Broadband High-Gain Periodic Endfire Antenna by Using I-Shaped Resonator (ISR) Structures

A broadband high-gain periodic endfire antenna is presented in this letter. The gain enhancement is achieved by loading with an I-shaped resonator (ISR) structure in the endfire direction. Parameter extraction for the I-shape unit-cell structure is investigated to analyze its effect on the gain enhancement value of the antenna. Finally, both the ISR-loaded antenna and unloaded one are fabricated to verify the predictions. The measurements show that the ISR-loaded antenna presents gain of about 6.5-9.5 dB in the whole working band (about 5.1-8.3 GHz), which is about 1.5-3.5 dB more than the unloaded one. The advantages of broad bandwidth and high gain make this antenna valuable in wireless communication systems.