CN202363565U - High-selectivity double-band-pass filter with independently tunable passbands - Google Patents
High-selectivity double-band-pass filter with independently tunable passbands Download PDFInfo
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- CN202363565U CN202363565U CN2011204630933U CN201120463093U CN202363565U CN 202363565 U CN202363565 U CN 202363565U CN 2011204630933 U CN2011204630933 U CN 2011204630933U CN 201120463093 U CN201120463093 U CN 201120463093U CN 202363565 U CN202363565 U CN 202363565U
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Abstract
The utility model discloses a high-selectivity double-band-pass filter with independently tunable passbands, which comprises an upper micro-strip structure, an intermediate medium substrate and a lower grounding metal plate. The filter comprises four resonators, each resonator comprises a micro-strip line and a variable capacitance diode and is a quarter-wave resonator, and the resonators are symmetrically arranged by centering on a central vertical axis of the micro-strip structure. The first resonator and the second resonator utilize the micro-strip lines which are directly connected onto the resonators and parallelly-coupled with the resonators as feed structures, and the third resonator and the fourth resonator utilize the micro-strip lines parallelly-coupled with the resonators as feed structures. Besides, the high-selectivity double-band-pass filter generates transmission zero by means of a pseudo-interdigital structure so as to be higher in selectivity. The high-selectivity double-band-pass filter has the advantages that the two passbands are tunable in central frequency and independently tunable.
Description
Technical field
The utility model relates to the adjustable dual band pass filter of a kind of centre frequency, particularly relates to a kind of centre frequency and is independent of each other between two passbands when tuning, can be applicable to the adjustable double band pass filter in the RF front-end circuit.
Background technology
Current society, along with the development of radio communication, low-cost, high performance restructural Radio Frequency Subsystem be designed to hot issue.The restructural communication system has very urgent demand for the tunable filter that can cover big frequency range.
The trim that present many researchers are different with many kinds is used for the design of variable band-pass filter, and several kinds of typical methods are wherein arranged.Thereby first method is the length change resonance frequency that changes resonator through variable capacitance diode; Like J.Long and C.Z.Li, " A tunable microstrip bandpass filter with two independently adjustable transmission zeros, " IEEE Microw.Wireless Compon.Lett.; Vol.21; No.2, pp.74-76, Feb.2010.5 ± 0.5?Second method is to adopt the PIN diode structure to design variable band-pass filter; Like G.L.Dai and M.Y.Xia, " Design of compact dual-band switchable bandpass filter, " Electronics Letters; Vol.45; No.10, pp.506-507, May.2009.The third method is to adopt ferrite component design tunable filter, like M.Norling, and D.Kuylenstierna; A.Vorobiev, and S.Gevorgian, " Layout optimization of small-size ferroelectric parallel-plate varactors; " IEEE Trans.Microw.Theory Tech., vol.58, no.6; Pp.1475-1484, June.2010.What the utility model adopted is first method---utilize variable capacitance diode to change resonance frequency.
Present stage, single-pass band tunable filter has caused a lot of concerns.Like V.Sekar; M.Armendariz, and K.Entesari. " A 1.2-1.6 GHz substrate-integrated-waveguide RF MEMS tunable filter, " IEEE Trans.Microw.Theory Tech.; Vol.59; No.4, pp.866-876, Apr.2010.5 ± 0.5.In order further to optimize the performance of single-pass band tunable filter, domestic researcher adopts lamped element to suppress the harmonic wave of passband.Like X.Y.Zhang and Q.Xue, " High-selectivity tunable bandpass filters with harmonic suppression, " IEEE Trans.Microw.Theory Tech., vol.58, no.4, pp.964-969, Apr.2010.It is adjustable that but single-pass band tunable filter can only be implemented in the single-frequency scope, so its frequency coverage is very limited.In order to address this problem, the utility model provides a kind of high selectivity dual band pass filter with independent adjustable passband.
The utility model content
The purpose of the utility model is to overcome the above-mentioned deficiency that prior art exists, and the high selectivity dual band pass filter with independent adjustable passband is provided.
For realizing the utility model purpose, the technical scheme that the utility model adopted is following:
Have the high selectivity dual band pass filter of independent adjustable passband, comprise upper strata microstrip structure, intermediate layer medium substrate and lower floor's grounding plate; The upper strata microstrip structure is attached to intermediate layer medium substrate upper surface, and lower floor's grounding plate is attached to intermediate layer medium substrate lower surface; The upper strata microstrip structure comprises port feed line, port microstrip line and four resonators; Four resonators all are the quarter-wave resonance devices; Four resonators are arranged into symmetrical structure; Two resonator structures that are positioned at the top are identical, and two resonator structures that are positioned at the below are identical, the port microstrip line above two resonators and below two resonators between; Two resonators that are positioned at the top directly link to each other and parallel coupling with the port feed line, are positioned at two resonators and the parallel coupling of port feed line of below.Coupled modes are coupled modes that a kind of electric coupling mixes with the magnetic coupling between first resonator, second resonator, the 3rd resonator and the 4th resonator and the port feed line.
