Tlhaloso ea high-frequency PCB board

Boto e phahameng ea maqhubu e bua ka boto e khethehileng ea potoloho ea motlakase ea motlakase, e sebelisoang khafetsa (e fetang 300 MHZ frequency kapa wavelength e ka tlase ho mithara e le ‘ngoe) le microwave (e fetang 1 GHZ frequency kapa wavelength e ka tlase ho limithara tsa 3) lebaleng la PCB, e holim’a microwave base koporo e apereng e sebelisa mokhoa o tloaelehileng o thata oa ho etsa boto ea potoloho ea karolo ea ts’ebetso kapa ts’ebeliso ea mekhoa e ikhethileng ea ts’ebetso le tlhahiso ea liboto tsa potoloho. Ka kakaretso, liboto tsa maqhubu a phahameng li ka hlalosoa e le liboto tsa potoloho tse nang le maqhubu a kaholimo ho 1GHz.

With the rapid development of science and technology, more and more equipment design is in the microwave band (> 1GHZ) and even with the millimeter wave field (30GHZ) above the application, which also means that the frequency is higher and higher, the substrate of the circuit board requirements are also higher and higher. Mohlala, thepa ea substrate e hloka ho ba le thepa e ntle ea motlakase, botsitso bo botle ba lik’hemik’hale, ka keketseho ea maqhubu a matla a matla ho litlhoko tsa tahlehelo ea substrate li nyane haholo, ka hona ho totobatsoa bohlokoa ba poleiti e phahameng.

Classification of PCB high frequency plate

1, at the end of the ceramic filled thermosetting material

Mokhoa o sebetsang:

And epoxy resin/glass woven cloth (FR4) similar processing process, but the plate is more brittle, easy to break, drilling and gong plate drill nozzle and gong knife life is reduced by 20%.

2. PTFE (polytetrafluoroethylene) lintho tse bonahalang

Mokhoa o sebetsang:

1. Ho buloa ha lintho tse bonahalang: Filimi e sireletsang e tlameha ho bolokoa ho thibela mengoapo le phomolo

2. The tirila:

2.1 use a new drill (standard 130), one piece stacked is the best, the presser foot pressure is 40psi

2.2 Aluminium lakane e le poleiti ea sekoahelo, ebe u sebelisa poleiti ea 1mm e teteaneng ea amine, tiisa sethala sa PTFE

2.3 Ts’ula lerole ka sekoting ka sethunya sa moea kamora ho cheka

2.4 Ka mochini o tsitsitseng ka ho fetisisa oa ho cheka, mekhahlelo ea ho cheka (ha e le hantle, sekoti se nyane, lebelo la ho cheka le potlakile, mojaro o monyane oa Chip, o monyane sekhahla sa ho khutla)

3. Ts’ebetso ea lesoba

Kalafo ea plasma kapa kalafo ea ts’ebetso ea sodium-naphthalene e molemo ho metallization ea pores

4. PTH e teba koporo

4.1 Kamora ho cheka manonyeletso (sekhahla sa ho cheka ka bongata bo nyane se laoloe ke li-intshi tse 20), poleiti e fepeloa ho tsoa ka silindara e tlosang oli ho PTH

4.2 If necessary, go through the second PTH, just from the forecast? The cylinder began to enter the plate

5. The resistance welding

5.1 Pre-treatment: use acid washing plate instead of mechanical grinding plate

5.2 After pre-treatment, bake plate (90℃, 30min), brush green oil and cure

5.3 Three baking plates: one is 80℃, 100℃ and 150℃ for 30min each (if oil is found on the substrate surface, it can be reworked: wash off the green oil and reactivate it)

6. Gong board

Lay the white paper on the PTFE board circuit surface, and clamp it with fr-4 base plate or phenolic base plate with a thickness of 1.0mm and copper removal: As shown in the figure:

Ke PCB mapolanka phahameng maqhubu a eng? PCB phahameng maqhubu poleiti tlhophiso

Maqhubu a phahameng le thepa ea lakane e lebelo haholo

Ha u khetha substrate bakeng sa PCB bakeng sa lipotoloho tse maqhubu a phahameng, ho lokela ho fanoe ka tlhokomelo e khethehileng ho litšobotsi tse fapaneng tsa DK ea lintho tse bonahalang maemong a fapaneng. For the requirements of signal high-speed transmission or characteristic impedance control, DF and its performance under the conditions of frequency, temperature and humidity are mainly investigated.

