CN202205871U - Low-pass micro-strip filter - Google Patents
Low-pass micro-strip filter Download PDFInfo
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- CN202205871U CN202205871U CN2011203264431U CN201120326443U CN202205871U CN 202205871 U CN202205871 U CN 202205871U CN 2011203264431 U CN2011203264431 U CN 2011203264431U CN 201120326443 U CN201120326443 U CN 201120326443U CN 202205871 U CN202205871 U CN 202205871U
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- little band
- band section
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Abstract
A low-pass micro-strip filter is made on a PCB, and comprises a first micro-strip, a second micro-strip, a third micro-strip and an m-shaped micro-strip group, wherein the micro-strip group comprises a first micro-strip section, a second micro-strip section and a third micro-strip section which are respectively connected with the first micro-strip, the second micro-strip and the third micro-strip, as well as a fourth micro-strip section connected with the three micro-strip sections; the first micro-strip section, the second micro-strip section and the third micro-strip section are the vertical lines of the m shape from the left to the right in sequence, and the fourth micro-strip section is the horizontal line of the m shape; two bent parts are formed in the middles of the first micro-strip section, the second micro-strip section and the third micro-strip section; the first micro-strip is provided with an input end; and the third micro-strip section is provided with an output end. Therefore, the lower-pass micro strip filter has a simple structure.
Description
[technical field]
The utility model relates to wireless communication field, particularly relates to a kind of low pass microstrip filter.
[background technology]
Along with modern microwave communication, the especially fast development of mobile communication, wireless communication technology, system is increasingly high to the selectivity of communication.Filter is a kind of device that is used for separating the different frequency microwave signal.Its main effect is to suppress unwanted signal, and it can not be passed through, and the signal that only letting needs passes through.Microstrip filter is widely used in military project group circle and single chip microwave integrated circuit.In the microwave circuit system, the performance of filter has very big influence to the performance index of circuit, we can say the quality of the good and bad directly decision product of filter.Therefore how designing one has high performance filter, and system has very important meaning to the design microwave circuit.The rapid growth of radio communication and other removable Receiver And Transmitter application makes that the microwave circuit system applies is extensive in recent years, and wherein making filter with little band is that it mainly one of is used, and has particularly obtained especially using widely in field of wireless communication.
In the wireless communication technology fast development, increasingly high requirement has been proposed for the electric property of filter.For satisfying the demand of radio communication service, China has stipulated the technical parameter of 2.4GHz frequency range wireless transmitting device according to the situation of frequency partition regulation and frequency spectrum use.Wherein require scattering transmission power less than-30 decibels above milliwatts/megahertz (dBm/1MHz).And according to the characteristic of the PA that uses on WLAN (Wireless Local Area Network, the WLAN) scheme (Power Amplifier, power amplifier) and see the harmonic wave rich.Can find out that from the spuious resolution chart of the traditional wlan product prevention at radio-frequency port of Fig. 1 second harmonic and four-time harmonic interference signal still are more intense, very approaching-30dBm/1MHz, do not have surplus basically.This just needs filter little except the band internal loss, and the outer rejection ratio of band wants high.Particularly the inhibition ability at the frequency multiplication place of working frequency points has high request, otherwise may interfere with the operation of other equipment.
Wlan product is universal in recent years, and not only the performance to filter has proposed high request, and also the miniaturization to filter has also proposed very high requirement.Just because of the miniaturization requirement of equipment much designs producer and adopts integrated filter.But integrated filter construction is complicated, cost is high and the interior Insertion Loss of band is big, and on the harmonic wave of 2.4G, does not have good behaviour.
[utility model content]
Based on this, be necessary to provide a kind of low pass microstrip filter simple in structure.
A kind of low pass microstrip filter; On printed circuit board (PCB), process; It is characterized in that, comprise that first little band, second little band, the 3rd little band reach little band group of " mountain " font, wherein; Said little band group comprises first little band section, second little band section and the 3rd little band section that is connected with said first little band, second little band and the 3rd little band respectively, also comprises the 4th little band section that is connected with three little band sections; Said first little band section, second little band section and the 3rd little band section are followed successively by down the vertical line of " mountain " font number from a left side, and the 4th little band section is the horizontal line of " mountain " font; Said first little band section, second little band section and the 3rd little band Duan Jun are provided with two bends at the middle part; Said first little band section is provided with input, and the said the 3rd little band section is provided with output.
