The interconnect of bosilgan elektron karta tizim chip-to-elektron karta, tenglikni ichida o’zaro ulanish va tenglikni va tashqi qurilmalar o’rtasida ulanishni o’z ichiga oladi. In RF design, the electromagnetic characteristics at the interconnect point is one of the main problems faced by engineering design. This paper introduces various techniques of the above three types of interconnect design, including device installation methods, isolation of wiring and measures to reduce lead inductance.

Bosilgan elektron platalarning chastotasi oshib borayotgani haqida belgilar bor. As data rates continue to increase, the bandwidth required for data transmission also pushes the signal frequency ceiling to 1GHz or higher. This high frequency signal technology, although far beyond the millimeter wave technology (30GHz), does involve RF and low-end microwave technology.

RF muhandislik dizayn usullari odatda yuqori chastotalarda hosil bo’ladigan kuchli elektromagnit maydon effektlarini boshqarishi kerak. Bu elektromagnit maydonlar qo’shni signal chizig’ida yoki tenglikni chizig’ida signallarni keltirib chiqarishi mumkin, bu esa istalmagan to’qnashuvni (shovqin va umumiy shovqin) va tizimning ishlashiga zarar etkazishi mumkin. Backloss is mainly caused by impedance mismatch, which has the same effect on the signal as additive noise and interference.

High return loss has two negative effects: 1. The signal reflected back to the signal source will increase the noise of the system, making it more difficult for the receiver to distinguish noise from signal; 2. 2. Har qanday aks ettirilgan signal signal sifatini yomonlashtiradi, chunki kirish signalining shakli o’zgaradi.

Raqamli tizimlar faqat 1 va 0 signallari bilan ishlaganligi sababli xatolarga chidamli bo’lsa -da, puls yuqori tezlikda ko’tarilganda hosil bo’ladigan harmonikalar signalni yuqori chastotalarda kuchsizroq bo’lishiga olib keladi. Oldinga xatolarni tuzatish ba’zi salbiy ta’sirlarni bartaraf etishi mumkin bo’lsa -da, tizimning tarmoqli kengligining bir qismi ortiqcha ma’lumotlarni uzatish uchun ishlatiladi, natijada ishlash yomonlashadi. A better solution is to have RF effects that help rather than detract from signal integrity. It is recommended that the total return loss at the highest frequency of a digital system (usually a poor data point) be -25dB, equivalent to a VSWR of 1.1.

PCB design aims to be smaller, faster and less costly. For RFPCB, high-speed signals sometimes limit the miniaturization of PCB designs. At present, the main method to solve the crosseration problem is to carry out ground connection management, conduct spacing between wiring and reduce lead inductance. Qaytish yo’qotilishini kamaytirishning asosiy usuli – impedans mosligi. Bu usul izolyatsiyalash materiallarini samarali boshqarishni va faol signal liniyalari va tuproqli chiziqlarni, ayniqsa signal chizig’i va erning holatini ajratishni o’z ichiga oladi.

O’zaro bog’lanish zanjir zanjirining eng zaif bo’g’ini bo’lgani uchun, RF dizaynida, o’zaro bog’lanish nuqtasining elektromagnit xususiyatlari muhandislik dizayni oldida turgan asosiy muammo hisoblanadi, har bir ulanish nuqtasini tekshirish va mavjud muammolarni hal qilish kerak. O’chirish platasining o’zaro bog’liqligi chiplar va elektron kartalar o’zaro bog’liqligini, tenglikni o’zaro bog’liqligini va PCB va tashqi qurilmalar orasidagi signal kirish/chiqish ulanishini o’z ichiga oladi.

I. Chip va tenglikni kartasi o’rtasidagi o’zaro bog’liqlik

Bu yechim ishlaydimi yoki yo’qmi, ishtirokchilarga IC dizayn texnologiyasi hf ilovalari uchun tenglikni dizayn texnologiyasidan ancha oldinda ekanligi ayon bo’ldi.

PCB o’zaro bog’liqligi

HF PCB dizaynining texnikasi va usullari quyidagicha:

1. Qaytish yo’qotilishini kamaytirish uchun uzatish liniyasi burchagi uchun 45 ° burchakdan foydalanish kerak (1 -rasm);

Qat’iy nazorat qilinadigan yuqori samarali izolyatsion elektron karta darajasiga ko’ra 2 izolyatsiyali doimiy qiymat. This method is beneficial for effective management of electromagnetic field between insulating material and adjacent wiring.

