DUAL-MODE DIELECTRIC LOADED CAVITY FILTER WITH NONADJACENT MODE COUPLINGS

摘要

DUAL-MODE DIELECTRIC LOADED CAVITY FILTER WITHNONADJACENT MODE COUPLINGSAbstractAn electromagnetic cavity filter (10) is formed by atleast two cavities (12) having electrically conductivewalls (40, 15). When more than two cavities (12) areemployed, their midpoints do not have to be colinear;rather, it is sufficient that the angle formed by themidpoints of any three successively coupled cavities is anintegral multiple of 90°. Thus, a folded "engine block"geometry can be realized such that the filter's inputcavity (12) is proximate to the output cavity (12). Thisallows a canonic filter response. Each cavity (12) is theequivalent to two filter poles because two orthogonal modesof electromagnetic radiation can resonate therewithin.Electrically nonadjacent modes of proximate cavities (12),as well as electrically adjacent modes, can be coupled,permitting elliptic filter functions. Electricallynonadjacent modes are coupled by means of an iris (30)opening between the two cavities (12). Electricallyadjacent modes are coupled by means of an electricallyconductive probe (22) penetrating each of the two cavities(12). A dielectric resonator (20) can be disposed withineach cavity (12) to reduce the physical size of the cavity(12) while preserving its electrical characteristics.