A TM guide for surface wave power routing and application to planar quasi-optical dividing/combining arrays

Surface waves (SWs) on planar substrates are generally an adverse effect that can degrade the performance of millimetre-wave circuits and antennas. However, with appropriate boundary conditions, such SWs can be harnessed as an efficient means of power transport achieving bound propagation along a grounded dielectric slab. Specifically this work studies TM fields generated from a planar SW source and launched into a novel guide for directive power routing. Analysis of the excited modes is completed and power channelling concepts are extended to a compact quasi-optical power combiner circuit for microwave and millimetre-wave frequencies of operation. Measurements and simulations are in agreement and impedance bandwidths of 20% are observed. Presented guidance and power directing techniques are also applicable to other printed circuit designs, multi-layer configurations, directional couplers, waveguide bends and transitions, repeater systems, new antenna feeds, and other power dividing/combining and routing circuits.