Highly Integrated Beam Scanning Groove Gap Waveguide Leaky Wave Antenna Array

In this communication, a novel 2-D beam scanning antenna array is designed and fabricated in metallic 3-D printed technology with high integration and reduced fabrication complexity in millimeter waves. The array is composed of four leaky wave antennas and a Butler matrix based on groove gap waveguide (GWG) technology. One dimension of the beam scanning performance is realized by moving one row of pins along the groove based on the GWG concept. Meanwhile, the sidelobe levels of the radiation patterns are reduced to -20 dB by controlling the height and distance of pins along groove. The beam direction of the low sidelobe leaky wave antenna changes from 110 degrees to 140 degrees, while the frequency shifts from 25 to 35 GHz. Another dimension of the beam scanning capability is realized with the Butler matrix in groove GWGs. The design of this Butler matrix is based on the coupling between multilayered groove GWGs. By this means, the low sidelobe leaky wave antennas are connected directly to the Butler matrix with no more transition structures. The main beam direction of the antenna array shifts from -41 degrees to 41 degrees, when the exciting ports change in order. The simulated and measured port isolations are lower than -15 dB over the frequency band of 27-35 GHz, and they match well with each other.