科研之友
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摘要
A square-aperture metallic waveguide antenna with bidirectional circularly polarized (Bi-CP) radiations of the same sense is proposed in this letter. Circular polarization was realized by two identical rectangular metal strips installed on one lateral side of the waveguide with a 45 degrees inclination angle. The two rectangular metal strips were vertically separated by a distance of a quarter guided wavelength and horizontally intersected with an angle of 90 degrees. They were excited with the same amplitude and phase by feeding the antenna in the middle of their diagonal line. A 90 degrees phase difference between the two rectangular metal strips was introduced by the spatial distance of a quarter guided wavelength, and thus circular polarizations of the same sense in the two opposite radiating directions were generated. A quarter-wavelength impedance transformer was designed to help with the antenna's matching characteristic. The measured impedance bandwidth for vertical bar S-11 vertical bar <= -10 dB was 710 MHz (1.92 similar to 2.63 GHz), and the measured 3-dB axial-ratio bandwidth was 200 MHz (2.34 similar to 2.54 GHz). The measured bidirectional 3-dB axial-ratio beamwidth at 2.44 GHz was 62 degrees, and the power variation was smaller than 3 dB within this angular range.
- 出版日期2013
- 单位清华大学
