CN105207639A - Planar filter device - Google Patents
Planar filter device Download PDFInfo
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- CN105207639A CN105207639A CN201410274118.3A CN201410274118A CN105207639A CN 105207639 A CN105207639 A CN 105207639A CN 201410274118 A CN201410274118 A CN 201410274118A CN 105207639 A CN105207639 A CN 105207639A
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Abstract
The present invention provides a planar filter device, relating to the field of communication technology. The problem of the difficult low-cost and high-efficinecy integration of a planar filter device under the constraint condition of a strictly limited volume in the prior art is solved. The device comprises a U-shaped resonant part, an input transmission line and an output transmission line which are mutually isolated. The U-shaped bottom center of the U-shaped resonant part is provided with a grounding point to form the short circuit point of the U-shaped resonant part. The U-shaped resonant part is divided into a first resonant part and a second resonant part by the grounding point. The top parts of the two U-shaped walls of the U-shaped resonant part are mutually separated to form the breaking point of the U-shaped resonant part. The input transmission line and the output transmission line are at the outer side of the U-shaped resonant part, wherein the input transmission line extends along the first resonant part, and the out transmission line extends along the second resonant part.
Description
Technical field
The present invention relates to communication technical field, particularly relate to a kind of plane filtering device.
Background technology
In wireless communications, antenna receives and send signal all to be needed to coordinate to filter to carry out corresponding filtering, by all complanations integrate the installing space can saving RRU (radioremoteunit, Remote Radio Unit) and reduce feeder loss of antenna and filter.But how under the constraints of such volume very critical, make flat filter can low-cost high-efficiency ground integrated, not good solution in prior art.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of plane filtering device, in order to solve in prior art under the constraints of volume very critical, is difficult to carry out the integrated problem of low-cost high-efficiency to flat filter.
For solving the problems of the technologies described above, on the one hand, the invention provides a kind of plane filtering device, comprising: the U-shaped resonant structure be intervally installed, input transmission line and output transmission line; The U-shaped bottom center of described U-shaped resonant structure is provided with earth point to form the short dot of described U-shaped resonant structure, and described U-shaped resonance portion is the first resonant structure and the second resonant structure by described earth point; The top of two U-shaped walls of described U-shaped resonant structure is separated from each other, to form the trip point of described U-shaped resonant structure; Described input transmission line and described output transmission line are positioned at the outside of described U-shaped resonant structure, wherein, described input transmission line extends along described first resonant structure, be coupled in described U-shaped resonant structure to make the signal in described input transmission line by described first resonant structure, described output transmission line extends along described second resonant structure, to make described signal after resonance between the short dot and trip point of described U-shaped resonant structure, be coupled in described output transmission line by described second resonant structure.
Optionally, capacitor is provided with between the top of two U-shaped walls of described U-shaped resonant structure.
Optionally, described capacitor is fixed capacitor or variable capacitor.
Optionally, the capacitance of described capacitor is between 0 to 0.5 pico farad.
Optionally, the U-shaped arm of described input transmission line and described first resonant structure be coupled as capacitive coupling, being coupled as bottom the U-shaped of described input transmission line and described first resonant structure is inductive coupled; The U-shaped arm of described output transmission line and described second resonant structure be coupled as capacitive coupling, being coupled as bottom the U-shaped of described output transmission line and described second resonant structure is inductive coupled.
Optionally, described U-shaped resonant structure is axisymmetric, and its symmetry axis is through described short dot and is parallel to the straight line of described U-shaped arm.
Optionally, described input transmission line and described output transmission line are about described symmetry axis symmetry.
Optionally, apart 0.28 millimeter, the U-shaped arm of described input transmission line and described first resonant structure, at a distance of 0.23 millimeter bottom the U-shaped of described input transmission line and described first resonant structure; Described input transmission line and described output transmission line bottom described U-shaped 0.25 millimeter apart.
Optionally, the length of described U-shaped resonant structure is the half of wavelength corresponding to the resonance frequency of described filter.
Optionally, the band pass filter means of described plane filtering device to be free transmission range be 1920MHz to 1980MHz.
