Unbalanced CRLH behavior of ferrite-loaded waveguide operated below cutoff frequency
Morteza Mohammadi Shirkolaei, Javad Ghalibafan
Abstract
This paper proposes a new unbalance composite right/left handed (CRLH) transmission line that consists of a normally magnetized ferrite-loaded rectangular waveguide. The left-handed (LH) behavior of this structure is based on the negative effective permeability of the ferrite material and the negative effective permittivity of the hollow metallic waveguide at the frequencies below the cutoff. By increasing the frequency and passing through the cutoff frequency, this structure behaves as a right handed (RH) transmission line. As a main advantage of the proposed structure, the CRLH response of this transmission line can be tuned by changing the magnetic bias of the ferrite layer. This tunable CRLH transmission line can be used to design a tunable microwave filter or a tunable leaky wave antenna (LWA) with backfire-to-endfire scanning capability. Compare to previous CRLH metamaterial structures, the proposed structure has an easy design and a wide frequency range of tunability.