Polarization and bandwidth improvements of a zeroth-order resonators loaded microstrip antenna with grid polarization filter cover and metallic cavity

In this research, the polarization and bandwidth of a zeroth-order resonators (ZORs) loaded microstrip antenna are improved by employing a grid polarization filter cover and a metallic cavity. The polarization improvement is owing to three operations, (a) the filter cover allows co-polarization wave passing through only, (b) the ZORs partly rotate the reflected cross-polarizations (X-polarizations) wave to be co-polarization, (c) the metallic cavity suppresses the fringe fields of the cover. The bandwidth enhancement is owing to the polarization cover that reflects theX-polarization, which forms a resonant cavity. The improvements of the simulated cross-polarizations range from 17.7 to 35.3 dB in the band. The measured bandwidth is increased from 940 MHz (17.22%) of the referenced antenna to 1390 MHz (24.5%) of the proposed antenna. The measured results verify the simulations.