Circularly polarized electromagnetically coupled stacked variation of corner-truncated square microstrip antennas

An electromagnetically coupled stacked configuration of square microstrip antennas with truncated corners are proposed for circularly polarized radiation response in GPS L5 and L2 bands. The corner truncation achieves degenerated fundamental diagonally directed radiated resonant modes on the square patch, achieving circular polarized characteristics. The axial ratio bandwidth of the proximity fed square patch with truncated corners on a 2.56 cm thicker substrate is 71 MHz (5.89%), falling within the 417 MHz (34.11%) bandwidth. The antenna exhibits more than 8 dBic gain over the axial ratio bandwidth in broadside direction, thus satisfying the gain and bandwidth requirement of GPS L5 and L2 band applications. A multi resonator stacked design of two corner truncated square microstrip antennas is presented to enhance the axial ratio bandwidth. Within a 403 MHz (33.62%) reflection coefficient bandwidth, the stacked design attains an axial ratio bandwidth of 73 MHz (6.26%). Antenna realizes more than 8 dBic broadside gain along the axial ratio bandwidth. With observed antenna characteristics, the electromagnetically coupled designs can be useful in GPS L-bands, and its equivalent designs can be useful in Galileo E1 and E6 bands. In the two proposed configurations, experimental validation has been carried out, which shows good matching with the outcomes of the simulation.