Improvements in losses and size of frequency tunable coplanar filter structures using MMIC negative resistance chips for multistandard mobile communication systems

A new band-pass filter design technique is presented that uses coplanar passive interdigitated filters assisted by an MMIC active component which performs a negative resistance with an associated imaginary part in order to compensate for the losses of the passive filter and to reduce significantly the length of the resonators. A tunable version of the filter is also presented.