Chang-Su Huh

Optimization of Stirrer with Various Parameters in Reverberation Chamber

Reverberation chambers are widely used in electromag- netic compatibility test facilities because they provide a large working volume and are cheaper than other types of test facilities. In addition, they provide a statistically uniform fleld and generate a high maxi- mum electric fleld within a relatively large volume. The volume of the cavity, the structure of the stirrer, and high tested frequency must be used in the reverberation chamber appropriately. Changing a volume of cavity dimensions and test frequency can be di-cult in the rever- beration chamber because they were determined already in the design process. In these cases, the stirrer should be changed. We investigated of the efiects of various stirrer angles and heights on a reverberation chamber. The optimization of the stirrer with respect to various stirrer parameters was investigated; these parameters are related to fleld uni- formity, the quality factor, stirred e-ciency, and electric fleld polarity. Our results suggest that a reverberation chamber can be successfully operated if careful decisions are made regarding the stirrer design.

Degradation in silicone rubber used for outdoor insulator by UV radiation

We investigate the aging by UV radiation of silicone rubber used for outdoor insulators. Results from the measurement of surface potential decay by corona charging and of contact angle show a change of surface electrostatic properties and a slow decrease of contact angle under UV irradiation. For changes in the micro-morphological and chemical structure of the UV-treated silicone rubber, we utilize several analytical techniques such as SEM, ATR-FTIR, and XPS. From this study, it is shown that chemical reactions, such as scissoring of side chain Si-CH/sub 3/, cross-linking and branching, occur on the surface of silicone rubber during the UV irradiation. Also, we observe the results of the depletion of low molecular weight chains by cross-linking and oxidation reactions. From the results of inclined plane tracking resistance tests and the above experiments, we propose that surface charging has an effect on the tracking resistance of insulating materials.

A PCB Noise Analysis Regarding Emp Penetration Using an Electromagnetic Topology Method

The usability of the EMT (Electromagnetic Topology) method is discussed and verified in this paper. The EMT results are compared to the results from a 3D fullwave electromagnetic solver. The electromagnetic wave shows a very fast rise time in the EMP (Electromagnetic Pulse) signal; the SUT (System Under Test) is a simple PCB strip line model. The resistances of the loads attached to each side of the strip line were 1 MΩ and 50 Ω. We then obtained the noise voltages occurring in each load when being penetrated by an EMP. We also discuss the frequency sweeps used to obtain the resonant frequencies of the model. The results agree well with those from the CST Microwave Studio. The EMT method would be more accurate if the dielectric tangent loss and copper loss are considered.

A VALIDATION OF CONVENTIONAL PROTECTION DEVICES IN PROTECTING EMP THREATS

The performance of complementary ESD/Lightning pro- tection devices being exposed to EMP was studied. We studied pro- tection devices such as GDT (Gas Discharge Tube), TVS (Transient Voltage suppressor), and Varistor. The EMP signal has a very fast rise time of 100psec and the maximum peak voltage of 2kV. The GDT could not protect the EMP signal. The varistor showed about 35% of protection ability, and the TVS showed about 50% of protection abil- ity. Thus the GDT is not a proper device to protect EMP. However, all of the protection devices did not show their nonlinear property.

Surface Properties and Adhesion of Semiconducting and Insulating Silicone Rubber by Corona Discharge Treatment

In this work, the effects of the corona treatment on surface properties of semiconducting silicone rubber were investigated in terms of contact angles, ATR-FTIR(Attenuated total reflection fourier transform infrared spectroscopy) and XPS(X-ray photoelectron spectroscopy). And the adhesive characteristics were studied by measuring the T-peel strengths. Based on chemical analysis, the surface modification can be mainly ascribed to the creation of chemically active functional groups such as C-O, C

Damage Effect and Delay Time of CMOS Integrated Circuits Device with Coupling Caused by High Power Microwave

This paper examines the damage effect and delay time of CMOS integrated circuits device with coupling caused by high power microwaves. The waveguide and magnetron was employed to study the influence of high power micro-waves on CMOS inverters. The CMOS inverters were composed of a LED circuit for visual discernment. Also CMOS inverters broken by high power microwave is observed with supply current and delay time. When the power supply current was increased 2.14 times for normal current at 9.9 kV/m, the CMOS inverter was broken by latch-up. Three different types of damage were observed by microscopic analysis: component, onchipwire, and bondwire destruction. Based on the results, CMOS inverters can be applied to database to elucidate the effects of microwaves on electronic equipment.

