CN104037477A - Multi-band tunable microstrip band-pass filter - Google Patents
Multi-band tunable microstrip band-pass filter Download PDFInfo
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- CN104037477A CN104037477A CN201410223931.8A CN201410223931A CN104037477A CN 104037477 A CN104037477 A CN 104037477A CN 201410223931 A CN201410223931 A CN 201410223931A CN 104037477 A CN104037477 A CN 104037477A
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Abstract
The invention discloses a multi-band tunable microstrip band-pass filter which comprises a three-layer structure: a front metal microstrip line, a middle dielectric plate layer, input and output ports and an earthing metal through hole, and a metal coating at the back of a dielectric plate, wherein the metal microstrip line is a symmetric resonator consisting of a half-wavelength uniform impedance line resonator and an open-loop dual-mode resonator; the two resonators share input and output coupling lines; and a variable capacitance diode is loaded between the tail end of the open-loop dual-mode resonator and the earthing metal through hole to form a tunable structure. The filter is compact in structure, low in passband insertion loss, steep in passband edge and high in selectivity, and meets a development trend of filter miniaturization.
Description
Technical field
The present invention relates to a kind of multi-band tunable microstrip bandpass filter, belong to field of wireless communications systems, realize three passbands adjustable in, there is high Out-of-band rejection degree, and meet miniaturization feature.
Background technology
The application band of communication system is all gathered in radio frequency and microwave frequency band low-frequency range at present, and this makes frequency spectrum resource crowded especially.For improve power system capacity and avoid system and adjacent channel between interference, a plurality of communications bands that can simultaneously work are set in communication system and seem very necessary.Yet realize double frequency or multiband communication, each frequency range needs independently radio-frequency front-end element, this make whole system volume and power consumption larger, cost is higher.If radio-frequency front-end element design can be become to two-band or multiband form, can greatly reduce volume, cost and the power consumption of system, strengthen its reliability, promote communication system to miniaturization, high integration development.
In modern wireless telecommunication system, electrically tunable filter is in receiver between antenna and frequency mixer, and its effect is to select useful signal from the received a large amount of frequency spectrums of antenna, suppresses harmful interference spectrum, thereby improves the signal to noise ratio of receiver.Multi-band tunable filter can make single equipment have the ability to cover different frequency range and support different communication standards, thereby can meet the requirement that future mobile communications broadband covers.The present invention is based on electrically tunable filter technology, designed the tunable band pass filter of a kind of three frequency band, its Out-of-band rejection degree is higher, and compact conformation, is convenient to the system integration, has met Modern wireless communication miniaturization, high performance requirement.By the coupling between introducing source and load, when on-load voltage is lower, increased extra finite frequency transmission zero, improved the attenuation characteristic of filter.
Summary of the invention
That the object of filter of the present invention is is large for traditional multiband system bulk, system cost is high, and the bank of filters being comprised of multichannel one-segment filter, and signal is processed the single shortcoming of frequency range, and a kind of band pass filter of multi-band tunable is provided.By introducing input and output, be coupling in on-load voltage and increased the outer transmission zero of band when lower, in the first and the 3rd passband, centre frequency has realized 760MHz and 800MHz is adjustable, and filter construction compactness, has realized the miniaturization of filter.
For achieving the above object, design of the present invention is:
(1) on the micro-basis with open-loop resonator of tradition, portion adds Ψ type joint within it, achieves bimodulus resonance, by changing two kinds of mode frequencies, regulates band connection frequency to reach adjustable effect.
(2) the microstrip line end of open loop dual-mode resonator adds variable capacitance diode, changes DC bias circuit reverse biased, thereby the electrical length that makes its capacitance variations change resonator reaches adjustable object.
(3) utilize the folded form structure of traditional uniform impedance resonator (UIR), itself and open loop dual-mode resonator are shared to input and output coupling line, the resonance frequency of independent regulation open loop dual-mode resonator, reaches the object of asynchronous adjusting.
(4) the present invention adopts following dielectric-slab material: medium substrate selects dielectric constant to be
=2.2, thickness
h=0.508mm.
(5) circuit board is divided into three layers, and front is metal micro-strip line structure, and centre is medium flaggy and input/output port, and medium plate back is layer of metal coating, and wherein two sub-miniature A connectors are welded at input/output port place, for actual measurement.Front metal microstrip line construction is comprised of a uniform impedance impedance line, open loop dual-mode resonator and input and output coupling line, and open loop dual-mode resonator end adds variable capacitance diode, by changing bias voltage, reaches the adjustable object of frequency.
