JP2000357902A - Planar filter, duplexer using the same, high frequency module using them and communications equipment using the module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar filter where an attenuation pole can be formed near the low area of a pass band. SOLUTION: Two quarter-wave strip line resonators 11 and 13 are arranged on both sides across a half-wave strip line resonator 4. The opening end sides are arranged near the two different opening ends of the half-wave strip line resonator 4. Ground end sides are bent to the directions of the half-wave strip line resonator 4 at nearby parts of the center of the half-wave strip line resonator 4 and ground ends are mutually counterposed. Thus, an attenuation pole is installed near the low area side of a pass band and the attenuation characteristic of a plane filter can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar filter, a duplexer using the same, a high-frequency module using the same, and a communication device using the same, and more particularly, a planar filter for a radio communication device, a duplexer using the same and the same. The present invention relates to a high-frequency module used and a communication device using the same.

[0002]

2. Description of the Related Art FIG. 12 shows a conventional planar filter.
In FIG. 12, a planar filter 1 is formed by forming a ground electrode (not shown) on the entire surface of one main surface of a dielectric substrate 9 and forming some electrode patterns constituting the filter on the other main surface. Have been.

Here, FIG. 13 shows an electrode pattern of the flat filter 1, and the configuration of the flat filter 1 will be described with reference to FIG. The plane filter 1 has a quarter-wavelength strip line resonator 2 having one open end and the other end connected to a ground electrode via a through hole 3 to serve as a ground end, and a half-wavelength end having an open end. It is composed of a stripline resonator 4 and three electrode patterns of a quarter-wavelength stripline resonator 5 whose one end is an open end and the other end is connected to a ground electrode through a through hole 6 and is used as a ground end. I have. The 波長 wavelength stripline resonators 2 and 5 are arranged in parallel with the １ ／ wavelength stripline resonator 4 interposed therebetween. In addition, the open ends of the quarter-wavelength stripline resonators 2 and 5 are arranged near two different open ends of the half-wavelength stripline resonator 4, and The ground terminal 5 is arranged near the center of the half-wavelength strip line resonator 4. The quarter-wavelength stripline resonator 2 is connected to the input terminal 7 from the middle of the line, and the quarter-wavelength stripline resonator 5 is connected to the output terminal 8 from the middle of the line.

[0004] The planar filter 1 configured as described above has
Each resonator is magnetically coupled via a portion arranged in parallel to function as a three-stage bandpass filter.

FIG. 14 shows the insertion loss (I
L) and frequency characteristics of return loss (RL). This means that the center frequency is 5.2 GHz and the pass bandwidth is about 40
In the 0 MHz band-pass filter, there is no attenuation pole near the high band side or the low band side of the pass band.

[0006]

However, the planar filter 1 has a problem that the attenuation characteristic near the pass band is poor because no attenuation pole exists near the pass band. By disposing the open ends of the two quarter-wavelength stripline resonators near the same open end of the half-wavelength stripline resonator, an attenuation pole is provided near the high band side of the passband. However, it is not possible to provide an attenuation pole near the lower side of the pass band or to provide an attenuation pole near both the lower side and the higher side of the pass band. Therefore, there is a problem that the attenuation characteristics near the pass band cannot be sufficiently improved.

Therefore, in the present invention, a flat filter capable of providing an attenuation pole near the low band side of the pass band or near both the low band side and the high band side, a duplexer using the same, and a duplexer using the same are used. Provided are a high-frequency module and a communication device using the same.

[0008]

In order to achieve the above object, a planar filter according to the present invention comprises a half-wavelength stripline resonator having both ends open, and both sides sandwiching the half-wavelength stripline resonator. In at least a part of the 1 /
It consists of two quarter-wavelength stripline resonators arranged substantially in parallel with the two-wavelength stripline resonator, and the two quarter-wavelength stripline resonators have an open end on the half side.
The wavelength strip line resonator is disposed near two different open ends, respectively, and the ground end side is located near the center of the half wavelength strip line resonator.
It is characterized by being bent in the direction of a two-wavelength stripline resonator and having grounded ends facing each other.

Further, in the planar filter according to the present invention, the open ends of the two quarter-wavelength stripline resonators may be bent in the direction of the half-wavelength strip resonator, and the half-wavelength stripline may be bent. It is characterized in that the resonators are brought close to two different open ends, respectively.

Further, in the planar filter according to the present invention, the open ends of the two quarter-wave strip line resonators may be connected to the one-quarter wavelength strip line resonators.
The two-wavelength stripline resonator is characterized by being opposed to mutually different open ends.

