What Are the Panasonic M6 High-Speed Sheet-PCB High-Frequency Sheet?

Definition of PCB high frequency board

High-frequency circuit boards refer to special circuit boards with high electromagnetic frequencies, which are used for PCBs in the fields of high frequency (frequency greater than 300MHZ or wavelength less than 1 meter) and microwave (frequency greater than 3GHZ or wavelength less than 0.1 meters). The CCL is a circuit board produced by using part of the process of the ordinary rigid circuit board manufacturing method or using a special treatment method. Generally speaking, a high-frequency board can be defined as a circuit board with a frequency above 1GHz.

With the rapid development of science and technology, more and more devices are designed for applications in the microwave frequency band (>1GHZ) or even in the millimeter wave field (77GHZ) (such as the now very popular 77GHz millimeter wave antenna for vehicles), which also means As the frequency is getting higher and higher, the requirements for the substrate of the circuit board are also getting higher and higher. For example, the substrate material needs to have excellent electrical properties, good chemical stability, and the loss on the substrate with the increase of the power signal frequency is required to be very small, so the importance of high-frequency boards is highlighted.

Classification of PCB High Frequency Sheets

01. According to the material

a. Organic materials: phenolic resin, glass fiber/epoxy resin, Polyimide, BT/Epoxy, etc. are all included.

b. Inorganic materials: aluminum, Copper-invar-copper, ceramic, etc. belong to it. Mainly take its cooling function

02. Distinguish between flex and rigid finished products

a. Rigid PCB.

b. Flexible PCB.

c. Rigid-Flex PCB.

03. Divide by structure

a. Single-sided circuit board

b. Double-sided circuit board

c. Multilayer circuit board

04. According to the purpose

Communication/Consumable Electronics/Military/Computer/Semiconductor Test Board

Commonly used high-speed plates (manufacturers)

01. Rogers

Rogers RO4003, RO3003, RO4350, RO5880, etc.

RO3000 series: based on ceramic filled PTFE circuit materials, models are: RO3003, RO3006, RO3010, RO3035 high-frequency laminates.

RT6000 series: based on ceramic filled PTFE circuit materials, designed for electronic circuits and microwave circuits that require high dielectric constant, models are: RT6006 dielectric constant 6.15, RT6010 dielectric constant 10.2.

TMM series: composite materials based on ceramics, hydrocarbons, thermoset polymers, models: TMM3, TMM4, TMM6, TMM10, TMM10i, TMM13i. and many more

02. Taikangli

Taconic TLX series, TLY series, etc.

03. Panasonic

Panasonic Megtron4, Megtron6, etc.

Dongguan Shengyi, Taizhou Wangling, Taixing Microwave, Changzhou Zhongying, etc.

Of course, there are many other high-frequency boards that are not listed one by one. Among them, Arlon (which has been acquired by Rogers, is also an old brand RF microwave board factory).

Important indicators for selecting high-frequency and high-speed PCB materials

When selecting a substrate for a PCB used in a high-frequency circuit board, special consideration should be given to the changing characteristics of the material DK at different frequencies. For requirements that focus on high-speed signal transmission, or characteristic impedance control requirements, focus on DF and its performance under conditions such as frequency, temperature and humidity.

Under the condition of frequency change, general substrate materials show a large change in DK and DF values. Especially in the frequency from 1 MHz to 1 GHz, the changes of their DK and DF values are more obvious. For example, the DK value of the general type epoxy resin-glass fiber cloth-based substrate material (general type FR-4) at the frequency of 1MHz is 4.7, and the DK value at the frequency of 1GHz changes to 4.19. Above 1GHz, the change trend of its DK value is gentle. The trend of change is that with the increase of frequency, it becomes smaller (but the change is not large). For example, at l0GHz, the DK value of FR-4 is generally 4.15, and the substrate material with high-speed and high-frequency characteristics changes in frequency. In the case of , the change of DK value is small, from 1MHz to 1GHz change frequency, DK is mostly kept in the range of 0.02. Its DK value tends to decrease slightly under different frequency conditions from low to high.

