  Several pulse compression systems have been proposed for future linear
collider. Most of these systems require hundreds of kilometers of low-loss
waveguide runs. To reduce the waveguide length and improve the efficiency of
these systems, components for multimoding, active switches and non-reciprocal
elements are being developed. In the multimoded systems a waveguide is utilized
several times by sending different signals over different modes. The multimoded
components needed for these systems have to be able to handle hundreds of
megawatts of rf power at the X-band frequency and above. Consequently, most of
these components are overmoded. We present the development of multimoded
components required for such systems. We also present the development efforts
towards overmoded active component such as switches and overmoded
non-reciprocal components such as circulators and isolators.
