantity. Typically the electrically resonant structure is at least partially composed of piezoelectric material.
Time: 18
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