Under the condition of frequency variation, the DK and DF values of general substrate materials change greatly. Haholo-holo ho maqhubu a tsoang ho L MHz ho ea ho L GHz, litekanyetso tsa bona tsa DK le DF li fetoha ka ho hlaka. For example, the GENERAL epoxy – glass fiber substrate material (general FR-4) has a DK value of 4.7 at lMHz and a DK value of 4.19 at lGHz. Ka holim’a lGHz, boleng ba eona ba DK bo fetoha ka bonolo. For example, under l0GHz, the DK value of FR-4 is 4.15. For substrate materials with high speed and high frequency characteristics, the DK value changes slightly. From lMHz to lGHz, the DK value mostly stays within 0.02 range. The DK value tends to decrease slightly at different frequencies from low to high.

Sesebelisoa sa tahlehelo ea dielectric (DF) ea thepa e akaretsang ea substrate e kholo ho feta ea DK ka lebaka la tšusumetso ea phapano ea maqhubu (haholoholo maemong a phahameng a maqhubu). Ka hona, ha re lekola litšobotsi tse phahameng tsa maqhubu a thepa ea substrate, re lokela ho shebana le phetoho ea boleng ba eona ba DF. Lisebelisoa tsa substrate tse nang le lebelo le lebelo le phahameng haholo li hlakile ho fapana le thepa ea substrate ka kakaretso ho latela litšobotsi tse fapaneng tsa maqhubu a phahameng. E ‘ngoe ke hore ka phetoho ea maqhubu, boleng ba eona (DF) bo fetoha hanyane haholo. E ‘ngoe e ts’oana le thepa e akaretsang ea substrate ka bongata ba mefuta, empa boleng ba eona (DF) bo tlase.

How to choose high frequency high speed plate

Khetho ea boto ea PCB e tlameha ho fihlela litlhokahalo tsa moralo, tlhahiso ea bongata le litšenyehelo tsa tekano lipakeng. In short, the design requirements consist of two components: electrical and structural reliability. This is usually important when designing very high speed PCB boards (frequencies greater than GHz). For example, the fr-4 material commonly used today may not be applicable due to its large Df (Dielectricloss) at several GHz frequencies.

Ke PCB mapolanka phahameng maqhubu a eng? PCB phahameng maqhubu poleiti tlhophiso

For example, a 10Gb/S high-speed digital signal is a square wave, which can be regarded as a superposition of sinusoidal signals of different frequencies. Therefore, 10Gb/S contains many different frequency signals: 5Ghz fundamental signal, 3 order 15GHz, 5 order 25GHz, 7 order 35GHz signal, etc. Botšepehi ba lets’oao la dijithale le botebo ba likhahla tse kaholimo le tse tlase li ts’oana le phokotso e tlase le phetisetso e tlase ea khopiso ea rf microwave (karolo e phahameng ea maqhubu a harmonic ea lets’oao la dijithale e fihla sehlopheng sa microwave). Therefore, in many respects, the PCB material selection of high-speed digital circuits is similar to the requirements of RF microwave circuits.

Ke PCB mapolanka phahameng maqhubu a eng? PCB phahameng maqhubu poleiti tlhophiso

In practical engineering operations, the selection of high-frequency plates seems simple, but there are still many factors to be considered. Through the introduction of this paper, AS a PCB design engineer or a high-speed project leader, I have a certain understanding of the characteristics and selection of plates. Utloisisa thepa ea motlakase, thepa ea mocheso, ts’epahalo, jj. And rational use of stacking, design a piece of high reliability, good processing products, various factors to consider the best.

