58results about How to "Adjustable working frequency" patented technology

The invention discloses a magnetic coupling resonant wireless electric energy transmission device based on a low frequency PWM rectifier. The device comprises a rectifier, a voltage stabilizing capacitor, an inverter power switch, an emission circuit resonant capacitor, an emission circuit resonant coil, an emission circuit current sampling resistor, a receiving circuit resonant coil, a receiving circuit current sampling resistor, a rectifier power switch, a resonant filter capacitor, a resonant filter inductor, a load resistor, a transmitting end signal conditioning circuit, a transmitting end analog to digital converter, a transmitting end microprocessor, a transmitting end high frequency inverter driving circuit, an induction voltage detection coil, a receiving end signal conditioning circuit, a receiving end analog to digital converter, a receiving end microprocessor and a PWM rectifier driving circuit. According to the device, the resonance of an emission loop is ensured, the tracking of transmitting end working frequency, the resonance of a receiving circuit and the constant output of load voltage are realized, the requirement of working frequency by a power switch device is greatly reduced, and a space is provided for the device to raise power supply working frequency.

The invention relates to a novel multi-stable ultrasonic detection sensor which is used in the field of ultrasonic detection and includes: an acoustic resistance matching layer, a metal electrode, a piezoelectric film, a high-voltage-resistant insulating layer, a hollow chamber sealing layer, a back lining layer, and an electromechanical control circuit board. The ultrasonic detection sensor can achieve a multi-stable working mode of combination of piezoelectric ultrasonic sensing and capacitive ultrasonic sensing on one ultrasonic transducer unit through the electromechanical control circuit board, wherein each stable working mode can be designed according to optional ultrasonic frequencies, for example, a design scheme of capacitive low frequency ultrasonic sensing and piezoelectric high frequency ultrasonic sensing, thus considering both the depth and resolution of ultrasonic detection. The multi-stable ultrasonic detection sensor can be flexibly applied in ultrasonic detection on gas-phase, liquid-phase and solid-phase mediums, is simple in resistance matching, is small in size and is easy to integrate, can be produced in large scale and is low in cost, and has application prospects in the fields of underwater acoustic detection, bio-medical imaging, industrial ultrasonic non-destructive testing, etc.

The invention provides an electric adjusting power divider with a filter function. The entire circuit structure of the electric adjusting power divider is symmetric, and the power dividing ratio is 1:1. Two pairs of quarter-wave resonators which are coupled with each other form two filter networks, and the characteristic of band-pass filtering is achieved. The matching of three ports of a circuit and the isolating of two output ports of the circuit are achieved by resistors. According to an on-load variable capacitance diode, the electrical length of the resonators and the electrical length of a feeder line are adjusted by changing the on-load voltage of the on-load variable capacitance diode, and the purpose that the center frequency is adjustable is achieved. In addition, three transmission zeros are introduced by source load coupling, so that the electric adjusting power divider has high selectivity and is also good in stopband suppression effect.

The invention discloses a tunable unidirectional microwave cloaking device. The tunable unidirectional microwave cloaking device includes a first metal opening resonance ring array, a second metal opening resonance ring array, a plurality of variable capacitance diodes which correspondingly are arranged at the opening of each first metal opening resonance ring in the first metal opening resonance ring array and at the opening of each second metal opening resonance ring in the second metal opening resonance ring array, a direct-current voltage-stabilized power supply, and a controller, wherein the controller is used for controlling the output voltage of the direct-current voltage-stabilized power supply to regulate end voltage at two ends of each variable capacitance diode so as to change the capacitance values of the variable capacitance diodes, so that a frequency characteristic curve can be shifted. According to the cloaking device provided by the embodiment of the invention, control on electromagnetic wave transmission paths and phases can be realized through the resonance effects of the metal resonance rings, and obstacles in a cloaking region can be cloaked, and the frequency characteristic curve of the device can be shifted, so that the cloaking of electromagnetic wave waves in different frequency bands can be realized. The tunable unidirectional microwave cloaking device has the advantages of simple structure and easiness in control.

