JP7016238B2 - Directional coupler - Google Patents

Description

The present invention relates to a directional coupler that detects a traveling wave and a reflected wave.

With the recent advancement of processing technology in semiconductor manufacturing equipment, high-precision measurement and precise control of high-frequency power in plasma processes are required.

As a method for measuring high-frequency power passing over a transmission line, as represented by Japanese Patent No. 3,299,273, two high-frequency signals are detected and processed by using an electromagnetic field generated in the transmission line. The method of doing is the mainstream.

Electromagnetic field sensors are roughly classified into two types according to the characteristics of the detected signals, and are called directional couplers and V / I sensors. The directional coupler pays attention to the electromagnetic wave traveling in the propagation direction existing in the transmission line and the electromagnetic wave reflected and returned, and detects the traveling wave signal and the reflected wave signal. The V / I sensor detects electric field / magnetic field fluctuations individually and detects them as a voltage signal / current signal or a combined signal thereof. In either method, the detected signal is subjected to addition / subtraction, multiplication / division, phase detection, A / D conversion, digital signal processing, etc., and the progressive wave power, reflected wave power, effective power consumption, and load impedance for each frequency are performed. Is converted to.

One of the important factors in the performance of the directional coupler is that the measured value of effective power consumption does not fluctuate due to environmental factors. However, the material of the member constituting the directional coupler is easily affected by the temperature change, and the detection voltage of the sensor itself fluctuates due to the temperature change.

Resistance and capacitor elements that make up a directional coupler have traditionally had parts with little temperature change, but the degree of coupling of magnetic materials changes due to temperature changes in magnetic permeability and non-linearity caused by the BH curve. Therefore, the magnetic field coupling sensor of the prior art using a magnetic material cannot ignore the fluctuation of the detection voltage due to the temperature change because the detection voltage is changed.

As a countermeasure, sensors with high shape accuracy using photolithography technology, such as microstrip type directional couplers formed on printed wiring boards and current / voltage sensors in which patterns are connected by through holes or blind vias, are used. There is an example of improvement to create.

FIG. 9 is a stripline type directional coupler in which the main line 115a is arranged on the substrate 125a and the sub lines 123a and 123a are arranged on both sides of the main line 115a, and is at one end of the sub lines 123a and 123a. Is connected to the terminal circuit 124, and the current of the traveling wave and the current of the reflected wave flowing through the main line 115a are individually detected by the sub lines 123a and 123a.

FIG. 10 is a printed wiring board via pattern coil type directional coupler in which an auxiliary line 123b is provided on a printed wiring board 116 sandwiched between two housings 111 and 112, and is inserted into a cable hole 136b. The current of the traveling wave and the current of the reflected wave flowing through the inner conductor 115b are separately detected by the auxiliary line 123b. Reference numeral 124b is a terminal circuit.
However, there is a substrate material that becomes a dielectric around the auxiliary lines 123a and 123b, which is one of the causes of deterioration of the characteristics.

FR4, which is generally used as a substrate material, causes dimensional changes and dielectric constant changes depending on water absorption, humidity, and temperature, and causes impedance changes in the sensor circuit of the printed wiring board. In addition, since it is exposed to extremely large temperature changes in high-power applications, it is necessary to use more expensive substrate materials in order to stabilize the measurement results.

An air-core 1-turn coil type current sensor / directional coupler has existed in the past, for example, at low frequencies of around 1 MHz, the sensor shape becomes longer in the propagation direction in order to increase the degree of coupling, and the volume of the sensor increases. growing.

Japanese Patent No. 3299273 U.S. Pat. No. 6,449,568 US Pat. No. 6,501,285 Japanese Patent No. 3317684 Japanese Patent No. 5599607 U.S. Pat. No. 8,414,326 Japanese Unexamined Patent Publication No. 11-8095 Japanese Unexamined Patent Publication No. 8-335809 Japanese Unexamined Patent Publication No. 2000-49510 Japanese Patent Application Laid-Open No. 2003-32013 Japanese Unexamined Patent Publication No. 2006-191221 Japanese Unexamined Patent Publication No. 2009-105863 U.S. Pat. No. 7,755,451 U.S. Pat. No. 8,203,398 U.S. Pat. No. 7,885,774

The present invention is to provide a technique in which the detection accuracy does not decrease even if the temperature changes, and provides a compact directional coupler in which the detection level and the detection phase are stable at a relatively low cost.

