Zida Zosasinthika mu RF Circuits
Resistors, capacitors, tinyanga. . . . Phunzirani za magawo omwe amagwiritsidwa ntchito mumayendedwe a RF.
Makina a RF samasiyana kwenikweni ndi mitundu ina yamagetsi amagetsi. Malamulo omwewo a fiziki amagwiranso ntchito, chifukwa chake zigawo zoyambira zomwe zimagwiritsidwa ntchito pakupanga kwa RF zimapezekanso m'mabwalo a digito ndi ma analogi otsika kwambiri.
Komabe, mapangidwe a RF amaphatikizapo zovuta ndi zolinga zapadera, chifukwa chake mawonekedwe ndi kagwiritsidwe ntchito ka zigawo zake zimafunika kuganiziridwa mwapadera tikamagwira ntchito molingana ndi RF. Komanso, mabwalo ena ophatikizika amachita magwiridwe antchito omwe ali odziwika kwambiri pamakina a RF-sagwiritsidwa ntchito pamabwalo ocheperako ndipo sangamvetsetse bwino ndi omwe sadziwa zambiri ndiukadaulo wamapangidwe a RF.
Nthawi zambiri timagawira zigawo ngati zogwira ntchito kapena zopanda pake, ndipo njira iyi ndi yovomerezeka mu gawo la RF. Nkhaniyi imakambirana zazinthu zomwe zimagwira ntchito makamaka zokhudzana ndi mabwalo a RF, ndipo tsamba lotsatirali limafotokoza zomwe zimagwira ntchito.
Ma capacitors
Capacitor yabwino ingaperekenso magwiridwe antchito ofanana ndi chizindikiro cha 1 Hz ndi chizindikiro cha 1 GHz. Koma zigawozi sizikhala zabwino, ndipo zosagwirizana ndi capacitor zitha kukhala zofunikira kwambiri pama frequency apamwamba.
"C" ikufanana ndi capacitor yabwino yomwe imayikidwa pakati pa zinthu zambiri za parasitic. Tili ndi kukana kopanda malire pakati pa mbale (RD), kukana kwa mndandanda (RS), mndandanda wa inductance (LS), ndi parallel capacitance (CP) pakati pa PCB pads ndi ndege yapansi (tikungotengera zida zapamtunda; zina zambiri pambuyo pake).
Kusavomerezeka kofunikira kwambiri tikamagwira ntchito ndi ma siginecha apamwamba kwambiri ndi inductance. Tikuyembekeza kuti kutsekeka kwa capacitor kucheperachepera nthawi zambiri, koma kupezeka kwa parasitic inductance kumapangitsa kuti kutsekeka kulowe pansi pama frequency a self-resonant kenako ndikuyamba kuwonjezeka:
Resistors, et al.
Ngakhale ma resistors amatha kukhala ovuta pama frequency apamwamba, chifukwa amakhala ndi ma inductance angapo, mphamvu yofananira, komanso mphamvu yofananira ndi PCB pads.
Ndipo izi zimabweretsa mfundo yofunika: mukamagwira ntchito ndi ma frequency apamwamba, ma parasitic circuit akupezeka paliponse. Ziribe kanthu kuti chinthu chotsutsa ndi chophweka bwanji kapena choyenera, chiyenera kupakidwa ndi kugulitsidwa ku PCB, ndipo zotsatira zake ndi parasitics. Zomwezo zimagwiranso ntchito ku chigawo china chilichonse: ngati chapakidwa ndikugulitsidwa ku bolodi, zinthu za parasitic zilipo.
Makhiristo
Chofunikira cha RF ndikuwongolera ma siginecha apamwamba kwambiri kuti apereke zambiri, koma tisanapusitsidwe tiyenera kupanga. Monga mitundu ina ya mabwalo, makhiristo ndi njira yofunikira yopangira ma frequency okhazikika.
Komabe, pamapangidwe a digito ndi osakanikirana, nthawi zambiri zimakhala kuti mabwalo opangidwa ndi kristalo samafunikira kulondola komwe kristalo angapereke, chifukwa chake ndi zophweka kukhala osasamala posankha kristalo. Dongosolo la RF, mosiyana, litha kukhala ndi zofunikira pafupipafupi, ndipo izi sizimafuna kulondola koyambirira komanso kukhazikika pafupipafupi.
Ma frequency oscillation a kristalo wamba amakhudzidwa ndi kusiyanasiyana kwa kutentha. Kusakhazikika kwafupipafupi komwe kumabweretsa kumabweretsa zovuta pamakina a RF, makamaka machitidwe omwe amakumana ndi kutentha kwakukulu kozungulira. Choncho, dongosolo lingafunike TCXO, mwachitsanzo, oscillator wa kristalo wolipiridwa ndi kutentha. Zipangizozi zimaphatikizapo zozungulira zomwe zimalipira kusinthasintha kwa ma crystal:
Tinyanga
Mlongoti ndi chinthu chomwe chimagwiritsidwa ntchito kutembenuza chizindikiro chamagetsi cha RF kukhala ma radiation a electromagnetic radiation (EMR), kapena mosemphanitsa. Ndi zigawo zina ndi ma conductor timayesetsa kuchepetsa zotsatira za EMR, ndipo ndi tinyanga timayesa kukhathamiritsa m'badwo kapena kulandira EMR pokhudzana ndi zosowa za ntchito.
Sayansi ya antenna si yosavuta. Zinthu zosiyanasiyana zimakhudza njira yosankha kapena kupanga tinyanga tomwe titha kugwiritsa ntchito mwanjira inayake. AAC ili ndi zolemba ziwiri (dinani apa ndi apa) zomwe zimapereka chidziwitso chabwino kwambiri chamalingaliro a mlongoti.
Ma frequency apamwamba amatsagana ndi zovuta zamapangidwe osiyanasiyana, ngakhale gawo la tinyanga tadongosolo limatha kukhala locheperako pomwe ma frequency amachulukira, chifukwa ma frequency apamwamba amalola kugwiritsa ntchito tinyanga zazifupi. Masiku ano ndizofala kugwiritsa ntchito "chip antenna," yomwe imagulitsidwa ku PCB ngati zida zapamtunda, kapena mlongoti wa PCB, womwe umapangidwa ndikuphatikiza njira yopangidwira mwapadera pamapangidwe a PCB.
Chidule
Zida zina ndizofala pamapulogalamu a RF, ndipo zina ziyenera kusankhidwa ndikukhazikitsidwa mosamala kwambiri chifukwa cha machitidwe awo okwera kwambiri.
Zomwe zimapangidwira zimawonetsa kuyankha kosasinthika chifukwa cha parasitic inductance ndi capacitance.
Mapulogalamu a RF angafunike makhiristo omwe ali olondola komanso/kapena okhazikika kuposa makhiristo omwe amagwiritsidwa ntchito pamabwalo a digito.
Antennas ndi zinthu zofunika kwambiri zomwe ziyenera kusankhidwa molingana ndi mawonekedwe ndi zofunikira za RF system.
Si Chuan Keenlion Microwave kusankha kwakukulu mumipangidwe yocheperako komanso ma Broadband, kuphimba ma frequency kuchokera ku 0.5 mpaka 50 GHz. Amapangidwa kuti azigwira kuchokera pa 10 mpaka 30 watts kulowetsa mphamvu mu 50-ohm transmission system. Mapangidwe a Microstrip kapena stripline amagwiritsidwa ntchito, ndikukonzedwa kuti azigwira bwino ntchito.
Nthawi yotumiza: Nov-03-2022
