CN104393378A - Continuously adjustable band pass filter based on nematic liquid crystals - Google Patents
Continuously adjustable band pass filter based on nematic liquid crystals Download PDFInfo
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- CN104393378A CN104393378A CN201410680583.7A CN201410680583A CN104393378A CN 104393378 A CN104393378 A CN 104393378A CN 201410680583 A CN201410680583 A CN 201410680583A CN 104393378 A CN104393378 A CN 104393378A
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Abstract
The invention discloses a continuously adjustable band pass filter based on nematic liquid crystals. The continuously adjustable band pass filter mainly comprises a top-layer dielectric slab, a bottom-layer dielectric slab, a metal plate and the liquid crystals. The top-layer dielectric slab is rectangular and is a printed circuit board mainly used for carrying a filter resonance unit and input and output feeders; extremely thin metal layers are formed on the upper and lower surfaces of the top-layer dielectric slab and connected by use of metallized holes. The bottom-layer dielectric slab is rectangular and the middle region of the bottom-layer dielectric slab is hollowed-out to form a rectangular hole groove. The metal plate is attached under the back of the bottom-layer printed dielectric slab and is a rectangular metal sheet for carrying the printed circuit board and the nematic liquid crystal material, and the metal plate is earthed. The perforated dielectric slab and the metal plate are combined to form a rectangular groove for holding the liquid crystals. The continuously adjustable band pass filter based on the nematic liquid crystals is of a planar structure, and is compact in structure, convenient to integrate and convenient to minimize; the filter is capable of working in a continuously adjustable state, and is relatively low in insertion loss, and low in cost due to the adoption of the common printed circuit board material and the liquid crystal material.
Description
Technical field
The present invention relates generally to a kind of filter, and be specifically related to a kind of continuously adjustabe band pass filter based on nematic crystal, this filter can be applicable in microwave electron system.
Background technology
Along with the fast development of electronic technology and the day by day crowded of frequency spectrum resource, hyundai electronics information system except possess high-performance and also towards multiband, the target fast development such as multi-functional, cost is low, lightweight, volume is little, reliability is high.Miniaturization, high-performance, low cost and the microwave filter with tunable characteristic, as the important component part in electronic system, realize miniaturized tunablely serving important function to microwave sub-system.Therefore, the research of tunable techniques, Reconfiguration Technologies becomes focus, the difficult point of current microwave disciplinary study.What existing tunable filter actualizing technology major part adopted is introduce tunable arrangement in circuit structure, such as: pin diode switch, ferrite and MEMS (micro electro mechanical system) (Micro-Electro-MechanicalSystem:MEMS) device.Above tunable filter designing technique some shortcomings of all existence more or less, such as: pin diode switch can only realize discontinuous adjustable, ferritic BREATHABLE BANDWIDTH is narrower, and the tuning voltage of MEMS is high and expensive.
Because liquid crystal has mobility, under some pattern, unstable flowing may be there is in liquid crystal, this unsure state is controlled by the change of electric field strength completely, and then cause the change of liquid crystal cell interior lights scattering phenomenon, birefringence and the change of polarised light transfer function etc., namely the optical property of liquid crystal in box there occurs change, and this phenomenon is called as the electro optic effect of liquid crystal.Adopt liquid crystal as electrooptical material, utilize liquid-crystal refractive-index to change and the characteristic of change with extra electric field, thus change liquid crystal material effective dielectric constant.Filter adjustable liquid crystal display phase shifter bias voltage, change the refractive index of liquid crystal molecule, namely by the refractive index of regulation voltage adjustable liquid crystal display material, the change of refractive index is directly equal to the change of liquid crystal effective dielectric constant, namely utilize liquid crystal to change in the dielectric anisotropy that biasing and biasing do not produce, thus the object of frequency modulation can be realized.Based on this thinking, devise liquid crystal microwave tunable filter.
Based on the important function of tunable filter in contemporary electronic systems, and some problems that existing designing technique exists, the tunable filter designing technique studied based on nematic crystal has very huge meaning and using value.
Summary of the invention
(1) technical problem that will solve
For solving the problem, the present invention proposes a kind of continuously adjustabe band pass filter based on nematic crystal, this filter can be applicable in microwave electron system, there is the advantages such as good linearity, with low cost, control is convenient, lightweight, be applied to the research of this vital microwave device of filter, effectively can not only overcome the shortcoming of conventional tune technology, and electronic system performance can be significantly improved.
(2) technical scheme
Based on a continuously adjustabe band pass filter for nematic crystal, it mainly comprises ground floor dielectric-slab, second layer dielectric layer, third layer metallic plate and liquid crystal; Being characterized in: described ground floor dielectric-slab is top layer dielectric-slab, and this dielectric-slab is square type, is a kind of printed circuit board (PCB), main carrying filter resonance unit, and input and output feeder line; Its upper and lower surface all has very thin metal level, is connected by plated-through hole; Described second layer dielectric layer is underlying dielectric plate, and this dielectric-slab is square type, and zone line hollows out and is formed as rectangular opening groove; Third layer metallic plate; Being affixed on the lower rear of above-mentioned bottom printed medium plate, is a slice rectangular metal, for carrying above-mentioned printed circuit board and nematic liquid crystalline material, and ground connection; The dielectric-slab that the second layer is with holes and third layer metallic plate combine the rectangular channel formed, and are used for placing liquid crystal.
