Yi Ru Jeong

Modeling of Leaked Digital Video Signal and Information Recovery Rate as a Function of SNR

Substantial information leakage at PC monitors and TV systems arises in the form of unintentional emissions of high-speed digital video signals, such as DVI/HDMI. The information recovery rate from the emanated video signal varies depending on the SNR of the receiver system, which is placed a certain distance away. In this study, a situation in which the signal from a digital video system is intercepted is modeled using full-wave electromagnetic and circuit simulations. For a quantitative evaluation of the eavesdropping threat of display systems and the effect of its countermeasure, the readability of characters on a hypothetical screen as a function of the BER of the recovery signals is presented. It is clear that a decrease of the SNR of the received signal causes a deterioration of the digital video signal-recovery rate and consequently degrades the legibility of the characters on the intercepted screen. It is expected that these techniques can be useful for measurements and analyses of the effects of countermeasures, such as noise jamming or signal modulation, to prevent interceptions of digital video information.

Fast Frequency Sweep Using Asymptotic Waveform Evaluation Technique and Thin Dielectric Sheet Approximation

The thin dielectric sheet (TDS) surface integral equation (SIE) combined with the asymptotic waveform evaluation (AWE) technique is proposed to efficiently analyze wideband properties of thin dielectric layers such as radome and composite materials. The TDS SIE is an efficient method for analyzing the thin dielectric layer because the number of unknowns of the TDS SIE is fewer than that of the volume integral equation (VIE) and the condition number of the TDS impedance matrix is small. In addition, the AWE technique based on a Taylor series and the Pade approximation is a well-known method for fast frequency sweep. Therefore, the combination of these two methods makes analysis of the thin dielectric layer efficient in the wide frequency region because the advantages of each method are shown at the same time. In order to determine the valid bandwidth of the approximated results for arbitrary problems using the TDS combined with the AWE, the bandwidth estimation approach for the AWE is applied. The results of the proposed method for closed and open structures agree very well with the exact solutions and reveal the capability for fast frequency sweep.

Registration sensitivity study of double-layer FSS design for radome

Registration sensitivity study of double-layer cross FSS and 4-legged slot FSS designed for FSS radome was conducted in this paper. Transmission properties, from aligned structure to misaligned structure of half periodicity of unit cell between FSS layers, were discussed. Transmission properties such as center frequency, 3-dB bandwidth and specific characteristic of each misaligned double layer FSS are shown in the paper. The results show that each FSS structure had maximum center frequency transition of 2 GHz and 1.2 GHz and also bandwidth showed change.

Noise-Jamming Effect as a Countermeasure Against TEMPEST During High-Speed Signaling

With digital devices, critical information can be left unsecured due to unintentional emissions from high-speed serial interfaces, such as digital visual interface, high-definition multimedia interface, universal serial bus, and mobile high-definition link. This study presents an analysis of the effectiveness of jamming to offset unwanted information leakage by means of transient electromagnetic pulse emanation surveillance technology from differential signal lines. For a quantitative analysis, a simplified simulation methodology is used to determine the reconstruction rate of the original digital signal as a function of the signal-to-noise ratio of the detected signal for various noise power levels. In addition, the effect of more realistic partial band-noise jamming is studied. It is shown that a jamming signal with a bandwidth ranging from 350 MHz to 3 GHz and with a relatively low level of power can effectively suppress the recovery of information obtained through radio frequency information emanation. This study shows that the band-noise-jamming method using correlated noise with a wide bandwidth is also useful as a countermeasure when considered within the electromagnetic compatibility limitations.

A Method of Superposition for Analysis of the Electrically Large Problem Including Many Vehicles

Commercialization and proliferation of intelligent transport systems (ITS) are progressing worldwide, including vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. Meanwhile, analysis of the related electromagnetic environment is essential for safety-related legislation. However, the theoretical analysis for multiple vehicles poses an electrically large problem and requires enormous computational resources. In this letter, we propose a method of superposition that requires much less computational resources by subgrouping the computational domain and using an efficient post-processing method. The proposed method approximates the original problem by superpositioning the individual subdomain analysis data, including scatterers near the source and observation points. This letter also presents guidelines for applying the proposed method and examples for comparison with full analysis results.

Transmission characteristics of cylindrical dipole infinite array and finite array

Finite periodic array is applied in real situation. But, generally, assumed that periodic structure is arranged infinitely, approximate electromagnetic characteristics can be obtained efficiently. Therefore, comparison and analysis of cylindrical infinite array and cylindrical finite array are required. In this paper, scattering characteristics of cylindrical infinite periodic array are obtained efficiently using cylindrical Floquet harmonics. Also, cylindrical finite periodic array is analyzed using method of moments (MoM) with thin wire approximation because periodic structures which are composed of strip with narrow width are analyzed. Transmission characteristics of each case are obtained and compared.

Transmission characteristics of a composite made with ground granulated blast furnace slag

In this paper, we propose a new composite shielding material using ground granulated blast furnace slag (GGBFS), a byproduct of iron refining. To investigate the feasibility of GGBFS inclusion in shielding material, we fabricated a composite GGBFS material and measured its electromagnetic transmission characteristics. First, we measured the permittivity and permeability of GGBFS itself using a 2-port coaxial cable system. After fabrication of the proposed composite GGBFS material, the permittivity of the proposed structure was measured using the resonance cavity method to obtain the basic electromagnetic material properties. When GGBFS is added to an epoxy resin composite material, permittivity increases by approximately 1.5. To show its feasibility as a shielding material, we fabricated planar samples and measured the electromagnetic transmission characteristics between 6 and 12GHz using the free space measurement method. The results show that the sample’s shielding level is approximately 1.5 dB in the frequency range between 6 and 12GHz for a GGBFS content of 30% and thickness of 2mm. We also obtained a 3 dB (50% of incident power) shielding level at 8.5GHz for a 5mm thick sample. The new proposed material in this paper capable for use in many shielding applications and provide a new opportunity for recycling industrial waste.