JPH0846412A - Resonance circuit board - Google Patents

Abstract

PURPOSE:To combine short stubs for coarse adjustment and for fine adjustment and to widen the variable adjustment range of frequency adjustment by arranging a second ground conductor film to which only a part of the short stub is placed oppositely inside a dielectric member. CONSTITUTION:On both sides of one end of a microstrip line 1, a first short stub 11 and a second short stub 12 are respectively formed. The dielectric member 2 of this resonance circuit board 10 is composed of at least two dielectric layers 21 and 22 and the second ground conductor film 31 is interposed in a part between the layers. The second ground conductor film 31 is formed only at a position corresponding to the second short stub 12 and is arranged so as not to be placed oppositely at least to the first short stub 11. For instance, the coarse adjustment is made possible by cutting off the short stub opposite to a ground conductor film 3 and the fine adjustment is made possible by cutting off the short stub opposite to the second ground conductor film 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonant circuit board used for a high frequency voltage controlled oscillator (VCO) and having a microstrip line.

[0002]

2. Description of the Related Art Conventionally, a high-frequency oscillator, for example, a voltage controlled oscillator (VCO), is shown in FIG.
X is a resonant circuit unit including a microstrip line MSL ₁ , MSL ₂ varicap diode Cv, and capacitors C _{1 to} C ₄ , and Y is an oscillation transistor, a resistor,
N is a negative resistance circuit section including a capacitor, and Z is an amplification circuit section including an amplifying transistor, a microstrip line, a resistor, a capacitor, and the like.

In such a high frequency oscillating device, when a predetermined voltage is applied from the control terminal Vt, the capacitance of the varicap diode Cv in particular changes, whereby a predetermined resonance frequency is obtained. When this and the negative resistance circuit section Y satisfy the oscillation condition and oscillate, the signal is amplified by the amplification circuit section Z and is derived from the output terminal OUT.

In the manufacturing process of such a high-frequency oscillator, the frequency adjustment according to the specifications is performed by adjusting the microstrip line MSL ₁ of the resonance circuit section X.

In such a high-frequency oscillator, the oscillation frequency adjusting method adjusts the line length of the microstrip line MSL ₁ forming the resonance circuit section.

The above-mentioned microstrip line MSL
₁ is formed on a resonant circuit board 60 made of a dielectric substrate as shown in FIG. In FIG. 6, a conductor film 61 (hereinafter referred to as a microstrip line) formed in a linear shape, a U shape, a J shape, or the like on one main surface of a dielectric substrate 62.
And a through-hole conductor 64 connected to the ground conductor film 63 at one end of the microstrip line 61. here,
In order to enable the above frequency adjustment, one end of the microstrip line 61 has a plurality of conductor films 65 cut by laser irradiation, sandblasting, drilling, or the like.
Short stubs 65 composed of a, 65b, ... Are connected, and a predetermined number of conductor films 65a, 65b of the short stub 65 are taken into consideration in consideration of the oscillation frequency of the high-frequency oscillator (resonance frequency at the resonance circuit board level). , Were sequentially cut in the direction of the arrow in the figure.

The substantial length component of the microstrip line 61 changes depending on the disconnection state of the short stubs 65 to 69 connected to the microstrip line 61, which increases the characteristic impedance and lowers the oscillation frequency. Can be done. This short stub 6
The relationship between the number of cuts for sequentially cutting the conductor films 65a, 65b, ... Forming No. 5 and the change in the oscillation frequency is that the oscillation frequency linearly decreases with respect to the number of cuts of the short stub.

[0008]

However, in FIG. 6 described above, the short subdub 65 connected to one end of the microstrip line 61 can only adjust the frequency of a single inclination, so that the frequency adjustment width can be widened, for example. If desired, the number of conductor films of the short stub 65 must be increased, and as a result, the resonant circuit board 60 becomes large.

In order to finely adjust the frequency, the frequency change rate is small, that is, the short stub 6
It is necessary to reduce the shape of the conductor films 65a, 65b ... However, the conductor film 65 of the short stub 65
In order to accurately form the shapes of a, 65b, ..., There are restrictions due to the printing accuracy of the conductive paste at the time of formation, and the cutting should be performed with great care when cutting with a cutting means such as laser irradiation. There is a need.

