Umklamo we-PCB wesixhumi se-SMA: Ukukhweza kanye nokuqaliswa kwe-50-Ohm

Isixhumi se-SMA (inguqulo ye-SubMiniature A) siyisixhumi se-RF coaxial esinezintambo esingu-50-ohm esisetshenziswa kabanzi ukuletha amasignali e-radio-frequency ngaphakathi nangaphandle kwe-PCB, ngokuvamile esingasetshenziswa cishe ku-18 GHz. Ukusilungisa kahle ebhodini akubalulekile kangako ngesixhumi kodwa kuningi mayelana nokuqaliswa, i-geometry yezinyawo ethwala isignali kusukela ku-coax iye ku-trace ye-PCB engu-50-ohm ngaphandle kokubonakaliswa. Lo mhlahlandlela uhlanganisa izinhlobo ze-SMA, izinhlobo zokufakwa kwe-PCB, i-geometry yokuqaliswa ebeka i-impedance, indlela yokufanisa i-trace nezinto, kanye nendlela isixhumi esihlanganiswa ngayo.

Kuyini Isixhumi se-SMA?

I-SMA ingenye yezixhumi ze-RF ezivame kakhulu. Isebenzisa i-screw-thread coupling kanye ne-50-ohm coaxial geometry, okwenza iqine futhi iphindaphindeke ekuxhumeni izintambo, ama-antenna, kanye nezinsimbi ebhodini.

Izici ezibalulekile

• Impedance engu-50-ohm, ukufanisa izinhlelo ze-RF ezivamile kanye nekhebula le-coaxial.
• Ukuhlanganiswa okunentambo, okunikeza uxhumano oluphephile nolubekezelela ukudlidliza.
• Uhlu lwamaphutha ngokuvamile cishe ku-18 GHz, kanti izinguqulo ezinembile zifinyelela phezulu.

Ngenxa yokuthi ithwala i-RF, uxhumano lwe-SMA lufana nokushintshela ebhodini. Lokho kwenza kube yinkinga yokuqina kwesignali kanye nokwakheka komshini, okuhlobene kakhulu nokukhathazeka okubanzi komklamo wesivinini esikhulu kanye ne-RF.

Izinhlobo Zezixhumi ze-SMA kanye ne-RP-SMA

Akuwona wonke ama-connector “e-SMA” ahambisana, ngakho-ke ukuhlonza uhlobo oluqondile kubalulekile.

I-RP-SMA uhlobo oluvame ukukhuba abantu. Lwethulwa kakhulu ngenxa yezizathu zomthetho emikhiqizweni engenantambo yabathengi, futhi yize ibukeka njenge-SMA, ukuxhumana kwayo okuphakathi okushintshiwe kusho ukuthi ngeke ihlangane kahle ne-SMA ejwayelekile. Njalo qinisekisa i-standard vs reverse-polarity, kanye nobulili, ngokumelene ne-antenna noma ikhebula ohlose ukulisebenzisa ngaphambi kokuthatha isinyathelo.

Izinketho Zokufaka i-SMA PCB

Izixhumi ze-SMA zinamathela ebhodini ngezindlela eziningana, futhi ukukhetha kuthinta kokubili ukuqaliswa kanye nobuchwepheshe.

• Ukuqaliswa komngcele. Ifakwa emaphethelweni ebhodi lapho iphini eliphakathi lifika khona endaweni engaphandle; ithandwa kakhulu ekushintsheni okuhlanzekile, okulawulwayo kwe-impedance.
• Umgodi odlulayo oqonde phezulu/owokuqala. Iphini eliphakathi lidlula ebhodini liye ku-via noma i-pad; lilula futhi liqinile ngokwemishini.
• Ukukhweza okungaphezulu. Ama-solders kuma-surface pads, afanele ukuhlanganiswa kokugeleza kabusha kanye namaphrofayili aphansi.

Ukuqaliswa komngcele kuvame ukuthandwa kumaza aphezulu ngoba isignali ihlala ku-microstrip engaphezulu ngaphandle kokushintsha kwebhodi elidlulayo okungangeza ukungaqhubeki. Izitayela zokungena ngembobo kanye nezitayela zokufaka amaphaneli zivame lapho amandla omshini noma uxhumano lwe-chassis lubalulekile. Isitayela sokufaka kumele sinqunywe kanye nomklamo wokuqalisa, hhayi ngemuva.

