Abstract
A surface mountable tunable SIW filter based on
coupled coaxial resonators is presented in this paper. A CPW
vertical transition is designed in order to provide input/output
access to the device. Biasing components are also integrated in
the same substrate and accessed through castellated via holes.
The proposed filter presents a very compact size and constant
fractional bandwidth. Measured results including the effect of
the vertical transition show low insertion losses while keeping a
constant fractional bandwidth along the tuning range.