The present invention has been devised in view of the above problems, and an object thereof is to adjust a variable adjustment range by performing a frequency adjustment by combining a short stub for coarse adjustment and a short stub for fine adjustment. It is an object of the present invention to provide a resonant circuit board which can be widened and enables fine adjustment within that range, and in which the short stub for fine adjustment can be formed and cut very easily.

[0011]

The resonance circuit board of the present invention has a microstrip line having a short stub for impedance adjustment connected to the front surface of a dielectric member, and a microstrip line on the back surface facing the microstrip line and having a microstrip line. A resonance circuit board having a ground conductor film connected to one end of a strip line, wherein a second ground conductor film is arranged in the dielectric member so that only a part of the short stub faces the second ground conductor film. .

[0012]

According to the present invention, the substantial line length of the microstrip line can be adjusted by cutting an arbitrary number of short stubs connected to a part of the microstrip line.

Focusing only on the short stub, the short stub (coarse adjustment short stub) facing the ground conductor film and the short stub facing the second ground conductor film disposed between the dielectric members ( Fine adjustment short stubs) are installed side by side.

That is, since the space Δt between the coarse adjustment short stub and the ground conductor film and the space Δt ₁ between the fine adjustment short stub and the second ground conductor film are different,
The influence of the cutting of these short stubs on the actual line length of the microstrip line is different.

Thus, for example, by cutting the short stub facing the ground conductor film, the inclination of the decrease of the resonance frequency becomes large, and as a result, the rough adjustment becomes possible and the short circuit facing the second ground conductor film becomes possible. By cutting the stub, the slope of the decrease in the resonance frequency is reduced, and as a result, fine adjustment is possible.

As described above, the frequency adjustment range can be increased by combining the coarse adjustment short stub and the fine adjustment short stub, and depending on the number of sequentially cut conductor films forming the coarse adjustment short stub and the fine adjustment short stub,
It enables quick and highly accurate frequency adjustment.

Moreover, as described above, the influence of the adjustment on the microstrip line does not substantially depend on the shape of the short stub on the surface of the substrate, so that the pattern that can form the short stub stably and the short stub can be stabilized. Since both short stubs can be formed in a pattern that can be cut in a uniform manner, and both short stubs can be formed in, for example, the same pattern, an adjustment error due to printing variations is reduced, and stable and easy cutting processing can be performed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A resonance circuit board of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial plan view of a resonance circuit board of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. still,
This resonance circuit board is used as the resonance circuit unit X of the typical high frequency generator shown in FIG. 5, and in FIGS. 1 and 2, only the microstrip line MSL ₁ is shown. Microstrip line MSL ₂ constituting the resonance circuit section X, various electronic components such as varicap diode Cv, capacitors C _{1 to} C ₄
Are omitted.

In FIGS. 1 and 2, 10 is a resonant circuit substrate, 1 is a conductor film of the microstrip line MSL ₁ (hereinafter, simply referred to as microstrip line), 11 is a first short stub, and 12 is a second short stub. Short stub,
Reference numeral 2 is a dielectric member, 3 is a ground conductor film, 31 is a second ground conductor film, and 4 is a through-hole conductor.

The microstrip line 1 is formed by printing and baking a thick-film conductive paste on one main surface of the resonance circuit board 10, and its shape is a straight line having a predetermined width and a predetermined length. Further, a plurality of conductor films 11a, 11b, ... Are provided on both sides of one end of the microstrip line 1.
The first short stub 11 is formed by connecting in a ladder shape, and the second short stub 12 is formed by connecting a plurality of conductor films 12a, 12b ... In a ladder shape. . The short stubs 11 and 12 are formed simultaneously with the microstrip line 1.

The dielectric member 2 of the resonance circuit board 10 is composed of at least two dielectric layers 21 and 22, and a second ground conductor film 31 is interposed in a part between the layers. The second ground conductor film 31 is the second short stub 1 described above.
It is formed only at a position corresponding to 2, and is arranged so as not to face at least the first short stub 11.

Here, examples of the material of the dielectric layers 21 and 22 include a dielectric material such as alumina and barium titanate, or a material obtained by mixing these dielectric materials with a glass component. The material of the second ground conductor film 31 is Ag.
Examples thereof include a system (Ag simple substance, Ag alloy such as Ag-Pd), a Cu-based low resistance material, a high melting point material such as molybdenum and tungsten.

