30results about How to "Adjustable center frequency" patented technology

The invention discloses a substrate integrated waveguide filter with independently adjustable double bands. The substrate integrated waveguide filter comprises a resonant cavity and a perturbation body on the resonant cavity, wherein the resonant cavity comprises a ground plane, a dielectric plate, a top-layer surface and metal wall via holes; the top-layer surface and the ground plane are located at the upper part and the lower part of the dielectric plate; the metal wall via holes are distributed in the periphery of the resonant cavity in an array at equal distances to form a wall; the hole pitch between two metal wall via holes is smaller than or equal to 2.5 times of the diameter of each metal wall via hole; the perturbation body comprises a perturbation trough, perturbation metal via holes and connecting troughs; the perturbation trough is located at the center position of the top-layer surface of the resonant cavity; the connecting troughs are symmetrically arranged about the perturbation trough; the perturbation metal via holes in each resonant cavity are symmetrical about the perturbation trough and correspondingly located in the connecting troughs; and the numbers of the connecting troughs and the perturbation metal via holes are even numbers. The SIW filter with the independently adjustable double bands has the advantages of being simple in structure, relatively large in return loss, independently adjustable in double bands and simple in operation.

The invention discloses a planar low-pass band-pass dual-frequency filter, which is fabricated on a dielectric substrate in the form of a printed circuit board, and the same surface of the dielectric substrate is respectively fabricated with an input terminal feeder head port1 for inputting electromagnetic wave signals, Output feeder head port2 for outputting electromagnetic wave signals, first transmission line (1), second transmission line (2), third transmission line (3), fourth transmission line (4), fifth transmission line (5), sixth transmission line (6) The seventh transmission line (7), the other side of the dielectric substrate is a ground plate. The planar low-pass band-pass dual-band filter disclosed by the present invention can adjust the band-pass center frequency in a large range under the premise of ensuring that the low-pass characteristics remain unchanged. The filter is composed of an open-circuit transmission line and a high-impedance line. The length and characteristic impedance enable the band-pass center frequency to be independently adjusted within a wide range, and has the advantages of adjustable frequency, good selectivity, low loss, and simple structure.

A tunable ultra-narrow linewidth optoelectronic oscillator based on a random Brillouin fiber laser is provided, comprises a first tunable laser (1), a second tunable laser (2), a coupler (3), a beam splitter (4), an intensity modulator (5), an erbium-doped fiber amplifier (6), a first circulator (7), a highly nonlinear optical fiber (8), a second first circulator (9), a single-mode optical fiber (10), a photodetector (11), a power divider (12) and a phase-locked loop system (13) which constitute a real-time feedback system so that the two lasers emitted by the two tunable lasers have a fixed and stable phase difference. The microwave signal with adjustable center frequency and narrow linewidth can be generated by using the modulating characteristic of intensity modulator, nonlinear characteristic of high nonlinear fiber, feedback characteristic of single mode fiber, wavelength tunable characteristic of tunable laser and microwave generation performance of photoelectric oscillator.

The invention discloses an adjustable negative group delay circuit, aiming to provide a negative group delay circuit with simple structure, low circuit insertion loss and no need for input and output matching circuits. The adjustable negative group delay circuit of the present invention includes: a section of microstrip line connected in series between the input port and the output port and N dielectric resonators with adjustable resonant frequency and unloaded quality factor, wherein: N adjustable dielectric resonators The resonator is equivalent to N different parallel RLC resonant circuits, which are located next to the microstrip line and fixed on the same printed board as the microstrip line; N dielectric resonators work in the transverse wave TE mode and are connected to the microstrip through wireless coupling. After the strip line is coupled with the microstrip line, N-band negative group delay is generated near the resonant frequency of N dielectric resonators; the input port impedance and output port impedance of the adjustable negative group delay circuit are the same as the microstrip line impedance. The invention can be widely used in technical fields requiring negative group delay and adjustable negative group delay.

An ultrahigh Q-value single-passband microwave photon filter comprises a tunable filter, an optical coupler, a single-sideband modulation module, a single-sideband suppression carrier modulation module, a microwave signal source, an optical isolator, an optical amplifier, a single-mode optical fiber, an optical circulator, an optical fiber circulation cavity, a photoelectric detector and a vectornetwork analyzer, wherein the tunable filter is connected with the optical coupler, the optical coupler is connected with the single-sideband modulation module and the single-sideband suppression carrier modulation module, the optical isolator is connected with the single-sideband modulation module, the single-mode optical fiber is connected with the optical isolator, the microwave signal source is connected with the single-sideband suppression carrier modulation module, the single-sideband suppression carrier modulation module is connected with the optical fiber amplifier, the optical fiber amplifier is connected with the optical circulator, the optical fiber circulation cavity is connected with the optical circulator and is connected with the photoelectric detector, the photoelectric detector is connected with the vector network analyzer, and the vector network analyzer is connected with a microwave of the single-sideband modulation module.

