31 results about "Dual band bandpass filter" patented technology

A dual-band bandpass filter having a first pass band and a second pass band respectively corresponding to a first frequency and a second frequency. The filter includes a first pair of resonators, a second pair of resonators and a first coupling element. The first pair of resonators includes a first resonator and a second resonator, which share a first grounding transmission line and are grounded through the first grounding transmission line to generate coupling. The second pair of resonators includes a third resonator and a fourth resonator, which share a second grounding transmission line and are grounded through the second grounding transmission line to generate coupling. The first coupling element connected between the first and second pairs of resonators makes the first and second pairs of resonators produce coupling such that the dual-band bandpass filter has the first and second pass bands.

A dual-band bandpass filter with stepped-impedance resonators uses only one circuit to generate dual-band effect. It adopts the principle of stepped-impedance resonator, which contains a connecting section and two coupling sections. The impedance and electrical length of the connecting section and coupling sections conforms to a selected condition to generate two passbands at desired frequencies. A multi-layer broadside-coupled parallel lines structure may be applied to increase coupling-amount between the parallel lines so that the dual-band bandpass filters have broader bandwidth and less loss.

A fluorescence detection optical system detects fluorescence beams with two or more different wavelengths and maintains a focal position through an automatic focusing function. A multi-channel fluorescence detection apparatus includes the fluorescence detection optical system. The fluorescence detection optical system includes an automatic focusing unit which receives light reflected off a microfluidic device and determines a focal point by using an astigmatic method or a knife edge method, and an actuator which adjusts a position of an objective lens according to control of the automatic focusing unit. In addition, the fluorescence detection optical system may include a plurality of dual band pass filters, dichroic devices, etc., which provide light beams emitted from at least two light sources and transfer fluorescence generated from the microfluidic device to a photodetector.

The invention discloses a compact type UWB dual-band trap balancing band-pass filter, and belongs to the technical field of wireless communications. The compact type UWB dual-band trap balancing band-pass filter comprises a first filter, a second filter and supplement structures. The first filter and the second filter are in structural symmetry and respectively comprise a microstrip line structure formed on the upper layer of a dielectric substrate and a trough line structure formed on the lower layer of the dielectric substrate. In order to restrain common-mode harmonic waves and achieve dual-band trap characteristics, the supplement structures are additionally arranged in the microstrip line structures on the upper layers of the dielectric substrates, each supplement structure comprises a first microstrip branch knot, a second microstrip branch knot, a first harmonic oscillator, a second harmonic oscillator, a third harmonic oscillator and a fourth harmonic oscillator, wherein the first harmonic oscillator and the second harmonic oscillator are arranged on the two sides of the first microstrip branch knot in parallel, and the third harmonic oscillator and the fourth harmonic oscillator are arranged on the two sides of the second microstrip branch knot in parallel. The compact type UWB dual-band trap balancing band-pass filter has a wide different-mode signal passband and has the dual-band trap characteristics, a high common-mode restraining characteristic is achieved in the passband, the structure is compact, circuits are simple, and processing is easy.

The invention provides a GSM-R base station with high suppression of interference signals, including a base transceiver station BTS and its antenna, a pair of double band-pass filters or a pair of double band-pass filters are installed between the base transceiver station BTS and the antenna GSM-R coupler, described double-bandpass filter or double-bandpass GSM-R coupler comprises high-frequency signal insertion port RFin and radio-frequency signal port RFout, and high-frequency signal insertion port RFin is N-K radio frequency head, connects The 1 / 2 feeder is connected to the GSM‑R base station, and the RF signal port RFout is the L29 (7 / 8)‑K radio head, which is connected to the 7 / 8 feeder and connected to the antenna. The present invention compresses the receiving bandwidth of the GSM-R base station through the double-band-pass filter or the double-band-pass GSM-R coupler, reduces the floor noise level, suppresses the out-of-band large signal interference, and prevents the transceiver of the GSM-R base station Blocking, and effectively reduces intermodulation interference to GSM‑R base station transceivers.

