Broadband dual-band stacked square microstrip antenna with shorting plates and slits

A stacked microstrip antenna with shorting plates and slits is proposed as a broadband dual-band antenna. By shorting the upper patch to the lower patch at two apexes of the diagonal of the square patch, the bandwidths (for VSWR ≤2) at the two frequency bands are enhanced and the absolute gain at the high-elevation angles at the higher-frequency band is improved. Moreover, the cross polarisation in H plane at the higher-frequency band is reduced by inserting the slits on the lower patch conductor. The proposed antenna radiates to the high-elevation angles at the two frequency bands. The measured bandwidths (for VSWR ≤2) with an absolute gain at θ = 0° ≤ dBi are 19.1 and 18.7≤ at the lower and higher-frequency bands, respectively.