30results about How to "Good polarization stability" patented technology

The invention brings forward a broadband wave absorbing material with stable polarization, for solving the technical problems of poor polarization stability and not wide low-band bandwidth existing in a conventional wave absorbing material. The broadband wave absorbing material comprises a wave absorbing structure (1), an upper medium plate (2), a foam layer (3), a lower medium plate (4) and a frequency selection surface (5), wherein the wave absorbing structure (1) is printed on the upper surface of the upper medium plate (2), the frequency selection surface (5) is printed on the lower surface of the lower medium plate (4), the upper medium plate (2), the foam layer (3) and the lower medium plate (4) are successively arranged to form an up-down stacked structure, the wave absorbing structure (1) is formed by periodically arranging M*N metal broken line units (11) of dead square structures, and the frequency selection surface (5) is formed by periodically arranging M*N frequency selection surface units (51). The polarization stability is high, the absorption frequency band width is wide, the wave absorbing feature is high, the transmission feature at a high frequency is good, and the broadband wave absorbing material with stable polarization can be applied to such fields as antenna communication and absorption shielding and the like.

The invention relates to a fiber coupling output and vertical-cavity surface-emitting semiconductor laser, which comprises a vertical-cavity surface-emitting semiconductor laser. A collimating lens, a first half-wave plate and a polarization beam splitting prism are arranged in sequence along the output light direction of the vertical-cavity surface-emitting semiconductor laser; the polarization beam splitting prism splits the output light of the vertical-cavity surface-emitting semiconductor laser into p polarized light and s polarized light; the polarization state of the p polarized light is maintained; the s polarized light is transformed into p polarized light; and the two paths of p polarized light are integrated and output, thereby realizing the stable single-polarization output. The semiconductor laser has the advantages of low cost, optical fiber coupling, high power and stable single-polarization output, and is applicable to the optical fiber communication, optical interconnection, optical fiber link, parallel optical signal processing and the like.

The invention provides an optical fiber current sensing system which comprises a photoelectric detector, a signal processing unit, as well as a light source, a Y-shaped wave guide, a 45-degree welding point, a strip-shaped waveguide modulator, a polarization maintaining optical fiber and an optical fiber current sensing device which are sequentially connected with one another, wherein the Y-shaped wave guide is provided with a first branching end, a second branching end and a combining end, and is used for converting a light beam which is received from the light source through the first branching end into a linearly polarized light, receiving the light beam which is returned from the optical fiber current sensing device and carries the conductor current information from the combining end, and outputting from the second branching end; and the photoelectric detector is used for detecting the intensity of interference light outputted from the second branching end of the Y-shaped wave guide, converting the light intensity information into an electric signal, and transmitting to the signal processing unit. The optical fiber current sensing system adopts a double-waveguide structure, the polarization performance of a light path can be improved due to the Y-shaped wave guide, and the optical phase can be modulated due to the strip-shaped waveguide modulator, so that the light path has the advantages of being simple in structure and high in light path polarization stability.

The invention discloses a wave-absorbing surface with low profile and low incidence angle sensitivity. The wave-absorbing surface comprises a dielectric substrate, a two-dimensional plane periodic array printed on the front surface of the dielectric substrate and formed by arranging lossy frequency selection units, and a metal back plate, and the lossy frequency selection unit is formed by nesting a resistive square ring patch with an interdigital edge and a metal square patch. According to the invention, the wave absorbing rate can reach more than 90% in the working frequency band, and good performance stability can be maintained for incident electromagnetic waves with TE and TM polarization, a pitching incident angle in a range of 0-40 degrees and an incident angle in any direction. Compared with the prior art, the wave-absorbing surface has the advantages of being extremely low in profile, light in weight, convenient to process, high in wave absorbing rate in a working frequency band, good in polarization stability and angle stability and good in engineering application prospect.

A laser arrangement is provided, in which a Lyot filter arrangement is operative to effect single mode operation. The birefringent element of the Lyot filter arrangement has a cavity folding mirror on one side thereof and a polarizing element on another side thereof, such that the free spectral range of the Lyot filter is improved. Preferably, the Lyot filter arrangement and the laser gain material are located in different branches of the folded cavity.

A composition for forming a PZT-based piezoelectric film formed of Mn-doped composite metal oxides is provided, the composition including: PZT-based precursors containing metal atoms configuring the composite metal oxides; a diol; and polyvinylpyrrolidone, in which when a metal atom ratio in the composition is shown as Pb:Mn:Zr:Ti, the PZT-based precursors are contained so that a metal atom ratio of Pb is satisfied to be from 1.00 to 1.20, a metal atom ratio of Mn is satisfied to be equal to or greater than 0.002 and less than 0.05, a metal atom ratio of Zr is satisfied to be from 0.40 to 0.55, a metal atom ratio of Ti is satisfied to be from 0.45 to 0.60, and the total of Zr and Ti in a metal atom ratio is 1.

