KR102854195B1 - Radio frequency voltage current sensor - Google Patents

Abstract

The present invention relates to a novel RF voltage and current sensor that facilitates scaling of measured voltage and current, comprising: a detection substrate having a circular opening through which a transmission line transmitting an RF (Radio Frequency) signal passes; a plurality of voltage detection electrodes installed on the detection substrate along the periphery of the opening, the plurality of arc-shaped conductors capacitively coupled to the core of the transmission line being spaced apart from each other with a predetermined gap; a plurality of via holes formed on a plurality of concentric circles formed radially outwardly with different radii centered on the opening of the detection substrate; a current detection coil formed of a conductor wound through the plurality of via holes, the current detection coil forming a secondary coil inductively coupled to the core of the transmission line; and a sensing circuit unit installed on the detection substrate, the sensing circuit unit converting a voltage applied between at least one electrode of the plurality of voltage detection electrodes and a ground side into a predetermined voltage level and outputting the voltage, and converting a current induced in the current detection coil into a predetermined current level and outputting the voltage.

Description

RF voltage current sensor {RADIO FREQUENCY VOLTAGE CURRENT SENSOR}

The present invention relates to an RF voltage current sensor for measuring voltage and current for a transmission line transmitting an RF signal, and more particularly, to a novel RF voltage current sensor that facilitates scaling of measured voltage and current.

Plasma power supplies are used in a variety of industrial fields. For example, plasma power supplies are used in semiconductor and display manufacturing processes such as etching, deposition, and ashing. A plasma power supply generates high-frequency power and supplies it to a chamber, which acts as a plasma load. This generates a plasma discharge in the gas atmosphere within the chamber, enabling processes to proceed using the activated gas.

The output impedance of a plasma power supply is typically fixed at 50 ohms, while the impedance of the plasma load fluctuates constantly. When the impedances of the power supply and load are aligned, reflected waves from the plasma load back to the power supply can be reduced, preventing damage to the power supply caused by reflected waves and ensuring that RF power is fully utilized within the chamber.

For example, in a plasma power supply, the voltage and power of the RF (Radio Frequency) power directed at the plasma load are measured, and the frequency of the power supply is varied based on the measured value, or the impedance of the power supply is varied using an impedance matching device, thereby reducing reflected waves. To control the plasma power supply in this way, accurate voltage and current measurements from the RF transmission line are essential.

Typically, RF voltage and current sensors are installed where RF transmission lines pass. The RF voltage and current sensors have a structure in which a voltage detection unit and a current detection unit are respectively installed on a PCB (Printed Circuit Board) through which the transmission line passes through an opening in the center. The voltage detection unit is formed as a conductive ring-shaped electrode with a metal plated on the inner surface of the opening of the PCB so as to capacitively couple with the core (conductor) of the transmission line. The current detection unit is provided in the form of a Rogowski coil installed on the PCB that is inductively coupled to the transmission line. A conversion circuit is installed on the PCB that converts the signals detected by the voltage detection unit and the current detection unit into predetermined voltage and current levels, respectively. The voltage and current output from the conversion circuit are used to monitor the forward wave power or reflected wave power of the RF signal.

Most RF voltage and current sensors are modular, with measured voltage and current ratings determined by the RF power flowing through the transmission line. However, power supply power varies depending on the plasma load, and in some cases, multiple power supplies are combined to adjust the power supply stage. Therefore, the measurement scale of the RF voltage and current sensor must be adjusted accordingly. Previously, the RF voltage and current sensor had to be replaced whenever the power supply changed, which was a hassle.

Republic of Korea Patent Registration No. 10-1099663 Republic of Korea Patent Registration No. 10-1257980 Republic of Korea Patent Registration No. 10-1787420

The purpose of the present invention is to provide an RF voltage current sensor that can easily perform scaling of a measured voltage without replacing a sensor by installing a plurality of arc-shaped voltage detection electrodes that are capacitively coupled to the core of a transmission line and selectively controlling the number of connections between the voltage detection terminal and the voltage detection electrodes.

