Showing papers on "Radiation mode published in 2018"

Dispersion characteristics of dielectric tube waveguide loaded with plasma for leaky wave antenna application

Abstract: The leaky mode dispersion characteristics ( ω - β ) of a Dielectric Tube Waveguide Loaded with Plasma (DTWLP) is analytically solved and numerically computed using Muller’s complex root search algorithm with an aim to define its complex propagation constant behaviour. Consequently, complex leaky mode characteristics and its classification as guided mode, reactive mode and antenna mode have been investigated. These modal characteristics reveal wide fundamental antenna mode (TM01) with the variation in plasma density, which can find prospective application in high resolution radar and communication system where “re-tuning” of the antenna to a new frequency or making it electrically invisible is required. A computational cum simulation study is also performed using CST Microwave Studio software, which confirms our analytical findings.

Radio-over-fibre beamforming device based on array waveguide grating (AWG) and method thereof

Abstract: The invention relates to a radio-over-fibre beamforming device based on an array waveguide grating (AWG) and a method thereof. Radio-frequency signals are modulated onto carriers of multiple wavelengths, and processed by a programmable optical true time delay module in an optical domain; the module is composed of an optical switch and multiple cascade AWGs capable of providing different basic delays between adjacent wavelength channels; the basic delay amounts of different-level AWGs are in geometric distribution by taking 2 as the common ratio; optical carriers different in wavelength enter different branches to perform photoelectric conversion, so that radio-frequency signals different in delay (phase) are recovered; and thus, a far-field beam directional radiation mode is realized. Theradio-over-fibre beamforming device based on the AWG and the method thereof disclosed by the invention have the characteristics of being wide in band, adjustable, flexible, small in volume, easy to integrate and the like, and are very importantly applied in dynamic scenes, such as next generation mobile communication and high-speed railways.

Multi-mode paster broadband antenna and design method therefor

Abstract: The invention discloses a multi-mode paster broadband antenna and a design method therefor. The antenna consists of a fan-shaped paster radiation unit, a reflection board, a feed port, and transmission line branch nodes. The paster radiation unit is a fan-shaped paster unit which has a certain angle range, and a pair of terminal open-circuit or short-circuit transmission line branch nodes are introduced to the interior or edge of the paster radiation unit, so as to disturb a high-order resonant radiation mode of the fan-shaped paster unit and enable the high-order resonant radiation mode to work with a low-order radiation mode, thereby achieving the broadband working characteristics. The combined antenna can be used independently, and also can be integrated with a parasitic unit for combined use. The combined antenna can achieve the broadband working characteristics in various modes of the paster antenna, is simple in structure, and is low in cost. The technology is easy to implement,so a design method can be widely used in many fields.

Design of Wide-Band 2-D Holographic Antenna Using Wedge Reflector

Abstract: In this paper, the effect of forward and backward radiation modes in 2-D holographic leaky wave antennas are described. The suppression of backward radiation mode is proposed to prevent the destructive effect of the excitation of the forward and backward radiation modes at frequencies that are lower than the designed operating frequency. Wedge reflector is placed next to the launcher in order to improve the radiation characteristics of the antenna. The presence of the wedge reflector changes the distribution form of the reference wave. The antenna is designed to operate over 13–18 GHz frequency band and a bandwidth of 32% is obtained.

Inclined fiber grating surface super-structure enhanced surface plasmon resonance hydrogen-sensitive sensor