In the above-mentioned high selectivity dual band pass filter with independent adjustable passband; Be positioned at upper left first resonator and comprise first variable capacitance diode, coupled microstrip line part and non-coupled microstrip line part; Wherein the coupled microstrip line part is connected in sequence by the 4th microstrip line, the 5th microstrip line and the 6th microstrip line; Non-coupled microstrip line partly comprises first microstrip line, second microstrip line and the 3rd microstrip line; One end of first microstrip line links to each other with the negative pole of first variable capacitance diode; The positive pole of first variable capacitance diode links to each other with the lower floor grounded metal through the metallization via hole that passes the intermediate layer medium substrate through an electric capacity; First microstrip line, second microstrip line, the 3rd microstrip line, the 4th microstrip line, the 5th microstrip line and the 6th microstrip line are connected in order, and the metallization via hole that the 6th microstrip line end passes the intermediate layer medium substrate links to each other with the lower floor grounded metal; The 3rd resonator that is positioned at the lower left comprises the 3rd variable capacitance diode and coupled microstrip line part; Wherein the coupled microstrip line part is connected in sequence by the tenth microstrip line, the 11 microstrip line; One end of the tenth microstrip line links to each other with the negative pole of the 3rd variable capacitance diode; The positive pole of the 3rd variable capacitance diode links to each other with the lower floor grounded metal through the metallization via hole that passes the intermediate layer medium substrate through an electric capacity, and the tenth microstrip line other end links to each other with an end of the 11 microstrip line; The metallization via hole that the other end of the 11 microstrip line passes the intermediate layer medium substrate links to each other with the lower floor grounded metal.
In the above-mentioned high selectivity dual band pass filter with independent adjustable passband, the electrical length L+ Δ L that is positioned at upper left resonator is 1/4th of the corresponding wavelength X of the low resonant frequency f of said dual band pass filter; Wherein, L is actual microstrip line length, and Δ L is first variable capacitance diode equivalence microstrip line length of upper left first resonator; Actual microstrip line length L is the length sum of first microstrip line, second microstrip line, the 3rd microstrip line, the 4th microstrip line, the 5th microstrip line and the 6th microstrip line; Length between the coupled zone equals the 4th microstrip line, the length summation of the 5th microstrip line and the 6th microstrip line; The electrical length L '+Δ L ' that is positioned at the resonator of lower left for the corresponding wavelength X of the high resonance frequency f ' of said dual band pass filter ' 1/4th; Wherein L ' is actual microstrip line length, and Δ L ' is the 3rd variable capacitance diode equivalence microstrip line length of the 3rd resonator of lower left; Actual microstrip line length L ' be the length sum of the tenth microstrip line, the 11 microstrip line; Length between the coupled zone equals the length summation of the tenth microstrip line, the 11 microstrip line.
In the above-mentioned high selectivity dual band pass filter with independent adjustable passband; The coupled microstrip line part that is positioned at upper left resonator is in turn connected into n shape structure by the 4th microstrip line, the 5th microstrip line and the 6th microstrip line, and the coupled microstrip line part that is positioned at the resonator of lower left is in turn connected into L shaped structure by the tenth microstrip line, the 11 microstrip line.
In the above-mentioned high selectivity dual band pass filter with independent adjustable passband; Said port feed line comprises coupling feed line part and non-coupling feed line part; The feed line that wherein is coupled partly comprises two parts up and down, and top is connected and composed by the 7th microstrip line, the 8th microstrip line and the 9th microstrip line successively; The 7th microstrip line is connected with the 4th microstrip line and realizes stronger coupling between the feed line resonator; The lower part is connected and composed by the 13 microstrip line and the 14 microstrip line successively; The non-coupling feed line part of port feed line is made up of the 12 microstrip line; Be provided with the electromagnetic coupled gap that width is 0.2 ± 0.05mm between the coupling feed line part resonator coupled microstrip line part of port feed line; The port microstrip line partly comprises the 16 microstrip line; First resonator, second resonator are positioned at the 16 microstrip line top, and the 3rd resonator, the 4th resonator are positioned at the 16 microstrip line below.
