JPH05211404A - Resonance frequency adjustment method for strip line type resonator - Google Patents

Abstract

PURPOSE:To easily and exactly obtain an object resonance frequency by eliminating a part of a strip line opposite to a strip line. CONSTITUTION:Part of a ground conductor 2 opposite to strip conductors 3, 4 via a dielectric base is eliminated, then the characteristic impedance is changed and the resonance frequency is changed. That is, when the ground conductor eliminating part 7(8) is provided between a feeding point P1 and another point P2 of the ground conductors 3, 4, the resonance frequency is reduced from an initial value and when the ground conductor eliminating part 7(8) is provided between the feeding point P1 and the point P0 of the ground conductors 3, 4, the resonance frequency is increased from an initial value. Thus, when the resonance frequency is higher than an object frequency, the ground conductor eliminating part 7(8) is provided between the feeding pint P1 and the other point P2. When the resonance frequency is lower than an object frequency, the ground conductor eliminating part 7(8) is formed between the feeding point PI and the point P0 of the ground conductors 3, 4.

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 resonance frequency of a stripline resonator having a dielectric substrate, a strip conductor and a ground conductor.

[0002]

2. Description of the Related Art A 1/4 wavelength strip conductor (microstrip line) is provided on the surface of a dielectric substrate, a ground conductor (earth conductor) is provided on the back surface of the dielectric substrate, and one end of the strip conductor is opened. A stripline resonator having a structure in which an end is connected to a ground conductor is used in the field of high frequency circuits. The resonance frequency of this stripline resonator is determined by the length of the stripline conductor and the relative permittivity of the dielectric substrate. Therefore, in the past, the stripline conductor was made longer so that it resonated at a frequency lower than the target resonance frequency, and then the stripline conductor was cut to shorten the length so that the desired resonance frequency could be obtained. ..

[0003]

According to the conventional method of adjusting the resonance frequency, the length of the strip conductor can be shortened to raise the resonance frequency, but it cannot be lowered. Further, it may be impossible or difficult to scrape the strip conductor after completion.

Therefore, an object of the present invention is to provide a method of adjusting the resonance frequency of a stripline type resonator (including a filter) capable of lowering the resonance frequency.

[0005]

The present invention for achieving the above object provides a dielectric substrate, a ground conductor formed on one main surface of the dielectric substrate, and the other main surface of the dielectric substrate. A strip conductor formed on a surface, one end of the strip conductor is opened, and the other end of the strip conductor is connected to the ground conductor. The present invention relates to a method for adjusting a resonance frequency of a stripline type resonator, wherein a part of the ground conductor facing the strip conductor is removed. As described in claim 2, a feeding point is provided between one end and the other end of the strip conductor, and a part of the ground conductor facing between the feeding point and the one end or between the feeding point and the other end is provided. It is desirable to remove one or both of a part of the ground conductor facing each other and adjust the resonance frequency.

[0006]

ACTION AND EFFECTS The applicant of the present application has found that when a part of the ground conductor (earth conductor) facing the strip conductor via the dielectric substrate is removed, the characteristic impedance changes and the resonance frequency changes. That is, when a part of the ground conductor facing between the feeding point of the strip conductor and the connection end to the ground conductor is removed, the resonance frequency is lowered. Therefore, it is possible to accurately obtain the desired resonance frequency by combining the method of adjusting the resonance frequency by shortening the length of the strip conductor and the method of adjusting the resonance frequency by removing the ground conductor according to the present invention. become. Further, if the ground conductor is exposed even after the laminated structure or after the resonator is incorporated in the circuit device, the resonance frequency can be adjusted. Claim 2
By arranging the feeding point between one end and the other end of the strip conductor as shown in, it is possible to both adjust the resonance frequency by lowering it and increase it by removing the ground conductor, and easily obtain the desired resonance frequency. be able to.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A filter composed of a TEM mode stripline resonator and a method of adjusting a resonance frequency according to an embodiment of the present invention will be described with reference to FIGS.

