JP2003114265A - High frequency circuit and shielded loop field detector using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a highly reliable field measurement by intensifying the shielding performance of a strip line and suppressing electromagnetic interference. SOLUTION: A lead portion 605 formed on the strip line 601 of a triplate formed on a multilayer circuit board consists of an internal conductor 602, two finite-width glands 603 sandwiching the internal conductor 602, via holes 608 for short-circuiting the two glands 603 at either ends in the cross direction. The plurality of via holes 608 are provided in the longitudinal direction as the transfer direction of the strip line, and the cross section of the strip line is shaped such that one internal conductor is encircled by the two glands sandwiching it and the via holes on both sides, thereby suppressing the electromagnetic interference with surroundings. An output generated by a magnetic filed interlinking a loop opening portion 610 of a field detecting loop portion 606 is propagated as a strip line mode to the left end via the lead portion 605.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency circuit including a strip line, and more particularly to a structure for enhancing the shield performance of the strip line to suppress the influence of ambient electromagnetic noise and electromagnetic interference such as crosstalk, and The present invention relates to a magnetic field detector using the strip line structure.

[0002]

2. Description of the Related Art In a high frequency circuit, electromagnetic wave interference may occur between a plurality of circuit elements and transmission lines connecting the circuit elements, which may lead to deterioration of circuit characteristics. For circuits that easily radiate electromagnetic waves and circuits that are easily affected by external electromagnetic waves, various measures have been taken, such as electromagnetic shielding using a metal case or a metal pattern of a printed circuit board.

Further, in order to enhance the shielding property of the transmission line, the microstrip line in which the metal strip is exposed in the surface layer is changed to a triplate strip line in which the metal strip is sandwiched between the upper and lower ground layers. Sometimes. This change to the triplate strip line can suppress at least the effects of direct electromagnetic radiation and external electromagnetic waves from the mounted circuit element, and contribute to suppressing the characteristic deterioration of the entire circuit.

However, the shield performance of the triplate strip line and the 雖 is not perfect, and there is a problem such as crosstalk between adjacent strip lines formed in the same layer. In that case, as shown in FIG. Vias 2003 are provided above and below the ground 2002 on both sides of the inner conductor 2001 so as to surround the inner conductor 2001 as shown.
In some cases, a countermeasure is taken such as electrically connecting with each other and providing a plurality of vias in the transmission path direction to enhance the isolation from the adjacent strip line.

The triplate strip line is more disadvantageous than the microstrip line in mounting circuit elements, but when the circuit elements are separated from each other and a relatively long distance is required to be connected, the triplate strip line has this shielding property. It is useful to apply high triplate strip line. Therefore, it is useful to use the microstrip line in the vicinity of the mounted circuit and the triplate strip line in the case of a relatively long inter-circuit connection.

When a high frequency circuit module composed of one multi-layer circuit board or the like is connected to a high frequency circuit module composed of another multi-layer circuit board or the like which is separated from each other, between the transmission and reception terminals of each other. A transmission line having a high shielding property such as a coaxial line is often used.

FIG. 12 shows the simplest method of connecting the coaxial line to the aforementioned strip line formed on the multilayer circuit board.

The inner conductor 21 in the multilayer circuit board 2100
In the triplate strip line 2103 in which 01 is sandwiched between two grounds 2102, the inner conductor 2101 is led to a pad 2106 provided on the uppermost layer 2105 having a certain area through the via 2104, and the pad 21
The center conductor 2108 of the coaxial line 2107 is soldered to
It is electrically connected by means such as 09. In addition, the ground 2102 of the strip line 2103 is connected to the via 21.
The outer conductor 2112 of the coaxial line 2107 is led to the pad 2111 provided on the uppermost layer via the wiring 10 and electrically connected to the pad 2111 by means such as solder 2113.

Also, a patent has been filed for an invention relating to a shielded loop type magnetic field detector constructed by using such a triplate strip line (Japanese Patent Application No. 10-3.
No. 46030). FIG. 13 shows an example of a shielded loop type magnetic field detector using a triplate strip line disclosed in the above patent application specification.

In FIG. 13, an inner conductor 2202 is formed on one unexposed layer of a multilayer circuit board 2201 having at least three layers, and a ground 2203 is formed above and below the inner conductor with an insulator interposed therebetween. And constitutes a triplate strip line 2204. An insulator may be provided on one or both of the upper ground and the lower ground to increase the strength of the substrate.

A straight strip line extending from the left end is a lead portion 2205, and a rectangular portion which is bent at a right angle on the right side is a loop portion 2206. The terminal 2207 of the loop unit 2206 is short-circuited to the ground 2203 of the strip line 2204. Loop part 2206
Has a void 2208 at the right end and forms a square loop opening 2209.

