JPH036102A - Frequency regulating structure - Google Patents

Abstract

PURPOSE:To miniaturize a device and to improve efficiency by providing first and second through-holes intersecting orthogonally to a rectangular parallelopiped dielectric, providing metallic films on five planes except for the plane where the first through-hole is provided and the inner plane of the through-hole, and eliminating the metallic film from the peripheral part of the aperture of the second through-hole. CONSTITUTION:Five first through-holes 31 are provided at a rectangular parallelopiped block consisting of a dielectric, and the second through-hole 33 extending from the arbitrary position of the through-hole 31 perpendicularly to one plane of the block is provided. The metallic films 34 are provided on the five planes except for either one plane B out of the planes where the first through-holes 31 are provided and the inner planes of the through-holes 31 and 33. The metallic film at the peripheral part of the aperture of the second through-hole 33 is eliminated. A coupling capacitor 41 having an input/output terminal 42 is connected to aperture parts at both ends of the aperture parts of five through-holes 31 at the side plane B, and the terminal 42 is connected to an input/output line. The through-hole 33 is provided at a position separated by 1/4 of the length of the through-hole from the through-hole 31, and an adjustable resonator is formed as a regulating stub.

Description

[Detailed Description of the Invention] [Summary] For example, regarding a frequency adjustment structure used in a dielectric filter for mobile radio equipment, it is possible to miniaturize the dielectric filter and surface-mount it on a printed circuit board, and to efficiently adjust the frequency in the mounted state. For the purpose of making the adjustment possible, at least two first
A through hole is provided, and a metal coating is applied to five surfaces excluding one of the surfaces where the first through hole opening is located and to the inner surface of the first through hole.

In a dielectric filter configured by attaching a single output portion to both end openings of at least two first through-hole openings on a surface without a metal coating, any of the first through-holes A second through hole is provided that penetrates upward from the position to one side of the rectangular parallelepiped block and has a metal coating on its inner surface, and the metal coating around the opening of the second through hole is removed.

[Industrial application field]

The present invention relates to a frequency adjustment structure used, for example, in a dielectric filter for mobile radio equipment.

In recent years, there has been a demand for miniaturization of mobile power line devices such as car telephones, so semi-coaxial dielectric filters using dielectrics with high dielectric constants have been used.

However, other components other than filters are efficiently and densely mounted on printed circuit boards, and dielectric filters can also be made smaller and mounted on printed boards, making it possible to efficiently adjust the frequency while mounted. It is necessary.

[Conventional technology]

FIG. 5 is a structural diagram of a conventional example, and FIG. 5(a) is a perspective view.

FIG. 5 (with) shows a sectional view taken along the line AA' in FIG. 5(a).

Hereinafter, the structure of a conventional example will be explained using a five-section dielectric filter as an example.

First, five through holes 11 are formed at predetermined intervals in a rectangular parallelepiped block 1 made of dielectric material as shown in FIGS. 5(a) and 5(b).
~15 will be provided. And the bottom surface B of this rectangular parallelepiped block
4 side surfaces and 5 surfaces of the top surface and through hole 1 except for
A metal coating (double lined part in the figure) is applied to all of the inner surfaces of 1 to 15, and input terminals 23 are applied to the through-hole openings 11' and 15'' at both ends of the through-hole openings on the bottom surface B. A coupling capacitor 22 and a coupling capacitor 24 with an output terminal 25 are soldered to form an input/output section.

Then, in order to ensure that the metal coating applied to the four sides is grounded, it is inserted into the metal case 21, and after soldering this metal case and the metal coating, all the legs 2 of the metal case are
11 and input/output terminals 23 and 25 are passed through holes provided in the printed board 26 and soldered to a ground plane and input/output lines formed on the back surface of the printed board (not shown).

In addition, since the length of the through holes 11 to 15 is λ/4, this part operates as a λ/4 resonator, and the electric field distribution is maximum on the upper surface O11 surface B, the former being the short-circuit surface and the latter being the short-circuit surface. becomes the open surface. Furthermore, since the coupling capacitor is provided on the open surface, the input and output sections are coupled at the maximum electric field.

