11 results about "Negative resistance circuits" patented technology

The invention discloses a single-port detection resonator resonant frequency on-line real-time measurement system for an MEMS gyroscope, and the system comprises a closed-loop drive circuit which is used for driving a resonator to resonate and outputting a drive detection signal; the first C / V conversion circuit converts the current into a detection voltage signal, and the on-off of the first C / V conversion circuit and the negative resistance circuit is controlled by a voltage control switch; the negative resistance circuit enables the equivalent input resistance of the first C / V conversion circuit to be a negative value so as to generate positive damping feedback force on the detection resonator; the multiplier is used for carrying out multiplication demodulation on the detection voltage signal and the driving detection signal, and the angular velocity of the MEMS gyroscope is output after the signals are filtered by the low-pass filter; the upper computer controls the on-off of the voltage control switch, the frequency fd and the frequency fs are calculated through fast Fourier transform by driving the detection signal and the detection voltage signal respectively, the frequency difference is obtained by solving the difference, and the resonant frequency of the single-port detection resonator is measured on the premise that the work of the MEMS gyroscope is not affected.

The invention provides a microwave common-time double-frequency miniaturized radiator. According to the miniaturized radiator, two transistors are adopted to respectively construct negative resistance circuits to compensate resonator energy loss of a microwave common-time dual-frequency oscillator, and then output signals of SIW resonators are radiated and output through metal patches coupled through cross slot gaps. Comprising a high-frequency-band active negative resistance circuit, a high-frequency-band input blocking capacitor C1, a low-frequency-band active negative resistance circuit, a low-frequency-band input blocking capacitor C2, a high-frequency-band input matching circuit, a low-frequency-band input matching circuit and an SIW dual-mode dual-frequency radiation type resonator. According to the invention, the dual-mode resonator gap coupling metal patches are adopted to realize the function of common-time dual-frequency oscillation signal radiation output, and the oscillation signal obtained by radiation has the advantages of high output power, high isolation and low phase noise.

The invention relates to a voltage-controlled oscillator circuit which comprises a resonant cavity, a cross coupling negative resistance circuit, a switched capacitor array, a switched negative resistance array and a programmable biasing circuit. Wherein the cross coupling negative resistance circuit, the switched capacitor array and the switched negative resistance array are respectively connected with the resonant cavity in parallel, and the output end of the programmable bias circuit is connected with the resonant cavity; the resonant cavity is used for forming a resonant loop of the voltage-controlled oscillator circuit; the cross coupling negative resistance circuit is used for providing basic negative resistance required for maintaining oscillation for the resonant cavity; the switched capacitor array is used for adjusting the oscillation frequency of the resonant cavity by changing the equivalent capacitance value of the resonant cavity; the switch negative resistance array is used for adjusting the equivalent negative resistance value of the resonant cavity; and the programmable bias circuit is used for injecting bias current into the resonant cavity and triggering oscillation starting of the resonant cavity. According to the voltage-controlled oscillator, the problems of overlarge parasitic capacitance and limited tuning range caused by a fixed negative resistance structure in a traditional voltage-controlled oscillator are effectively solved, and the frequency coverage range of the oscillator is remarkably expanded.

The application relates to an anti-saturation device for an electromagnetic current transformer, comprising a negative resistance circuit and a negative inductance circuit connected in series; the negative resistance circuit comprises a first resistor, a second resistor, a third resistor and a first operational amplifier, the first resistor is connected to the inverting input end of the first operational amplifier, the first resistor is also connected to the output end of the first operational amplifier, the second resistor is connected to the non-inverting input end of the first operational amplifier, the second resistor is also connected to the output end of the first operational amplifier, and the third resistor is connected to the non-inverting input end of the first operational amplifier; the negative inductance circuit comprises an inductor, a fourth resistor, a fifth resistor and a second operational amplifier, the inductor is connected to the inverting input end of the second operational amplifier, the inductor is also connected to the output end of the second operational amplifier, the fourth resistor is connected to the non-inverting input end of the second operational amplifier, the fourth resistor is also connected to the output end of the second operational amplifier, and the fifth resistor is connected to the non-inverting input end of the second operational amplifier.

The invention discloses a broadband voltage-controlled oscillator capable of effectively improving harmonic suppression and power fluctuation. The broadband voltage-controlled oscillator comprises a resonance circuit, a power supply circuit and a control circuit, wherein the resonance circuit is used for generating a frequency signal meeting a phase condition according to an electrically-controlled voltage; the negative resistance circuit is used for providing required energy for the frequency signal; the required characteristic circuit is used for changing the frequency response of the frequency signal so as to improve harmonic suppression and power fluctuation; the required characteristics of the required characteristic circuit include: the transmission characteristics of the required characteristic circuit are low-pass characteristics; the passband frequency of the circuit with the requirement characteristic is increased along with the increase of the electrically-controlled voltage; the passband transmission loss of the circuit with the requirement characteristic is reduced along with the increase of the passband frequency; under any electrically-controlled voltage, the passband frequency of the circuit with the required characteristic is lower than the second harmonic frequency of the broadband voltage-controlled oscillator. The output circuit is used for outputting a frequency signal whose frequency response is changed. According to the invention, the harmonic suppression of the broadband voltage-controlled oscillator is improved, and meanwhile, the power fluctuation is improved.

