CN203871449U - Planar band pass filter based on concatenation of four resonators - Google Patents
Planar band pass filter based on concatenation of four resonators Download PDFInfo
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- CN203871449U CN203871449U CN201420243273.4U CN201420243273U CN203871449U CN 203871449 U CN203871449 U CN 203871449U CN 201420243273 U CN201420243273 U CN 201420243273U CN 203871449 U CN203871449 U CN 203871449U
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Abstract
The utility model discloses a planar band pass filter based on concatenation of four resonators. The planar band pass filter comprises an input feed line, an output feed line, a quarter wavelength first resonator, a quarter wavelength fourth resonator, a three-quarter wavelength second resonator and a three-quarter wavelength third resonator. The first resonator, the second resonator, the third resonator and the fourth resonator are successively cascaded to form an annular structure; the first resonator and the fourth resonator are respectively correspondingly parallel to the input feed line and the output feed line to respectively form a first coupling structure and a fifth coupling structure; the first resonator and the second resonator are connected with a first grounding through hole to form a second coupling structure; one end of the third resonator and one end of the fourth resonator are connected with a second grounding through hole to form a fourth coupling structure; a coupling gap exist between the second resonator and the third resonator so as to form a third coupling structure; and a coupling gap exists between the ports of the first resonator and the fourth resonator so as to form a sixth coupling structure. The planar band pass filter provided by the utility model has the advantages of high frequency selectivity and small in-band insertion loss.
Description
Technical field
The utility model relates to a kind of band pass filter, particularly a kind of plane bandpass filter based on four resonators of cascade.
Background technology
RF/Microwave filter is the requisite parts of system such as modern microwave trunking traffic, satellite communication, radio communication and electronic countermeasures, is also the most important and the highest microwave passive component of technology content simultaneously.Band pass filter is as one of part important in Circuits System, and the quality of its performance has largely determined the work quality of system.Band pass filter operates mainly in communication system radio-frequency front-end, for low-loss, by the useful signal in a certain frequency range, and the frequency component of other frequency ranges is decayed to extremely low-level.
Yet, along with the high speed development of modern communications demand, available frequency spectrum resource growing tension is therefore more and more higher to the requirement of filter frequencies selectivity characteristic.In order to improve message capacity and to avoid the interference between adjacent channel, require filter must have precipitous Out-of-band rejection; In order to improve signal to noise ratio, requiring will have low insertion loss in passband; And in order to reduce the distortion of signal, requiring has smooth amplitude-frequency characteristic and group delay characteristic in passband; In order to meet modern communications terminal trend toward miniaturization, require filter to have less volume and weight.Traditional Butterworth and Chebyshev filter have been difficult to meet these requirements, the filter of introducing the cross coupling structure with limited transmission zero be at present the most frequently used be also best selection.Compare with conventional filter, this filter not only can meet the high selectivity characteristic outside passband, can reduce the number of resonant cavity simultaneously, reduces design cost and filter volume.So far, had a lot of scholars to propose to have the microwave band-pass filter of cross coupling structure, wherein some shows good performance really: in-band insertion loss is less, selectivity is more high.Yet certain structures has but adopted too high exponent number to make filter volume excessive, is unfavorable for integrated.
Utility model content
The purpose of this utility model is to overcome the shortcoming of prior art with not enough, provide a kind of frequency selectivity higher, with the less plane bandpass filter based on four resonators of cascade of internal loss.The utility model has been introduced controlled cross-couplings between resonator, makes a plurality of transmission zeros of the outer generation of passband, thereby reach fast, roll-offs, and improves optionally object.
