Measurement of Surface Reflectivity at Millimetre Wavelengths.

摘要

An active millimetre wave (MMW) experimental facility for measuring surface reflectivity of defence-related materials has been designed and constructed. The work was part of a DSTO task on Passive Millimetre-Wave Countersurveillance. The objective of the task was to undertake research on techniques for reducing susceptibility of military targets to detection by surveillance systems operating in the MMW region. This facility contributed to the task by providing a means for measuring the reflectivity of target materials and modified target surfaces. Millimetre wave radiation exhibits relatively low-loss atmospheric propagation at 35 GHz and 94 GHz and gives useful transmission through fogs and obscurants. The advantages of MMW radiation compared with microwave radiation include broader bandwidths, higher spatial resolution, greater directionality and the ability to use smaller equipment. These recognized advantages, and the increasing sophistication of advanced MMW technology have lead to the increased use of MMW systems and sub-systems on the battlefield. A requirement to investigate the reflection properties of materials at MMW frequencies and possible countersurveillance techniques has therefore developed. The facility can be used to measure the bistatic, monostatic or specular reflection from flat samples at horizontal, vertical or cross polarizations. (aw)