Further, the inner conductor 2202 is provided in the first half-circumferential portion 2210 of the loop portion, and the void 2208 of the ground is provided.
After crossing the second half via the via 2211
It is electrically connected to the end of the ground in 212.

With the above structure, the loop opening 2209
The output generated by the magnetic field that interlinks with each other propagates to the left end of the lead portion 2205 as a stripline mode.

[0014]

As described above, in the triplate-type strip line, since the inner conductor is sandwiched between the upper and lower ground layers, the shield performance is high due to the ground layers in the vertical direction. Since the direction is open, the shield performance is not high, and even when it is used as a strip line that connects circuit elements to each other, the shield is not electromagnetically perfect. Therefore, it has been conventionally considered effective to widen the upper and lower ground layers in order to enhance the shield performance for the inner conductor of the strip line.

Further, as shown in FIG. 11, by connecting vias between the upper and lower grounds so as to surround the inner conductor on both sides of the inner conductor, and increasing the isolation from the adjacent strip line, the same is achieved. It is possible to solve some problems such as crosstalk between adjacent strip lines formed in a layer, but even if there is disturbance of the electromagnetic field near the via, electromagnetic interference occurs between them. There was a problem, and the isolation from the adjacent stripline was not always sufficient.

Further, as shown in FIG. 12, when the strip line and the coaxial line are connected to each other, since the central conductor 2108 of the coaxial line is exposed, the circuit elements and wirings mounted in the vicinity of the central conductor 2108 are exposed. It is easily affected by the electromagnetic field emitted from. Further, when there is a bending of the substrate or a stress on the coaxial line due to an action from the outside, there is a problem that the solder or the metal pattern is peeled off and the electrical connection state is deteriorated.

Further, a PCB is arranged on the right side of the shielded loop type magnetic field detector of the conventional strip line structure as shown in FIG. 13, and the PCB is arranged by this magnetic field detector.
When detecting a magnetic field in the vicinity of a wiring, the electromagnetic field near the PCB, particularly near the PCB in which a large number of circuit elements are mounted and high-density wiring is often not uniform, and is very disturbed. When this magnetic field detector is placed in an electromagnetic field, it is difficult to detect only the target magnetic field, no matter how much the shielded loop structure is.

Further, since the inner conductor of the strip line has a ground in the vertical direction, the shield performance is high, but in the lateral direction, the shield performance is low because it is open. P there
When a disturbed electromagnetic field such as the vicinity of CB exists, an unnecessary electromagnetic field other than the target magnetic field is detected, and there is a problem that the measurement accuracy deteriorates.

An object of the present invention is to enhance the shielding performance of the strip line in a high frequency circuit including the strip line, and suppress the influence of ambient electromagnetic noise and electromagnetic interference such as crosstalk.

Another object of the present invention is to construct a shielded loop type magnetic field detector using the strip line having the enhanced shield performance.

[0021]

The high frequency circuit of the present invention comprises:
The triplate strip line formed on the multilayer circuit board makes the pattern width of the two grounds that sandwich the inner conductor a finite width wider than the pattern width of the inner conductor, and also connects the two grounds at both ends in the width direction of the ground. Short-circuited via vias, etc., and multiple vias are provided in the longitudinal direction that is the transmission direction of the strip line. Therefore, in a cross section including vias, one inner conductor is surrounded by two grounds sandwiching it and vias on both sides. It is characterized by being.

As a result, adjacent strip lines do not interfere with the ground current, electromagnetic interference is suppressed, and the shield performance is improved. For example, it is possible to suppress a resonance phenomenon that is often found in conventional multilayer circuit boards and that occurs over the entire multilayer circuit board in which a solid power source or ground is generated as a resonator.

Further, in the high frequency circuit of the present invention, regarding the electrical connection between the strip line including the strip line of the triplate and the coaxial line, the central conductor exposed at the tip of the coaxial line forms the strip line. The inner conductor of the strip line on the uppermost layer of the multilayer circuit board is electrically connected to the through hole of the via and electrically connected by soldering, etc., and exposed near the tip of the coaxial line. The outer conductor is electrically connected to a metal pattern such as a pad electrically connected to the ground of the strip line by soldering or the like.

As a result, poor connection between the strip line and the coaxial line can be reduced, and since the central conductor of the coaxial line and the inner conductor of the strip line are almost directly connected to each other, the high frequency characteristic is excellent and the band is wide. A highly consistent connection can be achieved.

Further, in the high frequency circuit of the present invention, in the electrical connection between the strip line including the strip line of the triplate and the coaxial line, the coaxial pattern exposed together with the ground pattern provided on the uppermost layer of the multilayer circuit board is provided. A metal casing that shields the center conductor of the line is closely attached to the ground of the strip line and the outer conductor of the coaxial line and electrically connected by soldering, and the metal casing is bolted and nutd from both sides of the multilayer board. It is characterized by being fixed in.

