Dispersion and Filtering Properties of Rectangular Waveguides Loaded With Holey Structures

Abstract

This paper analyzes thoroughly the dispersion and filtering features of periodic holey waveguides in the millimeterwave frequency range. Two structures are mainly studied depending on the glide and mirror symmetries of the holes. A parametric study of the dispersion characteristics of their unit cells is carried out. Glide-symmetric holey waveguides provide a higher propagation constant and a low dispersion over a wide frequency range regarding hollow waveguides. This property is particularly useful for the design of low-loss and low-dispersive phase shifters. We also demonstrate that glide-symmetric holey waveguides are less dispersive than waveguides loaded with glide-symmetric pins. Furthermore, we perform a Bloch analysis to compute the attenuation constants in holey waveguides with mirror and broken glide symmetries. Both configurations are demonstrated to be suitable for filter design. Finally, the simulation results are validated with two prototypes in gap-waveguide technology. The first one is a 180 o phase shifter based on a glide-symmetric holey configuration that achieves a flat phase shift response over a wide frequency range (27.5% frequency bandwidth). The second one is a filter based on a mirror-symmetric holey structure with 20-dB rejection from 63 GHz to 75 GHz.

On the Benefits of Glide Symmetries for Microwave Devices

“…One common solution for wide band higher-ordermode rejection is the waffle iron filter, which is based on periodic metallic pins [85]. Again here, glide-symmetric holes can possibly be used to replace the metallic pins and to produce filters [74], [86]. Fig.…”

Wideband Gap-Waveguide Phase Shifter Based on a Glide-Symmetric Ridge

“…In order to study the phase shift behavior produced by a unit cell, dispersion diagrams are very useful to assess this characteristic [16]. Figs.…”

“…Waveguide phase shifters loaded with pins [15] and holes [16] that preserve glide symmetry have demonstrated the benefits for producing phase shift in waveguides. This kind of higher symmetry greatly enhances the performance of radio-frequency devices [17].…”

A 12–20 GHz Wideband High-Power SP2T Switch Based on Gap Waveguide Technology

“…Figure 1 shows the geometry of the periodic pins and a groove gap waveguide (GGW) structure and dimensions, as well as the simulated dispersion diagram of the periodic pin structure. To realize the PMC surface, a periodic texture of metallic pins [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ] or holes [ 29 , 30 ] can be used, and by placing a metallic plate on its top, the bandgap is achieved. The periodic pin structures are more compact and have a broader bandwidth compared to the holey structures.…”