The invention discloses an adjustable multi-frequency slot antenna which comprises a substrate, a slot type rectangular earth plate and an impedance matching input transmission line. The slot type rectangular earth plate and the impedance matching input transmission line are arranged on the upper surface of the substrate, the slot type rectangular earth plate is provided with a middle rectangular slot, a left large rectangular slot, a right large rectangular slot, a first left adjustable rectangular slot, a second left adjustable rectangular slot, a third left adjustable rectangular slot, a first right adjustable rectangular slot, a second right adjustable rectangular slot and a third right adjustable rectangular slot, the first left adjustable rectangular slot and the first right adjustable rectangular slot are respectively provided with a first switch, the second left adjustable rectangular slot and the second right adjustable rectangular slot are respectively provided with a second switch, and the third left adjustable rectangular slot and the third right adjustable rectangular slot are respectively provided with a third switch. The adjustable multi-frequency slot antenna has the advantages of being small in size, adjustable in frequency, easy to manufacture and the like.

The invention relates to a waveguide and microwave transition circuit with adjustable working frequency. The problem in the prior art that the dimensional tolerance of the waveguide and microwave transition circuit is small and the working frequency thereof is not adjustable is solved. A polytetrafluoroethylene (PTFE) sleeve is inserted into a metal cylindrical channel. One end of the PTFE sleeve completely contacts the lower surface of a micro-strip circuit, and the other end of the PTFE sleeve completely contacts the lower surface of a waveguide through hole. The centers of a circular through hole, an insulating through hole and the PTFE sleeve correspond to one another in the vertical direction. The front end of a metal probe is inserted into the PTFE sleeve through the circular through hole of a circular metal bonding pad, and the tail end of the metal probe is fixedly installed on the micro-strip circuit. A rectangular metal block is movably installed at the tail end of the output of the waveguide through hole, and the cross section of the rectangular metal block is of the same shape and size as that of the waveguide through hole. According to the invention, microwave signals in different frequency bands can be transmitted between a rectangular waveguide and a micro-strip transmission line. The waveguide and microwave transition circuit has the characteristics of large circuit dimension tolerance and adjustable working frequency.

The invention relates to a microfluid-controlled frequency adjustable microstrip patch antenna. The antenna comprises two oppositely-disposed substrates and microfluid channels into which a microfluid can be injected; one of the substrates is provided with a radiating unit in the form of a patch; clad copper arranged on the other substrate is adopted as reflection ground; a feed structure vertically passes through the two substrates and feeds electricity to the radiation unit; and the microfluid channels are arranged between the two substrates and are located in an electric field distribution area corresponding to the radiating unit; and the microfluid channels are perpendicular to the centering surface of the radiating unit where the feed structure is located. According to the microfluid-controlled frequency adjustable microstrip patch antenna of the invention, the microfluid is injected into the microfluid channels, so that an effective dielectric constant between the radiating unit and the reflection ground can be increased, and therefore, the operating frequency of the antenna can be adjusted so as to be lowered; and the adjustable frequency range of the antenna can be controlled through loading the locations of the microfluid channels; and the reversibility of such adjustment can be realized through exhausting the microfluid channels. According to the microfluid-controlled frequency adjustable microstrip patch antenna, the adjustability of the frequency of the antenna can be realized safely and effectively at low cost, and the size of the antenna is not increased, and the integrity of the patch of the antenna is not damaged.

The invention relates to a stroboflash-free sectional type constant-current LED driving circuit. The stroboflash-free sectional type constant-current LED driving circuit comprises an LC low-pass filtering circuit, a rectification filtering circuit, a bridge inversion circuit, an LC resonance filtering circuit and a sectional type constant-current LED driving circuit. The sectional type constant-current LED driving circuit is enabled to have quite high versatility and adaptability, and the application scope of a sectional type driving scheme in the field of LED illumination is expanded.

