Saboda ƙaramin girman da girman, kusan babu ƙa'idodin hukumar da'ira da aka buga don haɓakar kasuwar IoT mai lalacewa. Kafin waɗannan ƙa'idodin su fito, dole ne mu dogara da ilimin da ƙwarewar masana'antu da aka koya a cikin haɓaka matakin hukumar kuma muyi tunanin yadda za mu yi amfani da su ga ƙalubale masu tasowa na musamman. Akwai fannoni guda uku da suke bukatar kulawa ta musamman. Su ne: kayan saman allo, ƙirar RF/Microwave da layin watsa RF.

PCB abu

“PCB” gabaɗaya ya ƙunshi laminates, waɗanda ƙila za a yi su da fiber-reinforced epoxy (FR4), polyimide ko Rogers kayan ko wasu kayan laminate. Abun rufewa tsakanin nau'ikan yadudduka daban-daban ana kiransa prepreg.

na'urorin da za a iya sawa suna buƙatar babban dogaro, don haka lokacin da masu zanen PCB suka fuskanci zaɓi na amfani da FR4 (kayan masana'anta na PCB mafi tsada) ko ƙarin ci gaba da kayan tsada, wannan zai zama matsala.

Idan aikace-aikacen PCB masu sawa suna buƙatar babban sauri, kayan mitoci masu girma, FR4 bazai zama mafi kyawun zaɓi ba. Dielectric akai-akai (Dk) na FR4 shine 4.5, dielectric akai-akai na mafi ci-gaba Rogers 4003 jerin kayan shine 3.55, kuma dielectric akai-akai na jerin 'yan'uwa Rogers 4350 shine 3.66.

“Matsalar dielectric na laminate yana nufin rabon capacitance ko makamashi tsakanin wasu masu gudanarwa a kusa da laminate zuwa capacitance ko makamashi tsakanin biyu na conductors a cikin injin. A babban mitoci, yana da kyau a sami ƙaramin asara. Saboda haka, Roger 4350 tare da dielectric akai-akai na 3.66 ya fi dacewa da aikace-aikacen mitar mafi girma fiye da FR4 tare da madaidaicin dielectric na 4.5.

A ƙarƙashin yanayi na al'ada, adadin yadudduka na PCB don na'urori masu sawa suna jeri daga yadudduka 4 zuwa 8. Ka'idar gina Layer ita ce idan PCB mai Layer 8 ne, yakamata ya iya samar da isasshen ƙasa da yadudduka mai ƙarfi da sandwich ɗin wiring Layer. Ta wannan hanyar, za'a iya kiyaye tasirin raɗaɗi a cikin taɗi zuwa ƙarami kuma ana iya rage tsangwama na lantarki (EMI).

A cikin tsarin ƙirar ƙirar allon kewayawa, tsarin shimfidawa gabaɗaya shine sanya babban Layer ƙasa kusa da layin rarraba wutar lantarki. Wannan na iya haifar da tasiri mai ƙarancin ƙarfi, kuma ana iya rage ƙarar tsarin zuwa kusan sifili. Wannan yana da mahimmanci musamman ga tsarin mitar rediyo.

Idan aka kwatanta da kayan Rogers, FR4 yana da mafi girman ɓarna factor (Df), musamman a babban mitar. Don mafi girman aiki FR4 laminates, ƙimar Df kusan 0.002 ne, wanda shine tsari na girma fiye da FR4 na yau da kullun. Koyaya, tarin Rogers shine kawai 0.001 ko ƙasa da haka. Lokacin da aka yi amfani da kayan FR4 don aikace-aikacen mitoci masu girma, za a sami babban bambanci a cikin asarar sakawa. An ayyana asarar shigarwa azaman asarar wutar sigina daga aya A zuwa aya B yayin amfani da FR4, Rogers ko wasu kayan.

haifar da matsaloli

PCB mai sawa yana buƙatar kulawa mai ƙarfi. Wannan muhimmin abu ne ga na'urori masu sawa. Daidaitawar impedance na iya samar da watsa sigina mai tsabta. Tun da farko, daidaitaccen haƙuri don siginar ɗaukar alamun shine ± 10%. Wannan alamar a fili ba ta da kyau ga maɗaukakin mitoci da na'urori masu sauri na yau. Abin da ake buƙata na yanzu shine ± 7%, kuma a wasu lokuta ma ± 5% ko ƙasa da haka. Wannan siga da sauran masu canji za su yi tasiri sosai ga kera waɗannan PCBs masu sawa tare da tsauraran matakan kariya, ta yadda za su iyakance adadin kasuwancin da za su iya kera su.

