Dual Polarization and Dual Beam Elliptical Waveguide Leaky Wave Antenna

This paper presents a novel elliptical waveguide leaky wave antenna (EWG LWA) with dual beam and dual polarization, which can be used in 2×2 multi-input multi-output (MIMO) system. The antenna works on two spatial harmonic waves (u ϵ [0, -1]) simultaneously to generate two radiation beams respectively. Through the detailed theoretical derivation of radiation E-field based on the two-±45º-slot unit on the EWG LWA, the polarization of the beam of the EWG LWA can be controlled. By utilizing two-±45º-slot unit with a spacing of a half period, the two beams have orthogonal polarizations. Then the system achieves both spatial and polarization diversity, significantly enhancing channel capacity and robustness, enabling higher data rates for modern indoor communication systems. For verification, an EWG LWA with 5 two-±45º-slot units centered at 5.5 GHz is designed. The impedance bandwidth with |S11| < -10 dB is over 14.5%. The peak gains of beams 1 and 2 are 7.4 dBi and 5 dBi, respectively.