Design of Square Patch Antenna with a Notch on FR4 Substrate

The simulation and experimental results of square patch antennas having a notch and designed on FR4 substrate are reported in this paper. The notch angle is varied and different radiation properties of antennas are tested. It is found that on reducing the notch angle thetas from 180deg to 164deg, the patch resonates at a single frequency. However on reducing notch angle further, the patch starts resonating at two different frequencies. The f₂/f₁ ratio almost linearly increases on decreasing the notch angle. The 10dB impedance bandwidth (VSWR 2:1) of antenna increases up to notch angle 151deg but thereafter that antenna behaves simply as a dual frequency antenna with narrow bandwidth at each resonance frequency.