Techniques for Designing High Gain and Two‐Dimensional Beam Scanning Antennas for 5G

This chapter presents a number of novel concepts for designing antenna arrays, which achieve high gain levels together with wide-angle scan capability. It begins with the Luneburg lens antenna, which supports beam scanning over a very wide angular range, in both the elevation and azimuthal planes. The scanning feed array design for the lens is discussed next and, following this, a novel hemispherical version of the Luneburg lens is introduced. The next topic covered is the gain enhancement of a slotted waveguide antenna array ( SWAA ), as well as for scanning the array in both the longitudinal and transverse planes, for which a number of options are presented. A key focus of this chapter has been the design of phase shifters that utilize techniques that circumvent the use of conventional phase shifters—ferrite-based for instance—that are both lossy and expensive. The phase shifters proposed herein are based on the use of either electronic switches or vias of liquid metal partially filling drilled holes. Both approaches facilitate modifying the electrical length of the U-shaped waveguides that are inserted between the adjacent radiating elements to provide the requisite phase taper. Finally, the chapter presents an alternate design of a phase shifter based around substrate integrated waveguide ( SIW ) technology, which can be reconfigured by using liquid metal. Phase shifting techniques at both coarse and fine discretization levels have been detailed, and measured as well as simulated results have been included to validate the presented designs. It is anticipated that a number of concepts for the design of wide-angle and gain-enhanced scanning arrays presented in this chapter will be implemented in the near future in 5G systems operating in the millimeter wave regime, where the design challenges abound at present, and where novel concepts are welcomed.