Programmable leaky-wave antenna with periodic J-shaped metamaterial patches

The feasibility of digital tuning of a programmable metamaterial-based antenna is explored. A leaky-wave antenna is implemented by cascading metallic J-shaped units in a composite right-left handed formation to create tunable metamaterial properties in terms of the radiation direction. The gaps in the J-shaped units are programmed in either open or close to alter the radiation patterns. Owing to the electromagnetic homogeneity where the unit length is smaller than one-fifth of the wavelength, changing the gap states has an equivalent effect to gradually tune the dispersion diagram. Eight J-shaped patches are integrated in the leaky-wave antenna, and nine different gap states are designed. The dispersion diagram is found to vary the transition frequency from 9.4 to 8.7 GHz with steps of 0.1 GHz, thereby frequency-dependent scanning radiation patterns are realised. Moreover, thanks to the gradually varying dispersion diagram, a state-dependent which also means programmable scanning radiation patterns are acquired in the band from 9 to 9.3 GHz. Experiment results agree well with the finite-element-method numerical analysis.