A Broadband Circularly Polarized Antenna with Top-Loaded Artificial Dielectric Layers

A miniaturised broadband circularly polarized antenna working at Ka-band is proposed. The circular polarization of the antenna is achieved well by feeding the signal through two orthogonal probes. The broadband impedance transformation of the antenna is realised with free space through artificial dielectric layers (ADLs) loaded on the top, thus broadening the bandwidth of the antenna. The simulation results show that the impedance bandwidth of the antenna is 26.94 GHz37.55 GHz with a relative bandwidth of 33.41%, and the axial ratios within the bandwidth are all less than 3 dB. Meanwhile, an 8 × 8 array is formed by means of rotating feed, and the impedance bandwidth of the cells in the array is 29.87 GHz-38.85 GHz with a relative bandwidth of 26.13%. The above results have shown that this broadband circularly polarized antenna with an artificial dielectric layer carried on top has good application prospects in the field of communication.