66 results about "Quarter wavelength resonator" patented technology

The invention discloses a wide-stopband LTCC (low temperature co-fired ceramic) band-pass filter based on a magnetoelectric coupling counteraction technology. The wide-stopband LTCC band-pass filter based on the magnetoelectric coupling counteraction technology comprises two quarter-wave resonators, a metal floor and a pair of feed structures, wherein the resonators and feed patches are distributed on four conductor layers; the first layer is a feed layer with large feed patches and CPW (coplanar waveguide) feed ports; the two quarter-wave resonators are distributed at the second layer and the fourth layer, and the third layer is a grounding layer; the feed patches transmit energy to the resonators by means of broadside coupling; the resonators transmit energy to each other via side coupling, magnetic coupling and electric coupling exist between the two resonators simultaneously, the coupling in intervals close to a grounding end mainly is the magnetic coupling, and the coupling in intervals close to the open-circuit ends of the resonators mainly is the electric coupling; and the position of the transmission zero point of the filter can be conveniently adjusted by adjusting the intensities of the magnetic coupling and the electric coupling. The wide-stopband LTCC band-pass filter based on the magnetoelectric coupling counteraction technology disclosed by the invention is provided with a plurality of transmission zero points, as well as is excellent in selectivity and stopband suppression performance, and compact in structure.

In accordance with an embodiment, a radio frequency transition system includes a stripline trace section with openings in ground planes and forms a quarter wavelength resonator and an electromagnetic mechanism to couple the RF energy from the stripline trace section to a connector, wherein the RF signal energy is transferred from inside a beam forming network printed wiring board to an a back side of a phased array antenna system with minimal RF losses. An RF transition system is disclosed. The RF transition system comprises a stripline trace section with openings in ground planes and forms a quarter-wavelength resonator. The RF transition system further includes an electromagnetic mechanism to couple the RF energy from the stripline trace section to a connector. The RF signal energy is transferred from inside a beam forming network printed wiring board to an a back side of a phased array antenna system with minimal RF losses.

A liner system for a steam outlet pipe of a turbine bypass system comprises a liner mounted in spaced coaxial relation to the inner pipe wall such that an annular cavity is defined between the liner and the steam outlet pipe. The cavity is open on an upstream end and closed on a downstream end such that a quarter-wavelength resonator is formed for attenuating noise associated with a flow of superheated steam passing through the steam pipe. The liner may include a plurality of perforations to further attenuate noise in the steam outlet pipe. The open upstream end and closed downstream end of the cavity increases pressure within the cavity to prevent cooling water from entering the perforations and contacting the inner pipe wall. A wire mesh disposed against the outer liner wall may block cooling water penetration through the perforations and may further attenuate noise associated with the flow of superheated steam.

A pair of balanced terminals is connected to a pair of interdigital-coupled quarter-wave resonators in an electronic device. This electronic device has a first resonance mode that resonates at a first resonance frequency f1 higher than a resonance frequency f0 in each of the pair of quarter-wave resonators when establishing no interdigital-coupling, and a second resonance mode that resonates at a second resonance frequency f2 lower than the resonance frequency f0. The second resonance frequency f2 of a low frequency is set as an operating frequency. This provides an electronic device and a filter that facilitate miniaturization and enable a balanced signal to be transmitted with superior balance characteristics.

The invention discloses a broadband three-mode Balun band-pass filter based on E multi-mode resonators, comprising an input feeder, a dual-port output feeder, a three-port output feeder, a first E multi-mode resonator, a second E multi-mode resonator, a dielectric substrate, and a metal ground plate. The first and second E multi-mode resonators are symmetrical stub-loaded multi-mode resonators. The input feeder, the dual-port output feeder, the three-port output feeder, the first E multi-mode resonator and the second E multi-mode resonator are disposed on the upper surface of the dielectric substrate, and the metal ground plate is disposed on the lower surface of the dielectric substrate. The first E multi-mode resonator includes two quarter-wave resonators and a symmetrical stub loading unit. The second E multi-mode resonator includes two quarter-wave resonators and a symmetrical stub loading unit. The broadband three-mode Balun band-pass filter has the advantages of simple structure, low loss, good selectivity and good port matching property, and is very applicable to a modern wireless communication system.

An acoustic silencer is provided by a tubular member extending along an axis and having a hollow interior defining an axial flow path therethrough. The tubular member has a sidewall with an interior face facing the hollow interior and having quarter wave resonators formed by blind holes therein.

Described are methods and systems for broad-band active reduction of noise in target spaces, such as spaces around headrests in aircraft cabins. Systems describe herein are effective over wide frequency ranges without causing undesirable amplification at any subrange ranges. Specifically, a system comprises a speaker and a resonator, both coupled to an enclosure. The interior space of the resonator is in fluid communication with the enclosed space of the enclosure, allowing the resonator to reduce the amplitude of unwanted amplification by the audio reducing sound generated by the speaker. The amplitude is reduced in a selected frequency range, which may correspond to an expected amplification for this particular system. The resonator may partially extend into the enclosure or may be completely incorporated into the enclosure. Some examples of the resonator include a Helmholtz resonator, a passive radiator, a quarter wave resonator, a pipe resonator, and an acoustic metamaterial.

A printed bandpass filter is mounted on a precision substrate to eliminate the need for post-fabrication tuning. The filter input is capacitively coupled to a series of quarter wavelength resonators and the filter output. The quarter wavelength resonators are printed as spirals to reduce filter size. The resonators define the bandpass characteristics of the filter. The filter also weakly couples the input signal to the filter output in a manner to cancel the signal image. Mechanical clips mitigate thermal stress on solder connections when the precision substrate is mounted on a second printed circuit board.

The invention discloses a substrate-insertion type rectangular waveguide band elimination filter, which belongs to the field of microwave band elimination filter. The filter is characterized in that two cavities fold to form a rectangular waveguide transmission line; a slot for inserting a medium substrate is arranged at the folding part of any one cavity; the medium substrate is electrically connected with the corresponding cavity through metal conduction bands arranged at two sides of the medium substrate and is pressed and fixed by folding of the two cavities; a plurality of L-shaped quarter-wave resonators are arranged on any one surface of the medium substrate; and each resonator is coupled with the rectangular waveguide transmission line so as to generate a stop band. According to the invention, the substrate-insertion type rectangular waveguide band elimination filter has a simple structure, does not need to use an external waveguide resonator, has low difficulty in processing and assembly and is small in volume and low in cost.

The invention discloses a dual-mode balun bandpass filter based on a multi-mode resonator, which includes an input feeder, a two-port output feeder, a three-port output feeder, a first multi-mode resonator, and a second multi-mode resonator device, dielectric substrate, metal ground plate, the first multimode resonator and the second multimode resonator are all multimode resonators loaded on the symmetry plane; the feeder at the input end, the feeder at the two-port output end, and the feeder at the three-port output end , the first multimode resonator and the second multimode resonator are located on the upper surface of the dielectric substrate, and the metal ground plate is located on the lower surface of the dielectric substrate; the first multimode resonator includes two quarter-wavelength resonators, two The symmetrical plane stub loading unit, the second multimode resonator includes two quarter-wavelength resonators and two symmetrical plane stub loading units. The balun bandpass filter of the invention has the advantages of simple structure, low loss, good selectivity and good port matching characteristics, and is very suitable for modern wireless communication systems.