The plane filtering device that embodiments of the invention provide, the resonant structure being used for carrying out signal filtering is designed to U-shaped, input transmission line and output transmission line are all close to this U-shaped resonant structure, thus compact conformation, the design of short dot and trip point can make signal vibrate in resonant structure, in certain frequency band range centered by resonance frequency, signal can be stored in U-shaped resonant structure with the form of standing wave, thus the signal coupling in passband is gone out by output transmission line, effectively achieve filtering with compact structure and lower cost and be convenient to antenna integrated.
Accompanying drawing explanation
A kind of vertical view of the plane filtering device that Fig. 1 provides for embodiments of the invention;
Fig. 2 is the cutaway view of device along A-B direction of Fig. 1;
Fig. 3 is a kind of structural representation of the plane filtering device that the embodiment of the present invention provides;
Fig. 4 is the frequency characteristic curve diagram of the plane filtering device that the embodiment of the present invention provides.
Embodiment
The invention provides a kind of plane filtering device, below in conjunction with accompanying drawing, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, do not limit the present invention.
The vertical view of the plane filtering device that Fig. 1 provides for embodiments of the invention, Fig. 2 is the cutaway view of device along A-B direction of Fig. 1, composition graphs 1 and Fig. 2, and embodiments of the invention provide a kind of plane filtering device, comprising:
The U-shaped resonant structure 1 be intervally installed, input transmission line 2 and output transmission line 3; The U-shaped bottom center of U-shaped resonant structure 1 is provided with earth point 10 to form the short dot of U-shaped resonant structure 1, and U-shaped resonant structure 1 is divided into the first resonant structure 11 and the second resonant structure 12 by earth point 10; The top of two U-shaped walls of U-shaped resonant structure 1 is separated from each other, to form the trip point of described U-shaped resonant structure;
Input transmission line 2 and output transmission line 3 are positioned at the outside of U-shaped resonant structure 1, wherein, input transmission line 2 extends along the first resonant structure 11, be coupled in U-shaped resonant structure 1 to make the signal in input transmission line 1 by the first resonant structure 11, export transmission line 3 to extend along the second resonant structure 12, to make described signal after resonance between the short dot and trip point of U-shaped resonant structure 1, be coupled to by the second resonant structure 12 and export in transmission line 3.
The plane filtering device that the embodiment of the present invention provides, the resonant structure 1 being used for carrying out signal filtering is designed to U-shaped, input transmission line 2 and output transmission line 3 are all close to this U-shaped resonant structure 1, compact conformation, the design of short dot and trip point can make signal form resonance in resonant structure 1, in certain frequency band range centered by resonance frequency, signal can be stored in U-shaped resonant structure 1 with the form of standing wave, thus the signal coupling in passband can be gone out by output transmission line 3, effectively achieve filtering with compact structure and lower cost and be convenient to antenna integrated.
Optionally, in the present embodiment, U-shaped resonant structure 1, input transmission line 2 and output transmission line 3 all can adopt microstrip line construction, and two-layer covering between copper presss from both sides dielectric 4, and earth point 10 is specifically connected with metal ground 5 by plated-through hole.
Specifically, signal is coupled to the process of U-shaped resonant structure 1 from input transport tape 2, there is a part of reflection loss, that is part energy does not enter in U-shaped resonant structure 1, but be reflected, in order to improve the utilance of signal energy, size and the interval of U-shaped resonant structure 1 and input transmission line 2 all need carefully to consider.Same reason, in order to make output transmission line 3 can more effectively by the signal coupling in U-shaped resonant structure 1 out, export transmission line 3 size and and the interval of U-shaped resonant structure 1 also need carefully to consider.Namely input transmission line 2, output transmission line 3 contain capacitive composition with being coupled between U-shaped resonant structure 1 and also contain sensitive ingredients, be equivalent to transmit in a series of distributed capacitor inductance network during the oscillation transmission of signal in U-shaped resonant structure 1, these electric capacity and inductance carry out filtering to signal.Specifically, can by controlling length ratio bottom the U-shaped arm of U-shaped resonant structure 1 and U-shaped and control inputs transmission line 2, the distance exported between the coupling unit distance trip point of transmission line 3 and U-shaped resonant structure 1 and short dot controls this capacitive coupling or inductive coupled of being coupled.Such as, in one embodiment of the invention, what input the U-shaped arm of transmission line 2 and the first resonant structure 11 is coupled as capacitive coupling, being coupled as bottom the U-shaped of input transmission line 2 and the first resonant structure 11 is inductive coupled, what export the U-shaped arm of transmission line 3 and the second resonant structure 12 is coupled as capacitive coupling, and being coupled as bottom the U-shaped of output transmission line 3 and the second resonant structure 12 is inductive coupled.
