分类: 地球科学 >> 空间物理学 提交时间: 2017-03-10
摘要: A novel X-band unit cell structure with improved bandwidth performance for single-layer microstrip reflectarray antenna is proposed. The new element structure consists of two circular rings, each with a pair of gaps, and two phase-delay lines are attached to the outer ring to provide the required phase shift. A 9� center-fed reflectarray antenna operating at 10 GHz is designed to validate the broadband performance of the proposed unit cell. Simulated results show 20% 1-dB gain bandwidth and 38.5% 3-dB gain bandwidth. The maximum gain at 10 GHz is 20.1 dB, which is equivalent to 40 % efficiency.
分类: 地球科学 >> 空间物理学 提交时间: 2017-03-10
摘要: In this paper, a novel X-band broadband single-layer unit cell with attached phase-delay lines for reflectarray antennas is proposed to surmount the limitation of the reflectarray bandwidth. The unit cell is composed of three circular rings, each with a pair of gaps which are mutually placed orthogonally, and two identical circular phase-delay lines are attached to the outer ring to provide the required reflection phase. After the simulation for the unit cell carried out, a large reflecting phase range of about 600�and almost linear phase curve are achieved at the center frequency of 10 GHz. Parallel phase curves of different frequencies ranging from 9 GHz to 12 GHz are also obtained. To validate the broadband performance of the proposed unit cell, a 9 �9 center-fed reflectarray antenna operating at X band is designed and simulated. Simulation results show that the designed antenna has 34% 1-dB gain bandwidth, which demonstrates that an obvious improvement on the bandwidth has been achieved compared to the previous works. Besides, the cross-polarization level is decreased to -40 dB by a mirror symmetric element arrangement.