Design of Dual-band Impedance Matching Circuit Using T-shape Shunt Stub

In this paper, a new dual-band impedance matching circuit is presented by using a two-section microstrip transmission line and an open-circuit T-shape shunt stub. The governing analytical relations of the structure is first obtained based on transmission lines theory. Then, by applying the matching conditions on the obtained relations, i.e. matching an arbitrary load impedance with source impedance of 50Ω at desired frequencies, nonlinear equations are generated, and solved simultaneously, meeting the electrical and physical specifications of all parts of the scheme. In order to evaluate the performance of the proposed circuit, the scheme is depicted and simulated using HFSS software. Simulation results show that the relative bandwidth of the first and the second band are 76% and 11.8%, respectively. In comparison to the previously- schemes in literature, our proposed circuit yields to a wider bandwidth and less occupied area.