In addition, the present invention has another purpose of providing an RF voltage current sensor that can facilitate scaling of a measured current by installing a plurality of current detection coils wound in a first direction and a current canceling coil wound in a second direction opposite to the first direction, and selecting a combination of cross-connecting the current detection coils or connecting them by bypassing the current canceling coils.

According to one embodiment of the present invention, an RF voltage current sensor comprises: a detection substrate having a circular opening through which a transmission line transmitting an RF (Radio Frequency) signal passes; a plurality of voltage detection electrodes installed on the detection substrate along the periphery of the opening, and having arc-shaped conductors spaced apart from each other with a predetermined gap, the arc-shaped conductors being capacitively coupled to the core of the transmission line; a plurality of via holes formed on a plurality of concentric circles formed radially outwardly with different radii centered on the opening of the detection substrate; a current detection coil formed of a conductor wound through the plurality of via holes, the current detection coil forming a secondary coil inductively coupled to the core of the transmission line; and a sensing circuit unit installed on the detection substrate, the sensing circuit unit converting a voltage applied between at least one electrode of the plurality of voltage detection electrodes and a ground side into a predetermined voltage level and outputting the voltage, and converting a current induced in the current detection coil into a predetermined current level and outputting the voltage.

In another embodiment of the present invention, an RF voltage current sensor has a plurality of arc-shaped holes formed around an opening of the detection substrate and spaced apart from the opening, and a conductive metal body is filled in each of the holes to form the voltage detection electrode.

In another embodiment of the present invention, an RF voltage current sensor is provided, wherein each of the voltage detection electrodes has an arc shape of different length.

According to another embodiment of the present invention, an RF voltage current sensor further includes a plurality of voltage scale switches, wherein the sensing circuit unit is individually installed between each of the voltage detection electrodes and the voltage detection terminal and switches the connection between the voltage detection electrodes and the voltage detection terminal.

According to another embodiment of the present invention, an RF voltage current sensor comprises a plurality of current detection coils each of which is formed of a conductor wound through the via holes in different regions, and further comprises at least one current canceling coil formed of a conductor wound through the via holes in an opposite direction to the current detection coil between the current detection coils, and a scale of a measured current can be adjusted by selecting a connection between the current detection coil and the current canceling coil.

According to the RF voltage current sensor of the present invention, a plurality of arc-shaped voltage detection electrodes capacitively coupled to the core of a transmission line are installed, and the number of connections between the voltage detection terminal and the voltage detection electrodes is selectively adjusted, thereby facilitating scaling of the measured voltage without replacing the sensor.

In addition, according to the RF voltage current sensor of the present invention, there is an effect of facilitating scaling of the measured current by installing a plurality of current detection coils wound in a first direction and a current canceling coil wound in a second direction opposite to the first direction, and selecting a combination of cross-connecting the current detection coils or connecting them by bypassing the current canceling coils.

Figure 1 is a front view illustrating an RF voltage current sensor according to the present invention;
Figure 2 is a drawing showing an example of configuring the RF voltage current sensor in maximum current measurement mode.
Fig. 3 is an equivalent circuit diagram showing an example of configuring the RF voltage current sensor in maximum current and maximum voltage measurement mode.
Figure 4 is a drawing showing an example of configuring the RF voltage current sensor in minimum current measurement mode.
Fig. 5 is an equivalent circuit diagram showing an example of configuring an RF voltage current sensor in maximum current and minimum voltage measurement modes, and
Fig. 6 is an equivalent circuit diagram showing an example of switching control of voltage and current measurement scales.

Hereinafter, specific embodiments of the present invention will be described with reference to the attached drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention are included.

Parts having similar configurations and operations throughout the specification are designated by the same drawing reference numerals. The drawings attached to the present invention are provided for convenience of explanation, and their shapes and relative scales may be exaggerated or omitted.

