Study on radiation pattern of H-plane microstrip array antenna directly coupled to nonradiating edges

In order to improve directivity, a microstrip array antenna directly coupled to nonradiating edges is analysed. The equivalent circuit of the array antenna is obtained by the equivalent transmission line model and the radiation admittance parameters derived from the analysis method for the slotted parallel-plate waveguide filled with homogeneous dielectric. The calculated values of the return loss and the radiation pattern are presented and compared with the measured values. The calculated values are observed to be in fairly good agreement with the measured values.< >