According to foregoing invention design, the present invention adopts following technical proposals:
A kind of multi-band tunable microstrip bandpass filter comprises three-decker: positive metal micro-strip line, the medium flaggy of centre and the coat of metal of input/output port and grounded metal through hole and medium sheet material reverse side.Described metal micro-strip line consists of the resonator of symmetrical structure a half-wavelength uniform impedance line resonator and open loop dual-mode resonator, two resonators share input and output coupling line, between open loop dual-mode resonator end and grounded metal through hole, load variable capacitance diode, form tunable structure.
Described open loop dual-mode resonator forms by loading Ψ shape open stub in the middle of an opening quadratic loop resonator, symmetrical configuration, and the resonance frequency of two kinds of patterns of generation, therefore available even odd mode theory is analyzed.Described half-wavelength uniform impedance line resonator adopts bent structure, meets the demand of miniaturization.Described input and output coupling is that open loop dual-mode resonator and half-wavelength uniform impedance line share an input and output coupling line, by aperture-coupled, has increased extra finite frequency transmission zero when on-load voltage is lower, has improved the attenuation characteristic of filter.
Described biasing circuit utilizes variable capacitance diode, and the electric capacity and the resistance that on open loop dual-mode resonator, load 1000pF are 10k
resistance, and load variable capacitance diode at minor matters end, as variable capacitance diode BB857, change in voltage is when 7.5-15V.Wherein at split ring end, add two identical variable capacitance diodes, capacitance variations, at 0.7-1.5pF, adds a variable capacitance diode and save end in Ψ type, and capacitance changes at 0.4-0.9pF.
Described medium flaggy is dielectric constant
dielectric-slab, this dielectric-slab thickness h=0.508mm.
The coat of metal of described metal micro-strip line and reverse side part can be the good metal material of electric conductivity, as gold or silver or copper.
The present invention compared with the prior art, has following apparent outstanding substantive distinguishing features and remarkable advantage:
1. filter of the present invention adopts open loop dual-mode resonator structure, by add Ψ type in the middle of split ring, saves, and makes the structure of resonator compacter, has simplified the complexity of design, has met the requirement of Modern Filter small design.
2. by the interpolation of biasing circuit, adjustable thereby the capacitance of regulation voltage change variable capacitance diode is realized passband, there is tuned speed fast, frequency tuning range is wide, and debugging is convenient, low cost and other advantages.
3. by introducing input and output, be coupled, when on-load voltage is lower, increased extra finite frequency transmission zero, improved the frequency selectivity of filter.
4. at open loop dual-mode resonator end, add variable capacitance diode, realize the adjustable of two band connection frequencies, and the band connection frequency being caused by uniform impedance line resonance can remain unchanged.
accompanying drawing explanation
Fig. 1 is the structural representation of the tunable microstrip bandpass filter of many passbands.
Fig. 2 is the structural representation of the tunable microstrip bandpass filter of many passbands upper strata metal micro-strip line.
Fig. 3 is variable capacitance diode schematic diagram.
Fig. 4 is the overall structure schematic diagram of the tunable microstrip bandpass filter of the many passbands of the present invention
Fig. 5 is the frequency response schematic diagram of voltage microstrip filter while being 15V.
Fig. 6 is that voltage can timing between 7.5-15V, the S11 schematic diagram of microstrip filter.
Fig. 7 is that voltage can timing between 7.5-15V, the S21 schematic diagram of microstrip filter.
Embodiment
Below in conjunction with accompanying drawing, a preferred embodiment of the present invention is elaborated:
Embodiment mono-:
Referring to Fig. 1, many passbands are tunable, and microstrip bandpass filter comprises three-decker: medium flaggy (2) and input/output port (3,4) and the grounded metal through hole (5) of positive metal micro-strip line (1), centre, and the coat of metal of medium sheet material reverse side.Described metal micro-strip line is: the resonator that consists of symmetrical structure a half-wavelength uniform impedance line resonator (1-1) and open loop dual-mode resonator (1-2), therefore available even odd mode theory is analyzed, two resonators share input and output coupling line, between open loop dual-mode resonator end and grounded metal through hole (5), load variable capacitance diode, form tunable structure.
