We have developed an algorithm called the "spectral-domain-to-real-space approach" (SDRSA) to analytically calculate radiation from the two-dimensional current density distribution in microstrip line configurations where the microstrip lines are represented in the form of a three-dimensional inhomogeneous structure. The algorithm is based on the spectral-domain approach used to estimate radiation from microstrip line configurations. Calculation results obtained by using the SDRSA and the current density distribution from a quasi-TEM mode model of microstrip lines agree well with the corresponding estimations obtained by using the equivalent electric current source method and the magnetic current source method, and with the experimental results obtained in the frequency band of up to 1 GHz.

This paper is consisting of the two novel EMC technologies that we have been developed in our laboratory. The first is the technology for measuring the RF (Radio Frequency) nearby magnetic field and estimation of the RF current in the printed circuit board (PCB) by using the small loop antenna with multi-layer PCB structure developed by our laboratory. I introduce the application of our small loop antenna with its physical structure and the analysis of the nearby magnetic field distribution of the printed circuit board applying the discrete Wavelet analysis. We can understand the behavior of the digital circuit in detail, and we can also take measures to meet the specification about the electromagnetic radiation from the digital circuit from the higher order of priority by using these technologies. The second is our proposing novel technology for reducing the electromagnetic radiation from the digital equipment by taking notice of the improvement of the de-coupling in the PCB. We confirmed the remarkable effect of this technology by redesigning the motherboard of the small-sized computer.

Digitalization in electronic systems requires the electronics devices in de-coupler sets with low impedance at high frequency, and high reliability. A shield strip type line component with aluminum substrate, its surface oxidized dielectric layer and a conducting polymer electrolyte has been developed. The conducting polymers of polypyrrole and poly(3,4-ethylenedioxythiophene) have been formed by direct chemical oxidative polymerization and electrochemical polymerization on a dielectric layer. Thus, the surface of the dielectric layer is covered with conducting polymer films. The structure of the line component is strip line conformation just like a crushed coaxial cable with in-put and out-put terminals surrounded by the conducting polymer electrolyte. Two types of the components, i.e., a large surface area, 10 20 mm, and a small surface area, 4 4 mm, have been fabricated with polypyrrole and poly(3,4-ethylenedioxythiophene), respectively. The dielectric properties of these line components have been investigated with a Impedance/Gain-phase analyzer and a network analyzer. Due to the high conductivity of the polymer electrolytes, the line components demonstrate low impedance at resonance frequency. Regarding the frequency characteristics of the line components, the impedance and ESR at high frequency are lower than those of the conventional capacitors. Furthermore, the transfer coefficients, S21, are three orders lower than those of other capacitors in a wide frequency band from 10 kHz to 6 GHz. The results indicate the excellent characteristics of the line components for the power line de-coupler set at the boundary of the closed circuit unit.