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This paper presents measurements using a dual-polarised radiometer operating at 93 GHz to detect ice or water on asphalt in laboratory conditions. The brightness temperatures of both H and V polarizations were measured for a dry surface, liquid water, and ice on asphalt at observation angles of 50° and 56°. The results presented in this paper demonstrate that the studied road conditions can be identified by the radiometer. The measurements are compared with a model and surface parameters, such as dielectric constant and roughness are fitted and compared to reference values. The experiments and results, described in this article, are the first steps towards the future installation of a polarimetric sensor on a moving vehicle for traffic safety. [ABSTRACT FROM AUTHOR]

Introduction: Current techniques for estimating catheter tip temperature in ablative therapy for cardiac arrhythmias rely on thermocouples or thermistors attached to or embedded in the tip electrode. These methods may reflect the electrode temperature rather than the tissue temperature during electrode cooling so that the highest temperature away from the ablation site may go undetected. A microwave radiometer is capable of detecting microwave radiation as a result of molecular motion. In this study, we evaluated microwave radiometric thermometry as a new technique to monitor temperature away from the electrode tip during ablative therapy utilizing a saline model. Methods and Results: A microwave radiometer antenna and fluoroptic thermometer were inserted in a test tube with circulating room temperature saline kept constant at 23.5°C while the surrounding saline bath was heated from 37°C to 70°C. For every degree rise in the warm saline bath placed either 5mm or 8mm from the radiometer antenna, the radiometer temperature changed 0.26°C and 0.14°C respectively while the fluoroptic temperature probe remained constant at 23.5°C. The radiometer temperature was highly correlated with the warm saline bath temperature (R2=0.997 for warm saline 5mm from the antenna, R2=0.991 for warm saline 8mm from the antenna). Conclusions: Microwave radiometry can estimate distant temperatures by detecting microwave electromagnetic radiation. The sensitivity of the microwave radiometer is also distance-dependent. The microwave radiometer thus serves as a promising instrument for monitoring temperatures at depth away from the catheter-electrode tip in ablative therapy for cardiac arrhythmias. [ABSTRACT FROM AUTHOR]

Microwave sensors with their unique capabilities offer certain specific advantages for applications like geological survey for petroleum and mineral prospecting, crop and vegetation monitoring, soil moisture detection, water resources management etc. They are also capable of measuring ocean surface wind speed and direction, wave heights, wave spectra etc and to map the ocean wave structure. This paper presents the basic physics and description of microwave remote sensing, both passive and active, sensors and reviews the present status and future possibilities in sensor technology and applications. [ABSTRACT FROM AUTHOR]