JPS62233911A - Low-pass filter - Google Patents

Abstract

PURPOSE:To obtain a low-pass filter with sharp cut-off frequency and a comparatively low frequency by setting both terminals of one electrode of spiral electrode opposed to each other via a dielectric to a transmission signal pass terminal and connecting one side terminal of the other spiral electrode to ground. CONSTITUTION:The spiral electrodes 12, 13 are opposed to each other via a dielectric, an optional one spiral electrode e.g., 12 is connected to a signal pass line and an optional terminal of the other spiral electrode 13 is connected to ground. Thus, a potential difference is generated effectively between parallel two wires to form a distribution capacitor and the low-pass filter whose cut-off frequency characteristic is sharp is realized without reducing the Q of the spiral electrode being the signal path line.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a low-pass filter for noise suppression used in signal passing circuits, power supply circuits, etc. in electronic equipment.

2. Description of the Related Art In recent years, low-pass filters have come into widespread use as noise cut filters in digital electronic equipment such as computers.

An example of a conventional low-pass filter will be described below with reference to the drawings.

FIGS. 3 and 4 show a configuration diagram and an equivalent circuit of a conventional low-pass filter. In FIG. 3, 1 is a signal passing line, 2 and 3 are signal passing terminals, and 4 is a ground electrode. FIG. 4 is an equivalent circuit of the low-pass filter shown in FIG. 3. In FIG. 4, 5 is a signal passing line, 6 and 7 are signal passing terminals, a distributed capacitor 8 is formed between the signal passing line 5 and the ground electrode 9, and the capacitance of this distributed capacitor 8 and the signal passing line 5 are The inductance constituted a low-pass filter.

Problems to be Solved by the Invention However, in the above configuration, since the ground electrode 4 is installed close to all parts of the signal passing line 5, the Q of the inductance in the signal passing line 1 is significantly reduced. However, there was a problem in that a low-pass filter with sharp cutoff frequency characteristics could not be realized.

In view of the above-mentioned problems, the present invention provides a low-pass filter that has sharp cutoff frequency characteristics, is ultra-thin, and has a relatively low frequency band despite its small size.

Means for Solving the Problems In order to solve the above problems, the low-pass filter of the present invention sets both terminals of an arbitrary one side of the spiral electrodes as transmission signal passing terminals in the spiral electrodes that are installed facing each other with a dielectric interposed therebetween. However, any terminal on one side of the other spiral electrode is set to ground.

Effect of the present invention With the above-described configuration, a distributed capacitor is formed by effectively generating a potential difference between two parallel wires, and the cutoff frequency is reduced without lowering the Q of the spiral electrode that is a signal passing line. A low-pass filter with sharp characteristics will be realized.

Embodiment Hereinafter, a low-pass filter according to an embodiment of the present invention will be described with reference to the drawings.

FIGS. 1(a) to (C) show configuration diagrams of a low-pass filter according to a first embodiment of the present invention, (al is a front view, (b) is a side view, and (C) is a back view. Figure 1.
In the figure, 11 is a dielectric, 12 is a signal passing line spiral electrode, 13 is an earth line spiral electrode, and 14 and 15 are signal passing terminals.

The operation of the low-pass filter configured as described above will be explained below using FIG. 2.

FIG. 2 shows an equivalent circuit, in which 16 is a signal passing line, 17 and 18 are signal passing terminals, 19 is a ground line, and 20 is a parasitic distributed capacitor.

As described above, according to this embodiment, there is no reduction in the Q of the signal passing line spiral electrode, and as a result, an ultra-thin low-pass filter with a sharp cutoff can be easily constructed using the printing method. .

In addition, the dielectric material is alumina ceramic, 4 tabari,
Plastic, Teflon, glass, Maya, resin-based printed circuit boards, etc. can be used.

Further, the shape of the dielectric body is not limited to a plate shape, but may be a cylindrical shape or a rectangular tube shape, and electrodes may be provided on the outer and inner peripheries of the dielectric.

Effects of the Invention As described above, in the present invention, spiral electrodes are disposed opposite to each other via a dielectric, any one of the spiral electrodes is set as a signal passing line, and one end of the other spiral electrode is set to ground. As a result, it is possible to easily construct a low-pass filter that is ultra-thin and small but has a sharp cutoff and relatively low-pass.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a low-pass filter according to an embodiment of the present invention, Fig. 2 is an equivalent circuit diagram of Fig. 1, Fig. 3 is a block diagram of a conventional low-pass filter, and Fig. 4 is a block diagram of a conventional low-pass filter. It is an equivalent circuit diagram. 11...Dielectric material, 12.16...Signal passing line spiral electrode, 13.19...Earth line spiral electrode, 14, 15...Signal passing Terminal, 20... Distributed capacitor. Agent's name Patent attorney Toshio Nakao One idiot Figure 1 A Blind sign road difference Kyouko Signal line blockage Myco q Earth drunken error j Sunoshiral i Une

Claims (1)

[Claims] A low-pass filter characterized in that both terminals of an arbitrary one side of spiral electrodes that are placed opposite each other via a dielectric are set as transmission signal passing terminals, and an arbitrary one side terminal of the other spiral electrode is grounded.