JP3912428B2 - Method and apparatus for measuring high-frequency electrical characteristics of electronic components, and calibration method for high-frequency electrical characteristics measuring apparatus - Google Patents

Description

The present invention relates to a method for measuring high-frequency electrical characteristics of electronic components such as filters, couplers, and baluns, or impedance elements such as chip inductors and chip capacitors. More specifically, the present invention relates to a method for correcting a measurement error when measuring a scattering coefficient or impedance value of the electronic component using a measuring instrument such as a network analyzer.

When measuring high-frequency electrical characteristics of impedance elements such as surface mount type filters and couplers, or chip inductors using a network analyzer, it is impossible to connect a coaxial cable directly to these electronic components. Usually, a planar transmission line (such as a microstrip line or a coplanar waveguide) is connected to a network analyzer via a coaxial cable, and an electronic component is brought into contact with the planar transmission line for measurement. In this case, in order to obtain the true value of the scattering coefficient matrix of the impedance element that is the subject, it is necessary to identify the error factor of the measurement system and remove the influence of the error factor from the measurement result. This is called correction or calibration.

As shown in Non-Patent Document 1, TRL (Through-Reflection-Load) correction and SOLT (Short-Open-Load-Through) correction are known as conventional techniques for removing measurement system errors in measurement using a network analyzer. It has been.

1 and 2 show a measurement system using a network analyzer, and error models used in SOLT correction and TRL correction.
The electronic component 1 that is the subject is connected to a transmission path formed on the upper surface of the measurement jig 2. Both ends of the transmission path of the measurement jig 2 are connected to a measurement port of a network analyzer (not shown) via a coaxial cable 3.
In the error model for SOLT correction, S _{11A to} S _22A are the scattering coefficients of the transmission path including the subject, E _DF, E _{RF and} E _SF are the scattering coefficients of one measurement port, and E _{LF and} E _TF are the other measurement Port side scattering coefficient.
In the error model for TRL correction, S _{11A to} S _22A are the scattering coefficients of the object, e _{00 to} e ₁₁ are the scattering coefficients on one measurement port side, and f _{00 to} f ₁₁ are the scattering coefficients on the other measurement port side. .

In order to identify the error factor, it is necessary to perform measurement by attaching at least three types of devices (standard devices) with known scattering coefficients to the object measurement surface. Traditionally, open (OPEN), short circuit (SHORT), and termination (LOAD = 50Ω) are often used, and such a standard device can be realized in a coaxial environment, so this method is widely used. , Called SOLT correction. In the SOLT correction, as shown in FIG. 3, three types of connectors 4 of a short circuit (0Ω), an open circuit (∞Ω), and a termination (50Ω) are used, and the ports are directly connected to form a through state. .

However, in the case of SOLT correction, it is extremely difficult to realize such a standard device except in a coaxial environment, and the standard device necessary for correction cannot be realized in a chip device shape. For example, unlike a waveguide or a coaxial transmission line, a flat transmission line used when measuring surface-mount components cannot obtain good “open” or “termination”, and actually performs SOLT correction. Can not do it. In general, the measurement value obtained by the measurement is not the subject 1 itself but a characteristic obtained by synthesizing the subject 1 and the measurement jig 2 to which the subject is connected, and the characteristics of the subject alone can be measured. Can not.

As shown in FIG. 4, the TRL correction means that the transmission line 5a in the directly connected state (Through), the transmission line 5b in total reflection (Reflection = normal short circuit), Several types of transmission lines (Lines) 5c and 5d having different lengths are used as standard devices. The transmission lines 5a to 5d can be easily manufactured with a comparatively known scattering coefficient, and if the total reflection is short-circuited, its characteristics can be predicted relatively easily. It is. Therefore, in principle, the characteristics of the subject 1 alone can be measured.
In this example, the through transmission line 5a is a so-called zero-through. At the time of measuring the subject, the subject is connected in series to the measuring jig 2 that is longer than the through transmission path 5a by the size of the subject.

However, when the TRL correction is applied to the surface mount device that is the subject, the following problems occur.
1) In transmission lines (several types of lines, reflection and through) 5a to 5d, which are standard devices, all error factors generated in the connection portion between the coaxial connector 3 and the transmission lines 5a to 5d must be equal. However, even if the same type of connector is used for each standard device, the characteristic variation becomes extremely large when connecting each standard device to the measuring instrument, causing a correction error, which is practically performed when approaching the millimeter wave band. It becomes impossible.
2) In order to solve the above-mentioned problem, there has been an effort to avoid the influence of variations in connector measurement by using the coaxial connector 3 in common and connecting the coaxial pins to a standard transmission line. However, it is difficult to secure a sufficient pressing load on the contact portion due to the structure such as the coaxial pin being damaged, and the correction is often unstable because the contact is not stable. In addition, when the measurement frequency is increased, the transmission path and the coaxial pin are generally narrowed, so that the measurement variation due to the positioning reproducibility increases.
3) Since it is difficult to determine whether the measurement at the time of correction is normal or not during the correction work, the contact failure at the time of the correction, etc. is not made until the subject is actually measured after the time-consuming correction work. The waste of noticing the accident.

Patent Document 1 discloses a method for calibrating a network analyzer having two test terminals connected to a subject via a strip line. That is, in the first calibration measurement, transmission and reflection parameters are measured on a strip line connected in a non-reflective manner between the two test terminals on a line whose propagation constant is unknown, and the same line is measured. In use, three additional calibration measurements are performed with three calibration standards implemented by reflection-symmetric and reciprocal discontinuities inserted at three different locations on the line.
That is, by changing the state of the transmission path to three states, three types of standard devices are realized, and the standard devices are connected only once. If this method is used, the number of connections of the standard device can be reduced as compared with the TRL correction, and the measurement error in the calibration operation can be reduced.

However, when actually measuring the subject, it is necessary to remove the strip line used as a standard device and reconnect a strip line (jig) to which the subject can be connected. Naturally, the characteristics of the connecting portion when reconnected change, resulting in a measurement error.
Further, it is practically difficult to connect the strip line between the two test terminals in a non-reflective manner, and the reflection coefficient at the connection between the test terminal and the strip line becomes an error factor.
Furthermore, the measurement value obtained by connecting the subject is not only the subject but also a characteristic obtained by synthesizing the subject and the strip line connecting the subject, and the characteristics of the subject alone cannot be measured.
Application Note 1287-9; In-Fixture Measurements Using Vector Network Analyzers ((C) 1999 Hewlett-Packard Company) JP-A-6-34686

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for measuring high-frequency electrical characteristics of an electronic component with high accuracy that is free from the influence of variations in characteristics of connecting portions, while solving problems in TRL correction and SOLT correction.
Another object of the present invention is to provide a high-precision electronic component high-frequency electrical property measuring apparatus.
Another object of the present invention is to provide a highly accurate method for calibrating a high-frequency electrical characteristic measuring apparatus.

In order to achieve the above object, an invention according to claim 1 is a method for measuring high-frequency electrical characteristics of an electronic component, comprising a plurality of signal conductors spaced apart from each other, and at least one ground conductor, Preparing a transmission line with known electrical characteristics per unit length; connecting each of the signal conductors and the ground conductor to a measurement port of a measuring instrument; and at least a length direction of each of the signal conductors Measuring the electrical characteristics by connecting the signal conductor and the ground conductor in three locations, measuring the electrical characteristics by mutually connecting the signal conductors, and the measured values in the connected state; A step of obtaining an error factor of a measurement system including the transmission path from a measurement value in a through state and an electrical characteristic of the transmission path, and between the signal conductors or between the signal conductors; Connecting the measured electronic component between the ground conductor and measuring the electrical characteristics; removing the error factor of the measurement system from the measured value of the measured electronic component; and measuring the electrical characteristics of the measured electronic component And a step of obtaining a true value. A method for measuring high-frequency electrical characteristics of an electronic component is provided.