The ground conductor 3 includes at least a first short stub 11 on the other main surface side of the dielectric member 2, and is formed over a relatively wide area so as to face the microstrip line 1. There is. The ground conductor film 3 is A
Examples thereof include g-based materials (Ag simple substance, Ag alloys such as Ag-Pd) and Cu-based low resistance materials.

The connection between the one end side of the microstrip line 1 and the ground conductor film 3 and the connection between the ground conductor film 3 and the second ground conductor film 31 are, for example, the microstrip line 1
Are connected to each other by a through-hole conductor 4 formed at one end side of the. As a means for connecting the one end side of the microstrip line 1 and the ground conductor film 3, in addition to the through hole conductor 4, the end surface of the dielectric member 2 may be used for connection by a connection conductor.

The other end of the microstrip line 1 is connected to the microstrip line MSL ₂ , the varicap diode Cv, the capacitors C _{1 to} C ₄ shown in FIG.

A feature of the present invention is that both short stubs 11 and 12 for adjusting the substantial line length of the microstrip line 1 are formed on the dielectric member 2, and The first short stub 11 faces the ground conductor film 3, the second short stub 12 faces the second ground conductor 31, and a dielectric member between the first short stub 11 and the ground conductor 3. The thickness Δt of 2 (corresponding to the sum of the layer thicknesses of the dielectric layers 21 and 22) and the dielectric member 2 between the second short stub 12 and the second ground conductor 31.
Is different from the thickness Δt ₁ (layer thickness of the dielectric layer 21).

Therefore, in order to adjust the resonance frequency of the microstrip line 1 of the resonance circuit board 10 (oscillation frequency in the oscillation device having the resonance circuit board 10) to a predetermined value, the conductor film 11a of the short stub 11 is adjusted. 1
1b ... As indicated by an arrow B in FIG.
One conductor film is sequentially cut from a to 11h.

Similarly, the conductor films 12a, 12b, ... Of the short stub 12 are sequentially cut from the conductor films 12a to 12h one conductor film at a time, as shown by an arrow C in FIG.

For example, the conductor film 11 to be cut first
a and 12a are cut, the substantial line length of the microstrip line 1 is changed, the resonance frequency is changed, and the oscillation frequency is adjusted. The impact will be different.

This is compared with the distance Δt between the short stub 11 and the opposing ground conductor film 3 and the distance Δ between the short stub 12 and the opposing second ground conductor film 31.
Since the width is narrowed to t ₁ , even if the short stubs 11 and 12 having substantially the same pattern on the surface of the dielectric member 2, the change amount of the characteristic impedance is reduced with respect to the conductor films 12a and 12b of the short stub 12. This is because the change due to the sequential disconnection of ...

In the method of manufacturing the resonant circuit board 10 as described above, first, the dielectric member 2 on which the second ground conductor film 31 is arranged is formed.

Specifically, a dielectric green sheet that will be the dielectric layers 21 and 22 that compose the dielectric member 2 is prepared, and for example, a second dielectric green sheet will be formed on the surface of the dielectric green sheet that will be the dielectric layer 22. A conductor film to be the ground conductor film 31 is formed by printing and drying a conductive paste, and then the dielectric layer 2 is formed.
The dielectric green sheet which becomes 1 and the dielectric green sheet which becomes the dielectric layer 22 are joined. In addition, even if a through hole to be the through-hole conductor 4 is formed in the dielectric green sheet in advance and the through hole is filled with a conductive paste when, for example, a conductor film to be the second ground conductor film 31 is printed. I do not care. Furthermore, a laminated body may be formed using a large green sheet from which a plurality of resonant circuit boards 10 can be extracted, and then dividing grooves may be formed vertically and horizontally so as to be divided into a predetermined size.

Next, the above-mentioned unfired laminate is fired in a predetermined atmosphere.

Next, firing treatment is performed, and the microstrip line 1, short stub 11,
The conductive film 12 is formed by screen printing, drying, and baking using a conductive paste containing a low-resistance metal material powder such as Ag-based or Cu-based, glass frit, for example. Incidentally, when the conductive paste is not filled in the through hole to be the through hole conductor 4, the conductive film is formed on the inner wall of the through hole in this step. Further, in this step, in addition to the microstrip line 1 and the short stubs 11 and 12, wirings and pads (not shown) for joining various electronic components such as capacitors connected to the microstrip line 1 may be formed. it can. Although Ag-based and Cu-based materials are listed as the material of the conductor, a Cu-based material is preferable in consideration of high-frequency characteristics, migration, solder erosion and the like.

