JP2003133805A - Band pass filter, and high frequency device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a band pass filter which is low in insertion loss while securing the quantity of attenuation of desired frequency largely. SOLUTION: A pattern inductor 15a and a pattern inductor 15b are roughly square-shaped, and this band pass filter has a coupling 20 having one side of each of the pattern inductors 15a and 15b facing each other. Each side adjoining this coupling and corresponding to each other is provided with capacitors 16a and 16b for resonance. This band pass filter is provided with an in/out terminal 18a via a capacitor 17a for coupling from the vicinity of the capacitor 16a for resonance, and also this is provided with an in/out terminal 18b via a capacitor 17b for coupling from the vicinity of the capacitor 16b for resonance. This filter is provided with a coupling degree adjusting means 35 made of a pattern in a position eccentric from the center 21 of the coupling 20. Hereby, a band pass filter low in insertion loss can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bandpass filter formed of a ring resonator and a high frequency device using the bandpass filter.

[0002]

2. Description of the Related Art A conventional bandpass filter will be described below. As shown in FIG. 18, a conventional bandpass filter includes a pattern inductor 1a and a resonance capacitor 2a connected in parallel with the pattern inductor 1a.
And the pattern inductor 1a to the coupling capacitor 3
A ring resonator 5a composed of an input / output terminal 4a connected via a, a pattern inductor 1b, and a resonance capacitor 2 connected in parallel with the pattern inductor 1b.
b and the pattern inductor 1b to the coupling capacitor 3
A ring resonator 5b composed of an input / output terminal 4b connected via b, and these ring resonator 5a and ring resonator 5b were provided on a substrate to form a bandpass filter.

The ring resonator 5a and the ring resonator 5b have a circular shape, and each of the ring resonators 5a and 5b has a circular shape.
a and 5b are symmetrically arranged to face each other to form the coupling portion 6, and the coupling degree is adjusted by the adjustment capacitor 9 to adjust the attenuation poles (see FIG. 19) 7 and 8.

As described above, in the conventional bandpass filter, the ring resonator 5a and the ring resonator 5b have a circular shape, and the ring resonators 5a and 5b are arranged symmetrically opposite to each other. That is, as shown in FIG. 19, the pass characteristic has a center frequency (center frequency of the pass band) 10
On the other hand, the attenuation poles 7 and 8 were symmetrical. Therefore, when one attenuation pole 7 is moved toward the center frequency 10 by 11, for example, the other attenuation pole 8 also moves toward the center frequency 10 by 11. Therefore, for example, when one attenuation pole 7 approaches the center frequency 10, the other attenuation pole 8 also approaches the same amount by the same amount, so that the insertion loss 13 of the pass characteristic at the center frequency 10 is increased due to the influence of the attenuation pole 12. It was.

Here, the horizontal axis represents frequency (MHz) and the vertical axis represents pass characteristic (dB). As a technique related to this, there is, for example, Japanese Patent Publication No. 8-2001.

[0006]

However, in actual use, the characteristics of both the attenuation pole 7 and the attenuation pole 8 are not always used, and in many cases only one of them is used. At that time, there was a demand to reduce the insertion loss at the center frequency 10.

In order to solve this problem, the present invention has an object to provide a bandpass filter having a small insertion loss while ensuring a large amount of attenuation at a desired frequency, and a high frequency device using the bandpass filter. It is a thing.

[0008]

In order to achieve this object, a pattern inductor of a bandpass filter according to the present invention is such that the first pattern inductor and the second pattern inductor are substantially quadrangular and each pattern inductor is A first resonance capacitor and a second resonance capacitor are provided on the respective sides adjacent to and corresponding to the coupling portion, and in the vicinity of the first resonance capacitor. To a first input / output terminal via a first coupling capacitor, and a second input / output terminal from near the second resonance capacitor via a second coupling capacitor. The coupling degree adjusting means formed in a pattern is provided at a position eccentric from the center of the.