Preferably, the in the opposite direction and end of two said bend interior angles of same little band section links to each other, and two ends extend to form two straightways that are parallel to each other respectively round about in addition.
Preferably, the said straightway on said first little band section, second little band section and the 3rd little band section is parallel to each other and perpendicular to the said the 4th little band section.
Preferably, two said bends of said first little band section comprise first bend, second bend, and wherein said first bend is located at down " mountain " font left with respect to said second bend; Two said bends of said second little band section comprise the 3rd bend, the 4th bend, and it is right-hand that wherein said the 3rd bend is located at down " mountain " font with respect to said the 4th bend; Two said bends that reach the said the 3rd little band section comprise the 5th bend, the 6th bend, and it is right-hand that wherein said the 5th bend is located at down " mountain " font with respect to said the 6th bend.
Preferably, the bent angle of said bend is a fillet, and the angle of the extended line at said fillet two ends is 90 degree.
Preferably, said first little band section, the 3rd little band section are fillet with the angle of the said the 4th little band section junction, two ends; Said second little band section is the right angle with the angle of cut of the said the 4th little band section junction.
Preferably, said first little band, second little band and the 3rd little band are length 93 mils, the rectangle of width 63 mils.
Preferably, said first little band section, second little band section, the 3rd little band section and the 4th little band section printing width on said printed circuit board are 8 mils.
Preferably, said low pass microstrip filter is operated in 2.4GHz～2.484GHz band limits.
Preferably, the length of side of said low pass microstrip filter is 5.3 millimeters, and width is 5.1 millimeters.
Technique scheme is through processing the low pass microstrip filter by three little bands and little band group on printed circuit board (PCB); Little band group comprises three little band sections and three the 4th little band sections that little band section connects that are connected with three little bands; See that thus this low pass microstrip filter is simple in structure.
[description of drawings]
Fig. 1 is the spuious resolution chart of certain traditional wlan product prevention at radio-frequency port;
Fig. 2 is the PCB domain of low pass microstrip filter among the embodiment;
Fig. 3 is the theory diagram of low pass microstrip filter shown in Figure 2;
Fig. 4 is the return loss simulation result figure of low pass microstrip filter shown in Figure 2;
Fig. 5 is the transmission characteristic simulation result figure of low pass microstrip filter shown in Figure 2;
Fig. 6 is certain traditional lamination paster band pass filter electrical characteristic table.
[embodiment]
For the purpose, technical scheme and the advantage that make the utility model is clearer, below in conjunction with accompanying drawing and embodiment, to the utility model further explain.Should be appreciated that specific embodiment described herein only in order to explanation the utility model, and be not used in qualification the utility model.
Can find out that from the spuious resolution chart of the traditional wlan product prevention at radio-frequency port of Fig. 1 second harmonic and four-time harmonic interference signal still are more intense, very approaching-30dBm/1MHz, do not have surplus basically.This just needs filter little except the band internal loss, and the outer rejection ratio of band wants height, particularly at the inhibition Capability Requirement at the frequency multiplication place of working frequency points, otherwise may interfere with the operation of other equipment.
The present technique scheme is through understanding the characteristics of 2.4GHz frequency range wireless transmitting device system; With the maximally-flat low pass filter is prototype; And microstrip filter is optimized processing, require little, the principle of apply in a flexible way hair clip filter and open stub to Insertion Loss on the 2.4GHz frequency range as far as possible; And the mode of combination electromagnetism hybrid coupled, make it on harmonic wave suppresses, obtain good effect.
Like Fig. 2, shown in 3, a kind of low pass microstrip filter comprises that first is little little little with 130 and fall little band group of " mountain " font with the 120, the 3rd with 110, second.The printing length of side of low pass microstrip filter is 5.3 millimeters, and width is 5.1 millimeters, and other microstrip filter volumes are few relatively for this size, thereby it is few to take the pcb board space, and production cost is extremely low.In the present embodiment, copper becomes the low pass microstrip filter on FR4 material printed circuit board upper berth, in other embodiments, can realize that the material of said function is paved with other and process.