Abstract: The invention discloses an inclined fiber grating surface super-structure enhanced surface plasmon resonance hydrogen-sensitive sensor. The inclined fiber grating surface super-structure enhanced surface plasmon resonance hydrogen-sensitive sensor is composed of an ASE broadband light source, a polarization controller, a single-mode optical fiber, a gas chamber base, an air inlet, an air outlet, aPd/Au thin film optical fiber hydrogen sensor, a spectrum analyzer and a gas chamber barrier; the surface of the Pd/Au thin film optical fiber hydrogen sensor is coated with an Au nano film and a Pdnano film, and an inclined Bragg grating is engraved on a fiber core. Au and Pd nano particles are prepared by using a chemical liquid phase reduction method. The controllable growth of Au and Pd nanofilms on a quartz substrate is achieved by using a molecular self-assembly (SAMS) technology and a chemical coating method. The inclined Bragg grating within the films allows light to be coupled fromthe fiber core to a large number of higher-order modes guided by a fiber cladding, so that the coupling of a radiation mode is enhanced. Within the 1.5% to 4% hydrogen concentration range, the sensorhas good linear response characteristics, and once the hydrogen concentration changes by 1%, the spectral amplitude vibration is 0.005dB, and the sensor has better sensitivity and resolution.

Method for reducing femtosecond laser direct write waveguide bending loss

Abstract: The invention provides a method for reducing femtosecond laser direct write waveguide bending loss. The core of the method comprises two schemes: 1, laser direct writing and auxiliary chemical etchingare performed on the external side of the bending waveguide so as to obtain an air slot through etching; and 2, laser direct writing of multiple layers of damage lines producing stress is performed on the two sides of the bending waveguide. The effective refractive index of the bending waveguide can be increased so that the radiation mode of the waveguide can be reduced, the bending loss can be greatly reduced, the bending radius of the bending waveguide in the device can be effectively reduced, the structure of the waveguide device is enabled to be more compact, and the method has importantmeaning for the field of integration, chip development and optical interconnection of the three-dimensional optical device in the micro-nano optics.

Analytic Study on the Small Antennas Coupling for Wireless Biotelemetry

Abstract: We derive closed form expressions of the power transfer efficiency between the transmitting antenna inside the brain and the receiving antenna outside the human head using spherical wave theory for small antennas. The radiation mode and the properties of the biocompatible insulator layer are analyzed at each available wireless biotelemetry frequency band for high power transfer efficiency. It is found that the PTE values are dependent on the antenna radiation mode and the insulator thickness. This work can be used for guiding the antenna design for building reliable wireless link for the biotelemetry system.

Multi-band MIMO terminal antenna based on ground radiation mode

Abstract: The invention discloses a multi-band MIMO terminal antenna based on a ground radiation mode The antenna comprises a dielectric substrate, a metal ground and a plurality of antenna units; the plurality of antenna units are arranged on the edge of the dielectric substrate, and the metal ground is paved on other positions; the adjacent antenna units are arranged in a mirror symmetry mode, and the antennas is fed by a coaxial feeder line; each antenna unit comprises a first radiation metal strip and a second radiation metal strip, wherein the first radiation metal strip and the second radiation metal strip extend from a feed opening; the second radiation metal strip is embedded in the first radiation metal strip; and the radiation branch root parts of the first and the second radiation metalstrips are connected with the metal ground through capacitors C1 and C2 By virtue of the nesting structure of the metal strips, the multi-band mode of the ground antenna is achieved, and the space utilization rate of the antenna is improved; and meanwhile, the capacitors are connected in parallel between the multi-layer nesting structure and the metal ground, so that the electric length of the antenna is prolonged, and the physical size of the antenna is reduced

Ellipse leakage soft waveguide with dual-polarization radiation mode

Abstract: The invention discloses an ellipse leakage soft waveguide with a dual-polarization radiation mode. The ellipse leakage soft waveguide comprises two ellipse metal waveguide tubes, wherein the two ellipse metal waveguide tubes are arranged in parallel and are formed by embossing, outer sheaths are arranged outside the two ellipse metal waveguide tubes and are connected via a connection rib, a vertical polarization leakage unit of a radiation vertical polarization wave and a horizontal polarization leakage unit of a radiation horizontal polarization wave are respectively arranged on end surfacesof the same sides of the two ellipse metal waveguide tubes, and the field intensity between the vertical polarization leakage unit of the radiation vertical polarization wave and the horizontal polarization leakage unit of the radiation horizontal polarization wave is 20dB or above. By the leakage soft waveguide, multiple input and multiple output of rail traffic vehicle-ground wireless signal transmission are achieved, isolation degree among different signals is improved, high-capacity and high-quality transmission of the signals in different channels is ensured, interconnection and mutual communication of a multi-communication system such as LTE-based vehicle-ground wireless transmission integrally-borne communication based train control system (CBTC), PIS, Wi-Fi and LTE-E is achieved, and the ellipse leakage soft waveguide is adapted to 5G development and application demands.

