Broadband gap-coupled slot cut rectangular microstrip antennas

Using the proximity feeding technique, broadband microstrip antenna has been realized by fabricating the patch on lower dielectric constant thicker substrate. The antenna bandwidth and its gain are also increased by using multi-resonator gap-coupled configurations. In this paper, broadband proximity fed pair of rectangular slot cut rectangular microstrip antenna is proposed. An analysis to study the effect of slot on broadband response is presented. The slot reduces the resonance frequency of higher order TM₀₂ mode of the patch and along with fundamental TM₁₀ mode yields broader bandwidth. Further a gap-coupled configuration of pair of rectangular slot cut rectangular patches with proximity fed slot cut rectangular microstrip antenna is proposed. The slots cut inside the parasitic patches reduces the resonance frequency of respective TM₀₂ mode, and along with the modes on the fed patch, yields bandwidth of nearly 500 MHz at center frequency of around 1000 MHz. The proposed antenna shows broadside radiation pattern over the complete bandwidth with peak gain very close to 10 dBi. Also a gap-coupled configuration of proximity fed slot cut rectangular patch with rectangular patch and slot cut rectangular patch is proposed. This configuration yields bandwidth of 530 MHz with peak gain more than 10 dBi.