Ngaphezu kokuthikamezeka komugqa wesiginali ye-RF, uhlaka olunalayini lwebhodi elilodwa le-RF PCB nalo ludinga ukucabangela izindaba ezinjengokunqanyulwa kokushisa, okwamanje, amadivaysi, i-EMC, ukwakheka nomphumela wesikhumba. Imvamisa sisekwendlaleni nasekunqwabelenisweni kwamabhodi aphrintiwe anezingqimba eziningi. Landela izimiso eziyisisekelo:
A) Ungqimba ngalunye lwe-RF PCB lumbozwe indawo enkulu ngaphandle kwendiza yamandla. Izendlalelo eziseduze ezingaphezulu neziphansi zongqimba lwezintambo ze-RF kufanele kube izindiza eziphansi.
Ngisho noma kuyibhodi elixubile le-analog yedijithali, ingxenye yedijithali ingaba nendiza yamandla, kodwa indawo ye-RF kusafanele ihlangabezane nemfuneko yokugandaywa kwendawo enkulu esitezi ngasinye.
B) Kuphaneli ephindwe kabili ye-RF, ungqimba olungaphezulu luyisiginali, futhi ungqimba olungezansi luyindiza ephansi.
Ibhodi elilodwa le-RF elinezingqimba ezine, ungqimba olungaphezulu ungqimba lwesignali, ungqimba lwesibili nolwesine amaplanethi aphansi, kanti ungqimba lwesithathu olwamandla nokulawula imigqa. Ezimweni ezikhethekile, eminye imigqa yesiginali ye-RF ingasetshenziswa kungqimba lwesithathu. Izendlalelo ezengeziwe zamabhodi e-RF, njalonjalo.
C) Ku-backplane ye-RF, izingqimba ezingaphezulu nezingaphansi zombili ziphansi. Ukuze kuncishiswe ukungaqhubeki kwe-impedance okubangelwa ama-vias nezixhumi, izendlalelo zesibili, zesithathu, zesine, nezesihlanu zisebenzisa amasignali edijithali.
Ezinye izendlalelo ze-stripline endaweni engezansi zonke ziyizimpawu ezingezansi. Ngokufanayo, izingqimba ezimbili eziseduze zongqimba lwesignali ye-RF kufanele zibe phansi, futhi ungqimba ngalunye kufanele lumbozwe indawo enkulu.
D) Kumabhodi e-RF anamandla amakhulu, amanje aphezulu, isixhumanisi esikhulu se-RF kufanele sibekwe phezu kwesendlalelo esiphezulu futhi sixhunywe ngomugqa obanzi we-microstrip.
Lokhu kusiza ekulahlekeni kokushisa nokulahlekelwa amandla, kunciphisa amaphutha okugqwala kwezintambo.
E) Indiza yamandla yengxenye yedijithali kufanele ibe seduze nendiza yaphansi futhi ihlelwe ngaphansi kwendiza ephansi.
Ngale ndlela, amandla phakathi kwamapuleti amabili ensimbi angasetshenziswa njenge-capacitor eshelelayo yokunikezwa kwamandla, futhi ngesikhathi esifanayo, indiza ephansi futhi ingavikela amandla emisebe asakazwa endizeni yamandla.
Indlela ethile yokunqwabelanisa kanye nezidingo zokuhlukaniswa kwendiza zingabhekisa kokuthi “Izimfuneko Zokwakhiwa Kwebhodi Lesifunda Ephrintiwe Ka-20050818-EMC” ezimenyezelwe uMnyango Wokuklama we-EDA, futhi amazinga aku-inthanethi azosebenza.
2
Izidingo zezintambo zebhodi le-RF
2.1 Ikhona
Uma ukulandelelwa kwesignali ye-RF kuhamba ngama-engeli angakwesokudla, ububanzi bomugqa obusebenzayo emakhoneni buzokhuphuka, futhi i-impedance izoyeka futhi ibangele ukubonakaliswa. Ngakho-ke, kuyadingeka ukubhekana namakhona, ikakhulukazi ngezindlela ezimbili: ukusika ekhoneni nokuzungeza.
(1) Ikhona elisikiwe lilungele ukugoba okuncane, futhi imvamisa esebenzayo yekhona elisikiwe ingafinyelela ku-10GHz.
(2) Irediyasi ye-engeli ye-arc kufanele ibe nkulu ngokwanele. Ngokuvamile, qinisekisa: R>3W.
