In applications including high frequency and high speed, the demand for printed circuit boards has greatly increased. The reasons behind this are the increase in bandwidth requirements and the miniaturization of devices. To ensure complete application success, the correct type of board must be used. Of the three printed circuit board types for high performance applications, flexible printed circuit boards have been found to be the best choice.

Advantages of flexible PCB materials

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

Flex Material: While this may seem obvious, it's still an important point. High frequency applications require consistent thin film circuit layers. Various types of flexible polymer films are used to create electrical circuits. These films ensure a thin and consistent flexible layer, which makes them the best choice for high frequency applications.

Copper: The type of copper used in flexible printed circuit board manufacturing is significantly different from the copper material used in rigid circuit boards. The copper used to make flexible printed circuit boards is made by passing a large ingot through a series of rolls. The rolling process also expands and anneals the copper, resulting in large copper grains. Large grain size makes it more durable in application. Also, the copper is attached to the flexible material by adhesive rather than brazing, which can easily break.

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.