Single-Layer Substrate-Integrated Broadside Leaky Long-Slot Array Antennas With Embedded Reflectors for 5G Systems

The single-layer substrate-integrated directive antennas designed for fifth-generation (5G) systems' application with broadside radiation in the Ka-band are presented. The antennas incorporate a couple of self-consistent embedded reflectors that are used to excite periodic radiating nonresonant long slots. Two concepts are used to provide a 180° phase shift between reflected waves from the reflectors to create the required broadside radiation from the slots within a certain band. For the first time, an open-circuit concept is used to form an integrated reflector, which is considered based on the equivalent magnetic walls of the cavity model of microstrip antennas. The presented designs showed a realized gain of 23 dBi at the design frequency. A good agreement between the prototype measurements and simulated results is observed.