Archimedean Spiral Slotted Leaky-Wave Antenna

Abstract

In this work, a novel leaky-wave antenna (LWA) with Archimedean spiral slots is proposed for realizing high radiation efficiency and stable gain performance in both frequency-controlled and fixed-frequency beam-scanning applications. The structural feature of the proposed Archimedean spiral slot privileges LWA with properties of easy impedance matching and high leakage rate, because it avoids the strong reflection from large-size slots that commonly used in LWA design for high leakage rate. The bandwidths of the final designed Ka-band LWA defined by radiation efficiency larger than 90% and 80% are 13% and 25%, respectively, while the bandwidth defined by return loss less than −10 dB is 29%. And the gain fluctuations between different scanned beams are less than 2.4 dBi in the whole broadband. The LWA is further applied in designing a new-type antenna with double-layer substrate-integrated waveguide (SIW) structures, which has four feeding ports at the ends and a coupling plane in the middle interface and can realize the fixed-frequency beam switching between directions of −46°, −36°, 34°, and 45° at 28 GHz through changing the excitation port. The proposed LWAs are potential candidates for applying in future millimeter wave communication systems where multifunction integrated and multifrequency adaptive antennas are required.