A Novel Broadband Microstrip Patch Antenna with Small Ground Plane

Abstract: A novel broadband microstrip patch antenna with a small ground plane is proposed in this paper. An additional ground radiation mode with low-frequency resonance is introduced by the small ground plane, while the patch radiation mode resonates at high frequency. The radiation patch is loaded with a pair of slots and two rows of shorting pins to obtain broadband matching. A relative bandwidth of 58.8%, from 2.11GHz-3.87GHz, is achieved for a compact size of 0.41λ 0 *0.29λ 0 *0.03λ 0 at center operating frequency. In addition, omnidirectional radiation patterns with low cross-polarization are achieved over the operating band.

Optical transmission path

Abstract: PROBLEM TO BE SOLVED: To make it possible to reduce power density of light in an end face of an optical transmission path, thus suppressing deterioration of end faces of an optical waveguide and an optical fiber, in using the light (or laser beam) ranging from a visible region (wavelength of 450 nm or less) to an ultraviolet region in wavelengthSOLUTION: An optical transmission path comprises a cladding layer and a core formed inside the cladding layer A buffer layer is formed in an end face of the core, and light emitted from the core propagates in a radiation mode in the buffer layerSELECTED DRAWING: Figure 4

Back-To-Back Magnetic Dipole Antennas with Pattern Reconfigurability

Abstract: A pattern reconfigurable antenna capable of steering in the wide angle is presented in this paper. The proposed antenna is composed of back-to-back magnetic dipole (MD)antennas. Each antenna can be a driven element or a parasitic structure by switching the radiation mode. The 3-dB beam under varying four radiation modes can cover ± 72° in elevation angle. The spacing between two antennas is 0.23 wavelength (λo)to utilize as an array antenna, and the size of the antenna is 0.38λo X 0.38λo.

Holograms Form Factor and the Recording Laser Radiation Mode Structure

Abstract: The lasers application in the information systems have to be preceded by the development of the requirements to the laser radiation parameters. It is clear, that the lasers radiation coherence growth by means of which the holograms were registered leads the holograms quality improvement.

Method for determining dominant sound radiation mode of coupling closed acoustic cavity

Abstract: The invention relates to a method for determining the dominant sound radiation mode of a coupling closed acoustic cavity. The method includes the steps of calculating and comparing the radiation efficiency coefficient lambda m of each order of sound radiation modes of the coupling closed acoustic cavity, and primarily selecting possible dominant sound radiation modes; fully considering the actionof the mode amplitude, amplifying the primary selection order so as to reserve a margin; arranging a sensor array on a structural vibration surface to measure the vibration speed data, obtaining the possible dominant sound radiation modal amplitude yi of the front J orders; calculating and comparing the sound potential energy which contributes by the possible dominant sound radiation modes of thefront J orders, and finally determining the dominant sound radiation mode. According to the method, two factors including the radiation efficiency and the modal amplitude are comprehensively considered, the dominant sound radiation modal can be accurately identified, and the modal order truncation is realized through the " primary selection " link. The workload is greatly reduced, the structure modal information of a radiator does not need to be used in a determination process, and engineering implementation is facilitated.

Woody pellet combustion device

Abstract: PROBLEM TO BE SOLVED: To preferably switch operation mode to warm air mode or radiation mode.SOLUTION: In a pellet stove 10, when operation mode is switched to warm air mode, a warm motor is driven, a warm fan 76 is rotated and heated air is blown from an air outlet 74 into a room. When operation mode is switched to radiation mode, the warm motor is not driven, the warm fan 76 is not rotated and heated air is discharged into the room from a slit 70 with natural convection.SELECTED DRAWING: Figure 2