255 results about "Microwave amplifiers" patented technology

A predistortion circuit for a microwave amplifier and more particularly to predistortion circuit configured as a Doherty amplifier. The predistortion circuit is adapted to be coupled to a downstream Doherty amplifier to precompensate for the gain compression and phase expansion of the downstream Doherty amplifier as the input power level is increased while simultaneously reducing the intermodulation (IM) distortion. In order to provide precompensation, the precompensation circuit is operated at bias level to provide gain expansion and phase compression to cancel out the gain compression and phase expansion of the downstream Doherty amplifier to provide a higher overall linear power added efficiency (PAE).

A common source, bi-directional microwave amplifier is described. More particularly, the present invention is a microwave, common source, bi-directional amplifier that includes a first amplification path and a second amplification path wherein the signal directional flow is controlled through the selective biasing of the first amplification path and the second amplification path. Each amplification path is designed to optimize desired performance. For signal flow through the first amplification path, the first amplification path is biased-on and the second path is biased-off. For signal flow through the second amplification path, the second amplification path is biased-on and the first path is biased-off.

A medical device includes a handle assembly including a distal end, a probe extending distally from the distal end of the handle assembly, and a microwave amplifier unit disposed within the handle assembly. The microwave amplifier unit is adapted to amplify a high-frequency input signal to generate a high-frequency output signal to be transmitted to the probe.

Masers and microwave amplifiers that can function in the continuous-wave mode at room temperature are provided. The maser system can include a diamond gain medium having nitrogen-vacancy centers, and a resonator can be disposed around the gain medium. The resonator can be disposed in a cavity box, and radiation (e.g., visible light) can be provided to the gain medium to cause emission of microwave radiation.

Disclosed is an optical time domain reflectometer simultaneously sensing temperature and stress. The system is based on parallel detection of Rayleigh and Brillouin scattered light and includes devices such as a multi-wavelength laser source, a light-pulse modulator, a balance detector, a microwave amplifier, a high-speed data acquisition card, a coupler and a circulator and the like. In the optical time domain reflectometer, the frequency interval of wavelengths of the multi-wavelength laser source is arranged to be in a range of 9-12 GHz, which is equivalent to a frequency shift quantity of Brillouin scattered light in a fiber. A heterodyne coherent detection method is used to carry out parallel detection on Rayleigh and Brillouin scattered spectra and temperature and stress information is demodulated through a Landau-Placzek ratio (LPR) and Brillouin frequency shift distribution; and at the same time, coherent Rayleigh noises are reduced and superposition of the scattered spectra improves the signal-to-noise ratio of the scattered light. The optical time domain reflectometer is capable of realizing simultaneous temperature and stress sensing of a distributed fiber sensing system, improving the signal-to-noise ratio of the scattered light and improving the sensing precision and distance.

A method of manufacturing a medical device includes the initial steps of providing a handle assembly and providing a microwave-signal-amplifying module. The handle assembly includes a handle body defining a chamber therein. The handle body is configured to support an energy applicator at the distal end thereof. The microwave-signal-amplifying module includes a microwave amplifier unit adapted to amplify a high-frequency input signal to generate a high-frequency output signal. The microwave-signal-amplifying module includes one or more connector portions including one or more electrical connectors adapted to be removeably coupleable to one or more electrical conductors associated with the handle body. The method also includes the step of positioning the microwave-signal-amplifying module into the chamber to bring the one or more electrical connectors of the one or more connector portions into electrical engagement with one or more electrical connectors associated with the handle body.

A medical device includes a handle assembly and a probe-and-amplifier assembly. The handle assembly includes a handle body defining a chamber therein. The probe-and-amplifier assembly includes a probe and a microwave amplifier unit. The probe extends distally from the distal end of the handle assembly. The microwave amplifier unit is disposed within the chamber. The microwave amplifier unit and the probe are mechanically coupled to one another to form a unitary body. The probe-and-amplifier assembly is selectively removable from the handle assembly.

A method of directing energy to tissue includes the steps of providing a handheld device including an energy applicator and a handle assembly configured to support the energy applicator at a distal end thereof, and transmitting energy from an output of a microwave amplifier unit disposed within the handle assembly through the energy applicator to tissue.

