45 results about "Gain bandwidth" patented technology

The invention discloses a broadband and high-efficiency true time delay reflective array antenna, and belongs to the technical field of antenna engineering. Through the design of the broadband horn feed antenna, the broadband butterfly-shaped dipole antenna and the real-time-delay coaxial transmission line, high-efficiency directional radiation is realized. The gain bandwidth of the multi-layer patch type reflective array antenna is much larger than that of a traditional multi-layer patch type reflective array antenna; compared with a traditional transmission line phase modulation type reflective array antenna, due to stable time delay and shielding and no resonant structure, the antenna has better gain stability, and an in-band gain curve is increased approximately linearly. Finally, the antenna is simple in structure and can be realized only by a single-layer patch structure and a common coaxial transmission cable, and high-cost laminated patch processing is not needed.

The invention discloses a method, device and equipment for determining parameters of a proportional resonance controller and a medium, the proportional resonance controller is applied to a current controller of a three-phase grid-connected inverter, the parameters of the proportional resonance controller comprise a proportionality coefficient, a first damping coefficient and a second damping coefficient, the first damping coefficient is greater than the second damping coefficient, and the second damping coefficient is greater than the first damping coefficient. The three-phase grid-connected inverter further comprises a filter. The proportional resonance controller is low in parameter coupling, can be independently designed, and is simple in engineering implementation; in the target open-loop transfer function, the proportionality coefficient determines the basic proportional gain, the damping coefficient controls the attenuation speed of the corresponding resonance factor, the difference between the first damping coefficient and the second damping coefficient can influence the gain bandwidth, and the larger the difference between the first damping coefficient and the second damping coefficient is, the more significant the attenuation speed difference between the second resonance factor and the first resonance factor is. The wider the high gain interval at the specific frequency of the power grid is, the higher gain is still kept even if the frequency of the power grid fluctuates, and the adaptability and robustness to the frequency deviation of the power grid are improved.

Disclosed is a novel dipole antenna design having symmetric poles, each pole having a half circle resonator and an oval resonator that are electrically connected by a straight choke section; the dipole shape permits a wideband dipole response with a transition frequency between a lower and upper frequency band. A cross bar and capacitively-coupled stubs tune at the transition frequency to create a continuous impedance and gain-bandwidth. The dipole and the crossbar and stubs are formed on opposite surface or sides of a substate. Data demonstrates the novel dipole antenna can exceed the gain-bandwidth of the state-of-the-art bowtie by approximately 5 times, that is, its gain-bandwidth is 10:1 versus the standard bowtie gain-bandwidth of 2:1 at broadside.

The invention discloses a defect coupling low-noise amplifier. The low-noise amplifier solves the problem that the performance of a low-noise amplifier in the prior art is influenced by a grid source inductance coupling coefficient. Forward coupling of an input inductor and a grid inductor and reverse coupling of the input inductor and a source inductor are achieved through a unique defect coupling transformer matching network, meanwhile, reverse coupling of a grid inductor and the source inductor is achieved, and the coupling coefficient of the grid-source inductor is reduced through coupling counteracting inductance; by combining a differential common-source transconductance amplification stage, a four-order magnetic coupling resonance unit, a differential transconductance amplification stage with a neutralizing capacitor and an output transformer matching network, the characteristics of high gain bandwidth and low noise are realized; simulation and actual tests verify that the low-noise amplifier can effectively reduce the noise coefficient and broaden the input matching range, has good compatibility and wide application prospects based on a conventional integrated circuit production process, can be applied to a phased array system, and can also form a receiver system with other circuits.

