A Switchable Matching Circuit for Compact Wideband Antenna Designs

A novel compact wideband antenna, which adopts a multi-state switchable matching circuit, is proposed in this paper. The design of the switchable matching is systematically studied and a two-step iterative procedure is used to obtain optimized values for both the bandwidth division between the various stages and the matching circuit components in each stage. Without loss of generality, a meander line monopole, with dimensions of 80 10 10 , is used as the radiator in the proposed wideband antenna design. To validate the proposed new design, a four-state matching circuit controlled by four PIN diodes is fabricated and measured. The reflection coefficient of the prototype antenna is found to be better than , and the peak gain is higher than across the 470-770 MHz bandwidth for the Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) application.