CN202364184U - Balanced radio frequency electric adjustment band pass filter with constant absolute bandwidth - Google Patents
Balanced radio frequency electric adjustment band pass filter with constant absolute bandwidth Download PDFInfo
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- CN202364184U CN202364184U CN2011201771732U CN201120177173U CN202364184U CN 202364184 U CN202364184 U CN 202364184U CN 2011201771732 U CN2011201771732 U CN 2011201771732U CN 201120177173 U CN201120177173 U CN 201120177173U CN 202364184 U CN202364184 U CN 202364184U
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Abstract
The utility model discloses a balanced radio frequency electric adjustment band pass filter with constant absolute bandwidth. The band pass filter is composed of an upper microstrip structure, a central medium substrate and a lower grounding metal. A balanced circuit is adopted by the upper microstrip structure which comprises four half-wavelength resonators, two input feed networks, two output feed networks, two input ports and two output ports. Each four half-wavelength resonator is composed of a microstrip line and a varactor diode with two ends connected. Capacitance is loaded in both the first half-wavelength resonator and the third half-wavelength resonator. The second half-wavelength resonator and the fourth half-wavelength resonator are bent to be arranged in a symmetrical manner. The whole filter is symmetrical in terms of a mirror image. The balanced radio frequency electric adjustment band pass filter allows bandwidth to be absolutely constant for central frequency tuning, enables common mode interference to be inhibited, and can be used for a reconfigurable radio frequency front terminal of wireless communication.
Description
Technical field
The utility model relates to the adjustable balanced type radio frequency electrically adjusted band-pass filter of centre frequency, is specifically related to a kind of balanced type radio frequency electrically adjusted band-pass filter with constant absolute bandwidth that can be applicable in multiband, broadband and the restructural radio-frequency front-end system.
Background technology
Modern ULTRA-WIDEBAND RADAR and radio communication require to adopt high performance restructural radio-frequency front-end.For example in the cognitive radio system, in order to make full use of and to merge various wireless channel and standard, radio-frequency front-end need be operated on the different frequencies, and this just needs the tunable restructural radio-frequency front-end of centre frequency.Radio frequency electrically adjusted band-pass filter is the important component part of restructural radio-frequency front-end, therefore comes into one's own day by day.Aspect this, some research reports have been arranged at present, multiple different tuning device also is used, for example semiconductor variable capacitance diode, radio-frequency micro electromechanical system (RF MEMS) capacitance tube and ferroelectric thin-flim materials varactor etc.
No matter adopt which kind of tuning device, the problem that radio frequency electrically adjusted band-pass filter faced mainly comprises:
(1) for example when the centre frequency of tuning passband; The absolute bandwidth of passband also can change thereupon; And the absolute bandwidth of wireless channel is invariable in plurality of applications, so we need make the absolute bandwidth of passband keep invariable in tuning centre frequency.
(2) interference of system's ambient noise.The existence of ambient noise causes the decreased performance of filter, thereby has influence on the overall performance of radio-frequency front-end.Therefore must take some to suppress the method for ambient noise.
To the constant problem of the tuning Time Bandwidth of centre frequency, certain methods has been proposed at present.According to " M. Sanchez-Renedo, R. Gomez-Garcia, J. I. Alonso, and C. Briso-Rodriguez,
Tunable combline filter with continuous control of center frequency and bandwidth, IEEE Trans. Microw. Theory Tech., vol. 53, no. 1, pp. 191-199, Jan, 2005. " and the analysis that provided can know, control coupling coefficient through between resonator, inserting medium, thereby it is constant to satisfy bandwidth.According to " S. J. Park, and G. M. Rebeiz,
Low-loss two-pole tunable filters with three different predefined bandwidth characteristics, IEEE Trans. Microw. Theory Tech., vol. 56; No. 5, pp. 1137-1148, May; 2008. " analysis that provided can know, adopts independently electric coupling and magnetic coupling mechanism to control the variation of coupling coefficient, can realize specific bandwidth characteristic.According to " M. A. El-Tanani, and G. M. Rebeiz,
High-Performance 1.5-2.5-GHz RF-MEMS Tunable Filters for Wireless Applications, IEEE Trans. Microw. Theory Tech., vol. 58, no. 6, pp. 1629-1637, Jun, 2010. " and the analysis that provided can know that it is constant to adopt electromagnetism hybrid coupled mechanism can satisfy bandwidth equally.Yet the top method that proposes all is the single port circuit, and is powerless basically for the inhibition of ambient noise.