Tse latelang li tla hlahisa lintlha tsa mantlha tse lokelang ho tsotelloa ha ho khethoa poleiti e loketseng:

1, tlhahiso:

Joalo ka ts’ebetso e ngata e hatellang, ts’ebetso ea mocheso, CAF / ho hanyetsa mocheso le ho thatafala ha mochini (viscosity) (ts’epahalo e ntle), tekanyo ea mollo;

2, with the product matching performance (electrical, performance stability, etc.) :

Tahlehelo e tlase, mekhahlelo e tsitsitseng ea Dk / Df, ho hasana ho fokolang, phetoho e nyane ea sekhahla le maqhubu le tikoloho, mamello e nyane ea botenya ba lintho tse bonahalang le rabara (taolo e ntle ea impedance), haeba terata e le telele, nahana ka botenya ba koporo e tlase. In addition, simulation is needed in the early stage of high-speed circuit design, and simulation results are the reference standard for design. “Xingsen Technology – Agilent (lebelo le phahameng / maqhubu a RADIO) laboratori e kopaneng” e rarolotse bothata ba ts’ebetso ea sephetho le liteko tse sa lumellaneng, mme e entse palo e kholo ea ketsiso le netefatso ea liteko tse koetsoeng, ka mokhoa o ikhethileng oa ho fihlela ts’ebetsong ea ketsiso le tekanyo.

Ke PCB mapolanka phahameng maqhubu a eng? PCB phahameng maqhubu poleiti tlhophiso

3. Ho fumaneha ha thepa ka nako e loketseng:

Potoloho e ngata ea theko ea maqhubu a maqhubu a malelele e telele haholo, esita le likhoeli tse 2-3; In addition to the conventional high frequency plate RO4350 has inventory, many high frequency plates need to be provided by customers. Therefore, high frequency plate and manufacturers need to communicate well in advance, as soon as possible;

4. Lintho tse theko:

Depending on the price sensitivity of the product, whether it is a consumer product, or a telecommunications, medical, industrial, military application;

5. Applicability of laws and regulations, etc.

Ho tsamaellana le melaoana ea tikoloho ea linaha tse fapaneng le ho fihlela litlhoko tsa RoHS ebile ha e na halogen.

Among the above factors, the running speed of high-speed digital circuit is the main factor to consider in PCB selection. The higher the circuit speed, the smaller the selected PCBDf value should be. Poleiti ea potoloho e nang le tahlehelo e mahareng le e tlase e tla tšoanela potoloho ea dijithale ea 10Gb / S; The plate with lower loss is suitable for 25Gb/s digital circuit; Liphanele tse nang le tahlehelo e tlase haholo li tla amohela lipotoloho tsa dijithale tse potlakileng, tse lebelo le phahameng ka litefiso tsa 50Gb / s kapa ho feta.

Ho tsoa boitsebisong Df:

Df lipakeng tsa 0.01 ~ 0.005 boto ea potoloho e loketseng moeli o kaholimo oa potoloho ea dijithale ea 10Gb / S;

Df lipakeng tsa 0.005 ~ 0.003 boto ea potoloho e loketseng moeli o kaholimo oa potoloho ea dijithale ea 25Gb / S;

Liboto tsa potoloho tse nang le Df tse sa feteng 0.0015 li loketse 50Gb / S kapa li-circuits tsa dijithale tse phahameng.

Lipoleiti tse sebelisoang ka tloaelo ke tsena:

1), Rogers: RO4003, RO3003, RO4350, RO5880, jj

2), Taiyao TUC: Tuc862, 872SLK, 883, 933, jj

3), Panasonic: Megtron4, Megtron6, jj

4), Isola: FR408HR, IS620, IS680, jj

5) Nelco: N4000-13, N4000-13EPSI, jj

6), Dongguan Shengyi, Taizhou Wangling, Taixing Microwave, joalo-joalo