Wideband mm-wave high-gain multibeam antenna array fed by 4 x 4 groove gap waveguide butler matrix with modified crossover

This paper presents a wideband millimeter wave (mm-Wave) high-gain multibeam antenna array fed by Butler Matrix (BM) based on groove gap waveguide (GGW) technology. First, the components of 4 x 4 GGW BM have been designed and analyzed, especially the proposed modified crossover, which greatly improves the performance of BM as feeding network. Then a 2 x 2-element subarray with three layers has been proposed, combined with the 4 x 4 GGW BM to form a 1 x 4 broadside antenna array. Finally, the prototype of high-gain wideband four-beam antenna array has been manufactured and measured. The measured results verify the superior performance of the multibeam antenna array between 26.3-29.7 GHz. The return loss (RL) can reach 15 dB and isolation between ports is also less than 15 dB, and the measured maximum gain of radiation patterns and the maximum radiation efficiency can also reach 19.05 dBi and 86.8%, respectively. The measured results have a good agreement with the simulated results.