1 Gabatarwa

Buga kwamiti na kewaye (PCB) mutuncin siginar ya kasance batu mai zafi a cikin ‘yan shekarun nan. An sami rahotannin bincike da yawa na cikin gida akan nazarin abubuwan da suka shafi mutuncin siginar PCB, amma gwajin asarar siginar Gabatarwa ga yanayin fasaha na yanzu ba kasafai bane.

Tushen asarar siginar watsawa ta PCB shine asarar madugu da asarar dielectric na kayan, kuma hakan yana shafar abubuwa kamar juriya na jan ƙarfe, rashin ƙarfi na jan ƙarfe, hasara na radiation, rashin daidaituwa na impedance, da crosstalk. A cikin sarkar samar da kayayyaki, alamomin yarda na masana’antun jan karfe clad laminate (CCL) masana’antun da masu kera PCB suna amfani da ƙarancin dielectric akai-akai da asarar dielectric; yayin da masu nuna alama tsakanin masana’antun PCB da tashoshi sukan yi amfani da rashin ƙarfi da asara, kamar yadda aka nuna a hoto na 1.

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Don ƙirar PCB mai sauri da amfani, yadda za a auna saurin siginar siginar layukan watsa PCB yana da mahimmanci ga saitin sigogin ƙirar PCB, lalata kwaikwaiyo, da sarrafa tsarin samarwa.

2. Halin halin yanzu na fasahar gwajin hasarar PCB

Hanyoyin gwajin siginar PCB da ake amfani da su a halin yanzu a cikin masana’antu an rarraba su daga kayan aikin da aka yi amfani da su, kuma ana iya raba su zuwa rukuni biyu: dangane da yankin lokaci ko kuma dangane da yankin mita. Kayan aikin gwajin yanki na lokaci shine Reflectometry Domain Reflectometry (TDR) ko mitar watsa yankin lokaci (TimeDomain Transmission, TDT); kayan aikin gwajin mita na yanki shine Vector Network Analyzer (VNA). A cikin ƙayyadaddun gwajin IPC-TM650, ana ba da shawarar hanyoyin gwaji guda biyar don gwajin asarar siginar PCB: Hanyar yanki ta mita, ingantacciyar hanyar bandwidth, hanyar bugun jini mai ƙarfi, gajeriyar hanyar yaduwar bugun jini, hanyar asara daban-daban TDR mai ƙarewa ɗaya.

2.1 Hanyar yanki ta mita

Hanyar Domain Frequency galibi yana amfani da mai nazarin hanyar sadarwa na vector don auna ma’aunin S-parameters na layin watsawa, yana karanta ƙimar asara kai tsaye, sannan yana amfani da madaidaiciyar gangara na matsakaicin asarar shigarwa a cikin takamaiman kewayon mitar (kamar 1 GHz ~ 5 GHz) Auna fasfo/ gazawar allon.

Bambanci a cikin daidaiton ma’auni na hanyar yankin mitar ya fito ne daga hanyar daidaitawa. Dangane da hanyoyin daidaitawa daban-daban, ana iya raba shi zuwa SLOT (Short-Line-Open-Thru), MulTI-Line TRL (Thru-Reflect-Line) da Ecal (Electronic calibraTion) hanyoyin daidaitawar lantarki.

SLOT yawanci ana ɗaukarsa azaman daidaitaccen hanyar daidaitawa [5]. Samfurin daidaitawa yana da sigogin kuskure 12. An ƙaddara daidaiton daidaitawa na hanyar SLOT ta sassan daidaitawa. Ana ba da ɓangarorin madaidaicin madaidaicin ma’auni ta masana’antun kayan aunawa, amma sassan daidaitawa suna da tsada , Kuma gabaɗaya kawai sun dace da yanayin coaxial, daidaitawa yana ɗaukar lokaci kuma yana ƙaruwa ta hanyar geometric yayin da adadin ma’auni ya karu.

Hanyar MulTI-Line TRL ana amfani dashi galibi don ma’aunin daidaitawa mara coaxial [6]. Dangane da kayan aikin layin da aka yi amfani da shi da mai amfani da gwajin gwajin, an tsara sassan daidaitawa na TRL da kuma samar da su, kamar yadda aka nuna a cikin Hoto 2. Kodayake Multi-Line TRL ya fi sauƙi don tsarawa da ƙera fiye da SLOT, lokacin daidaitawa na Hanyar TRL mai-Layi mai yawa kuma tana ƙaruwa da geometrically tare da haɓaka yawan adadin ma’auni.

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Don magance matsalar daidaitawa na cin lokaci, masana’antun kayan aikin auna sun gabatar da hanyar daidaitawa ta Ecal [7]. Ecal shine ma’aunin watsawa. An ƙayyade daidaiton daidaitawa ta asali ta sassa na daidaitawa. A lokaci guda, ana gwada kwanciyar hankali na kebul na gwaji da kwafi na na’urar gwajin gwaji. Algorithm na interpolation na aiki da mitar gwaji shima yana da tasiri akan daidaiton gwajin. Gabaɗaya, yi amfani da na’urar daidaitawa ta lantarki don daidaita yanayin nuni zuwa ƙarshen kebul ɗin gwaji, sannan yi amfani da hanyar cirewa don rama tsawon kebul na na’urar. Kamar yadda aka nuna a hoto na 3.

