CN107425823A - A kind of ultra wide band bandpass filter - Google Patents
A kind of ultra wide band bandpass filter Download PDFInfo
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- CN107425823A CN107425823A CN201710594335.4A CN201710594335A CN107425823A CN 107425823 A CN107425823 A CN 107425823A CN 201710594335 A CN201710594335 A CN 201710594335A CN 107425823 A CN107425823 A CN 107425823A
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- 239000003990 capacitor Substances 0.000 claims description 49
- 238000001914 filtration Methods 0.000 claims description 37
- 238000003780 insertion Methods 0.000 abstract description 5
- 230000037431 insertion Effects 0.000 abstract description 5
- 238000004891 communication Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/0153—Electrical filters; Controlling thereof
- H03H7/0161—Bandpass filters
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
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- Filters And Equalizers (AREA)
Abstract
A kind of ultra wide band bandpass filter, can solve traditional ultra-wide band filter exponent number is too high and the technical problem of poor selectivity.Including input port, the first filter unit, the second filter unit, the 3rd filter unit, the 4th filter unit and output port, radio-frequency input signals is introduced by input port, input port connects the input of the first filter unit, the output end of first filter unit connects the input of the second filter unit, the input of second filter unit connects the input of the 3rd filter unit, the output end of 3rd filter unit connects the input of the 4th filter unit, the output end connection output port of 4th filter unit, output port output radio frequency output signal；Exponent number, insertion loss that the present invention in the case where ensureing ultra wideband frequency, can reduce wave filter are low, passband fluctuation, increase that the return loss of wave filter is big, improve the Out-of-band rejection of wave filter.
Description
Technical Field
The invention relates to the field of filters, in particular to an ultra-wideband band-pass filter.
Background
In recent years, with the rapid development of wireless communication technology and various communication systems, the wireless spectrum resources are becoming more and more scarce, and it is desired to develop a new and wider frequency band while improving the utilization rate of the existing spectrum. To address this bottleneck problem, the federal communications commission (FFC) in 2002 passed the commercial license (3.1GHz-10.6GHz) for Ultra-wideband (UWB) technology, which began to receive extensive attention and intensive research. In order to adapt to the development of ultra-wideband technology, the research of ultra-wideband band-pass filters, which is one of the core devices of the radio frequency front end, has become a focus and focus of attention of countless learners.
The ultra-wideband characteristic of the filter is realized by using a traditional filter structure, the filter is easy to realize, but the out-of-band rejection capability of the filter is poor, and the order of the filter must be increased to improve the selectivity of the filter, which is not beneficial to the miniaturization of the filter. Therefore, it is a challenge to improve the selectivity of the ultra-wideband filter and reduce the order of the filter.
As shown in fig. 1, when the chebyshev-type filter is applied to the design of the ultra-wideband band-pass filter, at least 6 th order chebyshev-type filter can achieve the performance of the ultra-wideband band-pass filter, but its out-of-band rejection is not good. With the development of rf integrated circuits, it is difficult to integrate the conventional chebyshev filter into the rf chip, because the passive inductor required by the 6 th-order chebyshev filter occupies a large area of the chip, which greatly increases the cost of the chip, and although the size of the product is reduced compared to the off-chip filter, the performance is not greatly improved. Therefore, the ultra-wideband band-pass filter with the traditional structure has poor performance and high cost, and is not suitable for being integrated in a radio frequency front-end chip.
Disclosure of Invention
The ultra-wideband band-pass filter can solve the technical problems of over-high order and poor selectivity of the traditional ultra-wideband filter.
In order to achieve the purpose, the invention adopts the following technical scheme:
an ultra-wideband band-pass filter comprises an input port, a first filtering unit, a second filtering unit, a third filtering unit, a fourth filtering unit and an output port, wherein a radio-frequency input signal is introduced from the input port, the input port is connected with the input end of the first filtering unit, the output end of the first filtering unit is connected with the input end of the second filtering unit, the input end of the second filtering unit is connected with the input end of the third filtering unit, the output end of the third filtering unit is connected with the input end of the fourth filtering unit, the output end of the fourth filtering unit is connected with the output port, and the output port outputs a radio-frequency output signal;
wherein,
the first filtering unit comprises an inductor L1 and a capacitor C1, and one end of the inductor L1, which is connected with the capacitor C1 in parallel, is grounded;
the second filtering unit comprises an inductor L2 and a capacitor C2, one end of the capacitor C2 is connected with one end of the inductor L2, and the other end of the capacitor C2 is connected with the other end of the inductor L1 which is connected with the capacitor C2 in parallel;
the third filtering unit comprises an inductor L4, a capacitor C3 and a capacitor C4, one end of the inductor L4 connected with the capacitor C4 in parallel is grounded, and the other end of the inductor L4 connected with the capacitor C4 in parallel is connected with the capacitor C3.
