JP3526517B2 - High frequency measurement board - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency measurement used for measuring electrical characteristics of a semiconductor device using a microstrip line, a semiconductor device housing package, or a circuit board at a high frequency band such as a microwave band or a millimeter wave band. More specifically, the present invention relates to a wide-band, low-loss high-frequency measurement substrate with an improved measurable frequency band.

[0002]

2. Description of the Related Art In measuring and evaluating the electrical characteristics of a semiconductor element or a package / circuit board for storing a semiconductor element in a high frequency band such as a microwave band or a millimeter wave band,
On the measuring instrument side, a wafer probe is used which enables high-accuracy measurement by contact with the coplanar line. On the other hand, the transmission line of the input / output part on the DUT side such as a high-speed digital circuit for a wireless communication device using a high-frequency signal or a high-frequency circuit or a high-frequency semiconductor element or a high-frequency semiconductor element housing package that accommodates it is a micro Strip lines are common. For this reason, it is necessary to provide a line conversion unit for connecting the coplanar line of the wafer probe and the microstrip line of the DUT in order to measure the electrical characteristics at a high frequency using the wafer probe. Requires high-frequency signal transmission with low loss in order to extract the characteristics of the device under test with high accuracy.

Conventionally, as the structure of the line converting portion, generally, the signal conductor width and the ground conductor width of the coplanar line portion are appropriately designed so as to correspond to the size required by the head of the wafer probe, and one end thereof and a micro One end of the strip line is connected so that the mutual signal conductor width changes smoothly, and the ground (ground) conductor of the coplanar line is connected to the ground conductor on the back surface of the microstrip line and a through conductor such as a through hole or via hole. It was configured to connect.

For example, as shown in a plan view of an example of a structure of a conventional line conversion portion in FIG. 12, a dielectric substrate 1 having a relative permittivity of 9.6.
A conductor film is formed on almost the entire back surface of the substrate to form a ground conductor, and the width of the signal conductor 2 in the microstrip line section is set to 190.
μm, the width of the signal conductor 3 in the coplanar line portion is 160 μm,
Signal conductor 3 and ground conductors 4 and 4'of the coplanar line section
And the ground conductors 4 and 4'of the coplanar line section are electrically connected to the ground conductor on the rear surface through through holes 5 and 5'each having a diameter of 150 μm and are through conductors. Is used. Then, when the ground conductors of the coplanar line portion having the through-hole pad structure are made to have the same shape and are mirror-symmetrically opposed to each other through the microstrip line portion, the electrical characteristics are extracted by measurement, and the diagram is shown in FIG. The frequency characteristic as shown by is obtained.

In FIG. 13, the horizontal axis represents frequency (unit: GH
z), the vertical axis represents the transmission coefficient (unit: dB) as an evaluation index of the transmitted amount of the input signal, and the characteristic curve represents the frequency characteristic of the transmission coefficient. From this result, the transmission coefficient decreases as the frequency increases,
It can be seen that the amount of signal transmission decreases.

[0006] Further, as described above, a utility model registration No. 2507797 "Microstrip" is used in which a coplanar line and a microstrip line are line-converted without using a through conductor such as a through hole or a via hole to constitute a high frequency measurement substrate. There is a line circuit measurement jig. According to the publication, as shown in a plan view in FIG. 14, the measuring jig (measuring substrate) 10 has a step-like end of a microstrip line 12 on a dielectric substrate 11 having a ground conductor on the back surface. Alternatively, the probe head 13 may be formed in a tapered shape and its width
Corresponding to the center conductor width of the probe head. Also, an equivalent ground is formed by a radial stub 14 in the shape of a semi-circle or a semi-circle near the tip to correspond to the conductors of the two ground lines of the probe head 13. Let and radial stub
The configuration was such that the stub radius of 14 was an effective length of about 1/2 wavelength of the lower limit of the measurement frequency.

Further, according to such a configuration, since the bonding means between the ground conductors such as ribbon bonding and the variable element such as the above-mentioned through conductor does not intervene in the coupling between the probe head 13 and the measurement jig 10, the measurement data That is, good reproducibility of is obtained.

This semicircular or fan-shaped radial stub 14
It can be said that the principle of the equivalent ground by is equivalent to the general phenomenon of radial stub in a high frequency circuit.