Ukuqaliswa Komphetho vs Ukufakwa Kwembobo Ethrough vs Ukufakwa Komphezulu

Isitayela sokufaka sakha kokubili ukuguquka kwe-RF kanye nendlela isixhumi esisingatha ngayo ukucindezeleka komshini.

Ukuze kube noshintsho oluhlanzekile kakhulu lwemvamisa ephezulu, ukuqaliswa komphetho kugcina isignali ku-microstrip engaphezulu ngaphandle kwesinyathelo esidlula ebhodini. Izitayela ze-through-hole kanye nephaneli zishintsha ukusebenza kwe-RF okuncane ngamandla omshini noma uxhumano lwe-chassis. Kungakhathaliseki ukuthi yisiphi isitayela, indawo yokubeka kufanele ifane nengxenye kanye ne-stackup eqondile, yingakho ukukhetha kokufaka kwenziwa kanye nokuqaliswa ngesikhathi sokuhlelwa kwesivinini esikhulu futhi kuqinisekiswe ngaphambi kokuhlanganiswa.

I-SMA Footprint kanye ne-Launch Geometry yama-Ohms angu-50

"Ukuqaliswa" yisifunda esincane lapho isixhumi se-coaxial sihlangana khona nomkhondo we-PCB, futhi yilapho ukusebenza okuningi kwe-SMA kunqunywa khona. Umgomo ukugcina i-impedance ku-50 ohms phakathi noshintsho ukuze isignali ingabonisi.

Indlela ethembeke kakhulu yokwenza lokhu kube yikho ukulandela umkhondo onconyiwe womkhiqizi wesixhumi, olungiselelwe i-stackup ethile yebhodi. Iphedi yesignali enkulu kakhulu yengeza amandla futhi yehlise i-impedance; ama-via angaphansi komhlaba angekho ashiya indlela yokubuya ingaqhubeki. Ezingxenyeni zokuqalisa ezinqenqemeni, ukuvumelanisa amaphedi ngqo nomngcele webhodi kuyingxenye yokuqaliswa. Lena imininingwane ebekwe ngendlela ehlelekile futhi eqashelwa ngesikhathi sokukhiqiza i-PCB , futhi ukuyibuyekeza kuwumsebenzi oyinhloko wokubuyekezwa komklamo.

Ukufanisa i-PCB Trace kanye nezinto ezibonakalayo

Ukuqalisa okuhle kumele kudluliselwe ku-trace eklanywe kahle engu-50-ohm, noma inzuzo ilahleka ngamamilimitha ambalwa.

Umugqa we-50-ohm

I-trace ngokuvamile iyi-microstrip noma i-waveguide ye-coplanar egxilile ububanzi bayo bubalwa kusukela ku-stackup, i-dielectric constant (Dk), ubukhulu be-dielectric, kanye nethusi. Ukuqaliswa kwesixhumi kumele kufane nalobu bubanzi be-trace, ngakho ukuqaliswa kanye nomugqa kuklanywe ndawonye njengendlela eyodwa engu-50-ohm.

Izinto ezisetshenziswa kumaza aphezulu

Emazameni aphezulu, i-laminate evamile ilahlekelwa isignali eningi kakhulu. Izinto ezilahlekelwa kancane ezine-Dk ephansi, ezinzile kanye ne-dissipation factor ephansi, kanye nethusi elibushelelezi, zikhawulela ukulahlekelwa kokufakwa. Yilapho amabhodi alahlekelwa kancane nezinto ezinikezelwe kumaza aphezulu zisiza khona, zivimbela ukuqaliswa kanye nokulandelela okuklanywe ngokucophelela ukuthi kungasuswa yi-substrate.

Ukushisela Nokufaka Isixhumi se-SMA

Isixhumi se-SMA sihlanganiswe njengezingxenye ezithile, kodwa futhi sinamandla okuhlangana aphindaphindwayo, ngakho-ke omakhenikha babalulekile.

• I-soldering. Izinguqulo zokunamathisela emaphethelweni kanye nezimbobo zokunamathisela ebusweni ziboshelwa esignalini kanye nasezimbobeni zomhlabathi; izinguqulo ezimbobo ezidlulayo ziboshelwa ebhodini.
• Amandla omshini. Ngenxa yokuthi ukugoqa ikhebula kusebenzisa i-torque futhi isixhumi sithatha imithwalo eseceleni, amajoyinti aqinile e-solder, futhi ngezinye izikhathi ukufaka amathebhu noma ihadiwe, yigcine iphephile.
• Ukucindezeleka nokuqondanisa. Ukuxhumana okuhle komhlabathi kanye nokunamathela okuqinile kuvimbela ukwethulwa ekushintsheni ngokuhamba kwesikhathi.