A system includes a microwave signal generator and a medical device. The medical device includes a handle assembly, a microwave-signal-amplifying module, and a probe. The microwave-signal-amplifying module includes a microwave amplifier unit. The microwave amplifier unit is adapted to amplify a high-frequency input signal to generate a high-frequency output signal. The microwave amplifier unit is disposed within the handle assembly. The probe extends distally from the distal end of the handle assembly and is operably coupled to an output of the microwave-signal-amplifying module.

A tunable-frequency photoelectric oscillation device based on a wide spectrum light source comprises the wide spectrum light source, an optical filter, a first light amplifier, a second light amplifier, a first optical fiber coupler, a second optical fiber coupler, a third optical fiber coupler, a first polarization controller, a second polarization controller, a dimming-adjustable delay line, an photoelectric modulator, a color-dispersion optical fiber, a first photoelectric detector, a second photoelectric detector, a microwave amplifier, a first optical fiber patch cord, a second optical fiber patch cord, a third optical fiber patch cord, a fourth optical fiber patch cord, a fifth optical fiber patch cord, a sixth optical fiber patch cord, a seventh optical fiber patch cord, a first cable and a second cable. The tunable-frequency photoelectric oscillation device based on the wide spectrum light source can generate wideband-adjustable microwave signals, adopts a microwave photon filter to replace a traditional point filter, overcomes the defect that a traditional photoelectric oscillator based on wide spectrum source cutting can not generate signals at certain frequency points, and has the advantages of being low in cost, adjustable in wideband, and low in phase noise.

The invention discloses a calibration method for the transmitted power of a digital microwave transceiver. The calibration method comprises the following steps of first generating a transmitted power calibration table according to transmitted power control voltages and actual radio frequency transmitted power which corresponds to the transmitted power control voltages and is transmitted by the microwave transceiver, second generating a channel calibration table, and thirdly correcting the transmitted power control voltage value in the transmitted power calibration table by using a channel correcting method. The invention further discloses a calibration circuit for achieving the calibration method for the transmitted power of the digital microwave transceiver. The calibration circuit comprises a microwave unit and a monitoring unit, and the microwave unit comprises a first power detection tube, a second power detection tube, a microwave amplifier and a microwave attenuator. The calibration circuit has the advantages of being high in batch production efficiency, high in calibration rate, high in transmitted power stability, simple in calibration method and the like.

The invention discloses a laser wavelength adjustment-based opto-electronic oscillator with a tunable frequency and a tunable broadband. The opto-electronic oscillator is characterized in that: a wavelength tunable laser, a polarization controller, a double-arm Mach-Zehnder modulator, a narrowband phase-shifted fiber grating and a high speed photoelectric detector are connected in order by fibers; and radio frequency input ports of the high speed photoelectric detector, a microwave high pass filter, a microwave amplifier, a microwave phase shifter, a microwave coupler, a microwave 3dB quadrature coupler and the double-arm Mach-Zehnder modulator are connected in order by microwave coaxial lines. Besides, a closed opto-electronic oscillation loop is formed by the double-arm Mach-Zehnder modulator, the narrowband phase-shifted fiber grating, the high speed photoelectric detector, the microwave high pass filter, the microwave amplifier, the microwave phase shifter, the microwave coupler, and the microwave 3dB quadrature coupler; and a high quality microwave signal with a tunable frequency and a tunable broadband is generated at another output port of the microwave coupler by adjustinga wavelength of the wavelength tunable laser. According to the invention, the opto-electronic oscillator has advantages of compact structure, fast frequency adjusting speed, and wide tunable frequency domain and the like.

A two-dimensional circuit for a traveling-wave tube for millimeter and sub-millimeter electromagnetic waves synchronously interacts with an electron beam in a vacuum electronic microwave amplifier or oscillator. The circuit is a solid body having a length along the tube axis. The solid body has an electrically conductive top section and an electrically conductive bottom section. The top section is configured with a plurality of vertical vanes having a width and height and configured parallel to each other. The bottom section is similarly configured such that when the circuit is viewed in cross section along the length, the vanes on the bottom section are staggered with respect to the vanes on the top section. The top section and the bottom section are separated from each other to define a tunnel through the solid body along the length.

