JPH0613808A - Frequency control method for oscillator - Google Patents

Abstract

PURPOSE:To increase the controllable range of the oscillator frequency, to reduce the tolerance of the parts forming a resonance circuit, and to prevent the occurrence of defects due to the excessive control of the oscillator frequency. CONSTITUTION:An inductor conductor 11 provided on the surface of an insulated substrate forming a part of a multi-layer structure strip line inductor 4 has an approximately L shape and also includes an open stub part 11a at a part of the side connected to a through hole 12. Then a part of the conductor 11 is eliminated so that the line length of the conductor 11 is increased or the area of the part 11a of reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of adjusting the oscillation frequency of an oscillator using a multilayer stripline inductor as an inductor of an LC resonance circuit.

[0002]

2. Description of the Related Art An example of a structure near an LC resonance circuit of this type of oscillator is shown in FIGS. In this example, the multilayer structure stripline inductor 4 having the following configuration is
It is used as an inductor in an LC resonance circuit.

That is, in this multilayer stripline inductor 4, inductor conductors 8 and 10 are formed inside and on the surface of an insulating substrate 6, both inductor conductors 8 and 10 are connected to each other through a through hole 12, and the insulating substrate 6 is also used. Ground electrodes 14 and 16 are formed on the inside and the back surface of the above so as to sandwich the inside inductor conductor 8 with the member of the insulating substrate 6 interposed therebetween. Both ground electrodes 14 and 16 are connected to each other by a through hole 18. Both ground electrodes 14 and 16 are usually formed on almost the entire area of the insulating substrate 6.

On the surface of the insulating substrate 6, the components that constitute the oscillator together with the above-mentioned multilayer structure stripline inductor 4 are mounted. For example, at the end of the front surface inductor conductor 10 opposite to the through hole 12, a capacitor 20 that constitutes an LC resonance circuit together with the multilayer structure stripline inductor 4 and this LC resonance circuit are connected to an oscillation transistor (not shown) or the like. The capacitor 21 is connected. Further, when the oscillator is a voltage controlled oscillator (VCO), a variable capacitance diode 24 (not shown in FIG. 6, see FIG. 8) is connected via the capacitor 22. A circuit diagram of such a structure is shown in FIG. The variable capacitance diode 24 is for controlling the oscillation frequency by a control voltage.

In such an oscillator, there are variations in characteristics of components such as the multilayer structure stripline inductor 4 and the capacitors 20 and 22 which form the LC resonance circuit.
It is necessary to adjust the oscillation frequency.

Conventionally, as a method, a part of the inductor conductor 10 on the surface of the insulating substrate 6 is removed by a router or a laser beam in a comb shape as shown in FIG. 6 (26 indicates the removed portion). In this way, the inductance component is increased by increasing the line length of the inductor conductor 10. In this case, the overall inductance of the multilayer stripline inductor 4 is originally set to be small.

[0007]

However, in the conventional frequency adjusting method as described above, the frequency can not be increased even though the inductance can be decreased by increasing the inductance, so that the oscillation frequency can be adjusted. Since the range is narrow and the adjustable range is narrow, the tolerance for the characteristics (values of capacitance etc.) of parts such as capacitors that make up the resonance circuit is strict, which increases the cost of parts and is due to excessive removal of the adjustment target value. There is a problem that a non-reproducible defect may occur.

Therefore, the main object of the present invention is to provide a frequency adjusting method capable of expanding the adjustable range of the oscillation frequency, relaxing the tolerance of the components constituting the resonance circuit, and preventing the occurrence of defects due to excessive adjustment. And

[0009]

In order to achieve the above object, the frequency adjusting method of the present invention has an open stub portion integrally formed with a portion connected to a through hole of an inductor conductor formed on the surface of an insulating substrate as described above. Is provided, and a part of such an inductor conductor is removed so as to increase the line length or reduce the area of the open stub portion.

[0010]

According to the above method, when a part of the inductor conductor having the open stub portion formed on the surface of the insulating substrate is removed so as to increase the line length, the inductance of the inductor conductor increases, so that the oscillation frequency is reduced. Can be lowered.

Further, when a part of the inductor conductor is removed so as to reduce the area of the open stub portion,
Since the stray capacitance between the inductor conductor and the ground electrode inside the insulating substrate is reduced, the oscillation frequency can be increased.

[0012]

1 is a plan view showing an example of a structure near an LC resonance circuit of an oscillator for implementing a frequency adjusting method according to the present invention. FIG. 2 is a sectional view taken along the line AA of FIG. The same or corresponding portions as those of the conventional example shown in FIGS. 6 and 7 are designated by the same reference numerals, and the differences from the conventional example will be mainly described below.

In the multilayer stripline inductor 4 of this example, the following inductor conductor 11 is formed on the surface of the insulating substrate 6 in place of the conventional inductor conductor 10. That is, the inductor conductor 11 is substantially L-shaped, and the open stub portion 11a is integrally provided on the side portion of the inductor conductor 11 connected to the through hole 12. At the end portion of the inductor conductor 11 opposite to the through hole 12, for example, the capacitor 20 as described above is provided.
~ 22 are installed and connected. The equivalent circuit around the LC resonance circuit of the oscillator in that case is as shown in FIG.

An example of a method of adjusting the oscillation frequency of an oscillator using such a multilayer stripline inductor 4 is as follows.