Then, a conductor film to be the ground conductor film 3 is formed on the other main surface of the laminated substrate by baking, for example, Ag-based or C-based.
It is formed by screen printing, drying, and baking using a conductive paste containing a low resistance metal material powder such as u-based material and glass frit. When the conductive paste is not filled in the through hole to be the through-hole conductor 4, the conductive film is formed on the inner wall of the through hole from the other main surface also in this step.

Although the above-described microstrip line 1, short stubs 11 and 12 and the ground conductor film 3 are separately baked, they can be simultaneously printed.

Next, in the above-described microstrip line 1, desired resonance characteristics are rarely obtained depending on the printing accuracy of the conductive paste and other conditions. Therefore, a resonance frequency measuring analyzer is connected to the microstrip line 1, and the resonance frequency is adjusted to a predetermined value while measuring the resonance frequency.

Specifically, the conductor films 11a and 11 forming the short stubs 11 and 12 are measured while measuring the resonance characteristics.
b ..., 12a, 12b ... are sequentially cut,
It is driven so that it becomes a predetermined resonance frequency. Conductor films 11a, 11b ..., 12a, 1 of the short stubs 11, 12
Since the resonance frequency decreases by sequentially cutting 2b ..., The resonance frequency before adjustment is set to be slightly higher than the desired frequency, and the short stub 1
, 12 conductor films 11a, 11b ..., 12a, 12
By cutting b ...

The cutting method is as follows: conductor films 11a, 11b ..., 12a, 12b ...
Further, as shown by arrows A and B in FIG. 1, the irradiation is sequentially performed with an energy beam such as a laser, and mechanical stress such as sandblasting and drilling.

In this way, electronic components are mounted on each resonant circuit board having the microstrip line 1 whose resonance characteristic is adjusted, and the individual resonant circuit boards 10 are formed along the above-mentioned dividing grooves. The division processing is performed as follows.

The inventor of the present invention sequentially cuts the short stubs 11 and 12 having different intervals Δt and Δt ₁ from the ground conductor films 3 and 31 via the dielectric member 2 by sequentially cutting the microstrips. The influence on the characteristics of the line 1 was investigated. In the measurement, the above-mentioned resonant circuit board was used as an actual oscillation circuit, and the tendency was examined using the oscillation frequency.

FIG. 3 shows that when the conductor films 11a, 11b ... Of the short stub 11 which substantially face the ground conductor film 3 are not cut, only when the conductor film 11a is cut, and further up to the conductor film 11b. FIG. 9 is a characteristic diagram showing a situation of a change in oscillation frequency in the case of disconnection.

Further, FIG. 4 shows that the conductor films 12a, 1a of the short stub 12 that substantially face the second ground conductor film 31.
If 2b ... is not cut, the conductor film 12a
It is a characteristic view showing the situation of the change of the oscillation frequency in the case where only the conductor film 12b is further cut, and the conductor film 12b is further cut.

As can be understood by comparing FIG. 3 and FIG. 4, the conductor films 11a, 11b of the short stub 11 ...
By sequentially disconnecting, the oscillation frequency can be lowered with a relatively large change (large inclination). Further, when the conductor films 12a, 12b, ... Of the short stub 12 are sequentially cut, the oscillation frequency can be lowered with a relatively small change (small inclination).

This is because cutting the short stubs 11 and 12 raises the characteristic impedance and affects the characteristic impedance of the microstrip line 1. However, in the short stub 11 and the short stub 12, grounding is performed. Distances Δt and Δt from the conductors 3 and 31
_The reason that ₁ is different is that the influence of the characteristic impedance is different between the two short stubs 11 and 12.

Therefore, in the adjustment of the microstrip line 1, first, the conductor films 11a, 11b, ... Constituting the short stub 11 are sequentially cut from the direction of the arrow B to bring them closer to a desired oscillation frequency, and then, The conductive films 12a, 12b, ... Constituting the short stub 12 are indicated by arrows C.
Sequentially cut from the direction to match the desired frequency.

