End-Launch Horn Antenna Array for Ka-band 5G Applications

In a large scale antenna system for 5G beamforming, the antenna modules can be designed as end-launch components. This concept is demonstrated by adopting half-height-pin gap waveguide technology to design a 4-element linear array. A quasi-TEM horn antenna is realized by flaring the double ridge that is surrounded by the half-height-pin electromagnetic band gap (EBG) structure. The single antenna element shows an impedance bandwidth (-10 dB) of 35% at 30 GHz with the realized gain of 7 dBi. The same impedance bandwidth is maintained with a 4-element linear array having a gain of 13.6 dBi at 30 GHz. The quasi-TEM double ridge gap waveguide (RGW) antenna is excited through a planar microstrip transition. The microstrip-to-ridge transition is designed and optimized to achieve better impedance match. The overall antenna array performance in the operating frequency range, 27.5~38 GHz, is stable with radiation efficiency around 78 %.