In the manufacture of high-speed PCB, the PCB must be selected to meet the design requirements, mass production, cost to strike a balance. In simple terms, the design requirements consist of electrical and structural reliability. In general, when designing very high speed PCB boards (frequencies greater than GHz), the plate issue will be important. For example, the now commonly used FR-4 material, when the frequency of several GHz, Df (Dielectricloss) will be very large, may not be applicable. There are generally several factors to consider:
manufacturability: such as multiple pressing performance, temperature performance, CAF resistance, heat resistance and mechanical toughness (viscosity), good reliability, fire rating.
and the product match a variety of performance (electrical, performance stability, etc.) : low loss, stable Dk/Df parameters, low dispersion, with frequency and environmental change coefficient is small, material thickness and rubber content tolerance is small (impedance control), if the wire is long, consider low roughness copper foil. In addition, the design of high-speed circuit needs simulation in the early stage, and the simulation result is the reference standard of the design.
the availability of materials in a timely manner: many high-frequency plate procurement cycle is very long, even 2-3 months; In addition to the conventional high-frequency plate RO4350 in stock, many high-frequency plates need to be provided by customers. Therefore, high frequency plate needs to communicate with manufacturers in advance and prepare materials as soon as possible.
Cost factor: It depends on the price sensitivity of the product, whether it is consumer products or communication, medical, industrial and military applications.
Applicability of laws and regulations: it should be integrated with environmental laws and regulations of different countries to meet RoHS and halogen-free requirements.