Новости PCB - подробное описание материалов и классификаций

высокочастотная пластина - специальная плата с высокой электромагнитной частотой, which is used for high frequency (frequency greater than 300MHZ or wavelength less than 1 meter) and microwave (frequency greater than 3GHZ or wavelength less than 0.1 meter)

The PCB in the category is a circuit board produced by operating the departmental process of the popular rigid circuit board manufacturing method on the microwave substrate copper clad board or adopting a special treatment method. Вообще говоря, high-frequency boards can be defined as circuit boards with frequencies above 1GHz.

1. Classification of PCB high frequency plates.

Ceramic filling thermosetting material
Processing methods:
The processing flow is similar to epoxy resin/glass woven cloth (FR4), except that the sheet is brittle and easily breaks. когда сверление и гонг, ресурс жиклеров и гонгов уменьшен на 20%.

2. PTFE (polytetrafluoroethylene) material
Processing method:

(1). Cutting material: It is necessary to save the shelter film cutting material to avoid scratches and indentations

(2). Drilling:

2.1 Use a brand new drill (size 130), один за другим будет лучшим, the pressure of the presser foot is 40psi

2.2 The aluminum sheet is the cover plate, and then the 1mm melamine backing plate is used to hold the PTFE plate tightly

2.после бурения, use an air gun to blow out the dust in the hole

2.4 Use the most constant drilling rig and drilling parameters (basically, Чем меньше дыра, the faster the drilling speed, Чем меньше нагрузка на кристалл, the lower the return speed)

3. Via treatment
Plasma treatment or sodium naphthalene activation treatment is conducive to hole metallization

4. PTH Immersion Copper

4.1 After micro-etching (with a micro-etching rate of 20 microinches controlled), start the board from the de-oil tank in the PTH pull

4.В случае необходимости, pass the second PTH, just start with the estimated cylinder and enter the board

5. Solder mask

5.1 Pre-treatment: Take acidic washing of the plates, and do not use machines to grind the plates

5.2 Pre-treatment and post-baking plate (90„ƒ, 30min), brush with green oil to cure

5.3 трехсегментная сушка: температура сушки 80°C, 100°C, 150 градусов по цельсию, each for 30 minutes (if the substrate surface is oiled, it can be reworked: wash off the green oil and reactivate it)

6. Gong board

Lay the white paper on the circuit surface of the PTFE board, и скрепление бакелитовой плиткой FR - 4 или бакелитовой плиткой толщиной 1.0MM etched to remove copper:

As shown in the picture: High frequency and high speed board material

When selecting the substrate used in the PCB for high-frequency circuits, необходимо специально проверить материал DK и его характеристики преобразования на различных частотах.

требования для высокоскоростной передачи сигналов, or characteristic impedance control requirements, ориентация и ее характеристики, температура и влажность.

Under the premise of frequency change, обычный базовый материал показывает большую закономерность изменения значений DK и DF.

Especially in the frequency range from 1 MHz to 1 GHz, их значения DK и DF существенно изменились.

According to the coating online, the DK value of ordinary epoxy resin-glass fiber cloth-based substrate material (ordinary FR-4) at a frequency of 1MHz is 4.

7. величина DK на частоте 1GHz изменена на 4.19. Over 1GHz, изменение значений DK.

The trend of its transformation is to follow the increase in frequency, and then become smaller (but the transformation amplitude is not large), например, under l0GHz, обычный FR - 4 значение DK 4.15, and the substrate material with high-speed and high-frequency characteristics changes in frequency. в обстановке, the change of DK value is relatively small. при переходе от 1мHz к 1GHz, DK is mostly connected to a 0.преобразование масштаба 02.

Its DK value tends to drop slightly under the premise of varying frequency from low to high.

The dielectric loss factor (DF) of the ordinary substrate material is affected by the frequency change (except for the change in the high-frequency scale) and the change in the DF value is greater than the DK.

его превращение усиливается, so when evaluating the high-frequency characteristics of a substrate material, В ходе обзора основное внимание уделялось условиям, в которых осуществляется преобразование стоимости..

For substrate materials with high-speed and high-frequency characteristics, для характеристики преобразования высокой частоты обычный подложный материал имеет два различных типа: один тип изменяется с частотой, and its (DF) value changes very little .

другой тип материала приближается к общему подложке с точки изменения амплитуды, but its own (DF) value is lower.