In the present invention, a subject is connected in series between a signal conductor and a ground conductor of a transmission line, which is a measurement jig, or connected between signal conductors and a ground conductor, and its reflection and transmission coefficients, etc. Is a method for removing errors in the transmission line and other measurement systems in the method of measuring the electrical characteristics and obtaining the electrical characteristics such as the impedance value and the quality factor. The present invention has been made based on the knowledge that when a measurement system error is measured, a short-circuit state of a transmission line can be easily realized with a good quality.
In a preferred example of the correction method according to the present invention (hereinafter referred to as RRRR calibration), a short circuit reference is used as a calibration reference (standard device). This is almost totally reflected in the short circuit state, so it is not affected by the terminal end of the signal conductor, and in the frequency range where the target transmission line operates in the TEM single mode, the characteristics of the short circuit state are obtained. This is because there is substantially no influence of the dielectric, and its electric characteristics can be predicted with high accuracy by electromagnetic field simulation.
In general, the dielectric constant is the parameter that limits the accuracy of transmission line characteristics when simulating, but it is confirmed that there is almost no change in the calculation result even if the dielectric constant is changed in the short-circuit reflection characteristics. Therefore, it can be said that the simulation result is assumed to be a physical true value and can be used for calibration. When the width of the transmission line is sufficiently smaller than the wavelength of the measurement signal, it is considered that a large error does not occur even when -1 (reflection coefficient of an ideal short circuit) is used as the short circuit characteristic.

Here, an outline of the RRRR calibration according to the present invention will be described.
Calibration process 1: Measurement in short-circuit state In RRRR calibration, the transmission line is short-circuited in at least three locations on the transmission line having a plurality of signal conductors having uniform electrical characteristics in the length direction, thereby measuring the measurement system. Identify error factors. In order to achieve a short circuit state, for example, a short circuit reference is connected between the signal conductor and the ground conductor. Specifically, measurement is performed with a short-circuit reference connected to the subject measurement position on the transmission line, and then measurement is performed with the short-circuit reference connected to a point separated by L ₁ from the subject measurement position. A measurement is performed with a short-circuit reference connected to a point separated by L ₂ from the measurement position. If the transmission line characteristics are unknown, it is necessary to measure at a different point.
Here, the short-circuit standard refers to general components in an electrical short-circuit state, and is not limited to a chip component, and may be a metal piece or a tool. Desirably, the contact length in the longitudinal direction of the transmission path such as a knife edge is short. If the short-circuit standard is ideal, the reflection coefficient will be -1 (total reflection). However, even though the short-circuit standard actually has some inductance, the inductance value needs to be known. It is. Usually, in the microwave band, a short state can be obtained relatively easily in an ideal state compared to an open state. When high measurement accuracy is required, the short-circuited reference inductance may be obtained by simple simulation or the like.
Calibration step 2: Measurement in the through state Separately from the measurement in the short circuit state, the signal conductors are mutually brought into the through state to identify the error factors of the measurement system. In order to obtain the through state, for example, through chips having no directivity in the transmission coefficient are connected in series. In the RRRR calibration that can be measured by the series method, it is necessary to make a through connection between the ports. At this time, the characteristics of the through chip may not be known, and for example, a chip resistor having an unknown resistance value may be used, but there should be no directivity. It is assumed that devices that have directionality in signal transmission cannot be made (reciprocity theorem), except for isolators, circulators (special elements that use magnetic materials under a DC magnetic field), or active elements such as semiconductor amplifiers. Is virtually automatically charged. The through chip is not limited to a chip component, and may be any component as long as it has no directivity in signal transmission.
Actual measurement step: The electronic components to be measured are connected in series between the signal conductors of the measurement transmission path of the subject, or both the series connection and the connection with the ground conductor are performed simultaneously to measure the electrical characteristics.
Using the measured electrical characteristics of the subject and the error factors obtained in the calibration steps 1 and 2, the true value of the electrical characteristics of the subject can be obtained by calculation.
In particular, if measurement in a short-circuit state is performed at four or more locations, the electrical characteristics of the transmission line can be obtained in addition to the error factors of the measurement system.

In the above description, the signal conductor and the ground conductor are short-circuited in the calibration step. However, it is not always necessary to short-circuit, and the signal conductor and the ground conductor may be connected so as to obtain some reflection state.
When a calibration standard with a transfer coefficient such as chip resistance is used instead of the short circuit standard, a part of the signal input from one port passes through the contact with the calibration standard, and the open end of the signal conductor Since it returns after being totally reflected, there is a possibility of measurement errors. However, assuming that, for example, 16% (−16 dB) of the input signal passes through the contact with the calibration reference and is transmitted to the open end of the signal conductor, where it is totally reflected, about −32 db (= − 16 × 2), and the error level is about 2.5% of the input signal. Therefore, if the signal flowing to the open end is about 16% or less of the input signal, the error is very small and the accuracy required for calibration can be obtained.
On the other hand, if a signal larger than 16% passes through the contact portion with the calibration reference, there is a possibility that the error becomes large. Connect it with a chip. Since the signal is transmitted to the port 2 side through the through chip and is not totally reflected at the open end of the signal conductor, the signal level returned can be lowered.

The present RRRR calibration method implemented as described above has the following characteristics.
(1) Correction and measurement are all performed on the same transmission line.
In TRL correction, transmission lines of several lengths are necessary as standard devices, and all of the electrical characteristics of the connection portion between these and the coaxial cable need to be equal. Since all the same transmission lines are used, there is no need to change the transmission lines, and there is no influence of variations in characteristics such as transmission lines, connectors, and connection parts.
(2) The measurement of the two-terminal element series method as well as the measurement of ordinary electronic components having two or more ports (electronic components having three or more terminals) can be performed without any problem, and the measurement target is not selected. In particular, the measurement accuracy of electronic components having an impedance higher than the characteristic impedance of the transmission line is high.
(3) The length of the transmission line required for the measurement jig is determined by the lower limit of the frequency to be measured. A long transmission line is required to cope with a low frequency, but a short transmission line is sufficient to cope with a high frequency.
(4) Measurement for correction is performed by performing measurement based on a calibration standard (for example, short circuit standard) at several points on the transmission line and through measurement using an appropriate device.
How far away from the measurement position of the subject how many calibration standards should be measured is determined by the measurement frequency bandwidth and the upper frequency limit. Further, the scattering coefficient of the through chip may be unknown as long as it does not have directivity.
(5) If the measurement based on the calibration standard is performed at four or more locations on the transmission line, the characteristics of the transmission line can also be known.
If the characteristics of the transmission line are known, the error factor of the measurement system can be obtained by connecting the calibration reference at three locations, but if the calibration reference is connected at four or more locations, the error factor of the measurement system can be obtained. As well as the characteristics of the transmission line itself (dielectric constant, loss factor, etc.) can be obtained. Therefore, even if the dielectric constant and loss factor of the dielectric material used in the transmission path jig are unknown or the dielectric material has characteristic variations from lot to lot, the characteristics of the transmission path jig itself used Can be obtained accurately, and high-precision calibration without error becomes possible.
In general, a transmission line jig made of a base material such as Teflon (registered trademark) or alumina has little variation in electrical characteristics, and its physical true value can be easily obtained, but is expensive. On the other hand, a transmission line jig made of a base material made of a general-purpose resin such as an epoxy resin is inexpensive, but has a large variation in material characteristics, and a variation in dielectric constant and loss coefficient. In such a case, if the transmission path characteristics are obtained by connecting calibration standards at four or more locations, the electrical characteristics of the subject can be measured with high accuracy without being affected by variations in the transmission path characteristics.
(6) When impedance measurement is performed, the characteristic impedance and the like of the transmission path need to be known.
If only the scattering coefficient measurement based on the characteristic impedance of the transmission line is required, the characteristic impedance of the transmission line may be unknown. However, if the impedance measurement is desired, the characteristic impedance of the transmission line is known. There is a need. For this purpose, a value calculated by simulation or measured by a time domain reflectometry method may be used.

