A new protection method using an energy selective surface(ESS)is presented for protecting electronic equipments from attacking by high power electromagnetic weapons.ESS is an impedance surface that is sensitive to the...A new protection method using an energy selective surface(ESS)is presented for protecting electronic equipments from attacking by high power electromagnetic weapons.ESS is an impedance surface that is sensitive to the incident electromagnetic field intensity.The protection mechanism,structural design,equivalent circuit modeling,and full-wave simulations of ESS are discussed.Theoretical analysis and simulation results show that ESS is transparent to small signals but opaque to larger signals.The typical insertion loss of ESS is about 1.5 dB and the minimum shielding efficiency is about 20.0 dB in the L band.ESS with the variable transmission loss can be used for protecting electronic equipments from damage in intensive electromagnetic environments.展开更多
In order to study the thermoelectric efficiency of microwave heating and reproduction of asphalt pavements and the uniformity of reproduction temperature distribution, a waveguide excitation cavity is designed and app...In order to study the thermoelectric efficiency of microwave heating and reproduction of asphalt pavements and the uniformity of reproduction temperature distribution, a waveguide excitation cavity is designed and applied to the structural design of a microwave heater. The structural sizes of the incentive cavities are determined based on the waveguide transmission line theory. Using IE3D software, electromagnetic simulations are respectively carried out in four different situations, including the distances between the magnetron probes （antennas） and a short-circuit board, different horn electric lengths and aperture sizes, different dielectric properties of the asphalt mixture, and the distances between the asphalt surface and the mouth cavity. The results show that, when the distance between the magnetron probe and the short-circuit board is 32.5 ram, it is the best installation site; reduction of aerial length is the main factor in improving the heating uniformity. When the aggregate is limestone, the best heating effect can be produced. Maximum radiation efficiency can be realized by adjusting the space between the heater radiation port and the asphalt pavement. The experimental results of asphalt mixture heating in four different situations have a substantial agreement with the simulation results, which confirms that the developed microwave heater can achieve better impedance matching, thus improving the quality and efficiency of heating regeneration.展开更多
Due to electronic jamming transmitted by hostile electromc jamming equtpmcnts tional jamming from other illuminating sources in the complex electromagnetic environment, the per- formance of non-cooperative passive det...Due to electronic jamming transmitted by hostile electromc jamming equtpmcnts tional jamming from other illuminating sources in the complex electromagnetic environment, the per- formance of non-cooperative passive detection systems may degrade it significantly. To solve the problem, a receiving frame with multiple channels for signal preprocessing is designed and a theoret- ical analysis to the received signals in the complex electromagnetic environment is provided. Fur- thermore, a scheme for jamming removal using independent component analysis is proposed. Simula- tion results demonstrate the proposed scheme appears as a very appealing solution for removal of jam- ming and an approximate lOdB signal to distortion ratio over traditional schemes is obtained.展开更多
基金Project supported by National Basic Research Program of China(973 Program)National Eleventh-five Year Science and Technology Supporting Program of China(51333060302)
文摘A new protection method using an energy selective surface(ESS)is presented for protecting electronic equipments from attacking by high power electromagnetic weapons.ESS is an impedance surface that is sensitive to the incident electromagnetic field intensity.The protection mechanism,structural design,equivalent circuit modeling,and full-wave simulations of ESS are discussed.Theoretical analysis and simulation results show that ESS is transparent to small signals but opaque to larger signals.The typical insertion loss of ESS is about 1.5 dB and the minimum shielding efficiency is about 20.0 dB in the L band.ESS with the variable transmission loss can be used for protecting electronic equipments from damage in intensive electromagnetic environments.
基金The Sci-Tech Achievements Transformation Program of Colleges and Universities in Jiangsu Province(No.JH09-13)the Research Fund of Nanjing Institute of Technology(No.YKJ201005)
文摘In order to study the thermoelectric efficiency of microwave heating and reproduction of asphalt pavements and the uniformity of reproduction temperature distribution, a waveguide excitation cavity is designed and applied to the structural design of a microwave heater. The structural sizes of the incentive cavities are determined based on the waveguide transmission line theory. Using IE3D software, electromagnetic simulations are respectively carried out in four different situations, including the distances between the magnetron probes （antennas） and a short-circuit board, different horn electric lengths and aperture sizes, different dielectric properties of the asphalt mixture, and the distances between the asphalt surface and the mouth cavity. The results show that, when the distance between the magnetron probe and the short-circuit board is 32.5 ram, it is the best installation site; reduction of aerial length is the main factor in improving the heating uniformity. When the aggregate is limestone, the best heating effect can be produced. Maximum radiation efficiency can be realized by adjusting the space between the heater radiation port and the asphalt pavement. The experimental results of asphalt mixture heating in four different situations have a substantial agreement with the simulation results, which confirms that the developed microwave heater can achieve better impedance matching, thus improving the quality and efficiency of heating regeneration.
基金Supported by the National High Technology Research and Development Programme of China(No.2012AA7014061,2013AA7014061)
文摘Due to electronic jamming transmitted by hostile electromc jamming equtpmcnts tional jamming from other illuminating sources in the complex electromagnetic environment, the per- formance of non-cooperative passive detection systems may degrade it significantly. To solve the problem, a receiving frame with multiple channels for signal preprocessing is designed and a theoret- ical analysis to the received signals in the complex electromagnetic environment is provided. Fur- thermore, a scheme for jamming removal using independent component analysis is proposed. Simula- tion results demonstrate the proposed scheme appears as a very appealing solution for removal of jam- ming and an approximate lOdB signal to distortion ratio over traditional schemes is obtained.
