130 results about "Circular symmetry" patented technology

The invention belongs to the field of laser processing, in particular to a multi-beam center wire feeding laser processing head and a processing method of the multi-beam center wire feeding laser processing head. The laser processing head comprises a wire feeding tube, a wire feeding nozzle and a plurality of identical optical modules, wherein the wire feeding tube and the wire feeding nozzle are located on the center axis of the laser processing head, the optical modules are rotationally and symmetrically distributed around the center axis, each optical module comprises a collimating lens set, a focusing lens set and a reflecting mirror set, lasers are transmitted to the processing head through a plurality of paths of optical fibers, a plurality of laser beams are focused on one point of the surface of a workpiece to form a molten pool after being collimated, focused and reflected by the optical modules, a metal wire is perpendicularly fed into the molten pool on the surface of the workpiece through the fire feeding nozzle, and the laser processing head moves on the surface of the workpiece according to a certain track so that the center wire feeding laser processing process can be achieved. Through the multi-beam center wire feeding laser processing head, center wire feeding in laser focusing light spots in circular symmetry distribution is achieved, and the processing quality consistency is guaranteed when the laser processing head moves in different directions.

The present invention aims to propose a method to generate a security pattern to be embedded in an original image having the particularity that the detection of the security pattern can be achieved through a simple, low processing capability device. The present invention proposes a method for generating a security image comprising an original image and a security pattern, characterized in that the security pattern has the form of a grating in which the lines width and / or the line spacing is modulated to embody a predefined data, the security image is generated by the modulation of at least one color of at least a part of the original image with the grating. The present invention belongs to the fields of security printing and copy protection of banknotes. It aims at preventing illegal copy and duplication of banknotes by printing a security image on the banknote. A device capable of detecting this security image with one-dimensional signal processing is described. Acquisition and printing devices that contain this detector can perform a quick, on-the-fly analysis of the images that transit through them during their normal course of operations, and refuse to perform their function on an image if it contains the security image. This analysis is fast enough relatively to the normal operation of the device so as to go unnoticed by the user. The security image is incorporated by a bi-level halftone image. The Fourier transform of this halftone image contains a two-dimensional pattern with a circular symmetry that is built by applying a 360-degree rotation to a one-dimensional signal. This one-dimensional signal exhibits a degree of self-similarity across a given range of scale changes. It may be detected by traversing the two-dimensional pattern along a straight line passing through its center.

A coaxial connector junction includes first and second coaxial connectors. The first coaxial connector includes: a first central conductor extension; a first outer conductor extension spaced apart from and circumferentially surrounding the first central conductor extension; and a first dielectric spacer interposed between the first central conductor extension and the first outer conductor extension. The second coaxial connector includes: a second central conductor extension; a second outer conductor extension spaced apart from and circumferentially surrounding the second central conductor extension; and a second dielectric spacer interposed between the second central conductor extension and the second outer conductor extension. Each of the central conductor extensions and the outer conductor extensions has circular symmetry about the longitudinal axis, such that electrical properties of the engaged first and second coaxial connectors are substantially the same irrespective of the relative orientations of the first and second coaxial connectors about the longitudinal axis.

A method of using an image capture device to identify range information for objects in a scene includes providing an image capture device having an image sensor, a coded aperture having circular symmetry, and a lens; storing in a memory a set of blur parameters derived from range calibration data; capturing images of the scene having a plurality of objects; producing a set of reference edge images using the blur parameters from the stored set; providing a set of deblurred images using the captured image, the reference edges and each of the blur parameters from the stored set; and using the set of deblurred images to determine the range information for the objects in the scene.

