Impedance Matching of Time-Variant Transponders

Abstract

Impedance matching is a wide spread concept in engineering, mainly employed to analyze the transfer of energy. In the most common case, the matching is used to maximize the power transfer between the source and the load. This matching is known as complex conjugate matching. However matching in the case of variable load impedance value remains an open problem. In this paper, three matching methods are proposed for linear time-varying systems (i.e., where the load impedance value is a function of time). All three matching methods allow one to determine the (fixed) source impedance value to either maximize the power dissipated into the load, minimize the static power reflected to the source or maximize the modulated power reflected to the source. These matching conditions are fundamentally different compared to the “averaged” conjugate matching.