The balanced structure circuit has the better inhibited effect to ambient noise, so is used widely in the balancing circuitry modern communication system.Current most research mainly concentrates on stopband expansion, common mode inhibition, widens passband or uses differential-mode response to obtain double frequency-band.According to " J. Shi, and Q. Xue,
Balanced Bandpass Filters Using Center-Loaded Half-Wavelength Resonators, IEEE Trans. Microw. Theory Tech., vol. 58, no. 4, pp. 970-977, Apr, 2010. " and the analysis that provided can know that the mode of middle loading resistor can absorb common-mode signal.But balanced type Design of Filter recited above all is that frequency is nonadjustable.Up to the present also having no research report is about having the radio frequency electrically adjusted filter of balanced type of absolute bandwidth control and common mode inhibition characteristic.
The utility model content
In order to reach constant absolute bandwidth; And this type of ambient noise common-mode signal suppressed; The utility model provides the radio frequency electrically adjusted band-pass filter of the balanced type with constant absolute bandwidth; This balanced type band pass filter when not only centre frequency is tuning absolute bandwidth constant, and common-mode signal had the good restraining effect.
The utility model solves the technical scheme that its technical problem adopted:
Balanced type radio frequency electrically adjusted band-pass filter with constant absolute bandwidth comprises the microstrip structure on upper strata, the grounded metal of intermediate layer medium substrate and lower floor; The upper strata microstrip structure is attached to intermediate layer dielectric-slab upper surface, and intermediate layer dielectric-slab lower surface is a grounded metal; The upper strata microstrip structure comprises four half-wave resonator, two input feeding networks, two outputs feeding network, two input ports and two output ports; Two input ports are connected with two input feeding networks respectively; Two output ports are connected with two output feeding networks respectively; Two input feeding networks join with first half-wave resonator respectively with the tap line mode; First half-wave resonator is joined with second half-wave resonator and the 4th half-wave resonator respectively again; Second half-wave resonator and the 4th half-wave resonator are coupled with the 3rd half-wave resonator respectively again; The 3rd half-wave resonator is joined with two output feeding networks respectively with the tap line mode again, and the centre of first half-wave resonator and the 3rd half-wave resonator all is loaded with the different big or small electric capacity that are used to absorb common-mode signal, and all there is variable capacitance diode at the two ends of above-mentioned all half-wave resonator.
In the above-mentioned balanced type radio frequency electrically adjusted band-pass filter with constant absolute bandwidth; Said first half-wave resonator is connected and composed by first variable capacitance diode, first microstrip line, second microstrip line, the 3rd microstrip line, the 4th microstrip line and second variable capacitance diode in order; The anode of first variable capacitance diode and second variable capacitance diode all passes the intermediate layer medium substrate and links to each other with the lower floor grounded metal, and the 3rd half-wave resonator is identical with the first half-wave resonator structure; Second half-wave resonator is connected and composed by the 3rd variable capacitance diode, the 5th microstrip line, the 6th microstrip line, the 7th microstrip line, the 4th variable capacitance diode in order; The anode of the 3rd variable capacitance diode and the 4th variable capacitance diode all passes the intermediate layer medium substrate and links to each other with the lower floor grounded metal, and the 4th half-wave resonator is identical with the second half-wave resonator structure and between first half-wave resonator and the 3rd half-wave resonator; The 5th microstrip line of second half-wave resonator and second microstrip line of first half-wave resonator laterally arrange and constitute the interstage coupling structure; The 7th microstrip line of second half-wave resonator and the tenth microstrip line of the 3rd half-wave resonator laterally arrange and constitute the interstage coupling structure; About above-mentioned four half-wave resonator are arranged into, equal symmetrical structure up and down; Two first input feeding networks of importing in the feeding network are connected and composed by first electric capacity, the 8th microstrip line in order, and the 8th microstrip line other end is received on second microstrip line of first half-wave resonator with the tap line mode; The structure of the second input feeding network is identical with the first input feeding network; First input end mouth in two input ports is made up of the 9th microstrip line; The 9th microstrip line is connected with the first electric capacity top of the first input feeding network; Second input port is identical with the first input end mouth structure; Two input feeding networks are identical with two output feeding network structures, and two input ports are identical with two output port structures; About two input feeding networks, two outputs feeding networks, two input ports, two output ports and above-mentioned four half-wave resonator are arranged into together, equal symmetrical structure up and down.
