Metal strip endfire antenna based on TE₁leaky-wave mode

In this article, the guided-wave modes and leaky-wave characteristic of rectangular metal strips are investigated to realize endfire radiation. By strategically exciting the high-order TE1 leaky-wave mode in the metal strip, a transverse in-phase E-field could be realized to generate an endfire radiation. An effective scheme is validated to manipulate the phase constant and leaky rate by altering the width of the TE1 mode metal strip. Then, to further tailor the phase constant and leaky rate for achieving an enhanced directivity, periodic grooves are etched on both edges of the metal strip to slowdown the phase velocity to a surface-wave mode. To verify this concept, an all-metal planar prototype of corrugated rectangular metal strip (CRMS) was fabricated and measured. Both the full-wave simulation and experimental results show that the CRMS could offer a high endfire gain of 14.2 dBi within a footprint of 3.0 × 0.5 λ02. Moreover, a broad overlapping bandwidth of 27.7% is realized with S11 < -10 dB, gain variation less than 3 dB, and total efficiency better than 90%. The proposed design scheme paves the way for the traveling-wave antenna with simple structure, wide bandwidth, high gain, and good platform accommodation.