In order to solve the above problems, the present invention provides a printed wiring board, a cable hole formed in the printed wiring board through which a conductive wire to be measured is inserted, and a cable hole provided in the printed wiring board. A directional coupler having a first detection unit for detecting one of a traveling wave and a reflected wave flowing through the conductive wire inserted through the wire, and a second detection unit for detecting the other. The first and second detectors have a plurality of curved detectors in which a measuring hole is located in the center, and a plurality of internal wirings connecting the detectors to the detectors. One end of the above is arranged near the edge of the measuring hole, the other end is arranged farther from the edge than the one end, and the detectors are placed on the printed wiring board. The first and second detectors, which are erected facing each other, have windings formed by the plurality of detectors and the plurality of internal wirings, and the first detector thereof. The measuring hole of the detector forming the winding and the measuring hole of the detector forming the winding of the second detection unit have a current in the conductive wire inserted through the cable hole. It is a directional coupler arranged so that at least a part of the magnetic flux formed when the current flows through.
The present invention is a directional coupler in which the internal wiring is a metal film formed on the printed wiring board.
In the present invention, when either the clockwise direction or the counterclockwise direction about the center of the cable hole is set as the first arrangement direction, the first detection unit is near the edge. The end portion arranged in the first having the detector connected to the end portion arranged far from the edge of the detector arranged adjacent to the first arrangement direction. When the direction same as or opposite to the arrangement direction is set as the second arrangement direction, in the second detection unit, the end portion arranged near the edge is arranged adjacent to the second arrangement direction. A directional coupler having the detector connected to the end located far from the edge of the detector.
In the present invention, the detector of the first detection unit and the detector of the second detection unit are directional couplers arranged on the same surface of the printed wiring board.
In the present invention, the detector of the first detection unit and the detector of the second detection unit are directional couplers arranged on different surfaces of the printed wiring board.
The present invention is a directional coupler having the conductive wire inserted through the cable hole.
The present invention is a directional coupler in which an internal conductor of a coaxial cable is used for the conductive wire.

Detection results that are not affected by temperature can be obtained.

The figure which shows the appearance of the direction detector of one example of this invention. The figure which shows the detector body of this invention (a), (b): The figure which shows the detector of this invention. (a): A diagram for explaining a connecting electrode portion (b): A diagram for explaining an upright detector. The figure which shows the appearance of the direction detector of another example of this invention. Cross section of the direction detector Graph showing the relationship between temperature and gain fluctuation Graph showing the relationship between temperature and phase fluctuation Conventional stripline directional coupler Conventional Printed Wiring Board Via Pattern Coil Type Directional Coupler

With reference to FIGS. 1 and 2, reference numeral 10a is a directional coupler according to the first example of the present invention, which includes a first housing 11, a second housing 12, and a detector body 16. ..
The detector main body 16 has a printed wiring board 25, and a cable hole 36 penetrating the printed wiring board 25 is provided at the center position of the printed wiring board 25. Reference numeral 29 is a hole for attaching the directional coupler 10a. The printed wiring board 25 of FIG. 1 corresponds to a cross-sectional view taken along the line AA of the printed wiring board 25 of FIG.

The measurement target of the directional coupler 10a is, for example, a coaxial cable for supplying power to a device using a high frequency voltage, and the coaxial cable generally has a tubular outer conductor connected to a ground potential and an outer conductor. Has a thick wire-shaped inner conductor inserted inside the outer conductor in an insulated state.

Reference numeral 15 in FIG. 1 is a conductive wire to be measured by the directional coupler 10a of the present invention, in which the internal conductor of the coaxial cable is inserted into the cable hole 36 as the conductive wire 15. The conductive wire is not limited to the internal conductor of the coaxial cable, and for example, a signal wire among two parallel electric wires can be used as the conductive wire.

The detection unit 20 is arranged on the printed wiring board 25 located around the cable hole 36.
The detection unit 20 has a first detection unit 21a for detecting one of the reflected wave currents flowing in the direction opposite to the traveling wave current flowing in the conductive wire 15 in one direction, and the detection unit 20 for detecting the other current. A second detection unit 22a is provided. The first and second detection units 21a and 22a have a plurality of connecting electrode units 40 shown in FIG. 4 and a plurality of detectors 23a, respectively.

Each detector 23a has the same shape, and FIG. 3A is an example of the shape of the detector 23a. The detector 23a is a component that constitutes one turn in the winding described later, and one detector 23a is a piece of metal having a curved shape so that both ends are located close to each other and separated from each other. It is a plate, and the shape of the metal plate is U-shaped.

