A 28 GHz Interleaved Circular Antenna Array with Equal Gains and Wideband Orthogonality for Analog OAM Multiplexing

We propose interleaved circular array antennas generating ±1 orbital angular momentum (OAM) beams with equal gains and wideband orthogonality for analog OAM multiplexing in wireless communication. The antenna array is designed and implemented at 28 GHz band. It is shown that the wideband orthogonality of these OAM modes with the 3dB isolation bandwidth of as wide as 6.1 GHz from 24.9 to 31 GHz. The equal gain main beam characteristics are also shown experimentally with the wideband return loss characteristics.