分类: 地球科学 >> 空间物理学 提交时间: 2017-03-10
摘要: A novel single-layer reflectarray element for broadband use is proposed. Ansoft HFSS is used to analyze the reflection phase for the element. By varying the element size, a slow slope of the reflection phase curve with the phase range over 600° is achieved. A center-fed 121-element reflectarray antenna is designed using the proposed elements and a linearly polarized pyramidal horn antenna is used as the feed of the reflectarray. The simulated results show that the gain of 24.42dB at the center frequency of 13.58GHz with 3-dB gain bandwidth of 36.8% (from 11.08∼16.08GHz), demonstrating a wideband performance compared to the conventional designs.
分类: 地球科学 >> 空间物理学 提交时间: 2017-03-10
摘要: A single-layer broadband reflectarray antenna with four-arm spiral elements is presented. Large range reflection phase has been obtained by varying the length of the arms. The effects of different incident angles on the four-arm element are studied first. Then, a 441-element offset-fed linearly polarized reflectarray is fabricated and measured. The measured results agree well with the simulated results. Measured results show the gain level of 28.35 dB with 1-dB gain bandwidth of 28.7% (12.41-16.31 GHz) and aperture efficiency of 60.2% at center frequency of 13.58 GHz.
分类: 地球科学 >> 空间物理学 提交时间: 2017-03-10
摘要: A novel X-band single-layer unit cell structure with enhanced bandwidth for linearly polarized microstrip reflectarray antenna is proposed. The unit-cell structure is composed of two circular rings, each with a pair of gaps which are orthogonally placed, and two identical phase-delay lines attached to the outer circular ring. With this novel structure, a linear phase response ranging about 550° is achieved by varying the length of the phase delay line. An offset-fed reflectarray antenna composed of 277 elements forming an octagon-shape aperture is designed, fabricated, and measured to verify the broadband characteristic of the proposed unit cell. Measurement results show that 20% 1-dB gain bandwidth is realized. Besides, the maximum gain at 10 GHz is about 26.38 dBi, which means about 51.3 % efficiency is achieved. At the same time, the side lobe level and cross polarization for E-plane are also measured which are below −17.5 dB and −26 dB, respectively.