What is High Frequency PCB?

General Introduction of High Frequency PCB

High-frequency 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 copper plate 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. 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 (30GHZ), which means that the frequency is getting higher and higher, and the demand for base materials is also getting higher and higher, especially in the wireless networks. Satellite communication is growing rapidly, information products are moving towards high speed and high frequency. Therefore, developing new products always need to use high frequency substrate, satellite system, mobile telephone receiving base station and so on, these communication products must use high frequency PCB.

The Features of high frequency PCB

1.The DK should be small and stable enough, usually the smaller the better, a high DK may cause signal transmission delays.

2. The DF should be small, which mainly affects the quality of signal transmission. The smaller the DF, the smaller the signal loss.

3. The thermal expansion coefficient should be the same as the copper foil as much as possible, because the difference will cause the copper foil to separate in the hot and cold changes.

4. The water absorption rate must be low. High water absorption rate will affect DK and DF in a humid environment.

5. Heat resistance, chemical resistance, impact resistance and peeling resistance must be good.

Materials for High Frequency Circuit Boards as shown in the picture below:

High frequency circuit board processing attention points:

1. The impedance control requirements are relatively strict, and the relative line width control is very strict, with a general tolerance of about 2%.

2. Due to the special plate, the adhesion of PTH copper sinking is not high. Usually, it is necessary to use plasma treatment equipment to roughen the vias and the surface to increase the adhesion of PTH hole copper and solder resist ink.

3. Do not grind the board before making the solder mask, otherwise the adhesion will be very poor, and it can only be roughened with micro-erosion potion.

4.Most of the plates are PTFE materials, and there will be many burrs when forming with ordinary milling cutters, so special milling cutters are required.

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

Its physical properties, precision, and technical parameters are very demanding, and are often used in automotive anti-collision systems, satellite systems, radio systems and other fields.

When we are producing high frequency circuit boards, we should pay attention to the following matters:

1. Reasonable selection of the number of layers: When wiring high-frequency circuit boards, using the middle inner plane as the power and ground layers can reduce parasitic inductance, shorten the length of signal lines, and reduce cross-interference between signals. Generally speaking, the noise of 4-layer PCB is 20dB lower than that of several double-layer PCB.

2. Routing method: In PCB design, when routing high-frequency circuit boards, the routing must be at a 45° angle, which can reduce the transmission and mutual coupling of high-frequency signals.

3. The total length of the trace: In PCB design, the shorter the total length of the trace, the better, and the shorter the parallel spacing between the two wires, the better.

4. Number of vias: In PCB design, the fewer the number of vias, the better.

5. The direction of the inter-layer traces: In the PCB (high frequency circuit board) formulation, the direction of the inter-layer traces should be vertical, that is, the top layer is in the horizontal direction, and the bottom layer is in the vertical direction to reduce the influence of signals on each other.

6. Copper plating: In the design of PCB (high frequency circuit board), the interference between signals can be reduced by adding ground copper foil.

7. Grounding: In the PCB design, when the high-frequency circuit board is routed, the anti-interference ability of the signal can be significantly improved by processing the grounding of the important signal lines. Of course, the interference source can also be encapsulated to prevent interference with other signals.

8. Power line: In the design of a high-frequency circuit board (microwave radio frequency board), when the high-frequency circuit board is routed, the signal traces cannot generate loops, and must be laid out in a daisy chain.

9. Decoupling capacitor: In the design of a high frequency circuit board (microwave RF board), when the high frequency circuit board is routed, the decoupling capacitor is bridged at the power supply end of the integrated circuit.

10. High frequency choke: In PCB design, when wiring the high frequency circuit board (microwave radio frequency board), the high frequency choke device needs to be connected when the digital ground wire and the analog ground wire are connected, usually through the center hole High frequency ferrite beads.

High Frequency PCB Manufacturing Capabilities

No. Category High-Frequency PCB Capabilities
1 Material RO4003C, RO4350B, Ro3003, Ro3010, RT5880
2 Number of Layers 1-40 Layers
3 Min. Track/Spacing
4 Min. Hole Size
5 Board Thickness
6 Finish Cooper
7 Silkscreen
Green, Red, Yellow, White, Black, Blue, Purple
8 Via Process
Tenting Vias,Plugged Vias,Vias not covered
9 Testing
Fly Probe Testing (Free) and A.O.I. testing
10 Surface Finishing
HASL, HASL lead free, Immersion gold(ENIG), Immersion Tin, OSP, Immersion Silver(Ag)
11 Solder Mask
Green, Red, Yellow, White, Black, Blue, Purple
12 Build Time
8-11 days
13 Delivery Time 3-4 days

Choose AllWinPcba for your High Frequency PCB

AllWinPcba provides one-to-one service to better suit your need of high frequency PCB manufacturing. We welcome your inquiry about our high frequency PCB: svc@allwinpcba.com

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