In the above-mentioned high selectivity dual band pass filter with independent adjustable passband; The top of the coupling feed line of port feed line connects and composes n shape structure successively by the 7th microstrip line, the 8th microstrip line and the 9th microstrip line, is positioned at the inboard of the first resonator coupled microstrip line part n shape structure; The 7th microstrip line, the 8th microstrip line and the 9th little band are parallel with the 6th microstrip line with the 4th microstrip line, the 5th microstrip line respectively; The lower part of the coupling feed line of port feed line connects and composes L shaped structure successively by the 13 microstrip line and the 14 microstrip line, is positioned at the inboard of resonator coupled microstrip line partial L shape structure; The 13 microstrip line is parallel with the 11 microstrip line with the tenth microstrip line respectively with the 14 microstrip line.
In the above-mentioned high selectivity dual band pass filter with independent adjustable passband; The turnable resonator frequency range of said adjustable double band pass filter is respectively 570-690MHz and 1.156-1.336GHz; The length of first microstrip line is 2.6 ± 0.2mm, and the length of second microstrip line is 12.4 ± 0.3mm, and the length of the 3rd microstrip line is 3.0 ± 0.1mm; The length of the 4th microstrip line is 13.6 ± 0.2mm; The length of the 5th microstrip line is 9.1 ± 0.4mm, and the length of the 6th microstrip line is 14.1 ± 0.3mm, and the coupling spacing between said four resonators and the port feed line is 0.2 ± 0.05mm; The width of first microstrip line, second microstrip line, the 3rd microstrip line, the 4th microstrip line, the 5th microstrip line and the 6th microstrip line is 0.7 ± 0.1mm; The width of the 7th microstrip line, the 8th microstrip line and the 9th microstrip line is 0.9mm, and the width of the 16 microstrip line is 1.84mm, and the characteristic impedance of the 16 microstrip line is 50 Ω; The length of the tenth microstrip line, the 11 microstrip line is respectively 10.5 ± 0.5mm and 7.0 ± 0.4mm, and the gap of the tenth microstrip line and the 13 microstrip line is 0.2 ± 0.05mm; Gap between first resonator, second resonator and the 3rd resonator, the 4th resonator is 0.4mm; The length of the 15 microstrip line is 1.8 ± 0.2mm, and the spacing between each bar microstrip line is 0.2 ± 0.05mm; The variable capacitance diode of first resonator, second resonator is provided with identical bias voltage, and the variable capacitance diode of the 3rd resonator, the 4th resonator is provided with identical bias voltage.
In addition, the 15 microstrip line adopts 6 microstrip lines to constitute pseudo-interdigital structure and is used for producing the selectivity that transmission zero strengthens passband.
With respect to prior art, the utlity model has following advantage:
(1) has two adjustable passbands.For common variable band-pass filter, often has only an adjustable passband.And the utility model has realized that two passbands are adjustable, from having increased the frequency coverage of filter greatly.
Can realize independent tuning between (2) two passbands, be independent of each other.In the utility model, an adjustable passband is in the process that centre frequency changes, and another passband is unaffected, realizes independent tuning fully.Can make two passband places of working more stable.
Description of drawings
Fig. 1 is the high selectivity dual band pass Filter Structures figure with independent adjustable passband.
Fig. 2 is the topological structure of adjustable double band pass filter.
Fig. 3 a is the equivalent schematic diagram of the electromagnetic coupled structure of adjustable double band pass filter.
Fig. 3 b is the equivalent circuit diagram of a resonator under different bias voltages of adjustable double band pass filter.
Fig. 4 is the high selectivity dual band pass Filter Structures sketch map with independent adjustable passband.
Fig. 5 a is the transmission characteristic simulation curve figure that adjustable double band pass filter lower passband partly changes centre frequency.
Fig. 5 b is the transmission characteristic simulation curve figure that adjustable double band pass filter upper passband partly changes centre frequency.
Fig. 6 a is the transmission characteristic actual measurement profile figure that adjustable double band pass filter lower passband partly changes centre frequency.
Fig. 6 b is the transmission characteristic actual measurement profile figure that adjustable double band pass filter upper passband partly changes centre frequency.
Embodiment
Below in conjunction with accompanying drawing the utility model is done further detailed explanation, but the utility model requires the scope of protection to be not limited to down the scope of example statement.