In describing the embodiments in detail, redundant descriptions or descriptions of techniques obvious in the art have been omitted. Furthermore, when a part of the following description is said to "include" another component, this means that, unless otherwise specifically stated, the described component may include additional components.

Additionally, terms such as "part," "device," and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented through hardware, software, or a combination of hardware and software. Furthermore, when a part is said to be electrically connected to another part, this includes not only cases where they are directly connected, but also cases where they are connected with another component in between.

Terms that include ordinal numbers, such as "first" and "second," may be used to describe various components, but these components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a second component could be referred to as a "first component," and similarly, a first component could be referred to as a "second component."

The RF voltage current sensor according to the present invention is a sensor that is installed on a transmission line that transmits radio frequency (RF) power, that is, power having a frequency of 10 kHz or higher, and measures the voltage and current of the power passing through the transmission line. For example, the RF voltage current sensor of the present invention is installed to measure the forward wave or reflected wave power at the output terminal of a plasma power supply device. In addition, the RF voltage current sensor of the present invention can be installed at other locations such as the high-frequency power generation side of a plasma power supply system, the power input side of a load, and can also be installed in other industrial fields where radio frequency power passes.

Fig. 1 is a front view illustrating an RF voltage current sensor according to the present invention. Referring to Fig. 1, the RF voltage current sensor according to the present invention is installed on a detection substrate (100) having a circular opening (110) through which a transmission line transmitting an RF signal passes.

Although not shown in Fig. 1, the transmission line (150) depicted in the equivalent circuit diagrams of Figs. 3, 5, and 6 is a line that transmits an RF signal, and is a line formed by having a conductor core that transmits high-frequency power at the center and covering the outside of the core with an insulating outer sheath.

Referring to FIG. 1, components such as electrodes, detection lines, and coils for detecting voltage and current from a transmission line are installed in the upper region of the detection substrate (100), and a sensing circuit unit (130) is installed in the lower region to convert the detected voltage and current into a predetermined transformation ratio and current ratio and output the measured voltage and current levels. A sensor output port (132, 134) is installed at an end of the sensing circuit unit (130). The sensor output port (132, 134) is a port that transmits a sensor output signal detected by the RF voltage and current sensor of the present invention to an external device (e.g., a monitoring system or power controller of a plasma power supply device, etc.).

Referring to Fig. 1, a voltage detection unit that is capacitively coupled to the core of a transmission line (150) and a current detection unit that is inductively coupled are formed in the upper region of the detection substrate.

First, the components of the voltage detection unit are explained.

A plurality of voltage detection electrodes (210, 220, 230) are installed along the perimeter of the opening (120) on the detection substrate (100). As illustrated, three voltage detection electrodes (210, 220, 230) may be installed. The first voltage detection electrode (210), the second voltage detection electrode (220), and the third voltage detection electrode (230) are each formed as arc-shaped conductors spaced apart from each other with a predetermined gap. As an example, the three voltage detection electrodes (210, 220, 230) have the same facing area with respect to the core of the transmission line (150). As another example, the three voltage detection electrodes (210, 220, 230) may be formed as arc-shaped structures of different lengths to have different facing areas with respect to the core of the transmission line (150).

Referring to Fig. 1, three arc-shaped holes spaced apart from the opening (120) of the detection substrate (100) are formed around the opening (120), and a conductive metal body is filled in each of the holes to form voltage detection electrodes (210, 220, 230). Unlike a conventional conductive ring, the voltage detection electrodes (210, 220, 230) of this structure are not installed on the inner surface of the opening (120), making installation easy. In addition, since the voltage detection electrodes (210, 220, 230) are filled in the arc-shaped holes (for example, like a conductor filled in a via hole), a sufficient opposing surface area is secured with respect to the core of the transmission line (150), enabling stable voltage measurement, and at the same time, the electrodes are not worn out by contact with the transmission line (150) and have the advantage of having almost no change in detection characteristics over time.