That is, this content is IEEE TRANSACTIONS
ON MICROWAVE THEORY AND TECHNIQUES, VOL.36, NO.7,
JULY 1988 "A Coplanar Probe to Microstrip Transit
Based on “ion”, the reactance value X of the radial stub 15 having the shape shown in the plan view of FIG. 15 is calculated by calculating the thickness h of the substrate on which the radial stub 15 is formed, the inner diameter r _{1 of the} radial stub 15, and the outer diameter. Radius r ₂ · Radial central angle θ · Effective relative permittivity ε _re when propagating radial in the radial direction · Free space wavelength λ ₀

[0010]

[Equation 1]

[0011]

[Equation 2]

[0012]

[Equation 3]

[0013]

[Equation 4]

[0014]

[Equation 5]

Where J _i (x) and N _i (x) are i
Here is the Bessel function

On the basis of such a principle, the radial stub has an effect that it can be regarded as an equivalent ground because the operation at high frequency is close to a perfect reflection state, so that it can be applied as an equivalent ground on a high frequency measuring substrate. The radial stub 14 of utility model registration No. 2507797 uses such an effect.

Next, the characteristics of the high-frequency measuring substrate formed by such radial stubs are extracted.

FIG. 9 is a plan view showing an example of a conventional substrate for high frequency measurement using a radial stub. A metal film as a ground conductor is deposited on almost the entire back surface of a dielectric substrate 21 having a relative permittivity of 9.6. The signal conductor 22 of the microstrip line and the signal conductors 23 and 23 'of the coplanar line are formed on the surface, and the ground conductors 24 and 24' of the coplanar line are formed.
Installed at a distance of 135 μm from 23 ・ 23 'and ground conductor
24 and 24 'each have an inner diameter of 215 μm and an outer diameter of 580 μm
It is formed as a fan-shaped radial stub with a central angle of 230 °. When the electrical characteristics of this high frequency substrate were extracted by measurement, the results shown in the diagrams of FIGS. 10 and 11 were obtained.

In FIG. 10, the horizontal axis represents frequency (unit: GH
z), the vertical axis represents the reflection coefficient (unit: dB) as an evaluation index of the reflected amount in the input signal, the solid line in the characteristic curve represents the simulation result, and the broken line represents the measured value. Shown respectively.

Further, in FIG. 11, the horizontal axis represents the frequency (unit: GHz), and the vertical axis represents the transmission coefficient (unit: dB) as an evaluation index of the transmitted amount of the input signal. The solid line in the curve shows the simulation result,
The broken lines indicate the measured values. From these results, it can be seen that by using the radial stub as an equivalent ground, a high frequency measurement substrate having a low loss transmission frequency band characteristic can be obtained.

[0021]

However, in the conventional substrate for high frequency measurement as described above, when a through conductor such as a through hole or a via hole as shown in FIG. Furthermore, as a result of the ground component becoming unstable due to the inductance component of the through conductor in the high frequency band of the millimeter wave band, discontinuity of the characteristic impedance occurs, reflection increases with respect to the incident signal, and the amount of transmission of the high frequency signal increases. There was a problem of decrease. In addition, there is a problem that it is difficult to manufacture the high frequency measurement substrate with high accuracy because the through conductor processing step is required.

Further, as shown in FIG. 14 and FIG. 9, when an equivalent gland with a semi-circular or fan-shaped radial stub is used, the semi-circular or fan-shaped radial gland has a circumferential center of a substantially central position. At a frequency whose length corresponds to the effective length of one wavelength, the charge distribution in the circumferential direction becomes a standing distribution in which the density becomes higher at the end portions and the intermediate portion in the semicircular or fan-shaped circumferential direction, resulting in resonance. There was a problem that was caused. For this reason, the effect of the equivalent ground hardly occurs in the vicinity of this resonance frequency, and as a result, the characteristic impedance becomes discontinuous, so that the reflection with respect to the incident signal increases and the transmission amount of the high frequency signal decreases. There was a problem. Further, when the resonance frequency is a frequency in or near the low-frequency transmission frequency band, there is a problem that the measurable frequency band is narrowed.

The present invention has been made in view of the above problems in the prior art, and an object of the present invention is to provide a high-frequency measurement substrate using a radial stub as an equivalent ground so that the resonance frequency of the radial stub is on the low frequency side. The purpose of the present invention is to provide a substrate for high frequency measurement in which the low-loss transmission frequency band is widened by moving to low temperature.

[0024]

According to a first aspect of the present invention, there is provided a high frequency measuring substrate in which a ground conductor is formed on substantially the entire lower surface of a dielectric substrate, and a signal conductor of a microstrip line and the signal conductor are provided on the upper surface. A substantially radial stub-shaped equivalent ground conductor provided in the vicinity of the tip of each of the signal conductors and the ground conductor are electrically connected to the signal conductor and the equivalent ground conductor, respectively. A high-frequency measurement substrate to be connected, wherein the equivalent grounding conductor is a plurality of radial-shaped conductors having different radial lengths and arranged in a substantially arcuate shape sharing a center and having a plurality of radial-shaped conductors. It is characterized by comprising a connecting conductor for electrically connecting between the two.

