Chiharu Miyazaki

Effect of a shielding plane connected to ground plane of a PCB in EMI reduction

Effect of a shielding plane used for suppressing emission from a PCB is experimentally studied in this paper. The shielding plane is connected to some points of a ground plane contained in the PCB. In many cases of products, cables extend out of the shielding area and signal traces exist outside of this area. These cables and signal traces cancel the effect of shielding the devices inside of the shielding area. Moreover, in these cases, an extended shielding plane increases radiation level from the PCB.

A round-robin test on effectiveness of a VHF LISN for radiated emission measurements

VCCI Technical Sub-committee has investigated the dispersion of radiated emission measurement results. It was confirmed that one of the main cause of the dispersion of radiated emission measurement results was the difference of the power line-to-ground impedance of the power supply for the equipment under test (EUT). For the improvement of the dispersion, VCCI Council manufactured the experimental VHF LISN (Very High Frequency Line Impedance Stabilization Network). And we performed a round-robin test on the effectiveness of the VHF LISN.

Improvement of dispersion of radiated emission measurement results by VHF-LISN

VCCI* Technical Sub-committee has investigated the dispersion of radiated emission measurement results . It was confirmed that one of the main cause of the dispersion of radiated emission measurement results was the difference of the power line-to-ground impedance of the power supply for the equipment under test (EUT). For the improvement of the dispersion, VCCI manufactured the experimental VHF-LISN (very high frequency-line impedance stabilization network). And we confirmed the validity of this VHF-LISN.

Driver/receiver IC models for simulation of normal-mode emission

The authors are developing the technology that can simulate normal-mode emission radiated from printed circuit boards. We describe the driver and the receiver IC models which are needed to simulate radiated emission. We have derived the driver and the receiver IC models. The validity of these models was confirmed by comparing measured data with the results of the simulation.

Design of electromagnetic field immunity test system applying with 128-element array antenna

We examined about the electromagnetic field immunity test system applying the array antenna technology. This system is able to get the high uniformity of electric field and the high power electric field near the antenna, in a wideband, by the beam forming technology. This system applied the array antenna technology which is constructed by 128-element array antenna with low price and low power amplifiers. To develop this system, we calculated the relationship among the electric field uniformity, the electric field strength, the curvature radius of the array antenna, and the distance from the antenna to uniform field area (UFA). Then, we designed and constructed this system. In this paper, we explain these considerations and characteristics of this system.

Experimental Evaluation of Isolation Effect on Printed Circuit Board with Gapped Power Plane

When the digital and the analog circuits are mounted on a printed circuit board (PCB), the gapped digital and analog power planes are often used as the isolation method. In this case, three layers (digital power plane, ground plane, analog power plane) are needed for a perfect isolation between a digital power plane and an analog power plane. However, if it is possible to allocate only two layers for these three planes, the gapped planes in the same layer are used as the power planes. The gapped planes cause an increase of a radiation because the electromagnetic noise on one power plane couples to another power plane. In order to suppress a radiation, it is necessary to isolate both power planes. For this reason, the isolation method was estimated experimentally. And we estimated radiation from PCB with various gapped planes.

Investigation of Radiated Emission Measurement Method above 1 GHz

The limits and the measurement methods for the radiated emissions above 1 GHz have been published as CISPR22 Ed. 5 Amendment 1 and CISPR16-2-3 Ed. 1 Amendment 1, respectively, VCCI Technical Sub-committee has examined the measurement methods for the radiated emissions above 1 GHz. This paper describes the matter of the signal to noise ratio (S/N) for the radiated emission measurement system above 1 GHz, the setting for the video band width (VBW) of a spectrum analyzer and the influence that the rotational speed of a turntable and the sweep time of a spectrum analyzer exert on radiated emission measurement above 1 GHz, based on the measurement results.

Radiated emission from a power plane of a multilayer printed circuit board

This paper describes radiated emission from a power plane of multilayer printed circuit boards (PCBs). A multilayer PCB has power planes, ground planes and signal planes. Emission from a power plane contributes to measurement results of emission from PCB. Measurements are made of emissions from multilayer PCBs, which have various lengths power plane areas. The authors examined the influence of the power plane only on radiated emissions.

Deterioration in shield characteristics by signal lines and power lines passing through shield material

The authors are developing the technology for designing shields of electronic equipment. As a factor which deteriorates shield characteristics, we pay attention to signal lines and power lines passing through a shield material. In this paper, we describe the effects of these lines on shield characteristics.