Surface Analysis of Plasma-treated PDMS by XPS and Surface Voltage Decay

Surface states of polydimethylsiloxane (PDMS) treated by plasma were investigated by the analysis by x-ray photoelectron spectroscopy (XPS) and surface voltage decay. Plasma treatment causes the silica-like(SiOx/, x

The Characteristics of the Output Voltage Ferroelectrics for High Voltages Pulse Generators

Abstract - High power pulse generating technology is to accumulate the energy for relatively long and then to create a strong force by emitting the energy very fast. High power pulse generating technology has recently been using in various fields like environments, industry, research, military and so on. Numerous studies about high power pulse generators have already been performed and commercialized in various conditions. However, in aspect of their size and weight, it is hard to carry the generators which currently have been developed. For these reasons, din nations like America or Russia, the researches have been performed for Ferroelectric Generators(FEG), which have relatively simple structure and are economical. To realize the ferroelectric generator, in this study, we selected the PZTs which have different physical properties respectively, and then shocked them using explosives. The PZT samples with volumes of 0.31 ~ 0.94㎤ were depolarized by shocked and produced the waveform that have peak voltages of 4.28 ~ 15kV. The lowest relative permittivity sample generated much higher peak voltage. And sudden voltage drops which seem to be caused by dielectric breakdown were observed in some experiments using low youngs modulus samples. Also, increase in thickness led to increase in peak voltage, but the ratio of the voltage rise did not reach the ration of the thickness increase.Key Words : Ferroelectrics, Pulse Generators, PZT* General Motors Korea** Dept. of Electrical Engineering, INHA University***Hanwha Corporation† Corresponding Author : Dept. of Electrical Engineering INHA University, KoreaE-mail : cshuh@inha.ac.krReceived : December 30, 2011; Accepted : August 27, 2013

The Susceptibility of Electronic Circuits inside the Cavity by HPEM(High Power Electromagnetics) Environment

Modern electronic circuits are of importance for the function of communication, traffic systems and security systems. An intentional threat to these systems could be of big casualties and economic disasters. This study has examined susceptibility of electronic circuits inside the cavity by HPEM(High Power Electromagnetics). The UWB measurements were done at an anechoic chamber using a RADAN voltage source, which can generate a transient impulse of about 200 kV. The HPEM wave penetrated inside the metal case appeared to the long damped ringwave of pulse length compared with the incident wave. In addition, the resonant frequency generated inside the metal case occurred primarily in the range of 1~3 GHz. The frequency band of 1~3 GHz was influenced on the electronic circuit, which was confirmed by an external antenna and an internal absorber. The electronic circuit was influenced by HPEM infiltrated into the cavity at the 86 kV/m out of the metal cases. Also in case of an absorber the susceptibility of an electronic circuit was smallest among other cases(aperture, antenna). It is considered that absorber has a function absorbing electromagnetic wave infiltrated into the cavity and simultaneously limiting resonance by varying a boundary condition inside the cavity. Based on the results, electronic equipment systems could be applied to protection that has suited system requirements.

Improvement of Interfacial Performances on Insulating and Semi-conducting Silicone Polymer Joint by Plasma-treatment

In this paper, we investigated the effects of short-term oxygen plasma treatment of semiconducting silicone layer to improve interfacial performances in joints prepared with a insulating silicone materials. Surface characterizations were assessed using contact angle measurement and x-ray photoelectron spectroscopy (XPS), and then adhesion level and electrical performance were evaluated through T-peel tests and electrical breakdown voltage tests of treated semi-conductive and insulating joints. Plasma exposure mainly increased the polar component of surface energy from to with increasing plasma treatment time and then leveled off. Based on XPS analysis, the surface modification can be mainly ascribed to the creation of chemically active functional groups such as C-O, C