As shown in Figure 1, have the independently high selectivity dual band pass filter of adjustable passband, comprise upper strata microstrip structure, intermediate layer medium substrate and lower floor's grounding plate; The upper strata microstrip structure is attached to intermediate layer medium substrate upper surface, and lower floor's grounding plate is attached to intermediate layer medium substrate lower surface; The upper strata microstrip structure comprises port feed line, port microstrip line and four resonators; Four resonators all are the quarter-wave resonance devices, and four resonators are arranged into symmetrical structure, and first resonator, second resonator structure that are positioned at the top are identical, and the 3rd resonator, the 4th resonator structure that are positioned at the below are identical; Be positioned at upper left first resonator and comprise first variable capacitance diode 17, coupled microstrip line part and non-coupled microstrip line part; The coupled microstrip line of first resonator part is in turn connected into n shape structure by the 4th microstrip line 4, the 5th microstrip line 5 and the 6th microstrip line 6; The non-coupled microstrip line of resonator partly comprises first microstrip line 1, second microstrip line 2, the 3rd microstrip line 3; One end of first microstrip line 1 links to each other with the negative pole of first variable capacitance diode 17; The positive pole of first variable capacitance diode 17 links to each other with the lower floor grounded metal through the metallization via hole that passes the intermediate layer medium substrate through an electric capacity; First microstrip line 1, second microstrip line 2, the 3rd microstrip line 3, the 4th microstrip line 4, the 5th microstrip line 5 are connected with the 6th microstrip line 6 in order, and the metallization via hole that the 6th microstrip line 6 ends pass the intermediate layer medium substrate links to each other with the lower floor grounded metal; The 3rd resonator that is positioned at the lower left comprises the 3rd variable capacitance diode 18, coupled microstrip line part, and the coupled microstrip line part of the 3rd resonator is in turn connected into L shaped structure by the tenth microstrip line 10, the 11 microstrip lines 11; One end of the tenth microstrip line 10 links to each other with the negative pole of the 3rd variable capacitance diode 18; The positive pole of the 3rd variable capacitance diode 18 links to each other with the lower floor grounded metal through the metallization via hole that passes the intermediate layer medium substrate through an electric capacity, and the tenth microstrip line 10 other ends link to each other with the 11 microstrip line 11; The metallization via hole that the other end of the 11 microstrip line 11 passes the intermediate layer medium substrate links to each other with the lower floor grounded metal.
Said port feed line comprises coupling feed line part and non-coupling feed line part; The feed line that wherein is coupled partly comprises two parts up and down; The top of coupling feed line connects and composes n shape structure successively by the 7th microstrip line 7, the 8th microstrip line 8 and the 9th microstrip line 9, is positioned at the inboard of the first resonator coupled microstrip line part n shape structure; The 7th microstrip line 7, the 8th microstrip line 8 and the 9th microstrip line 9 are parallel with the 6th microstrip line 6 with the 4th microstrip line 4, the 5th microstrip line 5 respectively; The 7th microstrip line 7 is connected with the 4th microstrip line 4 and realizes stronger coupling between the feed line resonator; The lower part of coupling feed line connects and composes n shape structure successively by the 12 microstrip line the 12, the 13 microstrip line 13 and the 14 microstrip line 14, is positioned at the inboard of resonator coupled microstrip line partial L shape structure; The 13 microstrip line 13 is parallel with the 11 microstrip line 11 with the tenth microstrip line 10 respectively with the 14 microstrip line 14; The non-coupling feed line of port feed line partly comprises the 16 microstrip line 16.First resonator, second resonator are positioned at the 16 microstrip line 16 tops, and the 3rd resonator, the 4th resonator are positioned at the 16 microstrip line 16 belows.The characteristic impedance of the 16 microstrip line 16 is 50 Ω; Be provided with the electromagnetic coupled spacing that width is 0.2 ± 0.05mm between resonator coupled microstrip line part and the port feed line coupling feed line part, realize electromagnetic coupled; The electromagnetic coupled spacing is decided by the coupling power.
First resonator is made up of the microstrip line and first variable capacitance diode 17, and microstrip line one end connects the negative pole of first variable capacitance diode 17, and the metallization via hole that the other end passes the intermediate layer medium substrate links to each other with the lower floor grounded metal; First microstrip line 1 of first resonator, second microstrip line 2, the 3rd microstrip line 3, the 4th microstrip line 4, the 5th microstrip line 5 and the 6th microstrip line 6 length and add that the total length of the microstrip line of first variable capacitance diode, 17 equivalences is the filter quarter-wave corresponding than low resonant frequency.The resonance frequency of first resonator is mainly regulated through the bias voltage of first variable capacitance diode 17.When ignoring ghost effect, first variable capacitance diode 17 can equivalence becomes the microstrip line of section termination open circuit.Shown in Fig. 3 a, hatched example areas representes that real microstrip line length is L; It is the microstrip line of Δ L that 17 equivalences of first variable capacitance diode become length; The electrical length L+ Δ L of first resonator is 1/4th of the corresponding wavelength X of resonance frequency f; Resonance frequency f and electrical length are inversely proportional to, promptly
The bias voltage of first variable capacitance diode 17 of adjustment resonator, then the equivalent capacity of first variable capacitance diode 17 can change, and its equivalent microstrip line length also can change thereupon, thus resonance frequency changes; Shown in Fig. 3 b, as the equivalent capacity C of first variable capacitance diode 17
V1＞C
V2The time, corresponding equivalent microstrip line length Δ L
1＞Δ L
2, corresponding resonance frequency f
1＜f
2Therefore through the bias voltage of adjustment first variable capacitance diode 17, can adjust the centre frequency of pass filter.The minimum f of the resonance frequency tuning range of selected first variable capacitance diode 17 and definite filter work
MinWith maximum f
MaxAfterwards, can confirm the excursion of the equivalent microstrip line length of first variable capacitance diode 17, the total length according to equivalent microstrip line is the length L that quarter-wave characteristic just can be confirmed actual microstrip line then.In fact part microstrip line length L
1Length sum for first microstrip line 1 among Fig. 1, second microstrip line 2, the 3rd microstrip line 3, the 4th microstrip line 4, the 5th microstrip line 5 and the 6th microstrip line 6.In like manner, lower part microstrip line length L
2Length sum for the tenth microstrip line the 10, the 11 microstrip line 11 among Fig. 1.