Embodiment bis-:
The present embodiment and embodiment mono-are basic identical, positive metal micro-strip line is as Fig. 2, special feature is: described open loop dual-mode resonator forms by loading Ψ shape open stub (2) in the middle of an opening quadratic loop resonator (1), its symmetrical configuration, the resonance frequency of two kinds of patterns of generation.Described half-wavelength uniform impedance line (3) resonator adopts bent structure, has reduced the area of filter, meets the demand of miniaturization.Described input and output coupling line (4), by aperture-coupled, has increased extra finite frequency transmission zero when on-load voltage is lower, has improved the attenuation characteristic of filter.Described medium flaggy is dielectric constant
dielectric-slab, this dielectric-slab thickness h=0.508mm.
Embodiment tri-:
The present embodiment and embodiment bis-are basic identical, special feature is between open loop dual-mode resonator and grounded metal through hole, to load variable capacitance diode (Fig. 3), by DC bias circuit, to variable capacitance diode, load reverse biased, the resonance frequency that changes parity mode reaches band pass filter centre frequency and the adjustable object of bandwidth.
Fig. 4 is the structural representation of the present embodiment, through design, emulation and optimization, finally determines that the concrete size of this many passbands variable band-pass filter is as follows:
L1=8.0mm，?L2=7.75mm，L3=7.6mm，L4=6.1mm，L5=1.6mm，L6=0.8mm，
W1=3.3mm,?W2=4.32mm,?W3=3.75mm,?W4=2.75mm，W5=4.0mm，W6=2.8mm，
D1=0.3mm，D2=0.25mm，D3=0.6mm，D4=0.3mm，D5=0.4mm，d=0.508mm，
r=0.4mm
Based on said method, designed three frequency band band microstrip filters that centre frequency is 2.68GHz/4.66GHz/5.88GHz, by Electromagnetic Simulation software, Sonnet carries out emulation, debugging.
Fig. 5 has shown when voltage is 15V, the simulation result of microstrip filter.
Fig. 6 and Fig. 7 have shown that respectively voltage can timing between 7.5-15V, the S11 of microstrip filter and S21 simulation result.Simulation result shows
(1) this filter has been realized the response characteristic of three frequency bands, and the first frequency band and the 3rd frequency band all realized adjustablely, and the centre frequency of the second frequency band and bandwidth remain constant.
(2) when on-load voltage is lower, between the first frequency band and the second frequency band, have a transmission zero, passband cut-off edge is precipitous, and in passband, Insertion Loss is lower, and selectivity is good.
The adjustable extent of (3) first mid-band frequencies is adjustable at 2.1GHz-2.86GHz, and the 3rd mid-band frequency is adjustable within the scope of 5.3GHz-6.1GHz.Along with frequency raises, the absolute bandwidth of each frequency band broadens gradually.
(4) microstrip structure is simple, and size also obtains miniaturization, prints simple and easyly, and spillage of material is relatively little.
Claims (4)
1. a multi-band tunable microstrip bandpass filter, comprise three-decker: positive metal micro-strip line (1), middle medium flaggy (2) and input/output port (3, 4) and grounded metal through hole (5), and the coat of metal of medium sheet material reverse side, it is characterized in that: described metal micro-strip line (1) consists of the resonator of symmetrical structure a half-wavelength uniform impedance line resonator (1-1) and open loop dual-mode resonator (1-2), two resonator (1-1, 1-2) share input and output coupling line (1-3), between open loop dual-mode resonator (1-2) end and grounded metal through hole (5), load variable capacitance diode, form tunable structure.
2. multi-band tunable microstrip bandpass filter according to claim 1, it is characterized in that: described open loop dual-mode resonator (1-2) forms by loading Ψ shape open stub in the middle of an opening quadratic loop resonator, its symmetrical configuration, the resonance frequency of two kinds of patterns of generation; Described half-wavelength uniform impedance line resonator (1-1) adopts bending type structure, has reduced the area of filter, meets the demand of miniaturization; Described input and output coupling line (1-3), by aperture-coupled, produces extra finite frequency transmission zero when on-load voltage is lower, has improved the attenuation characteristic of filter.
3. multi-band tunable microstrip bandpass filter according to claim 1, it is characterized in that: between described open loop dual-mode resonator (1-2) and grounded metal through hole (5), load variable capacitance diode, by DC bias circuit, to variable capacitance diode, load reverse biased, the resonance frequency that changes parity mode reaches band pass filter centre frequency and the adjustable object of bandwidth.