A high frequency measuring substrate according to claim 2 of the present invention is the high frequency measuring substrate according to claim 1, wherein
It is characterized in that the radial length of the connection conductor is not more than half of the radial length of the radial conductor having the shortest radial length.

A high frequency measuring board according to a third aspect of the present invention is the high frequency measuring board according to the first or second aspect, wherein the plurality of radial conductors are located in a central radial conductor. And outer radial-shaped conductors which are arranged on both sides of the central radial-shaped conductor and whose central angle is approximately one half of the central angle of the central radial-shaped conductor.

[0027]

According to the first aspect of the present invention, there is provided a ground conductor formed on substantially the entire lower surface of a dielectric substrate, and a signal conductor of a microstrip line and the signal conductor on the upper surface. A substantially radial stub-shaped equivalent ground conductor provided in the vicinity of the tip of each of the signal conductors and the ground conductor are electrically connected to the signal conductor and the equivalent ground conductor, respectively. A high-frequency measurement substrate to be connected, wherein the equivalent grounding conductor is a plurality of radial-shaped conductors having different radial lengths and arranged in a substantially arcuate shape sharing a center and having a plurality of radial-shaped conductors. By including the connecting conductors that electrically connect between them, the semi-circular, fan-shaped, or fan-shaped, circumferential, standing charge density distribution in a substantially radial stub-shaped equivalent ground conductor becomes uniform. And thus in comparison with the case of a configuration using a radial shaped conductor occur at frequencies of a lower frequency side. Therefore, in a radial stub-shaped equivalent grounding conductor as in the conventional case, a semicircular or fan-shaped radial center has a circumferential length at a substantially central position corresponding to an effective length of one wavelength. When the frequency becomes, the charge distribution in the circumferential direction becomes a standing distribution in which the density becomes high at the end portions and the intermediate portion in the semicircular or fan-shaped circumferential direction, and compared with the case where resonance occurs, The resonance frequency can be moved to the low frequency side of the low loss transmission frequency band. as a result,
Since the low-loss transmission frequency band is widened, the high-frequency measurement substrate has a wide-band, low-loss characteristic.

According to a second aspect of the present invention, there is provided the high frequency measurement substrate according to the first aspect, wherein the radial length of the connecting conductor is the shortest radial length. By setting the radial-shaped conductor to have half or less of its radial length, the semi-circular, fan-shaped or fan-shaped circumferential charge density distribution in a substantially radial stub-shaped equivalent ground conductor becomes uniform. It occurs at a frequency on the lower frequency side as compared with the case where the radial conductor is used. Therefore, in a radial stub-shaped equivalent grounding conductor as in the conventional case, a semicircular or fan-shaped radial center has a circumferential length at a substantially central position corresponding to an effective length of one wavelength. When the frequency becomes, the charge distribution in the circumferential direction becomes a standing distribution in which the density becomes high at the end portions and the intermediate portion in the semicircular or fan-shaped circumferential direction, and compared with the case where resonance occurs, The resonance frequency can be moved to the low frequency side of the low loss transmission frequency band.

As a result, a low-loss transmission frequency band is widened, so that a high-frequency measurement substrate having a low-loss characteristic in a wide band is obtained.

According to a third aspect of the present invention, there is provided a high frequency measuring substrate according to the first or second aspect, wherein a plurality of radial conductors are located in a central radial shape. Since the conductor and the outer radial conductor arranged on both sides of the central radial conductor and having a central angle of about ½ of the central angle of the central radial conductor, a substantially radial stub shape The semi-circular, fan-shaped or fan-shaped circumferential charge density distribution in the equivalent ground conductor of is generated at a frequency on the lower frequency side compared to the case where it is composed of a single radial-shaped conductor. Become. Therefore, in a radial stub-shaped equivalent grounding conductor as in the conventional case, a semicircular or fan-shaped radial center has a circumferential length at a substantially central position corresponding to an effective length of one wavelength. When the frequency becomes, the charge distribution in the circumferential direction becomes a standing distribution in which the density becomes high at the end portions and the intermediate portion in the semicircular or fan-shaped circumferential direction, and compared with the case where resonance occurs, The resonance frequency can be moved to the low frequency side of the low loss transmission frequency band. As a result, the low-loss transmission frequency band is widened, so that the high-frequency measurement substrate has a wide-band, low-loss characteristic.

