Parasitic Gap Coupled Microstrip Patches with Slot for Broadband Performance

Abstract: This paper presents the radiation performance of stacked arrangement of square microstrip patches. The lower patch (driven patch) is modified by inserting two narrow slots at two opposite corners of square patch while the stacked upper patch is a conventional square patch. Both patches are identical in dimensions. These patches are prepared on glass epoxy FR-4 substrates and are separated through an air gap. The simulation analysis is carried out by using method of moment based IE3D simulator. The optimization of slot lengths, width, angles and applied air gap of proposed arrangement is carried out to achieve much improved bandwidth (44.16%). With proposed feed arrangement, antenna also displays right circular polarization. In the range of frequency where antenna is displaying broadband performance, radiation patterns are identical in shape with direction of maximum intensity inclined at an angle 45o with plane of patch. The free space performance of this arrangement of patches is compared with that of a stacked arrangement of conventional square patch antenna of identical size.

Keywords: Microstrip antenna, circular polarization, broadband, axial ratio