C‐band high purity circularly polarized array with modified radial slots and electromagnetic band‐gap substrate configuration

Novel broadband circularly polarized (CP) electromagnetic band‐gap (EBG) antenna array was proposed in this paper. The antenna's radiating element is utilized by a microstrip‐fed circular patch, radial slot, and three rectangular notches. The proposed antenna elements are fed by feeding network comprised form four hybrid couplers and microstrip lines with appropriate lengths to support desired phase difference at output ports. Radiating patches are sequentially rotated to enhance CP property and form a 4 × 4 array. Finally, the novel scheme of electromagnetic structure (EBG) was inserted among radiating elements to decrease the mutual coupling. Using these structures results in the improvement of antenna bandwidth to cover the entire C‐band. In addition, CP purity is increased at the implicational band. Measured results indicate that the array has an impedance bandwidth of 4 GHz covering the C‐band totally and 3 dB axial‐ratio bandwidth of 2.6 GHz that is between 4.9 and 7.5 GHz (~42%). The antenna array has a peak gain of 8dBi at 6 GHz.