139 results about "Antiresonance" patented technology

A piezoelectric resonator of the present invention is structured such that on a substrate 5 having a cavity 4 formed therein, a lower electrode 3, a piezoelectric body 1, a spurious component control layer 16, and an upper electrode 2 are formed in this order from bottom up. The spurious component control layer 16 is a layer for controlling a spurious frequency, and composed of, for example, a metallic material, a dielectric material, or a piezo electric material. By additionally providing the spurious component control layer 16, it is made possible to cause variation of the spurious frequency due to unwanted variation to become greater than variation in resonance frequency of the main resonance of the piezoelectric resonator. Thus, it is possible to realize a piezoelectric resonator having an admittance frequency response where no spurious component occurs between resonance frequency fr and antiresonance frequency fa.

This invention is a method for binaural localization using a cascade of resonators and anti-resonators to implement an HRTF (head-related transfer function). The spectrum of the cascade reproduces the magnitude spectrum of a desired HRTF. The proposed method provides a considerably more computationally efficient implementation of HRTF filters with no detectable deterioration of output quality while saving memory when storing a large quantity of HRTFs due to the parameterization of its resonators and anti-resonators. Finally, the method offers additional flexibility since the resonators and anti-resonators can be manipulated individually during the design process, making it possible to interpolate smoothly between HRTFs, reduce spectral coloring or achieve higher accuracy at perceptually relevant frequency regions. These HRTF are useful in stereo enhancement and multi-channel virtual surround simulation.

A four-degrees-of-freedom (DOF) nonresonant micromachined gyroscope utilizes a dynamical amplification both in the 2-DOF drive-direction oscillator and the 2-DOF sense-direction oscillator, which are structurally decoupled, to achieve large oscillation amplitudes without resonance. The overall 4-DOF dynamical system is comprised of three proof masses. The second and third masses form the 2-DOF sense-direction oscillator. The first mass and the combination of the second and third masses form the 2-DOF drive-direction oscillator. The frequency responses of the drive and sense-mode oscillators have two resonant peaks and a flat region between the peaks. The device is nominally operated in the flat regions of the response curves belonging to the drive and sense-mode oscillators, where the gain is less sensitive to frequency fluctuations. This is achieved by designing the drive and sense anti-resonance frequencies to match.

The present invention provides a piezoelectric actuator that enjoys excellent practicality.

The piezoelectric actuator includes a piezoelectric element (2) including a sheet of piezoelectric ceramic and electrodes formed at least part of the surface of the sheet of piezoelectric ceramic, and a holding member (4) holding the piezoelectric element (2). The piezoelectric at least one of the requirements (a) to (e) described below.

• • (a) The bulk density shall be equal to or smaller than 5 g/cm³, and the Young's modulus Y₁₁^E calculated according to a resonance-antiresonance method shall be equal to or larger than 90 GPa.
  • (b) The coefficient of thermal conductivity shall be equal to or larger than 2 Wm⁻¹K⁻¹. (c) The coefficient of thermal expansion shall be equal to or larger than 3.0 ppm/° C. over a temperature range from −30° C. to 160° C.
  • (d) The pyroelectric coefficient shall be equal to or smaller than 400 μCm⁻²K⁻¹ over the temperature range from −30° C. to 160° C. (e) The mechanical quality factor Qm calculated according to the resonance-antiresonance method shall be equal to or smaller than 50 over a temperature range from −30° C. to 80° C.

The invention relates to a vehicle hanger bracket, in particular to a hydraulic interconnection ISD (Inerter-Spring-Damper) hanger bracket. Hydraulic cylinders of a rear overhang hydraulic ISD hanger bracket are reversely connected in series, namely, the upper cavity of the left side hydraulic cylinder and the lower cavity of the right side hydraulic cylinder are connected, and the lower cavity of the left side hydraulic cylinder and the upper cavity of the right side hydraulic cylinder are connected; when the bounce directions of left and right wheels are consistent, liquid interaction is realized by a connecting pipe, and the loads borne by the two side wheels are balanced; when the bounce directions of left and right wheels are inconsistent, liquid is capable of converting the pressure difference between the upper cavity and the lower cavity into an inertia force by a hydraulic motor, the dynamic stroke of the hanger bracket is reduced, and the aim of preventing sidesway of a vehicle is reached. On the basis of an antiresonance technology of the hydraulic ISD hanger bracket, and through the combination of the interconnection sidesway prevention, the hydraulic interconnection ISD hanger bracket has the advantages that for a complicated work condition road, under the premise that the riding comfort is not influenced by negative effects, the vehicle driveability is improved, the coordination control is realized for the smoothness and the handling stability, four modalities relative to the movement of a vehicle body, of wheels are independently decoupled by an interconnection hanger bracket system, and the structure is simple and reliable, the cost is low and the implementation is easy in comparison with a driving hanger bracket.