In the above-mentioned balanced type radio frequency electrically adjusted band-pass filter with constant absolute bandwidth, the said electric capacity other end all passes the intermediate layer medium substrate and links to each other with the lower floor grounded metal.
Described balanced type radio frequency electrically adjusted band-pass filter with constant absolute bandwidth; When first input end mouth and second input port input difference mode signal, whole filter forms an electric divider wall on the linear position at the mid point place of first half-wave resonator and the 3rd half-wave resonator.Because the coupling of this structure between resonator mainly is electric coupling; First half-wave resonator and the 3rd half-wave resonator do not have electric current in the centre position; Being connected on the said electric capacity that loads in the middle of first half-wave resonator and the 3rd half-wave resonator can ignore; Therefore under the differential mode excitation, first half-wave resonator is two identical quarter-wave resonators with the 3rd half-wave resonator equivalence, and while and the coupling of second half-wave resonator form bandpass filter structures; When first input end mouth and second input port input common-mode signal, whole filter forms a magnetic divider wall on the linear position at the mid point place of first half-wave resonator and the 3rd half-wave resonator.First half-wave resonator and the 3rd half-wave resonator are equipped with current flowing in interposition, and being connected on the said electric capacity that loads in the middle of first half-wave resonator and the 3rd half-wave resonator has current flowing.The said electric capacity that two quarter-wave resonators of first half-wave resonator and the equivalence of the 3rd half-wave resonator load in the middle of need considering.Because the said electric capacity that loads in the middle of on first half-wave resonator and the 3rd half-wave resonator is different, the resonance frequency of two quarter-wave resonance devices of real work equivalence is different, makes common-mode signal not pass through, and reaches the effect of inhibition.Said whole input and output feeding network adopts the tap line feeding classification, can obtain better external sort factor; Adopt electromagnetism hybrid coupled mechanism can satisfy constant absolute bandwidth at coupling regime.
For further realizing the utility model purpose, the said first microstrip line length with balanced type radio frequency electrically adjusted band-pass filter of constant absolute bandwidth is 10.2mm, and width is 0.8mm; The second microstrip line length is 18.7mm, and the 5th microstrip line length is 24.1mm, and width is 0.8mm; The 6th microstrip line length is 10.4mm, and the 8th microstrip line length is 3.3mm, and width is 0.6mm; First capacitance size is 7pF; The said capacitance size that loads in the middle of first half-wave resonator is 20pF, and the said capacitance size that loads in the middle of the 3rd half-wave resonator is 7pF, and the distance between second microstrip line and the 5th microstrip line is 0.6mm.
Compared with prior art, the utility model adopts novel balanced structure and half-wave resonator interstage coupling structure, and the absolute bandwidth bandwidth kept electrically adjusted band-pass filter constant and ability good restraining common mode interference signal when centre frequency was tuning.Have following advantage and effect generally:
(1) owing to use the balanced structure design, this band pass filter then has good inhibitory effect for difference mode signal ability operate as normal for common-mode signal, and therefore interference has immunologic function for this type of ambient noise.The common mode inhibition level of surveying among the embodiment all surpasses-23dB.
(2) through setting to input feeding network and interstage coupling mode, can be implemented in centre frequency relative bandwidth or absolute bandwidth constant when tuning, can satisfy the different application demand.
Description of drawings
Fig. 1 be have constant definitely to the schematic diagram of the balanced type radio frequency electrically adjusted band-pass filter ABW of bandwidth;
Fig. 2 is an ABW differential mode equivalent electric circuit;
Fig. 3 a is the equivalent quarter-wave resonance device under the ABW differential mode situation;
Fig. 3 b is the equivalent half-wave resonator under the ABW differential mode situation;
Fig. 4 is the relation that the quarter-wave resonance device is thanked vibration frequency, capacitance and microstrip line length among Fig. 3 a;
Fig. 5 is the relation that half-wave resonator is thanked vibration frequency, capacitance and microstrip line length among Fig. 3 b;
Fig. 6 is the ABW common mode equivalent circuit;
Fig. 7 is the equivalent quarter-wave resonance device of first resonator under the ABW common mode situation;
Fig. 8 a is the differential mode transfer curve of ABW;
Fig. 8 b is the differential mode return loss plot of ABW;
Fig. 8 c is the common mode transmission characteristic curve of ABW.
