An X-Band Circularly Polarized Reflectarray Using Split Square Ring
An X-Band Circularly Polarized Reflectarray Using Split Square Ring Elements and the Modified Element Rotation Technique Ang Yu1, Fan Yang1, Atef Z. Elsherbeni1, and John Huang2 1. Center of Applied Electromagnetic Systems Research (CAESR) Electrical Engineering Dept., The University of Mississippi, University, MS 38677 2. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 [email protected], [email protected], [email protected], [email protected]
Introduction A reflectarray can be considered as the planar version of a conventional reflector antenna. It is realized by the discretization of a curved reflector surface with a certain number of reflecting elements, which are placed on a planar surface, each providing a proper phase delay to the reflected wave in order to achieve a planar phase front in a specified direction [1]. The reflectarray is proposed to have a lower profile compared with the conventional reflector, as well as to eliminate the power division transmission lines used for conventional arrays. The microstrip technology is usually applied in the fabrication of the reflectarray elements due to its well known advantages [2-5]. Three schemes have been proposed to obtain suitable phase delays for the elements at different positions, namely, the application of time or phase delay lines [2-3], the element size variation technique [4], and the element rotation (ER) method [5]. In this paper, an X-band circularly polarized reflectarray with split square ring elements is designed, fabricated and measured. To be compatible with a single layer tri-band reflectarray design [6], a modified element rotation technique is demonstrated. Operating at 8.4 GHz, the reflectarray prototype has a gain of 30.4 dB and an aperture efficiency of 53.7%. The axial ratio bandwidth (AR
Introduction A reflectarray can be considered as the planar version of a conventional reflector antenna. It is realized by the discretization of a curved reflector surface with a certain number of reflecting elements, which are placed on a planar surface, each providing a proper phase delay to the reflected wave in order to achieve a planar phase front in a specified direction [1]. The reflectarray is proposed to have a lower profile compared with the conventional reflector, as well as to eliminate the power division transmission lines used for conventional arrays. The microstrip technology is usually applied in the fabrication of the reflectarray elements due to its well known advantages [2-5]. Three schemes have been proposed to obtain suitable phase delays for the elements at different positions, namely, the application of time or phase delay lines [2-3], the element size variation technique [4], and the element rotation (ER) method [5]. In this paper, an X-band circularly polarized reflectarray with split square ring elements is designed, fabricated and measured. To be compatible with a single layer tri-band reflectarray design [6], a modified element rotation technique is demonstrated. Operating at 8.4 GHz, the reflectarray prototype has a gain of 30.4 dB and an aperture efficiency of 53.7%. The axial ratio bandwidth (AR