This invention discloses a dual-core magnetically coupled harmonic shaping millimeter-wave voltage-controlled oscillator (VCO), comprising a three-turn magnetically coupled transformer and a negative resistance circuit. The three-turn magnetically coupled transformer includes three inductors, and the negative resistance circuit includes two pairs of complementary PMOS and NMOS transistors. The gates of the two identical PMOS transistors are interconnected, and the gates of the two identical NMOS transistors are interconnected. The drains and gates of each pair of complementary PMOS and NMOS transistors are connected via an inductor. The two ends of the three inductors are respectively connected to a capacitor array-varactor circuit. The two ends of the inductors connected to the gates of the complementary PMOS and NMOS transistors are connected to an output buffer. The sources of each pair of complementary PMOS and NMOS transistors are connected to VDD and GND, respectively. This invention effectively suppresses parasitic coupling effects, improves harmonic shaping, and optimizes the phase noise performance of the VCO.

The application discloses a kind of electromagnetic multifunctional high-resolution sensors based on microwave negative resistance circuit compensation technology, and it relates to the field of sensor technology.The sensor of the present application comprises a passive resonant cavity, a first ring-shaped microfluidic chip embedded in the passive resonant cavity, a second ring-shaped microfluidic chip and a negative resistance compensation circuit.The passive resonant cavity is composed of an upper dielectric substrate and a lower dielectric substrate vertically superimposed.The present application connects the adjacent two layers of dielectric substrate around the hollow metal cylinder through the ring-shaped bottom metal layer, forms an equivalent inductor column in the center of the resonant cavity, and serves as the inner conductor of the short-circuit coaxial line.The cylindrical area around the inner conductor has a strong magnetic field, which serves as the magnetic permeability sensing area.The upper and lower second metal through holes are connected through the ring-shaped metal layer between the two polar plates, which is equivalent to a ring-shaped parallel-plate capacitor, forming the outer conductor of the short-circuit coaxial line.There is a strong electric field between the ring-shaped parallel-plate capacitor, which serves as the dielectric sensing area.

This invention discloses a method for fabricating a monolithically integrated low-phase-noise broadband voltage-controlled oscillator (VCO) and the VCO itself. The method includes fabricating an integrated circuit on a main substrate; forming a varactor mesa structure on a varactor substrate; thinning the back side of the varactor substrate; permanently bonding the processed varactor wafer to the main substrate; depositing a metal interconnect layer on the surface of the bonded main substrate to form a complete oscillation circuit; and dicing the bonded wafer into individual chips using a wafer dicing process to obtain the monolithically integrated low-phase-noise broadband VCO. This invention integrates a high-performance superjunction variable capacitor diode, a compound semiconductor microwave negative resistance circuit, and an oscillator circuit onto a single chip using heterogeneous integration technology, achieving a monolithically integrated low-phase-noise broadband VCO with advantages such as lower phase noise, a wider tuning range, and a smaller chip area.

The application discloses a multifunctional metamaterial beam amplified low-frequency multi-ferroelectric mechanical antenna, and relates to the technical field of antennas.The antenna is composed of a grid-shaped shuttle-shaped variable rigidity composite beam composed of a plurality of strong hysteresis magnetostrictive layers / high magnetic permeability magnetostrictive films / piezoelectric layer unit arrays, a first elastic substrate / soft piezoelectric material / second elastic substrate, a permanent magnet, an energy collection circuit and a negative resistance circuit.The elastic standing wave generated by exciting the piezoelectric array is enhanced through the variable rigidity characteristics of the elastic substrate in the composite beam and the strain convergence characteristics of the shuttle-shaped structure to enhance the magnetic moment oscillation effect of the permanent magnet at the end of the beam.The vibration of the permanent magnet and the magnetostriction effect of the magnetostrictive film jointly emit an alternating magnetic field.The planar grid structure and the vertical spiral structure of the metal elastic substrate form a low-frequency magnetic metamaterial through cascaded capacitance to amplify the emitted magnetic field;the soft piezoelectric material generates an alternating voltage when the composite beam vibrates, and the energy collection circuit supplies energy to the negative resistance circuit to further improve the Q value of the metamaterial and the magnetic field amplification effect.

This invention discloses a broadband voltage-controlled oscillator (VCO) based on magnetic coupling, comprising: a negative resistance circuit, a switched-shielded transformer, a switched capacitor circuit, a varactor circuit, an LC resonant cavity circuit, a mode switching switch circuit, and an output buffer circuit. The LC resonant cavity circuit includes a switched-shielded transformer, a tuning capacitor CT, and a fixed capacitor Cfix. There are two LC resonant cavities: one LC resonant cavity, named L1C1, consists of L11, L12, two sets of switched capacitors, two sets of Cfix, and one varactor connected in parallel; the other LC resonant cavity, named L2C2, consists of L21, L22, two sets of switched capacitors, and one varactor connected in parallel. A wide tuning range is achieved through two magnetic coupling methods: a mode switching switch and a switched-shielded transformer. This invention provides a broadband VCO based on magnetic coupling, aiming to solve the technical problem of achieving a wide frequency tuning range without degrading phase noise.

The application provides an inductive sensor conditioning circuit based on LC resonant circuit, which comprises the following steps: an inductive sensor is used as an inductor to form a resonant circuit with a capacitor, an active negative resistance circuit is connected to generate a sinusoidal resonant signal, and a signal processing circuit is used to measure the frequency and amplitude of the resonant signal; since the quality factor of the capacitor in the resonant circuit is much higher than that of the inductive sensor, the frequency and amplitude of the resonant signal can accurately reflect the impedance value of the inductive sensor. The application can accurately measure the impedance change of the inductive sensor through the above method, and realize self-temperature compensation of the sensor by using the measured data and algorithm.