Specific embodiments
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 balanced type radio frequency electrically adjusted band-pass filter of constant absolute bandwidth, it is characterized in that comprising the microstrip structure on upper strata, the grounded metal of intermediate layer medium substrate and lower floor; The upper strata microstrip structure is attached to intermediate layer dielectric-slab upper surface, and intermediate layer dielectric-slab lower surface is a grounded metal; The upper strata microstrip structure comprises four half-wave resonator, two input feeding networks, two outputs feeding network, two input ports and two output ports; Two input ports are connected with two input feeding networks respectively; Two output ports are connected with two output feeding networks respectively; Two input feeding networks join with first half-wave resonator respectively with the tap line mode and (promptly are not connected with the two ends of first half-wave resonator; And be connected) with position between the two ends; First half-wave resonator is joined with second half-wave resonator and the 4th half-wave resonator respectively again; Second half-wave resonator and the 4th half-wave resonator are coupled with the 3rd half-wave resonator respectively again, and the 3rd half-wave resonator is joined with two output feeding networks respectively with the tap line mode again, and the centre of first half-wave resonator and the 3rd half-wave resonator all is loaded with the different big or small electric capacity that are used to absorb common-mode signal; All there is variable capacitance diode at the two ends of above-mentioned all half-wave resonator.
Said first half-wave resonator is connected and composed by first variable capacitance diode 1, first microstrip line 2, second microstrip line 3, the 3rd microstrip line 4, the 4th microstrip line 5 and second variable capacitance diode 6 in order; The anode of first variable capacitance diode 1 and second variable capacitance diode 6 all passes the intermediate layer medium substrate and links to each other with the lower floor grounded metal, and the 3rd half-wave resonator is identical with the first half-wave resonator structure; Second half-wave resonator is connected and composed by the 3rd variable capacitance diode 7, the 5th microstrip line 8, the 6th microstrip line 9, the 7th microstrip line 10, the 4th variable capacitance diode 11 in order; The anode of the 3rd variable capacitance diode 7 and the 4th variable capacitance diode 11 all passes the intermediate layer medium substrate and links to each other with the lower floor grounded metal, and the 4th half-wave resonator is identical with the second half-wave resonator structure and between first half-wave resonator and the 3rd half-wave resonator; The 5th microstrip line 8 of second half-wave resonator and second microstrip line 3 of first half-wave resonator laterally arrange and constitute the interstage coupling structure; The 7th microstrip line 10 of second half-wave resonator and the tenth microstrip line 12 of the 3rd half-wave resonator laterally arrange and constitute the interstage coupling structure; About above-mentioned four half-wave resonator are arranged into, equal symmetrical structure up and down; Two inputs first in feeding network input feeding network 17 is connected and composed by first electric capacity 15, the 8th microstrip line 16 in order, and the 8th microstrip line 16 other ends are received on second microstrip line 3 of first half-wave resonator with the tap line mode; The structure of the second input feeding network 18 is identical with the first input feeding network 17; First input end mouth IN in two input ports is made up of the 9th microstrip line 21; The 9th microstrip line 21 is connected with first electric capacity, 15 tops of the first input feeding network 17; The second input port IN ' is identical with first input end mouth IN structure; Two input feeding networks are identical with two output feeding network structures, and two input ports are identical with two output port structures; About two input feeding networks, two outputs feeding networks, two input ports, two output ports and above-mentioned four half-wave resonator are arranged into together, equal symmetrical structure up and down.The centre of first half-wave resonator and the 3rd half-wave resonator all is loaded with second electric capacity 13 and the 3rd electric capacity 14 of the different sizes that are used to absorb common-mode signal, and said second electric capacity 13 and the 3rd electric capacity 14 all have an end to pass the intermediate layer medium substrate to link to each other with the lower floor grounded metal;
The characteristic impedance of the transmission line of two input ports and two output ports all is 50 Ω.
