A filter circuit (1) includes a first transmission line (11), a second transmission line (12) which has an electrical length set to ½ of an electrical length of the first transmission line, a first capacitor (21), a second capacitor (22), and a third capacitor (23). Capacitances of the first capacitor, the second capacitor, and the third capacitor are set in such a manner that a circuit including the first transmission line, the second transmission line, and the first capacitor resonates in series at a predetermined fundamental frequency, a circuit including the first transmission line, the first capacitor, and the second capacitor resonates in parallel at a third harmonic frequency being a tripled frequency of the fundamental frequency, and a circuit including the second transmission line and the third capacitor resonates in series at the third harmonic frequency.

A filter circuit (1) includes a first transmission line (11), a second transmission line (12) which has an electrical length set to ½ of an electrical length of the first transmission line, a first capacitor (21), a second capacitor (22), and a third capacitor (23). Capacitances of the first capacitor, the second capacitor, and the third capacitor are set in such a manner that a circuit including the first transmission line, the second transmission line, and the first capacitor resonates in series at a predetermined fundamental frequency, a circuit including the first transmission line, the first capacitor, and the second capacitor resonates in parallel at a third harmonic frequency being a tripled frequency of the fundamental frequency, and a circuit including the second transmission line and the third capacitor resonates in series at the third harmonic frequency.

The present invention relates to a cavity filter and, in particular, provides an advantage of preventing performance deterioration of an antenna device by efficiently absorbing an assembly tolerance which may occur due to assembly design and preventing an interruption of an electrical flow, by comprising: an RF signal connecting part provided to be spaced apart at a predetermined distance from an external member having an electrode pad formed on one surface thereof; a terminal part which electrically connects the electrode pad of the external member to the RF signal connecting part, while absorbing an assembly tolerance existing within the predetermined distance and simultaneously preventing an interruption of an electrical flow between the electrode pad and the RF signal connecting part; a dielectric body which is inserted into a terminal insertion hole so as to surround the outside of the terminal part; and an elastic member which has a portion of the edge supported by the dielectric body and which elastically supports the terminal part by means of an operation in which a hollow part is deformed in the vertical direction when an assembly force is transmitted to the terminal part supported to pass through the hollow part, wherein the terminal part comprises one terminal brought into contact with the electrode pad and the other terminal connected to the RF signal connecting part.

The present invention relates to a cavity filter and, in particular, provides an advantage of preventing performance deterioration of an antenna device by efficiently absorbing an assembly tolerance which may occur due to assembly design and preventing an interruption of an electrical flow, by comprising: an RF signal connecting part provided to be spaced apart at a predetermined distance from an external member having an electrode pad formed on one surface thereof; a terminal part which electrically connects the electrode pad of the external member to the RF signal connecting part, while absorbing an assembly tolerance existing within the predetermined distance and simultaneously preventing an interruption of an electrical flow between the electrode pad and the RF signal connecting part; a dielectric body which is inserted into a terminal insertion hole so as to surround the outside of the terminal part; and an elastic member which has a portion of the edge supported by the dielectric body and which elastically supports the terminal part by means of an operation in which a hollow part is deformed in the vertical direction when an assembly force is transmitted to the terminal part supported to pass through the hollow part, wherein the terminal part comprises one terminal brought into contact with the electrode pad and the other terminal connected to the RF signal connecting part.

A multilayered filter device includes a multilayer stack, a band pass filter, a first band elimination filter, and a second band elimination filter. The band pass filter and the first and second band elimination filters are each constructed using the multilayer stack. The band pass filter includes a plurality of first resonators with open ends. Each band elimination filter includes a connection path, and a second resonator coupled to the connection path. The connection path includes an impedance transformer. The second resonator includes a conductor line constituting a distributed constant line.

A multilayered filter device includes a multilayer stack, a band pass filter, a first band elimination filter, and a second band elimination filter. The band pass filter and the first and second band elimination filters are each constructed using the multilayer stack. The band pass filter includes a plurality of first resonators with open ends. Each band elimination filter includes a connection path, and a second resonator coupled to the connection path. The connection path includes an impedance transformer. The second resonator includes a conductor line constituting a distributed constant line.

A filter comprising a flexible PCB with one or more signal tracks on one side. A electromagnetically absorbing material covers the signal tracks. An insulating material may be provided between the signal tracks and the electromagnetically absorbing material. The PCB is then folded or rolled to take up less space. The PCB may be first folded and then rolled to have both ends of the signal tracks available at the outer portion of the roll.

Described is a bandpass filter comprising a multi-layered body, a first resonator conductor formed on a first layer of the body and a second resonator conductor formed on a second, tower layer of the body. The first resonator conductor and the second resonator conductor comprise a first coupling area formed by only a partial overlap of the first resonator conductor and the second resonator conductor. A length of each said resonator conductor is in the range of λ.sub.g/3 to λ.sub.g/5, where λ.sub.g. is a center wavelength of the bandpass filter passband.

A receiver or transmitter designed for a broad range of frequencies requires a pre-select filter for incoming signals or a post-select filter for outgoing signals to minimize spurious signal responses. In conventional receivers, several discrete RF filters are used and a switched filter bank is created utilizing a large amount of space. A filter bank comprising a plurality of stacked shielded filters would enable different filter technologies and topologies to be used together, as other passive and active circuits may be combined into the one surface mountable component in order to save on PCB space.

A receiver or transmitter designed for a broad range of frequencies requires a pre-select filter for incoming signals or a post-select filter for outgoing signals to minimize spurious signal responses. In conventional receivers, several discrete RF filters are used and a switched filter bank is created utilizing a large amount of space. A filter bank comprising a plurality of stacked shielded filters would enable different filter technologies and topologies to be used together, as other passive and active circuits may be combined into the one surface mountable component in order to save on PCB space.