Further, described ground floor dielectric-slab upper and lower surface has metal level, and the metal level wherein above ground floor dielectric-slab is metal micro-strip; Metal level below ground floor dielectric-slab is the metal structure of filter; Upper lower metal layer is connected by plated-through hole.
Further, described filter resonance unit is square bimodulus resonant element, and this resonant element is etched in the back side of top layer dielectric-slab.
Further, described input and output feeder line, is etched in the front of top layer dielectric-slab, and is connected, for the transmission of microwave signal and the feed-in of modulated voltage signal by the bimodulus resonant element of plated-through hole with the top layer dielectric-slab back side.
Further, when debugging, when modulation signal voltage is 0V, nematic liquid crystalline material molecule presents perpendicular to the arrangement of bimodulus resonant element, and dielectric constant is initial value and less; When modulation signal voltage is elevated to a certain degree, nematic liquid crystalline material molecule presents and is parallel to the arrangement of bimodulus resonant element, and its dielectric constant increases thereupon and reaches a maximum in the process.Because the dielectric constant of nematic liquid crystalline material is under modulation signal electric field action, along with the increase consecutive variations of voltage, make the resonance frequency consecutive variations of square double mode resonant element, realize continuously adjustable filter function.
(3) beneficial effect
The present invention compared with prior art, it has following beneficial effect: a kind of continuously adjustabe band pass filter based on nematic crystal of the present invention, this filter can be applicable in microwave electron system, there is the advantages such as good linearity, with low cost, control is convenient, lightweight, be applied to the research of this vital microwave device of filter, effectively can not only overcome the shortcoming of conventional tune technology, and electronic system performance can be significantly improved.
Accompanying drawing explanation
Fig. 1 is ground floor dielectric-slab front schematic view of the present invention.
Fig. 2 is ground floor dielectric-slab schematic rear view of the present invention.
Fig. 3 is second layer dielectric-slab schematic diagram of the present invention.
Fig. 4 is third layer metallic plate schematic diagram of the present invention.
Embodiment
As Figure 1-4, a kind of continuously adjustabe band pass filter based on nematic crystal, it mainly comprises ground floor dielectric-slab, second layer dielectric layer, third layer metallic plate and liquid crystal; Being characterized in: described ground floor dielectric-slab is top layer dielectric-slab, and this dielectric-slab is square type, is a kind of printed circuit board (PCB), main carrying filter resonance unit, and input and output feeder line; Its upper and lower surface all has very thin metal level, is connected by plated-through hole; Described second layer dielectric layer is underlying dielectric plate, and this dielectric-slab is square type, and zone line hollows out and is formed as rectangular opening groove; Third layer metallic plate; Being affixed on the lower rear of above-mentioned bottom printed medium plate, is a slice rectangular metal, for carrying above-mentioned printed circuit board and nematic liquid crystalline material, and ground connection; The dielectric-slab that the second layer is with holes and third layer metallic plate combine the rectangular channel formed, and are used for placing liquid crystal.
Wherein, described ground floor dielectric-slab upper and lower surface has metal level, and the metal level wherein above ground floor dielectric-slab is metal micro-strip; Metal level below ground floor dielectric-slab is the metal structure of filter; Upper lower metal layer is connected by plated-through hole.
Wherein, described filter resonance unit is square bimodulus resonant element, and this resonant element is etched in the back side of top layer dielectric-slab.
Wherein, described input and output feeder line, is etched in the front of top layer dielectric-slab, and is connected, for the transmission of microwave signal and the feed-in of modulated voltage signal by the bimodulus resonant element of plated-through hole with the top layer dielectric-slab back side.
Wherein, when debugging, when modulation signal voltage is 0V, nematic liquid crystalline material molecule presents perpendicular to the arrangement of bimodulus resonant element, and dielectric constant is initial value and less; When modulation signal voltage is elevated to a certain degree, nematic liquid crystalline material molecule presents and is parallel to the arrangement of bimodulus resonant element, and its dielectric constant increases thereupon and reaches a maximum in the process.Because the dielectric constant of nematic liquid crystalline material is under modulation signal electric field action, along with the increase consecutive variations of voltage, make the resonance frequency consecutive variations of square double mode resonant element, realize continuously adjustable filter function.
Embodiment recited above is only be described the preferred embodiment of the present invention, not limits the spirit and scope of the present invention.Under the prerequisite not departing from design concept of the present invention; the various modification that this area ordinary person makes technical scheme of the present invention and improvement; all should drop into protection scope of the present invention, the technology contents of request protection of the present invention, all records in detail in the claims.
