Patent ID: 9680217
Date: 2017-06-13
CPC Classifications: H01Q,H03H

Claim:
1. A radio frequency (RF) receiver comprising: an antenna having a feed point; a tunable matching network connected to the antenna feed point to receive RF signals from the antenna; power detector, connected to point to the RF receiver, to measure at the single node power levels of the received RF signals output from said feed point; and a control system that calculates values of tuning elements of the tunable matching network to match an input impedance of the antenna at the feed point by using at least three power level measurements simultaneously in two non-linear equations, the at least three power level measurements being detected at said single node by said power detector, wherein a first non-linear equation of the two non-linear equations is formulated as: is the ratio of power received by the reactive elements of the matching network; S 22 (1) is a scattering matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input after a first perturbation of the matching network; S 22 (0) is a matrix parameter that represents an output reflection coefficient of a 50 ohm terminated input in a previous tuning period; S 21 (0) is a scattering matrix parameter which represents the forward transmission coefficient of a 50 ohm terminated output in a previous tuning period; Γ L is a reflection coefficient of the load, and Γ in (0) is an input reflection coefficient of the matching network as seen from the antenna in a previous tuning period; Γ in (2) is an input reflection coefficient of the matching network as seen from the antenna after a first perturbation of the matching network; and Γ A is a reflection coefficient of the antenna.