High-frequency PCB is specialized circuit boards designed for use at relatively high electromagnetic frequencies. Generally speaking, high frequency can be defined as frequencies above 1GHz. Microwave PCB is produced using a combination of conventional rigid circuit board manufacturing processes or specialized processing methods on a microwave-based copper-clad laminate. They require extremely high physical properties, precision, and technical parameters and are commonly used in automotive anti-collision systems, satellite systems, and radio systems.

With the rapid advancement of science and technology, an increasing number of devices are being designed for applications in the microwave frequency band (>1GHz) or even the millimeter wave (77GHz) range (for example, the currently popular 77GHz automotive millimeter wave antenna). This increases the frequency, placing increasingly stringent demands on the substrate material used in circuit boards. For example, the substrate material must possess excellent electrical properties, good chemical stability, and minimal losses as the power signal frequency increases. This highlights the importance of high-frequency laminates.