The dielectric constant (Dk value) is the core electrical performance parameter of high-frequency printed circuit board materials, which directly determines signal transmission speed, signal attenuation degree, impedance matching effect, high-frequency signal stability and overall working performance of high-frequency electronic equipment. Reasonable selection of high-frequency PCB material dielectric constant needs to comprehensively consider equipment working frequency band, signal transmission demand, impedance design standard, application scenario, temperature change range and production cost budget, and follow scientific selection principles and industry design specifications.

First of all, in low-to-medium high-frequency working scenarios with working frequency below 3GHz, such as ordinary wireless communication modules, short-distance signal transmission equipment and conventional radio frequency control circuits, high-frequency PCB materials with medium dielectric constant ranging from 3.5 to 4.5 are preferred. Such materials have balanced comprehensive performance, stable Dk value in low and medium frequency bands, low signal transmission loss, mature processing technology and moderate production cost, which can fully meet daily high-frequency signal transmission requirements, and will not cause excessive signal delay and impedance deviation due to too high or too low dielectric constant.

Secondly, for medium and high frequency equipment with working frequency ranging from 3GHz to 10GHz including 5G communication base station auxiliary circuit boards, high-frequency radar sensing circuit boards and wireless radio frequency receiving and transmitting modules, it is necessary to select high-frequency PCB materials with low dielectric constant between 2.2 and 3.3. Lower dielectric constant can effectively reduce high-frequency signal transmission loss, accelerate signal propagation speed, optimize signal phase stability, reduce signal distortion and crosstalk interference, and ensure high-precision stable transmission of high-frequency radio frequency signals in long-distance transmission links.

In ultra-high frequency professional electronic equipment above 10GHz such as satellite communication equipment, aerospace high-frequency signal boards, precision microwave detection instruments and millimeter wave communication circuit boards, ultra-low dielectric constant high-frequency PCB materials with Dk value below 2.2 must be adopted. Ultra-low dielectric constant can greatly suppress high-frequency signal attenuation, guarantee accurate impedance matching of ultra-high frequency circuits, adapt to complex high-frequency electromagnetic environment, and avoid signal energy loss and frequency offset caused by excessive dielectric constant.

In addition, the temperature stability of dielectric constant must be taken into priority consideration. For outdoor high-frequency equipment and industrial high-frequency control equipment with large ambient temperature variation, select high-frequency materials with small dielectric constant temperature drift coefficient, ensuring that the Dk value remains stable in high and low temperature environments without obvious fluctuation. For high-precision impedance customized circuit boards, strictly match the accurate dielectric constant according to impedance design formulas, and avoid blindly pursuing too low or too high dielectric constant leading to increased production difficulty and excessive cost waste.