**6. Conclusions**

Printed ridge gap waveguide is an emerging technology with powerful capabilities that allow designing efficient beam switching networks for mm-Wave communications. In this chapter, various PRGW components designed for beam switching arrays at 30 GHz are presented. First, we present transitions to\from other guiding standards like coaxial and MSPL structures. These transitions provide efficient integration with these guiding standards. Then, hybrid couplers with rectangular and circular coupling sections are introduced. Crossover designs are also provided with various design techniques; either using multistage directional couplers or using compact single stage stepped design. A Schiffman phase shifter with 450 phase shift is also presented. Differential power dividers are introduced, one relying on slot coupling to two identical lines and the other depending on rat race design. The chapter also presents different designs of antennas covering all possible polarizations. It is then revealed how the usage of PRGW technology can provide efficient excitation of antennas with different polarizations and design profiles. Full beam switching networks are presented in the last section, where two different 4 4 butler matrices are introduced with their usage in achieving the beam scanning function of the array. Assessment of these various devices reveals the promising performance of the new PRGW structure over other competing technology candidates. The new PRGW technology can give better performance in terms of device size, bandwidth and fabrication costs.
