Broadband proximity-coupled microstrip antennas with an H-shaped slot in the ground plane

To improve the inherently narrow bandwidth of a microstrip antenna, it is very effective to use an electrically thick (∼0.1λ₀) substrate. A microstrip-line feed together with a slotted ground plane can add degrees of freedom in the design of the antenna feed. A proximity-coupled microstrip antenna with an H-shaped slot in the ground plane is investigated experimentally. The impedance bandwidth of the microstrip antenna is shown for various substrate thicknesses. Also, the backward radiation of the antenna is presented and discussed. Due to the advantages of simplified configuration and low cross polarization, the proposed antenna is also suitable for application in array antenna design.