The first successful domestic cable insulation repair technology

On February 25th, the State Grid Sichuan Electric Power Company successfully used cable insulation on-site repair technology for the first time at the Zhangzhou 220 kv Lizhuang substation to implement field insulation repair of the 10 kV operating cable, indicating that China's grid cable insulation repair technology has achieved significant The breakthrough will provide technical support for solving the aging problem of urban distribution cable insulation in the future.

The cable repair technology uses the method of pressure injecting the silicone repair fluid to the core of the high voltage cable to make the repair solution chemically react with water, and the generated silicone material fills the gap of the cable tree, thereby eliminating water trees, The use of this technology is the first time in China to repair cable insulation and extend the life of the cable.

High Frequency PCB - Definition, Characteristics, Manufacturing, Materials and Application Scenarios

With the development of science and economy, the electronic industry has become an important driving force for economic development. Electronic products have become a part of life, affecting people's way of life. High-frequency circuit boards are widely used in many electronic industries and some instruments and equipment, and high-frequency PCB applications are also increasing. Choose high-frequency circuit board manufacturers in good service to buy high-quality products for use, we have to understand the relevant knowledge of high-frequency board.

High Frequency PCB

What Is A High Frequency Circuit Board?

High frequency circuit board (HF PCB) is a special circuit board with high electromagnetic frequency. Generally speaking, high frequencies can be defined as frequencies above 1GHz. Its physical performance, accuracy and technical parameters are very demanding. It is often used in automobile anti-collision system, satellite system, radio system and other fields.

High Frequency PCB include: 

  • Rogers high frequency PCB
  • Power amplifier high frequency PCB
  • Buried blind hole mixed high frequency PCB
  • Ceramic high frequency PCB
  • Ceramic mixed high frequency PCB
  • Communication antenna high frequency PCB
  • GPS antenna high frequency PCB
  • FR-4 high frequency PCB
  • Double sided high frequency PCB
  • Microwave High Frequency PCB
  • Induction High Frequency PCB
  • 2.4G Radar Induction PCB
  • 5.8G Microwave Induction PCB

High Frequency Circuit

A Practical New Patent Technology for High Frequency PCB

The utility model patented high frequency circuit board includes a core board with a hollow groove and a copper clad plate adhering to the surface and the lower surface of the core board by flow glue. The upper opening and the lower opening edges of the hollow groove are provided with a baffle.

The high frequency circuit board provided by the utility model is provided with a barrier which can block the flow glue at the upper and lower edges of the hollow groove of the core board.

In this way, the flow glue will not enter the hollow slot when the core plate is bonded with the copper clad laminate placed on the upper and lower surfaces, that is, the bonding operation can be completed by one press.

Compared with the existing technology, the high frequency circuit board can only be completed by secondary pressing. The high frequency circuit board in the utility model has the advantages of simple structure, low cost and easy manufacture.

Characteristics of High Frequency Circuit Board

Generally speaking, high frequency circuit boards have their own characteristics: low dielectric constant, relatively stable. In theory, the smaller the dielectric constant, the more stable the signal, and the higher the frequency circuit board can play a better role in signal transmission. Medium loss is very small, it is not easy to absorb water and moisture, heat resistance, corrosion resistance and other excellent performance. Conversely, if the dielectric constant is high, the signal transmission process is slow.
The thermal expansion coefficients of high frequency circuit boards and copper foil are also correlated to a certain extent. They are consistent as far as possible. The inconsistency can easily lead to the separation of copper foil in the alternate change of heat and cold. The later use will affect the signal transmission of PCB. The absorbency of high frequency circuit board is lower than that of other multi-layer circuit boards, because humidity will affect the dielectric constant and dielectric loss of high frequency circuit board. In addition, the heat resistance, chemical resistance, impact strength, peeling strength and other requirements are also good.

High frequency signals are vulnerable to noise and come with much tighter impedance tolerance as compared to conventional circuit boards.