3. PCB design specifications for high precision etching should be improved. +/- 0.0007 dyuymli umumiy chiziq kengligi xatosini, simi shakllarining kesilgan va kesimlarini boshqarishni va devorning yon devorlari bilan qoplash shartlarini belgilashni o’ylab ko’ring. Overall management of wiring (wire) geometry and coating surfaces is important to address skin effects related to microwave frequencies and to implement these specifications.

4. Chiqib ketgan uchlarda kran indüktansi bor. Qo’rg’oshinli komponentlarni ishlatishdan saqlaning. Yuqori chastotali muhit uchun sirtga o’rnatilgan komponentlardan foydalanish yaxshidir.

5. Teshiklar orqali signal berish uchun sezgir plastinkada PTH jarayonini ishlatishdan saqlaning, chunki bu jarayon teshik orqali qo’rg’oshin indüktansiga olib kelishi mumkin. Lead inductance can affect layers 4 to 19 if a through-hole in a 20-ply board is used to connect layers 1 to 3.

6. Provide abundant ground layers. Moulded holes are used to connect these grounding layers to prevent 3d electromagnetic fields from affecting the circuit board.

7. Elektrolizsiz nikel qoplama yoki suvga botiruvchi oltin qoplamali jarayonni tanlash uchun HASL qoplama usulini ishlatmang. This electroplated surface provides a better skin effect for high-frequency currents (Figure 2). In addition, this highly weldable coating requires fewer leads, helping to reduce environmental pollution.

8. Solder resistance layer can prevent solder paste from flowing. Biroq, qalinlikning noaniqligi va izolyatsiyaning noma’lumligi tufayli plastinkaning butun yuzasini lehimga chidamli material bilan qoplash mikrostriplar dizaynida elektromagnit energiyaning katta o’zgarishiga olib keladi. Generally, solderdam is used as welding resistance layer.

Agar siz bu usullarni bilmasangiz, harbiylar uchun mikroto’lqinli elektron platalarda ishlagan tajribali dizayner -muhandisga murojaat qiling. You can also discuss with them what price range you can afford. Misol uchun, mis chiziqli Coplanar mikrostripli konstruktsiyani chiziqli dizayndan foydalanish ancha tejamli va siz yaxshiroq maslahat olish uchun buni ular bilan muhokama qilishingiz mumkin. Yaxshi muhandislar xarajatlar haqida o’ylashga odatlanmagan bo’lishi mumkin, lekin ularning maslahatlari juda foydali bo’lishi mumkin. RF effektlari bilan tanish bo’lmagan va RF effektlari bilan ishlash tajribasiga ega bo’lmagan yosh muhandislarni o’qitish uzoq muddatli ish bo’ladi.

Bunga qo’shimcha ravishda, boshqa echimlarni ham qabul qilish mumkin, masalan, RF ta’sirini boshqarish uchun kompyuter modelini takomillashtirish.

PCB tashqi qurilmalar bilan o’zaro bog’liqligi

Endi biz taxtada va diskret komponentlarning o’zaro bog’lanishida signallarni boshqarish bilan bog’liq barcha muammolarni hal qildik deb taxmin qilishimiz mumkin. Xo’sh, elektron kartadan masofali qurilmani bog’laydigan simga signalni kiritish/chiqarish muammosini qanday hal qilasiz? Koaksiyal kabel texnologiyasining innovatori TrompeterElectronics bu muammo ustida ishlamoqda va ba’zi muhim yutuqlarga erishdi (3 -rasm). Also, take a look at the electromagnetic field shown in Figure 4 below. Bunday holda, biz mikrostripdan koaksiyal kabelga o’tishni boshqaramiz. Koaksiyal kabellarda, er qatlamlari halqalarga o’ralgan va teng ravishda joylashtirilgan. Mikro belbog’larda topraklama qatlami faol chiziq ostidadir. Bu dizayn vaqtida tushunilishi, bashorat qilinishi va ko’rib chiqilishi kerak bo’lgan ba’zi bir yon ta’sirlarni keltirib chiqaradi. Albatta, bu nomuvofiqlik ham orqaga qaytishga olib kelishi mumkin va shovqin va signal shovqiniga yo’l qo’ymaslik uchun minimallashtirilishi kerak.

Ichki impedans muammosini boshqarish dizayn muammosi emas, uni e’tiborsiz qoldirib bo’lmaydi. The impedance starts at the surface of the circuit board, passes through a solder joint to the joint, and ends at the coaxial cable. Empedans chastotaga qarab o’zgarganligi sababli, chastota qanchalik baland bo’lsa, empedansni boshqarish shunchalik qiyin bo’ladi. The problem of using higher frequencies to transmit signals over broadband appears to be the main design problem.