As a result, it is possible to obtain a bandpass filter with a small pass loss while securing a large amount of attenuation at a desired frequency.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention includes a first pattern inductor, a first resonance capacitor connected in parallel with the first pattern inductor, and the first pattern. A first ring resonator composed of a first input / output terminal connected from the inductor through a first coupling capacitor, a second pattern inductor, and a second pattern inductor connected in parallel. A second resonance capacitor and a second connection from the second pattern inductor via a second coupling capacitor.
And a second ring resonator including an input / output terminal of the first ring resonator and the second ring resonator provided on a substrate. The pattern inductor and the second pattern inductor have a substantially quadrangular shape, and each have a coupling portion opposed to one side of each pattern inductor, and the first side is provided on each side adjacent to and corresponding to the coupling portion. The resonance capacitor and the second resonance capacitor are provided, the first input / output terminal is provided from near the first resonance capacitor through the first coupling capacitor, and the second resonance capacitor is provided. The second input / output terminal is provided from the vicinity of the resonance capacitor via the second coupling capacitor, and the coupling degree is formed in a pattern at a position eccentric from the center of the coupling portion. It is a bandpass filter provided with the adjusting means, and has a coupling portion that couples on the opposite sides of the substantially rectangular pattern inductance, and since a resonance capacitor is provided on the side adjacent to one side of this coupling portion, The mounting position of this resonance capacitor becomes asymmetric.
That is, since the coupling between the resonators in the phase opposite to the phase excited in the resonator or in the same phase becomes strong, the positions of the attenuation poles generated above and below the center frequency of the bandpass filter are asymmetrical. Become. Therefore, the insertion loss at the center frequency when one of the attenuation poles is brought close to the center frequency can be reduced as compared with the conventional symmetrical case. That is, it is possible to obtain a bandpass filter with a small insertion loss.

Further, since it has a coupling degree adjusting means,
The position of the attenuation pole can be adjusted to obtain the optimum amount of attenuation.

According to a second aspect of the present invention, there is provided the bandpass filter according to the first aspect, wherein the coupling degree adjusting means is linearly provided in a pattern on the centerline of the coupling portion and has one end connected to the ground. By creating this pattern, one of the asymmetrical attenuation poles can be greatly separated from the center frequency. Therefore, the contribution of this distant attenuation pole to the center frequency is reduced, so that the insertion loss is improved.

The coupling degree adjusting means of the invention according to claim 3 is the bandpass filter according to claim 1, wherein convex portions projecting from the respective pattern inductors toward the counterpart pattern inductors are formed. By cutting this pattern, the frequency of the attenuation pole can be adjusted in the direction away from the center frequency. Further, since it is formed in a pattern, it does not lead to an increase in cost.

The invention according to claim 4 is the band-pass filter according to claim 2, which has a convex portion protruding from each pattern inductor toward the corresponding pattern inductor, and is formed in a linear shape. While keeping one attenuation pole away from the center frequency on both the pattern and the convex portion,
Since one of the required attenuation poles can be adjusted to a frequency that requires a high attenuation amount, it is possible to achieve a high attenuation amount at a desired frequency while suppressing the insertion loss at the center frequency. Also, the adjustment range of the attenuation pole can be increased.

The invention described in claim 5 is at least the first aspect.
2. The bandpass filter according to claim 1, wherein the resonance capacitor and the second resonance capacitor use chip parts, and these chip parts are reflow-soldered with cream solder. As a result, the mounting position of the chip component becomes constant due to the self-alignment effect. This means that the inductance on the positive phase side and the negative phase side of the pattern inductor becomes constant, so that the pass characteristic of the bandpass filter becomes stable.

According to a sixth aspect of the present invention, the input / output terminal is the bandpass filter according to the first aspect, which is provided on the side opposite to the coupling portion with respect to the resonance capacitor, and has an attenuation pole on the low frequency side. It can be made closer to the center frequency than the attenuation pole on the high frequency side.

The input / output terminal of the invention according to claim 7 is provided on the coupling portion side with respect to the resonance capacitor.
In the bandpass filter described in (1), the attenuation pole on the high frequency side can be made closer to the center frequency than the attenuation pole on the low frequency side.

The invention according to claim 8 is the bandpass filter according to claim 1, wherein at least one of the first resonance capacitor and the second resonance capacitor is a variable capacitor. Yes, the center frequency can be changed. Further, by finely adjusting each independently, it is possible to adjust the pass characteristic in accordance with the dimensional variation of the first pattern inductor and the second pattern inductor.

According to a ninth aspect of the present invention, varicap diodes are used for the first resonance capacitor and the second resonance capacitor, and a voltage is applied to each varicap diode from one control voltage supply terminal. The bandpass filter according to claim 1, which supplies the varicap capacitor, so that the position of the center frequency can be electrically controlled. Further, since the control voltage can be supplied from one control voltage supply terminal, control becomes easy.

