A Multi-Beam Planar Leaky-Wave Antenna for W Band Radar Systems

This article presents a multi-beam planar leakywave antenna designed for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{W}$</tex>-band radar systems. T-shaped and thin angled-ended slots are introduced into the circular seriesfed patch array structure to enhance impedance matching and enable multi-beam functionality. The antenna operates in the 78.5 GHz to 88 GHz range, achieving a bandwidth of 11.4 %, an average gain of 12 dBi, and a total efficiency of 80 % or higher. It provides total beam scanning of 63° across the ranges of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-78^{\circ}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-44^{\circ},-15^{\circ}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-1^{\circ}$</tex>, and 27° to 42°, utilizing triple main beams. To the best of the authors' knowledge, this is the first study of a planar multi-beam leaky-wave antenna with a simple feeding for W-band applications. The antenna's planar design, simplicity, high efficiency, and multi-beam capability make it an excellent candidate for SAR imaging in airborne applications and automotive radar systems operating in the W-band.