Reconfigurable RF impedance tuner for match control in broadband wireless devices

This paper presents the design of a broadband RF impedance tuner that is part of a dynamically reconfigurable automatic match control (AMC) circuit that can be used for a wide variety of wireless devices and intelligent RF front ends. The impedance tuner can be used at the input of wireless devices in order to provide a significantly broader bandwidth or to reconfigure the impedance match spectrum. The tuner uses a microstrip loaded-line circuit topology with multiple stubs that each have a varactor diode located at the end. The results show that the tuner can achieve a broadband impedance match for a wide variety of loads that are either purely resistive or that have a large reactance as well.