In each of the above-mentioned high-frequency measurement substrates of the present invention, the plurality of radial-shaped conductors each have a central angle of at least two types, or the connecting conductors form a plurality of radial-shaped conductors. By connecting the inner peripheral portion or connecting the outer peripheral portions of the plurality of radial-shaped conductors by the connecting conductor, the above-described operational effects of the high-frequency measuring substrate of the present invention can be more effectively exhibited.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a plan view showing an example of an embodiment of a high frequency measuring substrate of the present invention. In FIG. 1, 31 is a dielectric substrate in which a ground conductor is formed on substantially the entire back surface (lower surface), and 32 is a signal conductor of a microstrip line formed on the front surface (upper surface) of the dielectric substrate 31. . Reference numeral 33 denotes a signal conductor of the coplanar line portion, which is electrically connected to the signal conductor 32 of the microstrip line and forms the tip of the signal conductor 32, and is a signal conductor of a wafer probe (not shown) having a coplanar line structure. The signal conductor of the microstrip line
It corresponds to the part that contacts 32 and is electrically connected.

34, 34 ', 34 "are radial conductors, each of which has a substantially semicircular shape and is arranged in a generally arcuate shape with the center shared in the vicinity of the tip of the signal conductor 32 of the microstrip line.
It is formed of a fan-shaped or fan-shaped conductor pattern. In this example, of the radial conductors 34, 34 ', 34 ", the radial length of the central radial conductor 34' located at the center is the outer radial conductor 34.
Longer than 34 ", and also has a radially outer conductor 34.
The central angle of 34 "is approximately 1/2 of the central angle of the central radial conductor 34 '.

Reference numerals 35, 35 'are connection conductors for electrically connecting the plurality of radial-shaped conductors 34, 34', 34 ", respectively, and conductors similar to the radial-shaped conductors 34, 34 ', 34", respectively. Radial-shaped conductor 34.34 '
It is formed to be shorter than the radial length of 34 ", and in this example, the radial length of the connecting conductors 35/35 'is 2 minutes of the radial length of the radial conductor 34/34". Of 1
In the following, the inner peripheral portions of the radial conductors 34, 34 ', 34 "are connected.

These plural radial-shaped conductors 34, 34 ',
34 ″ and the connecting conductors 35 and 35 ′ form an equivalent ground conductor 36 having a substantially radial stub shape, and the shape, size, position, etc. of the equivalent ground conductor 36 are set in the same manner as a conventional radial stub. It is appropriately set by extending both ends in accordance with the tip shape of the signal conductor 32 of the microstrip line so as to satisfy desired high-frequency characteristics.

The dimensions, shapes, positions, etc. of the radial conductors 34, 34 ', 34 "and the connecting conductors 35, 35' do not adversely affect the high frequency and are at frequencies lower than the transmission frequency band. It may be appropriately set so that a stationary charge density distribution is generated. For example, since the high-frequency coupling with the ground conductor on the back surface is made as strong (as many) as possible to obtain a wide band, each radial-shaped conductor 34. In order to make the central angle (radial angle) of 34 '・ 34 "large, the circumferential length of the connecting conductors 35 ・ 35' should be shorter than the radial length.

As described above, the plurality of radial-shaped conductors 34.
34 '・ 34 "are provided, and each radial shape conductor 34 ・ 34' ・
By electrically connecting 34 "between the connecting conductors 35 and 35 'to form the equivalent ground conductor 36, the radial end in the circumferential direction can be compared with the case where only a single equivalent ground conductor is formed. Since the path of the current flowing from to the end becomes long, the frequency corresponding to one wavelength of the path becomes low, and the frequency at which the charge density distribution on the radial stub becomes a stationary distribution moves to the low frequency side. However, since the charge density distribution is a standing distribution, it is most effective to set the center angle of each equivalent ground conductor so that it is separated at a location where the current density is high in a single equivalent ground conductor. is there.

FIG. 2 is a plan view showing another example of the embodiment of the high frequency measuring substrate of the present invention. In FIG. 2, reference numeral 41 is a dielectric substrate in which a ground conductor is formed on substantially the entire back surface (lower surface), and 42 is the front surface (upper surface) of the dielectric substrate 41.
It is a signal conductor of a microstrip line formed in. Reference numeral 43 denotes a signal conductor of the coplanar line portion, which is electrically connected to the signal conductor 42 of the microstrip line and forms the tip of the signal conductor 42, and is a signal conductor of a wafer probe (not shown) having a coplanar line structure. Corresponds to a portion for contacting and electrically connecting to the signal conductor 42 of the microstrip line.

Reference numerals 44, 44 ', and 44 "are radial conductors, each of which is a semicircular shape having a substantially arcuate shape with the center shared in the vicinity of the tip of the signal conductor 32 of the microstrip line.
It is formed of a fan-shaped or fan-shaped conductor pattern. In this example, of the radial conductors 44, 44 ', 44 ", the outer radial conductors 44, 44', 44 ', which are the radial lengths of the central radial conductor 44' located at the center, are arranged on both sides thereof.
Shorter than 44 ", and further radial outer shape conductor 44 ・
The central angle of 44 "is approximately 1/2 of the central angle of the central radial conductor 44 '.

