JPH0222902A - Adjusting method for resonance frequency - Google Patents

Abstract

PURPOSE:To adjust the oscillation frequency and the filter characteristic with a good yield without degrading characteristics by cutting or notching a trimming pattern to reduce the electrostatic capacity or increase the inductance. CONSTITUTION:When a trimming device 8 is driven in the direction of an arrow A, a trimming pattern 10 is shaved to reduce the area of the trimming pattern 10, and the electrostatic capacity of a capacitor part is reduced to raise the frequency. When the device 8 is driven in the direction of an arrow B, the trimming pattern 10 is notched to extend the route of an inductance part from the inner conductor of a dielectric coaxial resonator 1 to the electrode of a capacitor 4 which is a part of a resonance circuit, and the inductance of the trimming pattern 10 is increased to reduce the frequency. Thus, it is unnecessary to design a parallel plane capacitor in a size larger than required, and desired oscillation frequency and filter characteristic are obtained by trimming.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resonant frequency adjustment method for adjusting the oscillation frequency and filter characteristics of a resonant circuit using a dielectric coaxial resonator.

[Prior Art] Fig. 2(a) shows the configuration of a resonant circuit using a dielectric coaxial resonator, and Fig. 2(b) shows the dielectric coaxial resonator shown in Fig. 2(a). is equivalently replaced by an LC parallel resonant circuit <It is also possible to replace it with an LC series resonant circuit). In each figure, (1) is a dielectric coaxial resonator, and (2) is a capacitor. The variable capacitor (3) shows the LC parallel resonant circuit.

The first method to adjust the oscillation frequency and filter characteristics in a resonant circuit as shown in Figure 2 is to change the length of the dielectric coaxial resonator (1) to adjust the resonant frequency of the resonator itself. There is a way to do it. This method is illustrated in Figure 2 (b), for example.
), this is the same as changing the inductance and capacitance of the LC parallel resonant circuit (3) itself, but changing the length of the resonator while it is mounted on the circuit board. is difficult and not suitable for actual manufacturing.

The second method is to connect a capacitor (2) whose capacitance can be changed in parallel or in series with the dielectric coaxial resonator (1), as shown in Figure 2, and to There is a way to adjust by changing the capacity.

One way to adjust the capacitance of the capacitor (2) is to use a trimmer capacitor, which is a discrete component, but trimmer capacitors have large losses and have moving parts that cause them to vibrate. It has the disadvantage of being weak against

Another method is to use a trimming device to trim a part of the pattern of a parallel plate capacitor formed on a circuit board.

Fig. 3 is a block diagram for explaining the method of using this conventional trimming device. ) is the circuit board, (6) is the control device, (7) is the measuring device, (8) is the trimming device, (9) is the circuit board (5
) It is a parallel plate capacitor in which the pattern formed on the top and the pattern on the back side serve as electrodes.

In the method shown in Fig. 3, the oscillation frequency, filter characteristics, etc. are actually measured using a measuring device (7), and the control device (6) drives the trimming device (8) based on the measured values, thereby controlling the parallel plate capacitor. (9) is adjusted to obtain the desired oscillation frequency and filter characteristics.

[Problems to be Solved by the Invention] In the conventional trimming method as described above, it is possible to trim only in the direction of reducing the electrode area of the parallel plate capacitor and reducing the capacitance. It can only be changed in the direction of increasing.

Therefore, in reality, the resonant frequency of the circuit is designed to be lower than the desired frequency in the initial design, and the resonant frequency is adjusted by trimming to raise the resonant frequency. cannot exceed the desired frequency, so the difference between the design value and the desired frequency is
Since it is necessary to allow a sufficient margin for the maximum deviation, it is necessary to design a large parallel plate capacitor, and the loss of the capacitor may not be negligible, and trimming is necessary. There were problems in that it took time to make adjustments and the performance deteriorated.