To reduce the oscillation frequency, for example, as shown in FIG. 3, the corner portion of the inductor conductor 11 which is bent in an L shape is removed in a slit shape toward the open stub portion 11a side (28 is removed). Part). By doing so, the inductor conductor 11 has a shape that bypasses the removed portion 28, so that the line length becomes long and the inductance component increases. Therefore, the oscillation frequency can be lowered.

To increase the oscillation frequency, for example, as shown in FIG. 4, the open stub portion 11 of the inductor conductor 11 is used.
The part of the tip of a is removed (30 indicates the removed part). By doing so, the total area of the inductor conductor 11 is reduced, and accordingly, the stray capacitance between the inductor conductor 11 and the ground electrode 14 inside the insulating substrate is reduced. Therefore, the oscillation frequency can be increased.

In order to remove a part of the inductor conductor 11 as described above, it may be mechanically cut by, for example, a router or may be heated and melted by a laser beam.

According to the method as described above, since the oscillation frequency can be adjusted in the vertical direction, the adjustable range is expanded. Further, as a result, the tolerance of the components forming the resonance circuit is relaxed, so that it is possible to reduce the cost of the components and eventually the oscillator. Furthermore, since the oscillation frequency can be adjusted in the vertical direction, the occurrence of defects due to excessive adjustment as in the conventional case is reduced.

The inductor conductor 11 is not formed in an L shape as in the above example, but is formed in a strip shape as shown in FIG. 5, for example, and an open stub portion 11a is integrally provided at a portion connected to the through hole 12. You may stay. Also in the case of this example, a part of the inductor conductor 11 is removed, for example, in a comb shape between the through hole 12 and the part to which the capacitors 20 to 22 are connected, thereby increasing the inductance and increasing the oscillation frequency. Can be lowered. Further, by removing an appropriate part of the open stub portion 11a, the stray capacitance can be reduced and the oscillation frequency can be increased. As a result, the effects as described above can be obtained.

In the case of the example of FIG. 1, however, as is clear from comparison with the example of FIG. 5, the size of the inductor conductor 11 as a whole is reduced while the variable range of the line length (that is, the inductance). And the variable range of the area of the open stub portion 11a (that is, the variable range of the stray capacitance), thereby increasing the adjustable range of the oscillation frequency.

The planar shape of the inductor conductor 8 inside the insulating substrate 6 is not limited to the U-shape as in the above example, but may be arbitrary and may be determined according to the required total inductance and the like. . For example, when the required total inductance is small, it may be a straight line shape, and conversely, when it is large, it may be a spiral shape.

In the above description, the voltage controlled oscillator including the variable capacitance diode in the resonance circuit has been described as an example of the oscillator. However, the present invention can be applied to a normal oscillator not including such a variable capacitance diode. Can be applied.

[0023]

As described above, according to the present invention, since the oscillation frequency can be adjusted in the vertical direction, the adjustable range is expanded. Further, as a result, the tolerance of the components forming the resonance circuit is relaxed, so that it is possible to reduce the cost of the components and eventually the oscillator. Furthermore, since the oscillation frequency can be adjusted in the vertical direction, the occurrence of defects due to excessive adjustment as in the conventional case is reduced.

When the inductor conductor on the surface of the insulating substrate is formed into a substantially L-shape and an open stub portion is integrally provided on the side of the inductor conductor which is connected to the through hole, the size of the entire inductor conductor is reduced. It is possible to obtain a further effect that the adjustable range of the oscillating frequency can be increased while reducing the value.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a structure near an LC resonance circuit of an oscillator that implements a frequency adjusting method according to the present invention.

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

FIG. 3 is a diagram showing an example of a method of removing a part of the inductor conductor on the surface of the insulating substrate of FIG.

FIG. 4 is a diagram showing another example of a method for removing a part of the inductor conductor on the surface of the insulating substrate of FIG.

FIG. 5 is a plan view showing another example of the inductor conductor on the surface of the insulating substrate.

FIG. 6 is an LC of an oscillator that implements a conventional frequency adjustment method.
It is a figure which shows an example of the structure of a resonance circuit vicinity.

7 is a cross-sectional view taken along the line BB of FIG.

FIG. 8 is a circuit diagram showing an example around an LC resonance circuit of an oscillator.

[Explanation of symbols]

 4 Multi-layered stripline inductor 6 Insulating substrate 8 and 11 Inductor conductor 11a Open stub 12 Through hole 14 and 16 Ground electrode 28 and 30 Removed part

Claims (2)

[Claims] 1. An inductor conductor is formed inside and on the surface of an insulating substrate, both inductor conductors are connected to each other by through holes, and a ground electrode is sandwiched between the inside and the back of the insulating substrate so as to sandwich the inductor conductor inside. In a method of adjusting the oscillation frequency of an oscillator used as an inductor of an LC resonant circuit, a multilayer stripline inductor formed by The frequency adjustment of the oscillator is characterized in that an open stub is provided in advance and a part of such an inductor conductor is removed so as to increase the line length or reduce the area of the open stub. Method. 2. The inductor conductor formed on the surface of the insulating substrate is formed into a substantially L shape, and the open stub portion is integrally provided at a side portion of the inductor conductor which is connected to the through hole. 1. The oscillator frequency adjustment method according to 1.