Patent ID: 8008994

Claim:
A filter that provides tunable capacitive coupling, the filter comprising: a housing having at least one conductive wall that defines a cavity operating at a default frequency; a conductive element extending inside said cavity from said at least one conductive wall along an axis; and a tuning assembly disposed adjacent said at least one conductive wall and separated from said conductive element by a tunable distance, said tuning assembly comprising: a hollow sleeve inserted into a recess having a specified depth along said at least one conductive wall and parallel to said axis, said hollow sleeve comprising a non-conductive material and having a particular depth, a wire having a first end inserted fully within said hollow sleeve to said particular depth and a second end bent in a direction orthogonal to said axis, thereby having said capacitive coupling fixed to a value that is proportional to said particular depth, and a dielectric disposed circumferentially around said first end of said wire, said dielectric retaining said first end of said wire within said hollow sleeve at said particular depth.