High-Gain Fan-Beam Leaky-Wave Antenna Using Symmetrical Long-slots for 5G Millimeter-Wave Base Station Applications

One of the most popular leaky-wave antennas is long-slot antennas in a rectangular waveguide which has a simple design and easy fabrication. The main disadvantage of a long-slot leaky-wave antenna is a radiation null at the broadside direction. In this paper, coating a dielectric layer on top of the long-slot antenna is proposed, and the radiation null is changed to a radiation peak with 27 dB improvement, which can be useful as an antenna for the fifth-generation (5G) communications in millimeter-wave. The proposed design is also applicable to base stations located in urban and suburban areas. The idea is also successfully implemented on a substrate integrated waveguide at 28 GHz. The designs are optimized to have a wide symmetrical radiation pattern, high gain, wide band-width, and wide beam-width in the horizontal plane. The realized gain of the coated long-slot waveguide antenna and the coated long-slot substrate integrated waveguide antenna are 20.2 dBi and 11.2 dBi, respectively.