A measurement hole 31 surrounded by a metal plate of the detector 23a is formed in the center of each detector 23a. When the curved metal plate portion in the detector 23a is referred to as a loop portion 32, connection portions 33 facing the outside of the loop portion 32 are provided at one end and the other end of the loop portion 32, respectively. There is. Here, the connecting portion 33 is formed by bending the vicinity of one end and the vicinity of the other end of the loop portion 32.

The plurality of connecting electrode portions 40 included in the first detection unit 21a and the plurality of connecting electrode portions 40 included in the second detection unit 22a are arranged along the edge 39 of the cable hole 36.
As shown in FIG. 4A, the connecting electrode portion 40 has an inner electrode 41, an outer electrode 42, and an inner wiring 43, and the inner electrode 41 is arranged near the edge 39, and the outer electrode 42 is arranged. Is located farther from the edge 39 than the inner electrode 41, and one inner electrode 41 and one outer electrode 42 are connected by one internal wiring 43.

Assuming that one of the clockwise and counterclockwise directions centered on the center of the cable hole 36 is the arrangement direction, the outer electrode 42 of one connecting electrode portion 40 is in the arrangement direction with respect to the inner electrode 41. The inner electrodes 41 of one connecting electrode portion 40 are separated from each other, and are arranged between the outer electrodes 42 of the connecting electrode portions 40 adjacent to each other in the direction opposite to the arrangement direction and the edge 39. The arrangement direction of the first detection unit 21a and the arrangement direction of the second detection unit 22a may be the same direction or opposite to each other.

The cable hole 36 is circular, and the inner electrode 41 and the outer electrode 42 are arranged on a circle centered on the center of the cable hole 36, and are arranged in the arrangement direction with the outer electrode 42 of one connecting electrode portion 40. The inner electrode 41 of the adjacent connecting electrode portion 40 is located on the same radiation 44 passing through the center of the cable hole 36.

The first connection electrode 46 is arranged outside the inner electrode 41 of the connecting electrode portion 40 which is the starting point in the arrangement direction, while the outer electrode 42 of the connecting electrode portion 40 which is the ending point in the arrangement direction. A second connection electrode 47 is arranged inside. Therefore, the inner electrode 41 of the connecting electrode portion 40 which is the starting point in the arrangement direction and the first connecting electrode 46 are located on the same radiation 44, and the outer electrode 42 of the connecting electrode portion 40 which is the ending point in the arrangement direction. The second connection electrode 47 is located on the same radiation 44.
The first external wiring 27 is connected to the first connection electrode 46, and the second external wiring 28 is connected to the second connection electrode 47.

The inner electrode 41, the outer electrode 42, the inner wiring 43, and the first and second external wirings 27 and 28 are formed of a metal film of several μm to several hundred μm and are in close contact with the printed wiring board 25. It is fixed, and the parasitic-inducing component formed between the inner electrode 41 and the outer electrode 42 is made smaller.
Further, the inner electrode 41 and the outer electrode 42 are arranged apart from each other so that the parasitic capacitance component is also reduced.

Each detector 23a is perpendicular to the printed wiring plate 25, and the inner electrode 41 and the first connection electrode 46 arranged on the same radiation 44 have two connection portions 33 of one detector 23a. One each is connected and fixed, and the second connection electrode 47 and the outer electrode 42 arranged on the same radiation 44 have two connection portions 33 of another detector 23a. One each is connected and fixed, and the inner electrode 41 and the outer electrode 42 arranged on the same radiation 44 have one each of two connecting portions 33 of another detector 23a. It is connected and fixed.

In this state, the detector 23a included in the first detection unit 21a faces the measurement holes 31 of the adjacent detectors 23a so that the measurement holes 31 communicate with each other on the same surface of the printed wiring board 25. The detector 23a of the second detector 22a, which is erected, also faces the same surface of the printed wiring board 25 so that the measurement holes 31 of the adjacent detectors 23a face each other and the measurement holes 31 communicate with each other. Each detector 23a is erected on the printed wiring board 25 and fixed to the printed wiring board 25.

Assuming that the portion connected to the inner electrode 41 of each detector 23a is the inner end and the portion connected to the outer electrode 42 is the outer end, the inner end of the detector 23a is provided by the internal wiring 43 provided on the printed wiring board 25. Is connected to the outer end of the adjacent detector 23a, and since the loop portion 32 of each detector 23a is erected on the printed wiring board 25, the detector 23a and the internal wiring 43 wind in the same direction. A turned spiral winding is formed.