Referring to FIG. 1, a first voltage detection line (212) extending from a first voltage detection electrode (210), a second voltage detection line (222) extending from a second voltage detection electrode (220), and a third voltage detection line (232) extending from a third voltage detection electrode (230) are each independently connected to a sensing circuit unit (130).

By selectively connecting the first voltage detection line (212), the second voltage detection line (222), and the third voltage detection line (232) to the sensor input terminals using physical connectors within the sensing circuit (130), the area of the electrode facing the core of the transmission line (150) can be determined. In addition, as described below, the area of the electrode facing the core of the transmission line (150) can also be determined by switching the voltage scale switches (S1, S2, S3) in the equivalent circuit diagram of FIG. 6. At this time, when the first voltage detection electrode (210), the second voltage detection electrode (220), and the third voltage detection electrode (230) are formed in an arc shape of different lengths, the connection of the voltage detection lines (212, 222, 232) can have the advantage of being able to set the area facing the core of the transmission line (150) in various ways.

Next, the components of the current detection unit are described.

A plurality of via holes (120) are formed on two or more concentric circles formed radially outwardly with different radii centered on an opening of a detection substrate (100). A plurality of current detection coils (310, 320, 330, 340) are formed by winding a conductor through the via holes (120) in a first direction in different regions dividing the detection substrate (100). Then, in a region between regions where the current detection coils (310, 320, 330, 340) are formed, a conductor is wound through the via holes (120) in a second direction opposite to the first direction to form at least one current cancellation coil (360, 370, 380).

As an example, as shown in FIG. 1, the current detection coil may be configured with four coils installed in each of the four quadrants of the detection substrate (100) centered on the opening (110). A first current detection coil (310) is installed in a first region located in the lower left quadrant of the detection substrate (100). In addition, a second current detection coil (320) is installed in a second region of the upper left quadrant of the detection substrate (100), a third current detection coil (330) is installed in a third region of the upper right quadrant, and a fourth current detection coil (340) is installed in a fourth region of the lower right quadrant.

In this case, the current canceling coil is composed of three current canceling coils (360, 370, 380) installed between the current detection coils (310, 320, 330, 340). The first current canceling coil (360) is installed between the first region and the second region, the second current canceling coil (370) is installed between the second region and the third region, and the third current canceling coil (380) is installed between the third region and the fourth region.

When both the current detection coils (310, 320, 330, 340) and the current compensation coils (360, 370, 380) are connected in series, the entire coil has a toroidal shape in which at least a portion is embedded inside the detection substrate (100). At this time, the number of turns of the current compensation coils (360, 370, 380) is installed smaller than the number of turns of the current detection coils (310, 320, 330, 340), and the ratio of the number of turns is approximately 2:1 to 10:1. And since the current canceling coils (360, 370, 380) are wound in the opposite direction to the current detection coils (310, 320, 330, 340), the composite inductance when all coils are connected in series will be greatly reduced compared to the composite inductance when only the current detection coils (310, 320, 330, 340) are connected to each other.

Referring to Fig. 1, current detection electrodes formed at each end of current detection coils (310, 320, 330, 340) and current offset electrodes formed at each end of current offset coils (360, 370, 380) can be printed on the upper surface of the detection substrate (100). In addition, by connecting the current detection electrodes and the current offset electrodes in combination, the composite inductance of the entire coil can be controlled.

To explain more specifically, one end of the first current detection coil (310) is connected to a current detection terminal in the sensing circuit unit (130) as shown in the equivalent circuit diagrams of FIGS. 3, 5, and 6. A first current detection electrode (314) formed at the other end of the first current detection coil (310) and a second current detection electrode (322) formed at one end of the second current detection coil (320) are disposed adjacent to each other. Similarly, a second current detection electrode (324) formed at the other end of the second current detection coil (310) and a third current detection electrode (332) formed at one end of the third current detection coil (330) are disposed adjacent to each other. A third current detection electrode (334) formed at the other end of the third current detection coil (330) and a fourth current detection electrode (342) formed at one end of the fourth current detection coil (340) are disposed adjacent to each other. And the other end of the fourth current detection electrode (340) is connected to a ground terminal in the sensing circuit (130).

