478 results about "Band rejection" patented technology

A differential transmission circuit includes a grounded conductive layer, a pair of transmission line conductors, a conductive film and a via hole which connects the grounded conductive layer to the conductive film. The differential transmission circuit further includes a straight-line region which is present in the differential transmission circuit through which a differential transmission signal output by a driving circuit is transmitted and in which the pair of transmission line conductors extends parallel so as to have a first width, and a band rejection filter region in which the pair of transmission line conductors planarly overlaps the conductive film and extends parallel so as to have a second width narrower than the first width and a common mode of the differential transmission signal is attenuated at one of the frequencies which are natural number multiples of a frequency corresponding to the predetermined bit rate.

An inexpensive compact band rejection filter realizes a high sharpness of a filter characteristic at ends of passbands and has a large attenuation. In the band rejection filter, at least one of a plurality of elastic wave resonators, which contributes to formation of a transition band, has a propagation angle larger than those of the other elastic wave resonators. Accordingly, the at least one of the plurality of elastic wave resonators which contributes to the formation of the transition band has an electromechanical coupling coefficient that is smaller than electromechanical coupling coefficients of the other elastic wave resonators.

The invention discloses a filtering antenna with low profile, wide band and high gain. The antenna comprises an electromagnetic super-surface radiator and a feed part. The electromagnetic super-surface is constituted by non-uniformly small electrical units and is used as a high-efficiency radiator so that the bandwidth and gain of antenna are increased. At the same time, radiation zero points can be produced, and frequency selectivity can be increased through adjusting roll-off degree of an upper edge of a pass-band. According to the antenna, discrete micro-strip coupling slits are creatively used for feeding; metal via holes are introduced in between the micro-strip and floor; good filtering effect of low frequency stop band is guaranteed; roll-off degree of pass-band lower edges is increased. According to the invention, electromagnetic super-surface with filtering effect is creatively designed and is applied in filtering antenna; the antenna structure is simple and no complicated filtering circuit is used; The height is only 0.06[lambda]0; 10dB impedance bandwidth is 28.4%; antenna loss is low and efficiency reaches up to 95%; in-band average gain is 8.2dBi; out-band rejection is over 20dB; the stop-band is wide.

The invention relates to a multichannel low-stray-light spectrograph based on an area array detector, belonging to the field of spectral analysis instruments. The spectrograph comprises an optical platform and a light signal acquisition device, and is characterized in that the area array detector serves as the optical platform; a plurality of band-rejection filters are processed and formed along the spectrum distribution direction on the window of one channel by using an imaging film-coating method; the condition of the change of the stray light received by each area of the detector is measured in real time; and by using the channel as a reference channel, the stray light of the whole spectral analysis instrument is efficiently corrected in real time. By using the spectrograph provided by the invention, the measured stray light in a full-wave band scope of a spectral analysis system is efficiently corrected. The multichannel low-stray-light spectrograph can be applied to measuring various photo-chromic parameters, such as spectrum characteristics, absorbance value, and the like of a to-be-measured sample.

The invention discloses a complementary opening resonance ring and defect ground structure half module substrate integrated waveguide dual-band filter. The dual frequency-band filter is realized by using two resonators. The dual frequency-band filter is a complementary opening resonance ring defect ground structure which is characterized in that a top layer metal is arranged on a medium substrate, a top layer metal ground is arranged on a grounding metal surface, a complementary opening resonance ring structure is etched in the top layer metal and a grounding metal paster is etched. A line of metal through holes, microstrip lines, impedance matching units, an input feed wire and an output feed wire are arranged at one edge of the top layer metal. The complementary opening resonance ring structure can generate one passband and can generate a transmission zero point at the same time; the complementary opening resonance ring defect ground structure and the microstrip lines can generate one passband by coupling, can generate one transmission zero point at the same time and are cascaded to form the dual-band filter. According to the filter, two transmission zero points are introduced, so the out-of-band rejection is improved, the passband selectivity is improved, and the external quality factor is improved by adopting a conical gradual feeding mode.

The invention belongs to the technical field of electronic components and relates to a multi-layer chip filter and a preparation method thereof. The filter leads in ceramics and ferrite in the same chip and simultaneously realizes large inductance and large capacitance; wherein, the inductance consists of a hollow inductance (a 'magnetic core' is a ceramic material) and a magnetic core induction (the magnetic chip is ferrite material). The hollow inductance is characterized by small inductance value, large quality factor, high self-resonance frequency, and the like, thus being capable of better broadening the working frequency section of the filter; the magnetic core inductance has the characteristics of large inductance value, low self-resonance frequency, and the like, thus better reducing the in-band insertion loss of a filter with a low cut-off frequency and improving the effect of the transmission signal of the filter. The preparation method of the multi-layer chip filter includes the steps such as material preparing, casting, punching, pore filling, conductor printing, chip overlapping, isostatic pressing, gumming, sintering, etc. The filter has the advantages of small size, large rectangle degree, large out-band rejection as well as broad working frequency. The preparation method has high controllability and can be compatible with the technique of the existing chip components.

