A Wideband Circularly Polarized Antenna Using Substrate Integrated Waveguide and Truncated-Corner Patch Loaded Slot

A wideband circularly polarized antenna based on the substrate integrated waveguide (SIW) is investigated and presented for mobile satellite applications. Initially, a rectangular-slot is etched on the top layer of the SIW cavity. A truncated patch from the one corner (top left) is loaded inside the slot to obtain the two pairs of orthogonal degenerate modes TE130/TE310 and TE230/TE320. This truncated-corner patch helps to bring the orthogonal modes closer to obtain the wideband circular polarization. Further, a rotated rectangular-slot is incorporated inside the patch to enhance the circular polarization bandwidth. The antenna exhibits a relative impedance bandwidth of 20% (10.87-3.275 GHz) and an axial ratio bandwidth 11.50-12.26 GHz (6.4%). The broadside radiation characteristics are achieved with the peak gain of 6.3dBic and 7.0dBic at the two working frequencies 11.5 GHz and 12.0 GHz respectively.