Quasi-planar Composite Microstrip Antenna: Symmetrical Flat-Top Radiation with High Gain and Low Cross Polarization

In this paper, a quasi-planar composite microstrip antenna consisting of a single layer rectangular microstrip antenna along with two metallic posts (monopoles) has been studied theoretically and experimentally. The proposed antenna exhibits wide, symmetrical radiation (around 145°) in both principle planes, along with flat-top radiation in the entire bore sight region (72° along with bore sight) with high gain (8.5 dBi) and significantly low cross polarized radiation. More than 26 dB co-cross polarization isolation over an entire broadside direction is obtained. The present structure is very simple and easy to manufacture. The present investigation provides an insightful, visualization-based understanding of concurrent improvement of the radiation characteristics.