JP3123907B2 - Electromagnetic radiation measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic radiation measuring device used for measuring electromagnetic radiation from printed circuit boards and circuit devices.

[0002]

2. Description of the Related Art In recent years, regulations have been established in many countries in order to minimize interference caused by unnecessary radiation generated from various electronic devices. For example, overseas, FCC (United States Federal Communications Commission), Standards such as CISPR (International Special Committee on Radio Interference) and VDE (German Institute of Electrical Engineers) have been established. In Japan as well, the voluntary standards of VCCI (Voluntary Council for Prevention of Interference by Information Processing Equipment) have been determined, and electronic device manufacturers are taking measures to suppress unnecessary radiation generated from various electronic devices. . These unnecessary radiation regulations are generally established for each frequency over a wide range from 30 MHz to 1 GHz. In addition, the measurement method measures the electric field strength at a position separated by a predetermined distance from the electronic device that is a source of unnecessary radiation, and the measurement environment and measuring instruments are special, so costs are generally low. It becomes bulky. Also, the measurement technique requires considerable expertise.

Recently, in order to reduce the time and cost for measuring unnecessary radiation and taking countermeasures for electronic equipment as described above, recently, the intensity of a nearby electromagnetic field radiated from a printed circuit board or similar circuit device of the electronic equipment has been reduced. A simple electromagnetic radiation measuring device for measuring the temperature is used. In these simple electromagnetic radiation measuring devices, a large number of electromagnetic radiation detecting means are arranged in order to identify a portion (print pattern) having a high electromagnetic radiation level on a printed circuit board and electronically sequentially selected. The measurement method is adopted.

Conventionally, such an electromagnetic radiation measuring apparatus has been
As described in JP fairness 5-67184, and converted into an electric signal by detecting the electromagnetic radiation by the wire loop antenna by printed patterns formed on the multilayer printed circuit board, and electronically sequentially switched by diodes It is configured to be added to the transmission line. Also,
By arranging a large number of rows of electromagnetic radiation detectors constituted by a large number of wire loop antennas and one transmission line, and selecting the respective transmission line outputs in the signal selection unit, about 1000 wire loop antennas are provided. Some are configured to switch electronically sequentially, so that the electromagnetic radiation level at an arbitrary position on a printed circuit board can be measured.

FIG. 2 is a diagram showing the configuration of an electromagnetic radiation detecting section of a conventional electromagnetic radiation measuring apparatus. An electromagnetic radiation detecting section 4 is constituted by the wire loop antenna 1, the switching diode 13, and the transmission line 3. The electromagnetic radiation detected by the wire loop antenna 1 is converted into an electric signal and transmitted through the switching diode 13. By applying a voltage to the line 3 and applying a voltage to the Y-direction control signal terminal 5, the switching diode 13 is turned on, and the wire loop antenna 1 at the selected Y-direction position is turned on.
Only the transmission line 3 is electrically connected. Similarly, by applying a voltage to another Y-direction control signal terminal, another Y-direction position can be selected.

As described above, in the prior art, the signal detected by the wire loop antenna is connected to the transmission line by the switching diode.
No signal amplification is performed at the wire loop antenna.

[0007]

However, in the above prior art, since there is a proportional relationship between the aperture area of the wire loop antenna and the sensitivity, in order to secure a practical level of sensitivity, for example, a wire loop antenna is required. The size of one side of the antenna needs to be about 7 mm, and there is a problem that it is difficult to improve the position resolution of the electromagnetic radiation measurement and to reduce the size of the measurement device. Also, since the sensitivity of the wire loop antenna itself is low, the level difference between the desired measurement signal from the wire loop antenna and the signal leaking into the transmission line, signal selection unit, output unit, etc. There has been a problem that it is not possible to obtain a high level and it is not possible to widen the dynamic range of the detection level.

According to the present invention, the sensitivity of the wire loop antenna itself, which is a means for detecting electromagnetic radiation, is improved, thereby improving the detection sensitivity and dynamic range, and securing the predetermined sensitivity and the dynamic range of the detection level. Above, by reducing the shape of the wire loop antenna, improve the position resolution of electromagnetic radiation measurement,
It is another object of the present invention to provide an electromagnetic radiation measuring device having a reduced size.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a multiplicity of independent amplifying elements corresponding to ones of a plurality of small antenna sections each having a wire loop antenna. , The sensitivity of the antenna itself is improved by amplifying the output level from the antenna, and the wire loop antenna is switched electronically sequentially by individually controlling the amplifying elements. Things.

