233 results about "Gain bandwidth" patented technology

The invention provides a phase delay linetype reflector element based reflective array antenna. The reflective array antenna comprises a pyramid horn feed source and a reflector array, wherein the reflector array is formed by periodically arranging a plurality of phase delay linetype reflector elements in a mirror symmetry manner; and the phase delay linetype reflector element structure comprises two slotting circular ring nests and two phase delay lines that are in opposite in positions. The gain bandwidth of the reflector array antenna is greatly increased, an ultra wide band antenna is realized, and cross polarization is effectively restrained as well; and in addition, the reflection array antenna provided by the invention adopts a single-layer dielectric substrate structure, so that the reflector array is simple in structure, easy to process, low in cost and light in weight.

The invention discloses a broadband foldable reflective array antenna, and belongs to the technical field of antennas. The broadband foldable reflective array antenna employs a foldable reflective array antenna structure, and provides a brand new reflective array unit, so that the foldable reflective array of the reflective array unit solves the problem that breakthrough on gain bandwidth of a conventional foldable reflective array antenna is hard to achieve. The characteristics of high gain, low loss, compact structure and low cross polarization of a foldable reflective array antenna are fully explored. The broadband foldable reflective array antenna is suitable for microwave, millimeter wave, THz frequency ranges and applicable to high performance communication or radar systems.

The invention discloses a novel broadband low-profile dielectric lens antenna, and belongs to the technical field of microwave. The antenna feed source part of the lens antenna comprises two layers of dielectric plates; rectangular gaps in the metal grounding surface of the bottom layer dielectric plate of the feed source are coupled with square patches on the upper layer dialectic plate through an air layer to generate polarized wave; a novel cavity-free part reflective surface consists of two layers of frequency selection surfaces with dielectrics, and the reflective phases are changed along with frequencies in a positive slope manner and are matched with the feed source antenna so as to greatly improve the 3dB gain bandwidth of the antenna finally; by virtue of the cavity-free part reflective surface, the profile height of the resonant cavity antenna is lowered, so that the low profile characteristic of the antenna is realized; in addition, the reflective coefficient of the novel part reflective surface is higher than that of the similar type surface, so that the working frequency band gain of the antenna is improved stably; and in general, the design has certain application prospect.

The present invention relates to a fiber having a core of crystal fiber doped with chromium and a glass cladding. The fiber has a gain bandwidth of more than 300 nm including 1.3 mm to 1.6 mm in optical communication, and can be used as light source, optical amplifier and tunable laser when being applied for optical fiber communication. The present invention also relates to a method of making the fiber. First, a chromium doped crystal fiber is grown by laser-heated pedestal growth (LHPG). Then, the crystal fiber is cladded with a glass cladding by codrawing laser-heated pedestal growth (CDLHPG). Because it is a high temperature manufacture process, the cladding manufactured by this method is denser than that by evaporation technique, and can endure relative high damage threshold power for the pumping light.

The present invention relates to Erbium Ytterbium codoped multi-component oxide glass monomode fiber core glass and a method for preparing monomode fiber. The core glass comprises SiO2, Al2O3, Li2O, Yb2O3, Er2O3, B2O3, etc. A round bar is made from Erbium-doped glass blank, a core glass is formed by drawing it into a thin round bar; another round bar is made from non-Erbium-doped glass blank, a cladding glass is formed by laser punching it; the thin round bar is placed in the hole of the cladding glass to form an Erbium-doped optical fiber performrod; then a monomode fiber is obtained by drawing the performrod in a wire drawing furnace. The invention solves the problems in the prior art of uneven gain spectrum, narrow gain bandwidth, complicated preparing technology and so on. The Erbium Ytterbium codoped multi-component oxide optical glass fiber can provide transmission bandwidth of 60nm and more even gain spectrum, higher glass transition temperature, better chemical and heat stability, can satisfy the increased requirements of the current optical transmission network.

An electronic amplifier circuit comprising an operational amplifier circuit, such as a two-stage operational amplifier circuit, in tandem with a operational transconductance amplifier. The electronic amplifier circuit has high open-loop gain and high gain-bandwidth while maintaining stability over a wide range of operating parameters.

The invention discloses a tunable ytterbium-doping double-clad fiber mode-locked laser which belongs to the technical field of lasers. The tunable ytterbium-doping double-clad fiber mode-locked laser is in an annular cavity structure, takes a large-core diameter double-clad ytterbium-doping fiber as a gain medium and works on a total positive dispersion area. The tunable ytterbium-doping double-clad fiber mode-locked laser realizes the mode locking self-starting and stably carries out mode locking by dint of a nonlinear polarization rotation technology and a spectrum filter, is adjustable in filtering bandwidth because the spectrum filter comprises a grating and a slit with adjustable width, has a tuning function and can continuously tune the center wavelength of an output pulse within a gain bandwidth range. The tunable ytterbium-doping double-clad fiber mode-locked laser disclosed by the invention realizes the total positive dispersion mode locking of the large-core diameter double-clad fiber by adopting nonlinear polarization rotation and a spectrum filter technology, obtains the ultrashort-pulse laser output supporting high power and high single-pulse energy, is continuously tunable in center wavelength and is convenient to operate and large in tuning range by composing the spectrum filter by adopting the grating and the slit.