Each detector 23a is arranged so that the measuring holes 31 of the detectors 23a constituting the same winding are communicated with each other, and the air core of the winding is formed by the communicating measuring holes 31. When a current flows through a conductive wire 15 made of an internal conductor inserted into a cable hole 36 and a circular magnetic flux centered on the conductive wire 15 is formed, a part of the magnetic flux forms a measurement hole 31 constituting an air core. An electromotive force is generated in each detector 23a having a measuring hole 31 that penetrates and the magnetic flux penetrates.

Each detector 23a of the same winding is connected in series so that the electromotive force generated in each detector 23a is added without canceling each other, and the total electromotive force of each amplified detector 23a is totaled. Power appears between the first connection electrode 46 and the second connection electrode 47.

The first and second external wirings 27 and 28 are extended on the printed wiring board 25, one external wiring is connected to the voltage output terminal, and the other external wiring is connected to the ground potential via the termination circuit 24. ing. The first external wiring 27 is connected to the voltage terminal, the second external wiring 28 is connected to the ground potential via the termination circuit 24, and the first, depending on the configuration of the internal circuit of the connected termination circuit 24, One of the second detection units 21a and 22a detects the traveling wave flowing through the conductive wire 15, and the other detects the reflected wave flowing through the conductive wire 15, a signal indicating the magnitude of the traveling wave and the magnitude of the reflected wave. The signal indicating that can be taken out from a separate voltage terminal. When the voltage of the voltage terminal is taken out by a detection device such as an analog IC or an operating amplifier connected to the voltage terminal, the size of the traveling wave or the reflected wave is obtained, and the obtained size can be displayed on a display or the like. ..
Since the detector 23a is made of a rigid metal plate, the electrical characteristics do not change due to deformation.

In the prior art, a winding can be formed by the metal wiring formed on the front surface and the back surface of the printed wiring board and the metal filling filled in the through hole, but the core of the winding constitutes the printed wiring board. It becomes a resin. Since the dielectric constant of the resin fluctuates greatly depending on the temperature, the electrical characteristics of the winding centered on the printed wiring board fluctuate greatly depending on the temperature.
In the directional coupler 10a of the present invention, since the core of the winding composed of the detector 23a and the internal wiring 43 is air, the electrical characteristics of the winding are not affected by the temperature change.

FIG. 7 is a graph showing the relationship between the temperature and the detection signal gain fluctuation when the normal temperature is used as a reference, and FIG. 8 shows the relationship between the temperature and the detection signal phase fluctuation when the normal temperature is used as a reference. It is a graph.

From FIGS. 7 and 8, the characteristics of the directional coupler of the prior art have a large influence on the temperature with respect to the fluctuation of the detection signal gain and the fluctuation of the detection signal phase, whereas the characteristics of the directional coupler of the present invention are due to the temperature change. It can be said that there is no effect.

In the directional coupler 10a described above, the first detection unit 21a and the second detection unit 22a are arranged on the same surface of the printed wiring board 25, but the first detection unit 21a and the second detection unit 21a are arranged on the same surface. The portion 22a and the portion 22a may be arranged on different surfaces of the printed wiring board 25.

For example, in the directional coupler 10b of FIGS. 5 and 6, the detector 23a of the first detection unit 21b is placed on one side of the printed wiring board 25 sandwiched between the first housing 11 and the second housing 12. A connecting electrode portion for connecting the detectors 23a to each other is arranged, and the detector 23a of the second detector 22b is arranged on the surface opposite to the surface on which the detector 23a of the first detector 21b is arranged. , A connecting electrode portion for connecting the detectors 23a to each other is arranged.

When arranged in this way, the number of detectors 23a provided in the first and second detectors 21b and 22b is increased as compared with the case where the first and second detectors 21a and 22a are arranged on the same surface. Therefore, the detection sensitivity is improved.

The arrangement direction of the connecting electrode unit 40 in FIG. 4 was a clockwise direction, but depending on the contents of the terminal circuit 24, the arrangement direction of the first detection unit 21a and the arrangement direction of the second detection unit 22a may be different. They may be in the same direction or in opposite directions.

Further, in the detector 23a, the connection portion 33 is facing outward, but as shown in FIG. 3B, a detector 23b in which the connecting portions 34 facing inward are provided at both ends of the loop portion 32 is used. You can also. The detectors 23a and 23b can form windings by bending a metal plate having a thickness of 0.1 mm or more and a width of 0.3 mm or more. Further, a conductor other than metal can also be used.

The directional coupler of the present invention may be provided with a conductive wire, and the conductive wire 15 is inserted through the cable hole 36 so that the internal conductor or the like to be measured can be the conductive wire 15. You may not let it.