Haƙurin dielectric akai-akai na laminate da aka yi da kayan Rogers UHF ana kiyaye shi gabaɗaya a ± 2%, kuma wasu samfuran na iya kaiwa ± 1%. Sabanin haka, haƙurin dielectric akai-akai na laminate FR4 ya kai 10%. Saboda haka, kwatanta waɗannan abubuwa guda biyu za a iya gano cewa asarar shigar Rogers ta yi ƙasa sosai. Idan aka kwatanta da kayan FR4 na gargajiya, asarar watsawa da asarar shigar da tarin Rogers ya ragu da ƙasa.

A mafi yawan lokuta, farashi shine mafi mahimmanci. Duk da haka, Rogers na iya samar da ƙarancin ƙarancin hasarar babban aikin laminate a wani madaidaicin farashi. Don aikace-aikacen kasuwanci, za a iya sanya Rogers zuwa PCB masu haɗaka tare da FR4 na tushen epoxy, wasu yadudduka waɗanda ke amfani da kayan Rogers, wasu yadudduka kuma suna amfani da FR4.

Lokacin zabar tarin Rogers, mita shine babban abin la'akari. Lokacin da mitar ta wuce 500MHz, masu zanen PCB sukan zaɓi kayan Rogers, musamman don da'irori na RF/Microwave, saboda waɗannan kayan na iya samar da mafi girman aiki lokacin da manyan burbushi ke da ƙarfi ta hanyar impedance.

Idan aka kwatanta da kayan FR4, kayan Rogers kuma na iya samar da ƙananan asarar dielectric, kuma dielectric akai-akai yana da ƙarfi a cikin kewayon mitar mita. Bugu da kari, Rogers abu na iya samar da manufa low saka asarar yi da ake bukata ta high mita aiki.

Matsakaicin haɓakar haɓakar thermal (CTE) na kayan jerin abubuwan Rogers 4000 yana da kwanciyar hankali mai girma. Wannan yana nufin cewa idan aka kwatanta da FR4, lokacin da PCB ke fama da yanayin sanyi, zafi da zafi sosai, za'a iya kiyaye faɗaɗawar zafi da ƙanƙancewar allon kewayawa a ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun zazzaɓi.

A cikin hali na gauraye stacking, yana da sauki a yi amfani da na kowa masana'antu tsari fasaha don Mix Rogers da high-yi FR4 tare, don haka yana da in mun gwada da sauki cimma high masana'antu yawan amfanin ƙasa. Tarin Rogers baya buƙatar na musamman ta hanyar tsari.

FR4 gama gari ba zai iya samun ingantaccen aikin lantarki abin dogaro ba, amma kayan aikin FR4 masu inganci suna da kyawawan halaye masu inganci, kamar Tg mafi girma, har yanzu ƙarancin farashi, kuma ana iya amfani da su a cikin aikace-aikacen da yawa, daga ƙirar sauti mai sauƙi zuwa aikace-aikacen microwave Complex .

Abubuwan ƙira na RF/Microwave

Fasaha mai ɗaukuwa da Bluetooth sun share hanya don aikace-aikacen RF/Microwave a cikin na'urori masu sawa. Mitar ta yau tana ƙara ƙarfi. Bayan 'yan shekarun da suka gabata, an bayyana mitar mita sosai (VHF) azaman 2GHz ~ 3GHz. Amma yanzu muna iya ganin aikace-aikacen mitar ultra-high (UHF) daga 10GHz zuwa 25GHz.

Don haka, don PCB mai sawa, ɓangaren RF yana buƙatar ƙarin kulawa ga al'amuran wayoyi, kuma yakamata a ware sigina daban, kuma alamun da ke haifar da sigina mai girma yakamata a kiyaye su daga ƙasa. Sauran abubuwan la'akari sun haɗa da: samar da tacewa ta hanyar kewayawa, isassun masu sarrafa kayan aiki, ƙaddamar da ƙasa, da tsara layin watsawa da dawo da layin kusan daidai.