1 and 2 show a TEM mode stripline resonator or filter before adjustment. This filter includes a dielectric substrate 1, a ground conductor 2 formed on the entire back surface (one main surface), and a quarter wavelength of a fundamental wave formed on the front surface (the other main surface) in a band shape. The first and second strip conductors 3 and 4, and the external circuit connection terminal 5,
It consists of 6 and. The dielectric substrate 1 is composed of a dielectric ceramic substrate having a relative permittivity of 88 and a thickness of 0.8 mm. The strip conductors 3 and 4 are formed to have a width of 0.2 mm.
a is opened, and the other ends 3b and 4b are connected to the ground conductor 2 through the side surface of the dielectric substrate 1. Connection terminals (tap lines) 5 and 6 are connected to the feeding points between the one ends 3a and 4a and the other ends 3b and 4b of the strip conductors 3 and 4, respectively. The pair of strip conductors 3 and 4 are closely arranged in parallel with each other so as to be coupled to each other. The ground conductor 2, the strip conductors 3 and 4, and the connection terminals 5 and 6 are made of a metal conductor film formed by applying a silver (Ag) paste and baking it.

When the stripline filter shown in FIG. 1 is used, the connection terminals 5 and 6 are connected to the high frequency signal transmission line via a coupling capacitor (not shown), and the ground conductor 2 is connected to the ground. As a result, a bandpass filter action is produced by mutual coupling of two 1/4 wavelength type resonators based on the first and second strip conductors 3 and 4.

The dielectric substrate 1 is made of porcelain, and it is difficult to form it so as to have a desired thickness and relative permittivity. Also, it is difficult to form the strip conductors 3 and 4 in a desired size. Therefore, it is difficult to obtain the desired resonance frequency and bandpass filter characteristics. When the resonance frequency is higher than the target, as shown in FIG. 3, a part of the ground conductor 2 facing between the feeding point P1 of the strip conductors 3 and 4 and the other end point P2 is deleted to remove the ground conductor 7, 8 is formed.

When the width W of the ground conductor removed portions 7 and 8 is changed, the resonance frequency f0 changes as shown in FIG. That is, the resonance frequency f1 decreases as the width W increases.

The distance L from the position P0 of the one ends 3a, 4a of the strip conductors 3, 4 to the ground conductor removed portions 7, 8
When is changed, the resonance frequency changes as shown in FIG. That is, the ground conductor removed portions 7 and 8 are connected to the feeding point P.
If it is provided between 1 and the other end point P2 of the strip conductors 3 and 4, the resonance frequency f0 becomes lower than the initial value, and the ground conductor removed portions 7 and 8 are connected to the feeding point P1 and the strip conductor 3,
The resonance frequency f0 becomes higher than the initial value when it is provided between one end (open end) position P0 of No. 4 and P0. Therefore, when the resonance frequency is higher than the target, the ground conductor removed portions 7 and 8 are provided between the feeding point P1 and the other end point P2 as described above.
To provide. At this time, the positions and widths W of the ground conductor removed portions 7 and 8 are determined according to the amount of correction (adjustment) of the resonance frequency.

When the resonance frequency is lower than the target value,
The ground conductor removed portions 7 and 8 are formed so as to correspond between the feeding point P1 and one end positions P0 of the strip conductors 3 and 4, as shown in FIG. Since increasing the resonance frequency f0 can also be achieved by removing the ends 3a, 4a of the strip conductors 3, 4, the strip conductors 3, 4 are
The resonance frequency may be adjusted by using both the method of shortening and the method of forming the ground conductor removed portions 7 and 8 of FIG.

