In the terahertz band,the dispersive characteristic of dielectric material is one of the major problems in the scaled radar cross section(RCS)measurement,which is inconsistent with the electrodynamics similitude deduc...In the terahertz band,the dispersive characteristic of dielectric material is one of the major problems in the scaled radar cross section(RCS)measurement,which is inconsistent with the electrodynamics similitude deducted according to the Maxwell’s equations.Based on the high-frequency estimation method of physical optics(PO),a scaled RCS measurement method for lossy objects is proposed through dynamically matching the reflection coefficients according to the distribution of the object facets.Simulations of the model of SLICY are conducted,and the inversed RCS of the lossy prototype is obtained using the proposed method.Comparing the inversed RCS with the calculated results,the validity of the proposed method is demonstrated.The proposed method provides an effective solution to the scaled RCS measurement for lossy objects in the THz band.展开更多
The publisher regrets that some misprints appeared in the formula for the correction factork on page 343.It is reprinted correctly as the following:k=n(1-e<sup>-λ(t<sub>1</sub>-t<sub>0</su...The publisher regrets that some misprints appeared in the formula for the correction factork on page 343.It is reprinted correctly as the following:k=n(1-e<sup>-λ(t<sub>1</sub>-t<sub>0</sub>)/n</sup>)/e<sup>λ(t<sub>1</sub>-t<sub>0</sub>)</sup>-1·(sum from i=1 to n N<sub>ai</sub>e<sup>iλ(l<sub>1</sub>-l<sub>0</sub>)/n</sup>)/sum from i=1 to n N<sub>ai</sub>展开更多
Radar cross section (RCS) of non-sphericai raindrops is calculated by using the software CST based on finite integral method and compared with RCS of spherical raindrops. The revised factor of non-spherical raindrop...Radar cross section (RCS) of non-sphericai raindrops is calculated by using the software CST based on finite integral method and compared with RCS of spherical raindrops. The revised factor of non-spherical raindrops is obtained. The radar reflectivity with precipitation change of four distribution models of M-P, Gamma, JD and JT combining the revised factor is gotten using trapezoidal integration. When the infuence of non-spherical raindrops is considered, the accuracy of precipitation measurement of four distribution models can be separately improved 8.77%, 8.47%, 10.53% and 8.04% in the case of rain intensity is 100 mm/h.展开更多
This paper presents the scheme,function and technical specifications of170-325GHz waveband radar cross sec-tion(RCS) measurement system.Some steps are taken to improve the performance of the system,including multileve...This paper presents the scheme,function and technical specifications of170-325GHz waveband radar cross sec-tion(RCS) measurement system.Some steps are taken to improve the performance of the system,including multilevel ampl-i fication and frequency multiplication,low-order harmonic mixing,using external signal generators and intermediary fre-quency(IF) receiver.Considerable dynamic range and other characteristics are obtained with these approaches.Finally,the concrete implementation and experiment of1mm RCS measurement system are described,and feasibility of the system stud-ied in this paper is verified.展开更多
基金Supported by the National Natural Science Foundation of China (Nos. 11105081, 11275110 and 11375103) and the National Energy Application Project For Research and Demonstration (No. 20131660315).
基金supported by the National Natural Science Foundation of China(Grant Nos.61871386,61971427,62035014,and 61921001)the Natural Science Fund for Distinguished Young Scholars of Hunan Province,China(Grant No.2019JJ20022)。
文摘In the terahertz band,the dispersive characteristic of dielectric material is one of the major problems in the scaled radar cross section(RCS)measurement,which is inconsistent with the electrodynamics similitude deducted according to the Maxwell’s equations.Based on the high-frequency estimation method of physical optics(PO),a scaled RCS measurement method for lossy objects is proposed through dynamically matching the reflection coefficients according to the distribution of the object facets.Simulations of the model of SLICY are conducted,and the inversed RCS of the lossy prototype is obtained using the proposed method.Comparing the inversed RCS with the calculated results,the validity of the proposed method is demonstrated.The proposed method provides an effective solution to the scaled RCS measurement for lossy objects in the THz band.
文摘The publisher regrets that some misprints appeared in the formula for the correction factork on page 343.It is reprinted correctly as the following:k=n(1-e<sup>-λ(t<sub>1</sub>-t<sub>0</sub>)/n</sup>)/e<sup>λ(t<sub>1</sub>-t<sub>0</sub>)</sup>-1·(sum from i=1 to n N<sub>ai</sub>e<sup>iλ(l<sub>1</sub>-l<sub>0</sub>)/n</sup>)/sum from i=1 to n N<sub>ai</sub>
基金Project supported by the Shanghai Leading Academic Discipline Project (Grant No.S30108)the National Natural Science Foundation of China (Grant No.61071185)+1 种基金the Key Technology Research and Development Program of Science and Technology Commission of Shanghai Municipality (Grant No.10511501702)the Science and Technology Commission of Shanghai Municipality (Grant Nos.08590700500, 08DZ2231100)
文摘Radar cross section (RCS) of non-sphericai raindrops is calculated by using the software CST based on finite integral method and compared with RCS of spherical raindrops. The revised factor of non-spherical raindrops is obtained. The radar reflectivity with precipitation change of four distribution models of M-P, Gamma, JD and JT combining the revised factor is gotten using trapezoidal integration. When the infuence of non-spherical raindrops is considered, the accuracy of precipitation measurement of four distribution models can be separately improved 8.77%, 8.47%, 10.53% and 8.04% in the case of rain intensity is 100 mm/h.
文摘This paper presents the scheme,function and technical specifications of170-325GHz waveband radar cross sec-tion(RCS) measurement system.Some steps are taken to improve the performance of the system,including multilevel ampl-i fication and frequency multiplication,low-order harmonic mixing,using external signal generators and intermediary fre-quency(IF) receiver.Considerable dynamic range and other characteristics are obtained with these approaches.Finally,the concrete implementation and experiment of1mm RCS measurement system are described,and feasibility of the system stud-ied in this paper is verified.