Artificially anisotropic substrate with aperture-coupled feeding for generating circularly-polarized antenna solutions at mmWaves

In the present paper, the design of an artificially anisotropic substrate (AAS) with an aperture-coupled feeding structure is proposed for the generation of circular polarization (CP) at 28 GHz. The radiator configuration is constructed by assembling thin sheets with different relative permittivities as a stack for generating different effective permittivities for the wave components. It is demonstrated that by using sufficient high inclusion permittivity material together with material close to air, the AAS is observed to show AR <; 2 dB with 25 dBi higher RHCP gain than LHCP. The proposed radiator configuration provides excellent polarization purity in addition to opportunity to be integrated close to other electrical RF components in transceiver to avoid strong wiring losses at mmWaves.