Frequency Reconfigurable U-Slot Microstrip Patch Antenna

A frequency reconfigurable microstrip patch antenna is presented. It is found that the incorporation of a U-slot in the patch can provide a flat input resistance and a linear input reactance across a wider bandwidth than the conventional patch antenna. By placing a variable capacitor and an inductor at the antenna input, the impedance matching frequency of the antenna can be varied. The fabricated prototype antenna attains a tunable frequency range from 2.6 to 3.35 GHz. The proposed antenna is simple in structure, and the control circuitry is placed underneath the ground plane. It is suitable for use in reducing the crosstalk from adjacent channels in multichannel system.