The invention discloses a magnetic suspension vertical turbine wind generator. A wind guiding passage of a turbine and an axis line parallel to the wind direction form an included angle of 35 to 40 degrees; an axial bearing structure consists of a main bearing part consisting of a magnetic bearing and an auxiliary bearing part consisting of mechanical rollers; the mechanical rollers are distributed symmetrically and circularly arranged on an object stage of a tower base; the magnetic bearing comprises active suction type electromagnet coils which are vertically arranged above and below a main working shaft cam to correspondingly form a working unit, all working units are equally distributed in circular symmetry and arranged outside the mechanical rollers in concentric circles with mechanical roller bearings, and each electromagnet unit ensures that magnetic poles are opposite; and the turbine is in a form of vertical turbine structure. The wind generator has a reasonable structure, can obtain higher generating efficiency under the condition of low wind speed, and has the advantages of low starting wind speed, high wind energy utilization efficiency, simple structure and convenient maintenance.

The invention discloses a photon lantern type degenerate module multiplexer / demultiplexer and a transmission method. The multiplexer / demultiplexer structure comprises a plurality of fiber cores, wherein the fiber cores for transmitting different LP modes are different in thickness, and degenerate modes in the same mode group adopt the same fiber core; the fiber core arrangement cross section is axisymmetric, the fiber cores in the excitation circular symmetry mode are arranged on the symmetry axis, and the fiber cores in the excitation non-circular symmetry mode are symmetrically arranged on the two sides of the axis; the fiber cores are arranged in concentric rings, and the fiber cores in the excitation LPpq mode are located on a q-th ring from outside to inside, and the fiber cores on the two sides of each ring are sequentially arranged in a thinning mode from the fiber core located on the symmetry axis; and one end of the arranged fiber core forms a conical coupling region of a multiplexer / demultiplexer through fused biconical taper. According to the invention, the degenerate mode group receiving problem is solved, and the degenerate mode group receiving method has the advantages of wide working bandwidth and low crosstalk.

A novel laser cavity structure is disclosed which pertains to laser resonator geometries possessing circular symmetry, such as in the case of disk or spherical lasers. The disclosed invention utilizes a very-high finesse Bragg reflector (VHF-BR) thin film reflectors of many layer pairs of very small refractive index difference, the VHF-BR deposited on a surface of revolution, thereby forming an optical cavity. These dielectric reflectors are disposed in such a way as to allow selection of preferred low order modes and suppression of parasitic modes while allowing a high cavity Q factor for preferred modes. The invention disclosed, in its preferred embodiments, is seen as particularly useful in applications requiring high efficiency in the production and coupling of coherent radiation. This is accomplished in a cavity design that is relatively compact and economical. Of particular novelty is the combination of the disclosed cavity design with polymer multilayers. The ability to deposit an unusually large number of polymer thin films without loss of specularity, while maintaining very low extinction, renders the disclosed polymer-based cavity particularly well-suited for higher mode discrimination, more rugged and light-weight cavities, as well as economical fabrication.

The invention discloses a local ternary pattern texture feature extraction method based on mean sampling. First, the dimension of a local ternary coding sequence of all possible values is reduced preliminarily based on rotation invariance and is further reduced according to the dimension reduction conditions, and a pattern mapping table containing the corresponding relationship between original pattern number and final pattern number is built. Neighborhood circular symmetry average sampling is carried out on each non-edge pixel of a texture image of which the features are to be extracted, effective coding points are acquired from sampling points and coded to get a local ternary coding sequence of the non-edge pixels and corresponding original pattern numbers, corresponding final patterns are looked for in the pattern mapping table, the non-edge pixels covered by each final pattern are counted in the texture image, and a feature vector of the texture image is constructed. According to the invention, the noise is controlled and the accuracy of texture features is improved through mean sampling, and the dimension of the feature vector is controlled effectively through a dimension reduction method.

