Triple-Band Microstrip-Fed Monopole Antenna Loaded With CRLH Unit Cell

This letter presents a novel metamaterial-inspired planar monopole antenna. The proposed structure consists of a monopole loaded with a composite right/left-handed (CRLH) unit cell. It operates at two narrow bands, 0.925 and 1.227 GHz, and one wide band, 1.56-2.7 GHz, i.e., it covers several communication standards. The CRLH-loaded monopole occupies the same Chu's sphere as a conventional monopole that operates at 2.4 GHz. The radiation patterns at the different operating frequencies are still quasi-omnidirectional. Measurements and EM simulations are in a good agreement with the theoretical predictions.