Design of a wideband antenna by manipulating characteristic modes of a metallic loop

摘要

A wideband antenna is designed by manipulating characteristic modes (CMs) of a metallic loop structure. It is shown that the resonant behavior of the CMs can be modified by inductive loading on the specific positions of the loop antenna. Therefore, it is possible to manipulate certain modes to ensure their resonant frequencies are close to each other. Then, a proper feeding scheme can be designed such that these modes are excited simultaneously and a multi-mode wideband antenna can be obtained. It is found that by using the theory of characteristic modes (TCMs), the antenna design procedure becomes more intuitive. To validate the proposed approach, the wideband antenna was fabricated and tested. Simulation and measurement results indicate that it can achieve a wide impedance bandwidth of 51.6% with |S-11| -10 dB.