Meanwhile, the current canceling electrodes connected to each of the two ends of the current canceling coils (360, 370, 380) are all positioned in a floating state. The first current canceling electrodes (362, 364) at both ends of the first current canceling coil (360) are respectively positioned adjacent to the first current detection electrode (314) and the second current detection electrode (322). The second current canceling electrodes (372, 374) at both ends of the second current canceling coil (370) are respectively positioned adjacent to the second current detection electrode (324) and the third current detection electrode (332). The third current canceling electrodes (382, 384) at both ends of the third current canceling coil (380) are respectively positioned adjacent to the third current detection electrode (334) and the fourth current detection electrode (342).

FIG. 2 is a diagram showing an example of configuring an RF voltage current sensor in a maximum current measurement mode, FIG. 3 is an equivalent circuit diagram showing an example of configuring an RF voltage current sensor in a maximum current and maximum voltage measurement mode, FIG. 4 is a diagram showing an example of configuring an RF voltage current sensor in a minimum current measurement mode, FIG. 5 is an equivalent circuit diagram showing an example of configuring an RF voltage current sensor in a maximum current and minimum voltage measurement mode, and FIG. 6 is an equivalent circuit diagram showing an example of switching control of voltage and current measurement scales. Referring to FIGS. 2 to 6, the process of changing voltage and current measurement scales in the present invention is described as follows.

Referring to FIG. 2, the RF voltage current sensor of the present invention may further include cross-connecting portions (391, 392, 393) that connect adjacently arranged current detection electrodes to each other. The cross-connecting portions (391, 392, 393) may be provided in the form of connectors that solder each electrode or are fitted to each electrode.

Referring to Fig. 2, the first cross-connection portion (391) connects the first current detection electrode (314) and the second current detection electrode (322). Accordingly, as in the equivalent circuit diagram of Fig. 3, the first current detection coil (L1, 310) and the second current detection coil (L2, 320) are directly connected. The second cross-connection portion (392) connects the second current detection electrode (324) and the third current detection electrode (332). As in the equivalent circuit diagram of Fig. 3, the second current detection coil (L2, 320) and the third current detection coil (L3, 330) are directly connected. The third cross-connection portion (393) connects the third current detection electrode (334) and the fourth current detection electrode (342). As in the equivalent circuit diagram of Fig. 3, the third current detection coil (L3, 330) and the fourth current detection coil (L4, 340) are directly connected. Referring to Figs. 2 and 3, the first current cancellation coil (L5, 360), the second current cancellation coil (L6, 370), and the third current cancellation coil (L7, 380) are all in a floating state and do not affect the inductance of the entire circuit.

That is, as in the equivalent circuit diagram of Fig. 3, only the first to fourth current detection coils (L1 to L4) wound in the same direction are connected in series, so the current detection unit has the maximum synthetic inductance and the measurement current scale is at the maximum.

In addition, as illustrated in FIG. 3, when all three voltage detection electrodes (210, 220, 230) are connected to the voltage detection terminal of the sensing circuit (130), the voltage detection unit has the largest surface area facing the core of the transmission line (150), and thus has the highest capacitance according to the formula for calculating capacitance. Accordingly, the measurement voltage scale of the voltage detection unit is also at its maximum.

Referring to FIG. 4, the RF voltage current sensor of the present invention may further include bypass connectors (394, 395, 396, 397, 398, 399) that connect adjacently arranged current detection electrodes and current compensation electrodes to each other. The bypass connectors (394, 395, 396, 397, 398, 399) may be provided in the form of connectors that solder each electrode or are fitted to each electrode.

