Abstract: A cavity filter for low PIMD using hybrid cap bolts includes: a housing having therein a plurality of cavities partitioned by separation walls and an open upper portion; an upper plate coupled onto the upper portion of the housing and provided therein with a plurality of tuning bolts; a plurality of air blowing work holes formed respectively on the upper plate and outer sidewalls of the housing and corresponding to the plurality of cavities; and a plurality of hybrid cap bolts formed of different kinds of materials of metal and non-metal so as to have repulsive forces against and to be coupled to respective plurality of air blowing work holes. Thus, metal debris present inside a cavity housing are removed through an air blowing method by using an air blowing work hole formed in a cavity housing and a hybrid cap bolt for reducing PIMD.

Abstract: An RF cavity filter is disclosed. The disclosed filter includes: a housing in which there is at least one cavity formed; a cover joined to an upper portion of the housing; at least one bolt inserted through at least one through hole formed in the cover; and at least one elastic element attached to the cover in an area below the through hole, where the bolt is inserted through the through hole to provide an external force on the elastic element, and the external force alters the shape of the elastic element. With the disclosed filter, pieces of metal debris created during tuning can be prevented from reaching the inside of the filter, and the degradation in the PIMD performance that would have otherwise occurred due to the pieces of debris can be avoided. Also, the filter can maintain a tuned state without the use of separate nuts.

Abstract: A cavity filter for low PIMD using hybrid cap bolts includes: a housing having therein a plurality of cavities partitioned by separation walls and an open upper portion; an upper plate coupled onto the upper portion of the housing and provided therein with a plurality of tuning bolts; a plurality of air blowing work holes formed respectively on the upper plate and outer sidewalls of the housing and corresponding to the plurality of cavities; and a plurality of hybrid cap bolts formed of different kinds of materials of metal and non-metal so as to have repulsive forces against and to be coupled to respective plurality of air blowing work holes. Thus, metal debris present inside a cavity housing are removed through an air blowing method by using an air blowing work hole formed in a cavity housing and a hybrid cap bolt for reducing PIMD.

Abstract: An RF cavity filter is disclosed. The disclosed filter includes: a housing in which there is at least one cavity formed; a cover joined to an upper portion of the housing; at least one bolt inserted through at least one through hole formed in the cover; and at least one elastic element attached to the cover in an area below the through hole, where the bolt is inserted through the through hole to provide an external force on the elastic element, and the external force alters the shape of the elastic element. With the disclosed filter, pieces of metal debris created during tuning can be prevented from reaching the inside of the filter, and the degradation in the PIMD performance that would have otherwise occurred due to the pieces of debris can be avoided. Also, the filter can maintain a tuned state without the use of separate nuts.

Abstract: A low-noise amplifier which is equipped with at least one redundancy circuit which is connected in parallel to an amplifying circuit, so that the low-noise amplifier operates without a significant signal loss even when an abnormality takes place in the amplifying circuit and the amplifying circuit is not replaced or troubleshooted. The low-noise amplifier includes a redundancy circuit (30) effectively operable instead of an amplifying circuit (24) when the amplifying circuit (24) is in an abnormal condition, and at least one switch (22) activates the redundancy circuit (30) when the amplifying circuit (24) is abnormal. In a preferred embodiment, the redundancy circuit (30) includes a transmission line (32) for bypassing an input RF signal when the amplifying circuit (24) is in an abnormal condition. In an alternative, the redundancy circuit (30) includes a redundant amplifying circuit (34), so that the redundant amplifying circuit (34) can amplify the input RF signal in place of the amplifying circuit (24).