The invention belongs to the technical field of stability compensation circuits, and particularly relates to a stability compensation circuit structure of a high-speed operational amplifier, which is characterized by comprising a function module, a first control module, a second control module, a third control module, a fourth control module and a fourth control module, and the function module comprises an input stage, a differential common-base gain stage, a common-base level converter module and an output stage, and the stability compensation assembly comprises a dual-frequency load unit which is matched with the functional module and comprises a low-frequency load branch and a high-frequency load branch which are connected in parallel. Through the synergistic effect of the double-frequency load unit and the pole regulation and control capacitor, gain segmentation regulation and control of low-frequency high gain and high-frequency fast attenuation are achieved, the open-loop gain of the operational amplifier breaks through the limitation of 30dB of an existing HBT single-stage operational amplifier, and meanwhile the problem that high-frequency phase shift changes too fast is effectively restrained; through simulation verification, the phase margin can reach 67 degrees, the stability requirement of 45-60 degrees and above of an analog circuit is met, and the core contradiction that the high-gain bandwidth and the phase margin of an HBT device are difficult to balance is thoroughly overcome.

This invention discloses a high-overload data analysis method and system based on multi-dimensional buffer protection, relating to the field of data acquisition and storage technology. The system consists of several functional modules, including: a transient impedance module, which acquires stress wave propagation parameters and material strain data collected in real time by the recorder node, constructs a dynamic digital twin model of the buffer structure, and outputs impact feature vectors and stress field distribution matrices; a signal reconstruction module, which dynamically configures the sensing signals based on the impact feature vectors, including the gain, bandwidth, and filtering parameters of the analog front end, conditions and performs analog-to-digital conversion on the sensing signals, and uses compressed sensing and dictionary learning algorithms to sparsely reconstruct abnormal data, generating a high-fidelity data stream and storage data integrity identifiers for each storage block; and a federated storage module, which inputs the stress field distribution matrix and storage data integrity identifiers into the edge-side reinforcement learning decision engine to calculate the failure risk probability of each storage block.

The invention provides a current multiplexing type output amplifier. The current multiplexing type output amplifier comprises a current multiplexing type input stage, a first self-biased diode pair, a second self-biased diode pair, a first AB type output stage and a second AB type output stage, wherein the first self-biased diode pair and the second self-biased diode pair are connected with the current multiplexing type input stage; the first AB type output stage is connected with the first self-biased diode pair; according to the invention, two self-biased diode pairs are adopted to replace a floating voltage source in the prior art. When a large pulse signal is input, one diode in each of the two diode pairs is in a cut-off state, transient change current I only flows into or out of the output end from a certain branch, and compared with a traditional amplifier, the slew rate is multiplied under the same bias current condition. In addition, the input stage adopts a current multiplexing type architecture combining a PMOS (P-channel Metal Oxide Semiconductor) and an NMOS (N-channel Metal Oxide Semiconductor), under the same bias current, the equivalent input transconductance is the sum of the transconductance of the PMOS and the transconductance of the NMOS, and the unity gain bandwidth is also multiplied.

This invention discloses a broadband circularly polarized integrated feed transmission array antenna covering the entire Ka-band, comprising an array surface and an integrated feed. The phase center of the integrated feed coincides with the focal point of the array surface, illuminating the array surface perpendicularly and forming a 45-degree angle with the array surface in the horizontal direction. The array surface comprises multiple array elements of different sizes arranged linearly. Each array element includes two orthogonally arranged first and second dielectric substrates, which have the same height but different thicknesses. The integrated feed comprises a stacked first and second PCB board. A substrate integrated waveguide is disposed on the first PCB board with coupling slots, and a substrate integrated waveguide cavity and annular metal patches surrounding the substrate integrated waveguide cavity are disposed on the second PCB board. This invention achieves a wide axial ratio bandwidth and gain bandwidth, and has the advantages of low profile, light weight, easy fabrication, and low cost.

The application belongs to the technical field of laser materials, and relates to a holmium-praseodymium-scandium doped composite calcium fluoride single crystal as well as a preparation method and application thereof. 0.01 Pr x Sc y Ca 0.99‑x‑y F 2.01+x+y , wherein 0.005 <= x <= 0.015, 0.005 <= y <= 0.05; the crystal is obtained by growing the crystal in a vacuum environment through a temperature gradient method. Compared with the prior art, the application can realize high-efficiency laser output in a 2-3 mu m mid-infrared wave band, the grown crystal has the characteristics of high thermal conductivity, high chemical stability, high transmittance and high quality, and has the advantages of high gain bandwidth, high gain cross section, high power and high slope efficiency in the mid-infrared wave band, and has significant advantages in the fields of environmental monitoring, industrial processing, national defense and safety.