In the above description, in addition to the measurement result in the short-circuit state, the error coefficient is determined using the measurement result obtained by connecting a series of through-chips with no directivity in the transfer coefficient. The subject can also be regarded as a kind of through chip. Therefore, it is possible to omit the measurement using the through chip and determine the error coefficient using the measurement result of the subject and the measurement result in the short circuit state.
In this case, the subject is not limited to two terminals, and an electronic component having three or more terminals can be applied as long as there is no direction between the ports.

By connecting an appropriate through chip to the object measurement location at the time of the short-circuit reference measurement, it is possible to detect a short-circuit reference contact failure with the magnitude of the transmission coefficient. That is, when contact failure occurs for some reason, the contact failure can be detected by increasing the transmission coefficient between the ports. In this way, since a measurement error can be detected during the correction procedure, it is possible to prevent waste that would prove that the correction failed when the subject was measured later.

In the above correction, the error factor up to the subject measurement position can be removed, but the error between the subject measurement positions, for example, the error factor between the contact points of the subject electrode of each port is not considered in the case of two ports. The largest of these errors is stray capacitance that exists between signal conductors. If there is stray capacitance, when the subject is measured, a value including the stray capacitance is measured, which causes an error.
Therefore, by measuring the electrical characteristics of the signal conductor that is not connected to anything (open state), obtaining the floating admittance from the measurement result, and mathematically removing the effect of the floating admittance from the measurement result of the subject, the floating capacitance Error can be eliminated, and more accurate characteristic measurement becomes possible.

In order to short-circuit the signal conductor and grounding conductor of the transmission line, the short-circuit reference is connected to the transmission line, but the effect of the residual inductance of the short-circuit reference is large due to the high frequency, and it is not close enough to the short-circuit (port Signal may pass between them and total reflection may not be obtained).
In this case, it is preferable that the calibration reference is brought close to (not in contact with) the transmission line, and the stray capacitance generated between the transmission line and the calibration reference and the residual inductance of the calibration reference are in a series resonance state.
In the series resonance state, the impedance of the calibration reference connection portion is 0Ω, that is, an ideal short-circuit state. That is, even at a high frequency where a good short-circuit standard cannot be obtained, the same effect as that obtained by using a good short-circuit standard can be obtained.
When a capacitor with a very small capacity is used as a calibration standard, the capacitor can be brought into contact (completely connected) with the transmission line to cause series resonance.

As the transmission line of the present invention, it is preferable to use a transmission line in which a signal conductor and a ground conductor are formed on the same plane. This is because it is easy to connect the calibration reference and the subject to the signal conductor and the ground conductor simultaneously in the correction work using the calibration reference and the measurement work using the subject. In addition, since the calibration reference and the subject can be pressed perpendicularly to the transmission path during the correction measurement, it is easy to secure a sufficient pressing load and the contact is easily stabilized.
As a specific transmission line, a coplanar wave guide or a slot line can be used. The coplanar wave guide has a signal conductor and a ground conductor on both sides of the signal conductor. The signal conductor and the ground conductor are formed on the same plane. For measuring high frequency characteristics up to 10 GHz. Is suitable.
On the other hand, in the slot line, a signal conductor and a ground conductor are provided on the same plane with a space therebetween, and is suitable for measurement of high frequency characteristics of 10 GHz or more.

The position where the calibration reference is connected is preferably a position where the phase difference between the positions is 70 ° to 145 °.
In order to perform correction with high accuracy, it is desirable that the correction data is as far as possible from each other. In the RRRR calibration in which correction data that differs depending on the reflection phase of the calibration reference is obtained, the connection between the calibration reference connection positions necessary for the correction A phase difference of 70 ° to 145 ° is desirable for improving calibration accuracy. However, if the phase difference between the connection positions is set as described above, the calibration accuracy is high, but the frequency range that can be handled by one set of calibration standards is considerably narrowed. However, if the calibration reference connection position is set very easily and the measurement data at the time of calibration is used well, the number of calibration reference measurements will not increase to a practical level even for wideband measurements.

It is a figure which shows the error model of the measurement system and SOLT correction | amendment using the conventional network analyzer. It is a figure which shows the error model of the measurement system and TRL correction | amendment using the conventional network analyzer. It is a figure which shows a SOLT calibration method. It is a figure which shows the TRL calibration method. It is a top view of the high frequency electrical property measuring apparatus which shows an example of the RRRR calibration method concerning this invention. It is a front view of the high frequency electrical property measuring apparatus at the time of calibration shown in FIG. It is a top view of the high frequency electrical property measuring apparatus in the through measurement concerning the present invention. It is an error model figure used with the RRRR calibration method concerning this invention. It is a top view at the time of the subject measurement of the high frequency electrical property measuring device concerning the present invention. It is a flowchart figure of an example of the RRRR calibration method concerning this invention. It is a flowchart figure of the other example of the RRRR calibration method concerning this invention. It is a figure which shows the influence of the stray capacitance which generate | occur | produces between transmission lines. It is a high frequency characteristic figure of a chip inductor measured using RRRR calibration method concerning the present invention. It is a top view of the high frequency electrical property measuring apparatus which shows the other example of the RRRR calibration method concerning this invention. It is a figure which shows the example which carries out a series resonance between a calibration reference | standard and a transmission line. It is a top view which shows the example of the transmission line which has 3 ports. It is a top view of the example which used the slot line as a transmission line.

Hereinafter, RRRR calibration according to the present invention will be described in detail with reference to examples.

5 to 9 show a first embodiment according to the present invention.
-Calibration standard for RRRR calibration-
In the RRRR calibration, the calibration standards to be measured are all the same short-circuit standard 10, and the measurement jig 11 (transmission path 12) to be used is also the same jig.
As shown in FIG. 5, the measurement is performed at three or more locations on the transmission line 12 formed in the measurement jig 11. Although the correction on the port 1 (connector 11a) side will be described here, the same operation is required on the port 2 (connector 11b) side.

Here, a coplanar wave guide will be described as an example of the measuring jig 11. As shown in FIGS. 5 and 6, the measurement jig 11 has two signal conductors 12 a and 12 b arranged on a straight line on the upper surface of the jig substrate 11 c with one end being spaced and the other end being a connector 11 a, 11b, respectively. Ground conductors 12c are arranged on both sides in the width direction of the signal conductors 12a and 12b, and the signal conductors 12a and 12b and the ground conductor 12c are formed on the same plane on the jig substrate 11c. In this jig substrate 11a, a ground conductor 12d is also formed on the back surface. A coaxial cable 14 is connected to each of the connectors 11a and 11b, and is connected to measurement ports 21 to 24 of a network analyzer 20 which is an example of a measuring instrument. The signal line 14a of the coaxial cable 14 is fixed to the signal conductors 12a and 12b by soldering or welding in order to eliminate connection variation. The measurement ports 21 and 24 are connected to the signal conductors 12a and 12b via the coaxial cable 14, and the measurement ports 22 and 23 are connected to the ground conductor 12b.

As shown in FIG. 6, a pusher 15 that presses the short-circuit reference 10 against the transmission path 12 and a mechanism 16 that can freely move the pusher 15 along the transmission path 12 are provided above the measurement jig 11. Here, a knife-edge conductor attached to the tip of the insulating pusher 15 was used as the short-circuit reference 10.

-Connection and measurement of short circuit reference-
First, measurement is performed by connecting the short-circuit reference 10 to a location (measurement point 1: P1 in FIG. 5, hereinafter referred to as “subject measurement location”) where one electrode is connected during measurement of the subject. The result is _S11M1 . At this time, the true value of the reflection coefficient at the measurement location is Γ _A1 . Γ _A1 is a true value of the short-circuit reference, and this may be −1 if the length in the length direction of the transmission line 12 of the short-circuit reference 10 is sufficiently smaller than the measurement signal wavelength. For example, the expected value of the true value should be obtained by simulation or the like.

