| Summary: | 碩士 === 國立臺灣大學 === 電信工程學研究所 === 106 === In this thesis, a Ka-band dual-circular polarization sequential antenna array design is proposed. The dual-circular polarization antenna element is a square microstrip patch antenna using dual probe-fed. In order to generate circular polarized wave, a compact 3 dB branch line coupler is used. Both microstrip lines with fractal design and open stub matched transmission line are applied to the propose dual-circular polarization sequential antenna array to minimize coupler size.
In generally, sequential design can be used to maintain wide-band axial ratio response. The 128 elements single polarized sequential array which has a return loss better than 10 dB in operation frequency band is realized. Besides, the antenna radiation patterns and wide axial ratio bandwidth are similar to simulation results.
To maintain good axial ratio, the proposed dual-circular polarization sequential antenna array employs two-layer sequential rotation technique. A 4×4 sequential array is proposed to demonstrate single layer feeding structure for dual-circular polarization without any crossover. The measurement results show that two-layer sequential rotation can achieve good axial ratio. Due to its compact size and planar construction, the proposed dual-circular polarization sequential antenna array is suitable for mobile satellite communication.
|
|---|
