14 results about "Degenerate mode" patented technology

The invention discloses an impedance mismatch design method for a gas turbine combustion chamber multi-flame-tube cross-flame system, which comprises the following steps: forming a combustion chamber by 12 flame tubes in a gas turbine through cross-flame tubes on the basis of a graph theory, modeling as a cyclic graph, and constructing an adjacent matrix and a Laplacian matrix; constructing a system matrix based on the angular frequency of the flame tube and the coupling strength of the cross flame tube; calculating a characteristic value and a characteristic vector of a system matrix, determining an oscillation frequency and a vibration mode, and identifying a degenerate mode; by modifying the coupling strength of at least one cross flame tube and recalculating the eigenvalue and eigenvector of the system matrix, the degenerate frequency is split, and the symmetry is broken; and according to the frequency and the mode after splitting, parameters of the combustion chamber are adjusted to optimize the combustion stability. Modeling of a complex system is simplified based on a graph theory method, the calculation cost is reduced, the symmetry of the system is broken by modifying the coupling strength of the cross flame tubes, the degenerate frequency is split, and combustion instability is relieved.

This invention relates to a feature mode tracking method based on eigenvector correlation, belonging to the field of antenna technology, and includes two parts: preprocessing and post-processing. The preprocessing filtering method, targeting different radiation structures, retains only modes that significantly affect antenna performance. The post-processing sequentially addresses mode switching and mode degeneracy issues. In the mode switching problem stage, the tracking curve intersections are first identified, and a variance criterion is applied to determine if mode switching exists at the intersections. Then, eigenvector correlation is used for re-matching. In the mode degeneracy problem stage, degenerate mode pairs are first identified, and an energy criterion is applied for judgment. Then, degenerate mode pairs are corrected, and finally, the tracking curve is optimized to achieve a smooth tracking curve. Compared to traditional methods, this invention reduces the number of modes in the preprocessing stage, saving subsequent computation time, and classifies and handles mode tracking errors in the post-processing stage, ensuring the accuracy of the tracking results.

An eight-mode multiplexer / demultiplexer based on a refractive index step type non-degenerate mode main channel is characterized in that a transmission channel is formed by one eight-mode elliptical fiber core (EC) and seven single-mode fiber cores, and the elliptical fiber core at the coordinate center serves as a transmission main channel and penetrates through two sections; the single-mode fiber core serving as a side core is a transmission coupling channel, two ends of the single-mode fiber core are coupled, and the second section is arranged at the rear end of the longest coupling length of the first section; the length of a transmission main channel of the elliptical fiber core is 11.37 mm, the ellipticity rho of the elliptical core is 1.58, the length of a major semi-axis is 7.02 [mu] m, and the length of a minor semi-axis is 4.44 [mu] m; the length of the SMF-HG10 is 8.112 mm, the length of the SMF-HG01 is 4.976 mm, the length of the SMF-HG20 is 3.258 mm, the length of the SMF-HG11 is 1.190 mm, the length of the SMF-HG30 is 1.626 mm, and the length of the SMF-HG21 is 1.964 mm; the refractive index difference between the main modes of the multiplexer and the demultiplexer is greater than 1 * 10 <-3 >, the mode degeneracy of HG30 and HG02 is broken, and the mode preserving function is realized; the refractive index fiber core made of pure silicon dioxide is adopted to reduce loss; the side core is divided into two sections for coupling, so that low-loss and low-crosstalk multiplexing and demultiplexing of eight modes are realized, and MIMO-FREE operation is realized.

A broadband, low-error on-chip coupler based on quasi-degenerate mode technology includes: multiple stacked ground layers on the chip, and a first coil and a second coil coupled to each other on the top ground layer. The coils are not in contact with the ground layers. The two ends of the first coil are connected to an input port and a through port, respectively. The two ends of the second coil are connected to an isolation port and a coupling port, respectively. The ground layers are connected to an external ground level. This invention can accurately anchor the product of even-mode and odd-mode impedances to a 50Ω system impedance while achieving a quasi-degenerate mode state for the even-mode and odd-mode, i.e., keeping the phase constants of the even-mode and odd-mode close within the target frequency band, thus solving the phase mismatch problem in the broadband range. Experimental results show that in the 80–120 GHz frequency band, the phase difference between the output signals of the through port and the coupling port remains within ±1.1° compared to 90°, achieving orthogonal characteristics.

