A circularly polarized square microstrip parasitic antenna with an improved bandwidth

This paper presents a novel design for an optimized circularly polarized microstrip antenna. Circular polarized microstrip antennas have many uses due to its low profile design. However, one of the microstrip antenna's main limitations arises from its narrow frequency bandwidth. Therefore, it is necessary to use special design techniques in order to increase the operating frequency bandwidth while maintaining all of the other respectable optimum radiation characteristics. The proposed design involves using a dual-feed square patch, which is gap coupled with two parasitic patches in a mirrored L-shaped configuration. This design resulted in an axial ratio bandwidth of 11%, S11 bandwidth of 14% and a gain of 9 dB at the 2.15 GHz center frequency. The proposed design was built, and the measured results were in agreement with the simulation results. Additionally, this antenna design was used in an array structure in order to increase the gain, while maintaining a good axial ratio. These enhanced radiation results allow the use of the proposed antenna design in many domains such as wireless and military applications without facing the limitations of the narrow frequency bandwidth. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:597-603, 2016