Ufafanuzi wa high-frequency PCB board

Bodi ya masafa ya juu inahusu bodi maalum ya mzunguko wa umeme, inayotumiwa kwa masafa ya juu (zaidi ya 300 MHZ frequency au wavelength ni chini ya mita 1) na microwave (zaidi ya 3 GHZ frequency au wavelength ni chini ya mita 0.1) katika uwanja wa PCB, iko kwenye msingi wa shaba ya microwave iliyotumia njia ya kawaida ya utengenezaji wa bodi ya mzunguko wa sehemu ya mchakato au matumizi ya njia maalum za usindikaji na utengenezaji wa bodi za mzunguko. Kwa ujumla, bodi za masafa ya juu zinaweza kufafanuliwa kama bodi za mzunguko zilizo na masafa juu ya 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. Kwa mfano, vifaa vya mkatetaka vinahitaji kuwa na mali bora za umeme, utulivu mzuri wa kemikali, na kuongezeka kwa masafa ya ishara ya nguvu katika mahitaji ya upotezaji wa substrate ni ndogo sana, kwa hivyo umuhimu wa sahani ya masafa ya juu umeangaziwa.

Classification of PCB high frequency plate

1, at the end of the ceramic filled thermosetting material

Njia ya usindikaji:

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 (polytetrafluoroethilini) nyenzo

Njia ya usindikaji:

1. Ufunguzi wa nyenzo: filamu ya kinga lazima ihifadhiwe ili kuzuia mikwaruzo na ujazo

2. Kuchimba visima:

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

Karatasi ya Aluminium kama bamba, halafu tumia 2.2mm mnene wa amine sahani, kaza sahani ya PTFE

2.3 Puliza vumbi kutoka kwenye shimo na bunduki ya hewa baada ya kuchimba visima

2.4 Na rig imara zaidi ya kuchimba visima, vigezo vya kuchimba visima (kimsingi, ndogo ya shimo, kasi ya kuchimba visima, mzigo mdogo wa Chip, kiwango kidogo cha kurudi)

3. Usindikaji wa shimo

Matibabu ya Plasma au matibabu ya uanzishaji wa sodiamu-naphthalene ni faida kwa metallization ya pores

4. PTH inazama shaba

4.1 Baada ya kuchora-ndogo (kiwango cha kuchoma-ndogo kimedhibitiwa na inchi-20), sahani hulishwa kutoka kwa silinda ya kuondoa mafuta kwenye kuvuta kwa 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:

Je! Ni bodi za mzunguko wa juu za PCB? Uainishaji wa sahani ya frequency ya PCB

Mzunguko wa juu na nyenzo za karatasi ya kasi

Wakati wa kuchagua substrate ya PCB kwa mizunguko ya masafa ya juu, kuzingatia maalum kunapaswa kutolewa kwa sifa tofauti za DK ya nyenzo kwa masafa tofauti. 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. Hasa katika masafa kutoka L MHz hadi L GHz, maadili yao ya DK na DF hubadilika wazi zaidi. 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. Juu ya lGHz, thamani yake ya DK inabadilika kwa upole. 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.

Sababu ya upotezaji wa dielectri (DF) ya nyenzo ya jumla ya mkato ni kubwa kuliko ile ya DK kwa sababu ya ushawishi wa tofauti ya masafa (haswa katika masafa ya juu). Kwa hivyo, wakati wa kukagua sifa za masafa ya juu ya nyenzo ya mkatetaka, tunapaswa kuzingatia mabadiliko ya thamani yake ya DF. Vifaa vya substrate vilivyo na kasi kubwa na sifa za masafa ya juu ni dhahiri tofauti na vifaa vya jumla vya substrate kulingana na sifa za kutofautiana kwa masafa ya juu. Moja ni kwamba na mabadiliko ya masafa, thamani yake (DF) hubadilika kidogo sana. Nyingine ni sawa na nyenzo ya jumla ya substrate katika anuwai ya tofauti, lakini thamani yake (DF) iko chini.

How to choose high frequency high speed plate

Uteuzi wa bodi ya PCB lazima ifikie mahitaji ya muundo, uzalishaji wa wingi na gharama ya usawa kati. 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.

Je! Ni bodi za mzunguko wa juu za PCB? Uainishaji wa sahani ya frequency ya PCB

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. Uadilifu wa ishara ya dijiti na mwinuko wa kingo za juu na chini ni sawa na upotezaji wa chini na usambazaji wa upotoshaji mdogo wa rf microwave (sehemu ya juu ya ishara ya dijiti ya ishara ya dijiti inafikia bendi ya microwave). Therefore, in many respects, the PCB material selection of high-speed digital circuits is similar to the requirements of RF microwave circuits.

Je! Ni bodi za mzunguko wa juu za PCB? Uainishaji wa sahani ya frequency ya PCB

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. Kuelewa mali ya umeme, mali ya mafuta, kuegemea, nk. And rational use of stacking, design a piece of high reliability, good processing products, various factors to consider the best.

Ifuatayo itaanzisha mambo makuu ya kuzingatia katika kuchagua sahani inayofaa:

1, utengenezaji:

Kama utendaji mwingi wa kubonyeza, utendaji wa joto, upinzani wa CAF / joto na ugumu wa mitambo (mnato) (kuegemea vizuri), kiwango cha moto;

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

Kupoteza chini, vigezo vya Dk / Df, utawanyiko mdogo, mgawo mdogo wa mabadiliko na masafa na mazingira, uvumilivu mdogo wa unene wa nyenzo na yaliyomo kwenye mpira (udhibiti mzuri wa impedance), ikiwa waya ni mrefu, fikiria ukali wa chini wa shaba. In addition, simulation is needed in the early stage of high-speed circuit design, and simulation results are the reference standard for design. “Teknolojia ya Xingsen – Agilent (kasi ya juu / masafa ya RADIO) maabara ya pamoja” ilitatua shida ya utendaji wa matokeo na vipimo visivyo sawa vya uigaji, na ilifanya idadi kubwa ya uigaji na uthibitisho halisi wa mtihani uliofungwa, kupitia njia ya kipekee kufanikisha uthabiti wa masimulizi na kipimo.

Je! Ni bodi za mzunguko wa juu za PCB? Uainishaji wa sahani ya frequency ya PCB

3. Upatikanaji wa vifaa kwa wakati unaofaa:

Mzunguko mwingi wa ununuzi wa sahani ya juu ni mrefu sana, hata miezi 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. Sababu za gharama:

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.

Kuendana na kanuni za mazingira za nchi tofauti na kukidhi mahitaji ya RoHS na isiyo 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. Sahani ya mzunguko na upotezaji wa kati na chini itafaa kwa mzunguko wa dijiti wa 10Gb / S; The plate with lower loss is suitable for 25Gb/s digital circuit; Paneli zilizo na upotezaji wa kiwango cha chini zitachukua mizunguko ya dijiti ya kasi, yenye kasi kubwa kwa viwango vya 50Gb / s au zaidi.

From the material Df:

Df kati ya 0.01 ~ 0.005 bodi ya mzunguko inayofaa kwa kikomo cha juu cha 10Gb / S mzunguko wa dijiti;

Df kati ya 0.005 ~ 0.003 bodi ya mzunguko inayofaa kwa kikomo cha juu cha 25Gb / S mzunguko wa dijiti;

Bodi za mzunguko zilizo na Df sio zaidi ya 0.0015 zinafaa kwa 50Gb / S au mizunguko ya dijiti ya kasi zaidi.

Sahani zinazotumiwa kwa kasi sana ni:

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

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

3), Panasonic: Megtron4, Megtron6, nk

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

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

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