High-Scanning-Rate and Wide-Scanning-Angle Leaky-Wave Antenna Based on Double-Layer Slow-Wave Structure

In this letter, a leaky-wave antenna (LWA) based on double-layer (DL) slow-wave structure, possessing high-scanning rate and wide-scanning angle features is investigated. The DL unit structure consists of a top-layer structure with cross-shaped unit and a bottom-layer structure with slot-shaped unit. The DL units realize the property of controlling the cutoff frequency and slope of dispersion curves independently by independently changing the unit slow-wave property of top and bottom layers. The radiation of LWA is achieved by triangularly modulating the cross-shaped units of top layer. Due to the existence of the slot-shaped units of bottom layer, strong slow-wave property is introduced to increase the growth rate of period phase shift, thus achieving high-scanning rate. Meanwhile, the n = −2 space harmonic (SH) of the LWA is separated from the fast-wave region of n = −1 SH, thus enlarging scanning angle in forward quadrant. A prototype of the proposed LWA is fabricated and measured. The LWA can achieve a wide-scanning angle from −68 ° to +74 ° in a narrow frequency band of 9 to 10.75 GHz.