Metal post filter assembly using non-radiative dielectric waveguide

A metal window filter assembly using a non-radiative dielectric waveguide, comprising:

• a filter housing including parallel conductive plates facing each other;
• a filter, disposed between said parallel conductive plates, for filtering a certain frequency band of a traveling electromagnetic wave therethrough, said filter including a single body dielectric line, made from a non-radiative dielectric, whose side surface is formed with a plurality of inserting holes running parallel to said parallel conductive plates, and a plurality of metal posts, each of which having a diameter to be fittingly inserted in each of said inserting holes, said dielectric line being segmented into multi-stages by one or more sets of said inserting holes which are spaced apart by a predetermined distance along a length direction of said dielectric line, and the number of the sets corresponding to a filtering order of said filter assembly;
• and
• a plurality of tuning screws inserted, parallel to said metal posts toward said dielectric line, through both side walls of said filter housing, for tuning a resonance frequency of the filter by adjusting insertion lengths of said tuning screws,
• wherein said filter is formed with multi-staged dielectric resonators cascaded as a single body and segmented by said metal posts, a length of said multi-staged dielectric resonators is longest in a middle stage and becomes gradually and symmetrically shorter to both end stages, an impedance of said multi-staged dielectric resonators is largest in the middle stage and becomes gradually and symmetrically smaller to both end stages, and said multi-staged dielectric resonators provide a filtering function which selectively allows only the certain frequency band of the traveling electromagnetic wave to pass therethrough.