In this enforcement, first littlely is with 110, second littlely to be with the 120 and the 3rd littlely to be with 130 for rectangle, and its length of side is preferably 93 mils, wide 63 mils that are preferably.In other embodiments, can be the fillet of other sizes, the shape that can realize said function such as trapezoidal.Little band group comprises first little band section 210, second little band section the 220, the 3rd little band section the 230 and the 4th little band section 240.First little band section 210 littlely is with 110 to be connected with first, and second little band section 220 connects with second littlely is with 120 to be connected, and the 3rd little band sections 230 littlely is with 130 to be connected with the 3rd, and the 4th little band sections 240 and aforementioned three little bands section are connected.First little band section 210, second little band section the 220 and the 3rd little band section 240 is followed successively by down the vertical line (being the vertical line of " mountain " font number from the right side) of " mountain " font number from a left side, and the 4th little band section 240 is the horizontal line of " mountain " font.
First little band section 210, second little band section the 220, the 3rd little band section the 230 and the 4th little band section 240 is printed width on said printed circuit board be 8 mils.In other embodiments, cooperate miscellaneous part to make distortion, can keep under the constant situation of performance of filter, can in 6 mil to 10 mil scopes, suitably adjust printing width.
First little band section the 210, the 3rd little band section 230 is connected with the 4th little band section 240 two ends, and the angle of junction is a fillet, and the angle of the extended line at fillet two ends is 90 degree.In other embodiments, cooperate miscellaneous part to make distortion, can keep under the constant situation of performance of filter, first little band section the 210, the 3rd little band section the 230 and the 4th little band section junction, 240 two ends can be corner cut, also can be the right angle.
It is tie point with the 4th cross shaped microstrip 246 that the 4th little band section 240 is provided with the 4th cross shaped microstrip 246, the second little bands section the 220 and the 4th little bands sections 240, and the angle of junction is the right angle.In other embodiments, cooperate miscellaneous part to make distortion, can keep under the constant situation of performance of filter, second little band section the 220 and the 4th little band section, 240 junctions can be fillet.
First little band section 210, second little band section the 220 and the 3rd little band section 230 all is provided with two bends at the middle part; First little band section 210 is provided with input, and the 3rd little band section 230 is provided with output.
In the present embodiment, the bent angle of bend is a fillet, and the angle of the extended line at its two ends is 90 degree (being that angle A is 90 degree).In other are implemented, cooperate miscellaneous part to make distortion, can keep under the constant situation of performance of filter, the bent angle of bend can be corner cut, also can be the right angle.
Two bends on first little band section 210 comprise first bend 212 and second bend 214; First bend 212 an and end in the opposite direction with second bend, 214 interior angles links to each other; Wherein first bend 212 is located at down " mountain " font left with respect to second bend 214.
First bend 212 and second bend, 214 disjunct two ends extend to form two straightways that are parallel to each other respectively round about, and first bend 212 extends to form first straightway, 213, the second bends and extends to form second straightway 215.First straightway 213 is parallel with second straightway 215.On second straightway 215, being provided with the first cross shaped microstrip, 216, the first cross shaped microstrips 216, to fall the left end of the little band section of " mountain " font relatively be input.
Two bends on second little band section 220 comprise the 3rd bend 222 and the 4th bend 224; The 3rd bend 222 an and end in the opposite direction with the 4th bend 224 interior angles links to each other, and wherein to be located at down " mountain " font with respect to the 4th bend 224 right-hand for the 3rd bend 222.
The 3rd bend 222 and the 4th bend 224 disjunct two ends extend to form two straightways that are parallel to each other respectively round about, and the 3rd bend 222 extends to form the 3rd straightway 223, the four bends 224 and extends to form the 4th straightway 225.The 3rd straightway 223 is parallel with the 4th straightway 225.On the 4th straightway 225, be provided with the second cross shaped microstrip 226 that is used to connect microstrip line.
Two bends on the 3rd little band section 230 comprise the 5th bend 232 and the 6th bend 234; The 5th bend 232 an and end in the opposite direction with the 6th bend 234 interior angles links to each other, and wherein to be located at down " mountain " font with respect to the 6th bend 234 right-hand for the 5th bend 232.
The 5th bend 232 and the 6th bend 234 disjunct two ends extend to form two straightways that are parallel to each other respectively round about, and the 5th bend 232 extends to form the 5th straightway 233, the six bends 234 and extends to form the 6th straightway 235.The 5th straightway 233 is parallel with the 6th straightway 235.On the 6th straightway 235, being provided with cross shaped microstrip 236, the three cross shaped microstrips 236, to fall the right-hand member of the little band section of " mountain " font relatively be output.
