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對(duì)于板級(jí)SMA頭連接器參數(shù)提取方法您知道多少,下文中,德索五金電子工防師將會(huì)針對(duì)“板級(jí)SMA頭連接器參數(shù)提取方法”做一些分析,希望我們的分析對(duì)于您了解sma頭連接器有一定的幫助。

一、 前言

射頻微波及高頻高速測(cè)試中,SMA 接頭扮演著相當(dāng)重要的一個(gè)角色,它連接了測(cè)量?jī)x器與待測(cè)電路,可以說(shuō)是測(cè)量?jī)x器與待測(cè)電路之間的橋梁,而在傳統(tǒng)中的一般高速電路的測(cè)量中,一般皆沒(méi)有將SMA 接頭的效應(yīng)考慮進(jìn)去,往往所測(cè)量出來(lái)的結(jié)果,并不是一個(gè)單純的電路板參數(shù),而是包含著SMA接頭效應(yīng)在里頭的電路板參數(shù),而此時(shí)將測(cè)量的電路板參數(shù)再進(jìn)行后續(xù)的各種分析時(shí),因?yàn)椴](méi)有減去SMA接頭的效應(yīng),所獲得的后續(xù)分析結(jié)果,準(zhǔn)確度將會(huì)受到影響。

二、使用HFSS提取SMA接頭參數(shù)

在本研究論文中,第一階段SMA接頭參數(shù)的提取,我們使用HFSS仿真軟件進(jìn)行,我們繪制出兩個(gè)SMA接頭對(duì)接的3D Model,對(duì)于后續(xù)的S-Parameter分析結(jié)果,影響最主要為T(mén)eflon介質(zhì)材質(zhì)的部份,因此我們?cè)谠O(shè)計(jì)SMA 3D Model時(shí),我們主要針對(duì)SMA接頭中Teflon材質(zhì)其中的Relative Permeability與Loss tangent兩者進(jìn)行調(diào)整,并且與測(cè)量的情形進(jìn)行比較找出最正確的值。

由于網(wǎng)絡(luò)分析儀測(cè)量上的限制,我們必須將兩個(gè)SMA接頭連接起來(lái)(如圖一),并且使用時(shí)域反射儀測(cè)量對(duì)接后的SMA接頭阻抗是否為50歐,之后再接上網(wǎng)絡(luò)分析儀進(jìn)行測(cè)量,測(cè)量的范圍為50MHz到10GHz,測(cè)量結(jié)果(如圖二)。

圖一、SMA 接頭對(duì)接圖

圖二、SMA接頭測(cè)量S11參數(shù)曲線圖

我們從網(wǎng)絡(luò)分析儀取得雙SMA接頭對(duì)接的S11參數(shù)之后,接下來(lái)就要開(kāi)始使用HFSS來(lái)進(jìn)行SMA接頭3D Model的制作,首先第一步就是先制作好SMA接頭的3D Model(如圖三),接著按照流程圖(如圖四)上的流程,進(jìn)行參數(shù)的提取,測(cè)量與模擬的結(jié)果,不斷的進(jìn)行兩者間的對(duì)照,假設(shè)模擬結(jié)果不符合測(cè)量的結(jié)果,即返回3D Model進(jìn)行Teflon材質(zhì)參數(shù)上的修改,最后即可得到一個(gè)正確的單一SMA接頭的3D Model。

圖三、SMA接頭3D Model繪制圖

圖四、使用HFSS提取SMA接頭參數(shù)流程圖

模擬的頻率范圍為100MHz到10GHz,而在Teflon材質(zhì)Relative Permeability參數(shù)等于3.317,Loss tangent參數(shù)等于0.0035時(shí),我們得到了與測(cè)量結(jié)果吻合的S11參數(shù)(如圖五)。

圖五、SMA接頭S11仿真曲線圖

我們使用Matlab將測(cè)量的結(jié)果與模擬的結(jié)果進(jìn)行兩者間的對(duì)照,取樣的點(diǎn)數(shù)為201點(diǎn),頻率的范圍為50MHz到10GHz。由圖六可以看到,整體的S11參數(shù)大致上與測(cè)量結(jié)果吻合,但是在頻率5GHz之后,數(shù)值部份已經(jīng)漸漸無(wú)法相當(dāng)吻合,我想這可以歸究于S11參數(shù)是反射系數(shù)的關(guān)系,而整體的S11參數(shù)是很不好測(cè)量的,因?yàn)槠鋽?shù)值都是在-30dB到-60dB之間,是相當(dāng)小的值,因此如果有不小心動(dòng)到測(cè)量的線路,或是線路有抖動(dòng)的問(wèn)題,都會(huì)造成量測(cè)結(jié)果的不準(zhǔn)確,而模擬的參數(shù)對(duì)于實(shí)際上所測(cè)量的結(jié)果,通常也都會(huì)有一定程度上的誤差,因此只能做到盡量與測(cè)量結(jié)果吻合。

