Broadband Gap-Coupled Slot Cut Rectangular Microstrip Antennas

The broadband microstrip antenna is more commonly realized by using multi-resonator gap-coupled technique or by cutting the slot inside the patch. The gap-coupled configuration increases the antenna size whereas the slot cut designs maintains the low profile nature of the antenna and also adds to the bandwidth. The slot is said to introduce a mode near the fundamental mode resonance frequency of the patch and increases the bandwidth. In this paper, broadband proximity fed E-shaped microstrip antenna is discussed. The gap-coupled configuration of E-shaped antenna with rectangular microstrip antennas is proposed. This gap-coupled configuration gives a bandwidth of 450 MHz at center frequency of around 1000 MHz with broadside radiation pattern and gain of more than 7 dBi over the bandwidth. Further gap-coupled configuration of pair of rectangular slot cut rectangular patches with E-shaped antenna is proposed. This configuration yields a bandwidth of more than 550 MHz with broadside radiation pattern and peak gain very close to 9.5 dBi.