Patent ID: 7821273
Filing Date: 2010-10-26
Classification: G01R,H03H,H04B

Abstract:
1. A circuit for detecting an impedance or an admittance of a radio frequency or microwave load, comprising: a directional coupler having input terminals connected to a radio frequency or microwave amplifier and connected to the load; the directional coupler having a first output terminal connected to a first peak detector for measuring a magnitude of a voltage or a magnitude of a current of a forward wave, wherein the first peak detector comprises a first mixer and a first amplitude limiter, and wherein the forward wave is inputted to a first input port of the mixer, and the forward wave is also inputted to the amplitude limiter, and the output of the amplitude limiter is inputted to a second input port of the mixer; the directional coupler having an second output terminal connected to a second peak detector for measuring the magnitude of a voltage or a magnitude of a current of a reflected wave, wherein the second peak detector comprises a second mixer and a second amplitude limiter, and wherein the reflected wave is inputted to a first input port of the second mixer, and the reflected wave is also inputted into the second amplitude limiter, and the output of the second amplitude limiter is inputted to a second input port of the second mixer; and a quadrature phase detector being arranged to output signals providing information on the phase θ of the reflection coefficient Γ within a range of 0° to 360 °.