圖六、模擬與測(cè)試結(jié)果對(duì)照

三、使用ADS進(jìn)行SMA Model的驗(yàn)證

在使用HFSS提取完SMA接頭3D Model的S-Parameter之后,接下來(lái)所要做的就是使用ADS (Advanced Design System )進(jìn)行SMA接頭參數(shù)的驗(yàn)證。我們可以將S-Parameter轉(zhuǎn)成矩陣的表示方法(如圖七),假設(shè)SMA接頭參數(shù)各為[A]及[C],電路板參數(shù)為[B],量測(cè)結(jié)果為[D]即可得到圖七中的式子。

圖七、電路參數(shù)矩陣示意圖

在本論文中,我們另外制作了2cm與4cm長(zhǎng)傳輸線的電路板(如圖八)進(jìn)行模擬與測(cè)量的互相驗(yàn)證,驗(yàn)證的方法為;先使用網(wǎng)絡(luò)分析儀測(cè)量實(shí)際2cm與4cm長(zhǎng)傳輸線電路板之參數(shù),接著將所測(cè)量出的結(jié)果代入ADS中,即可得到分析之結(jié)果(如圖九及圖十)。

圖八、2cm與4cm長(zhǎng)傳輸線電路板

 

圖九、2cm長(zhǎng)傳輸線電路板S參數(shù)

圖十、4cm長(zhǎng)傳輸線電路板S參數(shù)

接著再將先前由HFSS所提取出的SMA接頭參數(shù),代入ADS中,即可取得模擬的結(jié)果,我們?cè)賹⒛M的結(jié)果與量測(cè)的結(jié)果,進(jìn)行兩者間的互相驗(yàn)證(如圖十一及圖十二),從圖中我們可以發(fā)現(xiàn),兩者間的對(duì)照可以說(shuō)是非常吻合,而在2GHz的共振點(diǎn),是由電路板的共振所造成的,因此從兩者間的驗(yàn)證,我們可以得知之前從HFSS之所提取出的SMA接頭參數(shù),是正確無(wú)誤的。而在往后的高速電路測(cè)試模擬中,我們即可代入此SMA 接頭的參數(shù),將SMA接頭的效應(yīng)考慮進(jìn)去,所得到的結(jié)果將會(huì)更為正確,也將會(huì)是一個(gè)更為單純,不包括SMA效應(yīng)在里頭的電路板參數(shù)。

圖十一、2cm傳輸線模擬與測(cè)量對(duì)照?qǐng)D

圖十二、4cm模擬與測(cè)量對(duì)照?qǐng)D

四、結(jié)論

本論文成功地完成使用計(jì)算機(jī)輔助設(shè)計(jì)軟件Ansoft HFSS進(jìn)行SMA接頭的3D Model的繪制及模擬,并且在HFSS中調(diào)整SMA接頭的介質(zhì)參數(shù),而在Teflon材質(zhì)Relative Permeability參數(shù)等于3.317,Loss tangent參數(shù)等于0.0035時(shí),我們得到了與測(cè)量結(jié)果吻合的S參數(shù),并且使用ADS軟件平臺(tái),驗(yàn)證獲得2公分及4公分長(zhǎng)傳輸線具有相同模擬及測(cè)量結(jié)果。

關(guān)于板級(jí)SMA頭連接器參數(shù)提取方法就介紹到這了,想了解更多與sma連接器相關(guān)的技術(shù)文檔,可以進(jìn)入我們的sma連接器產(chǎn)品專(zhuān)題:http://15800.cn/rf-connectors/sma-connectors/,在這個(gè)專(zhuān)題上您可以了解產(chǎn)品的性能屬性圖紙等信息,還可以閱讀技術(shù)文檔板塊中的文章。德索五金電子,專(zhuān)業(yè)的sma接頭制造商,至今已有十三年的歷史,產(chǎn)品通過(guò)ISO認(rèn)證,承諾一年質(zhì)保。

您對(duì)于sma頭功率容量知道多少,如果您想了解sma頭的功率容量想相關(guān)知識(shí),看完這篇稿子就應(yīng)該差不多了。德索博客頻道,每周有工防師固定更新一些專(zhuān)業(yè)文章,感興趣的話可前往查閱,地址:http://15800.cn/news/。