The purpose of this utility model is achieved through the following technical solutions: a kind of plane bandpass filter based on four resonators of cascade, comprises incoming feeder and output feeder; Described filter also comprises structure is identical and position is symmetrical quarter-wave the first resonator and the 4th resonator and structure is identical and position is symmetrical four/three-wavelength the second resonator and the 3rd resonator; Described the first resonator, the second resonator, the 3rd resonator and the 4th resonator successively cascade form a loop configuration;
Described the first resonator is corresponding parallel one by one with output feeder with incoming feeder respectively with the 4th resonator; And between described the first resonator and incoming feeder, there is gap, form the first coupled structure;
One end of described first resonator one end and the second resonator is connected the first grounding through hole, and described the first grounding through hole is to introduce magnetic coupling between the first resonator and the second resonator, forms the second coupled structure;
Between described the second resonator and the 3rd resonator, there is coupling gap, form the 3rd coupled structure;
One end of described the 3rd resonator one end and the 4th resonator is connected with the second grounding through hole; Described the second grounding through hole is to introduce magnetic coupling between the 3rd resonator and the 4th resonator, forms the 4th coupled structure;
Between described the 4th resonator and output feeder, there is gap, form the 5th coupled structure;
Between described the first resonator and the 4th resonator port, there is coupling gap, form the 6th coupled structure.
Preferably, described the first resonator and the 4th resonator are a microstrip line, one of them port as the microstrip line of the first resonator and microstrip line as the 4th resonator is connected with the second grounding through hole with the first grounding through hole respectively, article two, between another port of microstrip line, there is a gap, form described the 6th coupled structure; Wherein two microstrip lines are symmetrical arranged and on same straight line.
Preferably, described the second resonator forms by the first microstrip line being connected successively, the second microstrip line, the 3rd microstrip line, the 4th microstrip line, the 5th microstrip line and the 6th microstrip line with the 3rd resonator, and wherein the angle between above-mentioned interconnected microstrip line is 90 degree;
Described the second resonator is connected with the second grounding through hole is corresponding with the first grounding through hole respectively by the first microstrip line with the 3rd resonator, between described the second resonator and the 3rd resonator, exist a coupling gap to be between the second resonator and the 3rd resonator the 5th microstrip line and have coupling gap, formed described the 3rd coupled structure.
Further, angle between described the first resonator and the first microstrip line of the second resonator is 90 degree, between the second microstrip line of described the second resonator and the first resonator, there is coupling gap, form described the second coupled structure together with the first grounding through hole;
Angle between described the 4th resonator and the first microstrip line of the 3rd resonator is 90 degree, between the second microstrip line of described the 3rd resonator and the 4th resonator, has coupling gap, forms described the 4th coupled structure together with the second grounding through hole;
The width of the coupling gap between the coupling gap between described the second resonator and the first resonator and the 3rd resonator and the 4th resonator is the length of the first microstrip line of the second resonator and the 3rd resonator.
Preferably, between described the second resonator and the 3rd resonator, the original position of coupling gap is: from the second resonator and the 3rd resonator short-circuit end, start at 2/3rds of the second resonator and the 3rd resonator total length.
Preferably, described incoming feeder is connected by the 7th microstrip line being connected successively, the 8th microstrip line and the 9th microstrip line with output feeder; Described electromagnetic wave, from the 7th microstrip line feed-in of incoming feeder, feeds out from the 7th microstrip line of output feeder; Described the 7th microstrip line, the 8th microstrip line and the 9th microstrip line connect into " 7 " type structure, between the 7th microstrip line and the 8th microstrip line, form an obtuse angle, between the 8th microstrip line and the 9th microstrip line, form an acute angle;
Wherein incoming feeder and output feeder are symmetrical arranged, and the 9th microstrip line of incoming feeder is parallel with the first resonator, and the 9th microstrip line of output feeder is parallel with the 4th resonator.
Preferably, between the port of described incoming feeder the 9th microstrip line and the port of output feeder the 9th microstrip line, there is a coupling gap, form described the 7th coupled structure.
Preferably, the input port of described incoming feeder and the output port of output feeder are the matched impedance of 50 ohm.
Preferably, described plane bandpass filter is produced on the micro-belt substrate of double-sided copper-clad in the mode of printed circuit board (PCB), and wherein the other one side of micro-belt substrate is to cover copper ground plate.