Resonator with high selectivity dual band pass filter of independent adjustable passband is modes that a kind of hybrid electromagnetic is coupled with the coupled modes that the port feed line adopts.As shown in Figure 1; The coupled structure on top is made up of the 4th microstrip line 4, the 5th microstrip line 5, the 6th microstrip line 6, the 7th microstrip line 7, the 8th microstrip line 8, the 9th microstrip line 9, and the coupled structure of lower part is made up of the tenth microstrip line the 10, the 11 microstrip line the 11, the 12 microstrip line the 12, the 13 microstrip line the 13, the 14 microstrip line 14.Top adopts the access type coupled structure as the feed structure corresponding to the lower passband resonator.This is because adopt the access type structure can effectively strengthen the coupling of resonator and feed line.The quality factor q of lower passband
eMainly insert the live width decision of position, the 4th microstrip line 4 and the 7th microstrip line 7 of the 4th microstrip line 4 by the slit between the 4th microstrip line 4 and the 7th microstrip line 7, the 7th microstrip line 7.Coupling coefficient between top first resonator and second resonator then is the length decision by between the two gap width and the 6th microstrip line 6.The lower part is corresponding to the upper passband part of filter characteristic.The quality factor of upper passband are mainly by the length of spacing, the 13 microstrip line 13 and the 14 microstrip line 14 between the 13 microstrip line 13 and the tenth microstrip line 10.Coupling coefficient between the 3rd resonator and the 4th resonator is the length decision by between the two gap width and the 11 microstrip line 11.As shown in Figure 2, J '
0,1, J '
1,2, J '
2,3, J "
0,1, J "
1,2, J "
2,3The admittance inversion converter of representing first port and first resonator, first resonator and second resonator, second resonator and second port, first port and the 3rd resonator, the 3rd resonator and the 4th resonator, the 4th resonator and second port respectively; G representes the characteristic admittance of input/output port; Z
CouplingThe impedance coupling matrix of expression filter; L '
1, L '
2, L '
3, L '
4The equivalent inductance of representing first resonator, second resonator, the 3rd resonator, the 4th resonator respectively; C '
1, C '
2, C '
3, C '
4The equivalent capacity of representing first resonator, second resonator, the 3rd resonator, the 4th resonator respectively; What the utility model adopted is the feed structure of parallel connection, so the quality factor q e of two passbands and coupling coefficient k are separate up and down.In addition, the utility model adopts pseudo-interdigital structure to produce transmission zero.And the stiffness of coupling of pseudo-interdigital structure is by the number of the 15 microstrip line 15, length and the gap width decision separately.
