Kana iyo yakakwira frequency / microwave radio frequency chiratidzo inopihwa mukati PCB dunhu, kurasikirwa kunokonzerwa nedunhu pacharo uye dunhu zvinhu zvichange zvisingadzivisiki kuburitsa huwandu hwekupisa. Iyo yakakura kurasikirwa, iyo yakakwirira simba rinopfuura nepakati pePCB zvinhu, uye kuwedzera kupisa kunogadzirwa. Kana tembiricha yekushanda yedunhu ichidarika kukosha kwakayerwa, dunhu rinogona kukonzera mamwe matambudziko. Semuenzaniso, iyo yakajairika inoshanda parameter MOT, iyo inozivikanwa kwazvo muPCBs, ndiyo yakanyanya tembiricha yekushandisa. Kana tembiricha yekushanda ichipfuura MOT, kuita uye kuvimbika kwePCB wedunhu kuchatyisidzirwa. Kuburikidza nemusanganiswa we electromagnetic modelling uye kuyedzwa kuyerwa, kunzwisisa hunhu hwekupisa kweRF microwave PCBs kunogona kubatsira kudzivirira kuderedzwa kwekuita kwedunhu uye kuparara kwekuvimbika kunokonzerwa nekupisa kwakanyanya.

Kunzwisisa kuti kurasikirwa kwekuisa kunoitika sei mumidziyo yedunhu kunobatsira kutsanangura zviri nani zvinhu zvakakosha zvine chekuita nekupisa kwekuita kwepamusoro-frequency PCB maseketi. Ichi chinyorwa chichatora microstrip transmission line circuit semuenzaniso wekukurukura nezvekutengeserana kune chokuita nekushanda kwekushisa kwedunhu. Muchikamu chemicrostrip chine mbiri-mativi PCB chimiro, kurasikirwa kunosanganisira kurasikirwa kwedielectric, conductor kurasikirwa, kurasikirwa nemwaranzi, uye kurasikirwa kwekudonha. Musiyano pakati pezvikamu zvekurasikirwa zvakasiyana wakakura. Nezvimwe zvishoma, kurasikirwa kwekudonha kwepamusoro-frequency PCB maseketi kunowanzo kuderera. Muchikamu chino, sezvo kukosha kwekurasikirwa kwekudonha kwakadzikira kwazvo, kucharegeredzwa kwenguva iripo.

Kurasikirwa nemwaranzi

Kurasikirwa nemwaranzi kunoenderana neakawanda ematunhu maparamendi akadai sekushanda frequency, redunhu substrate ukobvu, PCB dielectric kugara (relative dielectric constant kana εr) uye dhizaini chirongwa. Nekuda kwezvirongwa zvekugadzira, kurasikirwa nemwaranzi kunowanzo kunobva mukusarudzika kwakashata kweiyo impedance mudunhu kana mutsauko wemagetsi emagetsi wave kutapurirana mudunhu. Circuit impedance shanduko nzvimbo inowanzo sanganisira chiratidzo chekudya-munzvimbo, nhanho impedance poindi, stub uye inofananidza network. Inonzwisisika yedunhu dhizaini inogona kuona yakatsetseka impedance shanduko, nekudaro ichidzikisa kurasikirwa nemwaranzi yedunhu. Ehe, zvinofanirwa kucherechedzwa kuti pane mukana we impedance mismatch inotungamira mukurasikirwa neradiation pane chero interface yedunhu. Kubva pakuona kwekushanda frequency, kazhinji iyo yakakwirira iyo frequency, yakakura kurasikirwa nemwaranzi yedunhu.

Iwo maparamendi emidziyo yedunhu ane chekuita nekurasikirwa nemwaranzi anonyanya dielectric anogara uye PCB zvinhu ukobvu. Iyo yakakura yedunhu substrate, iyo yakakura mukana wekukonzera kurasikirwa nemwaranzi; iyo yakaderera iyo εr yePCB zvinhu, iyo yakakura kurasikirwa nemwaranzi yedunhu. Kunyatsoyera huremu hwezvinhu, kushandiswa kwematete edunhu substrates kunogona kushandiswa senzira yekumisa kurasikirwa nemwaranzi kunokonzerwa neakaderera εr wedunhu zvinhu. Iko kurudziro yedunhu substrate ukobvu uye εr pakurasikirwa kwemwaranzi yedunhu imhaka yekuti ibasa rinoenderana nefrequency. Kana ukobvu hwedunhu substrate husingapfuure 20mil uye frequency yekushanda yakaderera pane 20GHz, kurasikirwa nemwaranzi kwedunhu kwakadzikira. Sezvo mazhinji edunhu rekuenzanisa uye kuyerwa mafambiro muchinyorwa ichi akadzikira kupfuura 20GHz, nhaurirano iri muchinyorwa ichi haichafuratira kukanganiswa kwekurasikirwa nemwaranzi pakudziya kwedunhu.