4. multi-band tunable microstrip bandpass filter according to claim 1, is characterized in that: described medium flaggy (2) is dielectric constant
dielectric-slab, this dielectric-slab thickness h=0.508mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410223931.8A CN104037477A (en) | 2014-05-26 | 2014-05-26 | Multi-band tunable microstrip band-pass filter |
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| CN201410223931.8A CN104037477A (en) | 2014-05-26 | 2014-05-26 | Multi-band tunable microstrip band-pass filter |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104795614A (en) * | 2015-04-07 | 2015-07-22 | 上海大学 | Broad-stopband electrically-tunable dual-frequency band-pass filter |
| CN105470606A (en) * | 2015-12-29 | 2016-04-06 | 成都九洲迪飞科技有限责任公司 | Band-pass filter with adjustable zero point |
| CN105762466A (en) * | 2016-04-08 | 2016-07-13 | 华南理工大学 | Two electrically tunable passband-equipped three frequency band pass filter |
| CN109449548A (en) * | 2018-11-06 | 2019-03-08 | 杨涛 | Reconfigurable multifunctional filter based on half-wave resonator |
| CN111147074A (en) * | 2020-01-08 | 2020-05-12 | 重庆邮电大学 | 5G communication frequency source based on phase-adjustable open-loop resonator structure |
| CN111180297A (en) * | 2020-01-03 | 2020-05-19 | 电子科技大学 | Dual-band microstrip line slow wave structure |
| CN115036660A (en) * | 2022-06-16 | 2022-09-09 | 电子科技大学 | Microstrip filter with dynamically tunable working bandwidth and adjusting method |
| CN115863942A (en) * | 2022-12-13 | 2023-03-28 | 天津理工大学 | Double-passband independently adjustable band-pass filter with constant bandwidth |
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| CN102361110A (en) * | 2011-10-08 | 2012-02-22 | 上海大学 | Small-sized double-module double-frequency micro-strip filter |
| CN103187599A (en) * | 2013-03-09 | 2013-07-03 | 西安电子科技大学 | Band-gap adjustable micro-strip ultra-wide band filter |
| CN103515680A (en) * | 2012-06-18 | 2014-01-15 | 中国科学院深圳先进技术研究院 | Dual-mode band-pass filter and multi-order band-pass filter formed by the same |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104795614A (en) * | 2015-04-07 | 2015-07-22 | 上海大学 | Broad-stopband electrically-tunable dual-frequency band-pass filter |
| CN105470606A (en) * | 2015-12-29 | 2016-04-06 | 成都九洲迪飞科技有限责任公司 | Band-pass filter with adjustable zero point |
| CN105470606B (en) * | 2015-12-29 | 2018-07-03 | 成都九洲迪飞科技有限责任公司 | The adjustable bandpass filter of zero |
| CN105762466A (en) * | 2016-04-08 | 2016-07-13 | 华南理工大学 | Two electrically tunable passband-equipped three frequency band pass filter |
| CN105762466B (en) * | 2016-04-08 | 2019-01-18 | 华南理工大学 | A kind of tool there are two can electricity adjust three band-pass filters of passband |
| CN109449548A (en) * | 2018-11-06 | 2019-03-08 | 杨涛 | Reconfigurable multifunctional filter based on half-wave resonator |
| CN109449548B (en) * | 2018-11-06 | 2019-10-29 | 杨涛 | Reconfigurable multifunctional filter based on half-wave resonator |
| CN111180297A (en) * | 2020-01-03 | 2020-05-19 | 电子科技大学 | Dual-band microstrip line slow wave structure |
| CN111180297B (en) * | 2020-01-03 | 2021-03-30 | 电子科技大学 | Dual-band microstrip line slow wave structure |
| CN111147074A (en) * | 2020-01-08 | 2020-05-12 | 重庆邮电大学 | 5G communication frequency source based on phase-adjustable open-loop resonator structure |
| CN115036660A (en) * | 2022-06-16 | 2022-09-09 | 电子科技大学 | Microstrip filter with dynamically tunable working bandwidth and adjusting method |
| CN115863942A (en) * | 2022-12-13 | 2023-03-28 | 天津理工大学 | Double-passband independently adjustable band-pass filter with constant bandwidth |
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Application publication date: 20140910 |