The invention discloses a multi-pass SAR coherent change detection method based on a general likelihood ratio. The multi-pass SAR coherent change detection method includes the steps that S1, multi-pass SAR image pairs are selected and recorded as {f1, f2,..,fk}; S2, multi-pass SAR image pixel pairs are selected; S3, maximum likelihood estimation is carried out on a covariance matrix; S4, likelihood ratio hypothesis testing is carried out; S5, the multi-pass SAR image pixel pairs are sequentially selected, and the step S4 is repeated to obtain a change detection result. The multi-pass SAR coherent change detection method assumes that complex pixels corresponding to an SAR imaging area changing in the multiple image collecting stage and complex pixels corresponding to the SAR imaging area not changing in the multiple image collecting stage follow different circular symmetry complex Gaussian distributions respectively, the covariance matrix of the circular symmetry complex Gaussian distributions in the assumption is estimated, then detection statistics is determined and compared with a threshold, whether the two assumptions succeed or not is checked, namely whether the imaging area changes or not is detected, the tiny changes can be detected, and the changing process can be observed.

The invention discloses an angular spectrum scanning quasi-confocal annular microstructure measuring device and method of array illumination, and belongs to the field of ultra-precision three-dimensional microstructure surface morphology measurement. The device is designed to be provided with an angular spectrum scanning illumination light path; after sequentially passing through an imaging lens, a beam splitter prism and a microscope objective, beams emitted from a concentric annulus light source are shone onto the surface of a circularly-symmetrical microstructure sample to be measured in parallel, and different annular rings of the concentric annulus light source correspond to different angular spectra for illumination. According to the method, tomographic images of all the pixels under scanning illumination of different angular spectra are acquired first, then, on the basis of the confocal three-dimensional measurement principle, the axial coordinate of each pixel is judged, and finally the three-dimensional morphology of the microstructure sample to be measured is obtained in a fitting mode. Due to the design, an optimum illumination angle can be found for every part of the circularly-symmetrical microstructure sample to be measured, and the device and method avoid the problem that some areas can not be illuminated or complex reflection occurs to the areas, wherein the problem is caused by bumps of the surface profile of the circularly-symmetrical microstructure sample to be measured. Detection signal strength is promoted, background noise is lowered, and measurement precision is improved.

The invention discloses a multifocal light beam generation apparatus and a multifocal confocal scan microscope. The multifocal light beam generation apparatus comprises a light source, a polarizer and a polarization filtering optical path. The polarization filtering optical path is provided with a first polarizing beam splitting mirror at an optical path after light source emission light beams pass through the polarizer, and after the light beams pass through the first polarizing beam splitting mirror, a part of the beams is reflected, and a part of the beams is transmitted; on a reflection optical path, a first reflecting mirror, a first filter plate and a second polarizing beam splitting mirror are arranged in order; on a transmission optical path, a second filter plate, a second reflecting mirror and the second polarizing beam splitting mirror are arranged in order, and a reflection light beam and a transmission light beam are joined at the second polarizing beam splitting mirror to form a light beam. After focusing of the light beams which are generated through the multifocal light beam generation apparatus, an obtained focus has the characteristics of high uniformity, small dimension and circular symmetry distribution of a shape. According to the scan microscope, a fast imaging speed under the premise of a high resolution can be ensured, or a higher resolution is provided with the same imaging speed.

The invention relates to a high-anti-multipath high-precision measuring type antenna and communication equipment. The antenna comprises a central radiation unit assembly, a support assembly, a ground plate assembly, a half-opening round chamber assembly, a polarized isolation power dividing device and a wave-transmitting sealing antenna housing. The central radiation unit assembly is fixed on the top of the support assembly. The support assembly is fixed on the center of the ground plate assembly. The half-opening round chamber assembly is coaxially arranged in a way to abut on the back side of the ground plate assembly. The polarized isolation power dividing device is arranged on the back side central part of the ground plate assembly. The central radiation unit assembly is connected with the polarized isolation power dividing device through a coaxial supply line arranged inside the support assembly. The antenna is fully sealed inside the wave-transmitting sealing antenna housing. The antenna which achieves multi-frequency, broadband and stable radiation phase center characteristics further achieves a full-space single lobe pattern and has the advantages of high circular symmetry, high roll-off, high front-to-back ratio, and good wide angle circular polarization characteristics. Furthermore, the antenna has the characteristics of super strong anti-multipath performance, small size, lightness, high reliability, low cost, etc.