The invention according to claim 10 is the bandpass filter according to claim 9, wherein a varicap diode is used for the first coupling capacitor and the second coupling capacitor, and the center frequency is changed. The passband width which changes when the voltage is caused can be corrected by using this coupling varicap diode.

The substrate according to the eleventh aspect of the present invention is the bandpass filter according to the first aspect using an alumina substrate or a Teflon substrate. Since the dielectric loss is small, the pass loss can be suppressed small and the attenuation pole The amount of attenuation at can also be made large.

The twelfth aspect of the invention is the bandpass filter according to the first aspect, wherein the bandpass filter has a module shape and is surface mountable. Since the bandpass filter has a module shape, management and automatic mounting are possible. It's easy. Further, since surface mounting is possible, reflow soldering can be performed.

The module of the invention described in claim 13 is
The bandpass filter according to claim 12, which is covered with a metal shield case, can suppress the radiation loss, have a small passing loss, and can have a large amount of attenuation at the attenuation pole. In addition, unnecessary radiation waves are not emitted to the outside and electromagnetic interference from the outside is not received.

According to a fourteenth aspect of the present invention, the shield case is cut by a mold, bent in the cutting direction, and brought into contact with an electrode formed on a side surface of the substrate.
In the bandpass filter according to 3, the burr generated at the time of cutting abuts on the electrode, and a gap is generated between the electrode and the bent portion of the shield case. Therefore, the solder is filled in the voids by a capillary phenomenon, so that reliable soldering can be performed.

According to a fifteenth aspect of the present invention, an input terminal and
The signal input to this input terminal is supplied to one input and the other input is supplied with a first mixer to which the output of the first local oscillator is connected, and the output of this first mixer. And a second mixer having an output of the bandpass filter supplied to one input and an output of a second local oscillator connected to the other input. , A high frequency device having an output terminal to which the output of the second mixer is supplied, and since the filter of the present invention is used as the intermediate frequency filter of the double super receiver, the image interference frequency is reliably removed. It is possible to reduce the loss in the pass band (intermediate frequency).

According to a sixteenth aspect of the present invention, an input terminal and
An input filter to which the signal input to this input terminal is supplied, a mixer in which the output of this input filter is supplied to one input and the output of the local oscillator is connected to the other input, and this mixer Is a high-frequency device having the bandpass filter according to claim 1 to which the output of the bandpass filter is supplied, and an output terminal to which the output of the bandpass filter is supplied, the filter of the present invention being an intermediate frequency filter of a single super receiver. Since it is used, the adjacent interfering signal can be reliably removed, and the loss in the pass band (intermediate frequency) can be reduced.

According to a seventeenth aspect of the present invention, an input terminal and
The bandpass filter according to claim 9 connected to this input terminal, and a mixer in which the output of this bandpass filter is supplied to one input and the output of a local oscillator is connected to the other input. It is a high-frequency device having an output terminal to which the output of this mixer is supplied, and since it is possible to electrically control the center frequency, it can be used as an input filter of a single super-reception device, and image interference is surely performed. The frequency can be removed, and the loss in the pass band can be reduced.

The invention as set forth in claim 18 is a frame made of metal, a printed circuit board mounted in the frame via a mounting portion, and a bandpass according to claim 1 mounted on the printed circuit board. Since the bandpass filter of the present invention is stable against floating of the ground, it is possible to suppress changes in the characteristics of the filter depending on the mounting state of the mounting portion.

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) Embodiment 1 of the present invention
Are formed as shown in FIG. That is, the ring resonator 1 including the pattern inductor 15a, the resonance capacitor 16a connected in parallel with the pattern inductor 15a, and the input / output terminal 18a connected from the pattern inductor 15a through the coupling capacitor 17a.
9a, a pattern inductor 15b, and a resonance capacitor 16 connected in parallel with the pattern inductor 15b.
b and a ring resonator 19b composed of an input / output terminal 18b connected from the pattern inductor 15b through a coupling capacitor 17b.

The coupling adjusting means 35 is the pattern inductor 1
A linear adjustment piece 37 formed in a pattern is formed in parallel with the opposing sides 36a, 36b of the 5a and 15b, and is located above the center line 21 passing through the center of the opposing sides 36a, 36b (in the present embodiment. Then, the pattern inductor 15a,
A through hole 38 is formed above the upper side of 15b) and is connected to a ground plane formed on the back side of the substrate by this through hole 38. In this way, the ring resonator 19a, the ring resonator 19b and the coupling adjusting means 3 are provided.
5 and 5 are provided on the substrate to form a bandpass filter.

