JPS6042507Y2 - high frequency filter - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a high-frequency filter used in equipment that handles high-frequency signals, such as line amplifiers and mixers for common television reception, and television receivers.

The purpose of this invention is to provide a high frequency filter having a structure that can be extremely miniaturized.

The drawings showing the embodiments of the present application will be described below.

In FIGS. 1 to 4 showing a bandpass filter as an example of a high frequency filter, numeral 1 indicates a substrate, which is constructed using a well-known insulating plate.

Reference numeral 2 indicates a conductive thin plate, which is constructed using a thin copper plate and is attached to one surface of the substrate 1.

A portion 3 of the conductive thin plate 2 is removed by etching means to form an input terminal 4, an output terminal 5, a circuit pattern 6, a ground circuit 7, etc. in a well-known manner.

The substrate 1 and the conductive thin plate 2 described above are generally known as printed circuit boards.

Next, the filter element 8 constructed between the input terminal 4 and the output terminal 5 will be explained.

9 and 10 each indicate a parallel resonant circuit, and each coil "U"
It is constructed by connecting L2 and capacitors C2 and C4 in parallel.

C□, C3, and C5 indicate coupling capacitors.

The above coil and capacitor are formed on the conductive thin plate 2, including an input terminal 4, an output terminal 5, a circuit pattern, and a ground circuit 7.
etc. are mechanically and electrically connected to each other by soldering means to form a circuit as shown in FIG.

Further, as shown in FIGS. 2 to 4, the coils h and L2 are provided with one of them on one side of the substrate and the other on the other side of the substrate, and the central axes of these coils are 11. 12 are arranged so as to cross each other.

The intersecting states include orthogonal and oblique.

These coils generally have a diameter of a diameter and a length of a number to an even number.

With the above configuration, when various signals over a wide frequency range enter the input terminal 4, only those signals that match the passband of the filter element 8 are sent to the filter element 8 as is well known. and appears at output terminal 5.

In this case, both the coils L, , L are shielded from high frequencies by the conductive thin plate 2, and their axes 11
．． Since the filters 12 are in a crossed shape and there is no mutual electromagnetic inductive coupling, the electrical characteristics as a filter are good (pass band is small).

The input terminal 4 and the output terminal 5 may be constructed with independent terminals as shown in FIGS. 2 to 4, or may be constructed with a single-wire connected to the capacitor C1 or C6.

Next, FIG. 5 shows a circuit of a band rejection filter as another example of a high frequency filter, in which the filter element 8
E is constructed by combining a parallel resonant circuit 21 consisting of coils L, 11 and a capacitor C1□, and a series resonant circuit 22 consisting of a coil L□2 and a capacitor C1°.

Next, FIG. 6 shows a specific example of the structure of the filter shown in FIG.
A rectangle with the minimum length that can accommodate (rectangle with the minimum dimensions)
It is on formation.

Next, FIGS. 7 and 8 show examples in which the positional relationship between coil L and coil L1° is different from each other in the filter having the configuration shown in FIG. 6. Even if the relationships shown in the figures are made, it is sufficient to use the minimum size of the substrate 1e.

Further, in these examples, both coils are placed so as to intersect with each other at right angles, but these two coils may be placed in an oblique manner.

Note that these figures are functionally the same as those in the previous embodiment.
Alternatively, for parts that are considered to have an equivalent configuration, the same reference numerals as in the previous version are appended with the letter e, and redundant explanations are omitted.

(Furthermore, in the next and subsequent articles, the same idea will be followed, and the alphabets f and g will be added in order, and redundant explanation will be omitted.

) Next, FIGS. 9 and 10 respectively show different examples of high frequency filters.

In FIG. 9, capacitors C21 to C23 and coil L21. A high-pass filter is constructed using L22, and in FIG. 10, a low-pass filter is constructed using coils L3□, L32 and capacitor C31.

As mentioned above, in this invention, (1) two coils 1 constituting the filter element 8,
One of the coils L2 is placed on one side of the board 1, the other on the other side, and both coils L1? Since the coils LL, 1 and 2 are attached to each other in a state where a part of L2 is polymerized, the coils LL, 1, 2
It is possible to reduce the size of the substrate 1 in the planar direction on which the filter is mounted, which has the effect of making it possible to reduce the size of the filter by reducing the size of the substrate.

(2) Since the substrate 1 is a substrate with a conductive thin plate 2 attached, the conductive thin plate 2 is attached to both the coils Ll and L.
2 are shielded from each other at high frequency, and for this reason, both of the above coils L□
9 "2 can be placed close to the substrate 1, and the dimension H in the height direction (direction perpendicular to the substrate) can also be reduced. In addition to the miniaturization of the filter according to (1) above, it is possible to further reduce the size of the filter. This has the effect of enabling miniaturization.

(3) Furthermore, since the above-mentioned two coils Ll and L2 are in a positional relationship in which their respective central axes intersect with each other, both coils L1. It has the advantage of being able to prevent electromagnetic coupling of L2 as much as possible.

This makes it possible to reduce the size of the substrate 1 while maintaining the shielding effect described in (2) above, and has the effect of further reducing the size of the filter.

[Brief explanation of drawings]

The drawings show an embodiment of the present application. Fig. 1 is a circuit diagram of a band-pass filter, Fig. 2 is a perspective view showing the front side of the filter, Fig. 3 is a perspective view showing the back side of the filter, and Fig. 3 is a perspective view showing the back side of the filter. Figure 4 is a side view, Figure 5 is a circuit diagram of the band rejection filter,
Fig. 6 is a plan view of the same, Figs. 7 and 8 are plan views for explaining the positional relationship of the two coils (the board is shown with imaginary lines), and Fig. 9 is a circuit diagram of the high-pass filter. , FIG. 10 is a circuit diagram of a low-pass filter. 1... Substrate, 2... Conductive thin plate, 4...
...Input terminal, 5...Output terminal, 8...
...filter element, '1? L2... Coil, 11, 12... Center axis line.

Claims (1)

[Scope of utility model registration request] In a high frequency filter that includes a filter element consisting of two coils between an input terminal and an output terminal, one of the two coils is attached to one side of the substrate to which a conductive thin plate is attached, and the other is attached to the substrate. The two coils are attached to the other surface, and the positional relationship between the two coils is such that when viewed from a direction perpendicular to the substrate, both coils partially overlap and the central axes of the respective coils intersect with each other. A high frequency filter that is characterized by: