Marka signalka soo noqnoqda ee soo noqnoqda/microwave-ka sare lagu quudiyo PCB wareegga, khasaaraha uu keeno wareegga laftiisa iyo qalabka wareegga ayaa si lama filaan ah u dhalin doona xaddi kuleyl ah. Khasaaraha weyni, ayaa kor u kaca awoodda dhex mareysa walxaha PCB, iyo kuleylka weyn ee soo baxa. Marka heerkulka hawlgalka wareegga uu dhaafo qiimaha la qiimeeyay, wareeggu wuxuu keeni karaa dhibaatooyin. Tusaale ahaan, halbeegga hawlgalka caadiga ah ee MOT, kaas oo aad looga yaqaan PCB-yada, waa heerkulka ugu sarreeya ee hawlgalka. Marka heerkulka hawlgalka uu dhaafo MOT, waxqabadka iyo isku halaynta wareegga PCB waa la hanjabayaa. Isku darka qaabaynta korantada iyo cabbiraadaha tijaabada, fahamka sifooyinka kulaylka ee RF microwave PCBs waxay kaa caawin kartaa in laga fogaado hoos u dhaca waxqabadka wareegga iyo hoos u dhaca kalsoonida ee uu keeno heerkulka sare.

Fahamka sida luminta galinta ay ugu dhacdo agabka wareegga waxay gacan ka geysaneysaa in si wanaagsan loo qeexo arrimaha muhiimka ah ee la xiriira waxqabadka kulaylka ee wareegyada PCB-ga ee soo noqnoqda. Maqaalkani waxa uu qaadan doonaa wareegga xariiqda gudbinta microstrip tusaale ahaan si looga hadlo ganacsiga-offs ee la xidhiidha waxqabadka kulaylka ee wareegga. Wareegga microstrip ee leh qaab-dhismeedka PCB-ga laba-geesoodka ah, khasaaraha waxaa ka mid ah luminta dielectric, luminta kirishbooyada, luminta shucaaca, iyo luminta daadinta. Farqiga u dhexeeya qaybaha kala duwan ee khasaaraha waa weyn. Waxoogaa ka reeban, luminta wareegga-soo noqnoqda ee PCB waa mid aad u hooseeya. Maqaalkan, maadaama qiimaha luminta daadku uu aad u hooseeyo, waa la iska indhatiray doonaa wakhtiga la joogo.

Luminta shucaaca

Radiation loss depends on many circuit parameters such as operating frequency, circuit substrate thickness, PCB dielectric constant (relative dielectric constant or εr) and design plan. As far as design schemes are concerned, radiation loss often stems from poor impedance transformation in the circuit or electromagnetic waves in the circuit. The difference in transmission. Circuit impedance transformation area usually includes signal feed-in area, step impedance point, stub and matching network. Reasonable circuit design can realize smooth impedance transformation, thereby reducing the radiation loss of the circuit. Of course, it should be realized that there is the possibility of impedance mismatch leading to radiation loss at any interface of the circuit. From the point of view of operating frequency, usually the higher the frequency, the greater the radiation loss of the circuit.

Halbeegyada agabka wareegga ee la xidhiidha luminta shucaaca ayaa ah inta badan koronto joogto ah iyo dhumucda alaabta PCB. Marka uu dhumuc weyn yahay substrate-ka wareegga, ayaa sii weyneysa suurtagalnimada in uu keeno luminta shucaaca; hoos udhaca εr ee walxaha PCB, way sii weynaataa luminta shucaaca wareegga. Si guud oo loo miisaamo sifooyinka walxaha, isticmaalka substrates wareegga khafiifka ah waxaa loo isticmaali karaa hab lagu dhimo khasaaraha shucaaca ee ay sababaan qalabka wareegga hoose ee εr. Saamaynta dhumucda substrate-ka wareegga iyo εr ee luminta shucaaca wareegga waa sababtoo ah waa shaqo joogto ah oo ku xiran. Marka dhumucda substrate-ka wareeggu aanu ka badnayn 20mil oo inta jeer ee shaqadu ka hoosayso 20GHz, luminta shucaaca wareeggu aad buu u hooseeyaa. Maaddaama inta badan moodeelka wareegga wareegga iyo cabbiraadaha cabbirka ee maqaalkani ay ka hooseeyaan 20GHz, doodda maqaalkani waxay iska indho tiri doontaa saameynta luminta shucaaca ee kuleylka wareegga.

Ka dib markii la iska indho-tiray luminta shucaaca ka hooseeya 20GHz, galinta luminta wareegga xariiqda gudbinta microstrip waxay inta badan ka kooban tahay laba qaybood: luminta dielectric iyo luminta kirishbooyada. Saamiga labada inta badan waxay ku xiran tahay dhumucda substrate-ka wareegga. Substrate-ka khafiifka ah, luminta kirishbooyada ayaa ah qaybta ugu muhiimsan. Sababo badan dartood, guud ahaan way adagtahay in si sax ah loo saadaaliyo luminta kirishbooyada. Tusaale ahaan, qallafsanaanta dusha sare ee kaareeyaha ayaa saameyn weyn ku leh sifooyinka gudbinta hirarka korantada. Qalafsanaanta dusha sare ee bireed naxaas ah ma beddeli doonto oo keliya faafinta hirarka elektromagnetic ee joogtada ah ee wareegga microstrip, laakiin sidoo kale waxay kordhisaa luminta kaarida wareegga. Saamaynta maqaarka awgeed, saamaynta qallafsanaanta xaashida naxaasta ah ee luminta kireeyaha ayaa sidoo kale ku xidhan inta jeer. Jaantuska 1 wuxuu isbarbar dhigayaa luminta galinta 50 ohm microstrip xadhkaha xariiqda gudbinta ee ku salaysan dhumucda PCB ee kala duwan, kuwaas oo ah 6.6 mils iyo 10 mils, siday u kala horreeyaan.

The simulation results are obtained using Rogers Corporation’s MWI-2010 microwave impedance calculation software. The MWI-2010 software quotes the analytical equations in the classic papers in the field of microstrip line modeling. The test data in Figure 1 is obtained by the differential length measurement method of a vector network analyzer. It can be seen from Fig. 1 that the simulation results of the total loss curve are basically consistent with the measured results. It can be seen from the figure that the conductor loss of the thinner circuit (the curve on the left corresponds to a thickness of 6.6 mil) is the main component of the total insertion loss. As the circuit thickness increases (the thickness corresponding to the curve on the right is 10mil), the dielectric loss and the conductor loss tend to approach, and the two together constitute the total insertion loss.

The circuit material parameters used in the simulation model and the actual circuit are: dielectric constant 3.66, loss factor 0.0037, and copper conductor surface roughness 2.8 um RMS. When the surface roughness of the copper foil under the same circuit material is reduced, the conductor loss of the 6.6 mil and 10 mil circuits in Figure 1 will be significantly reduced; however, the effect is not obvious for the 20 mil circuit. Figure 2 shows the test results of two circuit materials with different roughness, namely Rogers RO4350B™ standard circuit material with high roughness and Rogers RO4350B LoPro™ circuit material with low roughness.

For thinner substrates, the use of smooth copper foil can significantly reduce the insertion loss. For the 6.6mil substrate, the insertion loss is reduced by 0.3 dB due to the use of smooth copper foil at 20GHz; the 10mil substrate is reduced by 0.22 dB at 20GHz; and the 20mil substrate, the insertion loss is only reduced by 0.11 dB.

This means that when the circuit is fed with a certain amount of RF microwave power, the thinner the circuit will generate more heat. When comprehensively weighing the issue of circuit heating, on the one hand, a thinner circuit generates more heat than a thick circuit at high power levels, but on the other hand, a thinner circuit can obtain more effective heat flow through the heat sink. Keep the temperature relatively low.

Si loo xalliyo dhibaatada kuleylka ee wareegga, wareegga khafiifka ah ee ku habboon waa inuu lahaadaa sifooyinka soo socda: factor khasaaro hoose ee walxaha wareegga, naxaas siman oo khafiif ah oo khafiif ah, εr hooseeya iyo kuleylka kuleylka sare. Marka la barbardhigo qalabka wareegga ee εr sare, ballaca kaari ee isku-dhafka la midka ah ee lagu helay xaaladda hoose ee εr wuxuu noqon karaa mid ka weyn, taas oo faa’iido u leh in la yareeyo lumitaanka wareegga wareegga. Marka loo eego aragtida kuleyliyaha wareegga wareegga, inkasta oo inta badan soo noqnoqda PCB substrates ay leeyihiin kulaylka kuleylka aad u liita marka loo eego kirishbooyada, kuleylka kulaylka ee qalabka wareegga ayaa weli ah cabbir aad u muhiim ah.

Doodo badan oo ku saabsan kuleyliyaha kulaylka ee substrates wareegyada ayaa lagu faahfaahiyay maqaaladii hore, maqaalkani wuxuu soo xigan doonaa qaar ka mid ah natiijooyinka iyo macluumaadka maqaaladii hore. Tusaale ahaan, isla’egta soo socota iyo Jaantuska 3 ayaa waxtar leh si loo fahmo arrimaha la xidhiidha waxqabadka kulaylka ee agabka wareegga PCB. Isla’egta, k waa heerkulka kulaylka (W/m/K), A waa aagga, TH waa heerkulka isha kulaylka, TC waa heerkulka isha qabow, iyo L waa masaafada u dhaxaysa isha kulaylka iyo isha qabow.