JP2006220602A - Sensor array for measuring near-field electromagnetic field - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor array for correctly measuring a vicinity of electromagnetic fields, measuring without error in each measured value, even if the electromagnetic field sensor array makes scanning for measurements. <P>SOLUTION: In an electromagnetic sensor array, with a plurality of electromagnetic sensors arranged at constant intervals to measure electromagnetic fields near electronics, the measuring sensor array in the vicinity of electromagnetic fields is provided where the electromagnetic sensors, which do not acquire the desired number of measured data according to the invasive characteristics that disturb the electromagnetic fields by sensors, are arranged at the outermost section of the array. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sensor array for measuring a near electromagnetic field, and in an electromagnetic field sensor array in which a plurality of electromagnetic field sensors are arranged in a grid pattern, by preventing measurement errors caused by the sensor position of the electromagnetic field sensor array, The present invention relates to a sensor installation method for accurately measuring the field.

  In recent years, with the increase in speed and performance of electronic devices, the influence of unnecessary electromagnetic radiation from the electronic devices on other electronic devices has become a problem. The influence of this unnecessary electromagnetic radiation on other electronic devices is called EMI (Electromagnetic Interference), which mainly causes reception failures of wireless devices and communication devices and malfunctions of electronic devices. For this reason, each country regulates unnecessary electromagnetic radiation from electronic devices in the frequency band of 30 MHz to 1 GHz or 30 MHz to 2 GHz, and electronic device manufacturers need to design and manufacture products so as to comply with these regulations. .

  In general, far-field measurement is performed as a method of measuring unnecessary electromagnetic waves. However, far-field measurement does not always identify from which part in an electronic device unnecessary electromagnetic waves are generated. Therefore, a system for measuring an electromagnetic field in the vicinity of an electronic device has been proposed in order to identify an unnecessary electromagnetic wave source and analyze a generation mechanism. For example, Patent Document 1 proposes a printed wiring board.

  FIG. 4 shows an image diagram of a system for measuring a near electromagnetic field on a printed wiring board. The electromagnetic field sensors 101 are arranged in a grid pattern, the sensors are sequentially switched by the sensor switching means 104 that selects the arranged electromagnetic field sensors as needed, the electromagnetic field on the printed wiring board is measured by the measuring device 105, and each measurement is performed. In this system, the measurement value corresponding to the point is displayed by the arithmetic processing and image output device 106 on the electromagnetic field distribution. This system makes it possible to estimate the distribution of high-frequency currents on a printed wiring board, and is used for identification of unnecessary electromagnetic wave sources and analysis of noise generation mechanisms.

  On the other hand, there is a possibility that unnecessary electromagnetic waves are generated by a mechanism different from that of a single printed wiring board for an electronic device main body in which a plurality of printed wiring boards are assembled in a metal casing. Therefore, as in the case of a printed wiring board, Patent Document 2 proposes a near electromagnetic field measurement system corresponding to the measurement of an electronic device in order to analyze an unnecessary electromagnetic wave source and analyze a generation mechanism.

FIG. 5 shows an image diagram of a system for measuring a near electromagnetic field for an electronic device. The electromagnetic field sensor 101 is fixed by a single electromagnetic field sensor fixing jig 501. The electromagnetic field sensor 101 is scanned at an arbitrary measurement region and measurement interval by a scanning unit such as a robot 202 capable of scanning according to the uneven shape of the electronic device, and the electromagnetic field distribution near the electronic device 201 is measured by the measuring device 105. In addition, a system has been proposed in which measurement values corresponding to each measurement point are displayed on the arithmetic processing and image output device 106. Both measurement systems are used as a means to identify the source of unwanted electromagnetic waves, which are difficult to judge only by measuring distant shellfish, and to elucidate the mechanism of noise generation.
Japanese Patent Publication No. 05-067184 JP 2000-230954 A IEICE Technical Report 2002-20 “Examination of electromagnetic field distribution change by magnetic field probe in near magnetic field measurement”

  Here, regarding the characteristics of the shielded loop probe, which is an electromagnetic field sensor mainly used in the near electromagnetic field measurement, as described in Non-Patent Document 1, the probe is arranged close to a predetermined electromagnetic field. The electromagnetic field distribution is disturbed according to the degree of invasiveness of the sensor itself. In the near electromagnetic field measurement system for the entire electronic device, since a single electromagnetic field sensor 101 is scanned over the measurement target as shown in FIG. 5, measurement is performed with the same invasiveness at each measurement point. That is, the change in the electromagnetic field distribution by the electromagnetic field sensor is constant at each measurement point.

  However, as shown in FIG. 2, when using an electromagnetic field sensor array in which a plurality of electromagnetic field sensors are arranged on an electronic device for speeding up the measurement, the electromagnetic field sensor array is used for the same measurement point 301 in FIG. The measurement data was acquired with the electromagnetic field sensor arranged at the outermost periphery as shown in FIG. 3A, and the measurement data was acquired with the electromagnetic field sensor arranged at the center of the array as shown in FIG. In some cases, the degree of invasion is different due to the difference in the number of adjacent electromagnetic field sensors, and thus there is a problem that the measured values are different in each case of FIGS.