An RF power supply device that controls the magnitude of the output voltage by converting the traveling wave / reflected wave measured by the built-in directional coupler of the present invention into a DC voltage can be obtained.
An RF power supply device that calculates the active power and impedance from the traveling wave / reflected wave measured by the built-in directional coupler of the present invention and changes the frequency and the magnitude of the traveling wave so as to obtain a predetermined active power can be obtained. ..

A matching box can be obtained in which the reflection coefficient is obtained from the traveling wave / reflected wave measured by the built-in directional coupler of the present invention and the variable reactance is controlled to make the reflection coefficient zero.

10a, 10b ... Directional coupler 15 ... Conductive wire 21a, 21b ... First detection unit 22a, 22b ... Second detection unit 23a, 23b ... Detector 25 ... Printed wiring board 36 ... Cable hole 41 …… Inner electrode 42 …… Outer electrode 43 …… Internal wiring

Claims (6)

Printed wiring board and
A cable hole formed in the printed wiring board through which the conductive wire to be measured is inserted, and
A first detection unit provided on the printed wiring board to detect either a traveling wave or a reflected wave flowing through the conductive wire inserted through the cable hole, and a second detection unit to detect the other are provided. It is a directional coupler that has
The first and second detectors are a plurality of detectors erected on one surface of the printed wiring board and having a curved shape in which a measurement hole is located in the center, and the plurality of detectors formed on the one surface. Each of the detectors has an internal wiring that connects between adjacent detectors.
Of both ends of each of the plurality of detectors, one end is located near the edge of the cable hole and the other end is located farther from the edge than the one end. The measuring holes of the detectors of the above are erected facing each other on one of the above surfaces .
The first and second detectors form windings arranged on the printed wiring board by the plurality of detectors and the internal wiring.
Each measurement hole of the plurality of detectors forming the winding of the first detection unit and each measurement hole of the plurality of detectors forming the winding of the second detection unit are the cables. A directional coupler that forms an air core through which at least a part of the magnetic flux formed when a current flows through the conductive wire inserted through the hole. The directional coupler according to claim 1 , wherein the internal wiring is a metal film formed on one of the surfaces . Printed wiring board and
A cable hole formed in the printed wiring board through which the conductive wire to be measured is inserted, and
A first detection unit provided on the printed wiring board to detect either a traveling wave or a reflected wave flowing through the conductive wire inserted through the cable hole, and a second detection unit to detect the other are provided. It is a directional coupler that has
The first detector includes a plurality of detectors erected on one surface of the printed wiring board and having a curved shape in which a measurement hole is located in the center, and the plurality of detectors formed on the one surface. Of which has internal wiring to connect between adjacent detectors,
The second detector includes a plurality of detectors erected on the other surface of the printed wiring board and having a curved shape in which a measurement hole is located in the center, and the plurality of detectors formed on the other surface. Of which has internal wiring to connect between adjacent detectors,
Of both ends of each of the plurality of detectors constituting the first detector, one end is arranged near the edge of the cable hole, and the other end is more than the one end. Arranged far from the edge, the measurement holes of the plurality of detectors are erected facing each other on one of the surfaces.
Of both ends of each of the plurality of detectors constituting the second detector, one end is arranged near the edge of the cable hole, and the other end is more than the one end. Arranged far from the edge, the measuring holes of the plurality of detectors are erected facing each other on the other surface.
The first and second detectors form windings arranged on the printed wiring board by the plurality of detectors and the internal wiring.
Each measurement hole of the plurality of detectors forming the winding of the first detection unit and each measurement hole of the plurality of detectors forming the winding of the second detection unit are the cables. A directional coupler that forms an air core through which at least a part of the magnetic flux formed when a current flows through the conductive wire inserted through the hole. Of the plurality of detectors constituting the first detection unit, when either the clockwise direction or the counterclockwise direction centered on the center of the cable hole is set as the first arrangement direction. , The one end of one detector is connected to the other end of another detector placed adjacent to the first placement direction, in the same direction as or in the opposite direction of the first placement direction. When the direction is set to the second arrangement direction , the one end of one of the plurality of detectors constituting the second detection unit is arranged adjacent to the second arrangement direction. The directional coupler according to any one of claims 1 to 3 , which is connected to the other end of the other detector. The directional coupler according to any one of claims 1 to 4 , which has the conductive wire inserted through the cable hole. The directional coupler according to claim 5 , wherein an internal conductor of a coaxial cable is used for the conductive wire.

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