Fully planar slow-wave substrate integrated waveguide based on broadside-coupled complementary split ring resonators for mmWave and 5G components

Abstract

The authors propose a new metamaterial-inspired substrate integrated waveguide (SIW) that utilises broadside-coupled complementary split ring resonators (BC-CSRRs) instead of metalised via holes, to confine propagation within the guiding channel. Due to the resonant behaviour of the BC-CSRRs, blocking of in-plane propagation is achieved in a straightforward and efficient manner. The final waveguide is synthesised by employing two rows of CSRRs instead of each via row, resulting in a fully-planar, easy to fabricate, cost-effective solution. This new waveguide exhibits outstanding propagation characteristics, with losses close to those of the conventional SIW, providing a highly promising platform to implement low-cost planar components for millimetre-wave applications. To further confirm the potential of implementing CSRR-based SIW components, they provide designs of leaky-wave antennas in the X- and Ka-band, utilising this new concept.