CN102255125A - Novel double-frequency narrow-band bandpass filter - Google Patents
Novel double-frequency narrow-band bandpass filter Download PDFInfo
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- CN102255125A CN102255125A CN201110107737XA CN201110107737A CN102255125A CN 102255125 A CN102255125 A CN 102255125A CN 201110107737X A CN201110107737X A CN 201110107737XA CN 201110107737 A CN201110107737 A CN 201110107737A CN 102255125 A CN102255125 A CN 102255125A
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Abstract
The invention relates to a novel double-frequency narrow-band bandpass filter. The novel double-frequency narrow-band bandpass filter comprises a metal microstrip line on the front surface, a medium plate layer, an input port and an output port on the middle part, and a metal plating layer on the rear side of a medium plate, wherein in the metal microstrip line, a resonator consisting of a section of low impedance line and a stepped impedance line connected with the low impedance line, and a novel resonator formed by connecting a quarter wavelength uniform impedance line and a feeder with a rectangular short microstrip line. The resonator structure is symmetrical, so that an odd-even mode theory can be used for analyzing the resonator structure; and the input port and the output port of the feeder are in the same level line. A transmission zero is inserted into a stop band between two pass bands, a zero position in a transmission characteristic curve can be flexibly adjusted, the stop band characteristics are improved, and a transmission zero is inserted outside two center frequencies respectively to improve out-of-band rejection characteristics. The novel double-frequency narrow-band bandpass filter has a simple structure and extremely high frequency selectivity and meets the requirements on miniaturization.
Description
Technical field
The present invention relates to a kind of novel double frequency narrow band filter, belong to the double frequency band-pass filter category that has transmission zero in the wireless communication technology field.
Background technology
Along with developing rapidly of the communication technology, particularly development of wireless communication devices, more and more higher to the requirement of wireless communication system median filter.U.S.'s Institute of Electrical and Electronics Engineers in 1997 (being called for short IEEE) has been formulated 802.11 WLAN (Wireless Local Area Network) agreement, for one section new milestone has been opened in the radio communication development.
Traditional filter can not satisfy the needs of wireless communication system, and frequency spectrum resource is rare now, people but are more and more urgent to the demand of the big volume transport of information, so adopt double frequency or multiband filter can well satisfy the demand of wireless communication system.Traditional design is to be to add a plurality of filters in communication system, has so not only increased cost, and can take bigger system space.So in a device, realize double frequency or multifrequency, and realize that miniaturization Design is the trend of filter development.
Summary of the invention
The objective of the invention is to defective at the prior art existence, a kind of novel double frequency narrow band filter based on low-impedance line and parallel coupled line is provided, make its band internal loss low, the outer transmission zero that adds of band, and good harmonic wave suppression characteristic is arranged, realized simultaneously simplifying the structure, and then realized the miniaturization of filter.
For achieving the above object, design of the present invention is:
1. on the basis of traditional parallel coupled line,, form the step electric impedance resonator, realized new coupling, can change the position of transmission zero by the length that changes short impedance line by between two parallel coupled lines, adding short impedance line.
2. on the basis of traditional uniform impedance resonator (UIR) structure, add short microstrip line, realized fine harmonic wave suppression characteristic, reduced the insertion loss of spurious frequency by the corner that links to each other with feeder line at resonator.
3. the present invention adopts following dielectric-slab material: medium substrate selects for use dielectric constant to be
=10.2, thickness
h=0.635mm.Adopt low-impedance line and parallel coupled line structure.
4. the circuit board after the processing is divided into three layers, and promptly the front is the metal micro-strip line structure, and the centre is medium flaggy and input/output port, and the medium sheet material back side is layer of metal coating, and wherein welding two sub-miniature A connectors in input/output port place are used for actual measurement.The front metal microstrip line construction is by a low-impedance line, and novel parallel coupling line, and novel resonator composition can be regulated the position at zero point and the broadband of frequency band by the distance that changes two parallel coupled lines.
According to the foregoing invention design, the present invention adopts following technical proposals:
A kind of novel double frequency narrow band filter, comprise three-decker: the coat of metal of the medium flaggy of positive metal micro-strip line, centre and input/output port, medium sheet material reverse side, described metal micro-strip line structure is: the resonator that constitutes by one section low-impedance line and the step impedance line that is attached thereto, and is connected rectangle with feeder line by quarter-wave uniform impedance line and lacks the novel resonator that microstrip line constitutes; Because resonator structure is symmetrical, so available even odd mode theory is analyzed; The input/output port of its feeder line is on same horizontal line.
