Thaum lub siab zaus/microwave xov tooj cua zaus teeb liab yog pub rau hauv PCB Circuit Court, qhov poob tshwm sim los ntawm Circuit Court nws tus kheej thiab cov khoom siv hauv Circuit Court yuav inevitably tsim ib qho nqi ntawm cov cua sov. Qhov poob ntau dua, lub zog ntau dua dhau los ntawm cov khoom siv PCB, thiab qhov ntau dua cov cua sov tsim. Thaum qhov ntsuas kub ntawm lub voj voog ua haujlwm tshaj qhov ntsuas tus nqi, lub voj voog yuav ua rau qee qhov teeb meem. Piv txwv li, qhov kev khiav hauj lwm tsis zoo MOT, uas paub zoo hauv PCBs, yog qhov siab tshaj plaws kev khiav hauj lwm kub. Thaum qhov kub ntawm kev khiav hauj lwm tshaj qhov MOT, qhov kev ua tau zoo thiab kev ntseeg siab ntawm PCB Circuit Court yuav raug hem. Los ntawm kev sib xyaw ua ke ntawm cov qauv siv hluav taws xob thiab kev sim ntsuas, kev nkag siab txog cov yam ntxwv thermal ntawm RF microwave PCBs tuaj yeem pab kom tsis txhob muaj kev cuam tshuam ntawm Circuit Court degradation thiab kev ntseeg siab degradation los ntawm qhov kub thiab txias.

Kev nkag siab yuav ua li cas qhov kev puas tsuaj tshwm sim hauv cov khoom siv hauv Circuit Court yuav pab tau zoo dua piav qhia txog qhov tseem ceeb ntsig txog kev ua haujlwm thermal ntawm high-frequency PCB circuits. Kab lus no yuav coj cov microstrip kis kab hluav taws xob los ua piv txwv los tham txog kev lag luam tawm cuam tshuam txog kev ua haujlwm thermal ntawm Circuit Court. Nyob rau hauv ib lub microstrip Circuit Court nrog ob-sided PCB qauv, kev poob muaj xws li dielectric poob, conductor poob, hluav taws xob poob, thiab leakage poob. Qhov sib txawv ntawm qhov sib txawv ntawm cov khoom poob yog qhov loj. Nrog qee qhov kev zam, qhov xau poob ntawm high-frequency PCB circuits feem ntau qis heev. Nyob rau hauv tsab xov xwm no, txij li thaum tus nqi poob qis heev, nws yuav tsis quav ntsej rau lub sijhawm.

Cov hluav taws xob poob

Kev tawg hluav taws xob nyob ntawm ntau yam tsis sib xws xws li kev khiav hauj lwm zaus, Circuit Court substrate thickness, PCB dielectric tas li (tus txheeb ze dielectric tas li los yog εr) thiab kev npaj tsim. Raws li cov qauv tsim muaj kev txhawj xeeb, hluav taws xob poob feem ntau tshwm sim los ntawm kev hloov pauv tsis zoo hauv lub voj voog lossis qhov sib txawv ntawm cov hluav taws xob hluav taws xob sib kis hauv Circuit Court. Circuit impedance transformation cheeb tsam feem ntau suav nrog cov teeb liab pub-hauv cheeb tsam, kauj ruam impedance point, stub thiab txuam network. Tsim nyog Circuit Court tsim tuaj yeem paub qhov kev hloov pauv ntawm impedance, yog li txo qhov hluav taws xob poob ntawm Circuit Court. Ntawm chav kawm, nws yuav tsum tau paub hais tias muaj peev xwm ntawm impedance mismatch ua rau hluav taws xob poob ntawm ib qho kev sib tshuam ntawm Circuit Court. Los ntawm qhov pom ntawm kev khiav hauj lwm zaus, feem ntau yog qhov siab dua, qhov ntau dua qhov hluav taws xob poob ntawm lub voj voog.

Cov khoom tsis sib xws ntawm cov khoom siv hluav taws xob ntsig txog hluav taws xob poob yog feem ntau dielectric tas li thiab cov khoom siv PCB thickness. Lub thicker lub Circuit Court substrate, qhov ntau dua qhov ua rau hluav taws xob poob; qhov qis dua εr ntawm cov khoom siv PCB, qhov ntau dua qhov hluav taws xob poob ntawm lub voj voog. Comprehensively hnyav cov yam ntxwv, kev siv ntawm nyias Circuit Court substrates yuav siv tau raws li ib txoj kev los offset lub hluav taws xob poob los ntawm tsawg εr Circuit Court cov ntaub ntawv. Kev cuam tshuam ntawm Circuit Court substrate thickness thiab εr ntawm hluav taws xob hluav taws xob poob yog vim nws yog ib qho kev ua haujlwm ntau zaus. Thaum lub thickness ntawm Circuit Court substrate tsis tshaj 20mil thiab kev khiav hauj lwm zaus yog qis dua 20GHz, qhov hluav taws xob poob ntawm lub Circuit Court yog tsawg heev. Txij li feem ntau ntawm cov qauv hauv Circuit Court thiab ntsuas zaus hauv kab lus no yog qis dua 20GHz, kev sib tham hauv kab lus no yuav tsis quav ntsej txog kev cuam tshuam ntawm hluav taws xob poob ntawm hluav taws xob hluav taws xob.