The invention discloses a high-energy laser homogenizing cavity attenuator which comprises a front panel, a small-hole sample plate, an attenuation plate, an output panel and a plurality of scattering attenuation units. Each attenuation unit includes a large-angle sampling taper hole arranged on the small-hole sample plate, a homogenizing cavity and a light transmission channel which are arranged on the attenuation plate, and a homogenizing cavity and a laser output hole which are arranged on the output panel, wherein the light transmission channel is of a circular symmetric structure, which enables the angle characteristic of the attenuator to have circular symmetry. The attenuator has a multi-layer plate structure, which can effectively reduce the influence of high temperature generated due to long-time irradiation of high-energy laser on the front panel to a subsequent measurement unit. According to the attenuator of the invention, laser is output from the output hole after being homogenized for multiple times, substantial attenuation of the laser power density is achieved, and the attenuator has better attenuation angle characteristics.

A solution to the problem of long, e-beam mastering times needed for patterning masters for patterned magnetic disk media is disclosed. A process for fabrication of masters takes advantage of the circular symmetry of magnetic disks and reduces the total required mastering time by an order of magnitude over prior art processes. This process relies on e-beam mastering of one small arcuate portion of the master, and then replicating that portion around a circular path on the master several times to create a full disk master. The architecture of this design also corrects for errors in head positioning on the final patterned media disk that may be introduced by the mastering process.

Internally vented brake disk rotors (1) having the form of a cylindrical slab having annular geometry and having an axis of circular symmetry for its outer circumference and its inner circumference, with a centre hole which is symmetric with regard to the said axis, comprising at least two parallel ring disks (2) which are connected with each other by a repeating series of ribs, the design of which brake disk rotor is symmetric with regard to different sense of rotation of the said brake disk (1), i. e. symmetric to at least one plane spanned by the axis of rotation of the brake disk and one radius of the cylindrical brake disk.

Exemplary embodiments provide optical systems and methods for producing interferometric lithography (IL) patterns with circular symmetry for applications such as memory devices including CD ROMs, DVDs, magnetic hard disk storage, and the like. Specifically, one or more axicon optics can be configured in the optical systems for IL patterning processes to form a uniform set of rings with constant increment in all directions in a developed photoresist. In an exemplary embodiment, the optical system can transform a first portion of a plane wave into a radial symmetric wave with a constant angle of incidence onto a photoresist plane of a wafer. This radial symmetric wave can then interfere with a second portion of the plane wave incident but with a different angle of incidence to produce a periodic spatially-varying intensity pattern with circular symmetry.

The invention provides a self-assembly type super-resolution optical probe based on fiber optical tweezers. The self-assembly type super-resolution optical probe is characterized by being composed ofa multi-core optical fiber double-optical-tweezers system and medium microspheres with two diameters. Specifically, the multi-core optical fiber is provided with a peripheral fiber core and a middle fiber core which are distributed in a circular symmetry mode, and an optical fiber end is provided with a symmetrical cone frustum structure, so that captured light beams transmitted in the peripheralfiber core are focused, and double optical tweezers are formed in the axial direction of the optical fiber and used for capturing the microspheres with two diameters in a cascading mode; the middle fiber core of the multi-core optical fiber transmits short-wavelength nanometer optical jet flow illumination light, light beams are emitted out of the optical fiber end and then irradiated on the microspheres captured in a cascade connection mode, and nanometer-scale-size optical jet flow is generated through two-stage compression of the microspheres. The self-assembly type super-resolution opticalprobe can be used for nanometer resolution optical detection, and can be widely applied to the field of super-resolution fluorescence detection and imaging.

