Bitewe nubunini nubunini, ntabisanzwe bihari byacapishijwe imiyoboro yumuzunguruko ku isoko rya IoT ryiyongera. Mbere yuko aya mahame asohoka, twagombaga gushingira ku bumenyi n'uburambe mu nganda twize mu iterambere ry'urwego kandi tugatekereza uburyo bwo kubishyira mu bikorwa mu bibazo bidasanzwe bivuka. Hariho ibintu bitatu bisaba ko tubyitaho bidasanzwe. Nibo: ibikoresho byumuzunguruko wububiko, RF / microwave igishushanyo nu murongo wohereza RF.

Ibikoresho bya PCB

"PCB" muri rusange igizwe na laminates, ishobora kuba ikozwe muri epoxy ya fibre-fer (FR4), ibikoresho bya polyimide cyangwa Rogers cyangwa ibindi bikoresho bya laminate. Ibikoresho byo kubika hagati yuburyo butandukanye byitwa prereg.

ibikoresho bishobora kwambara bisaba kwizerwa cyane, mugihe rero abashushanya PCB bahuye noguhitamo gukoresha FR4 (ibikoresho bikoresha PCB bihendutse cyane) cyangwa ibikoresho byateye imbere kandi bihenze, ibi bizaba ikibazo.

Niba porogaramu ya PCB ishobora kwambara isaba umuvuduko mwinshi, ibikoresho byinshi-byihuta, FR4 ntishobora kuba amahitamo meza. Umuyoboro wa dielectric (Dk) wa FR4 ni 4.5, dielectric ihoraho yibikoresho byateye imbere bya Rogers 4003 ni 3.55, naho dielectric ihoraho ya murumuna wa Rogers 4350 ni 3.66.

“Umuyoboro wa dielectric uhoraho wa laminate bivuga ikigereranyo cyubushobozi cyangwa ingufu hagati yimiyoboro ibiri hafi ya laminate na capacitance cyangwa ingufu hagati yabatwara muri vacuum. Kuri frequency nyinshi, nibyiza kugira igihombo gito. Kubwibyo, Roger 4350 hamwe na dielectric ihoraho ya 3.66 irakwiriye cyane kubisabwa inshuro nyinshi kuruta FR4 hamwe na dielectric ihoraho ya 4.5.

Mubihe bisanzwe, umubare wibikoresho bya PCB kubikoresho byambara biri hagati ya 4 na 8. Ihame ryo kubaka ibice ni uko niba ari PCB igizwe na 8, igomba kuba ishobora gutanga ubutaka nimbaraga zihagije hamwe na sandwich wiring. Muri ubu buryo, ingaruka zinyuranyo zambukiranya imipaka zishobora kugumishwa byibuze kandi interineti ya electronique (EMI) irashobora kugabanuka cyane.

Muburyo bwumuzunguruko wibishushanyo mbonera, gahunda yimiterere nugushira mubutaka bunini hafi yububasha bwo gukwirakwiza ingufu. Ibi birashobora gukora ingaruka nkeya cyane, kandi urusaku rwa sisitemu narwo rushobora kugabanuka kugeza kuri zeru. Ibi nibyingenzi byumwihariko kuri radio yumurongo wa sisitemu.

Ugereranije nibikoresho bya Rogers, FR4 ifite ibintu byinshi byo gutandukana (Df), cyane cyane kuri frequency nyinshi. Kubikorwa byisumbuyeho FR4 laminates, agaciro ka Df ni 0.002, ni gahunda yubunini bwiza kuruta FR4 isanzwe. Nyamara, igipande cya Rogers ni 0.001 cyangwa munsi yacyo. Iyo ibikoresho bya FR4 bikoreshwa mugukoresha inshuro nyinshi, hazabaho itandukaniro rikomeye mugutakaza kwinjiza. Igihombo cyo gushiramo gisobanurwa nkigihombo cyikimenyetso cya point kuva A kugeza A B mugihe ukoresheje FR4, Rogers cyangwa ibindi bikoresho.

guteza ibibazo

PCB ishobora kwambara isaba kugenzura gukomeye. Iki nikintu cyingenzi kubikoresho bishobora kwambara. Guhuza impedance birashobora gutanga ibimenyetso bisukuye. Mbere, kwihanganira bisanzwe ibimenyetso bitwara ibimenyetso byari ± 10%. Iki kimenyetso biragaragara ko atari cyiza bihagije kuri uyumunsi-yumurongo mwinshi kandi wihuta. Ibisabwa ubu ni ± 7%, kandi rimwe na rimwe ndetse ± 5% cyangwa munsi yayo. Iyi parameter nizindi mpinduka bizagira ingaruka zikomeye kubikorwa bya PCB zishobora kwambarwa hamwe no kugenzura byimazeyo, bityo bikagabanya umubare wubucuruzi bushobora kubikora.

