| The design focus of the beam scanning folded reflect array antenna is to reduce the antenna’s scanning loss and profile,and to optimize the design of a common aperture surface phase distribution to achieve the effect of beam scanning.For beam scanning folded reflect array antennas,high gain and beam scanning can be achieved,but it is challenging and has application potential to achieve low-profile,low-loss wide-angle beam scanning within a wide bandwidth.The Ku band is above 10 GHz and is commonly used in the field of satellite broadcasting.Microwave,high frequency,very high frequency and broadcast television generally cannot interfere with it.In this paper,a common aperture optimization method is used to design and implement a wideband wide-angle coverage beam scanning folded reflect array antenna working in the Ku band through the aperture surface phase distribution.The main research content is divided into the following two aspects:(1)Firstly,a wide-angle beam scanning folded reflect array antenna based on a doublearrow polarization conversion reflective meta-surface unit is proposed and designed.In order to reduce the beam scanning loss,a common aperture multi-beam optimization method considering the incident wave irradiation weight factor and the captured power weight factor is proposed to obtain the phase distribution on the aperture surface through this optimization method.In order to reduce the profile of the antenna,a feed antenna based on SIW back cavity slot antenna is designed and integrated with the reflective surface on the same PCB board.In order to further reduce the profile of the antenna and obtain the best aperture efficiency design,this paper optimizes the optimal focal length position when the aperture efficiency is maximized by considering the influence of the irradiation power and overflow power of this feed.(2)Secondly,a wideband wide-angle coverage folded reflect array antenna is proposed and designed.In this paper,a high-efficiency dual-port ring wideband polarization conversion unit is designed as the meta-surface unit on the main reflector,and a wideband feed is designed by etching a U-shaped groove on the rectangular patch unit.In order to balance the scanning loss brought by different frequencies and improve the gain of the designed antenna,improvements have been made on the proposed multi-beam optimization method.Firstly,a method based on aperture field is used to replace the traditional ray tracing method to further determine the phase compensation required by each unit.Secondly,a flat gain within a wide bandwidth is obtained by introducing a frequency weight factor.A FRA antenna with 11 beam scanning working in the Ku band with a size of 264×264 mm was designed.The simulation experiment verified the effectiveness of the design method proposed in this paper.The results show that the designed common aperture FRA antenna achieves 3 d B beam coverage in the range of-28°～28° within the wide bandwidth range of 13.5GHz～16.5 GHz,with a maximum gain of 26.6 d Bi at the center frequency and an aperture efficiency range of 14%～20.9%,with flat gain and scanning loss less than 3 d B.Compared with the reported antennas with beam scanning capability,the designed folded reflect array antenna can achieve wider beam scanning within a wide bandwidth range,with lower scanning loss,higher aperture efficiency and lower profile. |
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