The invention provides an annular optical fiber with an asymmetrical optical grating and application in orbital angular momentum generation thereof. A hollow core annular optical fiber can increase the effective refractive index between degeneracy-similar modes, thereby preventing crosstalk between the modes. A long period optical grating inscribed on the upper half ring of the hollow core annular optical fiber breaks a circular symmetry structure of the optical fiber and achieves conversion between angular non-same order modes. When input light is of a circular polarization fundamental mode, a first-order orbital angular momentum mode can be generated. The hollow core of the hollow core annular optical fiber is filled with an optical functional material with the refractive index adjustable and the wave length for generating the orbital angular momentum mode can be tuned by the refractive index of the liquid, so that the structure can generate the orbital angular momentum mode in an adjustable cross band wave length range. Simulation shows that when the optical grating period is 292 [mu]m and the optical grating length is 1.460cm, the range of broad band wave lengths with the angular momentum mode conversion rate higher than 90% can reach 237nm, the greatest conversion rate is 98.91%, and the modulation rate of the refractive index of the filling liquid for the wave lengths for orbital angular momentum mode generation is 400nm / RIU.

The hydraulic antivibration support comprises two strength members interconnected by an elastomer body defining part of a liquid-filled working chamber which communicates via a constricted passage with a compensation chamber that is separated from said working chamber by a rigid partition. The compensation chamber is defined by an annular bellows presenting an annular fold which projects into the compensation chamber and which is of a shape that does not present circular symmetry.

The invention belongs to the technical field of cell detection apparatus, and relates to a micro-fluidic chip used for simultaneous detection of bladder cancer cells, calculi, blood cells, and bacteria in urine. The micro-fluidic chip is composed of a lower sample channel layer and an upper pneumatic microvalve layer used for controlling on-off of sample channels; the lower sample channel layer is composed of an urine sample inlet, an urine sample main channel, and an urine sample outlet liquid storage tank; a plurality of detecting units, including an urinary calculi interception unit, an urinary bladder transitional epithelial cancer detection unit, an urinary bladder adenocarcinoma cell detection unit, an urinary bladder squamous carcinoma cell detection unit, a blood cell detection unit, and a bacterium detection unit , are arranged on the urine sample main channel; and the detecting units are connected in series, and are arranged in a circular symmetry manner. The micro-fluidic chip is high in specificity and sensitivity, can be used for determining that whether a patient suffers from bladder cancer and urinary tract symptoms just via detection on urine, and is a cheap high-efficiency urine detection tool.

The invention belongs to the optical device technology field and discloses a gradient refractive index quartz glass lens. A refractive index along a radial direction in an internal portion is continuously reduced or continuously increased and the refractive index is distributed in a circular symmetry mode relative to a symmetrical shaft of a lens so that a maximum refractive index difference of the refractive index of the gradient refractive index quartz glass lens and a pure quartz glass refractive index is + / -0.08. The lens does not contain harmful heavy metal elements of thallium and lead. Under the condition that an antireflection film is not plated, a maximum ultraviolet-visible-infrared light transmittance can reach 91%, a lens length scope is 1-50mm and a diameter scope is 0.1-50mm.

The shape of a space circle is projected to a plane to form an ellipse under photographing of a single camera in the process of binocular visual measurement of an arc workpiece. The edge of the arc has certain notches or defects so that correct fitting of the ellipse and eliminating the edge error points have a significant impact on correct matching of the subsequent points and solving of the space circle radius. Fitting of multiple straight lines is performed by using an improved RANSAC algorithm to obtain the center point of the ellipse based on Hough transformation. Meanwhile, voting of the remaining three parameters is performed on the symmetry point of Hough transformation by using the symmetry of the ellipse so as to reduce the computational burden and enhance the accuracy. Finally, the feasibility of the method is verified by the experiment.

