Impact of a square grounded dielectric substrate on the radiation characteristics of a rectangular microstrip patch antenna

The radiation characteristics of a rectangular microstrip patch antenna with a square grounded dielectric substrate are investigated. Effect of the substrate size on the resonant frequency and bandwidth is very small, while that on the radiation pattern is large. As the thickness of a substrate increases, the variations of the broadside radiation and the direction of a peak gain increase due to the increase of surface waves. A rectangular microstip patch antenna with a square grounded dielectric substrate size of 0.8 lambda₀ gives the large broadside radiation and largest difference between the broadside radiation and the back radiation.