JP2001289894A - Electromagnetic wave measurement cell - Google Patents

Abstract

(57) [Problem] To provide an electromagnetic wave measuring cell capable of easily and quickly measuring electromagnetic waves over a wide range of frequencies. An electromagnetic wave measurement cell includes a shield case and an internal conductor. A rectangular side plate 18 is detachably attached to one side surface of the shield case 11. An internal conductor 22 is connected between one terminal 20 and the other terminal 21 of the shield case 11. The resonance frequency of the electromagnetic wave measurement cell 10 can be changed by, for example, manually moving up and down a predetermined range to change the shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave measuring cell used for measuring an electromagnetic wave emitted by a circuit under test during operation, and in particular, to easily and quickly measure an electromagnetic wave over a wide range of frequencies. The present invention relates to an electromagnetic wave measurement cell.

[0002]

2. Description of the Related Art An electromagnetic wave measuring cell is often used to measure an electromagnetic wave emitted by a semiconductor integrated circuit or the like during operation. An electromagnetic wave measuring cell generally includes an inner conductor that receives an electromagnetic wave emitted by a circuit under test, a shield case that shields the inner conductor from electromagnetic waves other than the electromagnetic wave emitted by the circuit under test, and the like. Since the inner conductor has a function of transmitting an electric signal and a function of an antenna, it can reversibly radiate an electromagnetic wave toward the circuit under test.

[0003] The shield case is usually formed in a housing shape so as to cover the inner conductor, and is provided with two terminals for inputting and outputting electric signals and a mounting port for a circuit to be inspected.
The inner conductor is connected between the two terminals. The circuit under test emits electromagnetic waves generated by the operation of the circuit.
On the other hand, the internal conductor of the electromagnetic wave measuring cell generates an electric signal corresponding to the received electromagnetic wave between the two terminals.

Therefore, one terminal is terminated by a terminating resistor, and an electric signal output from the other terminal is displayed on a measuring instrument (for example, a spectrum analyzer) to measure an electromagnetic wave radiated by the circuit under test. be able to.

By the way, such an electromagnetic wave measuring cell is
It has the property of electrically resonating at a specific frequency with respect to an input signal or an electric signal obtained from a received electromagnetic wave. This resonance frequency is determined by the stray capacitance and the shape of the internal conductor that are structurally present inside the electromagnetic wave measuring cell, the wiring layout inside the electromagnetic wave measuring cell, and the like.

Therefore, conventionally, when measuring electromagnetic waves over a wide range of frequencies, a plurality of electromagnetic wave measuring cells corresponding to the frequencies of the electromagnetic waves to be measured are prepared in advance, and one of these cells is measured. The measurement was performed by sequentially selecting cells. That is, each time the frequency of the electromagnetic wave to be measured overlaps with the resonance frequency of the selected electromagnetic wave measuring cell, the cell is replaced with another electromagnetic wave measuring cell and measurement of the electromagnetic wave is restarted.

[0007]

However, when measuring electromagnetic waves over a wide range of frequencies by the above method, there are the following problems. (1) Since it is necessary to prepare a plurality of electromagnetic wave measurement cells in advance, the economic burden is large. (2) Every time the frequency of the electromagnetic wave to be measured overlaps with the resonance frequency of the selected electromagnetic wave measuring cell, a troublesome operation of replacing the cell with another electromagnetic wave measuring cell is required. (3) In the case where the circuit to be inspected operates by a signal supplied from the outside, wiring is assembled through a hole previously formed in the substrate of the inspection circuit, and then the inspection circuit is mounted on the shield case of the electromagnetic wave measurement cell. Although it is attached, a subtle difference in wiring layout inside the electromagnetic wave measurement cell strongly affects the measurement of electromagnetic waves. For this reason, it is practically difficult to reproduce the measurement conditions before replacement using the replaced electromagnetic wave measurement cell.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic wave measuring cell capable of easily and quickly measuring electromagnetic waves over a wide range of frequencies.

[0009]

In order to solve the above problems, an electromagnetic wave measuring cell according to the present invention is an electromagnetic wave measuring cell used for measuring an electromagnetic wave radiated by a circuit to be inspected. A shield case that is connected and receives an electromagnetic wave radiated by the circuit under test; and a mounting case for the circuit under test is provided to shield the internal conductor from electromagnetic waves other than the electromagnetic wave radiated by the circuit under test. A mechanism capable of changing the shape to change the electrical resonance frequency of the electromagnetic wave measurement cell.