The parameters of adjustment filter makes filter on total, reach balance.When first input end mouth IN and the second input port IN ' input difference mode signal, whole filter forms an electric divider wall on the linear position at the mid point place of first half-wave resonator and the 3rd half-wave resonator.Because the coupling of this structure between resonator mainly is electric coupling; First half-wave resonator and the 3rd half-wave resonator do not have electric current in the centre position; Being connected on said second electric capacity 13 and the 3rd electric capacity 14 that load in the middle of first half-wave resonator and the 3rd half-wave resonator can ignore; Therefore under the differential mode excitation; First half-wave resonator and the 3rd half-wave resonator equivalence are two quarter-wave resonators, and while and the coupling of second half-wave resonator form bandpass filter structures; This moment, the equivalent structure of filter was as shown in Figure 2.Fig. 3 a and 3b have provided the quarter-wave resonance device and second half-wave resonator of equivalence under the differential mode situation.According to " A. R. Brown, and G. M. Rebeiz,
A varactor-tuned RF filter, IEEE Trans. Microw. Theory Tech., vol. 48, and no. 7; Pp. 1157-1160, Jul, 2000. " analysis that provided can know; in Fig. 3 a, when quarter-wave resonance device resonance, see admittance Y in the past from quarter-wave resonance device left end
Dd_in1Imaginary part equal zero, for a given voltage, load the resonance frequency of the whole resonator of variable capacitance diode:
Wherein
is the characteristic admittance of resonator;
is the electrical length of first microstrip line 6; C is the capacitance that variable capacitance diode is depressed in different electric; In Fig. 4, shown the resonance frequency of quarter-wave resonance device among Fig. 3 a, the capacitance C of variable capacitance diode and the relation of microstrip line length, can find out the increase along with electric capacity, the resonance frequency of resonator descends; Along with shortening of microstrip line length, scalable is interval to become big; For second half-wave resonator, resonance frequency is equally:
Wherein
is the characteristic admittance of resonator;
is the electrical length of half-wave resonator; C is the capacitance that variable capacitance diode is depressed in different electric; The resonance frequency of second half-wave resonator among Fig. 3 b, the capacitance C of variable capacitance diode and the relation of microstrip line length in Fig. 5, have been shown; Can find out at the relation property of length 10-18mm scope interior resonance frequency and capacitance similar with the relation property of quarter-wave resonance device in length 6-8mm; During as
, under the identical voltage
; So two resonant frequencies can mate when voltage is identical, filter can operate as normal.
When first input end mouth and second input port input common-mode signal, whole filter forms a magnetic divider wall on the linear position at the mid point place of first half-wave resonator and the 3rd half-wave resonator.First half-wave resonator and the 3rd half-wave resonator are equipped with current flowing in interposition, and being connected on the said electric capacity that loads in the middle of first half-wave resonator and the 3rd half-wave resonator has current flowing.The said electric capacity that two quarter-wave resonators of first half-wave resonator and the equivalence of the 3rd half-wave resonator load in the middle of need considering.Real work equivalence filter structure during common-mode signal is as shown in Figure 6.Fig. 7 has provided the quarter-wave resonator of equivalence, and resonance frequency is:
Shown in figure, Y
1It is the characteristic admittance of microstrip line; θ
1The electrical length of microstrip line; C is the capacitance that variable capacitance diode is depressed in different electric; C
2It is the capacitance of said loading capacitance.
Because said second electric capacity 13 that loads and the capacitance of the 3rd electric capacity 14 vary in size, make that the resonance frequency of these two resonators is different, signal can not pass through; Common-mode signal just has been suppressed.
Can find out that in Fig. 2 and Fig. 6 said filter adopts tap line mode feed.According to " R. J. Cameron, C. M. Kudsia, and R. R. Mansour,
Microwave Filters for Communication Systems:Fundamentals, Design, and Applications, New York:Wiley:John Wiley & Sons, Inc, 2007. " and the analysis that provided can know, for ABW, at certain constant absolute bandwidth; The actual external sort factor of filter
Increase along with the increase of frequency; So in the ABW structure, adopt the tap line feeding classification, more easily the controlling performance factor
In the mechanism of inter-stage employing electromagnetism hybrid coupled, like the coupling regime in the frame of broken lines among Fig. 2, there is the coupling of electric coupling and magnetic simultaneously, can realize that the interstage coupling coefficient k descends along with the increase of frequency.
Below among the embodiment, the ABW with the constant absolute bandwidth of 60MHz is produced on that relative dielectric constant is 10.2, thickness is that 0.63mm, fissipation factor are on 0.0023 the medium substrate.Variable capacitance diode is selected the silicon variable capacitance diode lsv277 of Toshiba for use.
