Experimental Investigation on Mode Isolation Enhancement for 28 GHz OAM Circular Antenna Arrays by Dielectric Loading

In this paper, we experimentally study an effect of dielectric loadings in OAM antenna arrays on the isolation characteristics. Cylindrical dielectrics with the permittivity of 2.6 are loaded in TX/RX circular 8-element OAM antenna arrays designed at 28 GHz, and OAM mode isolation characteristics are measured in an anechoic chamber. It is confirmed that the isolation characteristics are enhanced by 3.2 dB in the broad frequency range in the 28 GHz band with the optimized dielectric cylinder loading.