Further, a planar filter according to the present invention is characterized in that it has a plurality of the half-wavelength stripline resonators.

Also, a duplexer according to the present invention is characterized in that two of the above-described planar filters are connected.

A high-frequency module according to the present invention is characterized by using the above-mentioned planar filter or duplexer.

Further, a communication device according to the present invention is characterized by using the above-mentioned high-frequency module.

With this configuration, the planar filter of the present invention can improve the attenuation characteristics by providing attenuation poles on the lower side of the pass band or on both the lower side and the higher side.

Further, in the duplexer of the present invention,
Sufficient isolation between the transmitting side and the receiving side can be obtained.

Further, in the high-frequency module of the present invention, the circuit configuration can be simplified to reduce the size and cost.

Further, in the communication device of the present invention, downsizing and cost reduction can be achieved.

[0019]

FIG. 1 shows an embodiment of a planar filter according to the present invention. FIG. 2 shows a configuration of an electrode pattern of the flat filter shown in FIG. 1 and 2, the same or equivalent parts as those in FIGS. 12 and 13 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1 and FIG.
Reference numeral 0 denotes a quarter-wavelength strip line resonator 11 having one open end and the other end connected to a ground electrode via a through hole 12 to serve as a ground end, and one end having an open end and the other end having a through hole 14. Is connected to the ground electrode via
Two of the four-wavelength stripline resonators 13 are arranged with the half-wavelength stripline resonator 4 interposed therebetween. Here, the 波長 wavelength strip line resonator 11
Is formed in an L-shape, most of the portions including the open end are arranged in parallel with the half-wavelength stripline resonator 4, and the ground end is bent in the direction of the half-wavelength stripline resonator 4. I have. The quarter-wavelength stripline resonator 13 is also formed in an L-shape, and most of the portions including the open ends are 1 /
It is arranged in parallel with the two-wavelength stripline resonator 4, and the ground end is bent in the direction of the half-wavelength stripline resonator 4. The open ends of the quarter-wavelength stripline resonators 11 and 13 are arranged near two different open ends of the half-wavelength stripline resonator 4, respectively. And 13 are arranged near the center of the half-wavelength stripline resonator 4. as a result,
The ground end of the quarter wavelength strip line resonator 11 and the quarter
The ground ends of the wavelength strip line resonators 13 are configured to face each other with the center of the half wavelength strip line resonator 4 interposed therebetween.

In the planar filter 10 configured as described above, the resonators are magnetically coupled via portions arranged in parallel to function as a three-stage bandpass filter.

FIG. 3 shows the frequency characteristics of the insertion loss (IL) and the reflection loss (RL) of the planar filter 10. As shown in FIG. 3, in the planar filter 10,
An attenuation pole p1 exists near the lower side of the pass band. As a result, the amount of attenuation near the low-pass side of the pass band increases, and the attenuation characteristics are improved.

FIG. 4 shows another embodiment of the planar filter of the present invention. FIG. 4 shows an electrode pattern, and a perspective view corresponding to FIG. 1 is omitted since it is the same as FIG. 1 except for the shape of the electrode pattern. In FIG. 4, the same or equivalent parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 4, a planar filter 20 has a quarter-wavelength strip line resonator 21 having one end open and the other end connected to a ground electrode via a through hole 22 to serve as a ground, and one end connected to a ground. Two open quarter-wavelength stripline resonators 23 whose open ends are connected to the ground electrode via the through holes 24 and whose ground ends are used, sandwich the half-wavelength stripline resonator 4 therebetween. It is arranged and arranged. Here, the quarter-wavelength stripline resonator 21 is formed in a U-shape, the central part of the line is arranged in parallel with the half-wavelength stripline resonator 4, and the open end side and the ground end side are 1/1/2.
It is bent and arranged in the direction of the two-wavelength stripline resonator 4. In addition, a 1/4 wavelength strip line resonator 2
3 is also formed in a U-shape, the central portion of the line is arranged in parallel with the half-wavelength stripline resonator 4, and the open end and the ground end are bent in the direction of the half-wavelength stripline resonator 4. Are located. The open ends of the quarter-wavelength stripline resonators 21 and 23 are arranged near two different open ends of the half-wavelength stripline resonator 4, respectively. And 23 are disposed near the center of the half-wavelength stripline resonator 4. As a result, the open end of the quarter wavelength strip line resonator 21 is
The open end of the 波長 wavelength strip line resonator 23 is １ ／
The wavelength strip line resonator 4 is configured to be close to two different open ends. Also, 1
The ground end of the 波長 wavelength strip line resonator 21 and the ground end of the 波長 wavelength strip line resonator 23 face each other with the center of the 波長 wavelength strip line resonator 4 interposed therebetween.

