This article concerns a structure of high-impedance wires (HIW) based on ferrite substrate coplanar waveguide (CPW). Slotted planar stubs are etched on one or two ground planes of the CPW line. Several prototype measurements have been performed showing excellent performance to implement narrow-band microwave isolators. These HIW components can work at low bias-field giving an easier implementation in microwave devices.

This study presents for the first time the feasibility of a coplanar isolator using YIG material for applications in the Ku, K and Ka bands. The proposed structure is an asymmetric coplanar waveguide with a transverse array of unopened slots etched on a ground plane. Such structures are characterized by several cutoff frequencies on the transmission parameters. With a low dc magnetic field of 72 kAm −1 applied along with the slots, significant nonreciprocal effects greater than 20, 19 and 29 dB are obtained at 13.95, 23.39 and 39.61 GHz, respectively. The proposed structure can be used as a multiband isolator for microwave applications. The low biasing field of this multiband isolator and its compactness (88 mm 2) are its main advantages, which makes this structure particularly suitable for integration. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.