Stacked Multi-Via Mushroom-Type EBG Structures With Glide Symmetry

In this work, the dispersion of stacked mushroom-type EBG structures exhibiting glide symmetry are investigated and compared with conventional single-via structures in the frequency range of 50–90 GHz, useful for millimetre-wave sensing. While standard single-via cells do not provide a stopband in this frequency range when stacked, a new glide-symmetric multi-via cell is shown to function as an EBG, independent of the number of layers. With the use of multi-mode transmission matrix method, the complex wavenumber for the unit cell is ob-tained. The calculation is performed by applying post-processing to the generalised S-parameters of the unit cell obtained by means of a commercial solver. The computation of the complex wavenumber is particularly advantageous, as its imaginary part facilitates the analysis of attenuation in the stopband. The stacked multi-via EBG structures with glide symmetry show promising results beneficial for the design of gap-waveguide components constructed with inexpensive multi-layer PCB technology.