A method for simultaneously achieving circular symmetry and diminishing effects of optical defects and deviations during real time use of optical devices, and, a corresponding device and system for implementing the method thereof. The method features rotating an entire optical device, rotating at least one optical part of an entire optical device such as an optical assembly or an optical element during real time viewing or projecting by the optical device, in order to spread and blur the optical defects and deviations present in the at least one optical part of the optical device. In a first embodiment of the method, an optical rotation device is activated and controlled for rotating at least one optical part of an optical device during real time use of a viewing or projecting optical device. In a second embodiment of the method, there is included a step for aligning the optical axis of the at least one optical part of the optical device with respect to the rotation axis. In a first, simple, yet practical, embodiment of an optical rotation device for rotating the at least one optical part of the optical device, there are provided means and mechanisms for manual alignment during real time use of an optical device, whereas, in a second, more advanced, embodiment of an optical rotation device for effecting the rotation of the optical part of the optical device, there are provided means and mechanisms for highly accurate and automatic aligning of the optical axis of the optical part of the optical device with the rotation axis, thereby simultaneously achieving a high level of circular symmetry with respect to the optical part of the optical device, and significant diminishment of optical defects and deviations in at least one optical part of the optical device.

One upper and one lower bound on the search window for the code phase of a signal transmitted from a specific satellite (20) can be computed for terminals (10) that reside anywhere in a closed region (41), having a non-circular symmetry, obtained by an initial positioning step. A position is then determined using search windows having such upper and such lower bound for at least one satellite (20). The upper and lower bounds are provided using satellite position data in three dimensions (r, φ, Θ) satellite time reference data as well as geometric information about the closed region (41) of the initial positioning.

The invention discloses a scattered complex-amplitude pupil filter for generating an overlong light tube field, comprising a plurality of scattered concentric multi-ring wave zone plates in circular symmetry, wherein main transmitting ring zones and cut-off ring zones are sequentially and alternately arranged outwards along a radius direction by taking a cut-off circular region with the transmittivity of 0 as the center of a cycle, the outmost ring is one of the main transmitting ring zones, the phase delays of all the main transmitting ring zones are changed in a pi and zero inverse alternation way along the radius direction, and the transmittivities of all the main transmitting ring zones are gradually increased from inside to outside along the radius direction. The pupil filter is suitable for an azimuthally-polarizing incident vector light field, and an overlong hollow light tube field can be obtained through modulating the complex amplitude of the incident light field and focusing a beam by using a large-numerical-aperture focusing system. The diffraction-limited light tube field is a pure azimuthally-polarizing vector light field, the lateral diameter of a light tube is smaller than a half of optical wavelength, and the axial length of the light tube can be up to several wavelengths, and the light tube field can be applied to the capture and control of nano-dimension particles.

The invention relates to a combined fixture used for fixing an optical fiber stress rod. The combined fixture comprises a left fixing component and a right fixing component which are respectively used for clamping two sides of an optical fiber stress rod, wherein the left fixing component is of a hollow tubular shape, the outer surface of the left fixing component is provided with a flange, the flange is provided with a plurality of radial screw holes, each screw hole is internally provided with a screw pile which is provided with a clamping head and is connected with the screw hole by virtue of a screw thread, and the a screw pile is used for clamping one side of the optical fiber stress rod to be processed; one end of the right fixing component is of a closed tubular shape, the outer surface of the right fixing component is provided with a flange, the flange is provided with a plurality of radial screw holes, each screw hole is internally provided with a screw pile which is provided with a clamping head and is connected with the screw hole by virtue of a screw thread, and the clamping head is used for clamping the other side of the optical fiber stress rod to be processed; and a center hole is arranged at the center of the closed end of the right fixing component and is used for being matched with a center of grinding equipment, thus the whole fixture and the rotating shaft of the grinding equipment are coaxial. The combined fixture provided by the invention overcomes the defect that a clamping mechanism is very dependent on cone-shaped end of the optical fiber stress rod in the traditional scheme, and an optical fiber stress rod obtained by grinding has good circular symmetry.