Band reject filters are disclosed. A band reject filter includes a first acoustic resonator and a second acoustic resonator, each of which has either shunt resonators adapted to resonate substantially at respective resonance frequencies defining a rejection frequency band or series resonators adapted to anti-resonate substantially at respective anti-resonance frequencies defining the rejection frequency band. These resonators are connected through a phase shifter which imparts an impedance phase shift of approximately 45° to 135°. Exemplary applications of the band reject filters disclosed herein include implementation as an inter-stage band reject filter for a base station power amplifier for a wireless communication system, as a radio frequency band reject filter in a duplexer for a wireless communication terminal, and in a low noise amplifier input stage.

There is provided a resonance circuit using piezoelectric vibrator such as a quartz resonator, a coil, a capacitor, or an element equivalent to them in combination. When two resonance circuits having different resonance frequencies are combined, it is possible to configure an oscillation circuit and a filter capable of freely adjusting the frequency characteristic by utilizing the phenomenon that by changing the excitation current or voltage of the respective resonance circuits independently from each other, antiresonance frequency of the entire composite resonance circuit can be changed.

A piezoelectric substrate and interdigital electrode portions are covered with an insulating layer with an insulating thin film interposed therebetween. The piezoelectric substrate is made of LiTaO₃ and the insulating thin film and the insulating layer are made of silicon oxide. By intentionally making the upper surface of the insulating layer flat, the deterioration of propagation efficiency of surface acoustic waves can be suppressed, so that it is possible to reduce increase in insertion loss of a resonator. Since the upper surface of the insulating layer is flat, it is also possible to reduce variation in resonant frequency and anti-resonant frequency due to the temperature change of the surface acoustic wave device.

An acoustic film resonator comprises a first piezoelectric film (101); a pair of primary electrodes (103,104) that are formed on the first piezoelectric film and to which an electric signal is applied; a second piezoelectric film (102) that is disposed such that oscillation occurring in the first piezoelectric film propagates to the second piezoelectric film; a pair of secondary electrodes (104,105) that are formed on the second piezoelectric film and that outputs an electric signal; a load (108) connected between the secondary electrodes; and a control part (109) that controls the value of the load. Thus, an acoustic film resonating element is configured wherein an electric signal from the primary electrodes is outputted from the secondary electrodes through a piezoelectric effect and wherein the resonance frequency and the antiresonance frequency can be varied by controlling the value of the load. Both the resonance frequency and the antiresonance frequency can be varied at the same time without degrading the resonance characteristic.

A SAW (Surface Acoustic Wave) filter includes serial arm resonators and parallel arm resonators interconnected in pairs in a multiple-stage, ladder configuration. A resonating device is serially connected to any one of the serial arm resonators and has an attenuation pole frequency higher than that of the serial arm resonator. At the attenuation pole frequency of the serial arm resonator, the resonating device functions as capacitance without performing attenuation. The resonating device has an antiresonance frequency 1.8 times or more but 2.2 times or less, or 2.7 times or more but 3.3 times or less, as high as the antiresonance frequency of the serial arm resonator.

The invention belongs to the technical field of fiber couplers, and particularly relates to a hollow-core antiresonance photonic crystal fiber coupler and application thereof. The fiber coupler is formed by two hollow-core antiresonance fibers with polished side faces. The basic structure of each hollow-core antiresonance fiber comprises a fiber core, a circle of micro-capillary inner covering layer around the fiber core and an outer covering layer covering the exterior of the micro-capillary inner covering layer. The polished faces of the hollow-core antiresonance fibers are arranged on the outer covering layer and are attached to each other and subjected to fusion or tapering, so a fiber coupler is manufactured. Before the tapering or during the tapering, the ring distance of two rings near the attached faces is reduced or increased, so the mode coupling of the fiber core of the two hollow-core antiresonance fibers is optimized. The fiber coupler is simple in design and highly practical, can be used for pulse laser, especially, full-fiber coupling and laser beam splitting of femtosecond laser and can be applied in a hollow-core fiber gyroscope to replace a solid fiber coupling module.