Straightway on first little band section 210, second little band section the 220 and the 3rd little band section 220, i.e. first straightway 213, second straightway 215, the 3rd straightway 223, the 4th straightway 225, the 5th straightway 233 and the 6th straightway 235 is parallel to each other and perpendicular to the 4th little band sections 240.Be appreciated that; Straightway is parallel to each other and straightway is the special case in numerous embodiment perpendicular to the 4th little band section 240; Cooperate miscellaneous part to make distortion; Can keep can forming angle between the straightway under the constant situation of performance of filter, straightway also can be not orthogonal to the 4th little band section 240 simultaneously.
In the present embodiment; The interior angle of first bend 212, the 4th bend 224 and the 6th bend 234 falls " mountain " font all to the right relatively, and the interior angle of second bend 214, the 3rd bend 222 and the 5th bend 234 falls " mountain " font all left relatively, is appreciated that; In other embodiments; Cooperate miscellaneous part to make distortion, can keep under the constant situation of performance of filter, the bend direction on each little band section can be made any distortion; For example first bend 212, the 3rd bend 222 and the 5th bend 232 can be in the same way, and second bend 212, the 4th bend 224 and the 6th bend 234 can be in the same way; First bend 212 and the 3rd bend 222 are reverse with the 5th bend 232 in the same way, and second bend 212 and the 4th bend 224 are reverse with the 6th bend 234 in the same way.
In the present embodiment, low pass microstrip filter band trap wave unit, trap wave unit refer to down little band group of " mountain " font, and the low pass microstrip filter of band trap wave unit is prototype with the maximum flat filter, and combine the characteristics of hair clip filter.Like the theory diagram of the low pass microstrip filter of Fig. 3 band trap wave unit, this design is made up of 26 sections microstrip lines.The input of this low pass microstrip filter, output impedance are 50 ohm.
In the present embodiment, the Fast design method that the conventional filter design formula is combined with microstrip circuit emulation.Result with the method Design of Filter is identical basically with the result of final emulation; Utilization electromagnetism hybrid coupled mode is also passed through control coupling coefficients such as spacing, brachium; Confirm hair clip brachium, hair clip spacing, hair clip live width and tap position through traditional design method; And pass through ADS (Advanced Design System, advanced design system) emulation and optimize.
Like Fig. 4, shown in 5, the simulation result figure of low pass microstrip filter of band trap wave unit, S11 representes return loss, S21 representes the insertion loss transmitted.
Can find out from this simulation result, in free transmission range, insert loss less than 0.35dB, return loss is less than-23dB.In the 2.4GHz to 2.484GHz of WLAN 802.11b/g/n band limits.Insert loss and be merely 0.24dB to 0.32dB, compare integrated filter Insertion Loss and want much little.2.4GHz the echo Insertion Loss at frequency range place reaches-and 28dB is to-34.8dB.So this application of low pass filters is in 2.4GHz frequency range wireless transmitting device system, performance is very good.The more important thing is suppressing to have at least on second harmonic component, four-time harmonic component and the third-harmonic component-amount of suppression of 31dB, particularly on four-time harmonic, even can reach-amount of suppression of 130dB, directly attenuate unwanted signal.
The electrical characteristic table of certain traditional lamination paster band pass filter shown in Figure 6, its frequency range 2.4GHz to 2.5GHz is wideer than 2.4GHz to the 2.484GHz band limits of present technique scheme, and the stability that relatively embodies the present technique scheme is better; The insertion loss of integrated filter is that 2.5dB to 2.8dB is more much bigger than present technique scheme 0.24dB to 0.32dB; Integrated filter return loss be 10dB than present technique scheme echo Insertion Loss less than-23dB is much bigger, the filtering performance that relatively embodies the present technique scheme is better.
The above embodiment has only expressed several kinds of execution modes of the utility model, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the utility model claim.Should be pointed out that for the person of ordinary skill of the art under the prerequisite that does not break away from the utility model design, can also make some distortion and improvement, these all belong to the protection range of the utility model.Therefore, the protection range of the utility model patent should be as the criterion with accompanying claims.