Furthermore, the fourth filtering unit includes an inductor L5, a capacitor C5, and a capacitor C6, one end of the inductor L5 connected in parallel with the capacitor C5 is connected to the capacitor C6, and the other end of the inductor L5 connected in parallel with the capacitor C5 is connected to one end of the capacitor C3.
According to the technical scheme, the invention provides the ultra-wideband band-pass filter which can ensure that under the condition of ensuring the ultra-wideband frequency band,
the order of the filter is reduced, the insertion loss is low, the in-band fluctuation is low, the return loss of the filter is increased, and the out-of-band rejection of the filter is improved.
The invention has the following beneficial effects:
(1) the order is low. The invention is a 4-order filter, has a smaller order than the ultra-wideband band-pass filter with the traditional structure, and is more suitable for the integration of a radio frequency front-end chip.
(2) The out-of-band rejection is good. Compared with the traditional filter, the filter has low order, but the third filtering unit and the fourth filtering unit both adopt secondary resonance so as to improve the out-of-band rejection degree of the filter.
(3) The insertion loss is small. The invention is a 4-order filter, the order of the filter is much smaller than that of an ultra-wideband band-pass filter with a traditional structure, the number of elements of the filter is less than that of the ultra-wideband band-pass filter with the traditional structure, and the loss in the signal transmission process is necessarily small.
(4) The fluctuation in the band is small. The invention has small fluctuation in the band and meets the requirement of the ultra-wideband band-pass filter.
(5) The return loss is large. The return loss of the invention in the band can reach-10 dB.
Drawings
FIG. 1 is a schematic circuit diagram of a Chebyshev-type ultra-wideband bandpass filter;
FIG. 2 is a circuit schematic of the ultra-wideband bandpass filter of the present invention;
fig. 3 is a graph of simulated insertion loss and return loss of the ultra-wideband bandpass filter of the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
as shown in fig. 2, the ultra-wideband band-pass filter according to the first embodiment of the present invention includes an input port P1, a first filtering unit 1, a second filtering unit 2, a third filtering unit 3, a fourth filtering unit 4, and an output port P2. The radio frequency input signal is introduced by an input port P1, the input port P1 is connected with the input end of a first filter unit 1, the output end of the first filter unit 1 is connected with the input end 2 of a second filter unit, the input end of the second filter unit 2 is connected with the input end 3 of a third filter unit, the output end of the third filter unit 3 is connected with the input end of a fourth filter unit 4, the output end of the fourth filter unit 4 is connected with an output port P2, and the output port P2 outputs a radio frequency output signal.
The first filter unit 1 adopts a parallel grounding structure.
The second filtering unit 2 adopts a series transmission structure.
The third filtering unit 3 adopts a secondary resonance structure to enhance the selectivity of high-frequency signals.
The fourth filtering unit 4 filters the signal again by using the secondary resonance, and finally outputs the radio frequency signal.
Wherein: the first filtering unit 1 is provided with a capacitor C1 and an inductor L1; the second filtering unit 2 is provided with a capacitor C2 and an inductor L2; the third filter unit 3 is provided with capacitors C3, C4 and an inductor L4; the fourth filtering unit is provided with capacitors C5 and C6 and an inductor L5; the connection relationship of the circuit is as follows:
one end of the inductor L1 of the first filtering unit connected in parallel with the capacitor C1 is grounded, one end of the capacitor C2 of the second filtering unit is connected with one end of the inductor L2, and the other end of the capacitor C2 is connected with the other end of the inductor L1 connected in parallel with the capacitor C2. One end of the third filter unit inductor L4 connected in parallel with the capacitor C4 is grounded, and the other end of the inductor L4 connected in parallel with the capacitor C4 is connected with the capacitor C3. The fourth filtering unit comprises a capacitor C6 connected with one end of an inductor L5 connected with the capacitor C5 in parallel, and a capacitor C3 connected with the other end of the inductor L5 connected with the capacitor C5 in parallel.
The third filtering unit and the fourth filtering unit are designed on the basis of the LC filter, the order of the filter is reduced by using the secondary resonance of the LC network, the order of the filter is at least two orders smaller than that of the traditional filter by adopting the mode, the selectivity of the filter is improved by using the secondary resonance, and the out-of-band rejection of the filter is good.
As shown in FIG. 3, the 3dB bandwidth of the UWB band-pass filter designed by the embodiment is 3.1GHz-10.6 GHz. The insertion loss of the ultra-wideband band-pass filter is 1.2dB, the out-of-band rejection at 2GHz is-30 dB, and the out-of-band rejection at 12GHz is less than-15 dB. By contrast, the performance of the ultra-wideband band-pass filter is far superior to that of the traditional ultra-wideband band-pass filter.