The invention provides an ultra-wide-band gain spectrum epitaxial material structure of a tunable laser and application of the ultra-wide-band gain spectrum epitaxial material structure. The epitaxial material structure comprises a substrate, a lower cladding, a waveguide layer, an upper limiting layer, an upper cladding and a contact layer which are sequentially arranged from bottom to top, the waveguide layer comprises an intrinsic waveguide layer and a bismuth compound quantum dot layer embedded in the intrinsic waveguide layer, and the gain bandwidth is widened through the energy band anti-cross effect instead of suppressing radiation recombination. The epitaxial material structure grows in a molecular beam epitaxy or metal organic vapor phase epitaxy mode, and the crystal quality is optimized in combination with a rapid thermal annealing process. By regulating and controlling the number of layers of the quantum dots and the bismuth component, the ultra-wideband gain spectrum coverage from near ultraviolet to near infrared bands is realized, the gain spectrum is wide, the gain peak value of the material is relatively high, and meanwhile, the material has a low linewidth enhancement factor and high temperature stability. The epitaxial material structure can be monolithically integrated in a DFB laser array and a semiconductor optical amplifier, and a core gain medium is provided for a high-performance tunable semiconductor laser.

The invention relates to a femtosecond pulse generation system and method, and the system comprises a pulse seed source which is used for generating a seed pulse; the gain management nonlinear amplification module is used for performing nonlinear spectrum broadening on the seed pulse and accumulating linear chirp, and the gain management nonlinear amplification module is configured to enable the seed pulse to undergo nonlinear self-phase modulation and dynamic gain synergistic effect to form a nonlinear attractor; the stretcher is used for carrying out time domain broadening on the pulse subjected to spectrum broadening; the at least one-stage amplifier is used for performing power amplification on the pulse after the time domain broadening; and the compressor is used for carrying out time domain compression on the pulse and outputting the compressed femtosecond pulse. According to the femtosecond pulse generation system and method, the limitation of gain bandwidth on output pulse width in the traditional chirped pulse amplification technology can be broken through, and high-power femtosecond pulses with the pulse width smaller than 100 fs can be directly output.

A dual-polarized or circularly polarized microstrip antenna employs a multi-layer stacked structure, comprising a feed layer, an upper dielectric substrate, a radiating layer, a prepreg layer, a lower dielectric substrate, and a ground layer connected sequentially from top to bottom. The upper dielectric substrate, radiating layer, prepreg layer, lower dielectric substrate, and ground layer are all square structures with chamfered corners. Rectangular slots are formed at the center edges of the four sides of the squares in the upper dielectric substrate, radiating layer, and prepreg layer. This invention introduces differential feeding, forming a ring structure with openings in the radiating layer and slots along ±45° directions. Radiation through these slots excites higher-order modes, resulting in higher gain. This antenna has a simple structure, is easy to manufacture, and offers significantly improved performance. It exhibits good impedance and gain bandwidth within the operating frequency band, low sidelobes, strong directivity, and high polarization purity. Furthermore, depending on the power divider applied, it can achieve either dual-polarized or circularly polarized operating modes.

The utility model relates to the technical field of folded antennas, in particular to a metasurface folded antenna with broadband wave beam scanning capability, which comprises a reconfigurable metasurface, a polarization conversion metasurface and a linear polarization feed source antenna, and is characterized in that the reconfigurable metasurface comprises a first dielectric plate, a second dielectric plate, a first metal grating, a second metal grating and a first metasurface; the polarization conversion metasurface comprises a third dielectric plate and two second metasurfaces, the linear polarization feed source antenna comprises a fourth dielectric plate, a fifth dielectric plate, a third metasurface, a fourth metasurface and a metal bottom plate, and the metasurfaces convert spherical waves emitted by an antenna feed source into plane waves through phase compensation. According to the array antenna, a plane wave is converted into a scannable low-SLL pencil-shaped light beam, the contour of the array antenna is reduced by 2 / 3, a simulation experiment test shows that + / -50-degree beam scanning can be realized on an E surface and an H surface within the broadband range of 8.1-11.3 GHz, the peak gain is 17.8 dBi, the aperture efficiency is 14%, and the 3dB gain bandwidth is greater than 30%.

