4 results about "Degenerate mode" patented technology

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.

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.

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.