Embodiment
High selectivity dual band pass Filter Structures with independent adjustable passband is as shown in Figure 1, and relevant dimensions is illustrated in fig. 4 shown below.The thickness of medium substrate is 0.81mm, and relative dielectric constant is 3.38, and loss angle tangent is 0.0027.Resonator adopts serpentine configuration can effectively reduce the size of filter.First variable capacitance diode 17, second variable capacitance diode 19, the 3rd variable capacitance diode 18, the 4th variable capacitance diode 20 adopt the 1sv277 of Toshiba; The negative pole of first variable capacitance diode 17 connects microstrip line one end, and the other end passes the intermediate layer medium substrate through electric capacity metallization via hole links to each other with the lower floor grounded metal.As shown in Figure 4, each dimension of microstrip line parameter of filter is following: the length of first microstrip line 1 is L
5=2.6 ± 0.2mm, the length of second microstrip line 2 is L
4=12.4 ± 0.3mm, the length of the 3rd microstrip line 3 is L
3=3.0 ± 0.1mm, the length of the 4th microstrip line 4 is L
2=13.6 ± 0.2mm, the length of the 5th microstrip line 5 is L
1=9.1 ± 0.4mm, the length of the 6th microstrip line 6 is L
1+ W
1+ W
2+ g
2=14.1 ± 0.3mm, the coupling spacing between resonator and the port feed line is g
2=g
4=0.2 ± 0.05mm, the width of first microstrip line 1, second microstrip line 2, the 3rd microstrip line 3, the 4th microstrip line 4, the 5th microstrip line 5 and the 6th microstrip line 6 is W
1=0.7 ± 0.1mm, the width of the 7th microstrip line 7, the 8th microstrip line 8 and the 9th microstrip line 9 is W
2=0.9mm, the width of the 16 microstrip line 16 are W
5=1.84mm, the characteristic impedance of the 16 microstrip line 16 is 50 Ω.The length of the tenth microstrip line 10, the 11 microstrip line 11 is respectively L
9=10.5 ± 0.5mm and L
8+ W
4+ W
6+ g
4=7.0 ± 0.4mm.The width of the tenth microstrip line 10, the 11 microstrip line 11 is W
6=0.7 ± 0.1mm, the width of the 12 microstrip line the 12, the 13 microstrip line 13, the 14 microstrip line 14 is W
4=0.3 ± 0.1mm.Gap between two resonators is g
1=g
5=0.3 ± 0.1mm.The length of the 15 microstrip line 15 is L
7=1.8 ± 0.2mm, the gap between each bar microstrip line is g
3=0.2 ± 0.05mm.Select these microstrip lines length and width separately, to obtain transmission characteristic and out-of band rejection characteristic in required I/O impedance operator, the frequency band.Fig. 5 a and Fig. 5 b be respectively according to above-mentioned parameter design the result of adjustable double band pass filter lower passband and the upper passband centre frequency emulation when changing; Transverse axis in the defeated performance diagram is represented frequency, and the longitudinal axis is represented transmission characteristic S
21, S
11Dotted line is S
11Simulation result, solid line are S
21Simulation result.Curve a among Fig. 5 a
1, b
1, c
1The centre frequency of representing lower passband respectively is respectively 570MHz, 630MHz, 690MHz and upper passband centre frequency transmission characteristic S when being 1.3GHz
21Simulation curve, curve a
2, b
2, c
2The centre frequency of representing lower passband respectively is respectively 570MHz, 630MHz, 690MHz and upper passband centre frequency transmission characteristic S when being 1.3GHz
11Simulation curve.Curve a among Fig. 5 b
1, b
1, c
1The centre frequency of representing upper passband respectively is respectively 1.156GHz, 1.24GHz, 1.336GHz and lower passband centre frequency transmission characteristic S when being 604MHz
21Simulation curve, curve a
2, b
2, c
2The centre frequency of representing upper passband respectively is respectively 1.156GHz, 1.24GHz, 1.336GHz and lower passband centre frequency transmission characteristic S when being 604MHz
11Simulation curve.Fig. 6 a and Fig. 6 b be respectively according to above-mentioned parameter design adjustable double band pass filter lower passband and the upper passband centre frequency actual measured results when changing; Transverse axis in the defeated performance diagram is represented frequency, and the longitudinal axis is represented transmission characteristic S
21, S
11Dotted line is S
11Actual measured results, solid line are S
21Actual measured results.Curve a among Fig. 6 a
1, b
1, c
1The centre frequency of representing lower passband respectively is respectively 570MHz, 630MHz, 690MHz and upper passband centre frequency transmission characteristic S when being 1.3GHz
21Actual measurement profile, curve a
2, b
2, c
2The centre frequency of representing lower passband respectively is respectively 570MHz, 630MHz, 690MHz and upper passband centre frequency transmission characteristic S when being 1.3GHz
11Actual measurement profile.Curve a among Fig. 6 b
1, b
1, c
1The centre frequency of representing upper passband respectively is respectively 1.156GHz, 1.24GHz, 1.336GHz and lower passband centre frequency transmission characteristic S when being 604MHz
21Actual measurement profile, curve a
2, b
2, c
2The centre frequency of representing upper passband respectively is respectively 1.156GHz, 1.24GHz, 1.336GHz and lower passband centre frequency transmission characteristic S when being 604MHz
11Actual measurement profile.Test result and simulation result basically identical, emulation is to use the commercial electromagnetism ADS of simulation software and the E5071C network analyzer of Agilent company to accomplish respectively with test.Visible by test result, the centre frequency of lower passband can be regulated in the 570-690MHz scope, and the centre frequency of upper passband can be regulated in the 1.156-1.336GHz scope; Transfer curve among Fig. 6 a is when the centre frequency of lower passband is respectively 570MHz, 630MHz, 690MHz and upper passband centre frequency for 1.3GHz, to record, with band pass filter S commonly used
11-3dB suppresses level as standard, and the bandwidth at-3dB place is respectively 40MHz, 52MHz, 60MHz; This shows, when lower passband changes-bandwidth at 3dB place is 50 ± 10MHz.Transfer curve among Fig. 6 b is when the centre frequency of upper passband is respectively 1.156GHz, 1.24GHz, 1.336GHz and lower passband centre frequency for 604MHz, to record, with band pass filter S commonly used
11-3dB suppresses level as standard, and the bandwidth at-3dB place is respectively 67MHz, 78MHz, 82MHz; This shows, when upper passband changes-bandwidth at 3dB place is 70 ± 10MHz.The test result explanation, when no matter being lower passband or upper passband variation, another passband is unaffected, has realized the target of dual band pass independent tuning.
