2. The Influence of Dielectric Constant on Material Performance
The dielectric constant of a material is determined by its manufacturer at a frequency of 1 MHz. However, it varies among materials from different manufacturers due to distinct resin content. This study employs epoxy glass cloth as a case to investigate the correlation between the dielectric constant and frequency alteration. As frequency increases, the dielectric constant decreases. Thus, in practical applications, the material’s dielectric constant should align with the operating frequency. Generally, employing the average value suffices to meet requirements. Notably, signal transmission speed within the dielectric material decreases with rising dielectric constant. Hence, to achieve high signal transmission speed, it’s imperative to reduce the dielectric constant while ensuring a high characteristic resistance value. Opting for a low dielectric constant material is essential for high characteristic resistance value selection.
3. Impact of Wire Width and Thickness on Impedance
Wire width significantly influences characteristic impedance variation. Using surface microstrip line as an example, the relationship between impedance value and wire width is elucidated. A mere 0.025mm alteration in wire width corresponds to a 5-6 ohms impedance change, as illustrated in the figure. In practical production, if 18μm copper foil is utilized to regulate signal line surface impedance, the permissible wire width variation tolerance stands at ±0.015mm. Conversely, with a 35μm copper foil for impedance control, the allowable wire width variation tolerance extends to 0.025mm. This underscores the considerable impedance value shift resulting from allowable wire width changes during production. Wire width determination by designers must meet various design prerequisites, catering not only to wire carrying capacity and temperature rise but also achieving the desired impedance value. Manufacturers must ensure that line width meets design requirements during production, altering it within the tolerance range to meet impedance specifications.
Wire thickness is determined by the required current carrying capacity of the conductor and allowable temperature rise. In production, the plating layer thickness typically averages 25μm, equating the wire thickness to the sum of copper foil thickness and plating layer thickness. Pre-electroplating, it’s crucial to ensure the wire surface is clean, devoid of residues and repairing oil black, preventing issues like un-plated copper during electroplating, which alters local wire thickness and affects characteristic impedance value. Moreover, caution must be exercised during brushing to prevent wire thickness alteration and subsequent impedance value changes.
The dielectric constant of a material is determined by its manufacturer at a frequency of 1 MHz. However, it varies among materials from different manufacturers due to distinct resin content. This study employs epoxy glass cloth as a case to investigate the correlation between the dielectric constant and frequency alteration. As frequency increases, the dielectric constant decreases. Thus, in practical applications, the material’s dielectric constant should align with the operating frequency. Generally, employing the average value suffices to meet requirements. Notably, signal transmission speed within the dielectric material decreases with rising dielectric constant. Hence, to achieve high signal transmission speed, it’s imperative to reduce the dielectric constant while ensuring a high characteristic resistance value. Opting for a low dielectric constant material is essential for high characteristic resistance value selection.
3. Impact of Wire Width and Thickness on Impedance
Wire width significantly influences characteristic impedance variation. Using surface microstrip line as an example, the relationship between impedance value and wire width is elucidated. A mere 0.025mm alteration in wire width corresponds to a 5-6 ohms impedance change, as illustrated in the figure. In practical production, if 18μm copper foil is utilized to regulate signal line surface impedance, the permissible wire width variation tolerance stands at ±0.015mm. Conversely, with a 35μm copper foil for impedance control, the allowable wire width variation tolerance extends to 0.025mm. This underscores the considerable impedance value shift resulting from allowable wire width changes during production. Wire width determination by designers must meet various design prerequisites, catering not only to wire carrying capacity and temperature rise but also achieving the desired impedance value. Manufacturers must ensure that line width meets design requirements during production, altering it within the tolerance range to meet impedance specifications.
Wire thickness is determined by the required current carrying capacity of the conductor and allowable temperature rise. In production, the plating layer thickness typically averages 25μm, equating the wire thickness to the sum of copper foil thickness and plating layer thickness. Pre-electroplating, it’s crucial to ensure the wire surface is clean, devoid of residues and repairing oil black, preventing issues like un-plated copper during electroplating, which alters local wire thickness and affects characteristic impedance value. Moreover, caution must be exercised during brushing to prevent wire thickness alteration and subsequent impedance value changes.