The invention discloses a YIG (Yttrium Iron Garnet) band rejection filter based on a planar resonant coupling structure and a fabrication method of the YIG band rejection filter. The filter comprises a YIG band rejection filter and a driver, wherein the YIG band rejection filter comprises a resonant cavity, a planar resonant coupling structure, a permanent-magnet biasing magnetic path and an excitation coil, the planar resonant coupling structure is arranged in the resonant cavity, and the permanent-magnet biasing magnetic path provides a stable magnetic field for the resonant cavity. With the adoption of a mode of arranging a YIG thin film on a front surface of GGG (Gadolinium gallium garnet) glass and photoetching a coplanar waveguide circuit on the YIG thin film by sputtering, the planar resonant coupling structure is formed, a traditional spherical three-dimensional coupling structured YIG band rejection resonant coupling structure is substituted, and the technical defect existing in the traditional structure is also overcome. In the processing technology, The YIG thin film is first photoetched to a required shape according to a product shape needed to fabricate, and then the GGG glass is cut along appearance; and the defect of edge breakage or damage of the YIG thin film easily caused by directly cutting the YIG thin film based on a GGG substrate is overcome.

The invention discloses a method used for inhibiting double-fed wind power plant grid connection subsynchronous oscillation. First, according to a numerical model of a grid-connected double-fed wind power plant, the frequency range of subsynchronous oscillation that may occur is determined. Then a phase compensation technology is employed for designing a corresponding band rejection filter. Finally, the designed band rejection filter is connected to a current feedback link of converter current inner loop of a rotor side of a double-fed fan. According to the invention, subsynchronous control mutual action of the double-fed wind power plant can be inhibited effectively, so that a distinct inhibition effect on double-fed wind power plant grid connection subsynchronous oscillation is realized.The method has significant realistic meaning in ensuring safe and stable operation of a power system.

A tuned resonator circuit topology is disclosed that permits implementation of narrow band-pass filters having high loaded Q and optimal coupling (for low insertion loss) using a parallel tuned resonator topology at frequencies in the 1 to 2 GHz range and beyond. The topology consists of a mirror image of the parallel tuned circuit about the signal line of a conventional parallel tuned circuit to effect a cancellation of virtually all of the induced currents between the inductive elements of the resonators. This reduction in induced currents reduces the magnetic coupling between the resonators, thereby offsetting the increase in overall coupling between the resonators as frequency increases, and thereby serves to maintain optimal coupling between the resonators as the frequency of operation increases. Moreover, the mirror image topology increases the parallelism between the inductive elements in the resonators, thereby decreasing the inductance values and permitting an increase in capacitance values. Increasing the capacitance values of the resonators effectively offsets the decrease in the loaded Q as frequency is increased. The topology works for any number of parallel resonators. As the resolution of the manufacturing process decreases (e.g. from printed circuit board to integrated circuit processes), the range of operating frequencies scales with the increase in resolution.

The invention discloses a method for the simultaneous common-frequency work of a plurality of pieces of electromagnetic equipment in a single carrier. By the method, a plurality of pieces of equipment in the single carrier with a finite area or volume can simultaneously transmit and receive electromagnetic waves to normally communicate with the outside under the conditions of same working frequency range and partial overlapping or adjacency. Digital interfaces and analogue interfaces are required by each piece of equipment, and are connected with one another for the transmission of transmitted signals of each piece of equipment. The influence of the transmitted signals on received signals can be eliminated by analogue interference suppression and digital interference suppression in a receiving flow of each piece of equipment. By the method, a frequency spectrum utilization rate can be greatly increased, requirements for a clutter and harmonic outer-of-band rejection technology can be lowered, and difficulty in system upgrading and expansion can be lowered.

The invention discloses a broadband dual-polarization base station filter antenna unit without an external filter circuit and an array thereof. The antenna unit is arranged in the middle of the reflector. The antenna comprises an oscillator arm, a balun and two parasitic metal rings. The vibrator arm is provided with a microstrip line branch, is connected through the balun, and is fed through thebalun, and the balun is provided with a feeder line. The upper part and the lower part of the vibrator arm are respectively provided with parasitic metal rings. The antenna unit has the characteristics of compact and simple structure. The invention realizes good out-of-band rejection effect and has good frequency selectivity without cascading filter, thus avoiding filter insertion loss. The invention realizes high polarization isolation, and realizes stable pattern in wide frequency band at the same time.

A dielectric filter, has a plurality of resonators; and at least one transmission line provided among said plurality of resonators, wherein a band rejection characteristic is formed around a resonance frequency of said resonator, and a line length of said transmission line is shorter than ¼ of a wavelength corresponding to the resonance frequency of said resonator.

