Scannable Leaky-Wave Antenna Based on Ferrite-Blade Waveguide Operated Below the Cutoff Frequency

This article proposes a scannable leaky-wave antenna (LWA). The antenna consists of a ferrite-blade waveguide with a longitudinal slot on the upper wall, which has a tunable composite right-/left-handed (CRLH) property. 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 waveguide excited below its cutoff frequency. First, based on the modal analysis and calculated dispersion relation, the unbalanced CRLH response of the ferrite-blade waveguide is investigated. Second, an LWA is presented by using a longitudinal slot on the upper wall of the proposed ferrite-blade waveguide, where the tunable balance CRLH response is achieved and analyzed by the transverse resonance method (TRM). The proposed LWA can provide backward, broadside, and forward radiations by a change in the operation frequency or the magnetic bias, independently. The given results show a +59° to -57° sweep in the radiation beam when the magnetic bias of the ferrite changed from 1400 to 1600 Oe at the sampling frequency of 6.4 GHz. Moreover, the results show that the frequency tuning range is more than 600 MHz (6.2-6.8 GHz). The peak gain and efficiency of the proposed antenna are 7.1 dBi and 78.5% at 6.6 GHz, respectively.