Here, the pattern inductor 15a and the pattern inductor 15b are substantially quadrangular with a length of 12 mm and a width of 8 mm, and the coupling adjusting means 35 is provided in the coupling portion 20 facing each other on one side. Have On the ring resonator 19a side, a resonance capacitor 16a is provided on the lower side (in the drawing) adjacent to the coupling portion 20. An input / output terminal 18a is provided on the opposite side of the resonance capacitor 16a from the coupling section 20 (that is, on the positive phase terminal 22a side) via the coupling capacitor 17a. In addition, the ring resonator 19b
On the side, a resonance capacitor 16b is provided on the lower side adjacent to the coupling portion 20. An input / output terminal 18b is provided on the opposite side of the resonance capacitor 16b from the coupling section 20 (that is, on the positive phase terminal 22b side) through the coupling capacitor 17b.

As described above, the coupling portion 2 that couples the substantially square pattern inductors 15a and 15b on opposite sides.
Since the resonance capacitors 16a and 16b are provided on the side adjacent to one side of the coupling portion 20, the mounting positions of the coupling capacitors 16a and 16b are asymmetric with respect to the center line 21 in the drawing. become.

As a result, the two resonators are strongly coupled with each other in a phase opposite to the phase excited by the coupling capacitor 17 in the ring resonator 19, so that the center frequency 24a of the bandpass filter as shown in FIG. On the other hand, the lower attenuation pole 25a and the upper attenuation pole 26a are asymmetric. That is, the distance 27 between the lower attenuation pole 25a and the center frequency 24a
The distance 28a between the center frequency 24a and the upper attenuation pole 26a is larger than a, and the influence of the upper attenuation pole 26a on the center frequency 24a is smaller.

As a result, the insertion loss at the center frequency 24a when the one attenuation pole 25a is brought close to the center frequency 24a can be reduced as compared with the conventional symmetrical case. In FIG. 2, the horizontal axis 30 is the frequency (MHz) and the vertical axis 31 is the attenuation amount (dB).

By forming this pattern, the coupling adjusting means 35 can further move one unnecessary attenuation pole farther from the center frequency. Therefore, since the contribution of the unnecessary attenuation pole to the center frequency is small,
Insertion loss is improved. When a large amount of attenuation on the high frequency side in the vicinity of the pass frequency is required, by sequentially cutting from the tip 37a direction of the adjusting piece 37, as shown in FIG.
The position of 6b can be adjusted. That is, the tip 37a
By cutting off sequentially from, 26b has a center frequency of 2
4b will be sequentially approached.

Further, in FIG. 1, the resonance capacitor 1
Chip components are used for 6a, 16b and the coupling capacitors 17a, 17b. This is because when reflow soldering is performed, the soldering position on the pattern inductors 15a and 15b of the chip component is determined by the self-alignment effect of the reflow solder. By this,
Pattern inductor 15a and pattern inductor 15b
There is no fluctuation in the inductance of the center frequency 24 and the center frequency 24 is stabilized.

In this embodiment, the center frequency 24a is 1 GHz and the bandwidth is 35 MHz.
Further, the distance 27a between the center frequency 24a and the attenuation pole 25a is 100 MHz, and the center frequency 24a and the attenuation pole 26a are
The distance 28a is 200 MHz.

(Second Embodiment) In the second embodiment, FIG.
As shown in FIG.
Is provided. The coupling adjusting means 40 is provided on the opposite sides 36a, 36 of the pattern inductors 15a and 15b.
Projections 41a and 41b projecting toward the center of the coupling portion 20 are formed on the lower side of b.

The tips 4 of the protrusions 41a and 41b
As shown in FIG.
The positions of the attenuation poles 25c and 26c can be adjusted as shown in FIG. That is, by sequentially cutting from the tips 42a and 42b, the attenuation poles 25c and 26c are sequentially separated from the center frequency 24c. In this way, by adjusting the attenuation pole on the low frequency side to a desired frequency, the deterioration of the insertion loss of the center frequency 24c due to the attenuation pole 26c on the high frequency side can be suppressed to a small value while the attenuation frequency on the low frequency side can be increased. The amount of attenuation can be obtained.

