This paper presents a modified structure of the Vivaldi antenna based on an FR4 dielectric substrate of 0.8 mm thickness and 110 mm × 96 mm dimensions for ultra-wideband (UWB) detection systems. The modified Vivaldi antenna has two major novelties. (1) Bottle-shaped slots are etched on both sides of the classic Vivaldi antenna to extend the surface current path length and concentrate electromagnetic energy. ( 2) Rectangular metal strips are implemented in front of the exponential slot to guide the UWB radiation waveform in the desired direction. The modified Vivaldi antenna is evaluated using the CST 2020 software and measured using the vector network analyzer ranging from 3 to 8 GHz. The obtained results show that a maximum peak gain of nearly 9 dBi at 4 GHz can be achieved, the radiation efficiency is improved to 80%, the main lobe level is increased, and the side lobe level is decreased. To further demonstrate the performance of the proposed Vivaldi antenna, a UWB imaging experiment is designed. The imaging results show that the imaging system using the proposed antennas can obtain images with good resolution, which indicates that the antenna has good radiation characteristics and can be used for UWB detection applications.
With economic and social development, the psychological health problems of poor college students present new characteristics and new situation. Psychological causes become more complex and malignant events happen frequently. To solve the adverse psychological conditions is urgently needed in the college students' education work. Poor college students work, is to be about colleges and universities in the new period of cultivating qualified builders and reliable successors for the socialist basic task, according to a new problem, to explore the root causes, to find the effective method to solve the problem of poor college students' mental health, and improve the pertinence and effectiveness of poor college students' mental health work, to do a good job in people's satisfactory education, train and bring up all-round development of socialist builders and successors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.