CN203826525U - Low pass filter - Google Patents
Low pass filter Download PDFInfo
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- CN203826525U CN203826525U CN201420238560.6U CN201420238560U CN203826525U CN 203826525 U CN203826525 U CN 203826525U CN 201420238560 U CN201420238560 U CN 201420238560U CN 203826525 U CN203826525 U CN 203826525U
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- 238000005452 bending Methods 0.000 claims abstract description 24
- 230000008878 coupling Effects 0.000 claims abstract description 15
- 238000010168 coupling process Methods 0.000 claims abstract description 15
- 238000005859 coupling reaction Methods 0.000 claims abstract description 15
- 230000005540 biological transmission Effects 0.000 claims abstract description 10
- 230000005764 inhibitory process Effects 0.000 abstract 1
- 238000012423 maintenance Methods 0.000 abstract 1
- 238000013461 design Methods 0.000 description 6
- 238000003780 insertion Methods 0.000 description 5
- 230000037431 insertion Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
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Abstract
The utility model provides a low pass filter which adopts a stepped impedance hair pin structure. The low pass filter comprises coupling microstrip lines, a high impedance line, ends of the microstrip line and open circuit branches. The two ends of the high impedance line are connected to the coupling microstrip lines and at least two bending parts positioned between the two ends; the ends of the microstrip line are formed on the end surface where the high impedance line is connected to the coupling microstrip line; and the transmission zero points of the two open circuit branches are different and the open circuit branches are formed on the end surface where the high impedance line is connected to the coupling microstrip line. The low pass filter improves the level of the miniaturization and the compactness, the two open circuit branches widens the width of the stopband inhibition and provides convenience to integrating with other microwave circuits, and the structure is easy and the maintenance is easy.
Description
Technical field
The utility model relates to semiconductor device and filter field, relates in particular to a kind of low pass filter.
Background technology
At wireless communication field, filter is a kind of passive device of key, along with the development of wireless technology, filtering device is all had higher requirement in performance and size.
Stepped impedance hair clip type low pass filter is that first the people such as Dong Hwan Lee proposed in 1999, as shown in Figure 1, high impedance line 106 by coupled microstrip line 102 and butt coupling microstrip line forms, coupled microstrip line has microstrip line end 104, for input and output signal, feature simple in structure, that size is little and insertion loss is low that this low pass filter has, but but there is the narrow problem of resistance band.Then, proposed open circuit detail to be applied to the structure on hair clip type filter, to play the effect of bandwidth of rejection of broadening hair clip type low pass filter, but the area that this but can increase filter, has increased the size of device.For this reason, be necessary to propose the design of the high-performance low pass filter that a kind of size is little and stopband is wide.
Utility model content
The utility model is intended to one of address the above problem, and a kind of low pass filter is provided, and realizes the high performance low pass filter design that size is little and stopband is wide.
For achieving the above object, the utility model embodiment provides following technical scheme:
A kind of low pass filter, comprising:
Adopt stepped impedance hair clip type structure, comprise coupled microstrip line, high impedance line, microstrip line end and open circuit detail; Wherein,
High impedance line, its two ends butt coupling microstrip line, and between two-end-point, at least there are two bendings;
Microstrip line end, is formed on the end face of high impedance line butt coupling microstrip line;
Open circuit detail, two open circuit details that transmission zero is different, are formed on the end face of high impedance line butt coupling microstrip line.
Preferably, described bending is right angle bending.
Preferably, there are two open circuit details, and the characteristic impedance of two open circuit details is identical.
Preferably, the transmission zero difference of two open circuit details.
Preferably, the length of open circuit detail is 1/4th of its transmission zero corresponding wavelength.
Preferably, open circuit detail lays respectively between microstrip line end and high impedance line.
Preferably, at least one open circuit detail is bending structure.
Preferably, the bending of open circuit detail is right angle bending.
The low pass filter that the utility model embodiment provides, adopt the high impedance line of multiple bendings, and open circuit detail is formed on the end face of high impedance line butt coupling microstrip line, miniaturization, compactness have had further raising, and two open circuit details have increased the width that stopband suppresses, and passband insertion loss is little, single-sided structure, be easy to other microwave circuits integrated, simple in structure, be easy to processing.
