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1. chinaXiv:201703.00303 [pdf]

Single-layer reflectarray antennas with improved bandwidth by attaching phase-delay lines

Han, Chunhui; Zhang, Yunhua; Yang, Qingshan
Subjects: Geosciences >> Space Physics

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.

submitted time 2017-03-10 Hits11949Downloads860 Comment 0

2. chinaXiv:201703.00296 [pdf]

Single-layer broadband linearly polarized reflectarray antenna by using phase-delay lines

Han, Chunhui; Zhang, Yunhua; Yang, Qingshan
Subjects: Geosciences >> Space Physics

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.

submitted time 2017-03-10 Hits4901Downloads832 Comment 0

3. chinaXiv:201605.00308 [pdf]

CRLH waveguide based ka-band beam-steering leaky-wave antenna for radar application

Yang, Qingshan; Zhao, Xiaowen; Zhang, Yunhua
Subjects: Geosciences >> Space Physics

A KB-band beam-steering leaky-wave antenna (LWA) based on composite right/left-handed (CRLH) rectangular waveguide is proposed and investigated in this paper. The CRLH waveguide is composed of a traditional rectangular waveguide with short-circuited double ridge corrugations periodically mounted on one broadtail. The CRLH structure is air-filled to avoid dielectric loss. A straight long slot is cut on the other broadtail of the rectangular waveguide acting as the radiation aperture to realize a LWA. A balanced condition has been optimized for the LWA to acquire a continuous beam-steering capability from backward to forward quadrants. This capability is verified and high-gain performance is realized by simulations. Compared with other planar CRLH LWAs, the LWA proposed in this paper has the advantages of high power capacity, low loss and consistent high gain, which is very suitable for applications in practical radar systems.

submitted time 2016-05-03 Hits835Downloads478 Comment 0

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