Key Technology of Mixed Matching Circuit for Miniaturizing Dual-Band Antenna

A mixed matching circuit for miniaturizing dual-band antenna is introduced and verified in this study. Two L-shaped matching circuit for miniaturization are cascaded to interpret the theory of operation in accordance with the dual-band allocations on the Smith chart. A matching circuit equation is deduced based on a bidirectional matching track from a certain position to the origin point on the Smith chart. Furthermore, a dual-band antenna is taken as an example to illustrate the performance of the novel matching approach for miniaturization. The occupation of a dual-band antenna can be reduced by a quarter at the simultaneous operational frequencies of 2.4 and 5.8 GHz. Lastly, a dual-band planar inverted-F antenna (PIFA) is developed and examined. The experimental results are well consistent with those in the simulator.