Emulation and the measured result of embodiment show that when the centre frequency of the arbitrary passband in two passbands was tuning, the transmission characteristic of another passband among the embodiment remained unchanged basically, had realized the target of independent tuning.
The above is merely the preferred embodiments of the utility model; Not in order to restriction the utility model; All within the spirit and principle of the utility model, any modification of being done, be equal to replacement, improvement etc., all should be included within the protection range of the utility model.
Claims (7)
1. have the high selectivity dual band pass filter of independent adjustable passband, comprise upper strata microstrip structure, intermediate layer medium substrate and lower floor's grounding plate; The upper strata microstrip structure is attached to intermediate layer medium substrate upper surface, and lower floor's grounding plate is attached to intermediate layer medium substrate lower surface; It is characterized in that: the upper strata microstrip structure comprises port feed line, port microstrip line and four resonators; Four resonators all are the quarter-wave resonance devices; Four resonators are arranged into symmetrical structure; Two resonator structures that are positioned at the top are identical, and two resonator structures that are positioned at the below are identical, the port microstrip line of filter above two resonators and below two resonators between; Two resonators that are positioned at the top directly link to each other and parallel coupling with the port feed line, are positioned at two resonators and the parallel coupling of port feed line of below.
2. according to the said high selectivity dual band pass filter of claim 1 with independent adjustable passband; It is characterized in that being positioned at upper left first resonator and comprise first variable capacitance diode, coupled microstrip line part and non-coupled microstrip line part; Wherein the coupled microstrip line part is connected in sequence by the 4th microstrip line, the 5th microstrip line and the 6th microstrip line; Non-coupled microstrip line partly comprises first microstrip line, second microstrip line and the 3rd microstrip line; One end of first microstrip line links to each other with the negative pole of first variable capacitance diode; The positive pole of first variable capacitance diode links to each other with the lower floor grounded metal through the metallization via hole that passes the intermediate layer medium substrate through an electric capacity; First microstrip line, second microstrip line, the 3rd microstrip line, the 4th microstrip line, the 5th microstrip line and the 6th microstrip line are connected in order, and the metallization via hole that the 6th microstrip line end passes the intermediate layer medium substrate links to each other with the lower floor grounded metal; The 3rd resonator that is positioned at the lower left comprises the 3rd variable capacitance diode and coupled microstrip line part; Wherein the coupled microstrip line part is connected in sequence by the tenth microstrip line, the 11 microstrip line; One end of the tenth microstrip line links to each other with the negative pole of the 3rd variable capacitance diode; The positive pole of the 3rd variable capacitance diode links to each other with the lower floor grounded metal through the metallization via hole that passes the intermediate layer medium substrate through an electric capacity, and the tenth microstrip line other end links to each other with an end of the 11 microstrip line; The metallization via hole that the other end of the 11 microstrip line passes the intermediate layer medium substrate links to each other with the lower floor grounded metal.
3. according to the said high selectivity dual band pass filter with independent adjustable passband of claim 2, the electrical length L+ Δ L that it is characterized in that being positioned at upper left resonator is 1/4th of the corresponding wavelength X of the low resonant frequency f of said dual band pass filter; Wherein, L is actual microstrip line length, and Δ L is first variable capacitance diode equivalence microstrip line length of upper left first resonator; Actual microstrip line length L is the length sum of first microstrip line, second microstrip line, the 3rd microstrip line, the 4th microstrip line, the 5th microstrip line and the 6th microstrip line; Length between the coupled zone equals the 4th microstrip line, the length summation of the 5th microstrip line and the 6th microstrip line; The electrical length L '+Δ L ' that is positioned at the resonator of lower left for the corresponding wavelength X of the high resonance frequency f ' of said dual band pass filter ' 1/4th; Wherein L ' is actual microstrip line length, and Δ L ' is the 3rd variable capacitance diode equivalence microstrip line length of the resonator of lower left; Actual microstrip line length L ' be the length sum of the tenth microstrip line, the 11 microstrip line; Length between the coupled zone equals the length summation of the tenth microstrip line, the 11 microstrip line.
