Orthogonally Dual-Polarized Leaky-Wave Antenna for Endfire Radiation Based on Periodical Loading

We propose a dual-polarized leaky-wave antenna (LWA) with orthomode based on a metallic square waveguide for broadband endfire radiation applications. Several double-sided slots acting as radiation elements are notched on the waveguide to produce an endfire pattern. To overcome the restriction associated with the endfire radiation condition of a linear array, a metallic core periodically loaded with pins is used to control the dispersion of the proposed double-sided-slot waveguide. By optimizing the height distribution of the loading pins along the longitudinal direction using a cosine function, stable endfire radiation can be achieved over a broad operating band. Moreover, dual-polarized radiation can be automatically implemented because of the rotational symmetry of the proposed LWA. Furthermore, two rectangular waveguides connected with a square waveguide are used as the orthomode transducer (OMT) of the proposed LWA. The numerical and experimental results verify that dual-polarized endfire radiation is achieved in the frequency range of 7.6-9.1 GHz with an isolation of higher than 45 dB. The realized gain achieved is in the range of 13-15 dBi with a cross-polarization level of below-30 dB.