A novel microstrip antenna with pre-controllable resonant frequency and impedance matching

A novel minimized microstrip planar antenna with pre-controllable resonant frequency and impedance matching is presented for microwave engineering applications. Double-sided planar structure is adopted to build the resonant loop of the antenna. The tuning of the impedance matching and the resonant frequency is studied, and the impedance matching and resonant frequency can be adjusted independently. These characteristics are validated by full wave electromagnetic simulation. A 2.4 GHz antenna for ZigBee application is designed based on the proposed structure. The simulation shows that the −10 dB bandwidth is from 2.21 GHz to 2.74 GHz with an omnibearing radiation, 2.48 dBi gain, and 35 dB return loss at the central frequency, respectively. The antenna is fabricated with a volume of 0.285λ0×0.325λ0×0.0065λ0. The measurement shows that the −10 dB bandwidth is from 2.205 GHz to 2.756 GHz, the VSWR is less than 1.04 and the return loss is better than 34 dB at 2.46 GHz.