Further, by combining the coupling degree adjusting means 35 in the first embodiment and the coupling degree adjusting means 40 in the second embodiment, the adjustment range can be further increased.

(Third Embodiment) In the third embodiment, the position of the lower attenuation pole 25d with respect to the center frequency 24d is separated from the position of the upper attenuation pole 26d to be asymmetrical. That is, it is the opposite of the first and second embodiments.

In order to realize the bandpass filter having such a property, as shown in FIG. 6, the resonance capacitor 16 is used.
a and the coupling portion 20 (that is, the resonance capacitor 16a
From the negative phase terminal 23a) to the input / output terminal 18a via the coupling capacitor 17a. Further, the input / output terminal 18b is connected between the resonance capacitor 16b and the coupling portion 20 (that is, on the opposite phase terminal 23b side of the resonance capacitor 16b) via the coupling capacitor 17b.

By connecting in this way, as shown in FIG. 7, the attenuation pole 25 below the center frequency 24d is formed.
The position of d can be separated more than the position of the upper attenuation pole 26d.

In this case as well, the coupling degree adjusting means 35 shown in the first embodiment or the coupling degree adjusting means 40 shown in the second embodiment can be used.

(Embodiment 4) In Embodiment 4, as shown in FIG. 8, resonance capacitors 16a and 16b are
Varicap diodes 45a and 45b (used as an example of a variable capacitor) are used. Since the varicap diodes 45a and 45b are used,
By changing the voltage applied from the outside, the center frequency of the bandpass filter can be changed.

That is, the resonance capacitor 1 of the first embodiment
Instead of 6a, the cathode side of the varicap diode 45a is inserted with the coupling portion 20 side, and its anode side is connected to the ground with a choke coil (this may be a high impedance element for a signal, for example, a resistor) 46a. The cathode side is connected to the control voltage supply terminal 49 by a choke coil 47a. Similarly, instead of the resonance capacitor 16b, a varicap diode 45b is provided.
The cathode side is connected to the coupling portion 20 side, the anode side is connected to the ground by the choke coil 46b, and the cathode side is connected to the control voltage supply terminal 49 by the choke coil 47b.

In this way, the varicap diode 45
Since both a and 45b are connected to one control voltage supply terminal 49, the center frequency 24e of the bandpass filter is changed by controlling the voltage applied to this control voltage supply terminal 49, as shown in FIG. It can be freely varied over the width 50.

It is possible to finely adjust the passage characteristic by changing only one of the varicap diodes, for example, 45a. Reference numerals 25e and 26e respectively denote lower and upper attenuation poles of the center frequency 24e.

In this case as well, the coupling degree adjusting means 40 shown in the third embodiment can be used.

(Fifth Embodiment) The fifth embodiment is different from the fourth embodiment shown in FIG. 8 in that the coupling capacitor 48a,
This is the case where a varicap diode is used for both 48b.

When the center frequency is changed by using the resonance capacitors 45a and 45b, the passing waveforms are different when the center frequency 24a is low and when the center frequency 24e is high, as shown in FIG. That is, when the center frequency is high, the pass band width becomes wide, as indicated by 24e. In order to make the pass band widths substantially the same regardless of whether the center frequency is low or high, the coupling capacitor 48a,
48b is corrected by using a varicap capacitor.

The varicap capacitors 48a, 4a
8b may be used for either one, and the other may be a fixed capacitor or both may be varicap capacitors.

In this embodiment, both varicap capacitors 48a and 48b are used for accurate waveform adjustment.

(Embodiment 6) In Embodiment 6, a bandpass filter is modularized. In FIG. 10, 51 is an alumina substrate, and this alumina substrate 5
A bandpass filter is formed on the surface of No. 1. The back surface of the alumina substrate 51 is a ground plane. A metal shield case 52 covers the bandpass filter. And the side surface 52
a is brought into contact with the side surface electrode 51a of the alumina substrate 51 and soldered. Also, in this module, the input / output terminals 18a and 18b are formed on the side surface of the alumina substrate 51,
Surface mounting is possible.

As described above, since the band-pass filter has the module shape, the automatic mounting becomes easy and the management becomes easy. Further, since the alumina substrate is used and the shield case 52 is further used, dielectric loss,
Both radiation loss can be suppressed to be small, pass loss can be reduced, and attenuation at the attenuation pole can be increased. In addition, there is no disturbance from the outside, and no disturbance is given to the outside.