4. according to the said high selectivity dual band pass filter of claim 2 with independent adjustable passband; It is characterized in that the coupled microstrip line part that is positioned at upper left resonator is in turn connected into n shape structure by the 4th microstrip line, the 5th microstrip line and the 6th microstrip line, the coupled microstrip line part that is positioned at the resonator of lower left is in turn connected into L shaped structure by the tenth microstrip line, the 11 microstrip line.
5. according to the said high selectivity dual band pass filter of claim 2 with independent adjustable passband; It is characterized in that said port feed line comprises coupling feed line part and non-coupling feed line part; The feed line that wherein is coupled partly comprises two parts up and down, and top is connected and composed by the 7th microstrip line, the 8th microstrip line and the 9th microstrip line successively; The 7th microstrip line is connected with the 4th microstrip line and realizes stronger coupling between the feed line resonator; The lower part is connected and composed by the 13 microstrip line and the 14 microstrip line successively; The non-coupling feed line part of port feed line is made up of the 12 microstrip line; Be provided with the electromagnetic coupled gap that width is 0.2 ± 0.05mm between the port feed line coupling feed line part resonator coupled microstrip line part; The port microstrip line comprises the 16 microstrip line; First resonator, second resonator are positioned at the 16 microstrip line top, and the 3rd resonator, the 4th resonator are positioned at the 16 microstrip line below.
6. according to the said high selectivity dual band pass filter of claim 5 with independent adjustable passband; The top that it is characterized in that the coupling feed line of port feed line connects and composes n shape structure successively by the 7th microstrip line, the 8th microstrip line and the 9th microstrip line, is positioned at the inboard of the first resonator coupled microstrip line part n shape structure; The 7th microstrip line, the 8th microstrip line and the 9th little band are parallel with the 6th microstrip line with the 4th microstrip line, the 5th microstrip line respectively; The lower part of the coupling feed line of port feed line connects and composes L shaped structure successively by the 13 microstrip line and the 14 microstrip line, is positioned at the inboard of resonator coupled microstrip line partial L shape structure; The 13 microstrip line is parallel with the 11 microstrip line with the tenth microstrip line respectively with the 14 microstrip line.
7. the high selectivity dual band pass filter with independent adjustable passband according to claim 6 is characterized in that the length of first microstrip line is 2.6 ± 0.2mm; The length of second microstrip line is 12.4 ± 0.3mm; The length of the 3rd microstrip line is 3.0 ± 0.1mm, and the length of the 4th microstrip line is 13.6 ± 0.2mm, and the length of the 5th microstrip line is 9.1 ± 0.4mm; The length of the 6th microstrip line is 14.1 ± 0.3mm; Coupling spacing between said four resonators and the port feed line is 0.2 ± 0.05mm, and the width of first microstrip line, second microstrip line, the 3rd microstrip line, the 4th microstrip line, the 5th microstrip line and the 6th microstrip line is 0.7 ± 0.1mm, and the width of the 7th microstrip line, the 8th microstrip line and the 9th microstrip line is 0.9mm; The width of the 16 microstrip line is 1.84mm, and the characteristic impedance of the 16 microstrip line is 50 Ω; The length of the tenth microstrip line, the 11 microstrip line is respectively 10.5 ± 0.5mm and 7.0 ± 0.4mm, and the gap of the tenth microstrip line and the 13 microstrip line is 0.2 ± 0.05mm; Gap between first resonator, second resonator and the 3rd resonator, the 4th resonator is 0.4mm; The length of the 15 microstrip line is 1.8 ± 0.2mm, and the spacing between each bar microstrip line is 0.2 ± 0.05mm; The variable capacitance diode of first resonator, second resonator is provided with identical bias voltage, and the variable capacitance diode of the 3rd resonator, the 4th resonator is provided with identical bias voltage.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011204630933U CN202363565U (en) | 2011-11-18 | 2011-11-18 | High-selectivity double-band-pass filter with independently tunable passbands |
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| CN2011204630933U CN202363565U (en) | 2011-11-18 | 2011-11-18 | High-selectivity double-band-pass filter with independently tunable passbands |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102403557A (en) * | 2011-11-18 | 2012-04-04 | 华南理工大学 | High-selectivity double band-pass filter with independent adjustable passband |
| 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 |
-
2011
- 2011-11-18 CN CN2011204630933U patent/CN202363565U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102403557A (en) * | 2011-11-18 | 2012-04-04 | 华南理工大学 | High-selectivity double band-pass filter with independent adjustable passband |
| CN102403557B (en) * | 2011-11-18 | 2014-02-12 | 华南理工大学 | High-selectivity double band-pass filter with independent adjustable passband |
| 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 |
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