Claims (10)
1. low pass microstrip filter; On printed circuit board (PCB), process; It is characterized in that, comprise that first little band, second little band, the 3rd little band reach little band group of " mountain " font, wherein; Said little band group comprises first little band section, second little band section and the 3rd little band section that is connected with said first little band, second little band and the 3rd little band respectively, also comprises the 4th little band section that is connected with three little band sections; Said first little band section, second little band section and the 3rd little band section are followed successively by down the vertical line of " mountain " font number from a left side, and the 4th little band section is the horizontal line of " mountain " font; Said first little band section, second little band section and the 3rd little band Duan Jun are provided with two bends at the middle part; Said first little band section is provided with input, and the said the 3rd little band section is provided with output.
2. low pass microstrip filter according to claim 1 is characterized in that, the in the opposite direction and end of two said bend interior angles of same little band section links to each other, and two ends extend to form two straightways that are parallel to each other respectively round about in addition.
3. low pass microstrip filter according to claim 2 is characterized in that, the said straightway on said first little band section, second little band section and the 3rd little band section is parallel to each other and perpendicular to the said the 4th little band section.
4. low pass microstrip filter according to claim 2; It is characterized in that; Two said bends of said first little band section comprise first bend, second bend, and wherein said first bend is located at down " mountain " font left with respect to said second bend;
Two said bends of said second little band section comprise the 3rd bend, the 4th bend, and it is right-hand that wherein said the 3rd bend is located at down " mountain " font with respect to said the 4th bend; And
Two said bends of the said the 3rd little band section comprise the 5th bend, the 6th bend, and it is right-hand that wherein said the 5th bend is located at down " mountain " font with respect to said the 6th bend.
5. low pass microstrip filter according to claim 1 and 2 is characterized in that, the bent angle of said bend is a fillet, and the angle of the extended line at said fillet two ends is 90 degree.
6. low pass microstrip filter according to claim 1 is characterized in that, said first little band section, the 3rd little band section are fillet with the angle of the said the 4th little band section junction, two ends; Said second little band section is the right angle with the angle of cut of the said the 4th little band section junction.
7. low pass microstrip filter according to claim 1 is characterized in that, said first little band, second little band and the 3rd little band are length 93 mils, the rectangle of width 63 mils.
8. low pass microstrip filter according to claim 4 is characterized in that, said first little band section, second little band section, the 3rd little band section and the 4th little band section are printed width on said printed circuit board be 8 mils.
9. low pass microstrip filter according to claim 1 is characterized in that, said low pass microstrip filter is operated in 2.4GHz～2.484GHz band limits.
10. low pass microstrip filter according to claim 1 is characterized in that, the length of side of said low pass microstrip filter is 5.3 millimeters, and width is 5.1 millimeters.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203264431U CN202205871U (en) | 2011-09-01 | 2011-09-01 | Low-pass micro-strip filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203264431U CN202205871U (en) | 2011-09-01 | 2011-09-01 | Low-pass micro-strip filter |
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| Publication Number | Publication Date |
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| CN202205871U true CN202205871U (en) | 2012-04-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011203264431U Expired - Lifetime CN202205871U (en) | 2011-09-01 | 2011-09-01 | Low-pass micro-strip filter |
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| CN (1) | CN202205871U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102969550A (en) * | 2011-09-01 | 2013-03-13 | 深圳市卓翼科技股份有限公司 | Low-pass microstrip filter |
-
2011
- 2011-09-01 CN CN2011203264431U patent/CN202205871U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102969550A (en) * | 2011-09-01 | 2013-03-13 | 深圳市卓翼科技股份有限公司 | Low-pass microstrip filter |
| CN102969550B (en) * | 2011-09-01 | 2015-09-30 | 深圳市卓翼科技股份有限公司 | low-pass micro-strip filter |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: TIANJIN ZHUODA TECHNOLOGY DEVELOPMENT CO., LTD. Effective date: 20130322 |
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| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20130322 Address after: 518055 Guangdong city of Shenzhen province Nanshan District Xili Hirayama Private Technology Industrial Park 5 Patentee after: Shenzhen Zowee Technology Co., Ltd. Patentee after: Zowee Tianjin Technology Co., Ltd. Address before: 518055 Guangdong city of Shenzhen province Nanshan District Xili Hirayama Private Technology Industrial Park 5 Patentee before: Shenzhen Zowee Technology Co., Ltd. |
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| CX01 | Expiry of patent term |
Granted publication date: 20120425 |
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| CX01 | Expiry of patent term |