Why FPC is suitable for high frequency applications

The demand for printed circuit boards (PCBs) is increasing with the development of technology, and the increase in broadband demand and the miniaturization of equipment has accelerated the application of PCB circuit boards. Correct selection of the type of PCB circuit board is the key to ensuring a complete and reliable system equipment. Of the three printed circuit board types for high frequency applications, flexible printed circuit boards have been found to be the best choice.

There are many factors that make flexible printed circuit boards ideal for high frequency applications:

Flex material:

High-frequency applications require consistent thin-film circuit layers to be applied better. Therefore, in the subsequent development of circuit boards, various types of flexible polymer films have become indispensable materials in the development of PCB circuit boards. These films ensure a thin and consistent flexible layer, which makes them the best choice for high frequency applications.

(1) Copper:

The same type required in the intelligent manufacturing of flexible circuit boards is different from conventional rigid circuit boards, which is one of the reasons why flexible printed circuit boards are suitable for high-frequency applications. Copper, made by passing a large ingot through a series of rolls, is very useful in the manufacture of flexible circuit boards. The rolling process also expands and anneals the copper, resulting in large copper grains. In flexible circuit board applications, the large grain size makes copper more suitable for this type of circuit board. Also, the copper is attached to the flexible material by adhesive rather than brazing, which can easily break.

(2) Dielectric:

This is a laminating resin with good insulating and electrical conductivity. The dielectric contains a ceramic filler that acts as an adhesive and bonds with the copper foil of the flexible circuit board. Flexible printed circuit boards are usually constructed with epoxy or acrylic adhesives. At frequencies above 1 GHz, the relative permittivity of both is high. This is why flexible materials are used for high frequency applications because of their high dielectric thickness.

The above reasons prove that flexible printed circuit boards are the best type of circuit boards for high frequency applications.