This document discusses the design of coupled
resonators band-pass microwave filters. The resonators are implemented
as substrate integrated waveguide (SIW) rectangular
cavities, which are piled vertically in a multilayer board. The
coupling elements are composed by slots opened in the horizontal
metallization layers separating the resonators. Each coupling
element introduce simultaneous cross-couplings among several
resonators. The principal contribution of this work consists
on the proposal of a highly flexible design technique for the
implementation of any arbitrary coupling matrix with the
formerly described physical structure. The technique relies on
the hypothesis that the overall effect of several coupling elements
is approximately equal to the lineal combination of the effects
of the individual elements. The versatility of the proposal has
lead to the design and implementation of a variety of filters
with very different coupling matrix topologies, sharing the same
physical structure and the same type of coupling elements.
Besides, given the order of the filter, its size remains the same
despite the topology of its coupling matrix. In this document one
of these designs is discussed: a box-section filter with asymmetric
response including one transmission zero.