Although an alumina substrate is used in this embodiment, a Teflon substrate can also be used, and the same effect is obtained.

(Embodiment 7) In Embodiment 7, a method of manufacturing the shield case 52 will be described. In FIG. 11A, reference numeral 53 is a tin plate, and the mold 54 is lowered and cut. Burrs 55 are generated downward during this cutting.

Next, as shown in FIG. 11B, the mold 5
By bending in the cutting direction at 6, the side surface 52a of the shield case 52 is formed as shown in FIG. 11C, and the shield case 52 is completed.

Then, as shown in FIG. 11D, the side surface 52a of the shield case 52 is brought into contact with the side surface electrode 51a of the alumina substrate 51 for reflow soldering. At this time, a gap 56 is formed between the side surface 52a and the side surface electrode 51a due to the burr 55. Therefore, the solder 57 is filled by the void 56 due to the capillary phenomenon. Therefore, firm soldering can be performed, and electrical conduction performance can be improved, resulting in an excellent shield effect.

(Embodiment 8) Embodiment 8 is a high frequency device using the bandpass filter of the present invention. As shown in FIG. 12, this high-frequency device has an input terminal 61 to which a high-frequency signal is input, a fixed input filter 62 to which the signal input to the input terminal 61 is supplied, and an output of the input filter 62. Mixer 64 to which the output of the local oscillator 63 is connected to the other input, the bandpass filter 65 of the present invention to which the output of the mixer 64 is supplied, and the bandpass filter 65.
Of the local oscillator 66 is connected to the other input, and the output terminal 68 to which the output of the mixer 67 is supplied.

Here, as shown in FIG. 13, the mixer 64
The intermediate frequency 69, which is the output of, is higher than the frequency 70 of the local oscillator 63. In this case, as the bandpass filter 65, the one shown in the first embodiment or the second embodiment is used. That is, with respect to the center frequency 24f, the lower attenuation pole 23 is the upper attenuation pole 2
Image interference 71 is removed by using a value closer than 4.
This reduces the loss of the pass band and eliminates image interference. That is, the image interference 71 is adjusted so as to be the lower attenuation pole 23.

When the intermediate frequency 69 which is the output of the mixer 64 is lower than the frequency of the local oscillator 63, the bandpass filter 65 shown in the third embodiment is used. . That is, the upper attenuation pole 26
Remove the image disturbance with d. This reduces the loss of the pass band and eliminates image interference. Thus, the bandpass filter of the present invention exerts its effect particularly when used as an intermediate frequency filter.

(Embodiment 9) Embodiment 9 is an example in which the bandpass filter of the present invention is used in a single super receiver. That is, as shown in FIG. 14, the high-frequency device of the present invention is supplied with an input terminal 71 to which a high-frequency signal is input and a signal input to the input terminal 71.
An input filter 72 whose center frequency is variable, a mixer 74 in which the output of the input filter 72 is supplied to one input and the output of a local oscillator 73 is connected to the other input, and a mixer 74 of this mixer 74 The bandpass filter 75 of the present invention to which the output is supplied, and this bandpass filter 7
5 is supplied to the output terminal 76.

Therefore, since the filter of the present invention is used as the intermediate frequency filter 75 of the single super receiver, adjacent interference signals can be removed and the insertion loss in the pass band can be reduced.

(Embodiment 10) Embodiment 10 is an example in which a bandpass filter having a variable center frequency according to the present invention is used as an input filter of a high frequency device. 15, a high frequency device of the present invention includes an input terminal 81 to which a high frequency signal is input, and a band pass filter of the present invention connected to the input terminal 81 and having a variable center frequency (Embodiment 4 or Embodiment 4). 82), a mixer 84 in which the output of the bandpass filter 82 is supplied to one input and the output of the local oscillator 83 is connected to the other input, and the output of the mixer 84 is The PLL circuit 8 includes a supplied bandpass filter 85, an output terminal 86 to which the output of the bandpass filter 85 is supplied, a local oscillator 83, and a PLL circuit 87 loop-connected.
The output of No. 7 is supplied to the control voltage supply terminal 49 of the bandpass filter 82 of the present invention. Here, the bandpass filter 85 may also use the bandpass filter of the present invention.

Therefore, since the center frequency can be electrically controlled, it can be used as an input filter of a single super receiver.