This invention discloses a high-current, wide-capacitance-range LDO based on a frequency compensation circuit, comprising: a first-stage operational amplifier for amplifying an error signal; a second-stage operational amplifier for further amplifying the amplified error signal; a driving circuit for enhancing the driving capability of the secondary amplified error signal; a current output circuit for adjusting the required output current based on the enhanced driving capability of the secondary amplified error signal and the input voltage; a feedback circuit for generating a new feedback voltage based on the output current; the first-stage operational amplifier also amplifies the new error signal; and a frequency compensation circuit that utilizes a multi-zero-pole dynamic compensation branch and a current buffer supplementary branch to adjust the positions of multiple zeros and poles in the new error signal based on the output current to cancel out secondary poles while widening the entire unity-gain bandwidth, thereby obtaining the adjusted error signal. This invention can still achieve a large bandwidth under a large current output range and a large load capacitance range.

The utility model relates to the technical field of wireless communication, and discloses a novel wide-frequency-band ceramic antenna. The novel wide-frequency-band ceramic antenna comprises a first ceramic antenna, a second ceramic antenna and a third ceramic antenna which are stacked together from top to bottom and have the same size, the first ceramic antenna and the third ceramic antenna are provided with transmitting and receiving end electrodes and feed electrodes; the first ceramic antenna, the second ceramic antenna and the third ceramic antenna are provided with transverse electrodes and longitudinal electrodes, and the transverse electrodes and the longitudinal electrodes are provided with metal through holes. The first, second and third ceramic antennas are stacked to reduce the antenna volume and reduce the installation difficulty; the first ceramic antenna and the third ceramic antenna are respectively provided with a transmitting and receiving end receiving electrode and a feed electrode, and a plurality of transmitting and receiving end electrodes and feed electrodes are arranged, so that the antenna bandwidth is effectively enhanced, and the radio frequency performance and the frequency band coverage range are enhanced. The metal through holes are additionally formed in the antenna electrode, distributed inductance is increased, the standing wave bandwidth and the gain bandwidth of the antenna are enhanced, and the frequency band coverage range of the antenna is increased. The utility model further discloses a wireless temperature and humidity sensor.

The invention provides an optical grating external cavity spectrum beam combining semiconductor laser device for broadening gain bandwidth in airspace, which comprises a spatial gain bandwidth splicing device, the spatial gain bandwidth splicing device comprises a plurality of laser output modules and a plurality of first reflection assemblies, and after light beams emitted by the laser output modules are reflected by the corresponding first reflection assemblies, the light beams are transmitted to the optical grating external cavity spectrum beam combining semiconductor laser device. A light beam array which is emitted in parallel is formed; the multi-wavelength synchronous locking outer cavity device is used for carrying out spectrum beam combination on the light beam array output by the space gain bandwidth splicing device and outputting the light beam array; the plurality of laser output modules have a plurality of different wavelengths, and the plurality of laser output modules are linearly arranged side by side according to a preset wavelength sequence. According to the grating external cavity spectrum beam combining semiconductor laser device with the gain bandwidth broadened in the airspace, the technical problems that the gain spectrum width which can be realized by a semiconductor laser in the related technology is generally narrow, and application requirements of broadband output or large-range tuning and the like are difficult to meet are solved.

The application discloses a wideband low-power consumption transconductance operational amplifier with enhanced slew rate, which comprises an improved cyclic folded transconductance operational amplifier and a slew rate enhancement circuit. The slew rate enhancement circuit can significantly improve the positive and negative slew rates during large signal operation of the amplifier. During small signal operation of the amplifier, the transistors thereof work in a subthreshold region and hardly consume current, so that the unit gain bandwidth and the slew rate of the amplifier can be improved while keeping low power consumption, thereby improving the working speed and output current capacity of the operational amplifier. The embodiment of the application improves the working speed of a high-performance switched capacitor circuit, reduces power consumption, is easy to popularize and use, and can be widely applied to the technical field of operational amplifiers.