2.2 Izintambo zeMicrostrip
Ungqimba olungaphezulu lwe-PCB luphethe isignali ye-RF, futhi ungqimba lwendiza ngaphansi kwesignali ye-RF kufanele kube indiza ephansi egcwele ukuze yakhe umugqa we-microstrip isakhiwo. Ukuqinisekisa ubuqotho besakhiwo somugqa we-microstrip, kunezidingo ezilandelayo:
(1) Amaphethelo ezinhlangothini zombili zomugqa we-microstrip kufanele okungenani abe ububanzi obungu-3W ukusuka onqenqemeni lwendiza yaphansi ngezansi. Futhi ebangeni le-3W, akumele kube nama-via angasekelwe phansi.
(2) Ibanga phakathi komugqa we-microstrip nodonga oluyisivikelo kufanele ligcinwe ngaphezu kuka-2W. (Qaphela: W ububanzi bomugqa).
(3) Imigqa ye-microstrip engahlanganisiwe kungqimba olufanayo kufanele iphathwe ngesikhumba sethusi esiphansi futhi i-vias yomhlabathi kufanele yengezwe esikhumbeni sethusi esiphansi. Isikhala sembobo singaphansi kuka-λ/20, futhi ahlelwe ngokulinganayo.
Umkhawulo we-foil yethusi yomhlabathi kufanele ube bushelelezi, uyisicaba, futhi ungabi nama-burrs abukhali. Kutuswa ukuthi unqenqema lwethusi elivalwe phansi likhulu noma lilingane nobubanzi obungu-1.5W noma u-3H kusukela emaphethelweni omugqa we-microstrip, futhi u-H umele ukujiya kwe-microstrip substrate medium.
(4) Akuvunyelwe ukuthi izintambo zesignali ye-RF ziwele igebe lendiza yaphansi yongqimba lwesibili.
2.3 Izintambo ezinezintambo
Amasignali efrikhwensi yomsakazo kwesinye isikhathi adlula engxenyeni ephakathi ye-PCB. Okuvame kakhulu kuvela kungqimba lwesithathu. Izendlalelo zesibili nezesine kufanele zibe indiza yomhlabathi ephelele, okungukuthi, isakhiwo se-stripline eccentric. Ubuqotho besakhiwo bomugqa wokuqhafaza buzoqinisekiswa. Izidingo zizoba:
(1) Amaphethelo ezinhlangothini zombili zomugqa wokucushwa okungenani anobubanzi obungu-3W ukusuka emaphethelweni endiza yaphansi nangaphezulu, futhi ngaphakathi kuka-3W, akumele kube khona ama-vias angagxiliwe.
(2) Akuvunyelwe ukuthi i-stripline ye-RF yeqe igebe phakathi kwezindiza eziphansi neziphezulu.
(3) Imigqa ye-strip kungqimba olufanayo kufanele iphathwe ngesikhumba sethusi esiphansi futhi i-vias yomhlabathi kufanele yengezwe esikhumbeni sethusi esiphansi. Isikhala sembobo singaphansi kuka-λ/20, futhi ahlelwe ngokulinganayo. Umkhawulo we-foil yethusi yomhlabathi kufanele ube bushelelezi, uyisicaba futhi ungabi nama-burrs abukhali.
Kunconywa ukuthi unqenqema lwesikhumba sethusi esigqoke phansi bukhulu noma bulingana nobubanzi obungu-1.5W noma ububanzi obungu-3H kusukela emaphethelweni omugqa wokuhluthula. U-H umele ubukhulu obuphelele bezendlalelo ze-dielectric ezingaphezulu neziphansi zomugqa we-strip.
(4) Uma umugqa wentambo kuwukudlulisa amasignali anamandla amakhulu, ukuze ugweme ububanzi bomugqa wama-ohm angu-50 ukuba bube buncane kakhulu, ngokuvamile izikhumba zethusi zezindiza eziyisethenjwa ezingenhla nezingaphansi zendawo yomugqa kufanele zikhishwe, futhi ububanzi bomgodi umugqa we-strip Iphindwe izikhathi ezingaphezu kwezi-5 ubukhulu bengqikithi ye-dielectric, uma ububanzi bomugqa namanje bungahlangabezani nezidingo, khona-ke izindiza zereferensi zesendlalelo sesibili ezingenhla neziphansi eziseduze ziyakhishwa.