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

Migumisiro yakayerwa uye yakatevedzwa

Iyo curve muFigure 1 ine zvakayerwa mhedzisiro uye simulation mhedzisiro. Mhedzisiro yekuenzanisa inowanikwa nekushandisa Rogers Corporation’s MWI-2010 microwave impedance calculation software. Iyo MWI-2010 software inotora equation yekuongorora mumapepa echinyakare mumunda weiyo microstrip line modelling. Iyo data yekuyedza muMufananidzo 1 inowanikwa nenzira yekusiyanisa urefu hwekuyera nzira yevector network analyzer. Inogona kuonekwa kubva kuMufananidzo 1 kuti migumisiro yekufananidza yehuwandu hwekurasikirwa kwepamusoro inonyanya kuenderana nemigumisiro yakayerwa. Zvinogona kuonekwa kubva pamufananidzo kuti kondakita kurasikirwa kwedunhu rakatetepa (iyo curve kuruboshwe inoenderana nehupamhi hwe 6.6 mil) ndiyo chikamu chikuru chekurasikirwa kwese kwekuisa. Sezvo ukobvu hwedunhu hunowedzera (ukobvu hunoenderana necurve kurudyi i10mil), kurasikirwa kwedielectric uye kurasikirwa kwekondukita kunosvika, uye zviviri pamwe chete zvinoumba kurasikirwa kwese kwekuisa.

Iyo yekufananidza modhi muMufananidzo 1 uye maparamita emagetsi edunhu anoshandiswa mudunhu chairo ndeaya: dielectric inogara 3.66, kurasikirwa chinhu 0.0037, uye mhangura conductor pamusoro roughness 2.8 um RMS. Kana hutsinye hwepamusoro hwemhangura yemhangura pasi pechigadziro chimwechete chedunhu chakaderedzwa, kurasikirwa kwekondukita kwe6.6 mil uye 10 mil circuits muMufananidzo 1 kuchaderedzwa zvakanyanya; zvisinei, mhedzisiro yacho haisi pachena kune 20 mil redunhu. Mufananidzo 2 unoratidza mhedzisiro yebvunzo yezvinhu zviviri zvedunhu zvine hukasha hwakasiyana, zvinoti Rogers RO4350B ™ yakajairwa redunhu zvinhu zvine hutsinye hwakanyanya uye Rogers RO4350B LoPro ™ wedunhu zvinhu zvine yakaderera roughness.

Sezvinoratidzwa muMufananidzo 1 uye Mufananidzo 2, iyo yakaonda yedunhu substrate, iyo yakakwirira yekuisa kurasikirwa kwedunhu. Izvi zvinoreva kuti kana dunhu rapihwa imwe huwandu hweRF microwave simba, iyo yakatetepa dunhu inoburitsa kupisa kwakawanda. Paunenge uchiyera zvakanyanya nyaya yekudziya kwedunhu, kune rumwe rutivi, dunhu rakatetepa rinoburitsa kupisa kwakawanda kupfuura dunhu gobvu pamazinga emagetsi akakwira, asi kune rimwe divi, dunhu rakatetepa rinogona kuwana kuyerera kwekushisa kunoshanda kuburikidza nekunyura kwekupisa. Chengeta tembiricha yakaderera.

Kuti ugadzirise dambudziko rekupisa redunhu, iyo yakanakira yakaonda dunhu inofanirwa kuve neanotevera maitiro: yakaderera kurasikirwa chinhu chedunhu zvinhu, yakatsetseka mhangura yakaonda nzvimbo, yakaderera εr uye yakakwirira yekupisa conductivity. Kuenzaniswa nedunhu repamusoro εr, iyo conductor hupamhi hweiyo impedance yakafanana inowanikwa pasi pemamiriro epasi εr inogona kuva yakakura, iyo inobatsira kuderedza conductor kurasikirwa kwedunhu. Kubva pakuona kwekupisa kupisa kwedunhu, kunyangwe mazhinji epamusoro-frequency PCB wedunhu substrates ane urombo hwekupisa conductivity hukama nemakondakita, iyo yekupisa conductivity yedunhu zvinhu ichiri yakakosha parameter.

Nhaurirano dzakawanda pamusoro pekupisa kwekupisa kwematunhu substrates kwakatsanangurwa muzvinyorwa zvekare, uye chinyorwa ichi chichataura mamwe mhedzisiro uye ruzivo kubva muzvinyorwa zvekare. Semuenzaniso, equation inotevera uye Figure 3 inobatsira kunzwisisa zvinhu zvine chekuita nekupisa kwekuita kwePCB yedunhu zvinhu. Muequation, k ndiyo thermal conductivity (W/m/K), A ndiyo nzvimbo, TH tembiricha yenzvimbo inopisa, TC ndiyo tembiricha yenzvimbo inotonhora, uye L ndiyo chinhambwe pakati pekupisa uye kwaitonhora.