Dielectric ihora yihanganira laminate ikozwe mubikoresho bya Rogers UHF muri rusange ikomeza kuri ± 2%, ndetse nibicuruzwa bimwe bishobora no kugera kuri ± 1%. Ibinyuranye, dielectric ihora yihanganira laminate ya FR4 iri hejuru ya 10%. Noneho, gereranya Ibi bikoresho byombi urashobora kuboneka ko igihombo cya Rogers kiri hasi cyane. Ugereranije nibikoresho gakondo bya FR4, igihombo cyo kohereza no kwinjiza igihombo cya Rogers kiri munsi y igice.

Mubihe byinshi, ikiguzi nicyo cyingenzi. Ariko, Rogers irashobora gutanga igihombo gito ugereranije-imikorere ya laminate kumikorere ku giciro cyemewe. Kubikorwa byubucuruzi, Rogers irashobora gukorwa muri PCB ivanze hamwe na epoxy ishingiye kuri FR4, ibice bimwe na bimwe bikoresha ibikoresho bya Rogers, nibindi bice bikoresha FR4.

Mugihe uhisemo Rogers stack, inshuro nicyo kintu cyibanze. Iyo inshuro zirenga 500MHz, abashushanya PCB bakunda guhitamo ibikoresho bya Rogers, cyane cyane kumuzunguruko wa RF / microwave, kubera ko ibyo bikoresho bishobora gutanga imikorere ihanitse mugihe ibimenyetso byo hejuru bigenzurwa cyane na impedance.

Ugereranije nibikoresho bya FR4, ibikoresho bya Rogers birashobora kandi gutanga igihombo cya dielectric yo hasi, kandi dielectric ihoraho irahagaze mumurongo mugari. Mubyongeyeho, ibikoresho bya Rogers birashobora gutanga uburyo bwiza bwo kwinjiza igihombo gisabwa nigikorwa kinini.

Coefficient yo kwagura ubushyuhe (CTE) ya Rogers 4000 ibikoresho byuruhererekane bifite ihame ryiza cyane. Ibi bivuze ko ugereranije na FR4, mugihe PCB ihuye nubukonje bukabije, bushyushye kandi bushyushye cyane bwo kugurisha ibicuruzwa, kwaguka kwamashyanyarazi no kugabanya ikibaho cyumuzunguruko birashobora kugumaho kumupaka uhamye mugihe cyinshi nubushyuhe bwinshi.

Kubijyanye no kuvanga ibintu, biroroshye gukoresha tekinoroji yubukorikori isanzwe yo kuvanga Rogers hamwe n’imikorere myinshi ya FR4 hamwe, biroroshye rero kugera ku musaruro mwinshi wo gukora. Ikiraro cya Rogers ntigisaba umwihariko binyuze muburyo bwo kwitegura.

Rusange FR4 ntishobora kugera kumikorere yamashanyarazi yizewe cyane, ariko ibikoresho-byinshi bya FR4 bifite ibintu byiza biranga kwizerwa, nka Tg yo hejuru, iracyari igiciro gito, kandi irashobora gukoreshwa muburyo butandukanye bwa porogaramu, kuva muburyo bworoshye bwamajwi kugeza kuri microwave ikoreshwa. .

Ibitekerezo bya RF / Microwave

Ikoranabuhanga ryimukanwa hamwe na Bluetooth byafunguye inzira ya RF / microwave mubikoresho byambara. Urutonde rwumunsi rwumunsi rugenda rwiyongera. Mu myaka mike ishize, inshuro nyinshi cyane (VHF) yasobanuwe nka 2GHz ~ 3GHz. Ariko ubu turashobora kubona ultra-high frequency (UHF) porogaramu kuva kuri 10GHz kugeza 25GHz.

Kubwibyo, kuri PCB ishobora kwambarwa, igice cya RF gisaba kwita cyane kubibazo byinsinga, kandi ibimenyetso bigomba gutandukana ukundi, kandi ibimenyetso bitanga ibimenyetso byumuvuduko mwinshi bigomba kubikwa kure yubutaka. Ibindi bitekerezo birimo: gutanga akayunguruzo ka bypass, ubushobozi bwa decoupling capacator, guhagarara, no gushushanya umurongo wohereza no kugaruka kumurongo kugirango bingana.