Dual amplifying circuits having a magnetic tunnel junction device and a field effect transistor configured in a complementing set are disclosed herein. In one embodiment, the field effect transistor is operable to control a current level of a current operating signal flowing through the magnetic tunnel junction device. In another embodiment, the magnetic tunnel junction device is operable to control a voltage level of a voltage signal being applied to a gate terminal of the field effect transistor. The gain-bandwidth product of both embodiments is greater than the individual gain-bandwidth products of the individual devices through the elimination of noise contributing resistive type circuit elements.

The invention relates to the technical field of laser, and provides a broadband optical parameter chirped pulse amplifier. The broadband optical parameter chirped pulse amplifier comprises a narrow-band picoseconds laser device, a pulse laser stretcher, an optical coupling mirror, a beam expanding / contracting system, periodic poling crystal, a spectroscope and a pulse laser compressor. The periodic poling crystal with the periodic domain inversion structure is used for separating generated idler frequency light from chirped pulse laser / pumping light to inhibit energy backflow after the broadband optical parameter chirped pulse amplifier is in a saturated amplification state, and therefore broad optical parameter chirped pulse amplification of a broadband is achieved. The broadband optical parameter chirped pulse amplifier is capable of inhibiting backflow of signal light energy and has extremely wide gain bandwidth, benefited from synchronous optimization of pulse energy (conversion efficiency) and pulse width (gain bandwidth), outputable peak-peak power of the broadband optical parameter chirped pulse amplifier is greatly promoted, and performance of the broadband optical parameter chirped pulse amplifier is improved.

The invention discloses a broadband low-loss passive balun on chip having a laminated winding structure. The balun on chip is provided with three layers of metal conducting wires. The metal conducting wires in a first layer are secondary conducting wires, the metal conducting wires in a second layer are primary conducting wires and the metal conducting wires in a third layer are ground wires. U-shaped continuous bent winding structures are formed between the heads and tails of the conducting wires of each layer. The geometrical shapes of all U-shaped bends are completely consistent. The U-shaped bends are broken from midpoints between the heads and tails of the secondary conducting wires in the first layer to form left and right discontinuous U-shaped bend sections. Single-end signals of an unbalanced end are connected with the heads of the primary conducting wires. The tails of the primary conducting wires are connected to the ground wires. The heads and tails of the secondary conducting wires are all connected with the ground wires. Breakpoints of the conducting wires in the same sections with the heads of the secondary conducting wires are normal phase signal output ends, and the breakpoints of the conducting wires in the same sections with the tails of the secondary conducting wires are inverted signal output ends. The single-end signals of the unbalanced end are convertedinto differential signals of a balanced end for output under the coupling action of the primary and secondary conducting wires. The ground wires reduce the insertion loss of the balun and simultaneously expand a gain bandwidth and a matched bandwidth.

Methods and apparatus for regulating a synchronous rectifier DC-to-DC converter by adjusting one or more existing synchronous rectifiers in the converter are provided. By regulating an existing synchronous rectifier, the rectifier may function as a modulator for post regulation over a limited range of output voltages suitable for load regulation, without introducing an additional conversion stage for post regulation, which typically decreases efficiency and power density. Independent post regulation of an existing synchronous rectifier may improve the load regulation, reduce output voltage ripple, and improve the transient response of the converter. By operating independently from the main control loop, post regulation may most likely avoid the limitations of the main control loop, such as limited gain bandwidth and a relatively slow transient response. Such post regulation may be added to isolated or non-isolated switched-mode power supplies, such as forward or buck converters.

The invention discloses a broadband string series-feed circular polarization patch antenna. The broadband string series-feed circular polarization patch antenna is provided with a rectangular radiation medium substrate, wherein the rectangular radiation medium substrate comprises a small square radiation metal patch on an upper surface and a large square radiation metal patch on a lower surface, the upper and lower surface of the rectangular radiation medium substrate are respectively printed with a rectangular sheet metal and a series-feed microstrip line, a tail end of the series-feed microstrip line is connected with the rectangular sheet metal through a load resistor, and the rectangular sheet metal is provided with N sets of rectangular metal slits through etching. The broadband string series-feed circular polarization patch antenna is advantaged in that a serial traveling wave feed structure integrating the series-feed microstrip line and the load resistor is employed, an antenna feed network is simplified, and the antenna is convenient for making and processing; the two radiation metal patches with different sizes are employed to widen radiation gain bandwidth of the antenna; the two rectangular metal slits of which directions are perpendicular mutually are arranged below the large square radiation metal patch, phase difference of the two rectangular metal slits is 90 DEG, an antenna array element axial ratio is made to be a relatively small value, and thereby an antenna axial ratio bandwidth is substantially improved.