In the electromagnetic wave measuring cell according to the present invention,
When the frequency of the electromagnetic wave radiated by the circuit under test and the resonance frequency of the electromagnetic wave measurement cell overlap, the shape of the internal conductor is changed to change the resonance frequency. Therefore, the economic burden,
Electromagnetic waves over a wide range of frequencies can be easily and quickly measured without the need for troublesome work of replacing the electromagnetic wave measuring cell and reproducing the electromagnetic wave measurement conditions.

For example, an internal conductor is connected between two terminals so that at least a part of the internal conductor is movable, or an internal conductor is formed by combining a plurality of conductor plates slidable with each other. A change in the shape of the conductor can be realized. In this case, the predetermined portion of the shield case can be detached or opened and closed, and the shape of the internal conductor can be manually changed after removing or opening the predetermined portion of the shield case. Further, a mechanism including at least one screw for changing the shape of the internal conductor is provided in the shield case, and the required number of screws are tightened or loosened by a desired amount, so that the shape of the internal conductor can be changed.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment of the present invention will be described with reference to FIGS.

The electromagnetic wave measuring cell 10 is a device for measuring an electromagnetic wave emitted by a circuit to be inspected such as a semiconductor integrated circuit during operation. This electromagnetic wave measuring cell 10 is configured around a shield case 11 and an internal conductor 22.

The shield case 11 has a rectangular cylindrical shape tapering toward both ends. Shield case 11
As shown in the plan view (A) of FIG. 1, a square mounting opening 12 is formed on the upper surface of the. Mounting port 12
Is set slightly smaller than the substrate of the circuit to be inspected. The circuit to be inspected is set in the mounting port 12 with the side on which the circuit element is incorporated facing downward.

[0015] 4 of the mounting opening 12 of the shield case 11
A fixing device 13 for fixing the set circuit to be inspected is attached to each of the corners. Fixing device 13
As shown in the side view (B) of FIG.
The movable member 15, the holding member 16 and the lever 17 are included.

The basic member 14 of the fixing device 13 has a convex shape and is screwed to the upper surface of the shield case 11. One end of the movable member 15 is rotatably supported at the center of the basic member 14. On the other hand, the other end of the movable member 15 is divided into two as shown in FIG. 1A, and is fixed with one end of the holding member 16 interposed therebetween. The other end of the holding member 16 is shown in FIG.
As shown in (1), the circuit to be inspected is smoothly pressed. One end of the lever 17 is rotatably supported at the center of the basic member 14. The other end of the lever 17 has a shape that can be pinched by a user.

The operation of fixing the circuit to be inspected by the fixing device 13 is performed according to the following procedure. First, the lever 17 is pivoted upward as much as possible. Next, after the holding member 16 is pivoted upward as much as possible, the circuit to be inspected is set in the mounting port 12. Further, the holding member 16 is rotated downward to hold the set circuit to be inspected. Then, the circuit to be inspected is fixed to the mounting opening 12 by rotating the lever 17 to the state shown in FIG. 1B to prevent the holding member 16 from rotating.

As shown in FIG. 1B, a rectangular side plate 18 is fixed to one side surface of the shield case 11 with four screws 19. That is, by removing the side plate 18 from the shield case 11, the inside of the shield case 11 can be exposed.

As shown in FIGS. 1A to 1C, electric signal input / output terminals 20 and 21 are attached to both ends of the shield case 11, respectively. For example, when measuring an electromagnetic wave radiated from a circuit under test, one terminal 20 is terminated with a terminating resistor and the other terminal 2 is terminated.
1 is connected to a measuring instrument (such as a spectrum analyzer). Also, when measuring the transfer characteristics of the inner conductor 22,
One terminal 20 can be selected for input and the other terminal 21 can be selected for output. One terminal 20 and the other terminal 21
The inner conductor 22 is connected between the inner conductor 22 and the inner conductor 22, as shown in a side view (C) of FIG. I can do it.

The inner conductor 22 is a flat plate tapering toward both ends, has a predetermined characteristic impedance (for example, 50Ω), and is supplied through one of the terminals 20 and 21. It has a function of transmitting an electric signal to the other of the terminals 20 and 21, a function of transmitting and receiving an electromagnetic wave, and a function of shifting the electric resonance frequency of the electromagnetic wave measurement cell 10.

That is, for example, when the terminal 20 is used for input and the terminal 21 is used for output, an electric signal corresponding to the electric signal input to the terminal 20 is output from the terminal 21. On the other hand, when the terminal 20 is terminated by a terminating resistor (for example, 50Ω) and the terminal 21 is connected to a measuring instrument, the internal conductor 2
2 outputs from the terminal 21 an electric signal corresponding to the received electromagnetic wave.