A dual-band bandpass filter according to the present invention includes a plurality of dual-band bandpass resonators. The dual-band bandpass resonator includes a central conductor (11) having a central axis aligned with an input / output direction, a pair of grounding conductors (12), a central conductor short-circuit part (13) and a pair of stub conductors (14) that are formed on a surface of a dielectric substrate. The pair of grounding conductors are disposed on the opposite sides of the central conductor with a space interposed therebetween. The central conductor short-circuit part (13) short-circuits the pair of grounding conductors, and one end of the central conductor is connected to the central conductor short-circuit part.

The present invention discloses an improved a glazing unit comprising a glass panel which is low in reflectance for RF radiation, a coating system which is high in reflectance for RF radiation disposed on the said glass panel and creating onto the glazing unit a dual band bandpass filter. The glazing unit further comprises at least one frequencies selective decoated portion of the coating system extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Z; having a width, DW, measured along the longitudinal axis, X, and a length, DL, measured along the vertical axis, Z. The at least one frequencies selective decoated portion comprises a first decoated element comprising a plurality of unit cells forming a regular grid. The at least one frequencies selective decoated portion further comprises a plurality of second decoated elements wherein a second decoated element is placed in each unit cell of the first decoated element and wherein no second decoated element is in contact with the first decoated element.

The present invention provides a dual-band bandpass filter with high selectivity, comprising two first microstrip lines, an input end, an output end, and a second microstrip line provided on the upper surface of a dielectric slab. Both ends of each first microstrip line are provided with an open load and a shorted load, respectively; the middle parts of the two first microstrip lines are connected by means of the second microstrip line; the input end is connected to one of the first microstrip lines, and the output end is connected to the other first microstrip line; both ends of the second microstrip line are respectively communicated with the input end and the output end, and are located on the same horizontal line; the horizontal line serves as a first central axis; a second central axis is perpendicular to the first central axis; the tail end of the shorted load is provided with a shorted metal post, which is connected to a ground metal layer provided on the lower surface of the dielectric slab. The dual-band bandpass filter with high selectivity of the present invention exerts a good suppression effect on out-of-band signals, has high selectivity, introduces less noise, and avoids interference to a radio frequency front end.

The invention discloses a reconfigurable dual-band band-pass filter which comprises an upper microstrip line structure, a middle dielectric substrate, a lower grounding metal patch and a metal through hole, wherein the metal through hole penetrates through the microstrip line structure, the dielectric substrate and the grounding metal patch in sequence to enable the microstrip line structure to be connected with the grounding metal patch through the dielectric substrate; the microstrip line structure comprises a first resonator, a second resonator, a third resonator and a fourth resonator; the first resonator and the second resonator are coupled to form a group of resonators after being folded; the third resonator and the fourth resonator are coupled to form another group of resonators after being folded; through the two groups of resonators, the microstrip line structure integrally forms a grid-shaped structure; one end of each resonator is loaded with a variable capacitance diode. According to the reconfigurable dual-band band-pass filter provided by the invention, the integration level and the electromagnetic compatibility of the system are improved; two pass bands are independently reconfigurable and the absolute bandwidth is basically constant, so that the application requirement of the conventional dual-band wireless communication system can be better satisfied.

A spectrum-inspection device includes: a sensor unit array including a first sensor unit and a second sensor unit; a dual-band pass filter disposed on the sensor unit array to cover the first sensor unit and the second sensor unit, wherein the dual-band pass filter allows a first waveband and a second waveband of a light beam to pass through; and a filter disposed on the dual-band pass filter to cover the second sensor unit, wherein the filter allows wavelengths of a light beam longer than a first wavelength to pass through, wherein the first wavelength is longer than a peak wavelength of the first waveband and shorter than a peak wavelength of the second waveband.