Embodiment: balanced type radio frequency electrically adjusted band-pass filter with the constant absolute bandwidth of 60MHz
Balanced type radio frequency electrically adjusted band-pass filter structure with the constant absolute bandwidth of 60MHz is as shown in Figure 1.Concrete parameter is: first microstrip line, 2 length are 10.2mm, and width is 0.8mm, and second microstrip line, 3 length are 18.7mm; The 5th microstrip line 8 length are 24.1mm, and width is 0.8mm, and the 6th microstrip line 9 length are 10.4mm; The 8th microstrip line 16 length are 3.3mm; Width is 0.6mm, and first electric capacity, 15 sizes are 7pF, and said second electric capacity, 13 sizes that load in the middle of first half-wave resonator are 20pF; Said the 3rd electric capacity 14 sizes that load in the middle of the 3rd half-wave resonator are 7pF, and the distance between second microstrip line 3 and the 5th microstrip line 8 is 0.6mm.Fig. 8 has provided the result that the filter that utilizes above-mentioned parameter to design carries out emulation and actual measurement, and wherein emulation and actual measurement are to use the commercial electromagnetism ADS of simulation software and the E5071C network analyzer of Agilent company to accomplish respectively.Fig. 8 a is the transmission characteristic of emulation, calculating and the test when four special bias voltages under this filter differential mode working condition, and transverse axis is represented frequency, and the longitudinal axis is represented transmission characteristic | S
Dd21|.Fig. 8 b is depicted as the reflection characteristic of this filter, and transverse axis is represented frequency, and the longitudinal axis is represented return loss | S
Dd11|.Visible by Fig. 8 a and Fig. 8 b, the band connection frequency of filter can be transferred to 775MHz from 549MHz, has 34.1% relative adjustment scope.To all tuning states, the in-band insertion loss of measurement is between 3.5-4.2dB, and return loss all is lower than-10dB.Three dB bandwidth be 60
4MHz, substantially constant.Fig. 8 c has shown under the common mode working condition inhibition to common-mode noise, visiblely all is lower than-25dB in the 0.2-1.7GHz common mode inhibition.
The utility model is based on the balanced structure of mirror image symmetry, under differential mode and common-mode signal, has different equivalent electric circuits, has constant absolute bandwidth, and intermediate frequency is adjustable, in the frequency band of broad, suppresses common-mode noise.Bandwidth and passband waveform keep invariable in frequency tuning range.Through the parameter of adjusted design, can regulate bandwidth, promptly this structure can be used for realizing various bandwidth specifications.
The above is merely the preferred embodiments of the utility model, and is in order to restriction the utility model, not all within the spirit and principle of the utility model, any modification of being done, is equal to replacement, improvement etc., all should be included within the protection range of the utility model.
Claims (6)
1. the balanced type radio frequency electrically adjusted band-pass filter that has constant absolute bandwidth is characterized in that comprising the microstrip structure on upper strata, the grounded metal of intermediate layer medium substrate and lower floor; The upper strata microstrip structure is attached to intermediate layer dielectric-slab upper surface, and intermediate layer dielectric-slab lower surface is a grounded metal; The upper strata microstrip structure comprises four half-wave resonator, two input feeding networks, two outputs feeding network, two input ports and two output ports; Two input ports are connected with two input feeding networks respectively; Two output ports are connected with two output feeding networks respectively; First half-wave resonator is joined with two input feeding networks respectively with the tap line mode; First half-wave resonator is coupled with second half-wave resonator and the 4th half-wave resonator respectively again; Second half-wave resonator and the 4th half-wave resonator are coupled with the 3rd half-wave resonator respectively again; The 3rd half-wave resonator is joined with two output feeding networks respectively with the tap line mode again, and the centre of first half-wave resonator and the 3rd half-wave resonator all is loaded with the different big or small electric capacity that are used to absorb common-mode signal, and all there is variable capacitance diode at the two ends of above-mentioned all half-wave resonator.
