JPS6320046B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to circuit components, and particularly to circuit components used in a high frequency region, and is aimed at improving the characteristics thereof.

Circuit components have become smaller and smaller in recent years, and can now be used in high frequency ranges. However, in a circuit component having three or more terminals and having an input terminal and an output terminal, there is a problem of miniaturization of the circuit component and direct coupling between the input terminal and the output terminal. For example, as a circuit component,
To explain in the case of a surface acoustic wave filter as shown in the figure, a filter element 1 using surface acoustic waves as a circuit element is fixed to a printed wiring board 2 which is also a substrate holding the circuit element, and a printed wiring 3, For example, they are electrically connected by wire bonding. Terminals 4, 5, and 6 for connection to an external circuit are attached to the printed wiring 3. Here, the bonding wires, printed wiring, and terminals constitute input signal connection means for supplying electrical signals to the circuit element and output signal connection means for supplying electrical signals from the circuit element to an external circuit. When an electrical signal is applied from the input terminal 4, it is waved by the filter element 1, and an output signal with a predetermined frequency characteristic is obtained at the output terminal 5. However, if left as is, the characteristics of the filter element 1 are often not fully exhibited, resulting in failure to obtain a sufficient guaranteed attenuation amount or insufficient trap attenuation amount.
Conventionally, this is thought to be due to electrostatic coupling between the input and output, and a ground terminal 6 is provided between the input terminal 4 and the output terminal 5, or a ground electrode is provided in the filter element 1. 7 has been placed. In normal cases, almost the desired characteristics can be obtained with this level of countermeasures, but in cases where guaranteed attenuation and trap attenuation are strictly required, even if the electrostatic shielding by grounding is strict, the circuit components cannot be used. There were limits to its characteristics, which posed a problem.

FIG. 2 is a schematic diagram for explaining electromagnetic induction coupling of the surface acoustic wave filter of FIG. 1. FIG. That is, the current path of the input signal flowing through the input terminal 4, printed wiring 3, and filter element 1 in FIG. 1 can be considered as the loop 21 in FIG.
Similarly, the current path of the output signal on the output side can be considered in the loop 22. Here, a high frequency current is applied to the input terminal. When a current flows in the direction of the arrow 23, a magnetic flux is generated in the loop 21 in the direction 24 toward the front from the plane of the paper. This magnetic flux is
Outside the loop 21, direction 2 from the front toward the page
5, an electromotive force 26 is generated at the terminal in the loop 22 on the output side. The closer these loops are, the greater the electromotive force becomes. FIG. 3 shows the results of actually measuring the degree of coupling when changing the length of these loops. The number of terminals on the horizontal axis corresponds to the number of terminals of the entire circuit component in the model of FIG. 1, and two terminals from both sides serve as input terminals and output terminals. When the number of terminals is three, it is assumed that one of the input and output terminals is common. The attenuation was measured using a 50 ohm system at a frequency of 60 MHz. The conductors forming the loop were 0.5 mm wide and arranged in parallel at 2.54 mm intervals, and the length of both the input and output loops was 600 mm. From the results in Figure 3, the fewer the number of terminals, the more
In other words, the closer the distance between the loops, the greater the coupling. In conventional circuit components, the coupling between input terminals and output terminals due to electromagnetic induction as described above was ignored, but with the expansion of the application of circuit components to high frequency ranges and the demand for smaller shapes, this is becoming more and more important. This has become an issue that cannot be ignored.

The circuit component according to the present invention provides a three-dimensional intersecting portion in at least one of the current paths of the input and output ends, and cancels the electromagnetic inductive coupling from the other current path, thereby achieving the above-mentioned effect. This solves the problem.

Below, examples thereof will be given and explained in detail.

FIG. 4 shows the configuration of an embodiment in which the present invention is applied to a surface acoustic wave filter as a circuit component. A filter element 41, which is a circuit element, is fixed to a printed wiring board 42, which is also a substrate for holding the circuit element, and is electrically connected to printed wiring 44 by wire bonding 43. Here, part of one side of the input/output printed wiring (in the diagram, it is the output side),
so that the polarity of the electromagnetic inductive coupling is reversed with the other,
A through hole 50 is provided, and wiring is provided on the back side of the printing room board 42, so that the outgoing path and the incoming path of the current path intersect three-dimensionally. Printed wiring 44 of the printed wiring board 42
Input terminal 46, output terminal 47 and ground terminal 4 are connected to
Connect 8. These terminals 46, 47, 48
is connected to another printed wiring board 49 equipped with an external circuit. To cancel the electromagnetic inductive coupling between the input current path and the output current path, the magnetic flux generated by the input current path must be transferred to the output terminal 47.
The component passing through the area from the connection point of the other printed wiring board 49 to the point where the printed wiring intersects three-dimensionally is made equal to the component passing through the area on the circuit element side from the point three-dimensionally intersecting. , the electromagnetic inductive coupling from the input side to the output side is canceled out and removed.

As mentioned above, this can also eliminate electromagnetic inductive coupling at the input terminal 46 and output terminal 47, so the length of the input terminal 46 and output terminal 47 to the connection point with other printed wiring boards can be reduced. It is better to keep it constant. In order to regulate the length up to the printed wiring board 49 to be constant, it is effective to provide a convex portion 45 on the terminal.