Brief description of the drawings
Fig. 1 is the structural representation of traditional stepped impedance hair clip type low pass filter;
Fig. 2 is according to the structural representation of the low pass filter of the utility model embodiment;
Fig. 3 is the curve synoptic diagram of the frequency-echo/insertion loss of the low pass filter of the utility model embodiment.
Embodiment
For above-mentioned purpose of the present utility model, feature and advantage can be become apparent more, below in conjunction with accompanying drawing, embodiment of the present utility model is described in detail.
A lot of details are set forth in the following description so that fully understand the utility model; but the utility model can also adopt other to be different from alternate manner described here and implement; every content that does not depart from technical solutions of the utility model; any simple modification, equivalent variations and the modification following examples done according to technical spirit of the present utility model; all still belong in the scope of technical solutions of the utility model protection, therefore the utility model is not subject to the restriction of following public specific embodiment.
As shown in Figure 2, in the present embodiment, this low pass filter adopts stepped impedance hair clip type structure, comprise coupled microstrip line 5, high impedance line 6, microstrip line end 4 and open circuit detail 7, wherein, high impedance line 6, its two ends butt coupling microstrip line 5, and between two connection end points, at least there are two bendings; Microstrip line end 4, is formed on the end face of high impedance line butt coupling microstrip line; The different open circuit detail of open circuit 7, two transmission zeros of detail, is formed on the end face of high impedance line butt coupling microstrip line.
In the present embodiment, this low pass filter can be formed on medium substrate, as shown in Figure 2, on the upper surface of medium substrate 1, be formed with etched circuit layer 3, this etched circuit layer has formed coupled microstrip line 5, high impedance line 6, microstrip line end 4 and open circuit detail 7, is formed with ground metal layer 2 at the lower surface of medium substrate 1.
In the present embodiment, high impedance line 6 has two bendings between two connection end points, and each bending is the right angle bending of similar hump shape, connection end point be positioned at coupled microstrip line 5 directly over end face 5-1 on.Be understandable that, in other embodiments, the quantity of bending is only example herein, can select according to concrete design requirement quantity and the shape of bending.Right angle bending in this embodiment is more easily connected up and realizes.High impedance line is the circuit line that can be equivalent to inductance.
Open circuit detail is positioned on the end face 5-1 of coupled microstrip line 5 at high impedance line 6 connection end point places, in the present embodiment, adopt two open circuit details, lay respectively between microstrip line end 4 and high impedance line 6, each open circuit detail can have identical characteristic impedance but have different length, and the two has different transmission zeros like this, to suppress the high-frequency harmonic of different frequency, the length of open circuit detail can be 1/4th of its transmission zero corresponding wavelength, to obtain better High frequency filter performance.In the time that the length of open circuit detail exceedes the height of the high impedance line after bending, open circuit detail can be bent, for example carry out the bending at right angle, to reduce the size of overall filter.
Same, microstrip line end 4 is also positioned on the end face 5-1 of coupled microstrip line 5 at high impedance line 6 connection end point places, and microstrip line end 4 can be the matched line of 50 ohm, for the input and output port of signal.The miniaturization of this device, compactness have had further raising, and two open circuit details have increased the width that stopband suppresses, and are easy to other microwave circuits integratedly, simple in structure, are easy to processing.
In the time of design low pass filter of the present utility model, first determine the cut-off frequency f of low pass filter
c, select pcb board material, specify relative dielectric constant and the thickness of sheet material.According to stepped impedance hair clip type low pass filter design theory, choose width W 1, the total length L of width W 1, spacing g, length L 2 and the high impedance line of coupled microstrip line, making filter cutoff frequency is f
c.High impedance line is bent, and its total length is still L.Then between high impedance line and matched line, increase by two details, adjust its length, make it the transmission zero of introducing at the high-frequency harmonic place of filter.If detail length is greater than the high impedance line after bending, detail can be bent.The filter of design can pass through to regulate the width W 3 of detail, and the overall performance of Optimal Filter is carried out in position.