2. the balanced type radio frequency electrically adjusted band-pass filter with constant absolute bandwidth according to claim 1; It is characterized in that said first half-wave resonator is connected and composed by first variable capacitance diode, first microstrip line, second microstrip line, the 3rd microstrip line, the 4th microstrip line and second variable capacitance diode in order; First microstrip line is perpendicular to second microstrip line; The 3rd microstrip line is perpendicular to the 4th microstrip line; The anode of first variable capacitance diode and second variable capacitance diode all passes the intermediate layer medium substrate and links to each other with the lower floor grounded metal, and the 3rd half-wave resonator is identical with the first half-wave resonator structure; Second half-wave resonator is connected and composed by the 3rd variable capacitance diode, the 5th microstrip line, the 6th microstrip line, the 7th microstrip line, the 4th variable capacitance diode in order; The anode of the 3rd variable capacitance diode and the 4th variable capacitance diode all passes the intermediate layer medium substrate and links to each other with the lower floor grounded metal; The 4th half-wave resonator is identical with the second half-wave resonator structure and between first half-wave resonator and the 3rd half-wave resonator, about above-mentioned four half-wave resonator are arranged into together, equal symmetrical structure up and down; Two first input feeding networks of importing in the feeding network are connected and composed by first electric capacity, the 8th microstrip line in order; One end of the 8th microstrip line is connected with first electric capacity, one end, and second microstrip line of first half-wave resonator is connected with the other end of tap line mode with the 8th microstrip line; The structure of the second input feeding network is identical with the first input feeding network; First input end mouth in two input ports is made up of the 9th microstrip line; The 9th microstrip line is connected with the other end of first electric capacity of the first input feeding network; Second input port is identical with the first input end mouth structure; Two input feeding networks are identical with two output feeding network structures, and two input ports are identical with two output port structures; About two input feeding networks, two outputs feeding networks, two input ports, two output ports and above-mentioned four half-wave resonator are arranged into together, equal symmetrical structure up and down.
3. the balanced type radio frequency electrically adjusted band-pass filter with constant relative bandwidth according to claim 2, it is characterized in that first half-wave resonator and the 3rd half-wave resonator in the middle of the other end of the said electric capacity that loads pass the intermediate layer medium substrate and link to each other with the lower floor grounded metal.
4. the balanced type radio frequency electrically adjusted band-pass filter with constant relative bandwidth according to claim 2, second microstrip line that it is characterized in that the 5th microstrip line and first half-wave resonator of second half-wave resonator laterally arranges and constitutes the interstage coupling structure; The 7th microstrip line of second half-wave resonator and the tenth microstrip line of the 3rd half-wave resonator laterally arrange and constitute the interstage coupling structure.
5. the balanced type radio frequency electrically adjusted band-pass filter with constant relative bandwidth according to claim 2, the characteristic impedance that it is characterized in that the transmission line of two input ports and two output ports all is 50 Ω.
6. according to each described radio frequency electrically adjusted filter of balanced type of claim 2～5, it is characterized in that the said first microstrip line length is 10.2mm with constant relative bandwidth; Width is 0.8mm, and the second microstrip line length is 18.7mm, and the 5th microstrip line length is 24.1mm; Width is 0.8mm, and the 6th microstrip line length is 10.4mm, and the 8th microstrip line length is 3.3mm; Width is 0.6mm, and first capacitance size is 7pF, and the said capacitance size that loads in the middle of first half-wave resonator is 20pF; The said capacitance size that loads in the middle of the 3rd half-wave resonator is 7pF, and the distance between second microstrip line and the 5th microstrip line is 0.6mm.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102324599A (en) * | 2011-05-27 | 2012-01-18 | 华南理工大学 | Balanced type radio frequency voltage tunable bandpass filter with constant absolute bandwidth |
| CN103943919A (en) * | 2014-04-23 | 2014-07-23 | 西南交通大学 | Constant-bandwidth tunable bandpass filter |
| CN116800219A (en) * | 2023-07-20 | 2023-09-22 | 南通至晟微电子技术有限公司 | Circuit structure for balancing frequency adjustable to single-ended filtering power divider |
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2011
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102324599A (en) * | 2011-05-27 | 2012-01-18 | 华南理工大学 | Balanced type radio frequency voltage tunable bandpass filter with constant absolute bandwidth |
| CN102324599B (en) * | 2011-05-27 | 2014-02-26 | 华南理工大学 | Balanced type radio frequency voltage tunable bandpass filter with constant absolute bandwidth |
| CN103943919A (en) * | 2014-04-23 | 2014-07-23 | 西南交通大学 | Constant-bandwidth tunable bandpass filter |
| CN103943919B (en) * | 2014-04-23 | 2016-06-01 | 西南交通大学 | The variable band-pass filter of a kind of constant bandwidth |
| CN116800219A (en) * | 2023-07-20 | 2023-09-22 | 南通至晟微电子技术有限公司 | Circuit structure for balancing frequency adjustable to single-ended filtering power divider |
| CN116800219B (en) * | 2023-07-20 | 2024-03-19 | 南通至晟微电子技术有限公司 | Frequency-adjustable balance to single-ended filtering power divider |
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