Then, the position of the signal conductors 12a at a distance L ₁ to the port 1 side of the analyte measurement points (measurement point 2: P2) was measured by connecting a short circuit reference 10, the measurement results of the S _11M2 And At this time, the true value of the reflection coefficient of the short-circuit reference 10 at the measurement point 2 is of course Γ _A1 , but when the object measurement location is taken as the reference plane, the true value of the reflection coefficient is converted as shown in Equation 1. This is because the electromagnetic wave incident from the port 1 side is totally reflected by the short-circuit reference 10, and therefore the distance for transmitting the transmission path by 2L ₁ for the round trip is shorter than when the short-circuit reference 10 is connected to the subject measurement location. . Where α is the transmission rate [U / mm] of the transmission line per unit length, β is the phase constant [rad / mm] of the transmission line, and Γ _A2 is the value when the subject measurement point is the reference plane The true value of the short-circuit reference 10 connected to the measurement point 2.

Subsequently, the position of the signal conductors 12a in port 1 side of the analyte measurement points separated by L ₂ (measurement point 3: P3) was measured by connecting a short circuit reference 10, the measurement results of the S _11M3 And As in the case of the measurement point 2, when the subject measurement point is taken as the reference plane, the true value of the reflection coefficient is expressed by Equation 2.

It should be noted that Γ _A2 and Γ _A3 may exceed 1 as apparent from the fact that Equations 1 and 2 are negative power of the transmission path. Normally, there cannot be a short circuit reference having a reflection coefficient larger than 1, but this is caused by the fact that Equation 1 and Equation 2 take the reference plane as the object measurement location. It is not abnormal.

Characteristics of the transmission path alpha, when β is unknown, further position of apart transmission line distance L ₃ from the measuring point 1 to the port 1 side (measurement point 4: P4) to the measurement by connecting the short circuit reference 10 The measurement result is S _11M4 . When the measurement point 1 is taken as the reference plane as in the case of the measurement point 2, the true value Γ _A4 of the reflection coefficient at the measurement point 4 is expressed by Equation 3.

Here, an expression including α and β is set as ξ as follows. ξ physically represents the transmission coefficient of the transmission line per unit length.

Using Equation 4, Equations 1 to 3 can be rewritten as Equations 5 to 7, respectively.

As described above, when the transmission line characteristic ξ is unknown, not only the error coefficient but also the transmission line characteristic ξ can be obtained by short-circuiting the short-circuit reference at four locations of the transmission line.
The transmission line characteristic ξ includes two unknowns, a transmission factor α and a phase coefficient β, but the transmission line characteristic ξ is a complex number whose real part is related to the transmission degree α and whose imaginary part is related to the phase coefficient β. From this, it can be obtained as one unknown.
For convenience of later calculations, it is desirable that the distances L ₁ , L ₂ , L ₃ from the subject measurement position for measuring the short-circuit reference satisfy one of the following relationships.
L ₁ : L ₂ : L ₃ = 1: 2: 3
L ₁ : L ₂ : L ₃ = 1: 2: 4
If the relationship is satisfied, the transmission path characteristic can be calculated explicitly using the following mathematical formula. If the above relationship is not satisfied, the transmission path characteristics cannot be calculated by the following formula, so it is necessary to obtain it by iterative calculation or the like.

When the positions L ₁ , L ₂ , and L ₃ for measuring the short-circuit reference satisfy the relationship of L ₁ : L ₂ : L ₃ = 1: 2: 3, ξ can be obtained by Expression 8.

Ｌ₁ ：Ｌ₂ ：Ｌ₃ の比が前記の条件を満たさない場合については、ξを求める式を陽に導いていないので、必要に応じて同様の式を誘導しておくか、あるいは反復計算によってξを求めるかすれば良い。On the other hand, when the relationship of L ₁ : L ₂ : L ₃ = 1: 2: 4 is satisfied, ξ can be obtained by Equation 9.

In the case where the ratio of L ₁ : L ₂ : L ₃ does not satisfy the above condition, the formula for obtaining ξ is not derived explicitly, so a similar formula is derived as necessary or iterative calculation is performed. It is sufficient to obtain ξ by

If ξ is obtained by Equation 8 or Equation 9, the values of Γ _A2 and Γ _A3 can be calculated by Equation 5 and Equation 6, so that error coefficients described later can be obtained sequentially.

-Through-chip connection and measurement-
Next, as shown in FIG. 7, measurement is performed in a through (direct connection between ports) state. An appropriate device (hereinafter referred to as a through chip) 13 for connecting the ports is connected in series between the signal conductors 12a and 12b. Measurements, reflection coefficient S _11MT, in S _22MT, the transfer coefficient and S _21MT, S _12MT. As will be described later, the electrical characteristics of the through chip 13 may be unknown. For example, a chip resistance whose resistance value is unknown may be used, but the transmission coefficient should not have directionality. This condition is usually satisfied automatically because the transfer coefficient does not have directionality according to the reciprocity theorem unless a special material such as ferrite under a DC magnetic field is used.

-Calculation of error coefficient of error model for RRRR calibration-
An error model for RRRR calibration is shown in FIG. This is not particularly novel, and is the same as the error model for TRL correction that has been conventionally used. In the figure, S _11M and S _21M are measured values of the reflection coefficient and the transmission coefficient, and S _11A and S _{21A and the} like are true values of the scattering coefficient of the object. Further, although there are eight error coefficients E _xx and F _xx , the scattering coefficient measurement is a ratio measurement, and therefore, seven error factors may be determined. Specifically, E ₂₁ = 1 may be set.

Now, it is necessary to obtain each error coefficient in FIG. 8 from the measurement result obtained by connecting the short-circuit reference 10 described above. First, E ₁₁ , (E ₁₂ · E ₂₂ ) , F ₁₁ , (F ₂₁ · F ₁₂ ) , F ₂₂ is obtained by the following equation. Incidentally, F _xx are same as E _xx, described only E _xx. At this stage, for ( E ₂₁ · E ₁₂ ), the product of the two error coefficients E ₂₁ and E ₁₂ is obtained, but these cannot be obtained independently. D ₁ is an intermediate variable.

Next, the measurement results S _21MT and S _12MT of the forward and reverse transfer coefficients of the through chip can be written as follows using the error factors of FIG. However, the true value of the through-chip scattering coefficient is assumed to be S _11A , S _21A , S _12A , S _22A .

Here, the ratio of S _21MT and S _12MT is considered. Based on Equation 11, the following equation can be obtained by arranging the transmission coefficients in the forward and reverse directions of the through chip with equality (S _21A = S _12A ). It should be noted here that the through-chip scattering coefficients S _11A , S _21A , S _12A , and S _22A are all eliminated by division. In other words, even if the true value of the scattering coefficient of the through chip is unknown, if the through chip has no directionality, if the ratio of S _21MT and S _12MT (this is a measurable amount) is known, the relationship of the error coefficient is It is to be decided.

Based on Equation 10 and Equation 12, the total error coefficient can be determined as follows:

With the above, all error coefficients could be determined. The above is a discussion when a signal is applied from the port 1 side to the port 2 side (forward direction), but the reverse direction can be derived by setting F ₂₁ = 1 instead of E ₂₁ = 1.

-Measurement of subject and implementation of RRRR calibration-
When the error coefficient is obtained, the subject 17 is connected to the transmission path 12 and its characteristics are measured. For example, the subject 17 is adsorbed using a chip mounter or the like, and the subject 17 is brought into contact with the subject measurement position of the transmission path 12 to measure the electrical characteristics (S _11M, S _21M, S _12M, S _22M ). . At this time, when the subject 17 has two terminals, the signal conductors 12a and 12b may be connected in series as shown in FIG. 9A. However, when the subject 17 has three terminals or four terminals, FIG. What is necessary is just to connect between signal conductor 12a, 12b and the grounding conductor 12c like (b). Therefore, the measuring method according to the present invention can be applied not only to a two-terminal electronic component but also to an electronic component having three or more terminals such as a filter.