By electrically connecting the electromagnetic wave measuring cell 10 of this embodiment to a spectrum analyzer or the like,
The frequency component of the electromagnetic wave received by the internal conductor 22 is displayed, and the electromagnetic wave emitted by the circuit under test can be measured.

The electromagnetic wave measuring cell 10 has a property of electrically resonating at a specific frequency with respect to an input signal or an electric signal obtained from a received electromagnetic wave. The resonance frequency is determined by the stray capacitance structurally present between the internal conductor 22 and the shield case 11, the shape of the internal conductor 22, the wiring inside the shield case 11, and the like.

Therefore, in the present embodiment, the resonance frequency of the electromagnetic wave measuring cell 10 can be shifted by manually moving at least a part of the internal conductor 22 up and down by a desired amount. That is, for example, as shown in FIG.
By manually depressing the horizontally extended inner conductor 22 (solid line and dotted line) downward by a desired amount (dashed line), the resonance frequency (local pulse) of the inner conductor 22 can be determined, for example, by using FIG.
As shown in (2), it is possible to shift from the position shown by the solid line to the position shown by the dotted line.

Therefore, in the present embodiment, when the resonance frequency of the electromagnetic wave measuring cell 10 and the frequency of the electromagnetic wave radiated by the circuit under test overlap, at least a part of the internal conductor 22 is manually moved up and down by a desired amount. By shifting the resonance frequency, the measurement of the electromagnetic waves emitted from the circuit under test can be restarted easily and quickly without the need for an economic burden, replacement of the electromagnetic wave measurement cell, or the need to reproduce the electromagnetic wave measurement conditions. it can.

Next, a second embodiment of the present invention will be described with reference to FIG. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 3, the inner conductor 23 according to the present embodiment slidably combines a flat conductor plate 23A tapered toward both ends and a substantially triangular conductor plate 23B. It is composed. The shape of the conductor plate 23B is determined so that the conductor plate 23B can slide within a predetermined range in the X-axis direction with respect to one end of the conductor plate 23A. A handle 23C is provided on a part of the conductor plate 23B.

Therefore, in the present embodiment, when the resonance frequency of the electromagnetic wave measuring cell 10 and the frequency of the electromagnetic wave radiated by the circuit to be inspected overlap, the conductor plate 23B is moved to one end of the conductor plate 23A. By manually sliding in the X-axis direction by the desired amount and shifting the resonance frequency, the circuit to be inspected can be economically loaded, without the need to replace the electromagnetic wave measurement cell or to reproduce the electromagnetic wave measurement conditions. Measurement of the emitted electromagnetic waves can be resumed easily and quickly.

Next, a third embodiment of the present invention will be described with reference to FIG. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 4, the inner conductor 24 according to the present embodiment is formed by slidably combining a flat conductor plate 24A tapered toward both ends and a substantially triangular conductor plate 24B. It is composed. The shape of the conductor plate 24B is such that the conductor plate 24B has a fulcrum 24 with respect to one end of the conductor plate 24A.
It is determined so that it can slide within a predetermined range around C.

A sliding member (details omitted) for sliding the conductor plate 24B with respect to one end of the conductor plate 24A about the fulcrum 24C is provided in the shield case 1.
1 is attached to one side surface. This sliding tool includes a screw 25 whose tip is connected to the conductor plate 24B via a connecting tool. That is, by tightening or loosening the screw 25 by a desired amount, the conductor plate 24B can be slid with respect to one end of the conductor plate 24A about the fulcrum 24C by a predetermined amount.

Therefore, in the present embodiment, when the resonance frequency of the electromagnetic wave measuring cell 10 and the frequency of the electromagnetic wave radiated by the circuit to be inspected overlap, the screw 25 is tightened or loosened by a desired amount and the inner conductor 24 is removed. By shifting the resonance frequency, the measurement of the electromagnetic wave radiated from the circuit under test can be restarted easily and quickly without the need for an economic burden, replacement of the electromagnetic wave measuring cell, and reproduction of the electromagnetic wave measurement conditions.

In the present embodiment, the electromagnetic wave measuring cell 10 is set by tightening or loosening the screw 25.
Can be shifted, so that the operability can be improved as compared with the first or second embodiment.

Next, a fourth embodiment of the present invention will be described with reference to FIG. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 5, the inner conductor 26 according to the present embodiment slidably combines a flat conductor plate 26A tapered toward both ends and a substantially rectangular conductor plate 26B. It is composed. The shape of the conductor plate 26B is determined so that the conductor plate 26B can slide within a predetermined range in the Y-axis direction with respect to the center of the conductor plate 26A.