Emgqeni wokukhiqiza, lezi zixhumi zifakwa futhi zifakwe i-solder njengengxenye yokuhlanganiswa kwe-PCB, kugxilwe kokubili kumajoyinti e-RF kanye nokugcinwa kwemishini. Isixhumi esiphelele ngogesi kodwa esikhululekile ngokwemishini sizohluleka ukusebenza, ngakho-ke lezi zici ezimbili zakhiwe ndawonye.

Amaphutha Okuklama E-PCB Ejwayelekile ye-SMA

Izinkinga eziningi ze-SMA zivela ohlwini olufushane lwamaphutha angagwenywa.

• Ukusebenzisa umkhondo ojwayelekile esikhundleni sephethini yomhlaba elungisiwe yomkhiqizi ye-stackup yakho.
• Iphedi yesignali enkulu kakhulu, okwengeza i-capacitance futhi idonsa i-impedance engaphansi kwama-ohms angu-50.
• Akukho noma kuncane kakhulu ngocingo, ukushiya ukubuya komhlaba kungaqhubeki ngesikhathi sokwethulwa.
• I-Trace ayifani nama-ohms angu-50, noma ububanzi obungahlangabezani kahle nokuqaliswa.
• Izinto ezingalungile ngesivinini esiphezulu, ukuvumela i-substrate ibuse ukulahlekelwa.
• Ukudideka kwe-SMA kanye ne-RP-SMA, okuholela esixhumini esingeke sihlangane.

Ngayinye yalezi kulula ukuyivimbela ngesikhathi sokuklama futhi kubuhlungu ukuyilungisa ngemva kwalokho. Ukulandela ishidi ledatha lesixhumi, ukufanisa umkhondo nezinto, nokuqinisekisa okuhlukile kuguqula i-SMA isuke engozini ibe isixhumi esijwayelekile se-RF esiphindaphindwayo.

Isixhumi se-SMA ku-PCB siyaphumelela noma siyahluleka ekuqalisweni: indawo elungiselelwe umenzi, umkhondo ohambisanayo wama-ohm angu-50, umhlabathi oqinile ngocingo, kanye nezinto ezilahlekelwa kancane kumaza aphezulu. Qinisekisa uhlobo, klama ukuqaliswa bese uluhlanganisa ndawonye, ​​bese uluhlanganisa kahle. Ungafunda kabanzi mayelana ne-Highleap Electronics kanye namakhono ethu e-RF kanye ne-high-frequency.

imibuzo ejwayelekile ukubuzwa

Yini isixhumi se-SMA esisetshenziswa ku-PCB?

Kuyisixhumi se-coaxial esingu-50-ohm esinezintambo esisetshenziselwa ukuletha izimpawu ze-RF ebhodini nangaphandle kwalo, sixhuma ezintanjeni, kuma-antenna, kanye nemishini yokuhlola. Sivame ukufika ku-18 GHz. Ku-PCB, ingxenye ebalulekile ukuqaliswa, indawo eshintsha isignali isuke ku-coax iye ku-trace engu-50-ohm ngaphandle kokubonakaliswa.

Uyini umehluko phakathi kwe-SMA ne-RP-SMA?

I-RP-SMA (i-reverse-polarity SMA) ishintshanise ubulili bokuxhumana okuphakathi uma kuqhathaniswa ne-SMA ejwayelekile. Yethulwe kakhulu ngenxa yezizathu zomthetho emikhiqizweni engenantambo yabathengi. Nakuba ibukeka ifana, ngeke ihlangane kahle ne-SMA ejwayelekile, ngakho-ke kufanele ufanise uhlobo oluqondile kanye nobulili ne-antenna noma ikhebula lakho.

Yiluphi uhlobo lokufaka lwe-SMA okufanele ngilusebenzise?

Ukuqaliswa komphetho kuyathandwa kakhulu ngamaza aphezulu ngoba isignali ihlala ku-microstrip engaphezulu ngaphandle kokushintsha kwebhodi elidlulayo. Izinhlobo zokuqaliswa okuqondile noma okudlulela emgodleni zilula futhi ziqinile ngokomshini, futhi ukufakwa komphezulu kuhambisana nokuhlanganiswa kokugeleza kabusha. Khetha isitayela sokufaka kanye nomklamo wokuqaliswa kanye nezidingo zebhodi zomshini.

