PCB Tech - What kind of material do we need to choose for high-frequency boards

What kind of material do we need to choose for high-frequency boards

Generally, use FR-4 glass fiber board for frequency, but high frequency materials should be used around 1-5G frequency, such as semi-ceramic materials. The more commonly used ones are ROGERS 4350 series, 4003 series, 5880 series and so on.

If the frequency is higher than 5G, it is best to use PTFE material, that is, polytetrafluoroethylene (PTFE), this material has good high frequency performance, but the processing technology has limitations, such as hot air leveling surface technology.

Examples of selection of high-frequency board

(1) 1.9GHz radio frequency transceiver

Among them, the power amplifier adopts high-frequency board PTFE sheet, double-sided circuit board; the radio frequency transceiver adopts high-frequency board PTFE sheet, four-layer PCB board. All adopt large-area paving and isolation measures of functional module shielding cover.

(2) Selection of 2.4GHz spread spectrum digital microwave relay board

Its structure includes 2M digital interface, 20M spread spectrum despreading, 70M intermediate frequency modulation and demodulation board. We use FR4 board, four-layer PCB board, large area floor, high-frequency analog part of the power supply is isolated from the digital part by inductance choke.

The 2.4GHz radio frequency transceiver adopts F4 double-sided circuit board, and the transceiver is shielded by a metal box, and the power input is filtered.

(Iii) 70MHz intermediate frequency transceiver

Using FR4 glass fiber board, four-layer PCB board. Pave the ground in a large area, and the functional module isolation belt is isolated by a series of via holes.

(Iv) 30W power amplifier

Use RO4350 sheet, double-sided circuit board. Pave the ground in a large area, with a spacing constraint greater than or equal to 50 ohm line width, shielded by a metal box, and filtered at the input end of the power supply.

(5) 140MHz IF transceiver

The top layer is made of 0.3mm S1139 board, which is spread over a large area and is isolated by via holes.

(Vi) 2000MHz microwave frequency source

Using 0.8mm thick S1139 sheet, double-sided circuit board.

Devices in the wireless field involve a wide range of applications, and their applications are relatively complex. Especially in the current wireless communications market, the competition is fierce, and product prices and time to market have increasingly become the focus of competition. Therefore, the PCB design of electronic engineers cannot simply consider the advancement of technology, but must consider compromises from many aspects, balancing key factors such as technological advancement, price advantage and shortening the time to market, so as to improve the competitiveness of products.