Further, 45 and 45 'are connection conductors for electrically connecting the plurality of radial-shaped conductors 44, 44', and 44 ", and conductors similar to the radial-shaped conductors 44, 44 ', and 44", respectively. Radial-shaped conductor 44 ・ 44 '
Formed to be shorter than the radial length of 44 ", and in this example, the radial length of the connecting conductors 45 and 45 'is one half of the radial length of the radial conductor 44'. In the following, the inner peripheral portions of the radial conductors 44, 44 ', 44 "are connected.

Then, the plurality of radial-shaped conductors 44
-44'-44 "and the connecting conductors 45-45 'form an equivalent ground conductor 46 having a substantially radial stub shape.

FIG. 3 is a plan view showing still another example of the embodiment of the high frequency measuring substrate of the present invention. In FIG. 3, reference numeral 51 is a dielectric substrate in which a ground conductor is formed on substantially the entire lower surface, 52 is a signal conductor of a microstrip line formed on the upper surface of the dielectric substrate 51, and 53 is a signal of a coplanar line portion. A conductor, which is electrically connected to the signal conductor 52 of the microstrip line and serves as the tip of the signal conductor 52. The signal conductor of the wafer probe (not shown) having the coplanar line structure is connected to the signal conductor of the microstrip line. 52
Corresponds to a portion that is brought into contact with and electrically connected.

Reference numerals 54, 54 ', 54 "are radial conductors, each of which has a substantially semicircular shape and is arranged in a generally arcuate shape with a common center in the vicinity of the tip of the signal conductor 32 of the microstrip line.
It is formed of a fan-shaped or fan-shaped conductor pattern. In this example, the radial length of the central radial conductor 54 'located in the center of the radial conductors 54, 54', 54 "is the outer radial conductor 54
Shorter than 54 ", and also has a radially outer conductor 54.
The central angle of 54 "is approximately 1/2 of the central angle of the central radial conductor 54 '.

Further, 55.55 'are connection conductors for electrically connecting the plurality of radial-shaped conductors 54, 54', 54 ", and conductors similar to the radial-shaped conductors 54, 54 ', 54", respectively. Radial-shaped conductor 54 ・ 54 '
Formed to be shorter than the radial length of 54 ", and in this example, the radial length of the connecting conductors 55, 55 'is one half of the radial length of the radial conductor 54'. In the following, the outer peripheral portions of the radial conductors 54, 54 ', 54 "are connected.

Then, the plurality of radial-shaped conductors 54
54 'and 54' and the connecting conductors 55 and 55 'form an equivalent ground conductor 56 having a substantially radial stub shape.

[0046]

EXAMPLES Next, specific examples of the high frequency measurement substrate of the present invention will be described. Example 1 First, as a comparative example, in order to obtain a high-frequency measurement substrate according to the related art, a conventional high-frequency measurement substrate shown in a plan view in FIG. 7 was manufactured. In FIG. 7, reference numeral 61 is a dielectric substrate having a ground conductor deposited on substantially the entire lower surface thereof, 62 is a signal conductor of a microstrip line formed on the upper surface of the dielectric substrate 61, and 63 is a signal of a coplanar line portion. Reference numeral 64 is a conductor, and 64 is an equivalent ground conductor provided in the vicinity of the tip of the signal conductor 62 of the microstrip line and formed by a semi-circular or fan-shaped radial stub-shaped conductor pattern.

As shown in FIG. 7, the relative permittivity is 9.6 and the thickness is 20.
A metal film made of Cr / Cu / Ni / Au was adhered and formed on almost the entire back surface of a dielectric substrate 61 made of 0 μm alumina ceramics. In addition, a signal conductor 62 of a microstrip line is formed on the upper surface of the dielectric substrate 61 with a conductor width of 190 μm.
And the coplanar line portion 63 at the tip of the conductor width.
The distance between the signal conductor and the ground metal was set to 135 μm and electrically connected to the tip of the signal conductor 62 of the microstrip line. Furthermore, the signal conductor 63 of the coplanar line portion (the tip of the signal conductor 62 of the microstrip line)
With the inner diameter 21
By forming a fan-shaped radial stub with an outer diameter of 580 μm and a central angle of 230 ° as the equivalent ground conductor 64,
A sample A of a conventional substrate for high frequency measurement was prepared.