RF telemetry for an active medical device such as active implant or programmer for such implant. The device includes at least one RF antenna (14), and at least one RF telemetry transmitter/receiver (44) with, for coupling to the antenna, an associated band rejection filter (54). The band rejection filter (54) comprises at least one volume acoustic wave BAW resonator (40) of the SMR type with insulation by Bragg acoustic reflector (42). The device can be a multi-band device comprising a plurality of RF transmitters/receivers (12, 44) operating in respective distinct bands of frequencies such as the 402˜405-MHz, 863˜870-MHz, 902˜928-MHz and 2.4-GHz bands or by UWB transmission.

The invention relates to a coupling method of a microstrip filter and a microstrip resonator thereof. The resonator comprises a group of finger-inserting capacitors comprising microstrips, a group of double-helix curved inductors and a group of blocky capacitors formed with ground, wherein the microstrip comprises an upper-layer superconducting film, a lower-layer superconducting film and an artificial monocrystal medium positioned between the upper-layer and the lower-layer superconducting films; the finger-inserting capacitors are connected in parallel with the double-helix curved inductors, and the finger-inserting capacitors and the double-helix curved inductors connected in parallel are serially connected with the blocky capacitors; a line in the finger-inserting capacitors of the first resonator, which has the same charge polarity with an outermost line of the finger-inserting capacitor of the second resonator is shortened or cut off completely; and the outermost line of the finger-inserting capacitors of the second resonator is elongated and bent, extends into a line shortened or cut off completely in the finger-inserting capacitors of the first resonator and is coupled with two adjacent lines in the finger-inserting capacitors of the first resonator. The filter has less insertion loss, large out-band rejection, high band-edge gradient and good group delay performance.

The invention relates to a characterization method and device of a tunable laser, which are used for realizing rapid and accurate characterization of the tunable laser, have universality, and are suitable for a tunable laser having an arbitrary number of control signals. The method includes the following steps: output light of the tunable laser is coupled into an optical fiber, and is then split into two paths through a beam splitter, one path passes through an optical band-pass optical filter, the other path passes through an optical band rejection filter, and central wavelengths of the optical band-pass filter and the optical band rejection filter are set at a target wavelength [lambda]0, and are then connected to a detector; control signals of the tunable laser are changed and optical power detected by the detector is collected through a computer or a microprocessor; and an initial control signal combination is generated randomly, a ratio R of the optical power P1 that passes through the optical band-pass filter and the optical power P2 that passes through the optical band rejection filter is used as a criterion for optimization, and a control signal combination required by stable output of the target wavelength [lambda]0 is searched through an optimization algorithm.

The invention discloses a double-frequency combiner with high relative bandwidth, which comprises a band rejection filter arranged on a chamber and used for enabling ultra wide band signals to pass and a band filter used for enabling relative narrow band signals to pass. The band rejection filter comprises a conduction band. The band filter comprises a plurality of harmonic oscillation columns. After the band rejection filter is combined with the band filter, the signals are output through a common port. A combination part is arranged on the harmonic oscillation column of the band filter close to the common port. The combination part is coupled with the conduction band by means of slot coupling to couple signals between the two filters. The double-frequency combiner with high relative bandwidth widens the range of use of the combiner, and overcomes the limitation that the conventional combined can only be used in the mobile communication system; in addition, as sufficient gaps are reserved between the internal parts, the power capability is improved. Furthermore, the invention has the advantages of high electric indices, low cost, simple process and the like.

The present disclosure relates to an illumination system for endoscopic applications comprising at least one substantially monochromatic light source having a predefined central wavelength between 400 and 500 nm or between 500 and 550 nm, an optical transmission path adapted to guide light emanating from the light source to an endoscopic region of examination, and an optical band-rejection filter, wherein the illumination system is adapted to illuminate at least a part of the region of examination by generating autofluorescence in surrounding tissue, and the band-rejection filter is adapted to attenuate at least said light source wavelength to a viewer and wherein said light source is the single light source in the illumination system. A further embodiment relates to an endoscope for examining a body cavity comprising tissue, the endoscope comprising a source of light consisting of a substantially monochromatic light source having a predefined central wavelength between 400 and 550 nm, means for guiding light from the substantially monochromatic light source towards at least a part of the tissue, and at least one band-rejection filter adapted to attenuate at least said central wavelength, wherein the substantially monochromatic light source is configured to generate autofluorescence in the irradiated tissue such that the irradiated tissue is observable, and wherein the endoscope is configured to display at least a part of the irradiated tissue through said band-rejection filter. A system for photodynamic diagnosis and/or therapy of bladder cancer is further disclosed herein.

An antenna system includes a first antenna, a second antenna, a band rejection filter, and a dielectric substrate. The band rejection filter is substantially disposed between the first antenna and the second antenna. The band rejection filter includes a protruded ground element, a main branch, a first extension branch, a first additional branch, and a second additional branch. The main branch substantially has a T-shape. The first extension branch is coupled to the main branch. The first additional branch is separated from the main branch, and a first coupling gap is formed between the first additional branch and the main branch. The second additional branch is separated from the main branch, and a second coupling gap is formed between the second additional branch and the first extension branch. The band rejection filter is configured to improve the isolation between the first antenna and the second antenna.