Measurement of stray capacitance and inductance due to assembly variations in radio frequency circuit boards

Abstract

A microstrip directional coupler is used as a test circuit to measure the stray' capacitance and inductance due to solder flux residue deposits and solder joint geometry variations at frequencies up to 4.8 GHz. The stray capacitance is less than 50 femtofarads, and the absolute value of the stray inductance is less than 100 picohenries.