The filter that the utility model provides can directly be printed on frequency PCB plate.The live width of practical filter, line length be difference with the difference of cut-off frequency and pcb board material.
The low pass filter that the embodiment of the present invention provides has good filtering performance, as shown in Figure 3, is the curve synoptic diagram of the frequency-echo/insertion loss of a specific embodiment, wherein S
21for insertion loss parameter, S
11for return wave loss parameter, in this embodiment ,-3dB cut-off frequency is 1.2GHz, and-15dB stopband suppresses from 1.9GHz to 10.3GHz.
The utility model discloses as above with preferred embodiment, but not in order to limit the utility model.Any those of ordinary skill in the art, do not departing from technical solutions of the utility model scope situation, all can utilize method and the technology contents of above-mentioned announcement to make many possible variations and modification to technical solutions of the utility model, or be revised as the equivalent embodiment of equivalent variations.Therefore, every content that does not depart from technical solutions of the utility model,, all still belongs in the scope of technical solutions of the utility model protection any simple modification made for any of the above embodiments, equivalent variations and modification according to technical spirit of the present utility model.
Claims (8)
1. a low pass filter, is characterized in that, adopts stepped impedance hair clip type structure, comprises coupled microstrip line, high impedance line, microstrip line end and open circuit detail; Wherein,
High impedance line, its two ends butt coupling microstrip line, and between two-end-point, at least there are two bendings;
Microstrip line end, is formed on the end face of high impedance line butt coupling microstrip line;
Open circuit detail, is formed on the end face of high impedance line butt coupling microstrip line.
2. low pass filter according to claim 1, is characterized in that, described bending is right angle bending.
3. low pass filter according to claim 1, is characterized in that, have two open circuit details, and the characteristic impedance of two open circuit details is identical.
4. low pass filter according to claim 3, is characterized in that, the transmission zero difference of two open circuit details.
5. low pass filter according to claim 4, is characterized in that, the length of open circuit detail is 1/4th of its transmission zero corresponding wavelength.
6. low pass filter according to claim 3, is characterized in that, open circuit detail lays respectively between microstrip line end and high impedance line.
7. low pass filter according to claim 1, is characterized in that, at least one open circuit detail is bending structure.
8. low pass filter according to claim 7, is characterized in that, the bending of open circuit detail is right angle bending.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420238560.6U CN203826525U (en) | 2014-05-09 | 2014-05-09 | Low pass filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420238560.6U CN203826525U (en) | 2014-05-09 | 2014-05-09 | Low pass filter |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106067580A (en) * | 2016-08-03 | 2016-11-02 | 华南理工大学 | Ultra-wide stop-band low-pass filter based on step impedance resonator |
| CN115513619A (en) * | 2022-09-23 | 2022-12-23 | 中国科学院物理研究所 | Microstrip pattern layer, preparation method thereof and extremely wide stopband low-pass filter |
-
2014
- 2014-05-09 CN CN201420238560.6U patent/CN203826525U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106067580A (en) * | 2016-08-03 | 2016-11-02 | 华南理工大学 | Ultra-wide stop-band low-pass filter based on step impedance resonator |
| CN115513619A (en) * | 2022-09-23 | 2022-12-23 | 中国科学院物理研究所 | Microstrip pattern layer, preparation method thereof and extremely wide stopband low-pass filter |
| CN115513619B (en) * | 2022-09-23 | 2023-10-03 | 中国科学院物理研究所 | Microstrip pattern layer, preparation method thereof and ultra-wide stop band low-pass filter |
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Effective date of registration: 20240401 Address after: 100010 No. 2 Hutong, Da take lantern, Beijing, Dongcheng District Patentee after: Beijing Zhongke micro Investment Management Co.,Ltd. Country or region after: China Address before: 100029 Beijing city Chaoyang District Beitucheng West Road No. 3 Patentee before: Institute of Microelectronics, Chinese Academy of Sciences Country or region before: China |