A Holographic Antenna Approach for Surface Wave Control in Microstrip Antenna Applications

A holographic antenna inspired structure is used to control the surface wave (SW) excited by a microstrip patch antenna. The hologram is designed to support a periodic leaky-wave which radiates at broadside and enhances the radiation of the patch while suppressing the horizontal lobe. In this design, the holographic approach is adapted for patch antenna applications where the SW wavelengths are comparable to the freespace wavelength. This is achieved by introducing dual phase-shifting metallic dipoles with periodic spacings. This paper discusses a simple and intuitive design method for the holographic surface, as well as its integration with the microstrip patch. The initial design concept was developed by assuming small perturbation to the SW, which was subsequently verified through full-wave simulations and prototype measurements. The results verified the improvements in the broadside gain and SW efficiency of the microstrip patch at the cost of increased area.