Liu Shanghe

A new function to represent the lightning return-stroke currents

We present a new function, the pulse function, to represent the lightning return-stroke currents. This function has the continuity of the first derivation at the time onset t = 0, is time-integrable, and can be conveniently used in the calculations of LEMP fields.

A new kind of lightning channel-base current function

In allusion to the disadvantages of double exponential function and Heidler function which are widely used to describe lightning channel-base current, a new kind of lightning channel-base current model is presented. The comparison among the three kinds of function shows that the new function is predominant over the other two. It is highly efficient in calculating lightning electromagnetic pulse fields (LEMP).

Measurement and analysis of Electromagnetic Fields Radiated by Corona Discharge

Corona discharge is a usual type of electrostatic discharge (ESD). Electromagnetic fields radiated by corona discharge could be harm to microelectronic devices of airplane and weapon systems. In this paper, corona discharge current is studied in theory and its characteristics are developed by the analysis of measurement data. Moreover, experiment simulation system of corona discharge is built for simulating corona discharge of spatial objects. Further, the characteristics of electromagnetic fields radiated by corona discharge are developed by time-frequency technology and wavelet analysis methods.

EMP energy transfer function on EED

The hazards of electromagnetic radiation to ordnance (HERO) program has extensively tested the detonating device, called electro-explosive device (EED), which heats up and initiates detonation via current flow. EED accidents can occur due to the action of an electromagnetic pulse (EMP). Any kind of system can be considered as an antenna to receive EMP energy and this energy may couple to the EED. The EED and its related problems are introduced and heat flow equations are studied. The amount and type of current induced in wires to an EED depends on the type of receiving antenna. Three basic types of antenna are discussed, loop antenna, dipole antenna and top-loaded antenna.

Experimental Study on the Damage Effects of Integrated Circuits Stressed with ESD EMP

Several RC (resistance and capacitance) combinations were adopted in ESS-AX200 ESD simulator to generate different ESD pulses. And the pulses were injected into an integrated circuit. The damage effects of the integrated circuit stressed with these pulses were investigated. Results showed that the current passing through the device will increase when the discharge voltage increases. The relationship between the peak energy absorbed by the IC chip and the discharge voltage can be modeled as the bell-shaped Gaussian function. The failure thresholds of the IC were the same order of magnitude and were found to vary by less than a factor of two

Theoretical and experimental study of the electromagnetic field generated by ESD

Publisher Summary This chapter presents a theoretical and experimental study of the electromagnetic field radiated by a thin wire with electrostatic discharge (ESD) current injected. With the development of modern electronic technology, electronic systems have become more and more integrated, mini-sized, and low power waste. While functions of the electronic systems are enhanced, they become more and more sensitive to electromagnetic interference and very low over-voltage and energy can cause them work abnormally. ESD is a familiar harmful electromagnetic source, and the transient radiation field generated by the initial heavy current pulse with fast-rise time and short-duration time during the discharge process can cause interference and damage to circuits. A numerical model of the field distribution is established using Finite-Difference Time-Domain (FDTD) method and characteristics of the radiation field are analyzed after calculating. The results show that the radiation field generated by the thin wire with ESD current injected is a kind of oscillation field and is far stronger than that generated by ESD spark at the same condition and the calculation results obtained by FDTD method are in agreement with the experimental results.

Numerical study of field radiated by a thin wire with ESD current injected

In this paper, the electromagnetic field radiated by a thin wire parallel to the ground with ESD current injected is studied using the FDTD method and a numerical computation model is established. Characteristics of the radiation field and its variation rules with the distance of the wire away from the ground are analyzed.

Study on the effects of relay switch of ESD simulator to ESD immunity test

In the paper the effects of the relay switch of an ESD simulator on ESD immunity test are discussed. Using a metal mesh enclosure, we improve the simulator. Experimental results show that the shielded simulator is more coincident with the real ESD event, and the test results are more credible.

Effects of propagation on the return stroke radiation fields

In this paper, we discuss the effects of the height of channel, the return stroke speed and the permittivity of ground on the return stroke radiation fields based on TL, MTLE, TCS and BG model. We assume a common current wave shape at the channel base and then calculate the electromagnetic field under different conditions. Some useful conclusions have been made in the paper.

Study on ESD characteristics and its effect mechanism

Based on experimental study on microcircuit and electric explosive device (EED) applied by electrostatic discharge (ESD), the characteristics and its electric conduction law of ESD are introduced. And it is shown that the generally accepted Ohms law is not followed at times under very high electrostatic field. In another words, ESD discharge curve is not an exponential decay one. ESD may form a hazard to microcircuit and EED. And its effect mechanism includes thermal effect of adiabatic process, electromagnetic interference from broadband electromagnetic radiation, overstress in high potential electrostatic field and field-caused breakdown effect etc. The failure rate may reach about 50% for unprotected MOS circuits and 10% for bipolar circuits due to general ESD hazards. The electrostatic ignition energy of EED is smaller with 2-3th power than that of the EED which is ignited through electrifying.