In the planar filter 20 configured as described above, the resonators are magnetically coupled via the portions arranged in parallel to function as a three-stage bandpass filter. Furthermore, the open ends of the quarter-wavelength stripline resonator 21 and the open ends of the quarter-wavelength stripline resonator 23 and the vicinity of the two open ends of the half-wavelength stripline resonator 4 are respectively provided. Capacitance is formed, 1/2
The wavelength stripline resonator 4 and the two quarter-wavelength stripline resonators 21 and 23 are also capacitively coupled, and this is one of the factors that determine the characteristics of the bandpass filter.

FIG. 5 shows the frequency characteristics of the insertion loss (IL) and the reflection loss (RL) of the planar filter 20. As shown in FIG. 5, in the planar filter 20,
An attenuation pole p2 is provided near both the low band side and the high band side of the pass band.
p3 exists. Therefore, the amount of attenuation in the vicinity of both the low band side and the high band side of the pass band increases, and the attenuation characteristics are improved.

FIG. 6 shows still another embodiment of the planar filter of the present invention. FIG. 6 shows an electrode pattern, and a perspective view is omitted as in the embodiment shown in FIG. FIG.
In FIG. 7, the same or equivalent portions as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 6, a planar filter 30 has a quarter-wavelength strip line resonator 31 having one end open and the other end connected to a ground electrode via a through hole 32 to serve as a ground, and one end connected to a ground. Two of the quarter-wavelength stripline resonators 34 having open ends and the other end connected to a ground electrode via through holes 35 and used as ground ends, both ends being １ ／ of the open end
The wavelength strip line resonator 33 is interposed therebetween. Here, the 波長 wavelength strip line resonator 31 is formed in a U-shape, and the center of the line is disposed parallel to the center of the 波長 wavelength strip line resonator 33, and the open end side and the ground end side Are bent in the direction of the half-wavelength stripline resonator 33 and disposed. Also, 1
The 波長 wavelength strip line resonator 34 is also formed in a U-shape, and the central portion of the line is disposed parallel to the central portion of the 波長 wavelength strip line resonator 33, and the open end side and the ground end side are １ ／. It is bent and arranged in the direction of the wavelength strip line resonator 33. The open ends of the quarter-wavelength stripline resonators 31 and 34 are arranged to face two different open ends of the half-wavelength stripline resonator 33, respectively. The ground ends of 31 and 34 are arranged near the center of the 波長 wavelength stripline resonator 33. As a result, the ground end of the 1/4 wavelength stripline resonator 31 is
The ground end of the 波長 wavelength strip line resonator 34 is １ ／
The wavelength strip line resonators 33 are configured to face each other with the center part interposed therebetween.

In the planar filter 30 configured as described above, the resonators are magnetically coupled via the portions arranged in parallel to function as a three-stage bandpass filter. Further, the open ends of the 波長 wavelength strip line resonator 31 and the ４ wavelength strip line resonator 34 and the two open ends of the 波長 wavelength strip line resonator 33 are respectively static. A capacitance is formed, and the 波長 wavelength stripline resonator 33 and the two １ ／ wavelength stripline resonators 31 and 34 are also capacitively coupled, which also determines the characteristics as a bandpass filter. This is one of the factors.

FIG. 7 shows frequency characteristics of the insertion loss (IL) and the reflection loss (RL) of the planar filter 30. As shown in FIG. 7, in the planar filter 30,
Attenuation poles p4 near both the low band side and the high band side of the pass band,
p5 is present. As a result, the amount of attenuation in the vicinity of both the low band side and the high band side of the pass band increases, and the attenuation characteristics are improved.

Further, since the open ends of the two quarter-wavelength stripline resonators 31 and 34 are opposed to the two open ends of the half-wavelength stripline resonator 33, respectively, the capacitance between them is reduced. The coupling is stronger than in the case of the planar filter 20 shown in FIG. When the capacitive coupling between the open ends of the quarter-wavelength stripline resonator and the half-wavelength stripline resonator becomes strong, the magnetic field coupling in the parallel portion of the two resonators becomes weak.
Therefore, the interval between the quarter-wavelength stripline resonator and the half-wavelength stripline resonator can be reduced, and the size of the planar filter 40 can be reduced.