According to the angular velocity measuring device and method provided by the invention, the sapphire microwave cavity with high symmetry and low loss characteristics is configured, two microwaves in a degenerate echo wall mode with completely symmetrical propagation characteristics can be excited, and meanwhile, due to the high Q value characteristic of sapphire, the energy loss is low and the frequency stability is high in the signal propagation process; in the rotation process, microwaves in two degenerate modes are propagated in the rotation direction, the forward direction and the reverse direction of the cavity respectively, the linear speed brought by rotation of the cavity enables the effective propagation speed of the forward mode to be synchronously increased, the effective propagation speed of the reverse mode to be synchronously reduced, and the difference between the propagation speeds can be determined through the frequency difference. Therefore, the angular velocity of the rotation of the cavity can be measured with high precision.

According to the present disclosure, it is possible to reduce the difference in mode conversion efficiency occurring between degenerate modes of propagation in an optical fiber.　A mode converter (10) according to the present disclosure is provided with: a cladding (11); and, in the cladding, a core (12) that has a refractive index greater than the refractive index of the cladding, and a plurality of refractive index modulation portions (13A, 13B) that are provided so as to obliquely intersect the core and have a refractive index different from that of the surroundings. The mutually different refractive index modulation portions (13A, 13B) intersect the core (12) in mutually different directions in a cross section orthogonal to the longitudinal direction of the core.

The application discloses a millimeter wave polarization and pattern reconfigurable antenna and belongs to the field of radio frequency front-end devices. The millimeter wave polarization and pattern reconfigurable antenna is composed of symmetrical rectangular radiation patches, a half-circle defect, a quarter-circle defect and a rectangular branch loading located on the radiation patches, an orthogonal two-way feeding network, a T-shaped power division feeding network, a composite beam ohmic contact type MEMS switch, a direct current bias line, a test patch pad, a coplanar waveguide, a gradual matching structure, a dielectric substrate and a metal ground back plate. When unilateral MEMS switches on the T-shaped power division feeding network are turned on, energy flows to the radiation unit on the side, and the beam tilting effect to the left or the right can be realized. When the MEMS on both sides are turned on, the radiation pattern is directed to the Z positive axis, and there is no beam deflection, and accordingly, the pattern reconfigurable function of three directions, i.e. left, middle and right, can be realized. When the switches on the orthogonal two-way feeding network are turned on, the size of the long line can realize 90° phase delay, two orthogonal degenerate modes are combined to form circularly polarized waves, and complete half-power beam width is covered.

A gradient refractive index type transmission main channel few-mode multiplexer / demultiplexer based on optical field regulation and control is characterized in that a transmission channel is formed by an elliptical four-core super-mode fiber core FEC-SFC and three single-mode fiber cores, the elliptical four-core super-mode fiber core at the coordinate center serves as a transmission main channel, and the single-mode fiber cores SMF1, SMF2 and SMF3 are transmission coupling channels; the length of the transmission main channel FEC-SFC is 5.05 mm, and the lengths of the SMF1, the SMF2 and the SMF3 are also 5.05 mm; a low-loss and low-crosstalk non-degenerate mode super-mode and mode-preserving optical fiber (SMOF) core is designed as a main channel of a multiplexer and a demultiplexer, mode degeneracy of LP11a / LP11b is broken, a mode-preserving function is realized, light field regulation and control are provided to break mode degeneracy, effective refractive index difference between modes is enhanced and increased to solve mode crosstalk, and the mode-preserving function is realized. The refractive index fiber core made of pure silicon dioxide is adopted to reduce loss; the four super-mode multiplexing and demultiplexing of the LP01, the LP11a, the LP11b and the LP21b with the same magnitude length and high practicability are realized, and MIMO-FREE operation is realized.

The application discloses a method for impedance mismatch design of a multi-flame tube combined flame system of a gas turbine combustion chamber, comprising the following steps: based on graph theory, 12 flame tubes in a gas turbine are combined through a combined flame pipe to form a combustion chamber, modeling is performed as a cycle graph, and an adjacency matrix and a Laplace matrix are constructed; based on the angular frequency of the flame tube and the coupling strength of the combined flame pipe, a system matrix is constructed; eigenvalues and eigenvectors of the system matrix are calculated, oscillation frequency and vibration mode are determined, and degenerate modes are identified; by modifying the coupling strength of at least one combined flame pipe, the eigenvalues and eigenvectors of the system matrix are recalculated, degenerate frequency splitting is performed, and symmetry is broken; according to the split frequency and mode, the parameters of the combustion chamber are adjusted to optimize the combustion stability. The application simplifies the modeling of a complex system based on a graph theory method, reduces the calculation cost, breaks the symmetry of the system by modifying the coupling strength of the combined flame pipe, splits the degenerate frequency, and relieves the combustion instability.

