Simple Matching Technique using Finite Metasurface to Control Surface Waves

This article presents a simple matching technique to control surface waves (SWs) by using a finite metasurface matching section. The approach is based on a sub-wavelength array of patches which are employed as a simple and effective approach to control and guide SWs on a grounded dielectric slab (GDS). In order to excite the fundamental TM
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SW mode, a horn-shape surface-wave launcher (SWL) in substrate integrated waveguide (SIW) technology was employed. The structure and the matching metasurface are modeled with an equivalent circuit. By using this matching section, the reflection and transmission coefficients are improved from −6 dB to −12 dB and from −9 dB to −3.5 dB at 23.7 GHz, respectively. In addition, thanks to the finite metasurface region, the generated TM
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SW presents a uniform phase front allowing for efficient feeding of other antenna or passive elements implemented on the GDS. Measurements of a demonstrator prototype are also in agreement with full-wave simulations. This technique for SW control can be used in other microwave and millimeter-wave devices, for example, to reduce unwanted leakage, to route guided-waves, and feed leaky-wave antennas as well as other SW driven structures.