That is, the conductor film 11 of the short stub 11
a, 11b ..., Conductor film 12 of short stub 12
Number of cuts a, 12b ... (short stubs 11, 12
The frequency band (frequency variable width) from the frequency in the state where the short stubs 11 and 12 are not cut at all to the frequency where the short stubs 11 and 12 are all cut )
In, extremely fine adjustment is possible.

Further, the short stubs 11 and 12 described above are used.
The degree of influence on the microstrip line 1 in the above is the distance Δt between the short stub 11 and the ground conductor film 3.
(Actually, it depends on the dielectric constant of the dielectric member 2, the facing area, etc.), but the short stub 12 and the second ground conductor film 3
1 is the difference in the distance Δt from 1 and, for example, the conductor films 11 a, 11 b, ... 1 forming the short stubs 11, 12.
The conductor lengths, conductor widths, intervals, etc. of 2a, 12b, ... Can be made the same pattern.

This is a short stub 1 for fine adjustment.
When forming the pattern 2, even if the pattern is formed in consideration of the printing accuracy, there is no error due to the deterioration of the printing accuracy, stable fine adjustment is possible, and the adjustment error can be reduced. Further, since the short stubs 11 and 12 can have the same shape, both the short stubs 11,
12 cutting conditions, control of the cutting means, for example, in the case of laser irradiation, the laser output, scanning speed, the time interval between the first cutting and the next cutting can be made the same, The control of cutting is very easy.

Although the microstrip line is formed in a straight line in the above-mentioned embodiment, it may have any shape.

When it is desired to control the inclination of the resonance frequency of the microstrip line 1 which the short stub 12 exerts, the pattern of the short stub 12 is not changed and the distance Δt between the short stub 12 and the second ground conductor film 31 is changed. ₁
This can be easily done by controlling the. For example, the dielectric layer may have a three-layer structure, and the third ground conductor film may be formed between the layers on the surface side.

Further, 2 corresponding to the second ground conductor film 31
By arranging one ground conductor film between different layers and forming a short stub so as to face the ground conductor film, a short stub for coarse adjustment, a short stub for intermediate adjustment,
Three types of short stubs for fine adjustment can be formed, and finer adjustments can be made.

Further, the short stub 12 is made to face the ground conductor film arranged on the other main surface side of the dielectric member 2, and the short stub 11 and the microstrip line 12 are arranged on the ground conductor film arranged inside the dielectric member 2. You may make it face each other.

[0055]

As described above, according to the present invention, the resonance characteristics of the microstrip line can be roughly adjusted and finely adjusted by cutting an arbitrary number of short stubs composed of a plurality of conductor films. As a result, the frequency adjustment range can be widened, and further, the resonance circuit board can be roughly and finely adjusted within the range.

Moreover, since the short stubs for coarse adjustment and the short stubs for fine adjustment can be formed in substantially the same pattern, it is stable especially when forming the conductor film to be the short stubs for fine adjustment. Since it can be formed with printing accuracy, an error in fine adjustment can be reduced, and cutting can be performed under the most stable cutting conditions.

Further, the inclination of the adjustment degree can be set by the distance between the second ground conductor film arranged on the dielectric member and the short stub, and the resonance circuit can be adjusted efficiently without changing the pattern of the short stub. It becomes the substrate.

[Brief description of drawings]

FIG. 1 is a plan view of a resonant circuit board of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a characteristic diagram showing a change in oscillation frequency when the coarse adjustment short stub is cut.

FIG. 4 is a characteristic diagram showing a change in oscillation frequency when the fine adjustment short stub is cut.

FIG. 5 is a circuit diagram of a typical high frequency oscillator.

FIG. 6 is an external perspective view of a conventional resonant circuit board.

[Explanation of supplementary symbols] 1 ... Microstrip line 11, 12 ... Short stub 2 ... Dielectric member 21, 22 ... Dielectric layer 3 ... Ground conductor film 31 ... Second ground Conductor film

Claims (1)

[Claims] 1. A microstrip line in which a short stub for impedance adjustment is connected to the front surface of a dielectric member, and a ground conductor film facing the microstrip line and connected to one end of the microstrip line is formed on the back surface. 2. The resonant circuit board according to claim 1, wherein a second ground conductor film is arranged in the dielectric member so that only a part of the short stub faces the second ground conductor film.