Tace ta ƙetare na iya murkushe tasirin abin da ke cikin amo da ƙetaren magana. Ana buƙatar a sanya masu haɗa capacitors kusa da fil ɗin na'urar ɗauke da siginar wuta.

Layukan watsawa masu sauri da da'irori na sigina suna buƙatar sanya shimfiɗar ƙasa tsakanin siginonin madaurin wuta don santsin jitter ɗin da siginar amo ke haifarwa. A mafi girman saurin sigina, ƙananan rashin daidaituwa na impedance zai haifar da watsa rashin daidaituwa da karɓar sigina, yana haifar da murdiya. Don haka, dole ne a ba da kulawa ta musamman ga matsalar daidaitawa da ke da alaƙa da siginar mitar rediyo, saboda siginar mitar rediyo tana da saurin gudu da haƙuri na musamman.

Layukan watsa RF suna buƙatar rashin ƙarfi mai sarrafawa don watsa siginar RF daga takamaiman IC substrate zuwa PCB. Ana iya aiwatar da waɗannan layukan watsawa a saman Layer na waje, saman saman, da saman ƙasa, ko kuma ana iya tsara su a tsakiyar Layer.

Hanyoyin da aka yi amfani da su yayin shimfidar ƙirar PCB RF sune layin microstrip, layin tsiri mai iyo, jagorar igiyar ruwa ko ƙasa. Layin microstrip ya ƙunshi ƙayyadadden tsayi na ƙarfe ko alamu da dukan jirgin ƙasa ko wani ɓangare na jirgin ƙasa kai tsaye a ƙarƙashinsa. Halayen impedance a cikin tsarin layin microstrip gabaɗaya ya bambanta daga 50Ω zuwa 75Ω.

Tsari mai iyo wata hanya ce ta wayoyi da kuma hana surutu. Wannan layin ya ƙunshi ƙayyadaddun wayoyi masu faɗi a kan rufin ciki da kuma babban jirgin ƙasa sama da ƙasa da mai gudanarwa na tsakiya. Jirgin ƙasa yana yin sandwiched tsakanin jirgin wutar lantarki, don haka zai iya samar da tasiri mai tasiri sosai. Wannan ita ce hanyar da aka fi so don wayar siginar PCB RF mai sawa.

Coplanar waveguide na iya samar da mafi kyawun keɓewa kusa da da'irar RF da da'irar da ake buƙatar tuntuɓar ta kusa. Wannan matsakaici ya ƙunshi madugu na tsakiya da jiragen ƙasa a kowane gefe ko ƙasa. Hanya mafi kyau don watsa siginar mitar rediyo ita ce ta dakatar da layin tsiri ko jagororin raƙuman ruwa. Waɗannan hanyoyi guda biyu na iya samar da mafi kyawun keɓewa tsakanin siginar da alamun RF.

Ana ba da shawarar yin amfani da abin da ake kira "ta hanyar shinge" a ɓangarorin biyu na jagoran waveguide na coplanar. Wannan hanya na iya samar da jeri na ƙasa ta hanyar kowane jirgin ƙasa na ƙarfe na cibiyar gudanarwa. Babban alamar da ke gudana a tsakiyar yana da shinge a kowane gefe, don haka yana ba da gajeren hanya don dawowar halin yanzu zuwa ƙasa a ƙasa. Wannan hanya na iya rage matakin amo mai alaƙa da babban tasirin siginar RF. Dielectric akai-akai na 4.5 ya kasance daidai da kayan FR4 na prepreg, yayin da dielectric akai-akai na prepreg-daga microstrip, stripline ko soket ɗin tsiri-yana kusan 3.8 zuwa 3.9.

A wasu na'urorin da ke amfani da jirgin sama na ƙasa, ana iya amfani da makafi ta hanyar sadarwa don inganta aikin gyaran wutar lantarki da samar da hanyar shunt daga na'urar zuwa ƙasa. Hanyar shunt zuwa ƙasa na iya rage tsawon ta hanyar. Wannan na iya cimma dalilai guda biyu: ba kawai ku ƙirƙiri shunt ko ƙasa ba, amma har ma kuna rage nisan watsawa na na'urori tare da ƙananan yankuna, wanda shine muhimmin ƙirar ƙirar RF.