JP2639336B2 - High frequency current measurement sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for measuring high-frequency current, and more particularly to a method for measuring current without contact.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration of a conventional high-frequency current measuring sensor.

FIG. 3 is a diagram showing an example of IEEE TRANSAC.
TIONS ON MICROWAVE THEORY
AND TECHNIQUES, VOL. MTT-2
8, NO. 7, JULY, 1980 ". In this figure, the probe 10
1 is connected to the core wire of the coaxial cable 102. The coaxial cable 102 is connected to the detector 51.

Next, the operation principle of the first embodiment will be described. As shown in FIG. 4, when the probe 101 is brought closer to the object to be measured (conductor 103), the component of the electric field generated by the high-frequency current flowing through the conductor 103, which has the same direction as the direction of the probe 101, causes the probe 101 to move. A high frequency current is induced. When the current is detected by the current detector 51, the high-frequency current flowing through the device under test can be known.

FIG. 5 is a diagram showing an example of IEEE TRANSACTION.
NS ON MICROWAVEHEORY AND
TECHNIQUES, VOL. 40, NO. 8, A
UGUST, 1992 ". In the figure, one end of the conductor wire 21 is connected to the conductor tube 11, and the other end is connected to a coplanar line 33 provided on a side wall of the conductor tube 11.
The coplanar line 33 is connected to the detector 51.

Next, the operation principle of the second conventional example will be described. As shown in FIG. 6, when an object to be measured exists immediately below the sensor, a magnetic field generated by a high-frequency current flowing through the object to be measured (conductor 103) is generated so as to surround conductor line 21. Therefore, a component having the same directional component as that of the conductor wire 21 in the high-frequency current flowing through the device under test is
Is induced. If this current is detected by the detector 51, the high-frequency current flowing through the device under test can be known. Also,
When an object to be measured is present away from the sensor as shown in FIG. 7, a magnetic field generated by a high-frequency current flowing through the object to be measured does not surround the conductor wire 21. Therefore, when the object to be measured is far away, the high-frequency current induced in the conductor wire 21 disappears.

[0007]

The sensor for measuring high-frequency current of the prior art 1 reacts to the vertical component of the electric field, so that the magnitude of the high-frequency current flowing through the device under test can be detected. Not detectable.

The high-frequency current measuring sensor of the second conventional example can detect only the magnitude of the high-frequency current in the same direction component as that of the conductor wire 21. Therefore, in order to detect the high-frequency current in the other direction, it is necessary to mechanically rotate the sensor itself by 90 degrees, so that it takes a long time for the measurement.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is not to mechanically rotate a sensor to switch the detection direction of a high-frequency current, but to switch the detection direction electrically. Therefore, the present invention solves the above problems.
Therefore, a high-frequency
In a flow measurement sensor, the end of a straight
1, the second conductor wire is arranged orthogonally, and the first conductor wire is
Are provided with first and second pin diodes in the same direction,
The first and second pins are connected to the second conductor line in the same direction.
Third and fourth pin diodes opposite to the direction of the diode
And a first end of each of the first and second conductor wires is provided.
The other ends of the first and second coaxial cables are connected to the conductor tube.
A sensor unit connected to the first and second coaxial cables;
A bias unit for supplying a bias voltage to the
Detects the high-frequency current of the second coaxial cable and obtains a detection output
And a detector unit. Further, the bias voltage is set to be positive.
Or, by making it negative, the detection direction of the high-frequency current is switched off.
It is characterized by being replaced .

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the principle of the present invention. The sensor part 2 of the high-frequency current measuring sensor is provided at one end of the conductor tube 1.
The conductor wires 21 to 24 are connected in a cross shape, one ends of the PIN diodes 11 and 13 are connected to the conductor tube 1 and the other ends are connected to the conductor wires 21 and 23, respectively.
4 is connected to the coaxial tubes 31 and 32, and the other end is connected to the conductor wires 22 and 2.
4 respectively. The outputs of the coaxial tubes 31 and 32 are
It is connected to a detection output terminal 54 via a detector section 3 composed of high-frequency signal detectors 51 and 52. Further, the coaxial tube 31,
The output of 32 is connected to a bias input 53 via a bias circuit 4 composed of high-frequency blocking inductances 41 and 42.

Next, the operation of the present invention will be described. When a positive voltage is applied to the bias input 53, the PIN diodes 11 and 12 become reverse biased and become nonconductive at high frequencies. On the other hand, the PIN diodes 13 and 14 become forward-biased and become conductive at high frequencies. In this case, as shown in FIG. 2, when the sensor unit 2 of the high-frequency current measuring sensor is moved close to the object, only the current component parallel to the conductor wires 23 and 24 is detected in the current flowing through the object. You. Conversely, when a negative voltage is applied to the bias input,
PIN diodes 11 and 12 become forward biased,
It becomes conductive at high frequencies. On the other hand, PIN diode 1
3 and 14 are reverse biased and become non-conductive at high frequencies. In this case, of the current flowing through the device under test, only the current component parallel to the conductor wires 21 and 22 is detected.

Although a coaxial tube is used for extracting a high-frequency current, a coplanar line may be used.

In this embodiment, the conductor tube 1 is formed of a rectangular parallelepiped. However, as long as the conductor wires 21 to 24 can be connected to one end thereof, the present invention is not limited to this shape. .

[0014]

As described above, in the high-frequency current measuring sensor according to the present invention, the direction of detection of the high-frequency current can be electrically switched by inverting the polarity of the bias input. Therefore, there is no need to mechanically rotate the sensor to switch the detection direction of the high-frequency current.

[Brief description of the drawings]

FIG. 1 is a diagram showing the operation principle of the present invention.

FIG. 2 is a diagram showing one embodiment of the present invention.

FIG. 3 is a diagram showing an example of Conventional Example 1.

FIG. 4 is a diagram showing an operation principle of the sensor of the conventional example 1 shown in FIG.

FIG. 5 is a diagram showing an embodiment of Conventional Example 2.

6 is a diagram illustrating an operation principle in a case where an object to be measured is located immediately below a sensor in Conventional Example 2 illustrated in FIG.

FIG. 7 is a diagram illustrating an operation principle in a case where an object to be measured is located away from a sensor in Conventional Example 2 illustrated in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductor tube 2 Sensor 3 Detector part 4 Bias part 11-14 PIN diode 21-24 Conductor wire 31-32 Coaxial line 33 Coplanar line 41-42 High frequency blocking inductance 51-52 Detector 101 Probe 102 Coaxial cable

Claims (2)

(57) [Claims] 1. A high-frequency current measuring device for measuring a high-frequency current flowing through an object to be measured.
In the frequency current measuring sensor, the first and second conductor wires are orthogonal to the end face of the linear conductor tube.
And the first and second conductor wires are arranged in the same direction in the first and second directions.
And the same as the second conductor wire.
Direction opposite to the direction of the first and second pin diodes
The third and fourth pin diodes are provided, and the first and second pin diodes are provided.
One end of each conductor wire is connected to the conductor tube and the other end is
A bias voltage is supplied to the sensor unit connected to the first and second coaxial cables and the first and second coaxial cables.
And a high-frequency current of the first and second coaxial cables.
A high-frequency current measurement sensor, comprising: a detector for obtaining a wave output . 2. The method according to claim 1, wherein the bias voltage is positive or negative.
A high-frequency current measurement sensor, wherein the detection direction of the high-frequency current is switched .