Planar center-fed leaky-wave antenna arrays for millimeter wave systems

Two kinds of planar center-fed leaky-wave antenna arrays for millimeter wave systems are presented. The antenna arrays consist of a printed one-dimensional periodic metal strip grating on a grounded dielectric waveguide and designed for broadside radiation. The first antenna array has a hybrid structure with a feeding device for the planar dielectric waveguide, represented by a center-fed linear slot waveguide array. The second antenna array has a simple single-layer structure with a feeding device, formed by a comb line using the central strip of the grating. The investigated examples of both kinds of arrays exhibit low return loss at frequencies of broadside radiation. The radiation efficiency of antennas exceeds 50 % at frequencies of up to 37-37.5 GHz, while the antenna gain is above 30 dBi.