EMI of printed circuit board and its modeling

Abstract

SUMMARYMeasurement and modeling of the undesired electromagnetic waves (electromagnetic noise) from electronic devices play an important role in the understanding of EMI problems and in establishing design techniques. One of the methods of analysis of the EMI problems of electronic devices is the measurement of the common mode current flowing in the cables connected to the electronic devices. This paper reviews the measurement of the common mode current on printed circuit boards (PCB) and discusses results related to the EMI problems of PCB. FDTD modeling of the common mode current by traces placed near the PCB edge and suppression of the common mode current by the guard band are described.

Influence of PCB and attached line of hardware on electromagnetic (EM) information leakage

“…A semirigid cable was connected to the center of the PCB in the model, with the upper surface conductor in the PCB connected to the external conductor in the semirigid cable, and the lower surface conductor connected to the center conductor in the semirigid cable. The semirigid cable used for signal input also is an element that determines the resonance frequency occurring in the equipment [12][13][14]. 3, using a 50-Ω semirigid cable.…”

“…1, and to measure the frequency characteristics of the CM current flowing through the information hardware, we used the measurement system shown in Fig. 3, with reference to prior research [11][12][13][14] on EM radiation from PCBs and connected equipment.…”

“…3, using a 50-Ω semirigid cable. Past research [13,14] had shown that this excitation method is equivalent to applying a signal similar to a sinusoidal signal output from a tracking generator between the power source and the ground layer of a piece of equipment. In the present investigation this voltage source was treated as a fluctuation between the ground layer and a power source fluctuating due to eddy currents produced by the LSI in the case of cryptographic processing.…”

“…In prior research, emissions from PCBs connected by cables that represent the primary source of EM radiation from electronic equipment were evaluated [10][11][12][13][14]. A variety of elements make up information hardware.…”

“…Among them, the circuit boards and attached lines (power source cable, cables used for communication with other equipment, wiring inside the equipment) are the most common and essential elements of information hardware. In prior research, emissions from PCBs connected by cables that represent the primary source of EM radiation from electronic equipment were evaluated [10][11][12][13][14]. Thus, in this paper we focus on the circuit board and attached lines as the installation configuration of the information hardware, represent the information hardware by a simple model, and measure the frequency characteristics of the CM currents [8] believed to be a major factor in EM radiation from equipment.…”