The utility model has following advantage and effect with respect to prior art:
(1) flat filter of the present utility model is become with two four/three-wavelength resonator stages joint groups by two quarter-wave resonance devices, has advantages of that volume is little easily integrated.Between incoming feeder and output feeder and the first resonator and the 4th resonator, form respectively coupled structure in addition, between resonator, also form respectively coupled structure, by adjusting magnetic coupling and the electric coupling intensity between resonator and between resonator and incoming feeder and output feeder, make the bandwidth of filter adjusted within the specific limits, thereby can control easily the bandwidth of filter.In the present invention by introduced controlled cross-couplings between the first resonator and the 4th resonator, thereby make the passband both sides of filter of the present invention produce a plurality of transmission zeros, greatly improved the Out-of-band rejection effect of filter, greatly improved the frequency selective characteristic of filter of the present invention, had advantages of that in-band insertion loss is little simultaneously.
(2) flat filter of the present utility model also by introducing cross-couplings between incoming feeder and output feeder, thereby make the passband both sides of filter produce more many transmission zeros, further mentioned the frequency selective characteristic of the utility model filter.
(3) what flat filter of the present utility model adopted is micro-band forms, therefore has advantages of flexible design, cost is low, volume is little and be convenient to integrated.
Accompanying drawing explanation
Fig. 1 is the structural representation of the utility model plane bandpass filter.
Fig. 2 is insertion loss and the return loss of the utility model plane bandpass filter in 1.2GHz arrives 4.8GHz frequency range.
Fig. 3 is insertion loss and the return loss of the utility model plane bandpass filter in 1GHz arrives 10GHz frequency range.
Embodiment
Below in conjunction with embodiment and accompanying drawing, the utility model is described in further detail, but execution mode of the present utility model is not limited to this.
Embodiment
As shown in Figure 1, the present embodiment discloses a kind of plane bandpass filter based on four resonators of cascade, wherein the plane bandpass filter of the present embodiment is produced on the micro-belt substrate 1 of double-sided copper-clad in the mode of printed circuit board (PCB), the other one side of micro-belt substrate 1 is to cover copper ground plate, the relative dielectric constant of this micro-belt substrate is 2.55, and medium height is 0.80mm.
The present embodiment plane bandpass filter comprises structure is identical and position is symmetrical incoming feeder 2 and output feeder 3, structure is identical and position is symmetrical quarter-wave the first resonator 4 and the 4th resonator 5 and structure is identical and position is symmetrical four/three-wavelength the second resonator 6 and the 3rd resonator 7; Wherein the first resonator 4, the second resonator 6, the 3rd resonator 7 and the 4th resonator 5 successively cascade form a loop configuration;
In the present embodiment, incoming feeder 2 is connected by the 7th microstrip line being connected successively, the 8th microstrip line and the 9th microstrip line with output feeder 3; Described electromagnetic wave signal is from the port1 port feed-in of the 7th microstrip line of incoming feeder, from the port2 port of the 7th microstrip line of output feeder 3, feeds out the useful signal of the particular frequency range after filter is selected; Described the 7th microstrip line, the 8th microstrip line and the 9th microstrip line connect into " 7 " type structure, between the 7th microstrip line and the 8th microstrip line, form an obtuse angle, between the 8th microstrip line and the 9th microstrip line, form an acute angle.The 9th microstrip line of incoming feeder and output feeder is symmetrical arranged and on same straight line.The width W of the 9th microstrip line of incoming feeder 2 and output feeder 3 wherein
2=1.1mm.In three feeder lines of incoming feeder and output feeder, the width of the 7th microstrip line, the 8th microstrip line and the 9th microstrip line reduces successively.The input port 2 of incoming feeder and the output port of output feeder 3 are the matched impedance of 50 ohm.
In the present embodiment, the first resonator 4 consists of microstrip line, and the 4th resonator 5 consists of microstrip line, and wherein two microstrip lines are symmetrical arranged and on same straight line.Article two, the length L of microstrip line
1=16.9mm.