Described step impedance line is to be made of short impedance line of the terminal connection of two parallel coupled lines, has realized new coupling.
Described rectangular microstrip line is positioned at the described quarter-wave uniform impedance line corner that links to each other with feeder line, has realized fine harmonic wave suppression characteristic.
Described medium flaggy is a dielectric constant
=10.2 dielectric-slab, this dielectric-slab thickness
h=0.635mm.
The coat of metal of described metal micro-strip line and reverse side part can be an electric conductivity preferred metal material, as gold or silver or copper.
The dielectric constant of the dielectric-slab in described intermediate layer can be various numerical value, because square being inversely proportional to of the length of dielectric constant and resonator, so the size of the high more then respective filter of dielectric constant is more little.
The present invention has following conspicuous outstanding substantive distinguishing features and remarkable advantage compared with prior art:
Description of drawings
Fig. 1 is traditional step electric impedance resonator (SIR) cellular construction figure.
Fig. 2 is the cellular construction schematic diagram that improved low-impedance line and parallel coupled line are formed.
Fig. 3 is traditional feeder line and resonator structure schematic diagram.
Fig. 4 improves back feeder line and resonator structure schematic diagram.
Fig. 5 is the double band bandpass filter microstrip line construction schematic diagram of traditional structure.
Fig. 6 is the novel double frequency narrow band filter of a present invention overall structure schematic diagram.
Fig. 7 is the frequency response schematic diagram of the double frequency filter of traditional structure realization.
Fig. 8 is the frequency response schematic diagram of the novel double frequency narrow band filter of the present invention emulation.
Embodiment
Below in conjunction with accompanying drawing a preferred embodiment of the present invention is elaborated:
The cellular construction schematic diagram that improved low-impedance line proposed by the invention and parallel coupled line are formed as shown in Figure 2, it is on the basis of traditional step electric impedance resonator (SIR) cellular construction Fig. 1 the high impedance line to be divided into two parallel coupled lines, has changed coupled characteristic.Can change the position of the transmission zero between two passbands by the distance that changes parallel coupled line.
As shown in Figure 3, being traditional feeder line and resonator structure schematic diagram, is the mode that adopts direct feed, and Fig. 4 is for improving the structural representation of back feeder line and resonator, and the short microstrip line of corner's adding at feeder line and resonator has strengthened the harmonic wave suppression characteristic.
Embodiment one: referring to Fig. 6, the double frequency-band narrow band filter that this is novel, comprise three-decker: the coat of metal of the medium flaggy of positive metal micro-strip line, centre and input/output port, medium sheet material reverse side, described metal micro-strip line structure is: the resonator that constitutes by one section low-impedance line and the step impedance line that is attached thereto, and is connected rectangle with feeder line by quarter-wave uniform impedance line and lacks the novel resonator that microstrip line constitutes; Because resonator structure is symmetrical, so available even odd mode theory is analyzed; The input/output port of its feeder line is on same horizontal line.
Embodiment two: present embodiment and embodiment one are basic identical, and special feature is: described step impedance line is to be made of the terminal short impedance line (11) that connects of two parallel coupled lines (7), has realized new coupling.The short microstrip line of described rectangle (9) is positioned at described quarter-wave uniform impedance line (8) corner that links to each other with feeder line (12), has realized fine harmonic wave suppression characteristic.Described medium flaggy (5) is a dielectric constant
=10.2 dielectric-slab, this dielectric-slab thickness
h=0.635mm.
Embodiment three: present embodiment and embodiment two are basic identical, and special feature is: Fig. 6 is the structural representation of present embodiment, through design, emulation and optimization, determines that finally the concrete size of the super narrow band filter of this little band is as follows:
L1=7.3mm，?L2=10.0mm，L3=8.4mm，L4=0.8mm
W1=6.0mm, W2=0.6mm, W3=0.6mm,?W4=1.1mm
G=0.2mm， D=0.2mm，
Having designed centre frequency based on said method is 2.62GHz/5.98GHz, and relative bandwidth is about 6% microstrip filter, and Sonnet carries out emulation by Electromagnetic Simulation software, debugging.
Fig. 7 has shown the frequency response simulation result of the double frequency filter that traditional structure is realized.
Fig. 8 has shown the simulation architecture of this microstrip filter, and no matter simulation result is that band internal characteristic or band are outer if showing suppresses, and the present invention has good superiority.Compare with Fig. 7 simultaneously and reduced centre frequency, be with outer steepness obvious.And Filter Structures is simple, and size is little, has realized miniaturization.