High Frequency PCB

High Frequency Circuit Board Materials

High frequency PCB have their own unique plates. Special materials are used to attain the high frequency given by the High Frequency PCB. PCB manufacturer commonly used Materials are: rogers(Rogers 4350B HF.Rogers RO3001.Rogers RO3003).Taconic(RF-35 Ceramic.TLX). Arlon(85N).Isola(IS620 E-fibre glass).F4B.TP-2.FR-4,Dielectric constant 2.2-10.6 and so on. FR4 is the cheapest one, while Teflon is the most expensive one. But they all have a common characteristic, which is the resin used in the material. The wiring of high frequency circuit board is exquisite and has great influence on components. High-frequency signals have the strongest impact on analog devices, so we should deal with the relationship between them to achieve the best performance. Therefore, high frequency is not easy to pass through high capacity electrolytic capacitors with poor high frequency performance.

Our most common request is for FR-4 material, which is composed of woven fiberglass bound by an epoxy resin, and which we always keep stocked as one of our PCB Options at a Standard Price. FR-4 is a robust material with excellent thermal characteristics, and electrically it is known to perform quite reasonably at RF or Microwave frequency levels. 

Some clients whose designs are intended for particularly demanding applications-such as high-power or broadband circuits-find that FR-4 sometimes just does not do the job at those higher frequencies. In these cases, we are always happy to help you find a laminate material to suit your specific needs, and our highly customizable PCB Assembly Process can be easily adjusted to make sure your project lead time is not impacted.

A snapshot of the datasheet for FR-4 material is shown below for reference. 

High Frequency PCB Materials-FR4

The most popular high-frequency-specific laminate materials were developed by Rogers, and referred to with an [RO-[ prefix. These high-quality materials exhibit approximately a 20% reduction in dielectric constant, compared to standard FR-4; they also boast rather impressive thermal characteristics, with Tg values above 280°C . A snapshot of the datasheet for RO4350B and RO4003C is included below for your convenience. 

High Frequency PCB Materials-Rogers

Requirements for Manufacturing Materials of High Frequency PCB

1. Dielectric loss (Df) must be small, which mainly affects the quality of signal transmission. The smaller the dielectric loss, the smaller the signal loss.

2. Low water absorption. High water absorption will affect dielectric constant and dielectric loss when damped.

3. The dielectric constant (DK) must be small and stable. Usually the smaller the better. The transmission rate of the signal is inversely proportional to the square root of the dielectric constant of the material. High dielectric constant easily causes signal transmission delay.

4. The coefficient of thermal expansion of copper foil is the same as that of copper foil, because the inconsistency will cause the separation of copper foil in the change of cold and heat.

5. Other heat resistance, chemical resistance, impact strength and peeling strength must also be good.

Generally speaking, high frequency can be defined as frequency above 1 GHz. At present, most of the high frequencies used are fluorine dielectric substrates. Teflon is much better than other substrates, such as PTFE, which is usually called Teflon.  However, Teflon substrate has the disadvantage of high cost and large heat resisting property..

How to Make High Frequency Circuit Board?

High Frequency PCB

Fabrication Principle of High Frequency Circuit Board

In the design of high frequency circuit, the power supply is designed in the form of layers, which is much better than that in the form of buses in most cases, so that the circuit can always follow the path with the smallest impedance. In addition, the power board has to provide a signal loop for all generated and received signals on PCB, which can minimize the signal loop and reduce noise, which is often ignored by low frequency circuit designers.

In the design of high frequency PCB, we should follow the following principles:

  • Unity of power supply and ground, stability.

  • Careful wiring and proper termination can eliminate reflection.

  • Careful consideration of wiring and proper termination can reduce capacitive and inductive crosstalk.

  • Noise suppression is needed to meet EMC requirements.

Points for Attention in Manufacturing High Frequency Circuit Board

1. Impedance control is strict, relative line width control is very strict, general tolerance is about 2%.

2. Because of the special plate, the adhesion of PTH copper deposit is not high. Usually, plasma treatment equipment is needed to roughen the through-hole and surface to increase the adhesion of PTH copper and solder resist ink.

