High-Purity Dual-Polarized Leaky-Wave Antenna Based on Complementary Magneto- and Electric-Couplings

In this paper, complementary magneto- (M-couplings) and electric-couplings (E-couplings) are utilized to design a leaky-wave antenna (LWA) with high-purity dual-linearly polarized radiation. In detail, different excitations are used to effectively distinguish the E-couplings and M-couplings between symmetrical spoof surface plasmon polariton (S-SSPP) transmission lines and the square patch array. During the excitation of the common mode, the M-couplings between the square patch array and the S-SSPP transmission lines superpose each other. However, the cross-polarized radiation generated by the E-couplings cancels each other out. In this case, only the TM
01
mode of the square patch is excited, and the square patch array generates horizontally-polarized (H-pol) waves. Otherwise, when the differential-mode excitation implements, the E-couplings works, and only the TM
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mode is excited, which make the square patch array radiate vertically-polarized (V-pol) waves. In addition, the cross polarization levels for each polarization state are suppressed at the same time. Simulated results show that the LWA generates H-pol waves with the common mode excitation. In 11.0∽14.8 GHz band, the main beams scan from -34° to +33° with cross polarization levels lower than -45 dB. The maximum gain is 15.2 dBi. When the differential mode excitation works, the scanning range of the V-pol LWA is -51°∽+17° in 10.2∽13.8 GHz band. The maximum gain and cross polarization level are 13.9 dBi and -45 dB, respectively.