It should be noted that, originally the signal that U-shaped resonant structure 1 is coupled in U-shaped resonant structure 1 comprises multi-frequency, but repeatedly vibrate between short dot in U-shaped resonant structure 1 of the signal of these frequencies and trip point, can resonance be there is in the signal in last free transmission range centered by resonance frequency, standing wave is formed between short dot and trip point, the signal of other frequencies then can be attenuated gradually in repeatedly vibrating, thus realizes bandpass filtering.In order to optimize the frequency-selective filtering characteristic of U-shaped resonant structure 1 further, in one embodiment of the invention, the length of U-shaped resonant structure 1 can be the half of wavelength corresponding to the resonance frequency of filter.
Further, carrying out in the process of filtering to aerial signal, the frequency of aerial signal usually has certain change, and in order to carry out effective filtering to it, the resonance frequency of filter often also needs to adjust accordingly.In order to realize this goal, optionally, capacitor can be accessed between the top of two U-shaped arms, like this, when signal vibrates between U-shaped resonant structure trip point and trip point, signal can carry out feeding to a certain degree by the electric capacity between U-shaped arm top, thus makes the resonance frequency of whole U-shaped resonant structure 1 on original basis, have certain adjustment.Optionally, this capacitor both can be the capacitor of constant capacitance, and also can be the variable variable capacitor of capacitance, embodiments of the invention limit this.When this capacitor is variable capacitor, the adjustment that namely can be realized filter resonance frequency by the adjustment to variable capacitance capacitor.In order to obtain suitable resonance frequency, can select the capacitance range of variable capacitor as required, such as, in one embodiment of the invention, the capacitance of variable capacitor can between 0 to 0.5 pico farad.
It should be noted that, U-shaped resonant structure 1 becomes U-shaped on the whole, but becomes on the basis of U-shaped profile in entirety, can also adjust the local shape of U-shaped resonant structure 1.Such as, if need the distance from top of two U-shaped arms comparatively near, then can make the top inwardly bending relatively respectively of two U-shaped arms, to make these two tops at a distance of comparatively near, reach required separation distance.Or U-shaped resonant structure 1 can be axisymmetric, its symmetry axis can be through short dot and be parallel to the straight line of U-shaped arm.Accordingly, inputting transmission line 2 and export transmission line 3 also can be symmetrical about this symmetry axis.Like this, the input and output of plane filtering device, with regard to full symmetric, can exchange use.
Below by specific embodiment, plane filtering device provided by the invention is described in detail.Because this plane filtering device needs with antenna integrated, therefore the resonance frequency of filter generally should be covered as the conventional communication frequency of the wireless devices such as cell phone.Concrete, described plane filtering device can be the band pass filter means of 1920MHz to 1980MHz for free transmission range.