Next, as in the case of the sample A above, the others are the same as in FIG. 1, as shown in FIG.
The central angle of 34 '· 34 ”is that of the central radial shape conductor 34' is 110 °, that of the outer radial shape conductor 34 · 34” is 55 °.
And the radial length of the central radial conductor 34 '.
It is 415 μm (inner diameter 215 μm, outer diameter 630 μm), and that of outer radial shape conductor 34/34 ″ is 365 μm (inner diameter 21
5 μm and outer diameter 580 μm). Also, the radial length is 20 μm and the circumference is 20 μm so as to connect the inner peripheral portions of the radial-shaped conductors 34, 34 ′, 34 ″ so that a 5 ° gap is formed between these radial-shaped conductors. Direction length is about 20 μm
The connection conductors 35 and 35 'were electrically connected to prepare a sample B of the high frequency measurement substrate of the present invention.

Then, with respect to these sample A and sample B, the characteristics corresponding to the frequency from the end of the microstrip line that is not connected to the coplanar line to the end of the coplanar line that is not connected to the microstrip line are extracted by electromagnetic field simulation. Then, from the extracted characteristics, a transmission coefficient (S ₂₁ ) was obtained as a transmission characteristic with respect to frequency as an evaluation index of the transmitted amount of the input signal.

Of these results, S ₂₁ of sample A is shown diagrammatically in FIG. In FIG. 8, the horizontal axis represents frequency (unit:
GHz), the vertical axis represents the amount of transmission (unit: dB), and the characteristic curve represents the frequency characteristic of the transmission coefficient S ₂₁ .

Further, as a comparison of the transmission characteristics of the sample A and the sample B, the frequency characteristics of the transmission coefficient S ₂₁ of both are shown in a diagram in FIG. Also in FIG. 4, the horizontal axis represents frequency (unit: GHz),
The vertical axis represents the transmission amount (unit: dB), and S of sample B
_{21 is shown} by a solid line characteristic curve, and S ₂₁ of the sample A is shown by a broken line characteristic curve.

As can be seen from the above, the sample B, which is the high-frequency measuring substrate of the present invention, is a conventional high-frequency measuring substrate because the equivalent ground conductor is formed by connecting a plurality of radial-shaped conductors with connecting conductors. As compared with the case where a single radial-shaped equivalent ground conductor is used as in sample A, the resonance frequency moves to the low frequency side, so the low frequency side of the low loss frequency band expands. It has good broadband low loss transmission characteristics.

Thus, according to the high-frequency measuring board of the present invention, the equivalent ground conductor is electrically connected to the plurality of radial-shaped conductors by the connecting conductors, whereby the resonance frequency shifts to the low frequency side. Therefore, it was confirmed that the substrate for high frequency measurement has a good wide band low loss transmission characteristic.

Example 2 In the same manner as the sample A of [Example 1],
As shown in FIG. 2, a plurality of fan-shaped radial conductors 44
・ The central angle of 44 '・ 44 "is 110 ° of that of the central radial conductor 44', and that of the outer radial conductor 44 ・ 44" is 110 °.
55 ° and the radial length is the center radial shape conductor 4
4'of 365 μm (inner diameter 215 μm, outer diameter 580 μm
m), that of the outer radial conductor 44.44 "is 415 μm
(Inner diameter 215 μm, outer diameter 630 μm). In addition, the radial length is 20 μm and the circumference is 20 μm so as to connect the inner peripheral portions of the radial conductors 44, 44 ′, and 44 ″ so that a 5 ° gap is formed between these radial conductors. Electrical connection was made with the connecting conductors 45 and 45 ′ having a length in the direction of approximately 20 μm to prepare a sample C of the high frequency measurement substrate of the present invention.

Then, the characteristics of these sample A and sample C were extracted in the same manner as in [Example 1], and from the extracted characteristics,
A transmission coefficient (S ₂₁ ) was obtained as a transmission characteristic with respect to frequency as an evaluation index of the transmitted amount of the input signal.

Regarding these results, FIG. 5 shows a comparison of the characteristics of Sample A and Sample C in a diagram. Also in FIG. 5, the horizontal axis represents frequency (unit: GHz) and the vertical axis represents transmission amount (unit: dB).
S ₂₁ of Sample C is shown by a solid line characteristic curve, and S ₂₁ of Sample A is shown by a broken line characteristic curve.

As can be seen from the above, the sample C, which is the high-frequency measurement substrate of the present invention, is formed by electrically connecting an equivalent grounding conductor with a plurality of radial-shaped conductors by connecting conductors, and thus the conventional high-frequency measurement is performed. Sample A which is the substrate
The resonance frequency moves to the low frequency side as compared with the case where a single radial-shaped equivalent grounding conductor is used, as shown in Fig. 4, so that the low frequency side of the low loss frequency band is widened and a good wide band is obtained. It has low loss transmission characteristics.