This invention discloses a miniaturized beam-scanning (FP) resonant cavity antenna with broadband gain improvement characteristics, comprising a PRS layer, a feed, a vertical metal ground, and a horizontal reflector placed below and parallel to the PRS layer. The feed is a monopole antenna positioned below the PRS layer. The upper edge of the vertical metal ground coincides with one edge of the lower surface of the PRS layer, and the lower edge of the vertical metal ground coincides with one edge of the horizontal reflector. The PRS layer and the horizontal reflector form a resonant cavity, one side of which is covered by the vertical metal ground. The feed is positioned in the center of the vertical metal ground, which serves as the ground plane for the feed antenna. This antenna extends the impedance bandwidth and improves the gain of the feed antenna over a wide range, exhibiting a wide 3dB gain bandwidth and gain improvement bandwidth. Simultaneously, the antenna maintains a small size and has a frequency scanning capability of approximately 0–37°, greatly expanding its application scenarios.

Technologies for a photon pair source integrated on a photonic die are disclosed. In an illustrative embodiment, a photonic die includes an integrated semiconductor laser. The integrated semiconductor laser pumps a Raman laser on the same die. The Raman laser has much lower noise near the laser peak compared to the semiconductor laser, due to a smaller gain bandwidth and less amplified stimulated emission. Due to the low noise, the Raman laser can be used to pump a spontaneous four-wave mixing (SFWM) source directly, without off-chip filtering required. The SFWM source can generate entangled photons with a high signal-to-noise ratio, with applications for quantum cryptography, quantum computing, and other quantum information processing tasks.

The application discloses a gyrotron traveling wave tube axial gradually changing loading high-frequency injection wave interaction circuit structure, relates to vacuum electron technology, and comprises a loading section heat dissipation metal cylinder, a first hollow cylindrical surface and a second hollow cylindrical surface which are coaxial, the radius of the first hollow cylindrical surface is greater than that of the second hollow cylindrical surface, a second substructure as a metal cylinder high-frequency interaction section, gradually changing attenuation ceramic sections arranged at both ends of the hollow cylindrical surface of the first substructure, and the thickness of the gradually changing attenuation ceramic of each section of the gradually changing attenuation ceramic sections of the two parts gradually increases in the axial direction towards the middle part of the first substructure, uniform attenuation ceramic arranged between the gradually changing attenuation ceramic sections of the two parts, and an electron beam channel with a coaxial fixed radius formed based on the hollow cylindrical surfaces of the first substructure and the second substructure. The structure combining axial attenuation at both ends and uniform attenuation can realize precisely controllable attenuation, and can greatly improve the gain, bandwidth and working stability of the gyrotron traveling wave tube.

Some embodiments of the present application show an intelligent device and a spatial sound field calibration method, the method comprising: in response to a user input instruction to start spatial sound field calibration, controlling the loudspeaker to play a preset standard sound at a first sound intensity; receiving a first audio file; calculating a first energy value of a preset frequency point based on the first audio file, and determining a first number of target size audio data in the first audio file; determining a first sound gain of the preset frequency point according to the first energy value, the first number, a preset target gain, a bandwidth and a manual adjustment offset; and calibrating a frequency response curve corresponding to the first sound intensity based on the first sound gain. The embodiments of the present application adjust the sound of the intelligent device according to the room acoustic correction algorithm by collecting the sound attenuated by the room, so that the user can enjoy better sound effect in any differently decorated room and improve the user experience.

