Ulwakhiwo lwe-laminate yebhodi yeRF kunye neemfuno zocingo

Ukongeza kwi-impedance yomgca wesignali yeRF, ulwakhiwo olulaminethiweyo lwe-RF PCB enye ibhodi nayo kufuneka ithathele ingqalelo imiba efana nokutshatyalaliswa kobushushu, okwangoku, izixhobo, i-EMC, ubume kunye nefuthe lolusu. Ngokuqhelekileyo sisekubekweni kunye nokupakishwa kweebhodi ezininzi eziprintiweyo. Landela imigaqo esisiseko:

 

A) Umaleko ngamnye weRF PCB ugqunywe ngummandla omkhulu ngaphandle kwenqwelomoya yombane. Amaleko angaphezulu nasezantsi ameleneyo omaleko wocingo lweRF kufuneka abe ziindiza eziphantsi.

Nokuba yibhodi edityanisiweyo ye-analog yedijithali, inxalenye yedijithali inokuba nenqwelomoya yamandla, kodwa indawo yeRF kusafuneka ihlangabezane nemfuneko yendawo enkulu yokugada kumgangatho ngamnye.

B) Kwiphaneli ephindwe kabini yeRF, umaleko ongaphezulu ngumaleko wesiginali, kwaye umaleko ongezantsi yinqwelomoya ephantsi.

Ibhodi enye yeRF enemigangatho emine, umaleko ongaphezulu ngumaleko wesiginali, owesibini nowesine ziindiza eziphantsi komhlaba, kwaye owesithathu ngowomandla kunye nemigca yolawulo. Kwiimeko ezikhethekileyo, ezinye iilayini zesiginali yeRF zingasetyenziswa kumaleko wesithathu. Iingqimba ezininzi zeebhodi zeRF, njalo njalo.
C) Kwi-backplane ye-RF, umaleko ongaphezulu nophantsi womgangatho womibini usemhlabeni. Ukuze kuncitshiswe i-impedance discontinuity ebangelwa yi-vias kunye nezihlanganisi, i-second, eyesithathu, yesine, kunye neyesihlanu umaleko usebenzisa imiqondiso yedijithali.

Ezinye iileya ze-stripline kumphezulu ongezantsi zizo zonke iileya zesignali ezisezantsi. Ngokufanayo, iileya ezimbini ezikufutshane zomaleko wophawu lweRF kufuneka zibe phantsi, kwaye umaleko ngamnye kufuneka ugqunywe ngummandla omkhulu.

D) Kumandla aphezulu, iibhodi zeRF eziphezulu zangoku, ikhonkco eliphambili leRF kufuneka libekwe kumaleko aphezulu kwaye liqhagamshelwe ngomgca obanzi wemicrostrip.

Oku kulungelelaniswa nokutshatyalaliswa kobushushu kunye nokulahlekelwa kwamandla, ukunciphisa iimpazamo ze-wire corrosion.

E) Indiza yamandla yecandelo ledijithali kufuneka isondele kwinqwelomoya kwaye ihlelwe ngaphantsi kwendiza yomhlaba.

Ngale ndlela, i-capacitance phakathi kweepleyiti ezimbini zetsimbi ingasetyenziswa njenge-capacitor egudileyo yonikezelo lwamandla, kwaye kwangaxeshanye, inqwelomoya esemhlabeni inokukhusela i-radiation current esasazwa kwinqwelomoya yamandla.

Indlela ethile yokupakisha kunye neemfuno zokwahlulwa kwenqwelomoya zinokubhekisa kwi-"20050818 Printed Board Board Specification-EMC Requirements" ebhengezwe liSebe loYilo lwe-EDA, kwaye imigangatho ye-intanethi iya kuphumelela.

2
Iimfuno zocingo lwebhodi yeRF
2.1 Ikona

Ukuba ulandelelwano lwe-RF luhamba ngee-engile ezichanekileyo, ububanzi bomgca obusebenzayo kwiikona buya kunyuka, kwaye uthintelo luya kuyeka kwaye lubangele ukubonakaliswa. Ngoko ke, kuyimfuneko ukujongana neekona, ngokukodwa kwiindlela ezimbini: ukusika ikona kunye nokujikeleza.

(1) Ikona esikiweyo ilungele ukugoba okuncinci, kwaye i-frequency esebenzayo yekona esikiweyo inokufikelela kwi-10GHz.