A sliding member (details omitted) for sliding the conductive plate 26B in the Y-axis direction with respect to one end of the conductive plate 26A is attached to one side surface of the shield case 11. . The slide tool has a screw 27 whose tip is connected to the conductor plate 26B via a connector.
including. That is, by tightening or loosening the screw 27 by a desired amount, the conductor plate 26B can be slid in the Y-axis direction by a predetermined amount with respect to one end of the conductor plate 26A.

Therefore, in the present embodiment, when the resonance frequency of the electromagnetic wave measuring cell 10 and the frequency of the electromagnetic wave radiated by the circuit to be inspected overlap, the screw 27 is tightened or loosened by a desired amount, and the internal conductor 26 By shifting the resonance frequency, the measurement of the electromagnetic wave radiated from the circuit under test can be restarted easily and quickly without the need for an economic burden, replacement of the electromagnetic wave measuring cell, and reproduction of the electromagnetic wave measurement conditions.

In this embodiment, the electromagnetic wave measuring cell 10 is
Can be shifted, so that the operability can be improved as compared with the first or second embodiment.

Further, in the present embodiment, since the amount of deformation of the internal conductor 26 is larger than the amount of deformation of the internal conductor 24 of the third embodiment, the shift amount of the resonance frequency of the electromagnetic wave measuring cell 10 can be increased. It is possible to measure electromagnetic waves over a wider range of frequencies as compared with the third embodiment.

[0037]

As described above, according to the present invention, it is possible to reduce the frequency of electromagnetic waves over a wide range of frequencies without the need for an economic burden, replacement of the electromagnetic wave measuring cell, and the need to reproduce the electromagnetic wave measurement conditions. Measurement can be performed easily and quickly.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an electromagnetic wave measuring cell according to a first embodiment of the present invention, (A) is a plan view of the electromagnetic wave measuring cell, and (B) is a side surface on one side of the electromagnetic wave measuring cell. It is a figure, (C) is a side view when the side plate is removed from the shield case shown in (B).

FIG. 2 is a diagram illustrating a shift of a resonance frequency before and after deformation of an internal conductor of FIG. 1;

FIG. 3 is an enlarged plan view showing one end of an internal conductor constituting an electromagnetic wave measuring cell according to a second embodiment of the present invention.

FIG. 4 is an enlarged plan view showing one end of an internal conductor constituting an electromagnetic wave measuring cell according to a third embodiment of the present invention.

FIG. 5 is an enlarged plan view showing one end of an inner conductor constituting an electromagnetic wave measuring cell according to a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Electromagnetic wave measurement cell 11 Shield case 12 Inspection port of circuit to be inspected 13 Fixing device 14 Basic member 15 Movable member 16 Holding member 17 Lever 18 Side plate 19 Screw 20, 21 Terminal 22, 23, 24, 26 Internal conductor 25, 27 Screw 23A , 23B, 24A, 24B, 26A, 26B Conductor plate 23C Handle 24C Support point

Claims (5)

[Claims] 1. An electromagnetic wave measuring cell used for measuring an electromagnetic wave radiated by a circuit under test, comprising: an inner conductor connected between two terminals for receiving the electromagnetic wave radiated by the circuit under test; An installation port for the circuit under test is provided, and a shield case for shielding the internal conductor from electromagnetic waves other than the electromagnetic waves radiated by the circuit under test, and changing the shape of the internal conductor to electrically connect the electromagnetic wave measurement cell. An electromagnetic wave measurement cell, comprising: a mechanism capable of changing a resonance frequency. 2. The shield case, wherein at least a part of the inner conductor is connected between the two terminals so as to be movable, and a predetermined portion of the shield case is configured to be detachable or openable. 2. The electromagnetic wave measuring cell according to claim 1, wherein after removing or opening the predetermined portion, at least a part of the internal conductor is moved by a desired amount to change the shape. 3. The shield case is provided with a mechanism including at least one screw for moving at least a part of the inner conductor, and a required number of screws are tightened or loosened by a desired amount. The electromagnetic wave measuring cell according to claim 1, wherein the shape of the internal conductor is changed. 4. The shield according to claim 1, wherein the inner conductor is formed by combining a plurality of conductive plates so as to be slidable with each other; After removing or opening a predetermined part of the case, at least one of the plurality of conductor plates is slid by a desired amount to change the shape of the internal conductor. 2. The cell for measuring electromagnetic waves according to 1. 5. The internal conductor includes a plurality of conductor plates slidably combined with each other, and the shield case includes at least one of the plurality of conductor plates in the shield case. 2. A mechanism including at least one screw for sliding the inner conductor is provided, and the shape of the inner conductor is changed by tightening or loosening a required number of screws by a desired amount. Electromagnetic wave measurement cell.