The invention provides a method for eliminating circular symmetry phase computer-generated holography substrate fringe pattern distortion. After light emitted from an expanding light source passes through two arms of a Twyman-Green interferometer, equal inclination interference occurs, equal inclination interference circular fringes which are sparse in the center and dense on edges are generated and recorded through an electric coupling device, a circular grating is generated through concentric circular fringes which are generated through the equal inclination interference, and a computer-generated holography substrate is processed through opaque liquid so that a circularly symmetric two-value amplitude type grating is generated; the concentric circular strips etched on the circularly symmetric two-value amplitude type grating and the equal inclination interference circular fringes on the circular grating are set so that a moire fringe condition is formed; and a moire fringe pattern with fringe pattern distortion information and a moire fringe pattern without the fringe pattern distortion information are recorded through a computer, the two moire fringe patterns are compared, data are processed so that a computer-generated holography substrate fringe pattern distortion value is obtained, influence on an aspheric surface detection result by the computer-generated holography substrate fringe pattern distortion is eliminated through an artificially synthesized distortion pattern, and aspheric surface high-accuracy detection is achieved.

The invention belongs to the technical field of microwave sources in high power microwave technology, and specifically relates to a high band magnetically insulated transmission line oscillator with fast microwave oscillation starting and saturation and high power capacity. The high band magnetically insulated transmission line oscillator provided by the invention is of a circular symmetry coaxial structure and is composed of an outer cylinder, a gradient choke cavity structure, a main slow wave structure, an extraction cavity structure, a cathode, a carrier cathode and an electron collector. According to the high band magnetically insulated transmission line oscillator provided by the invention, since the gradient choke cavity structure is adopted, and the distance of first interaction cavities is increased, an electron beam emitted by a starting point of the cathode can pass by the surface of a first cavity, and fast microwave oscillation starting and saturation can be realized; moreover, the high band magnetically insulated transmission line oscillator provided by the invention can effectively reduce a radio frequency field, reduce the radio frequency breakdown risk of the slow wave structure and effectively improve the power capacity of the devices; and the high band magnetically insulated transmission line oscillator provided by the invention further increases the length of the cathode, can reduce the average emission current density of the cathode and is conducive to improving the electron emission uniformity on the surface of the cathode and prolonging the service life of the cathode. These improvements have important significance of improving the output power and pulse width of high ban MIMO.

The invention discloses a linear array expansion method, and belongs to the technical field of array beam forming. The method comprises the following steps: acquiring a received signal of a linear array; dividing the linear array into two sub-arrays according to odd and even array elements; calculating a received signal covariance matrix of the two sub-arrays formed by the odd and even array elements; constructing an extended receiving array signal according to the received signal covariance matrix; and performing beam forming and target detection by using a conventional beam forming technology or a minimum variance distortionless response beam forming technology. The problems of performance reduction and poor robustness under a low signal-to-noise ratio, non-circular symmetry requirementand limited application of a signal source signal, complexity and large calculation amount of the existing linear array expansion method are solved.

A coaxial connector junction includes first and second coaxial connectors. The first coaxial connector includes: a first central conductor extension; a first outer conductor extension spaced apart from and circumferentially surrounding the first central conductor extension; and a first dielectric spacer interposed between the first central conductor extension and the first outer conductor extension. The second coaxial connector includes: a second central conductor extension; a second outer conductor extension spaced apart from and circumferentially surrounding the second central conductor extension; and a second dielectric spacer interposed between the second central conductor extension and the second outer conductor extension. Each of the central conductor extensions and the outer conductor extensions has circular symmetry about the longitudinal axis, such that electrical properties of the engaged first and second coaxial connectors are substantially the same irrespective of the relative orientations of the first and second coaxial connectors about the longitudinal axis.