Composite Right/Left-Handed Leaky-Wave Antenna With High Scanning Rate

The scanning rate of a composite right/left-handed (CRLH) leaky-wave antenna (LWA) is usually determined by the dispersive behavior of the corresponding CRLH unit cell. In this letter, a novel CRLH unit cell with high dispersive behavior is proposed and investigated. The unit cell is formed by four stubs embedded in a rectangular ring patch, which is grounded with several metal vias. The right-handed characteristic is enhanced by the ring patch, while the left-handed characteristic is reduced by the vias and the gaps between the patch and the stubs. Then, the unit cell is applied to design an LWA with high scanning rate. The measured result shows that the seamless scanning angle of the antenna prototype is 130° (−65° to +65°) within a frequency range from 9.3 to 9.93 GHz (i.e., 6.6% for fractional bandwidth). Therefore, the proposed LWA antenna is with a high scanning rate up to 19.7°/%BW.