After ignoring the radiation loss below 20GHz, the insertion loss of a microstrip transmission line circuit mainly includes two parts: dielectric loss and conductor loss. The proportion of the two mainly depends on the thickness of the circuit substrate. For thinner substrates, conductor loss is the main component. For many reasons, it is generally difficult to accurately predict conductor loss. For example, the surface roughness of a conductor has a huge influence on the transmission characteristics of electromagnetic waves. The surface roughness of copper foil will not only change the electromagnetic wave propagation constant of the microstrip circuit, but also increase the conductor loss of the circuit. Due to the skin effect, the influence of copper foil roughness on conductor loss is also frequency-dependent. Figure 1 compares the insertion loss of 50 ohm microstrip transmission line circuits based on different PCB thicknesses, which are 6.6 mils and 10 mils, respectively

Ntsuas thiab simulated tau

Qhov nkhaus hauv daim duab 1 muaj cov ntsuas ntsuas thiab cov txiaj ntsig simulation. Cov txiaj ntsig simulation tau txais los ntawm kev siv Rogers Corporation’s MWI-2010 microwave impedance xam software. MWI-2010 software quotes cov kev sib npaug sib npaug hauv cov ntawv classic hauv kev ua qauv ntawm microstrip kab. Cov ntaub ntawv xeem hauv daim duab 1 yog tau los ntawm kev ntsuas qhov ntev sib txawv ntawm tus vector network analyzer. Nws tuaj yeem pom los ntawm daim duab 1 tias cov txiaj ntsig simulation ntawm tag nrho cov kev poob nkhaus yog qhov yooj yim raws li qhov ntsuas tau. Nws tuaj yeem pom los ntawm daim duab uas tus neeg xyuas pib poob ntawm lub thinner Circuit Court (qhov nkhaus ntawm sab laug sib raug rau lub thickness ntawm 6.6 mil) yog qhov tseem ceeb ntawm tag nrho cov kev nkag mus. Raws li lub Circuit Court thickness nce (lub thickness sib haum mus rau lub nkhaus ntawm sab xis yog 10mil), lub dielectric poob thiab tus neeg xyuas pib poob yuav mus kom ze, thiab ob qho tib si ua rau tag nrho cov insertion poob.

Cov qauv simulation hauv daim duab 1 thiab cov khoom siv hluav taws xob tsis siv nyob rau hauv qhov tseeb Circuit Court yog: dielectric qhov tsis tu ncua 3.66, qhov poob qis 0.0037, thiab tooj liab conductor nto roughness 2.8 um RMS. Thaum qhov roughness ntawm cov ntawv ci tooj liab nyob rau hauv tib cov khoom siv hluav taws xob raug txo qis, tus neeg xyuas pib poob ntawm 6.6 mil thiab 10 mil circuits hauv daim duab 1 yuav txo qis; Txawm li cas los xij, cov nyhuv tsis pom tseeb rau 20 mil circuit. Daim duab 2 qhia txog cov txiaj ntsig ntawm ob qhov khoom siv hluav taws xob uas muaj qhov sib txawv, uas yog Rogers RO4350B ™ cov khoom siv hluav taws xob uas muaj qhov siab roughness thiab Rogers RO4350B LoPro ™ cov khoom siv hluav taws xob uas tsis tshua muaj roughness.

Raws li pom nyob rau hauv daim duab 1 thiab daim duab 2, lub thinner lub Circuit Court substrate, qhov siab dua qhov nkag poob ntawm Circuit Court. Qhov no txhais tau hais tias thaum lub Circuit Court yog pub nrog ib tug npaum li cas ntawm RF microwave lub hwj chim, lub thinner lub Circuit Court yuav ua kom muaj cua sov ntau. Thaum ua tib zoo ntsuas qhov teeb meem ntawm cov hluav taws xob hluav taws xob, ntawm ib sab, ib qho hluav taws xob nyias nyias tsim hluav taws xob ntau dua li cov hluav taws xob tuab ntawm cov hluav taws xob siab, tab sis ntawm qhov tod tes, ib lub voj voog nyias nyias tuaj yeem tau txais cov cua sov zoo dua los ntawm lub dab dej kub. Khaws qhov kub thiab txias.

Yuav kom daws tau qhov teeb meem cua sov ntawm lub voj voog, qhov zoo tshaj plaws nyias Circuit Court yuav tsum muaj cov yam ntxwv hauv qab no: qhov poob qis ntawm cov khoom siv hauv Circuit Court, du tooj liab nyias nto, qis εr thiab siab thermal conductivity. Piv nrog rau cov khoom siv hauv Circuit Court ntawm siab εr, tus neeg xyuas pib dav ntawm tib lub impedance tau txais nyob rau hauv cov xwm txheej ntawm qis εr tuaj yeem loj dua, uas yog qhov zoo los txo cov neeg xyuas pib poob ntawm Circuit Court. Los ntawm kev xav ntawm Circuit Court kub dissipation, txawm hais tias feem ntau high-frequency PCB Circuit Court substrates muaj cov thermal conductivity tsis zoo rau cov conductors, thermal conductivity ntawm cov khoom siv hluav taws xob tseem yog qhov tseem ceeb heev.

Muaj ntau qhov kev sib tham txog cov thermal conductivity ntawm cov hluav taws xob hluav taws xob hauv hluav taws xob tau piav qhia hauv cov khoom ua ntej, thiab tsab xov xwm no yuav hais txog qee qhov txiaj ntsig thiab cov ntaub ntawv los ntawm cov ntawv dhau los. Piv txwv li, cov kab zauv hauv qab no thiab daim duab 3 yuav pab tau kom nkag siab txog cov yam tseem ceeb uas cuam tshuam txog kev ua haujlwm thermal ntawm PCB cov khoom siv hluav taws xob. Hauv qhov sib npaug, k yog qhov thermal conductivity (W / m / K), A yog thaj tsam, TH yog qhov kub ntawm qhov chaw tshav kub, TC yog qhov kub ntawm qhov txias, thiab L yog qhov kev ncua deb ntawm qhov kub thiab txias. qhov chaw txias.