Therefore, according to the present invention, by amplifying the output level from the minute antenna section by the amplifying element, the sensitivity of the minute antenna section itself can be improved, and the detection sensitivity and the dynamic range can be improved. it can. In addition, the shape of the wire loop antenna required to obtain the predetermined sensitivity can be reduced, and the wire loop antenna is electronically switched by individually controlling the amplifying elements. Therefore, it is possible to provide an electromagnetic radiation measuring device in which the minute antenna portion is downsized to improve the position resolution of the electromagnetic radiation measurement and the device is downsized.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a minute antenna element formed on a multilayer printed circuit board and formed of a conductor pattern, and a minute antenna element mounted near the minute antenna element. in small antenna portion and a constant spacing to one transmission line path of the output terminal of the amplifying element of each small antenna unit as well as sequence number of small antenna portion having an amplifier element having an input terminal connected to the output of the antenna elements An array of connected electromagnetic radiation detectors, a plurality of rows of electromagnetic radiation detectors, and a signal selector for selecting an output of the electromagnetic radiation detectors are provided, and the operation of the amplifying element of each small antenna unit is controlled. This is an electromagnetic radiation measuring device that electronically sequentially selects a large number of small antenna elements and outputs the electronic signals via a transmission line and a signal selector, and detects electromagnetic radiation. By improving the sensitivity of the wire loop antenna itself, which is a means for improving the detection sensitivity and the dynamic range, and securing the predetermined sensitivity and the dynamic range of the detection level, the size of the wire loop antenna is reduced. This can improve the position resolution of the electromagnetic radiation measurement and reduce the size of the device.

According to a second aspect of the present invention, a plurality of minute antenna elements are sequentially selected electronically by using a transistor as an amplifying element of the small antenna section and controlling a bias voltage of the transistor. Thus, the apparatus can be further downsized.

According to a third aspect of the present invention, a transistor is used as an amplifying element of a small antenna unit, a base of the transistor is connected to a minute antenna element, a collector is connected to a transmission line, and an emitter is grounded. By connecting and controlling the base bias voltage, a large number of minute antenna elements are sequentially selected electronically, so that the device can be further miniaturized.

According to a fourth aspect of the present invention, a large number of minute antenna elements are electronically controlled by using a field effect transistor as an amplifying element of a small antenna unit and controlling a bias voltage of the field effect transistor. Are sequentially selected, and the size of the apparatus can be further reduced.

According to a fifth aspect of the present invention, a field effect transistor is used as an amplifying element of a small antenna unit, a gate of the field effect transistor is connected to a minute antenna element, and a drain is connected to a transmission line. By connecting the source to the ground and controlling the gate bias voltage, a large number of minute antenna elements are sequentially selected electronically, and the device can be further miniaturized.

(Embodiment) FIG. 1 is a block diagram showing a configuration of an electromagnetic radiation measuring apparatus according to an embodiment of the present invention. Those having the same functions as those of the conventional example shown in FIG. The code is attached. This electromagnetic radiation measurement device
Generally, it is formed on a multilayer printed circuit board having a thickness of about 4 mm. In FIG. 1, reference numeral 1 denotes a wire loop antenna formed of a copper foil pattern of about 6 to 7 mm formed on a printed circuit board. Reference numeral 2 denotes a transistor 2 which is an amplifying element surface-mounted on a surface layer of a printed circuit board, and has a wire loop antenna 1 connected to its base. Reference numeral 3 denotes a transmission line connected to the collector of the transistor 2 and formed on an inner layer of the printed circuit board. The emitter of transistor 2 is connected to ground. Reference numeral 4 denotes an electromagnetic radiation detection unit row constituted by the above elements,
Normally, about 20 to 40 electromagnetic radiation detection units composed of a combination of the wire loop antenna 1 and the transistor 2 are arranged in one electromagnetic radiation detection section row 4. 5 is X
A Y-direction control signal terminal connects each of the wire loop antennas 1 arranged in the direction, and 6 is a terminating element. 7
Is a DC blocking capacitor, 8 is an output terminal of each of the electromagnetic radiation detecting rows 4, 9 is a signal selecting section for selecting an output of any of the electromagnetic radiation detecting rows 4, 10 switching diodes, 1
1 is a transmission line, and 12 is an output terminal of the device.

Next, the operation of the electromagnetic radiation measuring apparatus configured as described above will be described. Electromagnetic radiation detected by the wire loop antenna 1 is converted into an electric signal and input to the base of the transistor 2. Here, by applying a voltage to the Y-direction control signal terminal 5, the transistor 2 is turned on, and the detection output of the wire loop antenna 1 is amplified and transmitted to the transmission line 3. At this time, another Y
Since no voltage is applied to the direction control signal terminal 5, the other wire loop antenna 1 and the transistor 2 are not selected, and the output is not transmitted to the transmission line 3. Similarly, by applying a voltage to only one of the other Y-direction control signal terminals 5, another Y-direction position can be selected.
The termination block 6 terminates the transmission line 3 at the characteristic impedance of the transmission line 3 (generally 50 ohms). The capacitor 7 blocks direct current of the signal output from the transmission line 3 and transmits the signal to the output terminal 8 of the electromagnetic radiation detecting section 4.

