The invention discloses a LTCC wide stopband filtering balun based on discriminating coupling. The filtering balun includes a dielectric, and a first resonator, a second resonator, a first feeding line, a second feeding line, a third feeding line and a metal ground which are arranged inside the dielectric. The two resonators are both half-wavelength resonators distributed on different layers, and the layers are connected through metal through holes. the first feeding line is coupled with a specific area of the first resonator for performing feeding to suppress a second harmonic, and the second feeding line and the third feeding line are coupled with a specific area of the second resonator for performing feeding to suppress a third harmonic, thus realizing a wide stopband filtering performance. The second feeding line and the third feeding line are symmetrically arranged about a center of the second resonator, thus realizing a same-amplitude reverse-phase balun output characteristic. The LTCC wide stopband filtering balun based on discriminating coupling according to the invention can suppress the second harmonic and the third harmonic, and a LTCC multi-layer circuit technology used reduces a size of a filtering balun.

The invention discloses a LTCC wide stopband filtering balun based on discriminating coupling. The filtering balun includes a dielectric, and a first resonator, a second resonator, a first feeding line, a second feeding line, a third feeding line and a metal ground which are arranged inside the dielectric. The two resonators are both half-wavelength resonators distributed on different layers, and the layers are connected through metal through holes. the first feeding line is coupled with a specific area of the first resonator for performing feeding to suppress a second harmonic, and the second feeding line and the third feeding line are coupled with a specific area of the second resonator for performing feeding to suppress a third harmonic, thus realizing a wide stopband filtering performance. The second feeding line and the third feeding line are symmetrically arranged about a center of the second resonator, thus realizing a same-amplitude reverse-phase balun output characteristic. The LTCC wide stopband filtering balun based on discriminating coupling according to the invention can suppress the second harmonic and the third harmonic, and a LTCC multi-layer circuit technology used reduces a size of a filtering balun.

A band-stop filter comprises: a housing having a top wall, a bottom wall and at least one side wall, the housing defining an internal cavity; a signal input port and a signal output port that are respectively disposed on one of the at least one side wall; a resonating element that is disposed in the internal cavity and includes a top, a bottom, and a side; and a transmission line that is disposed in the internal cavity and coupled between the signal input port and the signal output port, the transmission line comprising a coupling section that is coupled to the resonating element, wherein the coupling section is configured to surround more than half of the side of the resonating element and not directly contact the housing and the resonating element.

A band-stop filter comprises: a housing having a top wall, a bottom wall and at least one side wall, the housing defining an internal cavity; a signal input port and a signal output port that are respectively disposed on one of the at least one side wall; a resonating element that is disposed in the internal cavity and includes a top, a bottom, and a side; and a transmission line that is disposed in the internal cavity and coupled between the signal input port and the signal output port, the transmission line comprising a coupling section that is coupled to the resonating element, wherein the coupling section is configured to surround more than half of the side of the resonating element and not directly contact the housing and the resonating element.

A cavity-type radio frequency filter is disclosed. the radio frequency filter having a cavity structure including an enclosure, a resonant element, a cover, a frequency tuning screw, and a resilient fixing member. The enclosure has a hollow inside and an open surface on one side to have a cavity. The resonant element is positioned in the hollow of the enclosure. The cover has a screw hole having a preset diameter at a position corresponding to the resonant element, and is configured to seal the open surface of the enclosure. The frequency tuning screw is configured to be screwed into the screw hole of the cover, and it has an upper end formed at least partially with a latching abutment that protrudes outwardly.

The present disclosure relates to a waveguide section having at least one air-filled waveguide conducting tube having an electrically conducting inner wall. Each waveguide conducting tube has a plug-in filter device with two or more electrically conducting elements arranged in series and spaced apart by a connecting arrangement. Each plug-in filter device is adapted to be retained in the corresponding waveguide conducting tube using a dielectric holding arrangement such that the electrically conducting elements are spaced apart from the waveguide conducting tube. The electrically conducting elements are arranged to be electromagnetically coupled such that passing a radio frequency is electromagnetically filtered.

A tunable filter for adjustable filtering between a minimum frequency and a maximum frequency includes a transmission line designed to transmit a signal and having longitudinal axis. The tunable filter further includes a two-dimensional capacitor array including step-tunable capacitors located along the transmission line, a first dimension of the two-dimensional capacitor array being along the longitudinal axis and a second dimension of the two-dimensional capacitor array being located perpendicular to the longitudinal axis. The tunable filter further includes a controller coupled to each of the step-tunable capacitors and designed to control each of the step-tunable capacitors independently to be in a biased mode or in an unbiased mode based on a desired frequency response of the tunable filter.

The invention discloses a LTCC wide stopband filtering balun based on discriminating coupling. The filtering balun includes a dielectric, and a first resonator, a second resonator, a first feeding line, a second feeding line, a third feeding line and a metal ground which are arranged inside the dielectric. The two resonators are both half-wavelength resonators distributed on different layers, and the layers are connected through metal through holes. the first feeding line is coupled with a specific area of the first resonator for performing feeding to suppress a second harmonic, and the second feeding line and the third feeding line are coupled with a specific area of the second resonator for performing feeding to suppress a third harmonic, thus realizing a wide stopband filtering performance. The second feeding line and the third feeding line are symmetrically arranged about a center of the second resonator, thus realizing a same-amplitude reverse-phase balun output characteristic. The LTCC wide stopband filtering balun based on discriminating coupling according to the invention can suppress the second harmonic and the third harmonic, and a LTCC multi-layer circuit technology used reduces a size of a filtering balun.

The invention discloses a LTCC wide stopband filtering balun based on discriminating coupling. The filtering balun includes a dielectric, and a first resonator, a second resonator, a first feeding line, a second feeding line, a third feeding line and a metal ground which are arranged inside the dielectric. The two resonators are both half-wavelength resonators distributed on different layers, and the layers are connected through metal through holes. the first feeding line is coupled with a specific area of the first resonator for performing feeding to suppress a second harmonic, and the second feeding line and the third feeding line are coupled with a specific area of the second resonator for performing feeding to suppress a third harmonic, thus realizing a wide stopband filtering performance. The second feeding line and the third feeding line are symmetrically arranged about a center of the second resonator, thus realizing a same-amplitude reverse-phase balun output characteristic. The LTCC wide stopband filtering balun based on discriminating coupling according to the invention can suppress the second harmonic and the third harmonic, and a LTCC multi-layer circuit technology used reduces a size of a filtering balun.

Filter arrangement comprising an inner electric conductor comprising at least one inner conductor segment, an outer electric conductor at least partly surrounding the inner conductor, at least one dielectric element and at least one coil spring. The at least one dielectric element is arranged sandwiched between at least one inner conductor segment and the outer conductor to form a capacitance between the outer conductor and the inner conductor segment. The at least one coil spring is arranged inside said outer conductor to force the inner conductor segment and the at least one dielectric element against the outer conductor. The at least one coil spring is made from an electrically conducting material to form an inductance and is electrically connected with the inner conductor segment. An antenna feeding network and a multi-radiator antenna comprising such a filter arrangement is also provided.