How to lay the circuit route of high -frequency PCB board

High -frequency circuit wiring is the focus and difficulty in the design of the PCB circuit board. Since the high -frequency signal is transmitted along the transmission line in the form of electromagnetic waves, the signal line will play an antenna. The energy of the electromagnetic field will be transmitted around the transmission line. For skewers. In order to reduce the stringing of high -frequency signals, it is necessary to comprehensively consider the impact of various aspects when wiring. So how should the high -frequency PCB be wiring? Today, the PCB assembly manufacturer will take everyone to understand.

What is high -frequency PCB

High -frequency PCB is a special circuit board with a high electromagnetic frequency, and the frequency of high frequency is above 1GHz. Various physical properties, accuracy, and technical parameters of high -frequency PCB are very high. High -frequency PCB is generally used in radar systems, satellites, antennas, honeycomb telecommunications systems -power amplifier and antenna, live satellite, E -band point -to -point microwave link, RFID identification (RFID) label, airborne and ground radar system, millimeter wave application, Missile guidance system, space satellite transceiver and other fields.

How to carry high -frequency PCB

1. Multi -layer PCB board wiring

At the PCB Layout stage, a reasonable selection of a certain number of printing board size, making full use of the middle layer to set up shielding, better achieve the nearest ground, effectively reduce the transmission length of parasitic inductors and shorten the signal, and at the same time, it can also be greatly increased Reduce the cross interference of the signal.

2. The less the lead between the feet of the electronic device, the better

The leading lead is best to use a full line, which requires a turning point. You can use a 45 -degree folding line or an arc to meet. To meet this requirement, it can reduce the transmission of high -frequency signals and coupling between each other.

3. The shorter the lead between the feet of the device, the better

The radiation intensity of the signal is directly proportional to the length of the signal line. The longer the high -frequency signal lead, the easier it is to couple on the component near it.

4. The less alternation between the leaders between the feet of the device and the better

The less holes (VIA) used during the component connection process, the better, reducing the number of holes can significantly increase the speed and reduce the possibility of data errors.

5. Pay attention to the “string disturbance” introduced by the signal line close -range parallel wiring

Since the high -frequency signal is transmitted in the form of electromagnetic waves along the transmission line, the signal line will play an antenna. The energy of the electromagnetic field will be transmitted around the transmission line. Called as string disturbances.

6. Increase high -frequency retinal capacitance at high frequency pins

The power pins of each integrated circuit block increase the nearest high -frequency retinal capacitor, which can effectively suppress the high -frequency harmonic on the feet of the power supply to form interference.

7. High -frequency digital signal ground line and analog signal ground line for isolation

Under normal circumstances, the ground line of high -frequency digital signals and the ground line of analog signals are isolated. It can be used in a suitable position in a suitable position, or a high -frequency stretching magnetic bead interconnection.

8. Avoid the circuit formed by the line

Try not to form a ring circuit as much as possible by various high -frequency signal. If it is unavoidable, the ring area should be as small as possible.

9. Ensure good signal impedance matching

During the transmission process, when the impedance is not matched, the signal will occur in the signal reflection in the transmission channel. The reflection will cause the synthetic signal to form an overwhelming, which will cause the signal to fluctuate near the logic cable.

10. Maintain the integrity of signal transmission

Maintain the integrity of signal transmission to prevent the “ground bomb phenomenon” caused by ground line segmentation.