In comparison with Sample B, Sample C resonates on the high frequency side due to the difference in the length of the path in which the charge density distribution occurs, and the resonance frequency varies depending on the shapes and dimensions of the plurality of radial conductors. It was also confirmed that the movement amount can be set to a desired value.

Thus, according to the high-frequency measuring board of the present invention, the equivalent ground conductor is electrically connected to the plurality of radial-shaped conductors by the connecting conductors, whereby the resonance frequency shifts to the lower frequency side. Therefore, it was confirmed that the substrate for high frequency measurement has a good wide band low loss transmission characteristic.

Example 3 In the same manner as the sample A of [Example 1],
As shown in FIG. 3, a plurality of fan-shaped radial conductors 54
・ The central angle of 54 '・ 54 "is 110 ° of that of the central radial shape conductor 54', and that of the outer radial shape conductor 54 ・ 54" is
55 ° and the radial length is 5
4'of 365 μm (inner diameter 265 μm, outer diameter 630 μm
m), that of the outer radial shaped conductor 54.54 "is 415 μm
(Inner diameter 215 μm, outer diameter 630 μm). In addition, the radial length is 20 μm so that the outer circumferences of the radial conductors 54, 54 ′, 54 ″ are connected so that a 5 ° gap is formed between these radial conductors. Was electrically connected by the connecting conductors 55 and 55 ′ having a length of about 20 μm to prepare a sample D of the high frequency measurement substrate of the present invention.

Then, the characteristics of these sample A and sample D were extracted in the same manner as in [Example 1], and from the extracted characteristics,
A transmission coefficient (S ₂₁ ) was obtained as a transmission characteristic with respect to frequency as an evaluation index of the transmitted amount of the input signal.

Regarding these results, FIG. 6 shows a comparison of the characteristics of the sample A and the sample D by a diagram. Also in FIG. 6, the horizontal axis represents frequency (unit: GHz), and the vertical axis represents transmission amount (unit: dB).
S ₂₁ of Sample D is shown by a solid characteristic curve, and S ₂₁ of Sample A is shown by a broken characteristic curve.

As can be seen from the above, the sample D, which is the high frequency measurement substrate of the present invention, is formed by electrically connecting an equivalent grounding conductor with a plurality of radial-shaped conductors by connecting conductors, and thus the conventional high frequency measurement is performed. Sample A which is the substrate
The resonance frequency moves to the low frequency side as compared with the case where a single radial-shaped equivalent grounding conductor is used, as shown in Fig. 4, so that the low frequency side of the low loss frequency band is widened and a good wide band is obtained. It has low loss transmission characteristics.

In particular, according to the shape of the sample D, since the path in which the charge density distribution is generated is the longest, the charge distribution is greatly changed. Therefore, the resonance frequency is extremely effectively moved to the low frequency side. I was able to.

Thus, according to the high frequency measurement board of the present invention, the equivalent ground conductor is electrically connected to the plurality of radial-shaped conductors by the connection conductors, so that the resonance frequency shifts to the low frequency side. Therefore, it was confirmed that the substrate for high frequency measurement has a good wide band low loss transmission characteristic.

The above is merely an example of the embodiments of the present invention, and the present invention is not limited to these, and various changes and improvements may be made without departing from the gist of the present invention. No problem.

[0067]

As described above, according to the high frequency measurement board of the first aspect of the present invention, the equivalent ground conductor is arranged in a substantially arcuate shape with the center shared, and has a radial length. Since it is composed of a plurality of radial-shaped conductors with different values and a connection conductor that electrically connects the plurality of radial-shaped conductors, the semi-circular / fan-shaped or fan-shaped Since the static charge density distribution in the circumferential direction of the is generated at a frequency on the lower frequency side compared to the case where it is composed of a single radial-shaped conductor, the equivalent radial stub shape When the frequency in which the length in the circumferential direction of the semicircular or fan-shaped substantially central position in the radial direction of the ground conductor corresponds to the effective length of one wavelength is a frequency within the low-loss transmission frequency band, the charge distribution in the circumferential direction is Half circle or fan The resonance frequency is moved to the low frequency side of the low-loss transmission frequency band, as compared with the case where resonance occurs due to a standing distribution in which the density becomes high at the circumferential end and the middle part. As a result, the low-loss transmission frequency band is widened, so that a high-frequency measurement substrate having low-bandwidth characteristics can be obtained.

According to a second aspect of the present invention, there is provided the high frequency measuring substrate according to the first aspect, wherein the radial length of the connecting conductor is the shortest radial length. By setting the radial-shaped conductor to have half or less of its radial length, the semi-circular, fan-shaped or fan-shaped circumferential charge density distribution in a substantially radial stub-shaped equivalent ground conductor becomes uniform. Since it occurs at a frequency on the lower frequency side as compared with the case where it is configured with the radial shape conductor of, the resonance frequency can be more effectively moved to the lower frequency side of the transmission frequency band with low loss. As a result, the low-loss transmission frequency band is expanded, so
It was possible to obtain a substrate for high frequency measurement, which has low loss characteristics in a wide band.

