Millimeter-Wave End-Fire Magneto-Electric Dipole Antenna and Arrays with Asymmetrical Substrate Integrated Coaxial Line Feed

A wideband vertically-polarized end-fire magneto-electric (ME) dipole antenna fed by an asymmetrical substrate integrated coaxial line (ASICL) is proposed for millimeter-wave (mm-wave) applications. The proposed ME dipole antenna has an impedance bandwidth of 60% and produces an end-fire radiation with a stable gain between 5.8 and 6.9 dBi in simulation. To verify the design concept and its application in arrays, a 1 × 8 linear array with a fixed beam and a 1 × 4 linear array with multiple beams are designed, fabricated and measured. The fabricated fixed-beam array prototype exhibits an impedance bandwidth of 62%, a peak gain of 15.9 dBi and a radiation efficiency of 79%. The multi-beam array is fed by a 4 × 4 ASICL Butler matrix. Experimentally, excellent beam-scanning radiation patterns with reasonably low side lobes and low cross polarizations are demonstrated at 24, 30 and 36 GHz. And an overlapped operating bandwidth of 28.6% is achieved by the fabricated prototype.