(Embodiment 11) In Embodiment 11, as shown in FIG. 16, a metal frame 91 and a printed circuit board 93 mounted in the frame 91 via mounting portions 92a to 92d, The band pass filter 94 of the present invention is mounted on the printed circuit board 93.

Here, the bandpass filter of the present invention is
The equivalent circuit is as shown in FIG. That is, corresponding to FIG. 1, the ring resonators 19a and 19b are the mutual inductor 99 due to the even mode current component of the pattern inductor at the coupling portion and the equivalent capacitor 9 due to the odd mode current component.
It is connected by 5 and 96. Since this coupling is asymmetric, the capacitors 95 and 96 have different capacities. That is, for example, the capacitance of the capacitor 96 is larger than that of the capacitor 95.

Further, since this bandpass filter is provided on the printed circuit board 93, distributed capacitances 97 and 98 are equivalently generated between the pattern inductors 15a and 15b and the back surface of the printed circuit board 93. In the bandpass filter including the ring resonators 19a and 19b according to the present invention, the resonance frequencies are almost equal to those of the resonance capacitors 16a and 1b.
Since it is almost determined by the parallel resonance of 6b and the pattern inductors 15a and 15b, it is stable against floating of the distributed capacitors 97 and 98 to the ground.

Therefore, the present bandpass filter has a mounting portion 9
Since it is unlikely to be affected by other influences such as 2a to 92d (board ground, etc.), it is stable against variations in mass production of the mounting portions 92a to 92d, and the degree of freedom in mounting the printed circuit board 93 on the frame 91 increases.

[0072]

As described above, according to the present invention, there is provided a coupling portion which is coupled on one side of the substantially rectangular pattern inductance facing each other, and a resonance capacitor is provided on the side adjacent to one side of the coupling portion. Therefore, the mounting position of the resonance capacitor is asymmetrical, and the positions of the attenuation poles generated above and below the center frequency of the bandpass filter are also asymmetrical.

Further, by providing the coupling degree adjusting means formed in a pattern at a position eccentric from the coupling center,
The attenuation pole can be controlled, and the insertion loss at the center frequency when one of the attenuation poles is brought close to the center frequency can be reduced as compared with the conventional symmetrical case. Therefore,
A bandpass filter with less passage loss can be realized.

[Brief description of drawings]

FIG. 1 is a plan view of a bandpass filter according to a first embodiment of the present invention.

FIG. 2 is a first characteristic diagram of the same.

FIG. 3 is a second characteristic diagram of the same.

FIG. 4 is a plan view of a bandpass filter according to a second embodiment of the present invention.

[Figure 5] Same as above

FIG. 6 is a plan view of the bandpass filter according to the third embodiment.

FIG. 7 is a characteristic diagram of the same.

FIG. 8 is a plan view of the bandpass filter according to the fourth embodiment.

FIG. 9 is a characteristic diagram of the same.

FIG. 10 is a perspective view of the bandpass filter according to the sixth embodiment.

FIG. 11A is a first process drawing showing a bandpass filter manufacturing method according to a seventh embodiment, FIG. 11B is a second process drawing showing the same filter manufacturing method, and FIG. The 3rd process drawing (d) showing a method is the 4th process drawing showing the filter manufacturing method.

FIG. 12 is a block diagram of a high frequency device using the bandpass filter of the present invention according to the eighth embodiment.

FIG. 13 is a characteristic diagram of the same.

FIG. 14 is a block diagram of a high frequency device using a bandpass filter of the present invention according to the ninth embodiment.

FIG. 15 is a block diagram of a high frequency device using the bandpass filter of the present invention according to the tenth embodiment.

FIG. 16 is a plan view of a high frequency device using the bandpass filter of the present invention according to the eleventh embodiment.

FIG. 17 is an equivalent circuit diagram of the same bandpass filter.

FIG. 18 is a circuit diagram of a conventional bandpass filter.

FIG. 19 is a characteristic diagram of the same.