As a result, the periphery of the exposed central conductor of the coaxial line is surrounded by the conductor, so that the shield performance is improved. Further, it becomes mechanically strong, and a stable connection state can be maintained even against stress on the multilayer circuit board and the coaxial line.

In the shielded loop type magnetic field detector of the present invention, the strip line of the lead portion or the loop portion of the shielded loop type magnetic field detector formed of the triplate strip line is formed of the above strip line of the present invention. Is characterized by.

As a result, when the output due to the magnetic field detected in the loop portion propagates to the lead portion as a stripline mode, the shielding performance of the stripline is improved, so that the influence of leakage of the propagating mode and the influence of ambient noise. Suppressed.

Further, even when a loop, which is a magnetic field detecting section, approaches a measurement object having a complicated electromagnetic field distribution, the shield performance of the loop section is improved, and therefore, a magnetic field other than the target magnetic field is unnecessary. The influence of electromagnetic field components is suppressed, and highly reliable magnetic field measurement becomes possible.

The shielded-loop magnetic field detector of the present invention is the above shielded-loop magnetic field detector, wherein the center of the two ground patterns facing each other in the width direction is located in the loop half-circumferential portion having no inner conductor. A via that electrically short-circuits the two grounds is formed, and a plurality of vias are provided over the half circumference of the loop.

As a result, the output due to the magnetic field detected in the loop portion propagates to the lead portion as a strip line mode, but the leakage of the propagating mode and the influence of ambient noise are suppressed because the shield performance of the strip line is improved. Contribute to doing. In addition, even when the loop that is the magnetic field detection unit is approached to the measurement object showing a complicated electromagnetic field distribution,
Since the shield performance of the loop is improved, the influence of unnecessary electromagnetic field components other than the target magnetic field is suppressed, and highly reliable magnetic field measurement becomes possible. By connecting both ends and the center of the two grounds in the semi-circumferential direction in the width direction with vias and short-circuiting, the impedance of the ground is reduced, and highly reliable magnetic field measurement becomes possible. Further, it is possible to prevent an unnecessary electromagnetic field from the measurement object from entering between the two grounds and causing an unnecessary mode to deteriorate the characteristics.

[0032]

FIG. 1 is an exploded perspective view of a high frequency circuit showing a first embodiment of the present invention. In FIG. 1, an inner conductor 101 of a strip line is formed on one unexposed layer of a multilayer circuit board having at least three layers, and a ground 102 is formed above and below the inner conductor 101 with an insulator interposed therebetween. The strip line 10 of triplate
Make up three.

The inner conductor 101 is a thin metal wire or metal film having a constant width, and the two grounds 102 formed above and below the inner conductor 101 are 10 or more than the inner conductor 101.
It is composed of a metal pattern having a finite width of about twice or less. The two grounds 102 have the same width. However, unlike the conventional high-frequency circuit, it is not shared with the entire printed circuit board or the adjacent transmission line such as the strip line 104 or the high-frequency circuit.

Similarly, the inner conductors 105 of the adjacent strip lines are also thin metal wires or metal films having a constant width, and the two grounds 1 formed above and below the inner conductor 105.
06 is composed of a metal pattern having a finite width of about 10 times or less than that of the inner conductor 105, and the two grounds 106 have the same width.

As a result, the adjacent strip lines 1
The ground currents 03 and 104 do not interfere with each other, electromagnetic interference is suppressed, and the shield performance is improved. For example,
It is possible to suppress a resonance phenomenon that occurs in the entire multilayer circuit board that uses solid power sources and grounds as a resonator, which is often seen in conventional multilayer circuit boards.

In this way, the stripline ground 1
02 has a finite width as described above, and in order to further improve the shield performance, both ends of the two grounds having a finite width in the width direction are electrically short-circuited by the via 107. A plurality of vias 107 are formed at both ends in the width direction of the ground 102 in the longitudinal direction which is the transmission direction of the strip line 103. Via 107
Regarding the lateral position of, it is sufficient that all or part of the via annular portion is electrically connected to the ground pattern,
It is desirable to provide the inner conductor 101 at symmetrical positions with respect to the center.

Regarding the position of the via 107 in the longitudinal direction, it is desirable that the pitch with the adjacent via 108 is 1/6 or less of the transmission signal wavelength. In this way, the adjacent strip lines are independently provided with vias for increasing the isolation, whereby electromagnetic interference is suppressed and the shield performance is improved.

FIG. 2 is an exploded perspective view of a high frequency circuit showing a second embodiment of the present invention, which relates to a connection structure between a strip line and a coaxial line in the first embodiment of the present invention. is there.

