Direct Spectrum Division Transmission for Highly Efficient Frequency Utilization in Satellite Communications

2012 ◽  
Vol E95-B (2) ◽  
pp. 563-571 ◽  
Author(s):  
Jun-ichi ABE ◽  
Fumihiro YAMASHITA ◽  
Katsuya NAKAHIRA ◽  
Kiyoshi KOBAYASHI
Keyword(s):  
Satellite Communications ◽  
Highly Efficient ◽  
Direct Spectrum

A Highly Efficient Dual-Band Transmitarray Antenna Using Cross and Square Rings Elements

2021 ◽  
Vol 36 (7) ◽  
pp. 852-857
Author(s):  
Yongliang Zhang ◽  
Xiuzhu Lv ◽  
Jiaxuan Han ◽  
Shuai Bao ◽  
Yao Cai ◽  
...  
Keyword(s):  
Satellite Communications ◽  
Dual Band ◽  
Band Ratio ◽  
Maximum Gain ◽  
Aperture Efficiency ◽  
Dielectric Substrates ◽  
Highly Efficient ◽  
X Band ◽  
Transmission Phase ◽  
Ku Band

In this paper, a highly efficient dual-band transmitarray antenna using cross and square rings elements is presented for X and Ku bands. The dual-band transmitarray is designed for downlink/uplink frequencies of Ku band satellite communications. The transmitarray element consists of four metal patches and two dielectric substrates. The metal patch is printed on both sides of the substrate. By optimizing the parameters, the transmitarray element can achieve a transmission phase coverage greater than 360° and work independently in both frequency bands. Then, a method to select the size of the element is proposed, so that all the elements in the array can realize the transmission phase of the two frequencies as much as possible. A 201-elements transmitarray antenna is fabricated and measured and the band ratio of the antenna is 1.13. The measured maximum gain at 11.5 GHz is 22.4 dB, corresponding to the aperture efficiency is 52.7%. The measured maximum gain at 13 GHz is 24.2 dB, corresponding to the aperture efficiency is 62.4%. The 1-dB gain bandwidths are 9.7% (10.8-11.9 GHz) at X band and 9% (12.6-13.8 GHz) at Ku band.

Highly efficient and selective photocatalytic CO2 to CO conversion in aqueous solution

2020 ◽  
Vol 56 (27) ◽  
pp. 3851-3854 ◽  
Author(s):  
Xiaomin Chai ◽  
Hai-Hua Huang ◽  
Huiping Liu ◽  
Zhuofeng Ke ◽  
Wen-Wen Yong ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Performance ◽  
Aqueous Media ◽  
Highly Efficient ◽  
Co Conversion

A Co-based complex displayed the highest photocatalytic performance for CO2 to CO conversion in aqueous media.

Tuning the pore structures and photocatalytic properties of a 2D covalent organic framework with multi-branched photoactive moieties

Nanoscale ◽  
2020 ◽  
Vol 12 (30) ◽  
pp. 16136-16142
Author(s):  
Xuan Wang ◽  
Ming-Jie Dong ◽  
Chuan-De Wu
Keyword(s):  
Photocatalytic Properties ◽  
Effective Strategy ◽  
Covalent Organic Framework ◽  
Highly Efficient ◽  
Pore Structures ◽  
Local Connection ◽  
Organic Framework

An effective strategy to incorporate accessible metalloporphyrin photoactive sites into 2D COFs by establishing a 3D local connection for highly efficient photocatalysis was developed.

Phased Arrays for Radio Astronomy, Remote Sensing, and Satellite Communications

2018 ◽  
Author(s):  
Karl F. Warnick ◽  
Rob Maaskant ◽  
Marianna V. Ivashina ◽  
David B. Davidson ◽  
Brian D. Jeffs
Keyword(s):  
Remote Sensing ◽  
Radio Astronomy ◽  
Phased Arrays ◽  
Satellite Communications
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