Since the error model for RRRR calibration is the same as the error model for TRL correction, the same calculation as TRL correction may be performed to remove the effect of error from the actual measurement result of the object, and the effect of error is removed. The mathematical formula is described below. In order to eliminate the influence of the error factor, this equation is calculated based on the reflection coefficient in the case of 2-port measurement, but may be calculated from the four receiver outputs of the network analyzer. Also, in the case of three or more ports, the same equation as this equation may be used, or the influence of the error factor may be removed using a circuit simulation method. In short, any known technique may be selected. In Equation 14, D ₂ is an intermediate variable.

FIG. 10 is a flowchart of an example of the RRRR calibration method.
When the correction is started, first, the measuring instrument and the measuring jig are connected via a coaxial cable (step S1). Next, the signal conductor 12a and the ground conductor 12c are short-circuited by the short-circuit reference 10 at the first position that is the open end of one signal conductor 12a (step S2). The first position may be near the subject measurement position, or may be another position. With the short-circuit reference 10 connected, the reflection coefficient (S _11M1 ) on the port 1 side is measured (step S 3).
Next, the signal conductor 12a and the ground conductor 12c are short-circuited by the short-circuit reference 10 at the second position (step S4), and the reflection coefficient (S _11M2 ) on the port 1 side is measured (step S5). Subsequently, the signal conductor 12a and the ground conductor 12c are short-circuited by the short-circuit reference 10 at the third position (step S6), and the reflection coefficient (S _11M3 ) on the port 1 side is measured (step S7). If the transmission line characteristics are unknown, the signal conductor 12a and the ground conductor 12c are further short-circuited by the short-circuit reference 10 at the fourth position (step S8), and the reflection coefficient (S _11M4 ) on the port 1 side is measured ( Step S9). Then, the transmission line characteristic ξ on the port 1 side is obtained by calculation from these reflection coefficients (step S10). If the transmission path characteristics are known, steps S8 to S10 are not necessary.
Next, the signal conductor 12b and the ground conductor 12c are short-circuited by the short-circuit reference 10 at the fifth position which is the open end of the other signal conductor 12b (step S11). The fifth position may be near the subject measurement position or may be another position. With the short-circuit reference 10 connected, the reflection coefficient (S _22M1 ) on the port 2 side is measured (step S12).
Next, the signal conductor 12b and the ground conductor 12c are short-circuited by the short-circuit reference 10 at the sixth position (step S13), and the reflection coefficient (S _22M2 ) on the port 2 side is measured (step S14). Subsequently, the signal conductor 12b and the ground conductor 12c are short-circuited by the short-circuit reference 10 at the seventh position (step S15), and the reflection coefficient (S _22M3 ) on the port 2 side is measured (step S16). If the transmission line characteristics are unknown, the signal conductor 12b and the ground conductor 12c are further short-circuited by the short-circuit reference 10 at the eighth position (step S17), and the reflection coefficient (S _22M4 ) on the port 2 side is measured (step S17). Step S18). Then, the transmission path characteristic ξ on the port 2 side is obtained by calculation from these reflection coefficients (step S19). If the transmission path characteristics are known, steps S17 to S19 are not necessary.
Next, the through chip 13 is connected in series between the signal conductors 12a and 12b (step S20), and the transmission coefficients (S _21MT, S _12MT ) are measured (step S21).
Thereafter, using the measured reflection coefficient, transmission coefficient, and transmission path characteristic ξ, an error coefficient is calculated by Expressions 10 to 13 (step S22).
After calculating the error coefficient, and connect the subject to the measurement jig (Step S23), the reflection coefficient and transmission coefficient of the forward and backward direction of the subject _{(S 11M, S 21M, S} 12M, S 22M) measured (Step S24). Next, the influence of the error is removed from the measured value by Equation 14 (step S25), and the error removal result (the true value of the subject) is displayed on the display, the subject is selected, etc. (step S26). Thereafter, steps S23 to S26 are repeated until the measurement of all the objects is completed (step S27). When the measurement of all the objects is completed, the RRRR calibration is terminated.

If a contact failure occurs between the short-circuit reference 10 and the transmission line 12 when the short-circuit reference 10 is connected, the measured reflection coefficient becomes an incorrect value. If the measurement is performed without knowing the contact failure, waste that causes a correction failure at the time when the subject is measured later occurs.
FIG. 11 is obtained by adding a step of detecting a contact failure from the transmission coefficient in the error coefficient derivation process of FIG. Here, only contact failure detection at the first position is shown, but the same applies to other positions.
First, the measuring instrument and the measurement jig are connected via a coaxial cable (step S1), and the signal conductor 12a and the ground conductor 12c are short-circuited by the short-circuit reference 10 at the first position (step S2). The chip 13 is connected between the signal conductors 12a and 12b (step S30). With the short-circuit reference 10 and the through chip 13 connected at the same time, the reflection coefficient (S _11M1 ) and the transmission coefficient (S _21M1 ) on the port 1 side are measured (step S31), and the measured transmission coefficient is sufficiently small. If it is not sufficiently small, it is determined that the contact is defective, and step S2 and subsequent steps are repeated again. On the other hand, when the transmission coefficient is sufficiently small, it is determined that the contact is good, and the measurement at the next second position is started.
As described above, since the total reflection occurs when the short-circuit reference 10 is in normal contact, the transmission coefficient between the jig ports is very small. However, the contact failure between the short-circuit reference 10 and the transmission path 12 is poor. If this occurs, the transfer coefficient between ports increases. By utilizing this difference in transmission coefficient, it is possible to easily determine a contact failure.
In this way, since a measurement error can be detected during the correction procedure, it is possible to prevent waste that would prove that the correction failed when the subject was measured later.

Here, how to select the measurement position of the short-circuit reference 10 will be described.
It is assumed that the short-circuit reference 10 is measured at the object measurement location on the transmission line 12 and at a point 5 mm away from the object measurement location. If the loss of the transmission line 12 is not large, the difference between the two measurement results is only the phase. Here, it is assumed that the wavelength is 30 mm (the wavelength of an electromagnetic wave of 1 GHz in a vacuum). Since the difference in the 5 mm position corresponds to the difference in the 10 mm position in the reciprocation, the measurement data can be expected to have a phase difference of (10 mm ÷ 30 mm) × 360 ° = 120 °. However, if the wavelength is 10 mm (wavelength of 3 GHz electromagnetic wave in vacuum), the phase difference produced by the difference in the position of 10 mm in the reciprocation is 10 mm ÷ 10 mm × 360 ° = 360 °. Does not occur. For this reason, if the position is 5 mm, correction cannot be normally performed at a frequency of 10 mm.

In order to perform correction with high accuracy, it is desirable that the correction data is as far as possible from each other. In RRRR calibration in which correction data that differs depending on the phase of reflection of the short circuit reference is obtained, the phase difference between the connection positions of the short circuit reference is 70. It is preferable to adopt the condition of ° to 145 °.
If a large phase difference between the calibration standards is secured, the accuracy of calibration is improved, but the frequency range that can be handled by a set of calibration standards is narrowed, and it is necessary to measure many calibration standards when performing a broadband measurement. In the case of TRL calibration in which calibration is performed using the phase difference between calibration standards as in RRRR calibration, the phase difference between calibration standards should be secured to about 20 ° to 30 ° or more in order to obtain good measurement accuracy. ing.
On the other hand, when the phase difference between the connection positions of the short-circuit reference is set to 70 ° to 145 °, the calibration accuracy is high, but the frequency range that can be handled by one set of calibration reference is considerably narrower than the above case. . However, as described below, the setting of the short-circuit reference connection position is very simple, and if the measurement data at the time of calibration is used well, even if it is a wideband measurement, the number of short-circuit reference measurements is such that it becomes a practical problem. This is because there is no increase.