As can be seen from FIG. 6, the center line of the ground end of the quarter wavelength strip line resonator 31 and the quarter line
The center line of the ground end of the wavelength strip line resonator 34 is slightly shifted. As described above, the ground ends of the two quarter-wavelength strip line resonators may face each other with a slight shift.

FIG. 8 shows still another embodiment of the planar filter of the present invention. FIG. 8 shows an electrode pattern, and a perspective view is omitted as in the embodiments shown in FIGS. In FIG. 8, the same or equivalent portions as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 8, the plane filter 40 is
A four-wavelength stripline resonator 21 and a quarter-wavelength stripline resonator 23 are arranged with half-wavelength stripline resonators 41 and 42 having open ends at both ends. The arrangement relationship between the quarter-wavelength stripline resonator 21 and the quarter-wavelength stripline resonator 23 is the same as that of the planar filter 20 shown in FIG.

The planar filter 40 configured as described above functions as a four-stage bandpass filter by using two half-wavelength stripline resonators. By increasing the number of stages, the attenuation characteristics near both sides of the pass band can be made steeper, and the amount of attenuation can be further increased.

In the plane filter 40, 1 /
Although the number of two-wavelength stripline resonators is two, three or more half-wavelength stripline resonators may be used.

In each of the above embodiments, the strip line resonator is formed by a so-called microstrip line in which a ground electrode is formed on one main surface of the dielectric substrate and an electrode pattern is formed on the other main surface. However, it may be a strip line of a triplate structure in which ground electrodes are formed on both one main surface and the other main surface of the dielectric substrate and an electrode pattern is formed therebetween,
The same operation and effect as those of the microstrip line can be obtained.

The through-hole for forming the ground end of the quarter-wavelength stripline resonator is not limited to the through-hole, but may be a via-hole in which the inside of the hole is filled with an electrode material or the like. Things.

FIG. 9 is a block diagram showing one embodiment of a duplexer formed by using the planar filter of the present invention. 9, a duplexer 50 includes two planar filters 51 and 52 of the present invention having different frequency bands from each other, and an output terminal of the planar filter 51 and a planar filter 52.
Are connected to the antenna terminal 53, and the input terminals of the planar filter 51 are the transmitting terminal 54 and the planar filter 5
The second output terminal is configured as the receiving terminal 55.

The duplexer 50 constructed as described above
Means that the antenna terminal 53 is an external antenna and the transmitting terminal 5
4 is connected to the transmitting circuit, and the receiving terminal 55 is connected to the receiving circuit, respectively, to constitute a communication device. When transmitting and receiving using a common external antenna, a transmitted signal enters the receiving circuit or a received signal enters the transmitting circuit. Prevent slurping. In particular, by using the planar filter of the present invention, the attenuation of the other band-pass filter in the pass band of one band-pass filter can be increased. Can be sufficiently isolated.

FIG. 10 shows an embodiment of a high-frequency module using the band-pass filter of the present invention. 10, a high-frequency module 60 includes a planar filter 10 of the present invention as an RF filter, an RF amplifier 61,
Local oscillator 62, mixer 63, IF filter 64, IF
This is a down converter including an amplifier 65 and an input terminal 66 and an output terminal 67. Here, the input terminal 66
Is connected to the mixer 63 via the plane filter 10 and the RF amplifier 61 in this order. The local oscillator 62 is also connected to the mixer 63. The output of the mixer 63 is connected to an output terminal 67 via an IF filter 64 and an IF amplifier 65 in this order.

The high-frequency module 6 configured as described above
At 0, since the flat filter 10 of the present invention is used, a large amount of attenuation in the attenuation range can be obtained, so that it is not necessary to use another component such as a notch filter for compensating for the insufficient amount of attenuation. In addition, an input matching circuit such as an RF amplifier connected at a subsequent stage can be simplified. As a result, the high-frequency module 60 can be reduced in size and cost.

It is to be noted that in FIG.
The high-frequency module 60 is configured by using FIG.
The high-frequency module may be configured by using the planar filters 20, 30, 40 and the duplexer 50 shown in 6, 8, and 9, and have the same effect.

FIG. 11 shows an embodiment of a communication device constituted by using the high-frequency module of the present invention. In FIG. 11, a communication device 70 includes a high-frequency module 60 of the present invention,
It comprises an antenna 71 and a signal processing circuit 72.
Here, the antenna 71 is connected to the high-frequency module 60, and the high-frequency module 60 is connected to the signal processing circuit 72.

In the communication device 70 configured as described above, by using the high-frequency module 60 of the present invention, size reduction and cost reduction can be achieved.

