Microstrip Coupled Line Composite Right/Left-Handed Unit Cell

This letter presents a new composite right/left-handed (CRLH) unit cell, which takes advantage of the microstrip coupled line even and odd modes. The new cell does not require vias, it is patterned on a single metal layer, and it has a geometrical circuit model that simplifies the design flow. A novel CRLH transmission line is also proposed. It does not have a cutoff frequency, the operating bandwidth extends from dc to 4 GHz, and it is balanced at the first and second transition frequencies between right- and left-handed bands. The theoretical expectations have been confirmed by EM simulations and measurements.