Dual composite right/left-handed (D-CRLH) leaky-wave antenna with low beam squinting and tunable group velocity

The propagation and radiation properties of dual composite right/left-handed (D-CRLH) transmission line metamaterials are presented, and validated experimentally with a 1D microstrip prototype. In its fast-wave regime, this structure operates as a leaky-wave antenna capable of backfire-to-endfire radiation scanning with beam squinting smaller than that of conventional CRLH (C-CRLH) antennas. It is shown that this DCRLH beam squinting can be further reduced by increasing the group velocity but that this can occur, close (and possibly beyond) to luminal velocities, only at the expense of losses produced by parasitic effects, a fundamental limitation which is demonstrated via the Bloch impedance concept.