[Explanation of symbols]

15a pattern inductor 15b pattern inductor 16a Resonant capacitor 16b Resonant capacitor 17a Coupling capacitor 17b Coupling capacitor 18a Input / output terminal 18b I / O terminal 19a ring resonator 19b ring resonator 20 connection 21 center line 22a Positive phase terminal of resonance capacitor 22b Positive phase terminal of resonance capacitor 23a Reverse-phase terminal of resonance capacitor 23b Negative-phase terminal of resonance capacitor 35 Coupling adjusting means 37 Adjustment piece 37a Tip of adjustment piece 38 through hole

Continued front page    (72) Inventor Hitoshi Hirano             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5J006 HB01 HB03 HB16 HD07 JA01                       JA11 LA02 LA03 MA07 MA09                       NA04 NC01 NE16

Claims (18)

[Claims] 1. A first pattern inductor and the first pattern inductor.
Ring resonance composed of a first resonance capacitor connected in parallel with the pattern inductor and a first input / output terminal connected from the first pattern inductor via a first coupling capacitor. , A second pattern inductor, a second resonance capacitor connected in parallel with the second pattern inductor, and a second connection from the second pattern inductor via a second coupling capacitor. A second ring resonator including an input / output terminal of the second ring resonator, and the first ring resonator and the second ring resonator.
In the bandpass filter in which the ring resonator is provided on the substrate, the first pattern inductor and the second pattern inductor have a substantially quadrangular shape, and a coupling portion in which one side of each pattern inductor faces each other. Have
The first resonance capacitor and the second resonance capacitor are provided on the respective sides adjacent to and corresponding to the coupling portion, and the first resonance capacitor is provided in the vicinity of the first resonance capacitor through the first coupling capacitor. The first input / output terminal is provided, and the second input / output terminal is provided from near the second resonance capacitor through the second coupling capacitor, and is eccentric from the center of the coupling portion. A bandpass filter provided with a coupling degree adjusting means formed in a pattern at a position. 2. The bandpass filter according to claim 1, wherein the coupling degree adjusting means is linearly provided in a pattern on the centerline of the coupling portion, and one end thereof is connected to the ground. 3. The bandpass filter according to claim 1, wherein the coupling degree adjusting means is formed with a convex portion projecting from each pattern inductor toward the corresponding pattern inductor. 4. The bandpass filter according to claim 2, wherein each of the pattern inductors has a convex portion that protrudes toward the corresponding pattern inductor. 5. The bandpass filter according to claim 1, wherein at least the first resonance capacitor and the second resonance capacitor use chip parts, and these chip parts are reflow-soldered with cream solder. 6. The bandpass filter according to claim 1, wherein the input / output terminal is provided on the side opposite to the coupling portion with respect to the resonance capacitor. 7. The bandpass filter according to claim 1, wherein the input / output terminal is provided on the coupling portion side with respect to the resonance capacitor. 8. The bandpass filter according to claim 1, wherein at least one of the first resonance capacitor and the second resonance capacitor is a variable capacitor. 9. A varicap diode is used for the first resonance capacitor and the second resonance capacitor, and a voltage is supplied to each varicap diode from one control voltage supply terminal. Bandpass filter. 10. The bandpass filter according to claim 9, wherein at least the first coupling capacitor or the second coupling capacitor uses a varicap capacitor. 11. The bandpass filter according to claim 1, wherein the substrate is an alumina substrate or a Teflon (registered trademark) substrate. 12. The bandpass filter according to claim 1, wherein the bandpass filter has a module shape and is surface mountable. 13. The bandpass filter according to claim 12, wherein the module is covered with a metal shield case. 14. The bandpass filter according to claim 13, wherein the shield case is cut with a mold, bent in the cutting direction, and brought into contact with an electrode formed on a side surface of the substrate. 15. An input terminal, a first mixer to which a signal input to this input terminal is supplied to one input, and the output of a first local oscillator is connected to the other input, The bandpass filter according to claim 1, wherein the output of the first mixer is supplied, and the output of the bandpass filter is supplied to one input and the output of the second local oscillator is supplied to the other input. A second mixer connected,
A high frequency device having an output terminal to which the output of the second mixer is supplied. 16. An input terminal, an input filter to which a signal input to this input terminal is supplied, an output signal of this input filter is supplied to one input, and an output of a local oscillator is supplied to the other input. A high-frequency device having a mixer connected thereto, the bandpass filter according to claim 1 to which an output signal of the mixer is supplied, and an output terminal to which an output of the bandpass filter is supplied. 17. The bandpass filter according to claim 9, wherein an input terminal and a signal input to the input terminal are supplied, and the output of the bandpass filter is supplied to one input and the other input. A high-frequency device having a mixer to which the output of the local oscillator is connected, and an output terminal to which the output of the mixer is supplied. 18. A high-frequency device comprising a metal frame, a printed circuit board mounted in the frame via a mounting portion, and the bandpass filter according to claim 1 mounted on the printed circuit board.