In the present embodiment, the second resonator 6 forms by the first microstrip line being connected successively, the second microstrip line, the 3rd microstrip line, the 4th microstrip line, the 5th microstrip line and the 6th microstrip line with the 3rd resonator 7, and wherein the angle between above-mentioned interconnected microstrip line is 90 degree; As shown in fig. 1, the second resonator 6 and the 3rd resonator 7 of six microstrip line formations are similar to helical structure.Wherein the first microstrip line of two resonators is parallel to each other, and the second microstrip line is on same straight line, and the 3rd microstrip line is parallel to each other, and the 4th microstrip line is on same straight line, and the 5th microstrip line is parallel to each other, and the 6th microstrip line is on same straight line.The second microstrip line length L
2=4.9mm, the 3rd microstrip line length L
3=16.0mm, the 4th microstrip line length L
4=11.0mm, the 5th microstrip line length L
5=11.0mm, the 6th microstrip line length L
6=9.3mm.The width of above-mentioned each microstrip line is W
1=1.0mm.
The 9th microstrip line of the present embodiment incoming feeder 2 is parallel with the microstrip line of the first resonator 4, and has gap 14 between the first resonator 4 and incoming feeder 2, forms the first coupled structure; By adjusting the size in this gap 14, can adjust the stiffness of coupling between the first resonance filter 4 and incoming feeder 2.
The first microstrip line of the microstrip line of the present embodiment the first resonator 4 and the second resonator 6 is connected with the first grounding through hole 8 respectively, and the angle between the first microstrip line of the microstrip line of the first resonator 4 and the second resonator 6 is 90 degree, by the first grounding through hole 8, introduce magnetic coupling, the second microstrip line of other the second resonator 6 is parallel with the microstrip line of the first resonator 4 and form a gap 10, by this gap 10 and the first grounding through hole 8, form the second coupled structure, the present embodiment can be adjusted the stiffness of coupling between the first resonator 4 and the second resonator 6 by adjusting the size in this gap 10 or the size of the first grounding through hole 8.
Between the present embodiment the second resonator 6 and the 5th microstrip line of the 3rd resonator 7, there is gap 11, form the 3rd coupled structure, by adjusting this gap 11, regulate the stiffness of coupling between the second resonator 6 and the 3rd resonator 7.Wherein the original position in this gap 11 is: from the second resonator 6 and the 3rd resonator 7 short-circuit ends, start at 2/3rds of the second resonator 6 and the 3rd resonator 7 total lengths.
The first microstrip line of the present embodiment the 3rd resonator 7 is connected with equal the second grounding through hole 9 of the microstrip line of the 4th resonator 5, by the second grounding through hole 9, introduce magnetic coupling, the second microstrip line of other the 3rd resonator is parallel with the microstrip line of the 4th resonator and form a gap 12, by this gap 12 and the second grounding through hole 9, form the 4th coupled structure, the present embodiment can be adjusted the stiffness of coupling between the 3rd resonator and the 4th resonator by adjusting the size in this gap 12 or the size of the second grounding through hole 9.
The 9th microstrip line of the present embodiment output feeder 3 is parallel with the microstrip line of the 4th resonator 5, and has gap 15 between the microstrip line of the 4th resonator 5 and output feeder 3, forms the 5th coupled structure; By adjusting the size in this gap 12, can adjust the stiffness of coupling between the 4th resonance filter 5 and output feeder 3.
The gap 13, one of one end that one end that the microstrip line of the present embodiment the first resonator 4 is not connected with the first grounding through hole 8 and the microstrip line of the 4th resonator 5 are not connected with the second grounding through hole 9, form the 6th coupled structure, by this coupled structure for introducing controlled cross-couplings between the first resonator 4 and the 4th resonator 5, in the present embodiment, this cross-couplings makes plane bandpass filter passband both sides produce 2 transmission zeros, by the size of adjusting play 13, can adjust the cross-couplings intensity between the first resonator 4 and the 4th resonator 5 in addition.
Between the port of the 9th microstrip line of the present embodiment incoming feeder 2 and output feeder 3, form a gap, form the 7th coupled structure, by the 7th coupled structure, between the feeder line of source load end, introduce cross-couplings, in the present embodiment, this cross-couplings makes plane bandpass filter passband both sides produce 4 transmission zeros, can adjust the cross-couplings intensity between incoming feeder 2 and output feeder 3 in addition by adjusting the size in this gap.