Claims (5)
1., based on a continuously adjustabe band pass filter for nematic crystal, it mainly comprises ground floor dielectric-slab, second layer dielectric layer, third layer metallic plate and liquid crystal; Being characterized in: described ground floor dielectric-slab is top layer dielectric-slab, and this dielectric-slab is square type, is a kind of printed circuit board (PCB), main carrying filter resonance unit, and input and output feeder line; Its upper and lower surface all has very thin metal level, is connected by plated-through hole; Described second layer dielectric layer is underlying dielectric plate, and this dielectric-slab is square type, and zone line hollows out and is formed as rectangular opening groove; Third layer metallic plate; Being affixed on the lower rear of above-mentioned bottom printed medium plate, is a slice rectangular metal, for carrying above-mentioned printed circuit board and nematic liquid crystalline material, and ground connection; The dielectric-slab that the second layer is with holes and third layer metallic plate combine the rectangular channel formed, and are used for placing liquid crystal.
2. a kind of continuously adjustabe band pass filter based on nematic crystal according to claim 1, is characterized in that: described ground floor dielectric-slab upper and lower surface has metal level, and the metal level wherein above ground floor dielectric-slab is metal micro-strip; Metal level below ground floor dielectric-slab is the metal structure of filter; Upper lower metal layer is connected by plated-through hole.
3. a kind of continuously adjustabe band pass filter based on nematic crystal according to claim 1, is characterized in that: described filter resonance unit is square bimodulus resonant element, and this resonant element is etched in the back side of top layer dielectric-slab.
4. a kind of continuously adjustabe band pass filter based on nematic crystal according to claim 1, it is characterized in that: described input and output feeder line, be etched in the front of top layer dielectric-slab, and be connected, for the transmission of microwave signal and the feed-in of modulated voltage signal by the bimodulus resonant element of plated-through hole with the top layer dielectric-slab back side.
5. a kind of continuously adjustabe band pass filter based on nematic crystal according to claim 1, it is characterized in that: when debugging, when modulation signal voltage is 0V, nematic liquid crystalline material molecule presents perpendicular to the arrangement of bimodulus resonant element, and dielectric constant is initial value and less; When modulation signal voltage is elevated to a certain degree, nematic liquid crystalline material molecule presents and is parallel to the arrangement of bimodulus resonant element, and its dielectric constant increases thereupon and reaches a maximum in the process.Because the dielectric constant of nematic liquid crystalline material is under modulation signal electric field action, along with the increase consecutive variations of voltage, make the resonance frequency consecutive variations of square double mode resonant element, realize continuously adjustable filter function.
Priority Applications (1)
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| CN201410680583.7A CN104393378A (en) | 2014-11-24 | 2014-11-24 | Continuously adjustable band pass filter based on nematic liquid crystals |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105161799A (en) * | 2015-08-25 | 2015-12-16 | 电子科技大学 | Microwave adjustable filter |
| CN105489987A (en) * | 2016-01-18 | 2016-04-13 | 电子科技大学 | Substrate integrated waveguide microwave tunable filter based on liquid crystal material |
| WO2019233127A1 (en) * | 2018-06-08 | 2019-12-12 | 京东方科技集团股份有限公司 | Tunable band stop filter and drive method therefor, and electronic apparatus |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2014083634A1 (en) * | 2012-11-28 | 2014-06-05 | Dic株式会社 | Nematic liquid crystal composition and liquid crystal display element using same |
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- 2014-11-24 CN CN201410680583.7A patent/CN104393378A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014083634A1 (en) * | 2012-11-28 | 2014-06-05 | Dic株式会社 | Nematic liquid crystal composition and liquid crystal display element using same |
Non-Patent Citations (2)
| Title |
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| MANI YAZDANPANAHI 等: ""Millimeter-wave Liquid-Crystal-Based Tunable Bandpass Filter"", 《RADIO AND WIRELESS SYMPOSIUM，2012 IEEE》 * |
| 刘传运: ""左手媒质的构造及在微波工程中的应用研究"", 《中国博士学位论文全文数据库》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105161799A (en) * | 2015-08-25 | 2015-12-16 | 电子科技大学 | Microwave adjustable filter |
| CN105489987A (en) * | 2016-01-18 | 2016-04-13 | 电子科技大学 | Substrate integrated waveguide microwave tunable filter based on liquid crystal material |
| CN105489987B (en) * | 2016-01-18 | 2018-06-19 | 电子科技大学 | A kind of substrate integration wave-guide microwave tunable filter based on liquid crystal material |
| WO2019233127A1 (en) * | 2018-06-08 | 2019-12-12 | 京东方科技集团股份有限公司 | Tunable band stop filter and drive method therefor, and electronic apparatus |
| US11309616B2 (en) | 2018-06-08 | 2022-04-19 | Boe Technology Group Co., Ltd. | Tunable band-stop filter, method of driving the same and electronic device |
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Application publication date: 20150304 |
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