[0046]

According to the planar filter of the present invention, two filters are provided on both sides of a half-wavelength strip line resonator open at both ends.
Two quarter-wavelength stripline resonators arranged at least partially in parallel with the half-wavelength stripline resonator;
The open ends are respectively disposed near two different open ends of the half-wavelength stripline resonator, and the ground end is located near the center of the half-wavelength stripline resonator. By bending and facing the line resonator in the direction of the line resonator, an attenuation pole can be provided near the lower band side of the pass band.

The open ends of the two quarter-wavelength stripline resonators are bent in the direction of the half-wavelength strip resonators, and are respectively located near different open ends of the half-wavelength stripline resonators. By making them close to each other, attenuation poles can be provided near both sides of the pass band.

Also, by making the open ends of the two quarter-wavelength strip line resonators face the different open ends of the half-wavelength strip line resonator, respectively.
The size can be reduced.

Further, by having a plurality of half-wavelength stripline resonators, the attenuation characteristics in the attenuation region can be further improved.

According to the duplexer of the present invention, by using the planar filter of the present invention, sufficient isolation between the transmitting side and the receiving side can be obtained.

According to the high-frequency module of the present invention, the size and cost can be reduced by using the planar filter and the duplexer of the present invention.

Further, according to the communication device of the present invention, the size and cost can be reduced by using the high-frequency module of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing one embodiment of a flat filter of the present invention.

FIG. 2 is a diagram showing a configuration of an electrode pattern of the flat filter of FIG.

FIG. 3 is a diagram illustrating characteristics of the planar filter of FIG. 1;

FIG. 4 is a diagram showing a configuration of an electrode pattern of another embodiment of the planar filter of the present invention.

FIG. 5 is a diagram illustrating characteristics of the planar filter of FIG. 4;

FIG. 6 is a diagram showing a configuration of an electrode pattern of still another embodiment of the planar filter of the present invention.

FIG. 7 is a diagram illustrating characteristics of the planar filter of FIG. 6;

FIG. 8 is a diagram showing a configuration of an electrode pattern of still another embodiment of the planar filter of the present invention.

FIG. 9 is a block diagram showing one embodiment of the duplexer of the present invention.

FIG. 10 is a block diagram showing one embodiment of the high-frequency module of the present invention.

FIG. 11 is a block diagram showing one embodiment of the communication device of the present invention.

FIG. 12 is a schematic perspective view showing a conventional flat filter.

FIG. 13 is a diagram showing a configuration of an electrode pattern of the flat filter of FIG.

FIG. 14 is a diagram showing characteristics of the planar filter of FIG.

[Explanation of symbols]

4, 33, 41, 42 １ ／ wavelength strip line resonator 7 ８ input terminal 8 出力 output terminal 9 基 体 base body 10, 20, 30, 40 平面 plane filter 11, 13, 21, 23, 31, 34 １ 1 / 4 wavelength stripline resonator 12, 14, 22, 24, 32, 35 through hole 50 duplexer 60 high frequency module 70 communication device

Continuation of the front page F term (reference) 5J006 HB03 HB12 HB13 HB22 JA01 JA13 LA03 NA03 NB07 NC02 NE13 NE14 NE17

Claims (7)

[Claims] 1. A half-wavelength stripline resonator having both ends open, and at least portions of both sides of the half-wavelength stripline resonator sandwiching the half-wavelength stripline resonator at least partially in parallel with the half-wavelength stripline resonator. The two quarter-wavelength stripline resonators are arranged, and the two quarter-wavelength stripline resonators have open ends near two different open ends of the half-wavelength stripline resonator. And the grounding end side is 1
A flat filter characterized by being bent in the direction of the half-wavelength stripline resonator near the center of the half-wavelength stripline resonator and having grounded ends facing each other. 2. An open end side of the two quarter-wavelength stripline resonators is bent in a direction toward the half-wavelength stripline resonator, and two different quarter-wavelength stripline resonators are bent. The planar filter according to claim 1, wherein the planar filters are provided near two open ends. 3. An open end of each of the two quarter-wavelength stripline resonators is opposed to a different open end of the half-wavelength stripline resonator. A flat filter according to item 1. 4. The planar filter according to claim 1, comprising a plurality of said half-wavelength stripline resonators. 5. A duplexer comprising two planar filters according to claim 1 connected to each other. 6. A high-frequency module using the planar filter according to claim 1 or the duplexer according to claim 5. 7. A communication device using the high-frequency module according to claim 6.