Akayunguruzo ka Bypass karashobora guhagarika ingaruka ziterwa n urusaku hamwe ninzira nyabagendwa. Gukuramo ubushobozi bwa capacitori bigomba gushyirwa hafi yububiko bwibikoresho bitwara ibimenyetso byamashanyarazi.

Imirongo yihuta yihuta hamwe numuyoboro wibimenyetso bisaba urwego rwubutaka rushyirwa hagati yicyapa cyamashanyarazi kugirango cyorohereze jitter iterwa nibimenyetso byurusaku. Ku muvuduko mwinshi wibimenyetso, kudahuza kworoheje bizatera kwanduza no kwakira ibimenyetso, bikaviramo kugoreka. Kubwibyo, hagomba kwitonderwa byumwihariko ikibazo cyo guhuza impedance ijyanye nikimenyetso cya radiyo, kuko ibimenyetso bya radiyo yumurongo bifite umuvuduko mwinshi no kwihanganira bidasanzwe.

Imiyoboro ya RF isaba inzitizi igenzurwa kugirango yohereze ibimenyetso bya RF kuva muri substrate ya IC kuri PCB. Iyi mirongo yohereza irashobora gushyirwa mubikorwa hanze yinyuma, hejuru, no hasi, cyangwa irashobora gushushanywa murwego rwo hagati.

Uburyo bukoreshwa mugihe cya PCB RF igishushanyo mbonera ni umurongo wa microstrip, umurongo ureremba umurongo, coplanar waveguide cyangwa hasi. Umurongo wa microstrip ugizwe n'uburebure butajegajega bw'icyuma cyangwa ibimenyetso hamwe n'indege yose y'ubutaka cyangwa igice cy'indege y'ubutaka munsi yacyo. Ibiranga inzitizi muburyo rusange bwa microstrip kumurongo uri hagati ya 50Ω na 75Ω.

Kureremba kumurongo nubundi buryo bwo gukoresha insinga no guhagarika urusaku. Uyu murongo ugizwe nubugari bwagutse bwagutse kumurongo wimbere hamwe nindege nini yubutaka hejuru no munsi yuyobora hagati. Indege y'ubutaka yashyizwe hagati yindege yingufu, kuburyo ishobora gutanga ingaruka nziza cyane. Ubu ni bwo buryo bwatoranijwe bwo kwambara ibyuma bya PCB RF.

Coplanar waveguide irashobora gutanga ubwigunge bwiza hafi yumuzunguruko wa RF hamwe nizunguruka zigomba kunyuzwa hafi. Ubu buryo bugizwe nuyobora hagati nindege zubutaka kuruhande cyangwa munsi. Inzira nziza yo kohereza ibimenyetso bya radiyo yumurongo ni uguhagarika imirongo cyangwa imirongo ya coplanar. Ubu buryo bubiri burashobora gutanga ubwigunge bwiza hagati yikimenyetso na RF.

Birasabwa gukoresha icyo bita "ukoresheje uruzitiro" kumpande zombi za coplanar waveguide. Ubu buryo burashobora gutanga umurongo wubutaka kuri buri cyuma cyubutaka bwumuyobozi wikigo. Inzira nyamukuru yiruka hagati ifite uruzitiro kuri buri ruhande, bityo igatanga inzira ihita yo kugaruka kumu butaka hepfo. Ubu buryo bushobora kugabanya urusaku rujyanye ningaruka ndende yikimenyetso cya RF. Imiyoboro ya dielectric ya 4.5 ikomeza kuba nkibikoresho bya FR4 bya prereg, mugihe dielectric ihoraho ya prereg - kuva microstrip, stripline cyangwa offset stripline - ni 3.8 kugeza 3.9.

Mubikoresho bimwe na bimwe bikoresha indege yubutaka, vias ihumye irashobora gukoreshwa mugutezimbere imikorere yimikorere ya capacitori no gutanga inzira ya shunt kuva igikoresho kugera kubutaka. Inzira ya shunt igana kubutaka irashobora kugabanya uburebure bwanyuze. Ibi birashobora kugera ku ntego ebyiri: nturema gusa shunt cyangwa igitaka, ahubwo unagabanya intera ihererekanya ryibikoresho bifite uduce duto, nikintu gikomeye cyo gushushanya RF.