Voltage pulses with fast rise time can be obtained from Marx circuits based on avalanche transistors. In this research, the ZETEX avalanche transistors are used as the switches in a Marx circuit to generate stable vol...Voltage pulses with fast rise time can be obtained from Marx circuits based on avalanche transistors. In this research, the ZETEX avalanche transistors are used as the switches in a Marx circuit to generate stable voltage pulses with double-exponential waveform and fast rise time. By using these transistors, the circuit is able to generate higher pulsed voltage with fewer stages. A three stages and a ten stages Marx circuit, as well as their triggering circuits, are designed. The two Marx circuits are also tested by simulations based on the Pspice code and by experiments, results of which are consistent with each other. With the ten stages Marx circuit, we obtain positive and negative pulses with the rise time of about 1.5 ns, the amplitude above 1 100 V, and the pulse width below 5 ns. It is proved that the proposed Marx circuit equipped with avalanche transistors could be an effective kind of solid-state pulse generator.展开更多
To achieve the electric field strength and the induced currents in equivalence in susceptibility tests with the high-level field radiation above 400 MHz,a double differential-mode(DM) current injection method based on...To achieve the electric field strength and the induced currents in equivalence in susceptibility tests with the high-level field radiation above 400 MHz,a double differential-mode(DM) current injection method based on directional couplers is proposed.Two cascaded symmetrical directional couplers compose a coupling device to inject the DM currents.When the coupling device is used,two devices are necessary to achieve the equivalence between radiation and injection,i.e.the equivalence between the injected voltages and the field strength,which is linear,regardless of the characteristics of the equipment under test(EUT).The results are verified by experiments using typical coaxial cables and nonlinear devices,where the equivalence between the nonlinear EUT responses induced by radiation and injection at both ends is achieved by using two coupling devices.At a frequency up to 1.75 GHz,the maximal experimental error is only 3.39%.The experimental results confirm the accuracy of the proposed method even both the EUTs work in the nonlinear region.The proposed method is applicable for radiated susceptibility(RS) testing of interconnected systems in the microwave frequency band.展开更多
A monopole and a dual-polar ten-stage miniature Marx generators with avalanche transistors are designed and developed for experiments of electromagnetic pulses.These avalanche transistors,which exceed traditional gas-...A monopole and a dual-polar ten-stage miniature Marx generators with avalanche transistors are designed and developed for experiments of electromagnetic pulses.These avalanche transistors,which exceed traditional gas-gap switches in stability,size and repetition rate,are used as the high-speed switches in the Marx circuit.The influences of charging resistors,capacitances and load impedances on pulse width,repetition rate of output pulses are analyzed.The monopole Marx circuit has a size of 74 mm×32 mm,and its output voltage is1.8 kV when the charging voltage is 280 V.The dual-polar Marx circuit,which is 98 mm×32 mm,can generate either positive or negative polarity pulses synchronously with an output voltage of±1.6 kV,and a repetition rate of 10 kHz.The feasibility of the presented dual-polar Marx generator is proved by further tests.展开更多
For studying the coupling effect of electromagnetic irradiation to rectangular enclosure with wire penetration,a new hybrid model is proposed to determine the shielding effectiveness of the enclosure.This model based ...For studying the coupling effect of electromagnetic irradiation to rectangular enclosure with wire penetration,a new hybrid model is proposed to determine the shielding effectiveness of the enclosure.This model based on rectangular-enclosure equivalent circuit regards the penetrating wire as a monopole antenna,and the frequency-domain results of calculation using this model match with that of computer simulation technology(CST)Microwave Studio.Meanwhile,this new model requires far less computation than traditional methods:3 s for one sample on an average personal computer.Based on the presented model,the relationships between enclosure volume,external length of wire penetration,internal length of wire penetration,and shielding effectiveness are analyzed.In the frequency range from 100 MHz to1 000 MHz,when keeping the length of penetrating wire unchanged,the shielding effectiveness of an enclosure at its center point increases with the cavity volume.There is no obvious effect from the external length of penetrating wire on the shielding effectiveness.If the external length of a penetrating wire is 8 cm unchanged,the shielding effectiveness of the penetrated enclosure at its center point declines with the increase of internal length of the penetrating wire.展开更多
基金Project supported by National Science Key Laboratory Foundation of China(9140C870103120C87028)
文摘Voltage pulses with fast rise time can be obtained from Marx circuits based on avalanche transistors. In this research, the ZETEX avalanche transistors are used as the switches in a Marx circuit to generate stable voltage pulses with double-exponential waveform and fast rise time. By using these transistors, the circuit is able to generate higher pulsed voltage with fewer stages. A three stages and a ten stages Marx circuit, as well as their triggering circuits, are designed. The two Marx circuits are also tested by simulations based on the Pspice code and by experiments, results of which are consistent with each other. With the ten stages Marx circuit, we obtain positive and negative pulses with the rise time of about 1.5 ns, the amplitude above 1 100 V, and the pulse width below 5 ns. It is proved that the proposed Marx circuit equipped with avalanche transistors could be an effective kind of solid-state pulse generator.
