A study on transmission characteristic of signal line with solder-mount on a PCB

As a fundamental study of the high frequency printed circuit or wire-bonding, the transmission characteristics and magnetic near field intensity distribution for the modeled printed circuit board (PCB), which have the soldered thin wire line are investigated experimentally. The size of a modeled sample is 30×50 mm² using 1.53 mm glass-epoxy substrate. Basic signal line constructed as 50-ohm characteristic impedance. The soldered thin wire line of 100-micrometer diameter was fabricated at the center of the modeled PCB that simulates the bonding part. S-parameters, i.e. |S₂₁| and |S₁₁|, characteristic impedance measured by the time domain reflectometry and magnetic near field distribution measured by a shielded loop probe are discussed. The length of the thin wire and shape of the strip line and wire-bonding part have significant influence to the characteristic impedance, transmission property and magnetic distribution properties. These results offer the design ways and guidelines for the PCB and parts designing and wiring including solder mounted element and also wire bonding packaging at high frequency applications.