The invention discloses a half-mode substrate integrated waveguide liquid crystal adjustable filter with embedded coupling metal wires. The filter comprises a half-mode substrate integrated waveguide, the half-mode substrate integrated waveguide comprises a dielectric substrate assembly, the dielectric substrate assembly comprises a first metal layer and a second metal layer arranged opposite to the first metal layer, the first metal layer and the second metal layer are connected through a plurality of metal through holes, the plurality of metal through holes form a through hole array to form a substrate integrated guided electromagnetic wave structure in the dielectric substrate assembly, a double-internal rotation type open-loop resonance structure is etched on the first metal layer, the double-internal rotation type open-loop resonance structure comprises two end points which are symmetrically arranged, and the two end points spirally extend towards the interior of the ring at the same time, so that each edge part of the double internal rotation type open-loop resonance structure at least comprises two etching lines. According to the half-mode substrate integrated waveguide liquid crystal adjustable filter with the embedded coupling metal wires, miniaturization of an existing filter can be achieved, and meanwhile the problem that the working frequency of the filter is fixed and cannot be adjusted is solved.

The invention discloses a low-noise amplifier, which comprises at least one spiral coil, a plurality of control switches and an amplifier tube, wherein the spiral coil is formed by a conducting wire in a winding way, the different positions of the conducting wire are provided with a plurality of leading-out end points, one end of the conducting wire is used as the input end of an input matching inductor and the leading-out end points are used as the output ends of the input matching inductor; the control switches are correspondingly connected with the leading-out end points and are turned on or off according to control signals to lead out the leading-out end points at different positions of the input matching inductor, so as to switch the inductance of the input matching inductor; and the amplifier tube is connected with the output ends of the control switches. By adopting the technical scheme, the low-noise amplifier can work at different frequencies.

The invention relates to a low-noise amplifier with an adjustable working frequency in a UHF (ultra-high-frequency) RFID (Radio Frequency Identification) reader, improving linearity by adopting a second-order intermodulation current injection structure at an input terminal and realizing an adjustable central working frequency by adopting a switched capacitor structure at an output terminal. The second-order intermodulation current injection structure acquires an injection current value when a third-order intermodulation current value is zero by analyzing the nonlinearity characteristic of a MOS (Metal Oxide Semiconductor) tube; and a switched capacitor is formed by connecting the MOS tube and a capacitor at the output terminal. The capacitor is switched on when the MOS tube is conducted, and the capacitor is switched off when the MOS is cut off, i.e. the capacitor value is changed at the output terminal by conducting or cutting off the MOS. According to the known, when an inductor value L is unchanged, and a capacitor value C is changed, the central working frequency can vary with the capacitor value C so as to adjust the central working frequency of the low-noise amplifier. A frequency mixer proposed by the invention has a working voltage of 1.2 V and low power, accords with the requirements for low voltage and low power consumption and has great instruction meanings in aspects of simplifying a circuit structure, lowering the power consumption, expanding a central working frequency point, and the like.

The invention discloses a non-refrigeration terahertz detector with an adjustable working frequency. The terahertz detector is composed of a metal-medium-metal structure and a substrate, and comprisesa metal microstructure, a medium cavity layer, a metal thin film layer, a matching layer and a flexible substrate layer from the top to bottom. The thickness of the medium cavity layer and the size and shape of the metal microstructure can adjust the detection frequency of the terahertz detector. The terahertz detector does not need an extra absorption material, and does not need refrigeration and has the prominent advantages of heat insulation performance, polarization selection and the like; and the terahertz detector has a series of advantages of simple structure, easy realization of large-area preparation, wavelength adjustability, flexible and bendable properties and the like, and has a high application prospect in terahertz signal detection.

The invention relates to a microfluid frequency reconfigurable quasi-yagi antenna based on a dielectric resonator. The antenna comprises a dielectric substrate, a reflector, a driving unit, a differential feed network, and insulating tubes which are symmetrically arranged based on the center line of the antenna and vertically penetrate through the driving unit and the dielectric substrate, the working frequency of the antenna is adjusted by injecting liquid into the insulating tubes, the liquid injection states of the symmetrical insulating tubes are consistent, and the liquid injection statesinclude a full liquid injection state and a non-liquid injection state. The invention provides a frequency reconfigurable quasi-yagi antenna adopting a dielectric resonator working in a high-order TE3[delta]1 mode for the first time. According to the electric field distribution of a TE3[delta]1 mode, a place with a relatively strong electric field is selected as a position of four air holes penetrating through the dielectric resonator to load the insulating tubes so as to obtain a relatively large frequency tuning range. The working frequency of the antenna can be effectively adjusted by injecting purified water into the symmetrical insulating tubes in sequence.