A dual-passband frequency selective surface structure and a unit structure thereof belong to the technical field of electromagnetic waves. The surface structure is characterized by comprising a metal layer and a dielectric substrate which are sequentially arranged from top to bottom; a cross-shaped gap and a stepped gap are formed in the metal layer; the center of the cross-shaped gap coincides with the center of the metal layer; the number of the step-shaped gaps is four, and the step-shaped gaps are located in four areas separated by the cross-shaped gap and sequentially rotate by 90 degrees around the center of the structure; and the cross-shaped gap is connected with the step-shaped gap. The dual-passband frequency selective surface structure has extremely strong filtering characteristics near two frequency points of 6.7 GHz and 18.1 GHz, satellite communication signals working at the dual frequency points can be protected from being interfered by other frequency signals, the resonant frequency has no deviation when TE and TM polarized incident waves are vertically irradiated, and in a TE mode and a TM mode, when incident waves are irradiated at different angles, the resonant frequency and the bandwidth are slightly changed, and the structural performance is not influenced.

The invention relates to a frequency selection surface structure applied to 5G communication and a unit structure thereof. The unit structure comprises a first dielectric substrate, a metal layer anda second dielectric substrate which are arranged in order from top to bottom, wherein the metal layer is provided with an improved Jerusalem gap and an improved square-ring gap; the improved square-ring gap surrounds the periphery of the improved Jerusalem gap, and the center of the improved Jerusalem gap and the center of the improved square-ring gap coincide with the center of the metal layer. The frequency selection surface structure comprises M*N periodically arranged unit structures. The frequency selection surface structure comprises dual-band band-pass features of 28GHz and 39GHz, and agood filtering effect; and moreover, the frequency selection surface structure has excellent polarization stability and angle stability, and when incident waves are incident at different angles in different polarization modes, the resonance frequency is always within a 5G frequency band.

The invention discloses a fractal-element-based frequency selective surface structure which comprises a first frequency selective surface layer and a first dielectric plate, wherein the first frequency selective surface layer comprises a plurality of patch elements; each patch element comprises a first fractal ring, a second fractal ring, a third fractal ring and a fourth fractal ring; the first fractal ring is a regular triangle ring; each side is provided with a U-shape bending part; the second fractal ring, the third fractal ring and the fourth fractal ring are located in the regular triangle ring and are in rotational symmetry distribution about the center of the regular triangle ring; the second fractal ring, the third fractal ring and the fourth fractal ring are quadrangle rings; the first vertex angle, the second vertex angle and the third vertex angle are 120 degrees, 90 degrees and 90 degrees in sequence; the fourth vertex angle is opposite to the first vertex angle; and two sides of the fourth vertex angle are provided with the U-shaped bending parts respectively. The frequency selective surface structure disclosed by the invention has good polarization stability; and the wave-transmitting characteristic can be effectively improved on the basis of keeping the wave-absorbing characteristic. Furthermore, the invention further discloses a frequency selective surface structure-based window absorber.

The invention discloses a 2.5D multi-layer frequency selection surface, which comprises a multi-layer strip lumped resistance wave-absorbing layer, an air layer and a metal reflection layer stacked in sequence from top to bottom. The absorption layer includes a first dielectric plate, a second Two dielectric boards, the first FSS layer, the second FSS layer and the third FSS layer, the first dielectric board and the second dielectric board are laminated, the first dielectric board is located on the second dielectric board, and the first FSS layer is located on the second dielectric board. The upper surface of a dielectric plate, the second FSS layer is located on the lower surface of the first dielectric plate, and the third FSS layer is located on the lower surface of the second dielectric plate. The present invention can effectively ensure the strong reflection characteristic higher than -1dB in the band, and has high stability.

The invention relates to a frequency selection surface structure applied to a Ku waveband and a unit structure thereof. The unit structure comprises a first metal layer, a dielectric substrate and a second metal layer which are arranged in order from top to bottom, wherein the first metal layer is provided with a first star-shaped gap, and the first star-shaped gap comprises a first polygonal gappart positioned at the center and a plurality of first triangular gap parts surrounding the first polygonal gap part; and a second star-shaped gap comprises a second polygonal gap part positioned at the center and a plurality of second triangular gap parts surrounding the second polygonal gap part. The frequency selection surface structure comprises M*N periodically arranged unit structures. The frequency selection surface structure has very high filtering features in the 12GHz frequency band and can prevent the broadcast signals of a satellite from being interfered by other frequency signalsin a downlink.

