Double‐opening circularly polarized patch antenna with one desired opening diameter

Abstract

corresponds to a bandwidth of more than 51%. At the same time, the tuning range of the upper band for the same conditions is 1.14 $ 1.365 GHz, which corresponds to an 18% bandwidth. As the response of a capacitor is asymmetric with respect to the centre frequency, a relatively smaller tuning range is obtained in the upper band. In this tuning range, the ratio between the upper and the lower resonant frequencies is 1.65 $ 2.37. The phase balance between S 21 and S 31 remained between 85.5 and 104.4 in the lower band and between À97.5 and À90.2 in the upper band. Measured S-parameters for three different bias conditions are shown in Figure 4. CONCLUSIONA frequency-tunable dual-band branch line coupler based on CRLH transmission lines is presented. All inductors and shunt connections are eliminated completely through a conversion, resulting in a CRLH transmission line that is suitable for frequency tuning. Based on such CRLH lines, a frequency-tunable dual-band branch line coupler is designed with centre frequencies at 0.6 and 1.2 GHz. A method to maintain a constant upper and lower frequency ratio remains as future work.ABSTRACT: A single-feed circularly polarized patch antenna has been designed with two openings. Their respective influences are investigated. Circular polarization can be achieved by precisely dimensioning them. By combining openings with respective cumulative or attenuating effects, the diameter of one chosen opening can be designed to fit a required diameter.