Nazarin Tasirin Abubuwan Tasirin Mutuncin Siginar PCB Printed Board

Don samun asarar shigar da layin watsawa daban a matsayin misali, ana nuna kwatancen hanyoyin daidaitawa guda uku a cikin Table 1.

2.2 Ingantacciyar hanyar bandwidth

Bandwidth mai inganci (EBW) shine ma’auni mai inganci na asarar layin watsawa α cikin ma’ana mai mahimmanci. Ba zai iya ba da ƙima mai ƙima na asarar sakawa ba, amma yana ba da siga da ake kira EBW. Hanyar bandwidth mai tasiri ita ce watsa siginar mataki tare da takamaiman lokacin tashi zuwa layin watsawa ta hanyar TDR, auna matsakaicin matsakaicin lokacin hawan bayan an haɗa kayan TDR da DUT, kuma ƙayyade shi azaman asarar hasara, a cikin MV. /s. Daidai daidai, Abin da ya ƙayyade shine dangi jimlar hasara, wanda za’a iya amfani dashi don gano canje-canje a cikin asarar layin watsawa daga saman zuwa saman ko Layer zuwa Layer [8]. Tun da za a iya auna matsakaicin gangara kai tsaye daga kayan aiki, ana amfani da ingantaccen hanyar bandwidth sau da yawa don gwajin samar da taro na allunan kewayawa da aka buga. Ana nuna zane-zane na gwajin EBW a Hoto na 4.

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2.3 Tushen makamashin bugun jini

Tushen ImPulse Energy (RIE) yawanci yana amfani da kayan aikin TDR don samun nau’ikan raƙuman ruwa na TDR na layin asarar tunani da layin watsa gwaji, sannan aiwatar da sarrafa sigina akan siginar TDR. Ana nuna tsarin gwajin RIE a hoto na 5:

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2.4 Gajerun hanyoyin yada bugun jini

Hanyar ƙwaƙƙwaran ƙwayar bugun jini (Short Pulse Propagation, wanda ake kira SPP) ƙa’idar gwajin ita ce auna layin watsawa guda biyu masu tsayi daban-daban, kamar 30 mm da 100 mm, da kuma cire ma’aunin attenuation coefficient da lokaci ta hanyar auna bambanci tsakanin su biyun. tsawon layin watsawa. Constant, kamar yadda aka nuna a hoto 6. Yin amfani da wannan hanya na iya rage tasirin masu haɗawa, igiyoyi, bincike, da daidaiton oscilloscope. Idan manyan kayan aikin TDR da IFN (Impulse Forming Network) ake amfani da su, mitar gwajin na iya kaiwa 40 GHz.

2.5 Hanyar asara bambancin TDR mai ƙarewa ɗaya

TDR mai Ƙarshen Ƙarshe zuwa Asarar Saka Bambanci (SET2DIL) ya bambanta da gwajin asara na daban ta amfani da VNA mai tashar jiragen ruwa 4. Wannan hanyar tana amfani da kayan aikin TDR mai tashar jiragen ruwa guda biyu don watsa martanin matakin TDR zuwa layin watsawa daban-daban, Ƙarshen layin watsawa daban-daban yana gajarta, kamar yadda aka nuna a cikin Hoto 7. Matsakaicin ƙimar mitar ta hanyar SET2DIL shine 2 GHz ~ 12 GHz, kuma daidaiton auna ya fi shafar rashin daidaituwa na kebul na gwaji da rashin daidaituwa na DUT. Amfanin hanyar SET2DIL shine cewa babu buƙatar amfani da VNA mai tashar jiragen ruwa 4 mai tsada da sassan daidaitawa. Tsawon layin watsawar sashin da aka gwada shine rabin hanyar VNA. Sashin daidaitawa yana da tsari mai sauƙi kuma lokacin daidaitawa yana raguwa sosai. Ya dace sosai don masana’antar PCB. Gwajin batch, kamar yadda aka nuna a hoto na 8.

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3 Gwajin kayan aiki da sakamakon gwaji

SET2DIL gwajin jirgin, SPP gwajin jirgin da Multi-Line TRL gwajin jirgin da aka yi amfani da CCL tare da dielectric akai na 3.8, dielectric asarar 0.008, da kuma RTF jan karfe foil; kayan gwaji sune DSA8300 samfurin oscilloscope da E5071C vector network analyzer; Asarar shigar daban-daban na kowace hanya Ana nuna sakamakon gwajin a cikin Tebura 2.

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Kammalallen 4

Wannan labarin yafi gabatar da hanyoyin auna asarar siginar PCB da yawa da ake amfani da su a cikin masana’antar. Saboda hanyoyin gwaji daban-daban da aka yi amfani da su, ƙimar asarar shigar da aka auna sun bambanta, kuma ba za a iya kwatanta sakamakon gwajin kai tsaye a kwance ba. Sabili da haka, yakamata a zaɓi fasahar gwajin hasarar siginar da ta dace bisa ga fa’ida da iyakancewar hanyoyin fasaha daban-daban, kuma a haɗa su da bukatun kansu.