The invention discloses a gas-liquid elastic dual-frequency vibration isolator, and belongs to the technical field of vibration isolation design. The gas-liquid elastic dual-frequency vibration isolator comprises a shell, an inner cylinder, elastic rubber, a piston body, a lower cover body and an air cavity additionally-arranged air chamber; one end of the inner cylinder is arranged inside the shell, the elastic rubber is arranged between the shell and the inner cylinder, and the side face of the elastic rubber, the shell and the inner cylinder are bonded to form a sealed upper liquid cavity;anti-falling bolts are arranged in the circumferential direction of the shell to prevent the elastic rubber from falling off; one end of the inner cylinder is provided with an air compensating cavity,the air compensating cavity is provided with the piston body, a lower liquid cavity is formed between the piston body and the inner cylinder, and the lower liquid cavity communicates with the upper liquid cavity; the air compensating cavity is provided with a lower cover body in an internally screwed mode, and the cavity between the lower cover body and the piston body communicates with the air cavity additionally-arranged air chamber for changing the supporting rigidity of the piston body; and the gas-liquid elastic dual-frequency vibration isolator is arranged in a main supporting reductionrod of a helicopter through the shell and the lower cover body and used for isolating vibration. The gas-liquid elastic dual-frequency vibration isolator has the advantages that the structure is simple, the weight is small, the frequency band of vibration isolation is wide, and the dynamic stiffness of antiresonance points is low.

A hybrid multiplexer includes a filter configured to allow a high-frequency signal of an HB to pass therethrough, and a filter configured to allow a high-frequency signal of an MB to pass therethrough, in which the filter includes a matching circuit, a first resonance circuit defined by one of an LPF and an HPF, and a second resonance circuit defined by the other of the LPF and the HPF, the LPF includes an inductor and a parallel arm resonator, the HPF includes a serial arm resonator and an inductor, and a resonant frequency of the parallel arm resonator and an anti-resonant frequency of the serial arm resonator are both located between a frequency at a low-band end of the HB and a frequency at a high-band end of the HB.

Antenna duplexer (1) has first filter (3) passing a signal in a first frequency band and second filter (4) passing a signal in a second frequency band higher than the first frequency band, and first filter (3) includes series resonator (7) having the lowest antiresonance frequency and other series resonators. The propagation angle of the main elastic wave of series resonator (7) having the lowest antiresonance frequency and that of the main elastic wave of the other resonators are made different from each other so that an electromechanical coupling coefficient of series resonator (7) having the lowest antiresonance frequency becomes smaller than that of the other resonators.

An undercarriage (2) having anticrash and antiresonance skids (6) for a rotary wing aircraft (1), the undercarriage including in particular:

• • two landing skids (6) that are elastically deformable in the event of a normal landing;
  • front and rear transverse elements (7, 8) likewise elastically deformable in the event of a normal landing;
  • assembly elements (9, 14) for assembling the transverse elements to a force take-up structure (5) of the aircraft (1); and
  • a connection system (10) suitable for absorbing the energy of a crash landing by controlled plastic deformation and including at least one pair of buckling struts (11) arranged so as to deform in the plastic range by buckling, together with a fastener member (14) of the assembly elements for providing statically-redundant assembly between a structure (5) of the aircraft (1) and a respective one of the front and/or rear elements (7, 8).

The present invention discloses a large-broadband and large-angle continuous scanning optically controlling phased array antenna receiving device and method, belonging to the technical field of microwave photons. The device and the method employ a cascading microring with anti-resonance working to form a delay continuous regulation and control subunit, employs an optical switch to switch waveguides with different lengths to form a delay discrete regulation and control subunit, and an optical delay unit formed by the delay continuous regulation and control subunit and the delay discrete regulation and control subunit is configured to provide delay compensation required by receiving large-broadband and large-angle continuous scanning phased-array antenna microwave signals. The electro-optical phase modulation is employed to achieve photovoltaic conversion of the antenna receiving microwave signals, avoid usage of an offset point control circuit and simplify the system structure. The optical single side band filtering is employed to reduce the requirement for the delay unit broadband, the difference balance photoelectric detection is employed to effectively reduce the common-mode noise and improve the system performances.