This invention was made to solve this problem, and aims to provide a method for adjusting the resonance frequency that allows desired oscillation frequency and filter characteristics to be obtained by trimming without the need to design a parallel plate capacitor unnecessarily large. The purpose is

[Means for Solving the Problems] The resonant frequency adjustment method according to the present invention assumes two patterns on a parallel plate on a circuit board: a pattern that provides a capacitor function and a pattern that provides a coil function. Then, by cutting or making incisions in these patterns, the capacitance of this parallel plate can be reduced to adjust the circuit frequency to a higher direction, or the inductance can be increased to lower the circuit frequency. It is designed so that it can be adjusted to

[Function] In this invention, by cutting or making cuts in the trimming pattern, capacitance can be reduced or inductance can be increased, so the parallel plate formed on the circuit board can be used more than necessary. There is no need for a large design.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram showing an embodiment of the present invention. In the figure, the same reference numerals as in FIG. This trimming pattern is assumed to have a coil function, and the part to which one end of the internal conductor of the dielectric coaxial resonator (1) is connected is the inductance part of this trimming pattern. The part that is continuous with the parallel plate ground conductor and where a capacitance is formed is the capacitor part.

Next, an adjustment method according to the present invention will be explained. While actually measuring the oscillation frequency, filter characteristics, etc. using the measuring device (7), the trimming device (8) is driven in either direction of the arrow (A) or (B) in Fig. 1 based on the results. is determined by the control device (6).

Here, when the trimming device (8) is driven in the direction of the arrow (A), the trimming pattern (10) is scraped off, the area of the trimming pattern (10) is reduced, the capacitance of the capacitor part is reduced, and the frequency When driven in the direction of arrow (B), cuts are made in the trimming pattern (10) to form a dielectric coaxial resonator (
1) From the internal conductor of the capacitor (
4) Lengthen the path of the inductance part to the electrode,
An operation is performed to increase the inductance of the trimming pattern (10) and lower the frequency. Further, in order to cause the trimming device (8) to perform such operations, the control device (6) replaces the nozzle of the trimming device (8), adjusts the power, etc.

As described above, in this invention, the trimming device (8)
The desired frequency can be adjusted by trimming in the direction of arrow (A) to increase the frequency, or by trimming in the direction of arrow (B) to lower the frequency.

In the above embodiment, a parallel plate capacitor is used for the trimming pattern (10), but the present invention is not limited to this, and the same implementation can be made using a multilayer structure capacitor or an interdigital capacitor.

Furthermore, the capacitor (4) that forms part of the resonant circuit shown in FIGS. 1 and 3 can be replaced with a coil, and the same implementation can be achieved.

[Effects of the Invention] As explained above, the present invention can reduce capacitance or increase inductance by cutting or making cuts in the trimming pattern, so it is possible to reduce capacitance or increase inductance. There is no need to design the parallel plate to be larger than necessary, and the resonant frequency of the circuit can be adjusted in the higher or lower direction, so the oscillation frequency and filter characteristics can be adjusted with high yield without deteriorating the characteristics. It has the effect of being able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2(a) is a diagram showing the configuration of a resonant circuit using a dielectric coaxial resonator, and FIG. 2(b) is an equivalent circuit thereof. FIG. 3 is a block diagram for explaining a conventional method. (1) is a dielectric coaxial resonator, (4) is a capacitor that is part of the resonant circuit, (5) is a circuit board, (6) is a control device, <7) is a measuring device, and (8) is a trimming device, (10
) is a trimming pattern. In addition, the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A method for adjusting the resonant frequency of a resonant circuit having a dielectric coaxial resonator and a circuit pattern for adjusting the resonant frequency, wherein one end of the internal conductor of the dielectric coaxial resonator is connected to the circuit pattern. The connected part is an inductance part, and the part that is continuous with this inductance part and forms a capacitance with a ground conductor is a capacitor part, and by making a cut in the inductance part of the circuit pattern, the inductance of the inductance part can be changed. A method for adjusting a resonant frequency, the method comprising: increasing the capacitance of the capacitor portion of the circuit pattern by increasing the area of the circuit pattern of the capacitor portion of the circuit pattern;