The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention by those skilled in the art should fall within the protection scope of the present invention without departing from the design spirit of the present invention.
Claims (2)
1. An ultra-wideband bandpass filter, characterized in that: the radio frequency filter comprises an input port (P1), a first filter unit (1), a second filter unit (2), a third filter unit (3), a fourth filter unit (4) and an output port (P2), a radio frequency input signal is introduced through the input port (P1), the input port (P1) is connected with the input end of the first filter unit (1), the output end of the first filter unit (1) is connected with the input end of the second filter unit (2), the input end of the second filter unit (2) is connected with the input end of the third filter unit (3), the output end of the third filter unit (3) is connected with the input end of the fourth filter unit (4), the output end of the fourth filter unit (4) is connected with the output port (P2), and the output port (P2) outputs a radio frequency output signal;
wherein,
the first filtering unit (1) comprises an inductor L1 and a capacitor C1, and one end of the inductor L1, which is connected with the capacitor C1 in parallel, is grounded;
the second filtering unit (2) comprises an inductor L2 and a capacitor C2, one end of the capacitor C2 is connected with one end of the inductor L2, and the other end of the capacitor C2 is connected with the other end of the inductor L1 which is connected with the capacitor C2 in parallel;
the third filtering unit (3) comprises an inductor L4, a capacitor C3 and a capacitor C4, one end of the inductor L4 connected with the capacitor C4 in parallel is grounded, and the other end of the inductor L4 connected with the capacitor C4 in parallel is connected with the capacitor C3.
2. The ultra-wideband bandpass filter of claim 1, wherein: the fourth filtering unit (4) comprises an inductor L5, a capacitor C5 and a capacitor C6, one end of the inductor L5, which is connected in parallel with the capacitor C5, is connected with the capacitor C6, and the other end of the inductor L5, which is connected in parallel with the capacitor C5, is connected with one end of the capacitor C3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710594335.4A CN107425823A (en) | 2017-07-20 | 2017-07-20 | A kind of ultra wide band bandpass filter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710594335.4A CN107425823A (en) | 2017-07-20 | 2017-07-20 | A kind of ultra wide band bandpass filter |
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| CN107425823A true CN107425823A (en) | 2017-12-01 |
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| CN201710594335.4A Pending CN107425823A (en) | 2017-07-20 | 2017-07-20 | A kind of ultra wide band bandpass filter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112002970A (en) * | 2020-07-23 | 2020-11-27 | 南京邮电大学 | Miniaturized millimeter wave on-chip band-pass filter |
| CN113193850A (en) * | 2021-04-01 | 2021-07-30 | 北京全路通信信号研究设计院集团有限公司 | Low-power filter |
| CN113193850B (en) * | 2021-04-01 | 2024-10-22 | 北京全路通信信号研究设计院集团有限公司 | Low-power filter |
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| US20080136560A1 (en) * | 2006-12-12 | 2008-06-12 | Amit Bavisi | Multi bandpass single-input single-output radio frequency filters |
| US20140091881A1 (en) * | 2012-09-28 | 2014-04-03 | Stmicroelectronics Sa | Passive filter |
| CN204697023U (en) * | 2015-07-16 | 2015-10-07 | 佛山市禅信通科技有限公司 | A kind of LC if bandpas filter |
| CN105490657A (en) * | 2015-11-24 | 2016-04-13 | 浙江嘉科电子有限公司 | A high-power band-pass filter |
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2017
- 2017-07-20 CN CN201710594335.4A patent/CN107425823A/en active Pending
Patent Citations (4)
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| US20080136560A1 (en) * | 2006-12-12 | 2008-06-12 | Amit Bavisi | Multi bandpass single-input single-output radio frequency filters |
| US20140091881A1 (en) * | 2012-09-28 | 2014-04-03 | Stmicroelectronics Sa | Passive filter |
| CN204697023U (en) * | 2015-07-16 | 2015-10-07 | 佛山市禅信通科技有限公司 | A kind of LC if bandpas filter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112002970A (en) * | 2020-07-23 | 2020-11-27 | 南京邮电大学 | Miniaturized millimeter wave on-chip band-pass filter |
| CN113193850A (en) * | 2021-04-01 | 2021-07-30 | 北京全路通信信号研究设计院集团有限公司 | Low-power filter |
| CN113193850B (en) * | 2021-04-01 | 2024-10-22 | 北京全路通信信号研究设计院集团有限公司 | Low-power filter |
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Application publication date: 20171201 |