Above simulation result shows:
(1) pass band width is about 120MHz, and in-band insertion loss is all less than 0.1dB;
(2) passband is precipitous by the edge, has dropped to when 1.06GHz-80dB, has inserted transmission zero at 4.66GHz and 6.8GHz place;
In having realized band, band is outer well behaved, and microstrip structure is simple simultaneously, and size also obtains miniaturization, prints simple and easyly, and spillage of material is less relatively.
Claims (4)
1. novel double frequency narrow band filter, comprise three-decker: the coat of metal (2) of the medium flaggy (5) of positive metal micro-strip line (1), centre and input/output port (4,10), medium sheet material reverse side, it is characterized in that described metal micro-strip line (1) structure is: the resonator that constitutes by one section low-impedance line (6) and the step impedance line that is attached thereto, and is connected the novel resonator that rectangle is lacked microstrip line (9) formation with feeder line (12) by quarter-wave uniform impedance line (8); Because resonator structure is symmetrical, so available even odd mode theory is analyzed; The input/output port of its feeder line (12) (4,10) is on same horizontal line.
2. a kind of novel double frequency narrow band filter according to claim 1 is characterized in that described step impedance line is to be made of the terminal short impedance line (11) that connects of two parallel coupled lines (7), has realized new coupling.
3. a kind of novel double frequency narrow band filter according to claim 1, it is characterized in that the short microstrip line of described rectangle (9) is positioned at described quarter-wave uniform impedance line (8) corner that links to each other with feeder line (12), has realized fine harmonic wave suppression characteristic.
4. a kind of novel double frequency narrow band filter according to claim 1 is characterized in that described medium flaggy (5) is a dielectric constant
=10.2 dielectric-slab, this dielectric-slab thickness
h=0.635mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110107737.XA CN102255125B (en) | 2010-09-21 | 2011-04-28 | Novel double-frequency narrow-band bandpass filter |
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| CN201010289991 | 2010-09-21 | ||
| CN201010289991.1 | 2010-09-21 | ||
| CN201110107737.XA CN102255125B (en) | 2010-09-21 | 2011-04-28 | Novel double-frequency narrow-band bandpass filter |
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| CN102255125A true CN102255125A (en) | 2011-11-23 |
| CN102255125B CN102255125B (en) | 2014-10-01 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105742769A (en) * | 2016-02-25 | 2016-07-06 | 南京邮电大学 | Harmonic suppression adjustable planar dual-mode T-shaped bandpass filter |
| CN106169635A (en) * | 2016-08-13 | 2016-11-30 | 南京理工大学 | A kind of pocket super-broadband band filter with trap characteristic |
| CN109638398A (en) * | 2018-12-21 | 2019-04-16 | 南京邮电大学 | With Wide stop bands and highly selective compact bandpass filter |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN200972896Y (en) * | 2006-10-26 | 2007-11-07 | 浙江大学 | Microstrip antenna |
| CN101515661A (en) * | 2009-03-26 | 2009-08-26 | 上海大学 | Microstrip dual-mode filter of nesting ring-structured parallel feeder lines |
| CN201528031U (en) * | 2009-08-26 | 2010-07-14 | 东南大学 | L-type coupled-structure dual-mode microstrip bandpass filter |
-
2011
- 2011-04-28 CN CN201110107737.XA patent/CN102255125B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN200972896Y (en) * | 2006-10-26 | 2007-11-07 | 浙江大学 | Microstrip antenna |
| CN101515661A (en) * | 2009-03-26 | 2009-08-26 | 上海大学 | Microstrip dual-mode filter of nesting ring-structured parallel feeder lines |
| CN201528031U (en) * | 2009-08-26 | 2010-07-14 | 东南大学 | L-type coupled-structure dual-mode microstrip bandpass filter |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105742769A (en) * | 2016-02-25 | 2016-07-06 | 南京邮电大学 | Harmonic suppression adjustable planar dual-mode T-shaped bandpass filter |
| CN105742769B (en) * | 2016-02-25 | 2018-03-09 | 南京邮电大学 | The adjustable plane bimodulus T-shaped bandpass filter of harmonics restraint |
| CN106169635A (en) * | 2016-08-13 | 2016-11-30 | 南京理工大学 | A kind of pocket super-broadband band filter with trap characteristic |
| CN106169635B (en) * | 2016-08-13 | 2018-10-12 | 南京理工大学 | A kind of pocket super-broadband bandpass filter with trap characteristic |
| CN109638398A (en) * | 2018-12-21 | 2019-04-16 | 南京邮电大学 | With Wide stop bands and highly selective compact bandpass filter |
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| Publication number | Publication date |
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| CN102255125B (en) | 2014-10-01 |
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