Wherein the scattering parameter simulation result of the present embodiment plane bandpass filter as shown in Figure 2, wherein frequency range is that 1.2GHz is to 4.8GHz, transverse axis represents the frequency input signal of the present embodiment band pass filter, the longitudinal axis represents logarithm amplitude (dB), comprises the amplitude of insertion loss S21 and the amplitude of return loss S11.Wherein S21 represents that its corresponding mathematical function is by the signal input power of the present embodiment band pass filter and the relation between output power signal:
10*lg(Pi/Po)(dB)＝20*lg|S21|；
Wherein Pi represents input power, and Po represents power output.
In the signals transmission of the present embodiment band pass filter, the Partial Power of signal is reflected back toward signal source, and the power being reflected becomes reflection power; Wherein S11 represents the input power of signal of the present embodiment band pass filter and the relation between the reflection power of signal, and its corresponding mathematical function is:
10*lg(Pr/Pi)(dB)＝20*lg|S11|；
Wherein Pr represents reflection power, and Pi represents input power.
The present embodiment filter center frequency is 3GHz, according to drawing in the curve of return loss S11 in Fig. 2, in passband, there are four reflection zeros clearly, wherein in-band insertion loss absolute value is less than 1.5dB, and return loss absolute value is greater than 20dB, and produces six transmission zeros in passband both sides, effectively increased the steepness of cut-off frequency, stopband is declined fast, band edge is more precipitous, has greatly improved the frequency selective characteristic of filter.
As shown in Figure 3, frequency range is that 1GHz is during to 10GHz, the scattering parameter simulation result of the present embodiment plane bandpass filter, in figure, can draw, the present embodiment plane bandpass filter can produce a plurality of transmission zero point in passband both sides ,-20dB Out-of-band rejection starts to 8.92GHz from 3.22GHz, and the parasitic passband of two frequencys multiplication is inhibited, visible, very good of Out-of-band rejection characteristic.
Above-described embodiment is preferably execution mode of the utility model; but execution mode of the present utility model is not restricted to the described embodiments; other any do not deviate from change, the modification done under Spirit Essence of the present utility model and principle, substitutes, combination, simplify; all should be equivalent substitute mode, within being included in protection range of the present utility model.
Claims (9)
1. the plane bandpass filter based on four resonators of cascade, comprises incoming feeder and output feeder; It is characterized in that, described filter also comprises structure is identical and position is symmetrical quarter-wave the first resonator and the 4th resonator and structure is identical and position is symmetrical four/three-wavelength the second resonator and the 3rd resonator; Described the first resonator, the second resonator, the 3rd resonator and the 4th resonator successively cascade form a loop configuration;
Described the first resonator is parallel with incoming feeder, and has gap between described the first resonator and incoming feeder, forms the first coupled structure;
One end of described first resonator one end and the second resonator is connected the first grounding through hole, and described the first grounding through hole is to introduce magnetic coupling between the first resonator and the second resonator, forms the second coupled structure;
Between described the second resonator and the 3rd resonator, there is coupling gap, form the 3rd coupled structure;
One end of described the 3rd resonator one end and the 4th resonator is connected with the second grounding through hole; Described the second grounding through hole is to introduce magnetic coupling between the 3rd resonator and the 4th resonator, forms the 4th coupled structure;
Described the 4th resonator is parallel with output feeder, and has gap between described the 4th resonator and output feeder, forms the 5th coupled structure;
Between described the first resonator and the 4th resonator port, there is coupling gap, form the 6th coupled structure.
2. the plane bandpass filter based on four resonators of cascade according to claim 1, it is characterized in that, described the first resonator and the 4th resonator are a microstrip line, one of them port as the microstrip line of the first resonator and microstrip line as the 4th resonator is connected with the second grounding through hole with the first grounding through hole respectively, article two, between another port of microstrip line, there is a gap, form described the 6th coupled structure; Wherein two microstrip lines are symmetrical arranged and on same straight line.