In FIG. 2, the inner conductor 201 is formed on one unexposed layer of the multi-layer circuit board 200 having at least three layers, and the ground 202 is sandwiched above and below the inner conductor 201. Formed to form a triplate strip line 203.

One end of the inner conductor 201 in the inner layer in the longitudinal direction is led to the uppermost layer 205 via the via 204 and electrically connected to the pad 206 formed in the uppermost layer 205. Similarly, one end in the longitudinal direction of the ground 207 on the lower side of the strip line 203 is led to the ground 209 on the upper side, that is, the uppermost layer 205 via the via 208 to electrically connect the two grounds. Furthermore, in order to improve the shield performance of the inner conductor 201, the inner conductor 20
A plurality of vias 208 are provided so as to surround one via 204.

On the other hand, in the coaxial line 210, the outer conductor and the insulator are removed by an appropriate length while leaving only the central conductor 211 at the tip in the longitudinal direction. As the coaxial line 210, for example, a semi-rigid coaxial cable is used.
The coaxial line 210 is placed parallel to the uppermost layer 205 of the multilayer circuit board. The tip of the center conductor 211 of the coaxial line 210 is bent with a roundness, and the inner conductor 20 of the strip line is bent.
1 is inserted into the through hole of the via 204 provided for electrical continuity with the pad 20 and is connected to the pad 20 by means of soldering 212 or the like.
6 is electrically connected.

In this case, better electrical connection can be obtained by pouring the solder 212 into the through hole. The outer conductor 213 of the coaxial line 210 is electrically connected to the ground in the uppermost layer of the multilayer circuit board by means of soldering 214 or the like. This makes it possible to reduce connection failures, and since it is close to a state in which the center conductor 211 of the coaxial line 210 and the inner conductor 201 of the strip line are directly connected, excellent high-frequency characteristics and high-coherence connection over a wide band are achieved. Can be achieved.

FIG. 3 is an exploded perspective view of a high-frequency circuit showing a third embodiment of the present invention, which relates to the connection structure between the strip line and the coaxial line in the first embodiment of the present invention. is there.

In this embodiment, the inner conductor 3 is formed on one unexposed layer of the multilayer circuit board 300 having four or more layers.
01 and the ground 302 is formed above and below the inner conductor 301 with the insulator sandwiched therebetween, thereby forming the triplate strip line 303.

One end in the longitudinal direction of the inner conductor 301 in the inner layer is led to the uppermost layer 305 via the via 304 and connected to the pad 306 formed on the uppermost layer 305. Similarly, one end in the longitudinal direction of the ground 302 in the inner layer is led to the uppermost layer 305 via the via 307 and connected to the pad 308 formed in the uppermost layer 305. Further, in order to enhance the shield of the inner conductor 301, a plurality of vias 307 are provided so as to surround the via 304 of the inner conductor 301.

In this embodiment, the uppermost layer 305 of the multilayer circuit board and the upper ground 309 of the strip line are used.
This is the case where the layers forming are not the same layer and there are other layers between them. On the other hand, in the coaxial line 310, at one end in the longitudinal direction, only the central conductor 311 is left and the outer conductor and the insulator are removed by an appropriate length. Coaxial line 3
For example, a semi-rigid coaxial cable is used as 10. The coaxial line 310 is placed parallel to the uppermost layer 305 of the multilayer circuit board.

The central conductor 311 at one end of the coaxial line 310 is bent with a roundness, inserted into a via 304 provided for conducting with the inner conductor 301 of the strip line, and electrically connected to the pad 306 by means of soldering 312 or the like. Connected to each other. In this case, better electrical connection can be obtained by pouring the solder 312 into the through hole.
Further, the outer conductor 313 of the coaxial line 310 is soldered 31
4 and the like, it is electrically connected to the ground pad 308 in the uppermost layer 305 of the multilayer circuit board.

FIG. 4 is an exploded perspective view of a high frequency circuit showing a fourth embodiment of the present invention. In the second embodiment of the present invention, the shield reinforcement of the central conductor of the exposed coaxial line is enhanced. Is intended.

In this embodiment, in the connection structure of the strip line and the coaxial line in the second embodiment,
In order to further improve the shielding performance, a connection part between the strip line and the coaxial line is formed by a metal housing capable of solder connection or a housing having a surface coating such as plating made of a metal capable of solder connection (hereinafter referred to as a metal housing) 401. Covers. Metal housing 4
As 01, for example, a housing made of copper is used.

The connecting portion between the multilayer circuit board 403 on which the strip line 402 is formed and the coaxial line 404 is covered with a metal casing 401 which is processed into a rectangular shape, and the coaxial line 404 is pressed down so that at least both sides of the coaxial line 404 are pressed. Two
Multi-layer circuit board 40 with bolts 405 and nuts 406
Fix to 3. The contact surfaces of the metal casing 401 and the pads 407 of the multilayer circuit board 403 are parallel to each other and have good adhesion.