Referring to FIG. 4, the first bypass connection (394) connects the first current detection electrode (314) and the first current canceling electrode (362), and the second bypass connection (395) connects the second current detection electrode (322) and the first current canceling electrode (364). Accordingly, as in the equivalent circuit diagram of FIG. 5, the first current detection coil (L1, 310) and the second current detection coil (L2, 320) are connected via the first current canceling coil (L5, 360). The third bypass connection (396) connects the second current detection electrode (324) and the second current canceling electrode (372), and the fourth bypass connection (397) connects the third current detection electrode (332) and the second current canceling electrode (374). As in the equivalent circuit diagram of Fig. 5, the second current detection coil (L2, 320) and the third current detection coil (L3, 330) are connected via the second current cancellation coil (L6, 370). The fifth bypass connection (398) connects the third current detection electrode (334) and the third current cancellation electrode (382), and the sixth bypass connection (399) connects the fourth current detection electrode (342) and the third current cancellation electrode (384). As in the equivalent circuit diagram of Fig. 5, the third current detection coil (L3, 330) and the fourth current detection coil (L4, 340) are connected via the third current cancellation coil (L7, 380).

Referring to FIGS. 4 and 5, all coils (L1 to L7) are connected in series, and the current canceling coils (L5 to L7) wound in the opposite direction to the current detection coils (L1 to L4) cancel out the inductance, so that the current detection unit has the minimum synthetic inductance and the measurement current scale is at the minimum.

In addition, as shown in FIG. 5, when only the second voltage detection electrode (220) among the three voltage detection electrodes (210, 220, 230) is connected to the voltage detection terminal of the sensing circuit (130), and when the second voltage detection electrode (220) has the smallest opposing area with respect to the core of the transmission line (150), the voltage detection unit has the lowest electrostatic capacitance with respect to the core of the transmission line (150). Therefore, the measurement voltage scale of the voltage detection unit is also at its minimum.

Referring to Fig. 6, the voltage detection unit controlling the area facing the core of the transmission line (150) and the current detection unit controlling the synthetic inductance for the induced current can both be implemented as switches switched by an electrical signal.

The sensing circuit unit (130) may include a first voltage scale switch (S1, 410) that switches the connection between the voltage detection terminal and the first voltage detection electrode (210), a second voltage scale switch (S2, 420) that switches the connection between the voltage detection terminal and the second voltage detection electrode (220), and a third voltage scale switch (S3, 430) that switches the connection between the voltage detection terminal and the third voltage detection electrode (230). By controlling the switching of the first voltage scale switch to the third voltage scale switch (S1 to S3) by an unillustrated controller, scaling of the measured voltage can be easily performed.

Additionally, the sensing circuit (130) may further include current scale switches (S4 to S9) that switch between directly connecting adjacent current detection coils or connecting them by bypassing the current compensation coil.

The first current scale switch (S4, 440) may be configured as a three-way switch in which the other end of the first current detection coil (L1, 310) is selectively connected to one end of the second current detection coil (L2, 320) or one end of the first current canceling coil (L5, 360). The second current scale switch (S5, 450) may be configured as a three-way switch in which one end of the second current detection coil (L2, 320) is selectively connected to the other end of the first current detection coil (L1, 310) or the other end of the first current canceling coil (L5, 360). The third current scale switch (S6, 460) may be configured as a three-way switch in which the other end of the second current detection coil (L2, 320) is selectively connected to one end of the third current detection coil (L3, 330) or one end of the second current canceling coil (L6, 370). The fourth current scale switch (S7, 470) may be configured as a three-way switch in which one end of the third current detection coil (L3, 330) is selectively connected to the other end of the second current detection coil (L2, 320) or the other end of the second current canceling coil (L6, 370). The fifth current scale switch (S8, 480) may be configured as a three-way switch in which the other end of the third current detection coil (L3, 330) is selectively connected to one end of the fourth current detection coil (L4, 340) or one end of the third current canceling coil (L7, 380). The sixth current scale switch (S9, 490) may be configured as a three-way switch in which one end of the fourth current detection coil (L4, 340) is selectively connected to the other end of the third current detection coil (L3, 330) or the other end of the third current canceling coil (L7, 380).