同軸電纜/接頭功率處理是一個(gè)復(fù)雜的課題,但它可以分解成兩種現(xiàn)象。高峰值功率會(huì)導(dǎo)致電弧引起的故障,而高平均功率會(huì)導(dǎo)致由于熱導(dǎo)致的故障。

射頻接頭的功率承受與尺寸和材料有關(guān),一般不能直接計(jì)算。同一種接頭,使用材料不同,功率承受也不一樣。

一般來(lái)說(shuō),接頭的功率承受隨信號(hào)頻率變高而降低。對(duì)同一頻率的射頻信號(hào),尺寸大的接頭的功率承受大。比如一般的SMA接頭,在2GHz的功率承受約為500W,在18GHz下的功率承受不到100W。BMA和SMA差不多,N接頭的功率承受約為SMA的3-4倍。以上所述功率承受指連續(xù)波功率。如入射功率為脈沖則功率承受還要高些。注意如果傳輸過(guò)程的匹配不好,駐波過(guò)大,則接頭上承受的功率有可能大于入射功率。一般為安全起見(jiàn),在接頭上加載的功率不應(yīng)超過(guò)其極限功率的1/2。

Peak power handling

This section was greatly improved for August 2017.

Power handling of air coax is a topic that is related to atmospheric breakdown.

Once breakdown occurs, a short circuit is provided across the coax, and Hell breaks loose.

Arcing is caused when the electric field E exceeds a critical value which we will denote Ed for electric field at discharge. In air, the critical field is about 1,000,000 volts/meter, in PTFE it is raised to about 100,000,000. These numbers are approximate, there’s no sense trying to be exact in calculating breakdown, just be sure you avoid it by an order of magnitude or more and you’ll have little to worry about.

The electric field of a coaxial transmission line varies as a function of position along the radial line from the outer conductor to the inner conductor (denoted “ρ” in the radial coordinate system). You’d have to use calculus to derive this, but we just looked it up in Pozar’s Microwave Engineering.

Here, “b” is D/2 and “a” is d/2, the radii of the outer and inner conductors. The peak E-field obviously occurs right at the surface of the center conductor. If this isn’t obvious to you, consider becoming a program manager!

Rearranging the equation for the maximum peak voltage when breakdown occurs,

For fixed “b”, the magic ratio of b/a for highest voltage handling turns out to be exactly “e”, or 2.718… you can prove this easily by taking the derivative of the above equation and setting it to zero (ewww, calculus!) Note that the magic b/a=e ratio for maximum voltage does not change when dielectric is introduced into the coax.

Now, let’s recall a shortcut equation for coax impedance… the “60” in the equation is a close approximation of η0 (the impedance of free space, ~377 ohms) divided by pi. The equation is accurate to at least three decimal places.

At the max voltage condition, ln(b/a)=ln(e)=1. Thus the impedance of air coax that can handle the highest voltage is 60 ohms and the impedance of any coax with any dielectric that can handle the most voltage is 60/SQRT(ER).

The peak power you can put into a coax under well-matched conditions (low VSWR) is calculated from the peak voltage it can withstand:

The 2 in the denominator is necessary because we were considering peak voltage, not RMS.

Plugging the Z0 equation into the Pmax equation yields:

Taking the derivative with respect to “a” and setting it to zero, yields a different magic ratio for maximum power: (b/a) for max power=e^0.5, as opposed to (b/a)=e^1 for maximum voltage. Using the maximum power b/a ratio, you will find that impedance for maximum power is 30/SQRT(ER). Thus, for air coax, Z0=30 ohms optimum for power. For PTFE-filled cables (ER=2.2), Z0 is 20.2 ohms for maximum power.

Now that we have the final equation for maximum peak power handling of coax, we are ready to do some analysis. Remember that this result is only true for a matched load. If you accidentally broke a connection to a high-power transmitter, you’d see a very high VSWR, in that case the peak voltage could double. If you need to consider this type of mishap, you want to further de-rate your power handling by 6 dB.

Now let’s look at some coax examples… how about the air dielectric 50-ohm connectors? The breakdown strength of air 3,300,000 volts/meter according to Wikipedia, but that is at “dry air” at standard temperature and pressure, between spherical electrodes. Let’s use 1,000,000 volts/meter.