As described above, according to this embodiment, both the adjustment for lowering the resonance frequency and the adjustment for raising the resonance frequency are possible, and the target resonance frequency can be easily and accurately obtained. Further, since the resonance frequency is adjusted by deleting the ground conductor 2, another dielectric substrate, as indicated by a broken line in FIG. 2, is provided on the surface side of the dielectric substrate 1 on which the strip conductors 3 and 4 are provided. Even after laminating 1a and forming the ground conductor 2a on this surface, the resonance frequency can be easily adjusted.

[0015]

MODIFICATION The present invention is not limited to the above-described embodiments, and the following modifications are possible, for example. (1) The connection conductors 5 and 6 may be opposed to the strip conductors 3 and 4 with a gap therebetween without being directly connected to each other, thereby obtaining the input and output coupling capacitances. (2) The connecting conductors 5 and 6 may not be integrally formed on the dielectric substrate 1, but the connecting terminal member or the lead of the coupling capacitor may be coupled to the feeding points of the strip conductors 3 and 4 by soldering or the like. it can. (3) The strip conductors 3 and 4 and the ground conductor 2 can be formed by plating. Further, it is possible to print a conductive paste on a green sheet (porcelain green sheet) to form the strip conductors 3, 4 and the like, and simultaneously fire the porcelain and bake the strip conductors 3, 4 and the like.
Further, it is possible to have a laminated structure as shown by a broken line in FIG. When forming a laminated structure, two green sheets are laminated with the strip conductor sandwiched therebetween, and the green sheet and the strip conductor are simultaneously fired. At this time, the ground conductor can also be fired at the same time. (4) The present invention can be applied to a case where one strip conductor is provided on one dielectric substrate to form one resonator. (5) Another strip conductor may be arranged between the strip conductors 3 and 4 of FIG. 1 to form a combline (comb-shaped) filter. It can also be applied to an interdigital filter. (6) The present invention can be applied to the case where the feeding points in FIG. 1 are the one ends (open ends) 3a, 4a of the strip conductors 3, 4.

[Brief description of drawings]

FIG. 1 is a perspective view showing a resonance frequency of a stripline filter according to an embodiment of the present invention before adjustment.

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

FIG. 3 is a bottom view showing the stripline filter after adjusting the resonance frequency to be low.

FIG. 4 is a sectional view taken along line BB of FIG.

FIG. 5 is a bottom view showing the stripline filter after adjusting the resonance frequency to a high level.

6 is a diagram showing the relationship between the width W of the ground conductor removed portion of FIG. 3 and the resonance frequency.

7 is a diagram showing the relationship between the resonance frequency and the distance L from the open end of the ground conductor removed portion of FIGS. 3 and 5. FIG.

[Explanation of symbols]

 1 Dielectric board 2 Ground conductor 3, 4 Strip conductor 7, 8 Ground conductor removed part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuya Imaizumi 6-16-20 Ueno, Taito-ku, Tokyo Taiyo Induction Co., Ltd.

Claims (2)

[Claims] 1. A dielectric substrate, a ground conductor formed on one main surface of the dielectric substrate, and a strip conductor formed on the other main surface of the dielectric substrate. One end is open, and the other end of the strip conductor is connected to the ground conductor. When adjusting a resonance frequency of a stripline resonator, a part of the ground conductor facing the strip conductor is removed. And a method for adjusting a resonance frequency of a stripline resonator. 2. A dielectric substrate, a ground conductor formed on one main surface of the dielectric substrate, a strip conductor formed on the other main surface of the dielectric substrate, and one end of the strip conductor. A resonance frequency of a stripline resonator having a connection terminal coupled to a feeding point between the other end thereof, one end of the strip conductor being open, and the other end of the strip conductor being connected to the ground conductor. When adjusting the resonance frequency, a part of the ground conductor facing between the feeding point and the other end of the strip conductor is removed when it is desired to lower the resonance frequency, and when the resonance frequency is desired to be increased, the feeding point and the A method of adjusting a resonance frequency of a stripline resonator, comprising removing a part of the ground conductor facing the one end of the strip conductor.