In order to realize the free transmission range of 1920MHz to 1980MHz, U-shaped resonant structure 1, input transmission line 2 and output transmission line 3 all adopt microstrip line construction, two-layer covering between copper presss from both sides F4B (copper foil clad plate of polytetrafluoroethylglass glass cloth) dielectric material, and the relative dielectric constant of F4B is ε
r=2.65, thickness is 0.8 millimeter.Remaining size characteristic can see the mark of Fig. 3, and unit is millimeter.As shown in Figure 3, in the present embodiment, U-shaped resonant structure 1 is axisymmetric, and its symmetry axis is through short dot and is parallel to the straight line of U-shaped arm.Input transmission line 2 and output transmission line 3 are also about this symmetry axis symmetry.Wherein, apart 0.28 millimeter, the U-shaped arm of input transmission line 2 and the first resonant structure 11, at a distance of 0.23 millimeter bottom the U-shaped of input transmission line 2 and the first resonant structure 11; Export the U-shaped arm of transmission line 3 and the second resonant structure 12 at a distance of 0.28 millimeter, at a distance of 0.23 millimeter bottom the U-shaped of output transmission line 3 and the second resonant structure 12; Input transmission line 2 with export transmission line 3 bottom U-shaped 0.25 millimeter apart.
When adding fixed capacitor C
0after=0.5pf, the resonance frequency of U-shaped resonant structure 1 has corresponding movement, and bandwidth also can respective change.Be shown in Fig. 4 and do not adding electric capacity and adding fixed capacity C
0when, the frequency characteristics of plane filtering device.Wherein, the solid line of series connection round dot is the filtering curve of U-shaped arm top plane filtering device when not adding capacitor, and the dotted line of series connection square is U-shaped arm top-loaded fixed capacitor C
0time plane filtering device filtering curve, and common solid line is that when U-shaped arm top-loaded capacitor, filter is not for the reflectivity of each frequency signal, and common dotted line is at U-shaped arm top-loaded fixed capacitor C
0time filter for the reflectivity of each frequency signal.
As seen from Figure 4, within the scope of 1920 ~ 1980MHz, when not adding capacitor, the reflection coefficient of filter is less than-12dB, and insertion loss is less than 1dB, is adding fixed capacitor C
0when, the reflection coefficient of filter is less than-12dB, and insertion loss is less than 1dB, and pass band width significantly reduces.And when the capacitor added is variable capacitor C
vtime, if the capacitance of this variable capacitor can change in 0 to 0.5pf scope, then the frequency characteristics of filter also just moves between solid line and dotted line in the diagram accordingly.
The plane filtering device that the present embodiment provides, not only structure is simply easy to processing, cost is low, and has that reflection coefficient is little, insertion loss is low, easily realize the advantages such as electric tuning filtering.
Although be example object, disclose the preferred embodiments of the present invention, it is also possible for those skilled in the art will recognize various improvement, increase and replacement, and therefore, scope of the present invention should be not limited to above-described embodiment.
Claims (10)
1. a plane filtering device, is characterized in that, comprising:
The U-shaped resonant structure be intervally installed, input transmission line and output transmission line;
The U-shaped bottom center of described U-shaped resonant structure is provided with earth point to form the short dot of described U-shaped resonant structure, and described U-shaped resonance portion is the first resonant structure and the second resonant structure by described earth point; The top of two U-shaped walls of described U-shaped resonant structure is separated from each other, to form the trip point of described U-shaped resonant structure;
Described input transmission line and described output transmission line are positioned at the outside of described U-shaped resonant structure, wherein, described input transmission line extends along described first resonant structure, be coupled in described U-shaped resonant structure to make the signal in described input transmission line by described first resonant structure, described output transmission line extends along described second resonant structure, to make described signal after resonance between the short dot and trip point of described U-shaped resonant structure, be coupled in described output transmission line by described second resonant structure.
2. device according to claim 1, is characterized in that, comprising: be provided with capacitor between the top of two U-shaped arms of described U-shaped resonant structure.
3. device according to claim 2, is characterized in that, described capacitor is fixed capacitor or variable capacitor.
4. device according to claim 3, is characterized in that, the capacitance of described capacitor is between 0 to 0.5 pico farad.
5. device according to claim 1, is characterized in that, the U-shaped arm of described input transmission line and described first resonant structure be coupled as capacitive coupling, being coupled as bottom the U-shaped of described input transmission line and described first resonant structure is inductive coupled; The U-shaped arm of described output transmission line and described second resonant structure be coupled as capacitive coupling, being coupled as bottom the U-shaped of described output transmission line and described second resonant structure is inductive coupled.