次に、第３の短絡基準測定位置を２Ｌ[mm]に、第４の短絡基準測定位置を４Ｌ[mm]に設定する。同様に、第ｎの短絡基準測定位置を２^n-2 Ｌ[mm]に設定する。
測定上限周波数ｆ_max からｆ_max ／２までの周波数帯は、第１、第２、第３の短絡基準測定位置の測定結果によってＲＲＲＲ校正を行う。ｆ_max ／２〜ｆ_max ／４までの周波数帯は、第１、第３、第４の短絡基準測定位置の測定結果を用いる。同様に、ｎ番目の周波数帯、すなわちｆ_max ／２^n-1 〜ｆ_max ／２ⁿ の周波数帯は、第１、第ｎ＋１、第ｎ＋２の短絡基準測定位置の測定結果を用いる。このようにすることで、概ね短絡基準測定位置間の位相差が７０°〜１４５°の範囲に保たれる。First, a second short-circuit reference measurement position where the phase is about 145 ° at the measurement upper limit frequency is obtained. Specifically, β [rad / mm] may be obtained by the following equation using a phase constant and L [mm] as a short-circuit reference measurement position.

Next, the third short-circuit reference measurement position is set to 2 L [mm], and the fourth short-circuit reference measurement position is set to 4 L [mm]. Similarly, the nth short-circuit reference measurement position is set to 2 ⁿ⁻² L [mm].
In the frequency band from the measurement upper limit frequency f _max to f _max / 2, RRRR calibration is performed based on the measurement results at the first, second, and third short-circuit reference measurement positions. frequency band up to f _max / 2~f _max / 4, the first, third, using the measurement results of the fourth short circuit reference measurement position. Similarly, the measurement results of the first, n + 1, and n + 2 short-circuit reference measurement positions are used for the nth frequency band, that is, the frequency band of f _max / 2 ^{n−1 to} f _max / 2 ⁿ . By doing in this way, the phase difference between short circuit standard measurement positions is generally maintained in the range of 70 ° to 145 °.

-Open correction-
In the RRRR calibration, the error factor up to the subject measurement position can be removed, but the error factor between the subject measurement positions, for example, in the case of two ports, the error factor between the contact points of the subject electrode of each port is not considered. The largest of such errors is the stray capacitance between the ports (stray capacitance Cs between the signal conductors 12a and 12b) as shown in FIG. In other words, the signal transmitted through the TEM through the coplanar waveguide is reflected by the high-impedance subject 17 and reflected, but there is an error factor that part of the signal is transmitted as a TM wave. The series method to which the RRRR method belongs should be able to cope with high impedance measurement if a high-isolation measuring jig is used. However, a jig made of a material having a high dielectric constant such as a glass epoxy material may be used. Alternatively, if a jig having a thickness as thick as 1.6 mm, for example, is used, the stray capacitance between the ports increases and the isolation decreases. If a thin jig is made of a material having a low dielectric constant such as Teflon (registered trademark), this problem is reduced. However, if this is not enough, or if you cannot use a jig with satisfactory characteristics due to problems such as cost (Teflon (registered trademark) substrate is generally expensive), this error is corrected mathematically. it can.
That is, the floating admittance of the measurement result is obtained from the measurement result of the measurement jig alone (open state), and the influence of the floating admittance is mathematically removed from the measurement result of the object. Assuming that Z _C is the impedance obtained by RRRR calibration of the measurement jig alone and Z _M is the impedance obtained by RRRR calibration of the subject measurement result, impedance Z _L after the mathematical processing (open correction) Is obtained by the following equation. If Z _C is too large, the dynamic range of the measurement system will be narrowed, and problems such as increased measurement variation may occur. Therefore, jigs with too low isolation should not be used. Sufficient results can be obtained by processing.

The explanation of the RRRR method has been discussed mainly with the scattering coefficient, but the open correction is discussed with the impedance. The impedance and the scattering coefficient are physical quantities that can be converted to each other. If the characteristic impedance of the transmission path is Z ₀ , the reflection coefficient of the scattering coefficient is S ₁₁ , and the transmission coefficient is S ₂₁ , the scattering coefficient and the impedance Z can be converted by the following equation. Although two equations are listed, the same result is obtained in principle regardless of which equation is used.

-Measurement results-
Using the above RRRR calibration and open correction, FIG. 13 shows the result of measuring a 1 mm × 0.5 mm size 10 nH chip inductor (winding type chip inductor) in the range of 100 MHz to 20 GHz.
As can be seen from FIG. 13, a general impedance characteristic curve of the inductor is obtained. That is, the impedance increases in proportion to the frequency increase up to the self-resonance frequency, and the impedance decreases in inverse proportion to the frequency increase after the self-resonance frequency. Further, a result of almost tracing is also obtained in the measurement by the TRL calibration method which is a conventional technique.
As described above, it was confirmed that the true value of the subject can be measured by the RRRR calibration.

-Error correction method without using through-chip-
In the first embodiment, through chips 13 having no directivity are connected in series between the signal conductors 12a and 12b, the forward and reverse transmission coefficients S _21MT and S _12MT are measured, and the ratio S _21MT / S _12MT is determined. Although the relationship between the error coefficients is determined by determining the ratio, if the subject does not have directionality, it is possible to omit the through-chip measurement and determine the error coefficient using the measurement result of the subject. .
For example, in most subjects such as filters, couplers, baluns, capacitors, resistors, and coils, the subject has no directionality, so the subject can also be regarded as a kind of through chip. If the transmission coefficient ratio S _21M / S _12M is obtained from the measurement result of the subject and this ratio is used in place of S _21MT / S _12MT , the relationship between the error coefficients can be determined from Equation 12.

-Calibration method using calibration standard other than short circuit standard-
In the RRRR calibration, when the calibration reference 18 having a transfer coefficient such as a chip resistance is used instead of the short-circuit reference 10, a part of the signal input from one port passes through the contact portion with the calibration reference, Since it is totally reflected at the open end of the signal conductor and returns, there is a possibility of a measurement error.
In this case, as shown in FIG. 14, the open end of the signal conductor 12 a and the open end of the signal conductor 12 b are connected by the through chip 19, and in this state, the calibration reference 18 is connected to at least 3 of the transmission line 12. What is necessary is just to connect to a place and to perform RRRR calibration. The through chip 19 may be a component similar to the through chip 13 in the through measurement (see FIG. 7), or may be a short chip such as the short-circuit reference 10.
Even if a part of the signal passes through the contact portion between the calibration reference 18 and the signal conductor 12a, the signal is transmitted to the port 2 side through the through chip 19, and the signal is absorbed on the port 2 side to be port 1 side. The signal level returning to can be lowered. For example, when the reflection level at the port 2 is normally expected to be −15 dB to −25 dB and the average is −20 dB, 50% (−6 dB) of the input signal passes through the contact portion with the calibration standard. Even if it is transmitted to the port 2 side, it is about −32 db (= −6−20−6) in the round trip, and the error level is about 2.5% of the input signal.
Therefore, even if the calibration standard 18 having a transfer coefficient is used, high calibration accuracy can be ensured.

If the RRRR calibration is performed alone, the error of the entire measurement system can be corrected. On the other hand, when the RRRR calibration is performed after correcting up to the coaxial connector to which the jig substrate is connected by a technique such as SOLT correction, the obtained error coefficient becomes the error coefficient of the jig substrate. That is, RRRR calibration can be used as a method for identifying an error factor of a jig.
A recent network analyzer has a function (de-embedding function) that automatically removes the influence of an error given from a measurement result if an error coefficient such as a jig is given. However, since there is no method for obtaining the error of the jig, it is a function that is not often used in practice. When combined with the RRRR calibration technique of the present invention, this is a very convenient function.
De-embedding is a technique for mathematically removing known error factors, and can be easily implemented using a transmission matrix. The obtained scattering coefficient matrix of the error factor of the jig is converted into a transmission matrix and converted into an inverse matrix, which are ^designated as E ⁻¹ and F ⁻¹ on the port 1 side and the port 2 side, respectively. At this time, an error factor transmission matrix of each port of the jig is EF. Furthermore, let A be the transmission matrix of the device. At this time, the measurement result of measuring the device together with the jig with the network analyzer calibrated to the end of the coaxial cable is that the error of each port is superimposed on the device.
Should have been measured. So if you multiply E ^-1 and F ^-1 from the left and right respectively
E ⁻¹・ E ・ A ・ F ・ F ⁻¹ = A
Thus, the characteristics of the device can be obtained.