By controlling the switching of the current scale switches (S4 to S9) by the controller not shown in the figure, the scaling of the measured current can be easily performed by selecting a combination of cross-connecting the current detection coils or connecting them by bypassing the current compensation coils, thereby adjusting the synthetic inductance.

The invention disclosed above is capable of various modifications without detracting from the fundamental concept. In other words, the above embodiments should be interpreted as illustrative and not limiting. Therefore, the scope of protection of the present invention should be determined by the appended claims, not the aforementioned embodiments. Any replacement of elements defined in the appended claims with equivalents should be deemed within the scope of protection of the present invention.

100: Detection substrate 110: Aperture
120: Via hole 130: Sensing circuit
132, 134: Sensor output port 150: Transmission line
210: First voltage detection electrode 212: First voltage detection line
220: Second voltage detection electrode 222: Second voltage detection line
230: Third voltage detection electrode 232: Third voltage detection line
310: First current detection coil 314: First current detection electrode
320: Second current detection coil 322, 324: Second current detection electrode
330: Third current detection coil 332, 334: Third current detection electrode
340: 4th current detection coil 342: 4th current detection electrode
360: First current canceling coil 362, 364: First current canceling electrode
370: Second current canceling coil 372, 374: Second current canceling electrode
380: Third current canceling coil 382, 384: Third current canceling electrode
391: First cross connection 392: Second cross connection
393: Third cross connection 394: First bypass connection
395: Second bypass connection 396: Third bypass connection
397: 4th bypass connection 398: 5th bypass connection
399: 6th bypass connection 410: 1st voltage scale switch
420: Second voltage scale switch 430: Third voltage scale switch
440: First current scale switch 450: Second current scale switch
460: 3rd current scale switch 470: 4th current scale switch
480: 5th current scale switch 490: 6th current scale switch

Claims (5)

A detection substrate having a circular opening through which a transmission line transmitting an RF (Radio Frequency) signal passes;
A plurality of voltage detection electrodes, each of which is installed on the detection substrate along the perimeter of the opening and has an arc-shaped conductor that is capacitively coupled to the core of the transmission line and is spaced apart from each other with a predetermined gap;
A plurality of via holes formed on a plurality of concentric circles formed radially outwardly with different radii centered on the opening of the above detection substrate;
A plurality of current detection coils each comprising a conductor wound through the plurality of via holes, forming a secondary coil inductively coupled with the core of the transmission line, and comprising a plurality of conductors wound through the via holes in different regions;
At least one current canceling coil composed of a conductor wound through the via holes in the opposite direction to the current detecting coil between the current detecting coils; and
A sensing circuit installed on the detection substrate, converting a voltage applied between at least one of the plurality of voltage detection electrodes and the ground side into a predetermined voltage level and outputting it, converting a current induced in the current detection coil into a predetermined current level and outputting it, and adjusting the scale of the measured current by selecting the connection between the current detection coil and the current offset coil.
RF voltage current sensor including.
In the first paragraph,
An RF voltage current sensor in which a plurality of arc-shaped holes are formed around the opening of the detection substrate and spaced apart from the opening, and a conductive metal body is filled in each of the holes to form the voltage detection electrode.
In the first paragraph,
An RF voltage current sensor wherein each of the above voltage detection electrodes has an arc shape of different length.
In any one of the first to third paragraphs,
An RF voltage current sensor, wherein the sensing circuit unit further includes a plurality of voltage scale switches individually installed between each of the voltage detection electrodes and the voltage detection terminal to switch the connection between the voltage detection electrodes and the voltage detection terminal.
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