China
Africa
Explore chapters and articles related to this topic
Other Leak Detection Technologies
Published in Justin Starr, Water and Wastewater Pipeline Assessment Technologies, 2021
Microwaves are often classified by their band or range of frequencies. There are different standards for bands, often tied to national regulatory agencies, but the IEEE has developed a system of letter codes that are widely used in the industry today. S band frequencies range from 2 to 4 GHz, and include modern Wi-Fi, Bluetooth, and some forms of cellular communications. K band frequencies range from 18 to 26.5 GHz and are often used in automotive applications – adaptive cruise control radars and speed detection devices. Speeding drivers with older radar detectors may notice a high rate of false positives as newer vehicles with radar technology enter the roadways. X band frequencies at approximately 9 GHz can be used in spectroscopy or material identification applications.
Satellites
Published in Michael M. A. Mirabito, Barbara L. Morgenstern, Mitchell Kapor, The New Communications Technologies, 2004
Michael M. A. Mirabito, Barbara L. Morgenstern, Mitchell Kapor
Besides C-band spacecraft, a newer generation of satellite that employs a higher frequency range, the K-band, has become operational. The first class of this type of spacecraft uses the Ku-band (12/14GHz). This has an advantage. C-band satellite transmissions have been limited in power “to avoid interference with terrestrial microwave systems.”14 A Ku-band satellite is not similarly restricted, and the power of its downlink can be increased. This higher power also translates into smaller receiving dishes and points out a generalization between a satellite’s transmission and a dish’s size. As the power increases, the dish’s size can decrease.
Roles of carbon black or carbon fibre on improving mechanical and electromagnetic properties of ultra-high performance concrete in K-band frequency range
Published in Journal of Sustainable Cement-Based Materials, 2023
Yekai Yang, Shenchun Xu, Chengqing Wu
Moreover, it is often very important to construct buildings with strong electromagnetic radiation systems and equipment, such as those built in airports and power stations. Traditional cement-based composites cannot meet their performance requirements. On the other hand, ultra-high performance concrete (UHPC) is exploited in important building structures due to its high strength and good toughness [30–38]. Therefore, it is necessary to improve the electromagnetic wave absorption capability of UHPC by implementing appropriate additives. Our research team discussed the electromagnetic wave absorption capability of UHPC modified by CB and CF in the frequency range of 2-18GHz [39]. However, at present, many airport radars and other equipment employ high-frequency electromagnetic waves (such as K-band). The higher frequency of electromagnetic waves results in more serious harm to the human body. By this view, the electromagnetic wave absorption capacity of UHPC in the frequency range of 18–26.5 GHz should be tested and preferably improved to lessen electromagnetic pollution.
The broadband absorber based on plasma metastructure with spiral resonators
Published in Waves in Random and Complex Media, 2023
Haining Ye, Li Zeng, Baofei Wan, Haifeng Zhang
K-band refers to the frequency band of electromagnetic wave (EMW) 18∼27 GHz, which is a military band mainly used in radar communication and mobile satellite communication [25]. Currently, a growing body of countries focuses on the development and application of K-band broadband satellite communications, which is the grounds that the MSAs in this paper are designed in this frequency band.