Design of Dual-Band Omnidirectional Cylindrical Dielectric Resonator Antenna

Design of a dual-band omnidirectional cylindrical dielectric resonator antenna (DRA) using TM
₀₁₁
and TM
₀₁₂
modes is investigated in this letter. The limit of frequency ratio is found, and formulas that determine the dimensions of the DRA from two given frequencies have been provided. To verify the theory, a dual-band omnidirectional cylindrical DRA operating in 3.5-GHz WiMAX and 5.8-GHz WLAN bands is designed and tested. The reflection coefficient, radiation pattern, and antenna gain are studied, and reasonable agreement between measurement and theory is observed.