3. Do not grind the plate before welding resistance, otherwise the adhesion will be very poor, and can only be coarsened with micro-corrosive powder.

4. Most of the sheets are PTFE materials. There will be many rough edges when they are formed by ordinary milling cutters, which need special milling cutters.

5. High frequency circuit board is a special circuit board with high electromagnetic frequency. Generally speaking, high frequency can be defined as frequency above 1 GHz.

Its physical performance, accuracy and technical parameters are very demanding. It is often used in automobile anti-collision system, satellite system, radio system and other fields.

Scenario and Field of High Frequency Circuit Board Application:

  • Communication Base Station
  • Repeater
  • GPS antenna
  • Radio Frequency Antenna
  • power amplifier
  • Signal amplifier
  • Wave filter
  • coupler
  • attenuator
  • Power divider
  • 3DB Bridge, etc.
Nowadays, the high frequency of electronic equipment has become a trend of development, especially in the growing development of communication networks, aerospace, military equipment, intelligent transportation, information products are also increasingly high-speed and high-frequency. Nowadays, with the development of science and economy, many new products need high frequency circuit boards. High frequency circuit boards play an increasingly important role in people's daily life.

It is not easy to find a fast and good manufacturer of high frequency circuit boards. Jinghongyi PCB has its own unique board advantages in making high frequency circuit boards. It has reliable automatic production equipment and testing equipment.

Reasons for Choosing Jinghongyi PCB

1. Top imported raw materials for high frequency circuit boards to ensure product quality from the source

  • Plate: Shengyi, South Asia, KB.Rogers.Taconic. Isola. Arlon.F4BM.Nelco.Hitachi.
  • Potions: Rohm&Haas (US) Atotech (Germany) Umicore (Germany)
  • Ink: Taiyo (Japan) 
  • Dry membrane: Asahi (Japan), Dupont (US)

2. Full set of surface treatment equipment to meet the needs of various industries

We are one of the few companies in PCB industry equipped with complete surface treatment equipment.We can deal with the Immersion Gold completely.

Immersion Silver, Immersion tin, OSP, tin spraying, gold plating, thick gold plating, tin plating, silver plating and other related requirements.

3. Leading PCB Multilayer Circuit Board Technology Capability

  • Maximum Layer: 28 layer
  • Maximum Plate Thickness: 6.0mm
  • Maximum Thickness to Diameter Ratio 10:1
  • Maximum Copper Thickness: 6OZ
  • Maximum working plate size: 1000x610mm
  • Thinnest 4 Layer PCB : 0.33mm
  • Minimum mechanical hole/pad: 0.2/0.40mm
  • Drilling accuracy: +/-0.05mm
  • PTH Aperture Tolerance: +/-0.05mm
  • Minimum Linewidth/Line Spacing: 3mil/0.075mm

4. Strict PCB quality control system to effectively guarantee product performance

  • Strictly control according to IPC standard to ensure 100% qualified rate of shipment quality.

  • Implement quality PDCA cycle process to continuously improve product performance

  • Imported DIONEXICS-900 and Temperature Cycle Inspection Equipment from USA to ensure high reliability and stability of products

5. Top Technical Team

Eight years of focus on R&D and manufacture of high-frequency board and microwave radar RF circuit board, with a dedicated, united and tenacious R&D team, customers NPI stage products, all into the process evaluation system, meet the evaluation criteria of the project, further review by the R&D team and file a case tracking the whole process.

The staff has 3-12 years of professional and technical personnel with multi-layer circuit board experience. They have rich experience in various industry standards and process quality requirements.

6. Intimate service

Service concept: regard customers as eternal partners, develop together, only choose reputation, not customers, regardless of the size of customers, in the case of customer needs, to provide the best service.

Flexible service: We will be eager to meet the customers'needs, think what they want, and do our best to help customers solve problems, reduce losses or promote project development.

Useful Resources

High Frequency PCB

High Frequency PCB, High Frequency Circuit Board, High Frequency PCB Design, High Frequency PCB Materials

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