The invention relates to a field emission triode structure based on graphene. The field emission triode structure comprises a cathode substrate (1), a support body (7) and an anode (8), wherein the support body (7) is positioned on the cathode substrate (1), the anode (8) is positioned on the support body (7) and parallel to the cathode substrate (1), and the cathode substrate (1), the support body (7) and the anode (8) constitute a cavity; and the field emission triode structure also comprises a cathode electrode (2) positioned in the enclosed cavity, a field emission body (3) for emitting electron beams (9), an insulated dielectric layer (4), a grid electrode (5) and the graphene (6). The field emission triode structure based on the graphene, provided by the invention, can realize high-current uniform emission, has the capability of effectively separating emission of field emission current from acceleration and focusing of electronic beams and can be used for a cold cathode X-ray source, a microwave amplifier tube and a field emission display.

The invention discloses a rubidium atom frequency standard digital phase locked frequency multiplier. The input terminal of the digital phase locked loop is connected with the output terminal of the rubidium atom frequency standard 10MHz voltage control crystal oscillatory as the output terminal of the frequency multiplier. The output terminal of the digital phase locked loop is connected with the output terminal of the microwave oven amplifier which is connected with the output terminal of the step matching circuit. The output terminal of the step matching circuit as the output terminal of the frequency multiplier is connected with the input terminal of the rubidium atom frequency standard microwave cavity. The phase detector and the digital frequency synthesizer are integrated by AD 9956. The invention adopts digital synthesizer as the fractional divider in which a digital phase locked loop is inserted, sets and modulate the fractional frequency division ratio of the digital synthesizer through the single chip computer thus enabling the direct fractional frequency multiplying and frequency modulation of the frequency multiplier. The invention with a simple structure, high degree of integration, high purity of the spectrum, low phase noise, small stray and high degree of digitalization is easy to modulate and can be used to produce miniaturized rubidium atom frequency standard.

A Doherty microwave amplifier having a main amplifier and a peaking amplifier, distributing and inputting an input signal to the main amplifier and the peaking amplifier to obtain an output signal by combining an output from the main amplifier and an output from the peaking amplifier, comprises a first coupler which branches and outputs a part of the input signal, a second coupler which branches and outputs a part of the output signal, and a bias control unit which feedback-controls a bias signal to the peaking amplifier, based on a difference between a level of a signal branched and output from the first coupler and a level of a signal branched and output from the second coupler.

The invention discloses an automatic compensation device of a phase noise of a Raman laser system based on closed loop feedback and a method thereof. The device comprises a laser source, a beam splitter, an electrooptical modulator, an acoustic optical modulator, a beam combiner, a half-transparent half-reflecting mirror, a phase modulator, a polarizer, a photoelectric detector, a low noise microwave amplifier, a frequency mixer, a low pass filter, an analog-digital converter, an FPGA, a digital-to-analog converter, a low frequency amplifier and a phase shifter. The automatic compensation device and method provided by the invention are capable of automatically adjusting and compensating a phase difference in the Raman laser system and reducing the phase noise caused by the vibration of a light path of the Raman laser system. By adopting the circuit control mode, the advantages of integration, modularization and easy debugging of a control system are achieved.

The invention discloses a millimeter wave signal photonics generating method based on a highly non-linear optical stimulated Brillouin scattering effect and a millimeter wave signal photonics generating device, and belongs to the technical field of microwave photonics. The device consists of a tunable laser, a first coupler, two parallel Mach - Zehnder modulator, a first DC power supply, the second DC power supply, the third DC power supply, isolators, second coupler, a first photo detector, spectrum analyzers, high nonlinear optical circulator, a second photo detector, microwave amplifiers, intensity modulator, a fourth DC power supply and a microwave signal source. The millimeter wave signal generating device according to the selected output frequency is highly nonlinear optical fiber different in 54GHz to 66GHz. Since the stimulated Brillouin frequency shift value and the wavelength of the pump light of relevant, also can adjust the wavelength tunable laser, millimeter wave signal generator output frequency of the device is adjustable within a certain range.

The present invnetion relates to a HEMT-HBT Doherty microwave amplifier and more particularly to a microwave amplifier configured as a Doherty amplifier. The amplifier includes a carrier amplifier, a peak amplifier, a Lange coupler at the input of the amplifiers and quarter wave amplifier at the output of the amplifiers. In order to further increase the efficiency, the Doherty amplifier is formed from HEMT / HBT technology to take advantage of the low-noise performance of HEMTs and the high-linearity of HBTs to form a relatively efficient amplifier that functions as a low-noise amplifier at low power levels and automatically switches to high-power amplification for relatively high-impact RF power levels.

