Nkọwa nke high-frequency PCB board

Ogwe ugboro ugboro dị elu na -ezo aka na bọọdụ sekit elektrọnik pụrụ iche, nke a na -eji ugboro ugboro (karịa 300 MHZ ugboro ma ọ bụ ogologo ebili mmiri erughị 1 mita) na ngwa ndakwa nri (ihe karịrị ugboro 3 GHZ ma ọ bụ ogologo ebili mmiri erughị 0.1 mita) n’ọhịa. PCB, dị na mkpuchi microwave isi ọla kọpa na -eji usoro nrụpụta kọọdụ sekit nkịtị nke akụkụ nke usoro ma ọ bụ iji usoro nhazi pụrụ iche yana imepụta bọọdụ sekit. Na mkpokọta, enwere ike ịkọwa mbadamba ihe dị elu dị ka bọọdụ sekit nwere ugboro ugboro karịa 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. Dịka ọmụmaatụ, ihe mkpụrụ osisi ga -enwerịrị ezigbo ọkụ eletriki, nkwụsi ike kemịkal dị mma, na mmụba nke ugboro mgbaama ike na ihe ndị na -efunahụ mkpụrụ dị ntakịrị, yabụ na -egosipụta mkpa nke efere ugboro ugboro dị elu.

Classification of PCB high frequency plate

1, at the end of the ceramic filled thermosetting material

Usoro nhazi:

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) ihe

Usoro nhazi:

1. Mmeghe ihe: a ga -ejigide fim na -echebe iji gbochie nchapu na ntinye

2. Ihe egwu:

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

2.2 Mpempe akwụkwọ aluminom dị ka efere mkpuchi, wee jiri efere amine buru ibu 1mm, mechie efere PTFE

2.3 Jiri egbe ikuku fụpụsị uzuzu n’ime oghere ahụ

2.4 Site na igwe na -egwu olulu kacha kwụsie ike, ihe ndị na -egwu ala (nke bụ isi, obere oghere, ọnụego ngwangwa ngwa ngwa, ibu Chip pere mpe, ntakịrị nloghachi nloghachi)

3. Nhazi oghere

Ọgwụ Plasma ma ọ bụ sodium – ọgwụgwọ ịgbalite naphthalene bara uru iji mezie pores

4. PTH mikpuo ọla kọpa

4.1 Mgbe micro-etching (20-sentimita XNUMX na-achịkwa ọnụ ọgụgụ micro-etching), a na-eri efere ahụ site na mmanụ na-ewepu cylinder na PTH dọtara.

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:

Kedu ihe mbadamba PCB dị elu? PCB ọkwa ọkwa ugboro ugboro dị elu

Ogologo oge dị elu na ihe mpempe akwụkwọ dị elu

Mgbe ị na -ahọrọ mkpụrụ maka PCB maka okirikiri okirikiri dị elu, ekwesịrị ichebara echiche pụrụ iche maka njirimara mgbanwe nke DK ihe dị iche iche. 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. Karịsịa na ọnụọgụ ugboro site na L MHz ruo L GHz, ụkpụrụ DK na DF ha na -agbanwe nke ọma. 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. N’elu lGHz, ọnụ ahịa DK ya na -agbanwe nwayọ. 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.

Ihe na -akpata ọnwụ dielectric (DF) nke ihe mkpụrụ osisi n’ozuzu karịrị nke DK n’ihi mmetụta nke mgbanwe ugboro ugboro (ọkachasị na oke oke). Yabụ, mgbe anyị na -atụle njirimara ugboro ugboro dị elu nke ihe mgbakwunye, anyị kwesịrị ilekwasị anya na mgbanwe nke uru DF ya. Ihe mkpụrụ osisi nwere oke ọsọ na njiri ugboro ugboro dị elu dị iche na ihe mkpụrụ osisi n’ozuzu ya na njirimara nke mgbanwe na ugboro ugboro. Otu bụ na site na mgbanwe ugboro, ọnụ ahịa ya (DF) na -agbanwe nke ukwuu. Nke ọzọ yiri ihe mkpụrụ osisi n’ozuzu ya na oke mgbanwe, mana uru nke ya (DF) dị ala.