6. device according to claim 1, is characterized in that, described U-shaped resonant structure is axisymmetric, and its symmetry axis is through described short dot and is parallel to the straight line of described U-shaped arm.
7. device according to claim 6, is characterized in that, described input transmission line and described output transmission line are about described symmetry axis symmetry.
8. device according to claim 7, is characterized in that, apart 0.28 millimeter, the U-shaped arm of described input transmission line and described first resonant structure, at a distance of 0.23 millimeter bottom the U-shaped of described input transmission line and described first resonant structure; Described input transmission line and described output transmission line bottom described U-shaped 0.25 millimeter apart.
9. device according to any one of claim 1 to 8, is characterized in that, the length of described U-shaped resonant structure is the half of wavelength corresponding to the resonance frequency of described filter.
10. device according to any one of claim 1 to 8, is characterized in that, the band pass filter means of described plane filtering device to be free transmission range be 1920MHz to 1980MHz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410274118.3A CN105207639A (en) | 2014-06-19 | 2014-06-19 | Planar filter device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410274118.3A CN105207639A (en) | 2014-06-19 | 2014-06-19 | Planar filter device |
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| CN105207639A true CN105207639A (en) | 2015-12-30 |
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| CN201410274118.3A Pending CN105207639A (en) | 2014-06-19 | 2014-06-19 | Planar filter device |
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Citations (7)
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| CN1290052A (en) * | 1999-09-29 | 2001-04-04 | 株式会社东芝 | Flat filter and filter system |
| WO2006070036A1 (en) * | 2004-12-28 | 2006-07-06 | Universitat Autónoma De Barcelona | Planar filters for microwaves and millimetre waves, which contain open-loop resonators |
| WO2006070035A1 (en) * | 2004-12-28 | 2006-07-06 | Universitat Autonoma De Barcelona | Planar filters for microwaves and millimetre waves with a controllable bandwidth, which are based on concentrated resonators |
| CN202930514U (en) * | 2012-12-04 | 2013-05-08 | 哈尔滨飞羽科技有限公司 | U type impedance resonator-based mixed-path double-frequency microstrip coupling filter |
| CN103208974A (en) * | 2013-03-13 | 2013-07-17 | 南京航空航天大学 | Differential-mode and common-mode capacitance integration module for high-power plane electro-magnetic interference (EMI) filter |
| CN103779640A (en) * | 2014-01-16 | 2014-05-07 | 南京航空航天大学 | Micro-strip dual-passband filter |
| CN104577268A (en) * | 2015-01-04 | 2015-04-29 | 华南理工大学 | Planar lowpass-bandpass triplexer |
-
2014
- 2014-06-19 CN CN201410274118.3A patent/CN105207639A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1290052A (en) * | 1999-09-29 | 2001-04-04 | 株式会社东芝 | Flat filter and filter system |
| WO2006070036A1 (en) * | 2004-12-28 | 2006-07-06 | Universitat Autónoma De Barcelona | Planar filters for microwaves and millimetre waves, which contain open-loop resonators |
| WO2006070035A1 (en) * | 2004-12-28 | 2006-07-06 | Universitat Autonoma De Barcelona | Planar filters for microwaves and millimetre waves with a controllable bandwidth, which are based on concentrated resonators |
| CN202930514U (en) * | 2012-12-04 | 2013-05-08 | 哈尔滨飞羽科技有限公司 | U type impedance resonator-based mixed-path double-frequency microstrip coupling filter |
| CN103208974A (en) * | 2013-03-13 | 2013-07-17 | 南京航空航天大学 | Differential-mode and common-mode capacitance integration module for high-power plane electro-magnetic interference (EMI) filter |
| CN103779640A (en) * | 2014-01-16 | 2014-05-07 | 南京航空航天大学 | Micro-strip dual-passband filter |
| CN104577268A (en) * | 2015-01-04 | 2015-04-29 | 华南理工大学 | Planar lowpass-bandpass triplexer |
Non-Patent Citations (1)
| Title |
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| 范彦 等: "T型支节加载的双模双通带微带滤波器", 《现代电子技术》 * |
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Application publication date: 20151230 |