Further, the metal casing 401 may be electrically connected to the pad 407 so as to surround the central conductor 409 by means such as soldering 408. Metal housing 401
Is of a size and structure that makes electrical contact with the coaxial line 404, and it is desirable to electrically connect both by means such as soldering. In FIG. 4, the metal casing 401 has a rectangular shape, but if it can be formed into an arc shape in order to improve the adhesion with the coaxial line 404, the shield performance will be further improved.

FIG. 5 is an exploded perspective view of a high frequency circuit showing a fifth embodiment of the present invention. In the third embodiment of the present invention, the shield reinforcement of the central conductor of the exposed coaxial line is enhanced. The basic configuration is
This is the same as the embodiment.

The connecting portion between the multilayer circuit board 503 on which the strip line 502 is formed and the coaxial line 504 is connected to the metal casing 5
01, and press down the coaxial line 504 so that at least two locations on both sides of the coaxial line 504 are covered with bolts 50.
5 and a nut 506 are fixed to the multilayer circuit board 503. The contact surfaces of the metal housing 501 and the pads 507 of the multilayer circuit board 503 are parallel to each other, and have good adhesion.

The metal casing 501 is provided with a pad 50 so as to surround the center conductor 509 by means of soldering 508 or the like.
7 may be electrically connected. Further, the metal casing 501 has a size and a structure that makes electrical contact with the coaxial line 504, and it is desirable to electrically connect the two by means of soldering or the like. In the figure, the metal housing 501 has a rectangular shape, but if it can be formed into an arc shape in order to enhance the adhesion with the coaxial line, the shield performance will be further improved.

FIG. 6 is an exploded perspective view of a shielded loop type magnetic field sensor showing a sixth embodiment of the present invention.
By adopting the strip line structure according to the first embodiment of the present invention, the shield performance is improved.

In FIG. 6, an inner conductor 602 is formed on one unexposed layer of a multilayer circuit board 601 having at least three layers, and a ground 603 is formed above and below the inner conductor with an insulator interposed therebetween. Thus, a triplate strip line 604 is configured. An insulator may be provided on one or both of the upper ground and the lower ground to increase the strength of the substrate.

A straight strip line extending from the left end is a lead portion 605, and a portion bent at a right angle at a right angle to form a square is a loop portion 606. Loop part 60
The end 607 of 6 is the ground 60 of the strip line 604.
Shorted to 3. Two grounds 6 of the lead portion 605
03 is short-circuited at both ends in the width direction via the via 608, and a plurality of vias 608 are provided along the longitudinal direction of the lead portion 605.

The loop portion 606 forms a square loop opening 610 having a void 609 at the right end. In addition, the inner conductor 602 is formed on the first half peripheral portion 61 of the loop portion 606.
No. 1, which is provided on the first half, and which is electrically connected to the end of the ground in the second half peripheral portion 613 through the via 612 after traversing the void 609 of the ground 603.

With the above structure, the output generated by the magnetic field interlinking the loop opening 610 propagates to the left end through the lead portion 605 in the strip line mode.
According to the present embodiment, the influence of the stripline mode leakage from the lead portion 605 and the influence of ambient noise entering from the lead portion 605 can be suppressed, and highly reliable magnetic field measurement can be performed.

FIG. 7 is an exploded perspective view of a shielded loop type magnetic field sensor showing a seventh embodiment of the present invention.
The stripline structure according to the first embodiment of the present invention is extended to the first half of the lead portion and the loop portion and applied, whereby the shield performance is further improved.

In FIG. 7, an inner conductor 702 is formed on one unexposed layer of a multilayer circuit board 701 having at least three layers, and a ground 703 is formed above and below the inner conductor with an insulator interposed therebetween. And constitutes a triplate strip line 704. An insulator may be provided on one or both of the upper ground and the lower ground to increase the strength of the substrate.

A straight strip line extending from the left end is a lead portion 705, and a portion formed by bending a right angle on the right side to form a square is a loop portion 706. Loop part 70
The end 707 of 6 is the ground 70 of the strip line 704.
Shorted to 3. Lead portion 705 and loop portion 706
The two grounds 703 of the strip line forming the first half-circumferential portion 711 of the
08 is short-circuited, and a plurality of vias 708 are provided along the longitudinal direction.

The loop portion 706 has a void 709 at the right end and forms a square loop opening 710. Further, the inner conductor 702 is provided in the first half-circumferential portion 711 of the loop portion, and after passing through the void 709 of the ground, the via 7 is formed.
It is electrically connected to the end portion of the ground in the second half peripheral portion 713 via 12. With the above configuration, the output generated by the magnetic field interlinking the loop opening 710 propagates to the left end via the lead portion 705 in the strip line mode.