[Problem to be solved by the invention]

Here, since the dielectric constant of the rectangular parallelepiped block varies, it is necessary to adjust the resonant frequency of the resonator, but this adjustment can be done by shortening the length of the resonator by scraping off the metal coating on the open surface of the resonator. 2 is being carried out.

However, as shown in FIG. 5(b), the open surface of the resonator (i.e.,
Since it is mounted with the lower surface B) facing down, it is extremely difficult to scrape off the metal coating on the open surface.

Furthermore, it is impossible to scrape off the metal coating on the open surfaces of the first and last stage resonators to which the input/output terminals 23 and 25 are connected.

For this reason, there is a problem in that the resonance frequency cannot be adjusted smoothly.

Furthermore, since the metal coating applied to the four sides is grounded to the printed board via the metal case, the dielectric filter is about one size larger than the rectangular parallelepiped block, and there is a problem that surface mounting is not possible. There is also.

SUMMARY OF THE INVENTION An object of the present invention is to miniaturize a dielectric filter so that it can be surface mounted on a printed board, and to enable efficient frequency adjustment in the mounted state.

[Means to solve problems]

FIG. 1 shows a block diagram of the principle of the present invention.

In the figure, 31 is a first through-hole (both of which are two) formed in a rectangular parallelepiped block made of a dielectric material, and 32 is a first through-hole provided in a rectangular parallelepiped block made of a dielectric material, and 32 is a first through-hole provided in a rectangular parallelepiped block made of a dielectric material. This is a metal coating applied to the five surfaces and the inner surface of the first through hole.

Further, 33 is a second through hole that penetrates upward from an arbitrary position of the first through hole to one side of the rectangular parallelepiped block and has a metal coating on its inner surface, and 35 is an opening of the second through hole. The surrounding area is shown.

[Effect]

In the present invention, the metal case is removed from the dielectric filter, and the filter is mounted horizontally on a printed board.

In such a mounting state, the first through hole 31 is parallel to the printed board, but if other components are mounted near the first through hole opening B, the resonator is opened as described above. It is difficult to scrape off the metal coating on the surface.

Therefore, as shown in FIG.
3 is provided, and a metal coating 34 is applied to the inner surface, and the metal coating around the opening portion 35 of the second through hole is removed, and the metal coating is applied to the inner surface of the second through hole and one surface of the rectangular parallelepiped block. Make sure that there is no contact with the coating.

In terms of an equivalent circuit, such a configuration can be considered to be a combination of the first resonant circuit 31 formed by the first through hole 33 and the second resonant circuit formed by the second through hole.
When the resonant frequency of the first resonant circuit is changed, the resonant frequency of the first resonant circuit is changed.

That is, the resonant frequency of the first resonator is adjusted by scraping off the metal coating applied to the inner surface of the second through hole 33 (hereinafter referred to as adjustment stub) and changing the length of the adjustment stub. be able to.

As a result, the electric filter can be further miniaturized and mounted on the surface of a printed board, and the frequency can be efficiently adjusted in the mounted state.

〔Example〕

FIG. 2 is a structural diagram (cross-sectional view) of an embodiment of the present invention.

3 is an explanatory diagram of the operation of FIG. 2, and FIG. 4 is an implementation diagram of FIG. 2. Here, the same reference numerals indicate the same objects throughout the figures. Below, FIGS. 2 to 4 will be explained.

First, as shown in FIG. 4, in a five-section dielectric filter using the present invention, five first through holes 31 are provided in a rectangular parallelepiped block 3 made of a dielectric material, and five first through holes 31 are provided in a rectangular parallelepiped block 3 made of a dielectric material. A metal coating is applied to the inner surface of the first through hole. A coupling capacitor 41 with input terminals 42 attached to openings at both ends of the five first through-hole openings on the side surface B. A coupling capacitor 43 with an output terminal 44 is connected.

Further, from each first through-hole opening part, for example, the first
A second through hole 33 is provided toward the top surface of the rectangular parallelepiped block from 1/4 of the through hole length (λ/4), and
A metal coating is applied to the inner surface of this hole. Although the metal coating around the second through-hole opening 35 is removed, this second through-hole is used as an adjustment stub.