Kungani i-geometry yokuqalisa ibaluleke kangaka?

Ukuqaliswa yilapho isixhumi se-coaxial sihlangana khona nomkhondo we-PCB, futhi noma yisiphi isinyathelo sokungavumeli lapho sibonisa amandla e-RF. Iphedi yesiginali enobukhulu obufanele, umhlabathi ozungezile, uthango oluya ezindizeni zokubhekisela, kanye nokuvuleka okufanele kugcina ukuguquka ku-50 ohms. Ukulandela umkhondo onconywe ngumenzi we-stackup yakho kuyindlela ephephile kakhulu.

Yimuphi umkhondo nezinto okufanele i-SMA ixhumane nazo?

I-microstrip engu-50-ohm noma i-waveguide ye-coplanar egxiliwe ububanzi bayo bubalwa kusukela ku-stackup, i-dielectric constant, kanye nethusi, ehambisana nokuqaliswa kwesixhumi. Emafrikhwensini aphezulu, sebenzisa i-laminate elahlekelwa kancane, enemvamisa ephezulu ene-Dk ephansi, ezinzile kanye nethusi elibushelelezi ukuze unciphise ukulahlekelwa kokufakwa, noma i-substrate izohlehlisa ukuqaliswa okuhle.

Isixhumi se-SMA sigcinwa kanjani siphephile ngokomshini?

Ngenxa yokuthi ukuxhumanisa ikhebula kusebenzisa i-torque kanye nemithwalo eseceleni, isixhumi sidinga amajoyinti aqinile e-solder kuma-signal kanye nama-ground pad aso, futhi ngezinye izikhathi ukufaka amathebhu noma ihadiwe. Ukuxhumana okuhle komhlabathi kanye nokunamathela okuqinile nakho kuvimbela ukuqaliswa ukuthi kushintshe ngokuhamba kwesikhathi. Isixhumi esiphelele ngogesi kodwa esikhululekile ngokomshini sizohluleka ukusebenza.

Yiliphi iphutha elivame kakhulu lokuklama i-SMA?

Ukusebenzisa unyawo olujwayelekile esikhundleni sephethini yomhlaba elungisiwe yomkhiqizi wesixhumi, kuvame ukuhlanganiswa nephedi yesignali enkulu kakhulu kanye nocingo olungekho. Lokhu kudala ukungaqhubeki kwe-impedance ekuqalisweni. Ukulandela unyawo lwedatha, ukufanisa umkhondo wama-ohm angu-50, nokuqinisekisa i-SMA vs. RP-SMA kuvimbela izinkinga eziningi.

Yiluphi ububanzi bemvamisa olusekelwa yisixhumi se-SMA?

Izixhumi ze-SMA ezijwayelekile zivame ukusetshenziswa kufika ku-18 GHz, futhi izinguqulo ezinembile emndenini wosayizi ofanayo zifinyelela phezulu. Umkhawulo ophezulu osebenzayo ebhodini uncike kakhulu ekwakhiweni kokuqaliswa, umkhondo, kanye nezinto; ukuqaliswa okubi noma i-laminate elahlekile yehlisa ukusebenza kahle ngaphansi kakhulu kwesilinganiso sesixhumi.

Ngingakwazi yini ukudayisa isixhumi se-SMA ngesandla?

Yebo, izixhumi ze-SMA ezifakwa emaphethelweni kanye nezingena embobeni zivame ukushintshwa ngesandla, kugxilwe ekuhlanganisweni okuhlanzekile ephinini eliphakathi kanye nokuxhumana okuqinile phansi. Izinguqulo zokushintshwa komhlaba zingashintshwa noma zishiswe ngesandla. Imfuneko enkulu iwumshini: amalunga kumele amelane ne-torque kanye nomthwalo ohlangothini wokuxhuma ikhebula.

Ingabe izinto ze-PCB ziyakuthinta ukuxhumana kwe-SMA?

Ngokuphawulekayo kuma-frequency aphezulu. I-trace impedance ibalwa kusukela ku-dielectric constant kanye nobukhulu be-laminate, futhi ukulahleka kwesiginali kuncike ku-dissipation factor kanye ne-copper roughness. Izinto ezilahleka kancane, ezivame kakhulu zigcina ukulahleka kokufakwa kuphansi, ngakho-ke i-substrate iyingxenye yomklamo we-RF, hhayi nje isithwali semishini.