A high-precision frequency linear-tuning narrow-linewidth laser device comprises the components of a reference crystal oscillator, a frequency / phase discriminator, a loop filter, a voltage controlled oscillator, a programmable frequency divider, a frequency multiplier, a high-speed switch, a microwave amplifier, a second low-pass filter, an analog-to-digital converter, a controller, a digital-to-analog converter, a narrow-linewidth fiber laser, an electro-optic modulator, a tunable attenuator, a tunable optical filter, a circulator, a semiconductor laser, a current driving controller, a temperature controller, etc. The high-precision frequency linear-tuning narrow-linewidth laser device settles a problem of generating a low-noise RF signal in existing high-order sideband injection locking technology, and furthermore settles a problem of synchronous current compensation to a slave laser. A problem of high-order sideband injection locking in the slave laser is settled. Furthermore the high-precision frequency linear-tuning narrow-linewidth laser device can realize functions of precise control for the output frequency of the narrow-linewidth laser, linear tuning, etc.

The invention provides a common-frequency self-interference elimination system and method of an in-band full duplex wireless communication system. The common-frequency self-interference elimination system comprises a signal transceiver module, a signal amplification and delay module, a signal modulation module, an optical fiber and a photoelectric conversion module; the signal transceiver module is used for receiving a corresponding radio frequency signal and sending the radio frequency signal to the signal amplification and delay module; the signal amplification and delay module is used for amplifying and delaying the radio frequency signal; the signal modulation module is used for eliminating a self-interference signal in the radio frequency signal to obtain a useful signal and transmitting the useful signal to the photoelectric conversion module through the optical fiber; and the photoelectric conversion module is used for converting the received useful signal into corresponding electric data and outputting the electric data. The common-frequency self-interference elimination system provided by the invention eliminates the interference signal by use of a dual drive Mach-Zehnder modulator and a voltage-controlled gain microwave amplifier, so that the coherence is excellent, and improved inhibition bandwidth and inhibition ratio performance are obtained.

The invention discloses a microwave photon up-conversion device and method based on a photoelectric oscillator and belongs to the technical field of microwave photonics. The device is composed of a laser source, a first coupler, a first circulator, a first high nonlinearity dispersion displacement optical fiber, an erbium-doped optical fiber amplifier, a first photoelectric detector, a second coupler, a first Mach-Zehnder modulator, a first microwave signal source, a first direct current voltage-stabilized power supply, an optical filter, a second Mach-Zehnder modulator, a second direct current voltage-stabilized power supply, a second circular, a second high nonlinearity dispersion displacement optical fiber, a second photoelectric detector, a microwave amplifier, a double-parallel Mach-Zehnder modulator, a third direct current voltage-stabilized power supply, a fourth direct current voltage-stabilized power supply, a fifth direct current voltage-stabilized power supply, an optical isolator and a spectrum analyzer. A Brillouin frequency shift value f of the high nonlinearity optical fiber is 9.2GHz, and a signal with frequency of f<m> can be up converted to f<m>+18.4GHz, so alow quality and low frequency intermediate signal is converted into a high quality and high frequency signal.

A materials processing system comprises a thermal processing chamber and a broadband microwave power source. The power source includes an ovenized small-signal RF circuit, a high power microwave amplifier, and forward and reflected power detectors separated from one another by an isolator. The power detectors are also preferably ovenized. A control system provides control signals to the thermally stabilized VCO and VCA in the small-signal circuit to control output power based on detected forward power compared to demanded forward power. The system may be run in either open-loop or closed-loop modes.

The invention discloses a broadband microwave signal low-phase noise synthesizing device and method. The device comprises a reference source, a fractional frequency division oscillating circuit, a broadband sampling local oscillating circuit, a sampling frequency mixer, a middle-frequency filter, a phase discriminator, a circuit integrator, a broadband microwave oscillator, a broadband microwave amplifier, an amplifier, a frequency multiplier, a narrowband filter, a high-purity-point frequency synthesizing circuit, a band-pass filter, a broadband filter, a broadband microwave frequency mixer and a low-pass filter. According to the broadband microwave signal low-phase noise synthesizing device and method, the broadband microwave signal low-noise synthesis technology according to which fixed frequency mixing, sampling and frequency mixing are combined, a traditional broadband sampling procedure is improved, namely before sampling on a feedback signal is carried out by a YIG oscillator, the feedback signal is mixed with a highly-pure local oscillation signal with the fixed frequency at first and the frequency of a local oscillation signal is converted from a high frequency into a low frequency. Then the local oscillation signal enters a sampler and undergoes sampling and frequency mixing with a sampling local oscillation signal. Thus, the sampling harmonic number can be reduced, and therefore deterioration of phase noise is relieved.