How about PTFE-filled coax? The breakdown field strength of PTFE is about 10,000,000 volts per meter! So “049” cable (0.049 inches “D”, 0.015 inches “d”) can withstand 2260 volts and pass almost 50,000 watts peak. This seems to good to be true, doesn’t it? It is. The problem is that with voltage breakdown, the limitation of the weakest link in the chain is what you need to focus on. Your semi-rigid cable might be able to pass thousands of watts, but as soon as that signal crosses a path where the PTFE dielectric fill is interrupted by air, it will spark. At the end of the cable, where the connector is soldered on, there is surely going to be a gap in the dielectric. You need to revise the calculation for air dielectric, in which case you’ll see 256 volts is the maximum voltage, 358 watts is the maximum power into a good load, and 89 watts is the maximum into an unmatched load. Note that at this interface the coax presents 71 ohms impedance.

Before we move on to average power handling of coax, let’s look at power handing as a function of line impedance for air coax, which is part of the “coax compromise” that led to the fifty ohm standard. If you allow the center diameter freedom to move away from 50 ohms, you’ll see that maximum peak power handling occurs at ~30 ohms.

By the way, if anyone wants a copy the spreadsheet that generated this curve, just ask. Eventually we will put it into our download area, it still needs some clean up and comments…

New for August 2017: additional thoughts on this. Peak power handling of air coax may not be at 30 ohms, if you consider another limitation. Suppose you are operating very close to the cut-off of the unwanted TE11 mode. Heck, let’s assume you want to operate exactly at TE11 cut-off. TE11 cuts off when (b+a)*pi is equal to operating wavelength. To cut to the punch line, at TE11 cut-off, 44 ohms carries the most power. You can find this fun fact and many more in Introduction to Microwaves by Gershon J. Wheeler, dating back to 1963.

For September 2017, we created a new page and posted the math behind the 44 ohm absolute maximum peak power handling calculation, it included two solutions: one is brute force, the other is elegant. At least they agree!

Average power handling

Average power causes failure due to heat, as opposed to arcing. Cable vendors provide some guidance on average power handling, but there is a lot of voodoo involved. Basically, you don’t want the center conductor to heat up so much that it compromises the integrity of the cable. In the old days, cable vendors might have derived power handling ratings experimentally.

The dissipated power per length is the variable you need to consider, and you will need to note that dissipation is a function of frequency, with the metal loss term being proportional to SQRT(f). Thus, a cable that can handle 100 watts at 4 GHz is only good for 50 watts at 16 GHz.

You must consider how the cable is cooled, i.e. is there forced air, convection, conduction and/or radiation? What is the air temperature? (It can be much higher than room temperature if it is inside a housing or chassis).

If average power handling is a concern, we are going to recommend that you (or someone who knows what they are doing) perform a thermal analysis using finite-element techniques. If anyone has an example average power handling study, please sent it!

本文由德索五金電子運(yùn)營(yíng)團(tuán)隊(duì)編輯整理,文章來(lái)源于網(wǎng)絡(luò),如有侵權(quán),請(qǐng)及時(shí)聯(lián)系我們,進(jìn)行刪除。若需采購(gòu)sma連接器相關(guān)產(chǎn)品,請(qǐng)撥打我們的熱線電話:0769-81153906,專(zhuān)業(yè)工防師輔助您的采購(gòu)工作。德索五金電子,是一家主做射頻連接器的廠家,有著十三年的歷史,產(chǎn)品均通過(guò)了ISO認(rèn)證,符合國(guó)際上的環(huán)保要求,一年內(nèi)可享受免費(fèi)質(zhì)保的服務(wù),歡迎前來(lái)采購(gòu)。

本文來(lái)源:http://15800.cn/6188.html

在下文中,德索五金電子工防師將會(huì)為您介紹一下無(wú)線路由器改sma頭-極貳路由改裝SMA接口換天線的相關(guān)知識(shí),輕松幾步,您便會(huì)知道如何操作。如需采購(gòu)sma系列產(chǎn)品,撥打電話:0769-81153906。

一般而言,新極貳、極三(無(wú)線路由器)自帶的天線增益dbi較小且不可更換天線,接受性能受到約束,應(yīng)用場(chǎng)景受到限制。在日常應(yīng)用中我們需要增加無(wú)線路由的天線增益,或者使用定向天線以獲得更遠(yuǎn)、更穩(wěn)定的傳輸,這一且都要從改路由SMA接口,可拆天線開(kāi)始。

  工具/原料

新極貳路由器(或者其他無(wú)線路由)

6dbi無(wú)線天線兩根,可根據(jù)自己使用情況選擇天線

ipx-sma線兩根

螺絲刀

膠卡片

  第一步:拆開(kāi)路由

1

將需要使用到的工具和原料準(zhǔn)備好,拿起螺絲刀拆開(kāi)機(jī)器,注意把無(wú)線路由的天線放倒好拆,此路由為三角型螺絲孔,我是自己磨了一把螺絲刀。

 

 

 

 

