What is high frequency pcb?
As complexity of electronic components increases, the one thing that becomes imperative is signal rates and high frequency of transmission. Little surprise then that the demand for high frequency PCBs is on the rise. They find use in a variety of high-speed design applications that require a frequency range of 500MHz to 2GHz.
FR-4, based on epoxy resin and glass reinforcement, is the most popular laminate material for printed circuit board industry for a long time. The FR4 dielectric constant ranges from 3.8 to 4.8, depending on the glass weave style, thickness, resin content, and copper foil roughness. However, PCB industry also use other material for different application. In RF/microwave products, low loss and special controlled dielectric constant material like PTFE (Teflon) was widely used. These material was developed long time ago. Partly because of low volume in production, it is quite expensive in the past. When wireless became popular in consumer products years ago, the demand for low loss material was went high. But the material cost is still high. Even some new developed material were trying to get involved, it seems none of them can reduce the material cost dramatically. How to reduce the RF PCB cost became an essential problem for the designer. One of the solution is the mixed dielectric design.
Because the low loss material is not needed for all wireless system, it mostly designed-in, from my understanding, for the circuits from antenna to power amplifier. To reduce the PCB cost, designer used multiple PCB and only the front end of the receiver subsystem need high cost low loss material. However, the cost is still high because of multiple PCB’s and the connector between them. Beside, the Teflon PCB is soft and is comparably difficult in assembly due to warpage.
As another kind of high frequency material, Teflon pcb are widely used in wireless networks, wireless communications and satellite communications, in particular the popularity of 3G networks exacerbate the market demand for the product on the HF PCB.