Coupling coefficient is a very important parameter in the design of RF/Microwave filters.
Understanding the coupling mechanism between resonators is very important for achieving a good
filter layout. This paper describes a way to classify the type of couplings exhibited in microstrip
distributed element resonators. This method explains the coupling types from the definition of
coupling coefficients. All the possible coupling types, i.e. electric coupling, magnetic coupling and
mixed coupling, will be discussed. The difference between Type-I and Type-II mixed couplings will
be addressed. A comparison between the numerically computed coupling coefficients and those
computed using computer aided design software is also presented