According to a third aspect of the present invention, there is provided a high frequency measurement substrate according to the first or second aspect, wherein a plurality of radial conductors are located in a central radial shape. Since the conductor and the outer radial conductor arranged on both sides of the central radial conductor and having a central angle of about ½ of the central angle of the central radial conductor, a substantially radial stub shape The semi-circular, fan-shaped or fan-shaped circumferential charge density distribution in the equivalent ground conductor of is generated at a frequency on the lower frequency side compared to the case where it is composed of a single radial-shaped conductor. Therefore, the resonance frequency can be more effectively moved to the low frequency side of the low-loss transmission frequency band, and as a result, the low-loss transmission frequency band is expanded, so that the wide band It could be a substrate for high-frequency measuring with low loss characteristics.

Further, according to the high frequency measuring substrate of the present invention, there is no need for a highly accurate substrate processing step unlike the case of the conventional high frequency measuring substrate using through conductors such as through holes and via holes. Therefore, it becomes possible to easily and inexpensively provide a high-frequency measurement substrate capable of highly accurate measurement.

As described above, according to the present invention, in the high frequency measurement board using the radial stub as an equivalent ground, the resonance frequency of the radial stub is moved to the low frequency side to widen the low loss transmission frequency band. It was possible to provide the high frequency measurement substrate.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of an embodiment of a high frequency measurement substrate of the present invention.

FIG. 2 is a plan view showing another example of the embodiment of the high frequency measurement substrate of the present invention.

FIG. 3 is a plan view showing still another example of the embodiment of the high frequency measurement substrate of the present invention.

FIG. 4 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 5 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 6 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 7 is a plan view showing an example of a conventional high-frequency measurement substrate as a comparative example.

FIG. 8 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 9 is a plan view showing an example of a conventional high-frequency measurement substrate.

FIG. 10 is a diagram showing a reflection characteristic with respect to frequency in a high frequency measurement substrate.

FIG. 11 is a diagram showing transmission characteristics with respect to frequency in a high frequency measurement substrate.

FIG. 12 is a plan view showing an example of a conventional high-frequency measurement substrate.

FIG. 13 is a diagram showing transmission characteristics with respect to frequency in a high-frequency measurement substrate.

FIG. 14 is a plan view showing an example of a conventional high frequency measurement substrate.

FIG. 15 is a plan view showing an example of a radial stub.

[Explanation of symbols]

31, 41, 51 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Dielectric substrates 32, 42, 52 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Signal conductors 34, 34 ″, 44, 44 ″, 54, 54 ″ ・..Radial shaped conductors (outer radial shaped conductors) 34 ', 44', 54 ', ... Radial shaped conductors (center radial shaped conductors) 35, 35', 45, 45 ', 55, 55 '... Connection conductors 36, 46, 56 .................. Equivalent ground conductors

Front page continuation (51) Int.Cl. ⁷ identification code FI H01P 1/00 G01R 31/28 K 5/08 H01L 27/04 T (58) Fields investigated (Int.Cl. ⁷ , DB name) G01R 31 / 28 G01R 1/06 G01R 31/26 H01L 21/822 H01L 27/04 H01P 1/00 H01P 5/08

Claims (3)

(57) [Claims] 1. A ground conductor is formed on substantially the entire lower surface of a dielectric substrate, and a signal conductor of a microstrip line and a substantially radial stub-shaped equivalent ground conductor provided near the tip of the signal conductor are formed on the upper surface. A high-frequency measurement substrate for electrically connecting a signal conductor and a ground conductor of a wafer probe having a coplanar line structure to the signal conductor and the equivalent ground conductor, respectively, wherein the equivalent ground conductor is a center. A high-frequency wave characterized by comprising a plurality of radial-shaped conductors having different radial lengths and arranged in a substantially arcuate shape sharing the same, and a connecting conductor electrically connecting the plurality of radial-shaped conductors. Measurement substrate. 2. The high frequency wave according to claim 1, wherein the radial length of the connection conductor is not more than half the radial length of the radial conductor having the shortest radial length. Measurement substrate. 3. The plurality of radial-shaped conductors are disposed at the center, and the central radial-shaped conductor is disposed on both sides of the central radial-shaped conductor, and the central angle is about half the central angle of the central radial-shaped conductor. 3. The substrate for high frequency measurement according to claim 1 or 2, wherein the outer radial conductor is 1.