3. the plane bandpass filter based on four resonators of cascade according to claim 1, it is characterized in that, described the second resonator forms by the first microstrip line being connected successively, the second microstrip line, the 3rd microstrip line, the 4th microstrip line, the 5th microstrip line and the 6th microstrip line with the 3rd resonator, and wherein the angle between above-mentioned interconnected microstrip line is 90 degree;
Described the second resonator is connected with the second grounding through hole is corresponding with the first grounding through hole respectively by the first microstrip line with the 3rd resonator, between described the second resonator and the 3rd resonator, exist a coupling gap to be between the second resonator and the 3rd resonator the 5th microstrip line and have coupling gap, formed described the 3rd coupled structure.
4. the plane bandpass filter based on four resonators of cascade according to claim 3, it is characterized in that, angle between described the first resonator and the first microstrip line of the second resonator is 90 degree, between the second microstrip line of described the second resonator and the first resonator, there is coupling gap, form described the second coupled structure together with the first grounding through hole;
Angle between described the 4th resonator and the first microstrip line of the 3rd resonator is 90 degree, between the second microstrip line of described the 3rd resonator and the 4th resonator, has coupling gap, forms described the 4th coupled structure together with the second grounding through hole;
The width of the coupling gap between the coupling gap between described the second resonator and the first resonator and the 3rd resonator and the 4th resonator is the length of the first microstrip line of the second resonator and the 3rd resonator.
5. the plane bandpass filter based on four resonators of cascade according to claim 1, it is characterized in that, between described the second resonator and the 3rd resonator, the original position of coupling gap is: from the second resonator and the 3rd resonator short-circuit end, start at 2/3rds of the second resonator and the 3rd resonator total length.
6. the plane bandpass filter based on four resonators of cascade according to claim 1, is characterized in that, described incoming feeder is connected by the 7th microstrip line being connected successively, the 8th microstrip line and the 9th microstrip line with output feeder; Described electromagnetic wave, from the 7th microstrip line feed-in of incoming feeder, feeds out from the 7th microstrip line of output feeder; Described the 7th microstrip line, the 8th microstrip line and the 9th microstrip line connect into " 7 " type structure, between the 7th microstrip line and the 8th microstrip line, form an obtuse angle, between the 8th microstrip line and the 9th microstrip line, form an acute angle;
Wherein incoming feeder and output feeder are symmetrical arranged, and the 9th microstrip line of incoming feeder is parallel with the first resonator, and the 9th microstrip line of output feeder is parallel with the 4th resonator.
7. the plane bandpass filter based on four resonators of cascade according to claim 6, it is characterized in that, between the port of the port of described incoming feeder the 9th microstrip line and output feeder the 9th microstrip line, there is a coupling gap, form the 7th coupled structure.
8. the plane bandpass filter based on four resonators of cascade according to claim 1, is characterized in that, the input port of described incoming feeder and the output port of output feeder are the matched impedance of 50 ohm.
9. the plane bandpass filter based on four resonators of cascade according to claim 1, it is characterized in that, described plane bandpass filter is produced on the micro-belt substrate of double-sided copper-clad in the mode of printed circuit board (PCB), and wherein the other one side of micro-belt substrate is to cover copper ground plate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201420243273.4U CN203871449U (en) | 2014-05-12 | 2014-05-12 | Planar band pass filter based on concatenation of four resonators |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420243273.4U CN203871449U (en) | 2014-05-12 | 2014-05-12 | Planar band pass filter based on concatenation of four resonators |
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| CN203871449U true CN203871449U (en) | 2014-10-08 |
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| CN201420243273.4U Withdrawn - After Issue CN203871449U (en) | 2014-05-12 | 2014-05-12 | Planar band pass filter based on concatenation of four resonators |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104009271A (en) * | 2014-05-12 | 2014-08-27 | 华南理工大学 | Plane band-pass filter on the basis of four cascaded resonators |
-
2014
- 2014-05-12 CN CN201420243273.4U patent/CN203871449U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104009271A (en) * | 2014-05-12 | 2014-08-27 | 华南理工大学 | Plane band-pass filter on the basis of four cascaded resonators |
| CN104009271B (en) * | 2014-05-12 | 2016-04-13 | 华南理工大学 | A kind of plane bandpass filter based on cascade four resonators |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20141008 Effective date of abandoning: 20160413 |
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| C25 | Abandonment of patent right or utility model to avoid double patenting |