The invention brings forward a broadband wave absorbing material with stable polarization, for solving the technical problems of poor polarization stability and not wide low-band bandwidth existing in a conventional wave absorbing material. The broadband wave absorbing material comprises a wave absorbing structure (1), an upper medium plate (2), a foam layer (3), a lower medium plate (4) and a frequency selection surface (5), wherein the wave absorbing structure (1) is printed on the upper surface of the upper medium plate (2), the frequency selection surface (5) is printed on the lower surface of the lower medium plate (4), the upper medium plate (2), the foam layer (3) and the lower medium plate (4) are successively arranged to form an up-down stacked structure, the wave absorbing structure (1) is formed by periodically arranging M*N metal broken line units (11) of dead square structures, and the frequency selection surface (5) is formed by periodically arranging M*N frequency selection surface units (51). The polarization stability is high, the absorption frequency band width is wide, the wave absorbing feature is high, the transmission feature at a high frequency is good, and the broadband wave absorbing material with stable polarization can be applied to such fields as antenna communication and absorption shielding and the like.

The invention discloses an X-band ultra-wideband electronically controlled active frequency selection surface based on a PIN diode and a processing and testing method thereof. The 3-layer metal plate unit and the 2-layer dielectric plate unit are arranged at intervals, a circular gap is arranged in the center of the middle layer metal plate unit, the upper layer metal plate unit is attached to the upper layer dielectric plate unit, and the bottom layer metal plate unit is attached to the lower layer dielectric plate unit, The upper layer metal plate unit is provided with a patch slot horizontally, the upper layer metal plate unit is vertically arranged with an interdigital capacitor gap, and the center of the upper layer metal plate unit is provided with a square gap; the upper layer metal plate unit and the bottom metal plate The unit structure is the same, the bottom metal plate unit is rotated 90 degrees relative to the upper metal plate unit; the PIN diode is vertically arranged on the patch gap. It can adjust its own performance in real time according to the working state of the antenna system.

The invention discloses a dual-frequency FSS with closely spaced frequency response characteristics and a unit structure thereof, the unit structure includes a metal layer and a dielectric substrate, the metal layer is arranged on the dielectric substrate; the metal layer includes a bow A shape ring-shaped metal patch and a square ring metal patch, wherein the square ring metal patch surrounds the outer circumference of the bow-shaped ring metal patch, and the square ring metal patch is The center coincides with the center of the bow-shaped annular metal patch; the bow-shaped annular metal patch is connected end to end by a plurality of bow-shaped metal units to form a center-symmetric annular structure. The dual-frequency FSS includes M×N periodically arranged unit structures. The dual-band FSS has dual-band band-stop characteristics, which can achieve band-stop effects on the frequency bands 5.59-6.51GHz and 7.43-9.61GHz at a depth of ‑10dB, with excellent polarization stability and angular stability, and a small size , to meet the needs of device miniaturization.

The invention discloses a high-precision flexible piezoelectric film material local polarization method, which comprises the steps of firstly, adopting a local polarization process, and pressing and touching a film by taking a flat-head circular pressure head as an upper and lower electrode polarization pressure head; dividing the film into a surface A and a surface B which are respectively in contact with a positive electrode and a negative electrode, taking 500V as an initial voltage and then taking 500V as gradient boosting, and loading on each gradient voltage until the voltage is boosted to 5000V; and then preparing a pressure head with a circular structure, and eliminating an edge outer halo polarization area, specifically, respectively contacting the A and B surfaces of the film with the positive electrode and the negative electrode, loading by taking 500V voltage as initial voltage until the voltage is increased to 2000V, and simultaneously detecting a piezoelectric D33 value of the edge outer halo area until the D33 value of the edge area is reduced to 0. According to the PVDF film obtained through polarization by adopting the method, the polarization area can be accurately controlled. In addition, positive and negative voltage alternate polarization is adopted, the polarization piezoelectric coefficient is high, and the polarization stability is good.

The embodiments described herein are directed to providing a notched antenna element for improving polarization control without sacrificing gain, bandwidth, scan volume, recurring cost, or manufacturability. The notched antenna element includes a base portion comprising a plurality of contiguous first cross-sectional notched antenna elements, each of the plurality of first cross-sectional notched antenna elements configured in an end-loaded structure for increasing polarization stability; and an upper portion coupled to the base portion, the upper portion comprising a plurality of contiguous second cross-sectional notch antenna elements.

The invention discloses an ultrathin and flexible composite wideband microwave absorption structure. The ultrathin and flexible composite wideband microwave absorption structure comprises an impedance matching structure, a frequency selection surface structure, a medium bearing structure, an energy loss structure and a metal backboard which are sequentially stacked from top to bottom, wherein the frequency selection surface structure is in direct contact with the medium bearing structure, the impedance matching structure is bonded with the frequency selection surface structure by an adhesive film, the medium bearing structure is bonded with the energy loss structure by an adhesive film, the energy loss structure is bonded with the metal backboard by an adhesive film, the impedance matching structure and the energy loss structure are respectively made of magnetic medium materials with different electromagnetic properties, and the frequency selection surface structure comprises a plurality of metal patch units arranged periodically. The microwave absorption structure provided by the invention is simple in preparation process, is flexible in texture, ultrathin in thickness and wide in microwave absorption frequency band, and has excellent polarization stability and oblique incidence angle stability.