Wideband Dual Circularly Polarized CRLH Leaky-Wave Antenna Using Half-Mode SIW

초록

This paper presents a dual circularly polarized (CP) composite right/left-handed (CRLH) leaky-wave antenna (LWA) based on half-mode substrate-integrated waveguide (HMSIW). The proposed LWA consists of six cascaded unit cells. In each unit cell, interdigital capacitors are connected to the left and right sides of the patch to provide a series left-handed capacitance, while four vias on the upper side of the patch create a shunt left-handed inductance. The operating principle of the proposed LWA is analyzed by examining the relationships among the wavenumbers, as well as the mechanism responsible for generating dual circular polarization. The performance of the proposed LWA was validated through fabrication and measurement. Measured realized gains of 14 dBic and 14.75 dBic were achieved when Port 1 and Port 2 are excited, respectively. The LWA operates over 4.75 − 6.75 GHz and provides continuous beam scanning from −35◦ to +35◦. In addition, circular polarization is maintained with an axial ratio below 3 dB over the 5 − 6.75 GHz bandwidth. These features make the proposed antenna well-suited for frequency-modulated continuous-wave (FMCW) radar applications requiring fine range resolution, beam scanning, and polarization diversity. © 1963-2012 IEEE.

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