According to the present embodiment, leakage of the strip line mode from the first half peripheral portion 711 and the lead portion 705 of the loop portion, or the first half peripheral portion 711 of the loop portion.
Also, the influence of ambient noise penetrating from the lead portion 705 is suppressed, and more reliable magnetic field measurement becomes possible.

FIG. 8 is an exploded perspective view of a shielded loop type magnetic field sensor showing an eighth embodiment of the present invention.
By applying the stripline structure according to the first embodiment of the present invention by extending it to the first half circumference of the lead part and the loop part, and also applying it to the second half circumference part of the loop part, This is intended to further improve the shield performance.

In FIG. 8, an inner conductor 802 is formed on one unexposed layer of a multilayer circuit board 801 having at least three layers, and a ground 803 is formed above and below the inner conductor with an insulator interposed therebetween. And constitutes a triplate strip line 804. An insulator may be provided on one or both of the upper ground and the lower ground to increase the strength of the substrate.

The straight stripline extending from the left end is the lead portion 805, and the portion bent at a right angle at a right angle to form a square is a loop portion 806. Loop part 80
The terminal 807 of 6 is the ground 80 of the strip line 804.
Shorted to 3. Lead portion 805 and loop portion 806
The two grounds 803 of the strip line forming the first half-circumferential portion 808 of the
09, and a plurality of vias 809 are provided along the longitudinal direction.

In addition, the second half peripheral portion 81 of the loop portion 806
Both widthwise ends of two grounds of 0 are also vias 81
It is short-circuited through 1. The loop portion 806 has a void 812 at the right end and forms a square loop opening 813. Further, the inner conductor 802 is provided in the first half-circumferential portion 808 of the loop portion 806, and is electrically connected to the end of the ground in the second half-circumferential portion 810 via the via 814 after crossing the gap 812 in the ground. ing. With the above configuration, the output generated by the magnetic field interlinking the loop opening 813 propagates to the left end in the strip line mode.

According to the present embodiment, the influence of the stripline mode leakage from the stripline and the influence of ambient noise penetrating from the stripline can be suppressed, and more reliable magnetic field measurement can be performed. Further, for example, on the right side of the magnetic field detector, there is a magnetic field generation source having a complicated radiated electromagnetic field,
When the magnetic field detector approaches the magnetic field generation source, it is possible to suppress the influence of the unnecessary electromagnetic field and detect only the target magnetic field component, which enables highly reliable magnetic field measurement.

Further, according to the present embodiment, the vias 81 are provided at both ends of the second loop half-circumferential portion 810 having no inner conductor.
Since the two grounds are short-circuited via 1, the impedance of the ground is lowered and stable magnetic field measurement can be performed. Further, it is possible to suppress the deterioration of the characteristics due to the generation of an unnecessary mode by an unnecessary electromagnetic field entering between the two grounds.

FIG. 9 is an exploded perspective view of a shielded loop type magnetic field sensor showing a ninth embodiment of the present invention.
By applying the strip line structure according to the first embodiment of the present invention including the lead portion and the first and second half peripheral portions of the loop portion, the shield performance is further improved. .

In FIG. 9, an inner conductor 902 is formed on one unexposed layer of a multilayer circuit board 901 having at least three layers, and a ground 903 is formed above and below the inner conductor with an insulator interposed therebetween. And constitutes a triplate strip line 904. An insulator may be provided on one or both of the upper ground and the lower ground to increase the strength of the substrate.
The straight strip line extending from the left end is the lead portion 90.
The loop portion 906 is a portion that is bent at a right angle on the right side to form a rectangular shape.

The terminal 907 of the loop portion 906 is short-circuited to the ground 903 of the strip line 904. The two grounds 903 of the lead portion 905 are short-circuited via the vias 908 at both ends in the width direction.
Are provided in the longitudinal direction. Further, both ends in the width direction of the two grounds of the first half peripheral portion 909 and the second half peripheral portion 910 of the loop portion 906 are also short-circuited via the via 911.

The loop portion 906 has a void 912 at the right end and forms a square loop opening 913. Further, the inner conductor 902 is provided on the first half peripheral portion 909 of the loop portion, and after passing through the void 912 of the ground, the via 9 is formed.
It is electrically connected to the end of the ground in the second half peripheral portion 910 via 14. With the above configuration, the output generated by the magnetic field interlinking the loop opening 913 propagates to the left end in the strip line mode.

According to the present embodiment, the influence of the strip line mode leakage from the strip line and the influence of ambient noise penetrating from the strip line is suppressed, and highly reliable magnetic field measurement becomes possible. Also, for example, if there is a magnetic field generation source having a complicated radiated electromagnetic field on the right side of the magnetic field detector and the magnetic field detector approaches the magnetic field generation source, the effect of the unnecessary electromagnetic field is suppressed and the target magnetic field component is suppressed. Only the magnetic field can be detected, and highly reliable magnetic field measurement becomes possible.

