A Novel Microstrip Antenna with L-Shaped Slots for Circularly Polarized Satellite Applications

A novel compact design of a circularly polarised corner-slotted microstrip antenna for satellite and synthetic aperture radar (SAR) applications is presented. A single-feed is used to excite a single-square patch with two L-shaped slots added at the upper right corner and at the opposite lower left corner (or at the other two corners) to achieve circular polarisation (CP) radiation. The proposed antenna has a simple shape, straightforward fabrication, and low cost. The impedance bandwidth (10 dB return loss) is ∼600 MHz at 8.1 GHz. An axial ratio bandwidth of 170 MHz is realised. The importance of the axial ratio 3 dB bandwidth is emphasised. In addition, an analysis for the direction of rotation of the CP is given. The experimental results have a reasonable agreement with the simulation.