X-band active two-terminal leaky-wave antenna

Abstract

Figure 10 Width and temperature errors on profile retrieval in simulations by data fusion of 3, 35, 60, and 94 GHz radiometers with a bandwidth of 2 GHz. The length of the lossy line to be considered is 1 mm, and its lineic resistance is 100 Vrcm. In order to simplify our study, we assume losses to be only due to the dc resistance of the line; we then neglect phenomena such as skin effect. We create a steep hot spot of 200 mm with DT s 58C. In Figure 9, we can see the results of the inversion process applied to the radiometric data. We show that it is not possible to conclude about the true thermal gradient from one radiometer data. However, data fusion of the radiometric data at different frequencies in the adaptive filter allows a . very good estimation of the temperature « s 0.5% and of T the width of the hot spot. For the case of less severity on retrieval conditions, we give in Figure 10 the « and « errors as functions of the hot wT spot width. For example, a resolution of 100 mm for 58 Ci s retrieved with a width error about 20% and a temperature error less than 10%. 7. CONCLUSION The use of an inversion process based on a Kalman filtering in a nonclassical application brings a good retrieval of the shape and temperature of a thermal gradient. We obtain quantitative information about the temperature, with an a priori knowledge of the weighting functions involved in the radiometric measurement. We have shown, by means of a simulation, the possibility of simplifying a correlation radiometer by using small bandwidth systems. But another consequence concerns the im. provement of resolutions size and temperature if we use radiometers with very different bandwidths. It is then possible to define the pattern of a thermal microsensor. This type of system can be dedicated to the measurement of temperature inside a three-dimensional electronic circuit, where infrared measurement is not possible. The measurement of temperature in microelectronic components becomes possible if we work with several millimetric radiometers.