By arranging about 50 electromagnetic radiation detecting section rows 4 in the X direction, a minute antenna section composed of a combination of the wire loop antenna 1 and the transistor 2 is arranged in the X direction.
1000 to 2000 pieces are arranged in a matrix in the −Y direction. By electronically selecting these minute antenna portions sequentially and measuring the electromagnetic radiation level, the electromagnetic radiation intensity distribution of the object to be measured such as a printed circuit board can be measured. That is, the output terminal 8 of the electromagnetic radiation detection section row 4
Are arranged in the X direction, and each of the outputs is selected by the signal selector 9 and output from the output terminal 12 of the device to an external level meter or the like. The signal selecting section 9 is composed of a transmission line 11 and a switching diode 10. The signal from the output terminal 8 of the electromagnetic radiation detecting section 4 follows a single path with each contact as a crossroad, and outputs the signal from the output terminal of the apparatus. Lead to 12.

As described above, in the electromagnetic radiation measuring apparatus according to the above embodiment, the electric signal detected by the wire loop antenna 1 is input to the base of the transistor 2 in the operating state, and is amplified with a gain of, for example, 5 dB to 10 dB. Then, the amplification effect of the transistor 2 enhances the sensitivity of the small antenna unit, and the transmission line 3 and the signal selection unit, which are the path for transmitting the desired measurement signal from the wire loop antenna 1 and the signal, are transmitted. 9, a high level difference from the leak signal to the signal 9 can be obtained, and the dynamic range of the detection level can be widened. In addition, the size of the wire loop antenna 1 is increased by the amount by which the sensitivity is increased by the amplification effect of the transistor 2,
Since the size can be reduced to, for example, 5 mm or less, the position resolution of the electromagnetic radiation measurement can be improved and the measurement device can be reduced in size. Further, by reducing the size of the wire loop antenna 1 to 5 mm or less, the inductance of the wire loop itself can be reduced, so that the detection sensitivity can be secured up to a high frequency range of, for example, 2 GHz or more, and the frequency characteristic of the electromagnetic radiation measurement can be secured. Can also be improved.

In the above embodiment, a transistor is used as an amplifying element. However, the present invention is not limited to this. For example, a similar effect can be obtained by a high-frequency low-noise amplifying element such as a field effect transistor. .

[0021]

The present invention exhibits, as apparent et or above embodiment, it is possible to improve the sensitivity of the micro-antenna unit itself by amplified by the amplifying element the output level from the small antenna unit, the detection sensitivity And the dynamic range can be improved. In addition, since the shape of the wire loop antenna required to obtain a predetermined sensitivity can be reduced, and the wire loop antenna is sequentially switched electronically by separately controlling the amplifying element,
The switching element can also be used, and the minute antenna unit can be miniaturized to improve the position resolution of the electromagnetic radiation measurement, and to provide an electromagnetic radiation measuring device in which the device is downsized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electromagnetic radiation measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an electromagnetic radiation measuring apparatus according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire loop antenna 2 Transistor 3 Transmission line 4 Electromagnetic radiation detection part row 5 Y direction control signal terminal 6 Termination element 7 DC blocking capacitor 8 Output terminal 9 Signal selection part 10 Switching diode 11 Transmission line 12 Device output terminal 13 Switching diode

Claims (5)

(57) [Claims] 1. A small antenna element formed on a multilayer printed circuit board and configured by a conductor pattern, and an amplifying element mounted near the small antenna element and having an input terminal connected to an output of the small antenna element. a small antenna portion having bets, as well as sequence number of the small antenna portion, and an electromagnetic radiation detector rows connected at regular intervals the output terminal of the amplifying element of each small antenna portions to one transmission line path, said electromagnetic Along with arranging multiple rows of radiation detection units,
A signal selection unit for selecting the output of the electromagnetic radiation detection unit row, by controlling the operation of the amplifying element of each of the small antenna unit, electronically sequentially select the large number of small antenna elements, An electromagnetic radiation measuring device for outputting through a transmission line and a signal selector. 2. The method according to claim 1, wherein a transistor is used as an amplifying element of the small antenna unit, and a plurality of minute antenna elements are sequentially selected electronically by controlling a bias voltage of the transistor. Electromagnetic radiation measuring equipment. 3. A transistor is used as an amplifying element of a small antenna unit, a base of the transistor is connected to a minute antenna element, a collector is connected to a transmission line, and an emitter is connected to ground to control a base bias voltage. 2. The electromagnetic radiation measuring apparatus according to claim 1, wherein a plurality of minute antenna elements are selected electronically one after another. 4. An electric field effect as an amplifying element of a small antenna unit.
2. The method according to claim 1, wherein a plurality of minute antenna elements are sequentially selected electronically by controlling a bias voltage of the field effect transistor using a transistor.
Electromagnetic radiation measuring device as described. 5. A field effect transistor is used as an amplifying element of a small antenna unit, a gate of the field effect transistor is connected to a small antenna element, a drain is connected to a transmission line, and a source is connected to ground, and a gate bias is applied. 2. The electromagnetic radiation measuring apparatus according to claim 1, wherein a plurality of small antenna elements are sequentially selected electronically by controlling a voltage.