Array of stacked leaky-wave antennas in groove gap waveguide technology

The design of an array of stacked leaky-wave antennas in groove gap waveguide technology is presented in this work. The proposed array is formed by simply stacking a number of leaky-wave antennas one on top of the other and feeding all of them with uniform amplitude and phase. The inter-element distance is studied in order to avoid grating lobes and to maximize the directivity. A feeding network based on vertical coupling is designed, where the input port feeds the bottom element, and then the energy is equally coupled to the other elements. To obtain maximum directivity the phase is corrected at each element separately. The central frequency of the proposed design is 28 GHz. With this technique of stacking the elements a pencil beam is achieved, i.e. the radiated energy is focalized in the two main planes. The designed array with four elements achieves an enhancement of + 5 dB, reaching 24.5 dBi of directivity in comparison to 19.6 dBi of directivity of the single leaky-wave antenna made in this technology. A prototype is manufactured and measured and its results are presented and compared with the simulations.