The invention discloses an online long-pulse high-power directional coupler performance testing device and method. The online long-pulse high-power directional coupler performance testing device comprises a high-power klystron system and a vector network analyzer, the output end of the vector network analyzer is connected with a micro-wave amplifier through a micro-wave switch, the output end of the micro-wave amplifier is connect with the high-power klystron system through a first direct current break device, the output end of the high-power klystron system is connected with a bi-directional coupler through a circulator, coupling output signals of the bi-directional coupler are accessed into the vector network analyzer through a micro-wave cable after passing an attenuator and the direct current break device, and the wave guide output of the bi-directional coupler is connected to a high-power water load. The online long-pulse high-power directional coupler performance testing device uses the network analyzer as a testing apparatus and uses the output signals (about 10 mW) of the network analyzer as an oscillation source of the klystron, through testing under different klystron output power and recording S21 parameters obtained by the vector network analyzer under a long-pulse (more than 1000 s) stable running condition, the global performance of the directional coupler is obtained.

Provided is a microwave-signal generating method and device based on the excited brillouin scattering effect and the optical frequency comb in high nonlinear fibers. The invention belongs to the technical field of microwave photonics. The device comprises a tunable laser, a first coupler, a second coupler, a first circulator, a second circulator, a first high nonlinear fiber, an attenuator, a fourth coupler, a first photoelectric detector, a power divider, an intensity modulator, a fourth DC voltage regulator, a first double parallel mach-zehnder modulator, a fifth DC voltage regulator, a sixth DC voltage regulator, a seventh DC voltage regulator, a third circulator, a second high nonlinear fiber, a third coupler, a second photoelectric detector, a microwave amplifier, a second double parallel mach-zehnder modulator, a first DC voltage regulator, a second DC voltage regulator, a third DC voltage regulator, an isolator, a fifth coupler, a third photoelectric detector and a frequency analyzer. Due to the advantages of mode selection and positive feedback of a photoelectric oscillator, the microwave signals which are output by the device have the advantages of good spectrum purity and low noises.

The invention discloses an optoelectronic oscillation loop-based microwave two-third frequency division method, which comprises the following steps: performing primary carrier suppression optical double-sideband modulation on a photocarrier by use of a microwave signal to be subjected to frequency division, then performing secondary carrier suppression optical double-sideband modulation on a primarily modulated optical signal by use of an oscillation signal, converting a secondarily modulated optical signal into an electrical signal by use of a photodetector, causing the electrical signal to pass through a microwave amplifier, a phase shifter and a microwave filter, dividing the electrical signal into two paths as an oscillation signal and two-third frequency division output respectively,and forming positive feedback oscillation in a two-third frequency division oscillation mode in an optoelectronic oscillation loop, thereby obtaining stable two-third frequency division output. The invention also discloses an optoelectronic oscillation loop-based microwave two-third frequency division device. According to the method and the device, two-third frequency division of any microwave signal can be implemented in an optical domain, and the advantages of great bandwidth, low noise, low spur and little interference to the outside are achieved.

The invention provides an angular speed measuring method and device based on a photoelectric oscillator. The device comprises a light source, a first polarization controller, an electrooptical modulator, an Sagnac interferometer, a photoelectric detector, a band filter, a microwave amplifier and a power divider, wherein the Sagnac interferometer comprises an optical circulator, a second polarization controller, a light beam splitter, a Sagnac ring, a rotating table and a polarizer. The method comprises the steps: measuring the frequency fosc of an oscillator signal output by the powder divider when the Sagnac ring is static, measuring the frequency f'osc of an oscillator signal output by the powder divider when the Sagnac ring rotates at the angular speed omega, and calculating the angular speed omega based on the fosc, the f'osc and the parameters of the loop circuit of the photoelectric oscillator. According to the angular speed measuring method and device based on the photoelectric oscillator, the Sagnac ring is embedded into the photoelectric oscillator, the phase change of the Sagnac ring resulted from the angular speed omega is mapped to the oscillation frequency change of the photoelectric oscillator, and simultaneously, the advantages of high-quality microwave signals produced by the photoelectric oscillator and high-resolution microwave measurement are combined, thereby greatly improving the sensitivity and resolution in measuring the angular speed omega.