When the de-embedding method is used, the RRRR calibration procedure that requires positioning of the calibration reference with high accuracy is performed in a laboratory environment, the error factors of each jig are determined with high accuracy, and the error factors in the mass production process Can be mass-produced using a known jig. Of course, the error of the jig is removed by de-embedding the error factor obtained in the laboratory.
By doing so, the RRRR method can be operated without preparing a calibration reference positioning means or the like with high accuracy in each process, which is advantageous in terms of cost and process control.

When the measuring instrument is equipped with a computer and dedicated software, and the calibration reference residual inductance and transmission path parameters (phase constant β [rad / mm] and transmission loss δ [dB / Hz]) and the calibration reference contact position are entered, It is also possible to automatically calculate the calibration reference characteristic at the position based on Equations 1 to 3, and use this for the correction calculation of Equations 10 to 13. In short, the network analyzer can automatically predict the value of the calibration reference and perform RRRR calibration.
In the inspection process of devices in a mass production factory, it is not necessary for an operator or the like to calculate a calibration reference value, and since the RRRR calibration can be performed by a single measuring instrument, the process can be simplified.

If the calibration standard (for example, short-circuit standard) has a large effect on the residual inductance due to the high frequency, etc., and the calibration standard is connected to the transmission line, it is not close enough to the short-circuit (the signal passes between the ports) If total reflection cannot be obtained).
In this case, as shown in FIG. 15A, the calibration reference 25 is lifted from the transmission line 12, and the capacitance C [F] generated between the transmission line and the calibration reference and the calibration reference residual inductance L [H]. Is in a series resonance state. In this case, C = 1 / (2πf√L) is set.
Instead of using the stray capacitance between the calibration reference and the transmission line, the calibration reference 26 can be brought into contact with the transmission line 12 for series resonance as shown in FIG. In this case, the calibration standard 26 may be a very small capacitor.
In the series resonance state, the impedance of the calibration reference connection portion is 0Ω, that is, an ideal short-circuit state. That is, the same effect as using a good short-circuit reference can be obtained even at high frequencies where a good short-circuit reference cannot be obtained.

FIG. 16 shows an example of a measuring jig having three ports.
In the figure, 30 is a jig substrate, 31 to 33 are three signal conductors formed on the upper surface of the jig substrate 30, and 34 is also arranged to sandwich both sides of the signal conductors 31 to 33 on the upper surface of the jig substrate 30. The formed ground conductors 35 to 37 are connectors provided at the ends of the jig substrate 30. One ends of the signal conductors 31 to 33 are opposed to each other in three directions, and the other ends are connected to the connectors 35 to 37, respectively. A calibration standard is connected between each of the signal conductors 31 to 33 and the ground conductor 34, and after correction is performed, the subject is between the signal conductors 31 to 33, or between the signal conductors 31 to 33 and the ground conductor 32. 38 is connected and the electrical characteristics are measured.
In this way, the electrical characteristics of the subject 38 having three or more terminals can be measured.

In the above-described embodiment, an example in which a coplanar wave guide is used as a transmission line is shown. However, a slot line 40 as shown in FIG. 17 can also be used. In the slot line 40, signal conductors 41 and 42 and a ground conductor 43 are provided on the same plane with a gap therebetween. In this case, the electrical property is measured by connecting the subject 44 between the signal conductors 41 and 42 or between the signal conductors 41 and 42 and the ground conductor 43.

The high-frequency electrical characteristic measuring method according to the present invention is not limited to the above-described embodiment.
The measuring instrument in the present invention is not limited to a network analyzer, and any measuring instrument that can measure high-frequency electrical characteristics can be used.
Although the calibration reference is measured at the subject measurement position, it is not necessary to measure the calibration reference at the subject measurement position. In this case, all three or more calibration reference measurements are expressed in the form of Equation 1.
The transmission path is not limited to a planar transmission path, as long as calibration standards can be connected, through-chips can be connected in series, and an object can be connected between signal conductors or between signal conductors and a ground conductor. Any structure can be used.
Although an example using a measurement jig having 1 port to 3 ports has been described, a measurement jig having 4 ports or more can also be used. In this case, the same correction and measurement can be performed.

As described above, the high-frequency electrical characteristic measuring method according to the present invention has the following effects.
(1) Since the transmission path used for the correction and the transmission path used for the subject measurement are the same, the transmission path is hardly affected by variations in the transmission path. In addition, the connection between the transmission line and the measuring instrument is fixed in correction and actual measurement, and there is no need for reconnection. Therefore, an accident such as a correction failure due to poor contact of the transmission line does not occur.
(2) The characteristics of a single part of the subject can be measured with high accuracy and are not affected by errors such as jigs. In particular, the measurement accuracy of electronic components having an impedance higher than the characteristic impedance of the transmission line is high.
(3) The subject can be measured not only with two terminals but also with electronic components with three or more terminals, and any target part that can be measured is not selected. Therefore, the present invention is a very effective method for accurately measuring the scattering coefficient and impedance value of electronic components such as filters, couplers and baluns, or impedance elements such as chip inductors and chip capacitors.

Claims (22)