  In nearby electromagnetic field measurement, the electromagnetic field distribution before and after the addition of noise countermeasure components may be compared and analyzed to identify the source of unwanted electromagnetic waves and the generation mechanism, and the measurement conditions and environment must always be kept constant. is important. That is, even if the electromagnetic field sensor has invasive characteristics, a comparative study can be performed if the measurement conditions are the same before and after the addition of the noise countermeasure component.

  The near-field electromagnetic field measurement system for printed circuit boards in the prior art is smaller than the electromagnetic sensor array, that is, the measurement area, so if the installation location of the printed circuit board is fixed, the measurement conditions before and after the addition of noise suppression parts Is constant. However, in the case of a large electronic device having a huge number of measurement points, even if an electromagnetic field sensor array is used for speeding up, the measurement area is larger than that of the electromagnetic field sensor array, so the array has to be scanned. .

  The present invention has been made in view of such problems, and an object thereof is to provide a sensor array for measuring a near electromagnetic field that enables accurate measurement in a state in which a plurality of nearby electromagnetic field sensors are arranged. To do.

  In order to achieve the above object, a sensor array for measuring a near electromagnetic field according to the present invention is designed so that the degree of invasiveness of the electromagnetic field sensor is uniform in the measurement region in accordance with the invasive characteristics that the sensor disturbs the electromagnetic field. An electromagnetic field sensor that does not acquire the desired number of measurement data is installed on the outer periphery. As a result, it is possible to accurately measure the electromagnetic field in the vicinity of the electronic device without different measurement values at the center and the outer periphery of the sensor array in the measurement at the same point.

  Further, the first invention of the present invention will be described as follows.

  (1) In an electromagnetic field sensor array in which a plurality of electromagnetic field sensors are arranged at regular intervals in order to measure an electromagnetic field in the vicinity of an electronic device, the sensor is desired on the outermost periphery of the array according to the invasive characteristics that disturb the electromagnetic field. A sensor array for measuring a near electromagnetic field, characterized in that electromagnetic field sensors that do not acquire measurement data for the number of the electromagnetic fields are installed.

  The sensor array for measuring the near electromagnetic field according to the present invention provides the same sensor as the electromagnetic field sensor used for the measurement on the outer periphery of the array, thereby preventing an error in the measured value at the sensor position caused by the degree of invasiveness of the electromagnetic field sensor. It is possible to accurately measure the nearby electromagnetic field.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  A sensor array for measuring a near electromagnetic field according to the present invention will be described with reference to FIG. In a sensor array in which a plurality of nearby electromagnetic field sensors 101 are arranged at a constant interval having an arbitrary distance, in order to create a uniform electromagnetic field invasion degree over the entire measurement region according to the degree of invasion of the electromagnetic field sensor used, The same electromagnetic field sensor as the measurement electromagnetic field sensor 101 is arranged on the outermost periphery of the array. The sensor 102 arranged on the outermost periphery is fixed by the same cable fixing jig 103 as the electromagnetic field sensor for measurement, and wired with the same cable length. The electromagnetic field sensor for measurement is connected to the switching means 104 for sequentially selecting the sensors and is connected to the measuring device 105, and the measured value of each measured electromagnetic field sensor position is output by the arithmetic processing and image output device 106.

  On the other hand, the sensor arranged on the outermost periphery is terminated by a terminator 107 having the same impedance as that of the measurement system. This structure realizes a uniform degree of invasiveness of the electromagnetic field sensor in the measurement region.

  As a result, when the measurement target is larger than the measurement region of the electromagnetic field sensor array such as the large electronic device shown in FIG. 2, it is necessary to scan the electromagnetic field sensor array to perform measurement. A measurement environment can be realized in which accurate measurement is performed without different measurement values depending on the position of the sensor.

Explanatory drawing of the Example of this invention Explanatory drawing of the Example of this invention Explanatory drawing of the Example of this invention Image of a system that measures the near electromagnetic field on a conventional printed wiring board Image of a system for measuring near electromagnetic fields for conventional electronic devices

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Electromagnetic sensor 102 for measurement Electromagnetic field sensor 103 for making measurement surface uniform invasive degree Electromagnetic field sensor array fixing jig 104 Electromagnetic field sensor switching means 105 Measuring device 106 Arithmetic processing and image output device 107 Terminator 201 Electronic device 202 Sensor scanning robot 301 Measuring point 302 Electronic device housing 303 Printed wiring board 401 connected to electronic device housing Printed wiring board 501 Electromagnetic field sensor fixing jig

Claims (2)

  In an electromagnetic field sensor array in which a plurality of electromagnetic field sensors are arranged at regular intervals in order to measure the electromagnetic field in the vicinity of an electronic device, a desired number of sensors are arranged on the outermost periphery of the array according to the invasive characteristics that disturb the electromagnetic field. A sensor array for measuring a near electromagnetic field, wherein an electromagnetic field sensor that does not acquire measurement data is installed.   The near electromagnetic field measuring sensor array according to claim 1, wherein an electromagnetic field sensor that does not acquire measurement data installed on the outermost circumference of the array is terminated with an impedance of a measurement system. Sensor array for field measurement.