 

 

(2) Iradiyasi ye-arc angle kufuneka ibe nkulu ngokwaneleyo. Ngokubanzi, qinisekisa: R>3W.

2.2 Iingcingo zeMicrostrip

Umaleko ophezulu we-PCB uthwala umqondiso we-RF, kwaye umaleko wenqwelo-moya phantsi komqondiso we-RF kufuneka ube yinqwelomoya ephantsi epheleleyo ukuze yenze ulwakhiwo lomgca we-microstrip. Ukuqinisekisa ingqibelelo yesakhiwo somgca we-microstrip, kukho ezi mfuno zilandelayo:

(1) Imiphetho emacaleni omabini omgca wemicrostrip kufuneka ubuncinane ibe yi-3W ububanzi ukusuka kumda wenqwelomoya esezantsi. Kwaye kuluhlu lwe-3W, akufuneki kubekho ii-vias ezingenasiseko.

(2) Umgama phakathi komgca we-microstrip kunye nodonga olukhuselayo kufuneka ugcinwe ngaphezu kwe-2W. (Qaphela: W bububanzi bomgca).

(3) Imigca ye-microstrip engadityaniswanga kwinqanaba elifanayo kufuneka iphathwe ngesikhumba sobhedu emhlabeni kunye ne-vias yomhlaba kufuneka yongezwe kwisikhumba sobhedu emhlabeni. Isithuba somngxuma singaphantsi kwe-λ/20, kwaye zicwangciswe ngokulinganayo.

Umda we-foil yobhedu yomhlaba kufuneka ube mfiliba, ube tyaba, kwaye akukho burrs ezibukhali. Kunconywa ukuba umgca wobhedu owenziwe phantsi komhlaba mkhulu okanye ulingana nobubanzi be-1.5W okanye i-3H ukusuka kumda we-microstrip line, kwaye i-H ibonisa ubukhulu be-microstrip substrate medium.

(4) Akuvumelekanga ukuba iintambo zomqondiso we-RF zinqumle umsantsa wenqwelomoya esemhlabeni womaleko wesibini.
2.3 Iingcingo zomtya
Imiqondiso yerediyo yerediyo ngamanye amaxesha idlula kumbindi we-PCB. Olona luqhelekileyo lusuka kuluhlu lwesithathu. Uluhlu lwesibini kunye nolwesine kufuneka lube ngumhlaba opheleleyo, oko kukuthi, i-eccentric stripline structure. Ubume besakhiwo somgca wokuhluma kuya kuqinisekiswa. Iimfuno ziya kuba:

(1) Imiphetho emacaleni omabini omgca wentambo ubuncinci buyi-3W ububanzi ukusuka kwincam yenqwelomoya ephezulu nasezantsi, kwaye ngaphakathi kwe-3W, akufuneki kubekho ii-vias ezingasekelwanga emhlabeni.

(2) Akuvumelekanga ukuba umgca we-RF unqumle umsantsa phakathi kweenqwelomoya eziphezulu nezisezantsi.

3 Isithuba somngxuma singaphantsi kwe-λ/20, kwaye zicwangciswe ngokulinganayo. Umphetho we-foil yobhedu yomhlaba kufuneka ube bushelelezi, ube flat kwaye akukho burrs ezibukhali.

Kunconywa ukuba umgca wesikhumba sobhedu owenziwe phantsi komhlaba mkhulu okanye ulingana nobubanzi be-1.5W okanye ububanzi be-3H ukusuka kumda we-strip line. I-H imele ubukhulu obupheleleyo bemigangatho ye-dielectric ephezulu nangaphantsi yomgca we-strip.

(4) Ukuba umgca wentambo kukuhambisa imiqondiso yamandla aphezulu, ukuze kuthintelwe ububanzi bomgca wama-50 ohm ukuba bubhityane kakhulu, ngokuqhelekileyo izikhumba zobhedu zeenqwelomoya ezingasentla nezisezantsi zesalathiso zommandla womgca wentambo kufuneka zikhutshelwe ngaphandle, kwaye Ububanzi bomngxuma wokuphuma ngumgca we-strip Ngaphezu kokuphinda-phindwe ka-5 ubukhulu be-dielectric bubonke, ukuba ububanzi bomgca abukafikeleli kwiimfuno, ngoko ke umphezulu kunye nosezantsi omeleneyo wereferensi yenqwelomoya yesibini iyavalwa.