A Method of Designing a Dual-Band Sector Ring Microstrip Antenna and Its Application

A dual-band sector ring microstrip antenna operating at the TM
₁₁
and TM
₀₂
modes is analyzed and then designed in this communication. Unlike previous analyses that use only cavity model or transmission line, a simpler analysis using both models is proposed. Accordingly, several closed equations are derived. Such equations determine the relationship among three important units of construction, namely the radii, the angle, and its operating frequencies, and with the operating factors in a dual-band sector ring patch. The errors between the proposed method and the cavity model are acceptable. The field and radiation patterns of the sector ring patch are also discussed. In addition, these analyses and equations are applied to design a dual-band sector ring microstrip antenna for WLAN. A novel coupling sector ring patch is then proposed to improve the performance of the antenna. The experimental results are in good agreement with the analyses and the simulations. The impedance bandwidths of the antenna are about 40 and 900 MHz with consistent broadside radiation patterns at 2.4 and 5.5 GHz band. Additionally, their measured average gains are about 5.1 and 6.3 dBi, respectively.