Standards Development For Remote Sensing at Microwave and Terahetz Frequencies
The Noise Project in the Electromagnetics Division of the National Institute of Standards and Technology (NIST) has proposed the development of standards for microwave brightness temperature for use in remote-sensing applications such as satellite-based weather observations. The standards would be based on existing fundamental standards for electromagnetic noise in waveguide systems. The connection to brightness temperature，which is a radiated quantity，would be made by means of a well characterized antenna. A heated calibration target would be used to supplement the basic standard，either as a check or to reduce the uncertainty by a redundant measurement.We have performed preliminary measurements at 26 GHz that demonstrate the feasibility of the proposed standard. A parallel effort is in progress for terahertz frequencies. For terahertz noise we are building a heated target to be used as a noise standard，since we did not already have fundamental noise standards for such high frequencies. This standard will be used with a terahertz radiometer. The radiometer is based on a receiver that uses a hot-electron bolometer (HEB) mixer that is coupled to the radiation by a quasi-optical adapter. We expect to perform terahertz noise measurements with the system by the end of the year.
microwave radiometer microwave remote microwave standards terahertz noise radiometer terahertz standards
James Randa Eyal Gerecht David K.Walker Amanda Cox Dazhen Gu Lixing You Robert L.Billinger
Electromagnetics Division National Institute of Standards and Technology (NIST) Boulder,Co 80305,U.S.A.
国内会议
北京
英文
33-42
2007-09-05（万方平台首次上网日期，不代表论文的发表时间）