基金supported by National Basic Research Program of China(973 Program)
文摘To achieve the electric field strength and the induced currents in equivalence in susceptibility tests with the high-level field radiation above 400 MHz,a double differential-mode(DM) current injection method based on directional couplers is proposed.Two cascaded symmetrical directional couplers compose a coupling device to inject the DM currents.When the coupling device is used,two devices are necessary to achieve the equivalence between radiation and injection,i.e.the equivalence between the injected voltages and the field strength,which is linear,regardless of the characteristics of the equipment under test(EUT).The results are verified by experiments using typical coaxial cables and nonlinear devices,where the equivalence between the nonlinear EUT responses induced by radiation and injection at both ends is achieved by using two coupling devices.At a frequency up to 1.75 GHz,the maximal experimental error is only 3.39%.The experimental results confirm the accuracy of the proposed method even both the EUTs work in the nonlinear region.The proposed method is applicable for radiated susceptibility(RS) testing of interconnected systems in the microwave frequency band.
基金Project supported by China Postdoctoral Science Foundation （20100481488）, Key Fund Project of Advanced Research of the Weapon Equipment （9140A33040512JB3401）.
基金Project supported by National Natural Science Foundation of China （50977091 ）.
文摘A monopole and a dual-polar ten-stage miniature Marx generators with avalanche transistors are designed and developed for experiments of electromagnetic pulses.These avalanche transistors,which exceed traditional gas-gap switches in stability,size and repetition rate,are used as the high-speed switches in the Marx circuit.The influences of charging resistors,capacitances and load impedances on pulse width,repetition rate of output pulses are analyzed.The monopole Marx circuit has a size of 74 mm×32 mm,and its output voltage is1.8 kV when the charging voltage is 280 V.The dual-polar Marx circuit,which is 98 mm×32 mm,can generate either positive or negative polarity pulses synchronously with an output voltage of±1.6 kV,and a repetition rate of 10 kHz.The feasibility of the presented dual-polar Marx generator is proved by further tests.
基金Project supported by National Basic Research Program of China(973 Program)Arm Pre-Research Program(51333030101),National Natural Science Foundation of China(61372040)
文摘For studying the coupling effect of electromagnetic irradiation to rectangular enclosure with wire penetration,a new hybrid model is proposed to determine the shielding effectiveness of the enclosure.This model based on rectangular-enclosure equivalent circuit regards the penetrating wire as a monopole antenna,and the frequency-domain results of calculation using this model match with that of computer simulation technology(CST)Microwave Studio.Meanwhile,this new model requires far less computation than traditional methods:3 s for one sample on an average personal computer.Based on the presented model,the relationships between enclosure volume,external length of wire penetration,internal length of wire penetration,and shielding effectiveness are analyzed.In the frequency range from 100 MHz to1 000 MHz,when keeping the length of penetrating wire unchanged,the shielding effectiveness of an enclosure at its center point increases with the cavity volume.There is no obvious effect from the external length of penetrating wire on the shielding effectiveness.If the external length of a penetrating wire is 8 cm unchanged,the shielding effectiveness of the penetrated enclosure at its center point declines with the increase of internal length of the penetrating wire.
