Square Microstrip Antenna Using U-slots For Circular Polarized And Wide band Response

Design of square microstrip antenna using two pairs of unequal length U-slots is presented for circular polarized and wideband response. The U-slots in square patch optimizes the spacing between patch fundamental orthogonal TM10 and TM01 resonant modes that yields axial ratio bandwidth of 42 MHz in 950 MHz frequency spectrum. The U-slots reduces the resonance frequencies of higher order TM11 and TM02 modes and optimizes the current contribution at same which gives VSWR bandwidth of above 650 MHz (>55%). Across the axial ratio and VSWR bandwidth antenna offers broadside radiation pattern. At center frequency of axial ratio bandwidth proposed antenna offers peak broadside gain of around 8 dBi. The proposed circular polarized design of square patch with U-slots can find applications in wireless mobile and personal communication applications in 950 MHz frequency spectrum.