3D printed millimeter-wave magnetoelectric dipole antenna array fed by filtering butler matrix

In this paper, a millimeter-wave (mmWave) multi-beam magnetoelectric (ME) dipole antenna array employing filtering Butler matrix as beamforming network (BFN) is presented. The topology of the BFN is first proposed. As a component, the 180° filtering couplers are synthesized by coupling matrix theory to simultaneously achieve coupling and filtering characteristics. A 2 × 2 antenna array utilizing miniaturized ME dipoles is designed as the radiators combined with the BFN, making the radiation pattern realize 2D scanning performance. Using 3D printing technology, a prototype is fabricated. The reflection coefficients off four input ports are below −10 dB from 23.8 GHz to 26.8 GHz. The radiation pattern and gain are stable, and the efficiency remains above 80 %. This work innovatively integrates multi-beam characteristics with filtering characteristics in a single antenna array design. The filtering multi-beam antenna array has the potential to be applied in mmWave radar and communication systems.