The invention belongs to the technical field of microwave communication equipment, and particularly relates to a dual-mode SIW tunable filter based on reconfigurable electromagnetic boundaries, which includes a square substrate integrated waveguide dual-mode resonator, multiple PIN diodes and input and output feeders; The axisymmetric position of the square substrate integrated waveguide dual-mode resonator is added with a perturbation slot, and the main mode TE is used 101 modulus and the first higher order modulus TE 102 The mode forms the passband of the filter; PIN diodes are loaded around the square substrate integrated waveguide dual-mode resonator to control the free switching of the electrical boundary and the magnetic boundary; the input and output feeders are connected with the square substrate integrated waveguide dual-mode resonator connected. The present invention proposes the idea of ​​using the on-off of the PIN diode to realize the reconfigurable electromagnetic boundary, realizes the adjustable center frequency and keeps the absolute bandwidth constant, and has good selectivity and out-of-band suppression level in the entire center frequency adjustment range. The whole filter circuit has a simple structure and is flexible and convenient to adjust.

The invention discloses a distributed optical fiber sensing device based on a chaotic laser coherence method, and a measurement method of the distributed optical fiber sensing device. Chaotic laser light which is emitted from a chaotic laser is divided into detection light and reference light; the detection light is amplified by a light amplifier and then emitted into a sending optical fiber through an optical circulator, and a backward Brillouin scattering light signal is generated in the optical fiber; the Brillouin scattering light signal is amplified by the light amplifier, de-noised by a tunable light filter and then emitted into an optical fiber coupler; the optical length of the reference light is regulated by a variable light delay line, and interferes with the backward Brillouin scattering light signal which is generated by the detection light at different positions in the sensing optical fiber in the optical fiber coupler; an interference beat frequency signal is detected by a photoelectrical detector; and Brillouin gain spectra at different lengths are obtained through a data acquisition device and a signal processing device and then output to a display device, so strain or temperature sensing detection is realized.

The invention discloses a reconfigurable optical all-pass filter, comprising: three optical couplers, N+2 optical phase shifters and N microrings; the output end of the first optical coupler, the second optical coupler The input terminal and the first optical phase shifter constitute the MZI 1 Structure, the output end of the second optical coupler, the input end of the third optical coupler, the second optical phase shifter, the third optical phase shifter and the first microring constitute the MZI 2 structure. The invention utilizes the interference characteristics of the Mach-Zehnder interferometer and the resonance characteristics of the microring to input the signal into the chip and pass through the MZI 1 structure is divided into two inputs to the MZI 2 structure, one signal is filtered by the microring, the other one passes through the phase shifter and waveguide, the two signals are processed by multiple cascaded all-pass microrings after the interference of the third optical coupler, and finally from the second coupling grating output. The invention realizes a flat amplitude-frequency response by changing the amplitude ratio and phase difference of the two signals and adjusting the coupling coefficient of the micro-ring, thereby realizing an all-pass filter.

The invention discloses wireless telecom equipment with the reconfigurable carrier frequency and the reconfigurable signal bandwidth and relates to the field of wireless communication. The technical key points are that a local oscillator unit of an up-conversion unit in an emitting channel and a local oscillator unit of a down-conversion unit in a receiving channel are chosen as frequency-adjustable local oscillator units, a control unit is utilized to control the signal frequency output by the local oscillator units, accordingly the center carrier frequency of the emitting channel or the receiving channel is adjustable, meanwhile an emitting filter of the emitting channel and a receiving filter of the receiving channel can be replaced in a mechanical installation method to achieve different bandwidth ranges and different center frequency filtering effects, and the signal bandwidth can be changed. Furthermore, the center frequency of the emitting filter and the center frequency of the receiving filter are respectively equal to the local oscillator signal frequency output by the emitting local oscillator unit and the local oscillator signal frequency output by the receiving local oscillator unit.

The invention discloses an optical all-pass filter. The optical all-pass filter comprises a first optical coupler, a second optical coupler, a first coupling grating, a second coupling grating, first, second, third and fourth optical phase shifters and a microring. By use of frequency response characteristics of the microring, two ways of signals with adjustable amplitudes and phases are transmitted into the microring from two different ports of the microring respectively and are output at the two ports of the microring after being subjected to interfered beam combination. Different system phase response spectrum widths are realized by changing the coupling state of the microring, system amplitude response is a constant unrelated to frequency through adjustment of the amplitudes and phases of the two ways of signals, so that the optical all-pass filter is obtained. On the basis of the optical all-pass filter, the invention discloses a microwave photonic filter with a high Q value and an ultrahigh inhibition ratio and a microwave photonic phase shifter with a broad work frequency range and no sinking of amplitude response in the work range.

The invention relates to a high-power radiator with adjustable frequency. The radiator with adjustable center frequency can be realized by changing the length of the antenna vibrator, the discharge distance and the air pressure. Combined with the charging power source and the pulse power source platform, different frequencies can be output in the same system. Radiation field of high power electromagnetic pulses. Compared with ordinary high-power broadband antennas, the present invention has the following characteristics: 1. Adjustable radiation frequency: under the excitation of the same pulse power source, the adjustment of the radiation frequency can be realized by replacing the vibrators with different lengths in the radiator without using Different power sources reduce the requirements and costs of EMP effects testing. 2 Adjustable discharge spacing: By setting the electrode spacing of the discharge switch to be adjustable outside the radome, the array of radiators can be realized and a higher radiation field strength can be obtained.