Abstract
Microstrip patch antenna is attractive for various applications due to its easy fabrication, low cost, and small size. It simply comprises a radiating patch and ground plane that are separated by a dielectric substrate. However, the resonance bandwidth of the microstrip antenna is still an issue that needs to be considered in research. This paper aims to enhance the bandwidth of a microstrip antenna or introduce more resonant frequencies within the Super High Frequency (SHF) band. The paper demonstrates empirical results for circular-shaped patch antenna using the High Frequency Structure Simulator (HFSS). It begins by investigating different patch sizes and substrate materials, so that an optimal preliminary design is introduced. Then, different slot shapes are inserted into the patch for significant enhancement of the resonance characteristics. As a result, new ultra-wideband (UWB) antenna designs are presented with bandwidth results reaching 15.5 GHz within the C, X, Ku, and K bands. Also, new multiband antenna designs are presented with improved reflection valleys in the Ku, K, and Ka bands.