That is, by soldering and connecting the bottom surface of the rectangular parallelepiped block to the ground plane (not shown) on the top surface of the printed board 26, and the input/output terminals 42 and 43 to the input/output lines (not shown), The metal case used is removed and surface mounted on the printed circuit board, and the frequency adjustment is performed by removing the metal coating on the inner surface of the second through hole opening, so the input/output coupling part is removed. The attached first and final stage resonators can also be adjusted.

Next, the operation of the frequency adjustment structure shown in FIG. 2 will be explained with reference to FIG.
D" sectional view, Figure 2(b) is a cc' sectional view, and the difference between Figure 2(a) and Figure 2(b) is whether there is an input terminal 42 and a coupling capacitor 41. This is the difference.

Now, as shown in FIG. 2, a first through hole with a length of λ/4, that is, a first resonator 31 is provided in a rectangular parallelepiped block 3 made of a dielectric material, and a first through hole with a length of λ/4, that is, a first resonator 31 is provided. λ/4) are provided with second through holes, that is, adjustment stubs 33, and the inner surfaces of these through holes are coated with the metal coating 3 on the birch.
2.34 has been applied.

Then, apply the metal coating on the inner surface of the adjustment stub to Δ! By shaving off only .DELTA.f, the resonant frequency of the first resonator changes by .DELTA.f, as shown in FIG.

Here, ■ in FIG. 3 is the diameter d of the first resonator when the metal coating on the open surface is scraped off as in the conventional case.

When the diameter dt of the adjustment stub is the same as that of the adjustment stub, and the metal coating of this stub is to be scraped off, ■ indicates the case where d>d o and the metal coating of the adjustment stub is scraped off.

In other words, in the case of 9 the present invention, as shown in ■, the adjustment stub is tilted more than ■ in order to scrape off the metal coating of the adjustment stub at a position (L/4) (λ/4) away from the open surface where the electric field is maximum. However, even at the same position, as d becomes smaller than d, the slope increases as shown in ■, and Δf becomes smaller for the same Δl.

Although not shown in Figure 3, there are dl and d near the open surface.
If adjustment stub 2 is provided, the slope approaches 2, and rough frequency adjustment can be performed.

However, if a stub for adjustment of d, > d2 is provided near the short-circuit surface on the opposite side, the slope will be higher than ■, and fine adjustment will be possible. Since the stub allows adjustment of the resonant frequency, frequency adjustment is performed smoothly.

As described above, in the present invention, the dielectric filter can be made smaller and mounted on the surface of a printed circuit board, and the frequency can be adjusted efficiently in the mounted state.

Fig. 2 is a structural diagram (cross-sectional view) of the embodiment of the present invention, Fig. 3 is an explanatory diagram of the operation of Fig. 2, Fig. 4 is an implementation diagram of Fig. 2, and Fig. 5 is a structural diagram of the conventional example. show.

In the figure, 3 is a rectangular block, 31 is a first through hole; 32 and 34 are metal coatings, 33 is a second through hole; Reference numeral 35 indicates a portion surrounding the opening of the second through hole.

〔Effect of the invention〕

As explained in detail above, according to the present invention, one dielectric filter can be made smaller and mounted on a printed board, and the frequency can be adjusted efficiently in the mounted state.

[Brief explanation of drawings]

Figure 1 is a block diagram of the principle of the present invention. Heather? Bright Principle 7077 Diagram 1st mouth ′! Figure 53 secondly 2 Otsu Figure 2 implementation diagram Figure 4

Claims (1)

[Claims] A rectangular parallelepiped block (3) made of a dielectric material has at least two
A first through hole (31) is provided, and five surfaces excluding one surface (B) of the surfaces where the first through hole opening is located and an inner surface of the first through hole. A metal coating (32) is applied to the metal coating (32), and an input/output part is attached to the openings at both ends of at least two first through-hole openings on the surface (B) on which no metal coating is applied. In the dielectric filter, a second through hole (33) is provided upwardly from an arbitrary position of the first through hole to one surface of the rectangular parallelepiped block and has a metal coating (34) on the inner surface, A frequency adjustment structure characterized in that a metal coating around a second through-hole opening (35) is removed.