The dielectric loss factor (DF) of the general substrate material is affected by the frequency change (especially in the high frequency range), and the change in the DF value is larger than that of the DK. Its change rule tends to increase, therefore, when evaluating the high-frequency characteristics of a substrate material, the focus of its investigation is the change of its DF value. Substrate materials with high-speed and high-frequency characteristics, in terms of changing characteristics at high frequencies, there are two distinct types of general substrate materials: one is that with the change of frequency, its (DF) value changes very little. . Another type is similar to the general substrate material in the range of change, but its own (DF) value is lower.

How to choose high frequency high speed sheet

Loss DB of different sheets

For example, the 10Gb/S high-speed digital signal is a square wave, which can be regarded as the superposition of sine wave signals of different frequencies. Therefore, 10Gb/S contains many different frequency signals: 5Ghz fundamental signal, 3rd order 15GHz, 5th order 25GHz, 7th order 35GHz signal, etc. Maintaining the integrity of the digital signal and the steepness of the upper and lower edges is the same as the low-loss and low-distortion transmission of RF microwave (the high-frequency harmonic part of the digital signal reaches the microwave frequency band). Therefore, in many respects, the requirements for PCB material selection for high-speed digital circuits are similar to those for RF microwave circuits.

In actual engineering operations, the selection of high-frequency boards seems to be simple, but there are still many factors to consider. Through the introduction of this article, as a PCB design engineer or high-speed project leader, have a certain understanding of the characteristics and selection of the board . Learn about sheet electrical properties, thermal properties, reliability, and more. And rational use of stacking, a product with high reliability and good processability is designed, and the consideration of various factors is optimized.

Key Considerations for Choosing the Right Sheet

01 Manufacturability

For example, how many times the lamination performance, temperature performance, etc., CAF/heat resistance and mechanical toughness (stickiness) (good reliability), fire rating.

02 Various properties that match the product

Low loss, stable Dk/Df parameters, low dispersion, small coefficient of variation with frequency and environment, small tolerance of material thickness and glue content (good impedance control), if the trace is long, consider low-roughness copper foil. Another point is that the design of high-speed circuits requires simulation in the early stage, and the simulation results are the reference standard for design. "Xingsen Technology-Agilent (High Speed/RF) Joint Laboratory" solved the problem of inconsistent performance between simulation results and testing. It has done a lot of closed-loop verification of simulation and actual testing, and can achieve consistency between simulation and actual measurement through a unique method.

The procurement cycle of many high-frequency boards is very long, even 2-3 months; in addition to the stock of conventional RO4350 high-frequency boards , many high-frequency boards need to be provided by customers.

03 Timely availability of materials

The procurement cycle of many high-frequency boards is very long, even 2-3 months; in addition to the stock of conventional RO4350B high-frequency boards , many high-frequency boards need to be provided by customers. Therefore, high-frequency plates need to communicate with manufacturers in advance and prepare materials as soon as possible.

04 Cost factor

Look at the price sensitivity of the product, whether it is a consumer product, or an application in communications, medical, industrial, and military industries.

05 Applicability of laws and regulations, etc.

It must be integrated with the environmental protection regulations of different countries and meet the requirements of RoHS and halogen-free.

Among the above factors, the running speed of high-speed digital circuits is the main factor for PCB selection. The higher the speed of the circuit, the smaller the selected PCB Df value should be. Boards with medium and low losses will be suitable for 10Gb/s digital circuits; boards with lower losses will be suitable for 25Gb/s digital circuits; boards with ultra-low loss will be suitable for faster high-speed digital circuits, whose rate can be 50Gb /s or higher.

From material DF:

DF is between 0.01 and 0.005. The circuit board is suitable for the upper limit of 10Gb/S digital circuit;

DF is between 0.005 and 0.003. The circuit board is suitable for the upper limit of 25Gb/S digital circuit;

Circuit boards with Df not exceeding 0.0015 are suitable for 50Gb/S or even higher-speed digital circuits.