In a method of measuring high frequency electrical characteristics of an electronic component,
Providing a transmission line having a plurality of signal conductors spaced apart from each other and at least one ground conductor and having a known electrical characteristic per unit length;
Connecting each of the signal conductors and the ground conductor to a measurement port of a measuring instrument,
Measuring the electrical characteristics by connecting the signal conductor and the ground conductor in at least three locations in the length direction of each signal conductor; and
A step of measuring electrical characteristics between the signal conductors in a through state;
From the measured value in the connected state, the measured value in the through state and the electrical characteristics of the transmission line, obtaining an error factor of the measurement system including the transmission line;
Measuring electrical characteristics by connecting an electronic component to be measured between the signal conductors or between the signal conductors and the ground conductor;
Removing the error factor of the measurement system from the measured value of the electronic component to be measured, and obtaining the true value of the electric characteristic of the electronic component to be measured. In a method of measuring high frequency electrical characteristics of an electronic component,
Providing a transmission line having a plurality of signal conductors spaced apart from each other and at least one ground conductor, and having an unknown electrical characteristic per unit length;
Connecting each of the signal conductors and the ground conductor to a measurement port of a measuring instrument,
Measuring the electrical characteristics by connecting the signal conductor and the ground conductor in at least four locations in the length direction of each signal conductor; and
A step of measuring electrical characteristics between the signal conductors in a through state;
From the measurement value in the connection state and the measurement value in the through state, obtaining an error factor of the measurement system including the transmission path and electrical characteristics of the transmission path;
Measuring electrical characteristics by connecting an electronic component to be measured between the signal conductors or between the signal conductors and the ground conductor;
Removing the error factor of the measurement system from the measured value of the electronic component to be measured, and obtaining the true value of the electric characteristic of the electronic component to be measured. In a method of measuring high frequency electrical characteristics of an electronic component,
Providing a transmission line having a plurality of signal conductors spaced apart from each other and at least one ground conductor and having a known electrical characteristic per unit length;
Connecting each of the signal conductors and the ground conductor to a measurement port of a measuring instrument,
Measuring the electrical characteristics by connecting the signal conductor and the ground conductor in at least three locations in the length direction of each signal conductor; and
Measuring electrical characteristics by connecting an electronic component to be measured between the signal conductors or between the signal conductors and the ground conductor;
Obtaining an error factor of the measurement system including the transmission path from the measurement value in the connection state, the measurement value measured by connecting the electronic device to be measured, and the electrical characteristics of the transmission path;
Removing the error factor of the measurement system from the measured value of the electronic component to be measured, and obtaining the true value of the electric characteristic of the electronic component to be measured. In a method of measuring high frequency electrical characteristics of an electronic component,
Providing a transmission line having a plurality of signal conductors spaced apart from each other and at least one ground conductor, and having an unknown electrical characteristic per unit length;
Connecting each of the signal conductors and the ground conductor to a measurement port of a measuring instrument,
Measuring the electrical characteristics by connecting the signal conductor and the ground conductor in at least four locations in the length direction of each signal conductor; and
Measuring electrical characteristics by connecting an electronic component to be measured between the signal conductors or between the signal conductors and the ground conductor;
From the measurement value in the connection state and the measurement value measured by connecting the electronic device to be measured, obtaining an error factor of the measurement system including the transmission path and the electrical characteristics of the transmission path;
Removing the error factor of the measurement system from the measured value of the electronic component to be measured, and obtaining the true value of the electric characteristic of the electronic component to be measured. 5. The method of measuring high-frequency electrical characteristics according to claim 1, wherein a short-circuit reference is brought into contact with the signal conductor and the ground conductor in order to connect the signal conductor and the ground conductor. . 6. The step of measuring the electrical characteristics by connecting the signal conductor and the ground conductor is performed in a state where a through chip is connected between the signal conductors. High frequency electrical property measurement method. With the through chip connected between the signal conductors, the transmission coefficient is measured by connecting the signal conductor and the ground conductor, and a sub-step of detecting a contact failure in the connection state based on the measured transmission coefficient The high frequency electrical property measuring method according to claim 6, comprising: In order to connect the signal conductor and the ground conductor, a calibration reference is brought into contact with or close to the signal conductor and the ground conductor, and a capacitance within the calibration reference or a capacitance between the calibration reference and the transmission line 5. The high-frequency electrical characteristic measuring method according to claim 1, wherein series resonance is performed with the residual inductance of the calibration standard. 2. The high frequency electrical characteristic measuring method according to claim 1, wherein a through chip having no directivity in a transmission coefficient is connected in series between the signal conductors in order to achieve the through state. 5. The measurement value obtained by measuring the transmission line in an open state, in addition to the measurement value in the connection state and the through state, is used to obtain an error factor of the measurement system. A method for measuring high-frequency electrical characteristics according to claim 1. 10. The method for measuring high-frequency electrical characteristics according to claim 1, wherein the step of obtaining an error factor of a measurement system including the transmission path is executed according to the following equation.

Γ _A1 : reflection coefficient at the first measurement position, Γ _A2 : reflection coefficient at the second measurement position, Γ _A3 : reflection coefficient at the third measurement position, S _11M1 : measurement at the first measurement position Value, S _11M2 : measured value at the second measuring position, S _11M3 : measured value at the third measuring position, S _11MT : reflection coefficient in the through state, S _21MT : transmission coefficient in the through state, E _xx, F _xx : Error factor of measurement system. The step of removing an error factor of the measurement system from the measurement value of the electronic component to be measured and obtaining the true value of the electrical characteristic of the electronic component to be measured is executed according to the following equation. Of measuring high-frequency electrical characteristics of electronic parts.

In the above equation, S _{11A is} the reflection coefficient of the electronic component to be measured, and S _{21A is} the transmission coefficient of the electronic component to be measured. 13. The high-frequency electrical characteristic measuring method according to claim 1, wherein the transmission line is a transmission line in which a signal conductor and a ground conductor are formed on the same plane. The high-frequency electrical characteristic measuring method according to claim 13, wherein the transmission line is a coplanar wave guide having a signal conductor and a ground conductor on both sides of the signal conductor. The high-frequency electrical characteristic measuring method according to claim 13, wherein the transmission line is a slot line in which a signal conductor and a ground conductor are provided at an interval. The position at which the signal conductor and the ground conductor are connected to measure the electrical characteristics is a position where the phase difference between the positions is 70 ° to 145 °. 2. A method for measuring high-frequency electrical characteristics according to 1. In a device that measures high-frequency electrical characteristics of electronic components,
A transmission line having a plurality of signal conductors spaced apart from each other and at least one ground conductor, and having a known electrical characteristic per unit length;
A measuring port connected to each of the signal conductors, a measuring port connected to the ground conductor, and a measuring instrument capable of measuring high-frequency electrical characteristics;
Means for connecting the signal conductor and the ground conductor in at least three locations in the length direction of each signal conductor;
Means for bringing the signal conductors into a mutually through state;
Means for determining an error factor of a measurement system including the transmission line from the measurement value in the connection state, the measurement value in the through state, and the electrical characteristics of the transmission line;
Means for connecting an electronic component to be measured between the signal conductors or between the signal conductors and the ground conductor;
An error factor of the measurement system is removed from a measurement value measured by connecting the measured electronic component between the signal conductors or between the signal conductor and the ground conductor, and the electrical characteristics of the measured electronic component A high-frequency electrical characteristic measuring apparatus for electronic parts, comprising: In a device that measures high-frequency electrical characteristics of electronic components,
A transmission line having a plurality of signal conductors arranged at a distance from each other and at least one ground conductor, and having an unknown electrical characteristic per unit length;
A measuring port connected to each of the signal conductors, a measuring port connected to the ground conductor, and a measuring instrument capable of measuring high-frequency electrical characteristics;
Means for connecting the signal conductor and the ground conductor in at least four locations in the length direction of each signal conductor;
Means for bringing the signal conductors into a mutually through state;
From the measurement value in the connection state and the measurement value in the through state, obtaining an error factor of the measurement system including the transmission path and electrical characteristics of the transmission path;
Means for connecting an electronic component to be measured between the signal conductors or between the signal conductors and the ground conductor;
An error factor of the measurement system is removed from a measurement value measured by connecting the measured electronic component between the signal conductors or between the signal conductor and the ground conductor, and the electrical characteristics of the measured electronic component A high-frequency electrical characteristic measuring apparatus for electronic parts, comprising: The high-frequency signal according to claim 16 or 17, wherein the means for connecting the signal conductor and the ground conductor includes a short-circuit reference and a means for bringing the short-circuit reference into contact with the transmission line. Electrical property measuring device. 20. The means for setting the through state includes a through chip having no directivity in transmission coefficient, and means for connecting the through chip in series with a transmission line. High-frequency electrical property measuring device. In the calibration method of the high-frequency electrical property measuring device for electronic components,
Providing a transmission line having a plurality of signal conductors spaced apart from each other and at least one ground conductor and having a known electrical characteristic per unit length;
Connecting each of the signal conductors and the ground conductor to a measurement port of a measuring instrument,
Measuring the electrical characteristics by connecting the signal conductor and the ground conductor in at least three locations in the length direction of each signal conductor; and
A step of measuring electrical characteristics between the signal conductors in a through state;
And a step of obtaining an error factor of a measurement system including the transmission line from a measurement value in the connection state, a measurement value in a through state, and electrical characteristics of the transmission line. In the calibration method of the high-frequency electrical property measuring device for electronic components,
Providing a transmission line having a plurality of signal conductors spaced apart from each other and at least one ground conductor, and having an unknown electrical characteristic per unit length;
Connecting each signal conductor and the ground conductor to a measurement port of a measuring instrument,
Measuring the electrical characteristics by connecting the signal conductor and the ground conductor in at least four locations in the length direction of each signal conductor; and
A step of measuring electrical characteristics between the signal conductors in a through state;
And a step of obtaining an error factor of a measurement system including the transmission line and an electrical characteristic of the transmission line from a measurement value in the connection state and a measurement value in the through state.

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