The application discloses an arbitrary dielectric constant end-fire leaky-wave antenna based on subarray alternation, which comprises an upper metal, a dielectric substrate and a lower metal arranged in sequence from top to bottom; the upper metal comprises a first metal wire and a first subarray alternately arranged on both sides of the first metal wire; the lower metal comprises a second metal wire and a second subarray alternately arranged on both sides of the second metal wire; the first subarray and the second subarray are symmetric to the axis of the first metal wire and the second metal wire; and the subarrays of the first subarray and the second subarray contain the same number of one or more radiation units. The antenna can generate a stable end-fire radiation pattern through space-1 harmonic radiation, can realize the end-fire leaky-wave antenna on a lower dielectric constant dielectric substrate, can reduce the processing difficulty, and can realize a higher gain length ratio and a larger gain bandwidth.

The invention designs a patch stacked substrate integrated waveguide filtering antenna by utilizing a substrate integrated waveguide structure. The antenna is characterized by comprising a dielectric substrate, an SIW resonant cavity, a ground plane, a radiation patch, a parasitic patch and a lens, the feed structure microstrip line is attached to the bottom of the lowermost dielectric substrate; the SIW resonant cavity and the microstrip line transition adopt a coplanar waveguide structure; the metal ground plane is located on the upper layer of the resonant cavity, and a rectangular groove is etched in the center; and the patch is positioned on the second layer of dielectric substrate and consists of a central square radiation patch and parasitic patches at four corners. According to the antenna, on the basis of an SIW resonant cavity, a rectangular radiation patch is used to generate a high-frequency radiation zero point; the four parasitic patches are loaded, low-frequency radiation zero points are generated at the same time, and the filtering effect is improved. And finally, the position of the parasitic patch is adjusted, a lens is added, two gain bandwidths are combined, and the inhibition depth of the antenna is reduced to be below 20dB. The antenna works in a V wave band and has an application prospect in the field of satellite communication.

A computer-implemented method is provided for generating device parameters of circuits using a pretrained reinforcement learning (RL) agent composed of a graph neural network (GNN) and a fully connected neural network (FCNN). The method is performed by steps including acquiring inputs with respect to a set of desired specifications or one desired specification of a circuit, device parameters, a fixed topology of the circuit and providing the inputs to the RL agent. The desired circuit description includes a graph modeling the topology of the circuit and device parameters of the circuit, and the desired specifications include gain, bandwidth, phase margin, power consumption, output power and power efficiency. The pretrained RL agent performs steps including transmitting an action selected from a set of actions to an environment module, updating the device parameters of the circuit according to the selected action using a data processor of the environment module, obtaining a current specification of the circuit by simulating a netlist of the circuit, acquiring a reward from the environment module, and generating the updated device parameters of the circuit.

The invention discloses an ultra-wide-spectrum multi-core optical fiber for hybrid pumping, a preparation method and an optical fiber amplifier, and belongs to the technical field of optical fibers, the ultra-wide-spectrum multi-core optical fiber comprises an inner cladding layer and an outer cladding layer wrapping the periphery of the inner cladding layer, a plurality of fiber cores are arranged in the middle of the inner cladding layer at intervals, and the periphery of each fiber core is wrapped with a sunken layer; the mixed pumping optimized ultra-wide spectrum multi-core optical fiber is finally obtained by optimally designing the types of doped substances in a fiber core and carrying out gradient design on the molar concentration of the rare earth doped substances in the radial direction of the fiber core. According to the ultra-wide-spectrum multi-core optical fiber, based on unique rare earth ion doping combination, a synergistic effect mechanism among various elements and concentration gradient design of the elements are utilized, gain spectrum coverage and quenching effects are accurately balanced, quenching is inhibited while the gain bandwidth is effectively expanded, and the stability of the amplification performance of the optical fiber is improved; the method provides support and conditions for the design of an ultra-wideband optical communication system, and has an excellent application prospect.

