Characterization of RF Micro-Coaxial Cable Insertion Loss Degradation
RF micro-coaxial insertion loss escalates through skin-depth resistance, dielectric loss tangent shifts, mechanical flex displacement, and atmospheric oxidation.
FEP Dielectric
Meaning
Fluorinated synthetic polymers provide electrical insulation and low signal attenuation in high-frequency transmission lines. Coaxial cables often employ fep dielectric to isolate conductors because of its low relative permittivity. This fluorocarbon layer maintains high signal propagation velocity across a wide frequency spectrum.
The material prevents capacitive loading in compact wiring assemblies.
Material Property
Low dissipation factor values make this material highly efficient at microwave and millimeter-wave frequencies. It exhibits a dielectric constant of approximately two point one which remains stable across temperature changes. This stability prevents impedance mismatches that cause signal distortion in RF transmission lines.
Thermal Behavior
High thermal stability allows the insulation to withstand extreme processing and operating environments. The compound resists melting during wave soldering processes and operates reliably in environments reaching two hundred degrees Celsius. This resilience prevents the internal conductors from migrating or short-circuiting under mechanical stress at elevated temperatures.
Because of this thermal endurance, the insulation maintains its dimensional stability throughout the assembly cycle.
Integration Challenge
Low surface energy complicates the bonding process between the insulating layer and metal conductors. Standard adhesives fail to adhere to the untreated surface of the material, which requires chemical etching or plasma treatment to improve wetability. Without this treatment, delamination occurs under mechanical flexing or thermal cycling.
This surface preparation step represents a major complexity in the production line of flexible cables.