How to choose high frequency high speed plate

Nhọrọ bọọdụ PCB ga -enwerịrị ihe achọrọ, imepụta oke na ọnụ ahịa itule n’etiti. 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.

Kedu ihe mbadamba PCB dị elu? PCB ọkwa ọkwa ugboro ugboro dị elu

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. Iguzosi ike n’ezi ihe nke akara dijitalụ na steepụ nke akụkụ elu na nke ala bụ otu ihe ahụ na mfu dị ala na nnyefe dị ala nke rf microwave (akụkụ harmonic dị elu nke mgbama dijitalụ rutere ngwa ngwa microwave). Therefore, in many respects, the PCB material selection of high-speed digital circuits is similar to the requirements of RF microwave circuits.

Kedu ihe mbadamba PCB dị elu? PCB ọkwa ọkwa ugboro ugboro dị elu

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. Ghọta akụrụngwa eletriki, akụrụngwa ọkụ, ntụkwasị obi, wdg. And rational use of stacking, design a piece of high reliability, good processing products, various factors to consider the best.

Ihe ndị a ga -ewebata isi ihe ndị a ga -atụle na ịhọrọ efere kwesịrị ekwesị:

1, nrụpụta:

Dị ka ọtụtụ ịpị arụmọrụ, arụmọrụ okpomọkụ, nguzogide CAF/ ikpo ọkụ na ike siri ike (viscosity) (ezigbo ntụkwasị obi), ọkwa ọkụ;

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

Ọnwụ dị ala, ntọala Dk/Df kwụsiri ike, mgbasa ozi dị ala, obere mgbanwe mgbanwe na ugboro na gburugburu ebe obibi, obere ndidi nke ọkpụrụkpụ ihe na ọdịnaya roba (njikwa impedance dị mma), ọ bụrụ na waya ahụ dị ogologo, tụlee obere adịghị ike ọla kọpa. In addition, simulation is needed in the early stage of high-speed circuit design, and simulation results are the reference standard for design. Teknụzụ Xingsen-Agilent (nnukwu ọsọ/ugboro ugboro RADIO) ụlọ nyocha njikọta edozila nsogbu arụmọrụ nke nsonaazụ simulation na-ekwekọghị ekwekọ, wee mee ọtụtụ ịme anwansị na nnwale nnwale mechiri emechi, site na ụzọ pụrụ iche iji nweta ịdị n’otu. ịme anwansị na nha.

Kedu ihe mbadamba PCB dị elu? PCB ọkwa ọkwa ugboro ugboro dị elu

3. nnweta ihe n’oge:

Ọtụtụ okirikiri ịzụ ahịa efere ugboro ugboro dị ogologo, ọbụlagodi ọnwa 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. Ihe efu:

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.

Ikwenye na ụkpụrụ gburugburu ebe obibi nke mba dị iche iche wee mezuo ihe achọrọ RoHS na enweghị 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. Efere sekit nwere ọkara na obere mfu ga -adabara sekit dijitalụ 10Gb/S; Efere nwere obere mfu dabara maka elekere dijitalụ 25Gb/s; Ogwe ndị nwere mfu dị ala ga-anabata okirikiri dijitalụ ngwa ngwa, dị elu na ọnụego 50Gb/s ma ọ bụ karịa.

Site na ihe Df:

Df n’etiti 0.01 ~ 0.005 bọọdụ sekit dabara adaba maka oke mgbago dijitalụ 10Gb/S;

Df n’etiti 0.005 ~ 0.003 bọọdụ sekit dabara adaba maka oke mgbago dijitalụ 25Gb/S;

Mbadamba sekit nwere Df na -erughị 0.0015 dabara maka 50Gb/S ma ọ bụ sekit dijitalụ ọsọ dị elu.

Efere ndị a na-eji ọsọ ọsọ ọsọ na-ejikarị bụ:

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

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

3), Panasonic: Megtron4, Megtron6, wdg

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

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

6), Dongguan Shengyi, Taizhou Wangling, Taixing Microwave, wdg