Further, by short-circuiting the two grounds via the via 911 at both ends of the second loop half-circumferential portion 910 having no inner conductor, the impedance of the ground is lowered and stable magnetic field measurement can be performed. Further, it is possible to prevent an unnecessary electromagnetic field from entering between the two grounds and causing an unnecessary mode to deteriorate the characteristics.

FIG. 10 is an exploded perspective view of a shielded loop type magnetic field sensor showing a tenth embodiment of the present invention. The strip line structure according to the first embodiment of the present invention is used as a lead portion. The first half of the loop part and the second half part of the loop part are applied, and the center in the width direction of the second half part of the loop part that does not have an inner conductor is also short-circuited through the via to improve the shielding performance. This is a further improvement. Although this structure is applicable to the sixth to ninth embodiments, the case of being applied to the ninth embodiment will be described here.

In FIG. 10, an inner conductor 1002 is formed on one unexposed layer of a multilayer circuit board 1001 having at least three layers, and a ground 1003 is formed above and below the inner conductor with an insulator interposed therebetween. And constitutes a triplate strip line 1004. An insulator may be provided on one or both of the upper ground and the lower ground to increase the strength of the substrate.

The straight stripline extending from the left end is the lead portion 1005, and the portion bent in the right angle at right angles to form a square is the loop portion 1006. The terminal end 1007 of the loop portion 1006 is short-circuited to the ground 1003 of the strip line 1004. The two grounds 1003 of the lead portion 1006 have vias 1 at both ends in the width direction.
It is short-circuited via 008, and a plurality of vias 1008 are provided in the longitudinal direction.

Further, both ends in the width direction of the two grounds of the first half peripheral portion 1009 and the second half peripheral portion 1010 of the loop portion are short-circuited via the via 1011 to provide a plurality in the longitudinal direction. Further, the center in the width direction of the two grounds of the second half peripheral portion 1010 having no inner conductor of the loop portion 1006 is also short-circuited via the via 1012, and a plurality of vias are provided in the longitudinal direction.

The loop portion 1006 has a void 1013 at the right end.
Are provided to form a square loop opening 1014. Further, the inner conductor 1002 is provided in the first half peripheral portion 1009 of the loop portion 1006, and the void 1013 in the ground is provided.
Second half-circle 1 via via 1015 after crossing
It is electrically connected to the end of the ground at 010. With the above configuration, the output generated by the magnetic field interlinking the loop opening 1014 propagates to the left end in the strip line mode.

According to the present embodiment, the influence of the strip line mode leakage from the strip line and the influence of ambient noise penetrating from the strip line is suppressed, and highly reliable magnetic field measurement becomes possible. Also, for example, if there is a magnetic field generation source having a complicated radiated electromagnetic field on the right side of the magnetic field detector and the magnetic field detector approaches the magnetic field generation source, the effect of the unnecessary electromagnetic field is suppressed and the target magnetic field component is suppressed. Only the magnetic field can be detected, and highly reliable magnetic field measurement becomes possible.

Further, the vias 1011 and 101 are provided at both ends and the center of the second loop half-circumferential portion 1010 having no inner conductor.
By short-circuiting the two grounds via 2, the impedance of the ground is lowered and stable magnetic field measurement can be performed. Further, it is possible to suppress the deterioration of the characteristics due to the generation of an unnecessary mode by an unnecessary electromagnetic field entering between the two grounds.

[0084]

According to the present invention, the shield performance in the strip line of the triplate can be enhanced, the electromagnetic interference generated between the strip line and the adjacent circuit element or another strip line, and the surrounding environment. The influence of electromagnetic noise can be suppressed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a second embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a third embodiment of the present invention.

FIG. 4 is an exploded perspective view showing a fourth embodiment of the present invention.

FIG. 5 is an exploded perspective view showing a fifth embodiment of the present invention.

FIG. 6 is an exploded perspective view showing a sixth embodiment of the present invention.

FIG. 7 is an exploded perspective view showing a seventh embodiment of the present invention.

FIG. 8 is an exploded perspective view showing an eighth embodiment of the present invention.

FIG. 9 is an exploded perspective view showing a ninth embodiment of the present invention.

FIG. 10 is an exploded perspective view showing a tenth embodiment of the present invention.

FIG. 11 is an exploded perspective view showing a conventional example.

FIG. 12 is an exploded perspective view showing a conventional example.

FIG. 13 is an exploded perspective view showing a conventional example.