FIG. 5 shows another embodiment, which eliminates the need to use both sides of the printed wiring board. This has a structure in which the printed wiring 52 passes under the surface acoustic wave filter element 51. If you create the structure shown in the figure and place the region where the phase of electromagnetic induction coupling is reversed close to the other loop, the coupling will be strong, so the region where the phase is reversed will only need to be small.

Although the embodiments shown in FIGS. 4 and 5 are effective when the number of terminals is four or more, the present invention can also be applied to a three-terminal type piezoelectric filter.

6 and 7 are diagrams each showing an embodiment in which the present invention is applied to a three-terminal piezoelectric filter. Each of the piezoelectric filter elements 61 and 71 is
A split electrode is arranged on one side (here, the top surface) and a common electrode is placed on the other side, and when an input signal is applied between one of the split electrodes and the common electrode, the other side of the split electrode and the common electrode are arranged. An output signal is obtained between Here, as in the above embodiment, in order to provide a part of the printed wiring on the input side or a part of the printed wiring on the output side with a part where the polarity of the electromagnetic inductive coupling is reversed, as shown in FIG. Alternatively, an inverted area may be provided in the printed wiring 63 connected to the input terminal or the output terminal 62, or an inverted area may be provided in the printed wiring 72 connected to the common electrode, as shown in FIG.

As described above, the present invention cancels out electromagnetic induction on the input side and the output side. In conventional 60MHz band surface acoustic wave filters that only have electrostatic shielding, the first
With the configuration shown in the figure, there is an electromagnetic induction of about -50 decibels,
It was not possible to obtain the original characteristics of the filter element. In contrast, in the configurations of the embodiments shown in FIGS. 4 and 5, the electromagnetic induction could be canceled out and reduced to about -80 decibels. As a result, it was possible to obtain an effective trap characteristic of the filter.

In the embodiments shown in FIGS. 4 and 5, the electrode arrangement within the filter element is also part of the loop, so if there are variations in the installation position of the element during mass production, it will change to a loop shape. Fluctuations in the strength of electromagnetic inductive coupling were observed.

Above, in order to facilitate understanding of the present invention, a filter element, and more specifically, a filter element using a piezoelectric material, has been described. However, it is clear from the above description that the present invention is applicable not only to filters, but also to delay lines, other semiconductor circuit components, and circuit components formed by combinations thereof. be. Although only a configuration example using printed wiring has been described, it is also possible to implement the lead terminal in a loop shape, or to implement it using a beam lead or a film carrier.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of the configuration of a conventional surface acoustic wave filter, Figure 2 is a diagram to explain the electromagnetic induction coupling of the surface acoustic wave filter in Figure 1, and Figure 3 is a diagram showing the electromagnetic induction effect. Figures 4, 5, and 6 are diagrams illustrating an embodiment of the circuit component according to the present invention.
FIG. 7 and FIG. 7 are diagrams showing other embodiments, respectively. 41... Surface acoustic wave filter element, 42... Printed wiring board, 44... Printed wiring, 46... Input terminal, 47... Output terminal, 48... Ground terminal, 51
... Surface acoustic wave filter element, 52 ... Printed wiring, 61 ... Piezoelectric filter element, 63 ... Printed wiring, 71 ... Piezoelectric filter element, 72 ... Printed wiring, 81 ... Surface acoustic wave filter element, 82 ……
Printed wiring board, 83...electrode, 84...printed wiring.

Claims (1)

[Scope of Claims] 1. A circuit element that is active or passive or a combination thereof; input signal connection means for supplying an electrical signal to the circuit element from an external circuit;
an output signal connection means for supplying an electrical signal from the circuit element to an external circuit; a current path for an input signal flowing through the circuit element and the input signal connection means; and a current path between the circuit element and the output signal connection means. In the configuration with the current path of the output signal flowing through the
By holding the circuit element on a substrate and forming at least one of the current paths three-dimensionally intersecting each other using both surfaces of the substrate, a current path for the input signal and a current path for the output signal are formed. A circuit component characterized in that the electromagnetic inductive couplings of are arranged so that the strengths are substantially equal and the phases are of opposite polarity with the above-mentioned intersection as a boundary. 2. A circuit element that is active or passive or a combination thereof, and an input signal connection means for supplying an electrical signal to the circuit element from an external circuit;
an output signal connection means for supplying an electrical signal from the circuit element to an external circuit; a current path for an input signal flowing through the circuit element and the input signal connection means; and a current path between the circuit element and the output signal connection means. In the configuration with the current path of the output signal flowing through the
By holding the circuit element on a substrate and arranging any of the connection means at the interface between the substrate and the circuit element, the current path on the surface of the circuit element and the current path of any of the connection means are three-dimensionally connected. By forming the current path of the input signal and the current path of the output signal to intersect with each other, the electromagnetic inductive coupling between the current path of the input signal and the current path of the output signal is arranged such that the strength is approximately equal and the phase is of opposite polarity with the crossing portion as a boundary. A circuit component characterized by: