Compact CRLH Leaky-Wave Antenna Using TE 20-Mode Substrate-Integrated Waveguide for Broad Space Radiation Coverage

Abstract

In this communication, a composite right-/left-handed (CRLH) based four-quadrant dual-beam scanning leaky-wave antenna is proposed and demonstrated using substrate-integrated waveguide (SIW) technology. The simultaneous use of dual-radiating sections of the TE20-mode SIW makes the structure quite compact with the enhancement in overall gain as compared to the TE10-mode SIW. In addition to this, the incorporation of interdigital slots on the top as well as the bottom plates of the waveguide enables the feature of CRLH media, resulting in full-space beam scanning. Based on the orientation of the electric field on the guiding structure, the top and bottom slots are orthogonally placed to each other. The unit cell characteristics and space harmonics are thoroughly investigated using the dispersion and Bloch impedance analysis. By tactfully tuning the design parameters, the balanced condition is obtained at the broadside frequency of 11.5 GHz. The radiated dual beam covers a four-quadrant scanning range of 248°, having the beam steering from -75° to 49° for both top and bottom halves of the space. The proposed antenna operates within 10-12.8 GHz with a peak gain of 18 dBi. The designed antenna is finally fabricated and tested, where the simulated responses are found in good agreement with the corresponding measured data.