.3 Mm Band Target Radiation Characteristics Analysis

The study of millimeter-wave radiant characteristics is the theoretical basis of target detection and identification . This thesis is focus on the target radiant characteristics on 3 mm-band.The thesis is started from Planck radiation theorem. The target radiation theory and characteristics have been introduced and the corresponding relation of power and temperature have been given .Passive millimeter detection system which is also named millimeter radiometer is required in the measurement of radiation characteristic. The operational principle, components and characteristics of the radiometer have been described and calibrated by using the method of two-point, increment method on the basis of receiver linearity measurement. Three kinds of models have been given, containing Terrain background, general planar target and solid target in which the brightness temperature model of air-vegetation-soil has been researched particularly. The passive detection and analysis on Terrain background, ground and stealth target have been conducted with 3mm Dicke radiometer. Radiation temperature curves of different terrain background have been made .The difference of typical metal target radiation temperature have been analyzed. Also, the difference of stealth and general target which were covered with absorbing material has been contrasted.This is the procession of resolving inverse temperature integral equation, the stable solution of which is obtained on the basis of gradient method by introducing smooth algorithm.At last, the contrast experiment of imaging on the tank model have been conducted by using the millimeter wave passive imaging system, obtaining pictures and doing contrast on the stealth effect.