The application relates to the technical field of wireless communication, and discloses a novel wide-band ceramic antenna. The novel wide-band ceramic antenna comprises first, second and third ceramic antennas of the same size stacked together from top to bottom; the first and third ceramic antennas are provided with transmitting / receiving end electrodes and feeding electrodes; the first, second and third ceramic antennas are provided with transverse electrodes and longitudinal electrodes, and the transverse electrodes and the longitudinal electrodes are provided with metal through holes. The first, second and third ceramic antennas are stacked to reduce the antenna volume and the installation difficulty; the first and third ceramic antennas are respectively provided with transmitting / receiving end electrodes and feeding electrodes, a plurality of transmitting / receiving end electrodes and feeding electrodes are arranged, the antenna bandwidth is effectively enhanced, and the radio frequency performance and the frequency band coverage range are enhanced. The metal through holes are arranged on the antenna electrodes, the distributed inductance is increased, the antenna standing wave bandwidth and the gain bandwidth are strengthened, and the increase of the antenna frequency band coverage range is realized. The application further discloses a wireless temperature and humidity sensor.

The application discloses a kind of wideband high gain transmission array antennas based on single-layer dielectric substrate unit, including corner horn antenna and transmission array, and the transmission array includes several transmission units, each transmission unit includes dielectric substrate, upper metal patch and lower metal patch, and upper and lower metal patches are respectively etched the upper surface and lower surface of dielectric substrate. Upper and lower metal patches are all fan ring circular ring superposition type structure, and the opening angle of outermost fan ring is controlled to realize its phase control. In addition, by mirror image upper and lower two layers of metal patch, 360 ° phase range can be obtained. Compared with the conventional high gain wideband transmission array antenna, the application uses single-layer dielectric substrate, avoids using metal through hole and metal column, the unit structure is simpler, and the profile height is effectively reduced. Compared with the existing low profile transmission array antenna based on single-layer dielectric substrate unit, the gain bandwidth and aperture efficiency are significantly improved, and the application scenario is more widely.

A laser device and control method provide mode-hopping-free laser wavelength (frequency) tuning over a wide frequency band of the gain bandwidth of the gain medium, and possibly the entire gain bandwidth of the gain medium. In general, the apparatus and method include reverse dispersion to compensate for wavelength dependent group delay and group velocity dispersion within the laser cavity to achieve broadband mode hopping free wavelength tuning.

The invention relates to a millimeter wave broadband circularly polarized patch antenna which comprises an excitation port, a micro-strip feeder line, a first dielectric plate, a metal floor, a cross-shaped groove, a second dielectric plate and a radiation patch. The microstrip feeder is printed on the lower surface of the first dielectric plate, the metal floor is printed on the upper surface of the first dielectric plate, the cross-shaped groove is etched in the center of the metal floor in a 45-degree inclined mode, the second dielectric plate is stacked on the first dielectric plate, and the radiation patch is printed on the upper surface of the second dielectric plate. The radiation patch comprises four overlapped elliptical patches with the same size, the elliptical patches are connected end to end to form a circular ring, the centers of the four patches are located on the diagonal lines of the second dielectric plate respectively, the distance between the center of each patch and the center of the second dielectric plate is equal, and every two spaced patches are in central symmetry. According to the invention, the non-completely symmetrical elliptical patches are overlapped, so that the resonance characteristics of the microstrip feed, the coupling gap and the radiation patch are mutually overlapped, a multi-resonance mode is formed, and the impedance bandwidth and the gain bandwidth are greatly expanded.

The application discloses a preparation method of a near-infrared vertical cavity surface laser with low threshold and high gain based on weakly confined quantum dots, and belongs to the technical field of quantum dot lasers. A CdS shell layer is grown on the weakly confined double-tapered CdSe quantum dots, and the thickness of the CdS shell layer is controlled to be 2 layers by controlling the injection amount of dodecanethiol; the CdSe / CdS quantum dots are spin-coated on the high-reflection surface of two Bragg reflectors (DBRs); and the surfaces coated with the quantum dots are close to each other and are spliced to form a vertical cavity surface laser. The vertical cavity surface laser constructed by taking the weakly confined double-tapered hexahedral CdSe / CdS quantum dots as deep red gain material has deep red / near-infrared laser emission of 720 nm, an extremely low laser threshold of 11.23 µJ / cm 2 and an extremely wide gain bandwidth of 670-730 nm.