The invention provides a non-degenerate mode few-mode optical fiber for light field regulation and control. The optical fiber is composed of a pure silicon dioxide elliptical fiber core with step refractive index distribution, a high-refractive-index microrod, air holes and a wrapping layer. According to the optical fiber, eight Hermitian non-degenerate mode operation with low crosstalk, low intrinsic loss and low bending loss is realized through a pure silicon dioxide elliptical fiber core and air hole structure, mode degeneration is broken through through the elliptical fiber core and microrod structure, optical field regulation and control and mode protection functions are realized, complex MIMO-DSP processing is eliminated, and the optical fiber has a wide application prospect. And the good performance of the MIMO-FREE application is realized.

The invention discloses a transmission metasurface structure (1), an antenna device and communication equipment. The transmission metasurface structure (1) comprises a first transmission type metasurface (12) and a second transmission type metasurface (13), wherein the first transmission type metasurface (12) is located between every two adjacent carrier layers (11); the first transmission type metasurface (12) comprises a first metal layer (121), a second metal layer (122) and a liquid crystal layer (123), a first metal strip (1211) of the first metal layer (121) is provided with a first aperture (1212), and a second metal strip (1221) of the second metal layer (122) is provided with a second aperture (1222). Gaps between the first metal strips (1211) and gaps between the second metal strips (1221) can ensure the transmission of electromagnetic signals; liquid crystal molecules in the liquid crystal layer (123) can be deflected to any angle to realize continuous regulation and control of the beam radiation direction; an electromagnetic signal can form a degenerate mode when propagating along the plurality of first transmission-type metasurfaces (12) so as to increase the bandwidth during propagation.

This invention discloses a method, antenna, and electronic device for binary amplitude shift keying (BSK) transmission based on the dual-polarization characteristics of dielectric waveguides, relating to the field of integrated circuit technology. It generates a guided wave signal possessing both BSK and dual-polarization characteristics based on binary amplitude shift keying modulation and dual-polarization. The guided wave signal is radiated, and the radiated signal is used to excite the dielectric waveguide in a dual-polarization manner, generating an excitation signal with two orthogonal degenerate mode transmission characteristics. The excitation signal is transmitted using the dielectric waveguide channel. The radiated signal is received and converted back into a guided wave signal. The guided wave signal is then processed. This invention achieves channel multiplexing of the dielectric waveguide, effectively doubling the channel capacity of the dielectric waveguide, expanding its channel capacity, and significantly improving the communication rate without increasing the transceiver circuitry. It effectively solves the low-bandwidth utilization problem under low-order binary amplitude shift keying modulation, increasing the maximum achievable communication rate.

The application discloses a kind of self-adapting electromagnetic suppression methods based on hemispherical harmonic oscillator, it is related to hemispherical harmonic oscillator electromagnetic suppression control field.The application carries out comprehensive quantitative analysis of frequency, damping and amplitude to orthogonal degenerate mode of hemispherical harmonic oscillator under the action of electromagnetic interference, accurately calculates frequency split error, damping imbalance and mode ellipticity, realizes dynamic balance of mode energy distribution and vibration mode stability control;Control vector can be adaptively iterated and updated, so that vibration mode frequency, amplitude and energy dissipation tend to ideal symmetrical state, vibration stability and mode symmetry are significantly improved, and reliable vibration regulation means is provided for high-precision microgyroscope and other applications.

A four-core main channel non-degenerate mode few-mode multiplexer / demultiplexer based on optical field regulation and control is characterized in that a transmission channel of the mode division multiplexer / demultiplexer is composed of an elliptical four-core super-mode fiber core FEC-SFC and three single-mode fiber cores, the elliptical four-core super-mode fiber core at the coordinate center serves as a transmission main channel, and the single-mode fiber cores SMF1, SMF2 and SMF3 are transmission coupling channels; the length of the transmission main channel FEC-SFC is 3.450 mm, and the lengths of the SMF1, the SMF2 and the SMF3 are 3.450 mm, 1.472 mm and 1.716 mm respectively; a low-loss and low-crosstalk non-degenerate mode super-mode and mode-preserving optical fiber (SMOF) core is designed as a main channel of a multiplexer and a demultiplexer, the mode degeneration of LP11a / LP11b is broken, the mode-preserving function is realized, a scheme for enhancing and increasing the effective refractive index difference between modes to solve the mode crosstalk is proposed, and the refractive index fiber core made of pure silicon dioxide is adopted to reduce the loss; according to the invention, multiplexing and demultiplexing of four kinds of super-modes of LP01, LP11a, LP11b and LP21b are realized, and MIMO-FREE operation is realized.