The present invention discloses a PMMA (polymethyl methacrylate) thin plate bending vibration-based elastic SV-wave filter and a filtering method. The PMMA thin plate bending vibration-based elastic SV-wave filter comprises at least two base bodies which are arranged at intervals and polymethyl methacrylate thin plates which are connected between two adjacent base bodies; a plurality of polymethyl methacrylate thin plates are arranged equidistantly along the thickness direction of the polymethyl methacrylate thin plates; each of the polymethyl methacrylate thin plates is perpendicular to the connection surfaces of the base bodies; and the thickness of each of the polymethyl methacrylate thin plates is h; the length of the polymethyl methacrylate thin plates is a distance L between the corresponding two adjacent base bodies; and L/h is greater than or equal to 5. The PMMA (polymethyl methacrylate) thin plate bending vibration-based elastic SV-wave filter of the invention has the advantages of simple configuration, low manufacturing cost and adjustable operation frequency. The filtering method of the invention can be applied to narrow-pass band elastic SV-waves.

The invention provides a nonreciprocal power divider and an electromagnetic wave transmission device. The nonreciprocal power divider comprises a dielectric substrate and at least one Wilkinson powerdivider, wherein a port of the Wilkinson power divider is used as a radio frequency port of the nonreciprocal power divider; the Wilkinson power divider is arranged on the top surface of the dielectric substrate, each branch of the Wilkinson power divider comprises a filter, and each filter is composed of at least two resonators; the back surface of the dielectric substrate is provided with a plurality of variable capacitance diodes, a plurality of signal feed-in circuits, a plurality of metallized through holes and a plurality of modulation ports; the modulation ports are used for receiving modulation signals, each modulation port is connected to one metallized through hole through the signal feed-in circuit, one end of each variable capacitance diode is connected to one end of a resonator through the metallized through hole, and the other end of each variable capacitance diode is grounded. The non-reciprocal power divider is realized without bias of any magnetic material, and has theadvantages of integration with a circuit and the like.

The embodiment of the invention discloses a method for inhibiting EMI and an EMI filter. The realization of the method comprises the following steps: obtaining the frequency points needing to inhibit the EMI, calculating the biasing voltage required by the EMI of the frequency points, arranging the biasing voltage at a variable capacitance diode connected in series with the EMI device (one end ofthe variable capacitance diode is connected with the EMI device and the other end thereof is grounded.), and utilizing the EMI device and the variable capacitance diode to inhibit the EMI of the frequency points. By increasing the variable capacitance diodes connected in series with the EMI device and changing the biasing voltage of the variable capacitance diodes, the EMI filter can work at different working frequencies so that the working frequency of the EMI filter is adjustable and the purpose of inhibiting the EMI at multiple frequency points can be realized. With realizing the purpose of inhibiting the EMI of multiple frequency points, the circuit is simplified and the cost is saved.

The invention discloses a high-voltage plasma discharge power supply device based on STM32 adjustable voltage, include the main circuit, Button and display circuit, A control circuit and a power supply circuit, the main circuit includes a rectifier bridge, Filter capacitor, inverter circuit, Hall voltage sensor, Hall current sensor and boost transformer, A control circuit includes a STM 32 minimumsystem, download circuit, serial communication circuit, An overcurrent protection circuit, a remote start-stop control circuit, a soft start control circuit, a SPI FLASH circuit, an overheat protection circuit, an undervoltage protection circuit, a PWM driving circuit, an ADC conversion circuit, a voltage-current conversion circuit and a frequency detection circuit, and a key and display circuitcomprise a key, an indicator light and an LCD display screen; The invention can improve the production efficiency, the processing quality and the production safety, meanwhile, the circuit of the invention adds a plurality of protective circuits to increase the reliability.