[Explanation of symbols]

101, 201, 301, 602, 702, 802, 9
02, 1002, 2001, 2101, 2202 Inner conductors 102, 202, 302, 603, 703, 803, 9
03,1003,2002,2102,2203 Ground 103,203,303,402,502,604,7
04,804,904,1004,2103,2204
Strip line 104 Adjacent line 105 Adjacent line inner conductor 106 Adjacent line ground 107, 204, 208, 304, 307, 608, 6
12,708,712,809,811,811,81
4,908,911,914,1008,1011,1
012, 1015, 2003, 2104, 2110, 2
209 vias 108 adjacent vias 205, 305, 2105 top layers 206, 209, 306, 308, 407, 507, 2
106, 2111 Pad 207 Lower ground 210, 310, 404, 504, 2107 Coaxial line 211, 311, 409, 509, 2108 Central conductor 212, 214, 312, 314, 408, 508, 2
109, 2113 Solder 213, 313, 2112 Outer conductor 309 Upper ground 401, 501 Metal housing 403, 503, 601, 701, 801, 901, 1
001, 2012 multilayer circuit boards 405, 505 bolts 406, 506 nuts 605, 705, 805, 905, 1005 lead parts 606, 706, 806, 906, 1006 loop parts 607, 707, 807, 907, 1007 end parts 609, 709, 812, 912, 1013, 2206
Voids 610, 710, 813, 913, 1014, 2207
Loop openings 611, 711, 808, 909, 1009, 2208
First loop half-surroundings 613, 713, 810, 910, 1010 Second loop half-surroundings 2205 Straight line

Claims (7)

[Claims] 1. A tri-plate strip line comprising an inner conductor formed in one unexposed layer of a multilayer circuit board and two grounds formed above and below the inner conductor with an insulator interposed therebetween. And a gland in which a loop opening having a void is formed at its tip, and a position that crosses the first half peripheral portion of the loop opening and the void and crosses the void. The loop portion having the inner conductor electrically connected to the end of the ground in the second half circumference of the loop opening via the via, and is generated by the magnetic field interlinking the loop opening. In the shielded loop magnetic field detector that propagates the output to the lead portion as a stripline mode, the stripline of the lead portion includes the inner conductor and the Along the conductor, said two ground sandwiching the inner conductor has a wide finite width than the pattern width of the inner conductor,
The inner conductor is provided along a longitudinal direction which is a transmission direction of the strip line, and is composed of a plurality of vias that short-circuit the two grounds at both ends in the width direction of the ground. Is a structure surrounded by the two grounds sandwiching it and the vias provided on both sides of the ground, the shielded loop type magnetic field detector. 2. The shielded loop according to claim 1, wherein both ends in the width direction of the two glands in the loop portion are short-circuited by vias, and a plurality of the vias are provided along a peripheral edge of the gland. Type magnetic field detector. 3. A strip line of a triplate comprising an inner conductor formed in one unexposed layer of a multilayer circuit board and two grounds formed above and below the inner conductor with an insulator sandwiched therebetween. And a gland in which a loop opening having a void is formed at its tip, and a position that crosses the first half peripheral portion of the loop opening and the void and crosses the void. The loop portion having the inner conductor electrically connected to the end of the ground in the second half circumference of the loop opening via the via, and is generated by the magnetic field interlinking the loop opening. In the shielded loop magnetic field detector for propagating the output to the lead portion as a stripline mode, a strike of the first half circumference portion of the lead portion and the loop portion is provided. The up line includes the inner conductor, the two grounds along the inner conductor, the two grounds having a finite width wider than the pattern width of the inner conductor and sandwiching the inner conductor, and the transmission direction of the strip line. Is provided along the longitudinal direction,
It is composed of a plurality of vias that short-circuit the two grounds at both ends in the width direction of the ground, and in a cross section including the vias, the inner conductor is provided on both sides of the two grounds sandwiching the inner conductor and the ground. A shielded loop type magnetic field detector having a structure surrounded by the vias. 4. The vias are short-circuited at both ends in the width direction of the two grounds in the second half peripheral portion having no inner conductor, and a plurality of the vias are provided along a loop peripheral edge of the ground. The shielded loop type magnetic field detector according to claim 3. 5. The two grounds are short-circuited by vias at the center in the width direction of the two ground patterns in the second loop half-circumferential portion having no inner conductor, and
The shielded loop type magnetic field detector according to any one of claims 1 to 4, wherein a plurality of the vias are provided over the second loop half circumference portion. 6. The pattern width of the two grounds sandwiching the inner conductor is a finite width that is about 10 times or less the pattern width of the inner conductor, according to any one of claims 1 to 5. Shielded loop type magnetic field detector. 7. The pitch interval in the longitudinal direction of the vias is
The shielded loop type magnetic field detector according to any one of claims 1 to 6, which has a transmission signal wavelength of 1/6 or less.