  2

拆開(kāi)所有螺絲把擋板往外拉,整個(gè)板子就出來(lái)了。

極貳、極三都是 ipx轉(zhuǎn)SMA接口

用手指甲捏住直接就可以拔出來(lái)。

 

 

 

 

END

 

  第二步,換SMA接口

1

如果遇到路由器是焊接線的,把原天線的連接線剪斷一會(huì)兒手工接上就行了。

2

極貳是ipx的接口可以直接拔出來(lái)

 

 

 

 

3

取下原有天線,天線是中空的用力就可以完整取出來(lái),天線基座也是一樣用里壓一下就能取下來(lái)。

 

 

 

 

END

 

  第三步,安裝新SMA接口

1

在安裝新口的時(shí)候,發(fā)現(xiàn)SMA的墊片太小了,要自己用膠卡做墊片。

 

 

 

 

 

 

 

 

2

安裝ipx-SMA接頭到檔板上

 

 

3

把擋板靠近路由板子,連接ipx接頭,要對(duì)準(zhǔn)用力壓一下,有“啪”的聲音就緊了。

 

 

4

如果遇到是焊接線的,把兩條線剪的連接線直接接到一起就可以了。

 

 

 

  5

把圖中的主板、擋板進(jìn)行還原,然后上螺絲和天線

 

 

 

 

 

 

END

  第四步,開(kāi)機(jī)測(cè)試信號(hào)

1

換上準(zhǔn)備好的天線開(kāi)機(jī)測(cè)試,(可以連接不同增益的天線)。

 

 

 

 

2

親們,可以在筆記本上安裝類(lèi)似wirelessmon相關(guān)的軟件。

看RSSI 這欄,數(shù)字是負(fù)越小,信號(hào)越好,別看錯(cuò)額。

 

END

  最后,注意事項(xiàng)提醒

注意最好帶手套,不要讓汗留到路由板上

關(guān)于無(wú)線路由器改sma頭-極貳路由改裝SMA接口換天線的內(nèi)容,就介紹到這了。了解德索sma接頭接口產(chǎn)品信息,點(diǎn)擊http://15800.cn/rf-connectors/sma-connectors/進(jìn)入查看詳情。德索五金電子,十三年的sma接頭接口生產(chǎn)經(jīng)驗(yàn),ISO認(rèn)證產(chǎn)品,符合國(guó)際環(huán)保要求,值得您的信賴(lài)!

本文來(lái)源:http://15800.cn/4174.html

關(guān)于sma接頭外螺內(nèi)孔怎么制作,你知道嗎?下面,德索五金電子工防師,將會(huì)告訴您sma接頭外螺內(nèi)孔的制作方法,讓你不用在為這個(gè)問(wèn)題困擾。正所謂,自己動(dòng)手,豐衣足食,學(xué)會(huì)以后,就再也不需要請(qǐng)教他人如何制作sma接頭了。

用于制作射頻接頭,所用工具如下

工具/原料

專(zhuān)業(yè)壓線鉗,電烙鐵,剝線鉗,鑷子,熱縮管,同軸電纜

方法/步驟

準(zhǔn)備線材。從左至右線材:國(guó)產(chǎn)同軸電纜RG316,熱縮管,壓線套,SMA外螺內(nèi)孔母頭,小針。

先將熱縮管、壓管套住屏蔽線,剝?nèi)テ帘尉€外圍的塑料套,保證留出線長(zhǎng)13mm,然后用鑷子將屏蔽層捋順,屏蔽層留線7mm,最后剝?nèi)ソ^緣層3mm。

將SMA頭的針套上,上錫(錫不要上太多),能固定小針與芯線就可以。然后將SMA頭、壓管套上,用壓線鉗將壓管壓好,最后套上熱縮管,用風(fēng)槍吹好。

 

閱讀完上述內(nèi)容之后,您對(duì)于“SMA接頭外螺內(nèi)孔怎么制作”應(yīng)該有個(gè)基本認(rèn)識(shí)了,現(xiàn)在您應(yīng)該可以成功制作一個(gè)sma接頭了吧。如果您有更多關(guān)于sma接頭的問(wèn)題,可以向我們發(fā)送郵件:dosin2005@dosin-china.com,我們會(huì)在第一時(shí)間幫解答您的問(wèn)題。采購(gòu)sma接頭,選德索五金電子,專(zhuān)業(yè)的sma接頭生產(chǎn)廠家,十三年生產(chǎn)經(jīng)驗(yàn),ISO認(rèn)證,一年質(zhì)保,值得信賴(lài)!

sma接頭產(chǎn)品頻道:http://15800.cn/rf-connectors/sma-connectors/