43results about How to "Reduce frequency conversion loss" patented technology

The invention discloses a novel hybrid integrated circuit for terahertz mixers, and relates to the technical field of transmission devices for electric communication. The novel hybrid integrated circuit comprises quartz substrate circuits, a GaAs substrate circuit, a radio frequency waveguide and a local oscillation waveguide. The GaAs substrate circuit comprises a GaAs substrate and a GaAs terahertz Schottky diode disposed in the GaAs substrate. The front of the GaAs terahertz Schottky diode faces upward. The two ends of a GaAs terahertz Schottky diode pad are respectively integrated with a section of GaAs-based micro strip transmission line or suspended micro strip transmission line, and the GaAs-based micro strip transmission lines or the suspended micro strip transmission lines are respectively and electrically connected with the quartz substrate circuits on the two sides. The integrated circuit reduces the difficulty in device micro assembly. Compared with the current commonly-used hybrid integrated circuit form, the diode assembly precision is improved, the frequency conversion loss of mixers can be reduced, and the test result of mixers is enabled to be closer to the designed result.

The invention provides a frequency-shift keying continuous wave (FSK-CW) radar which is formed by an FSK modulator, a microwave voltage-controlled oscillator, a microwave front end, an antenna, a microwave mixer, an intermediate-frequency low-noise amplifier, an FSK demodulator, a double channel reconstruction filter amplifier, a double channel analog-digital converter, a word synchronization signal generator and a DSP processor. On the basis of analyzing the fundamental principle of an FSK radar, the invention provides the most important principle of the design of a receiving system, provides a specific scheme for realizing FSK modulation, demodulation and synchronization, provides three schemes for realizing the microwave front end and provides an effective method for digital signal processing. According to the FSK-CW radar design and realization method, the lowest-cost and effective FSK radar can be produced; and the FSK radar is used for the field of traffic safety, and is used for realizing measurement of relative distance, speed and moving direction of target vehicles.

The invention discloses a multi-channel wideband millimeter-wave mixing system. When a first millimeter-wave signal is input from a radio frequency port of an IQ mixer, the first millimeter-wave signal and a first local oscillator signal are carried out in the IQ mixer. Down-conversion and then input to the bridge, the remaining two ports of the bridge output the first down-conversion signal (useful signal) and the second down-conversion signal (mirror signal) respectively, the RF switch selects the first down-conversion signal to pass through; the intermediate frequency signal from When the port of the RF switch is input, the RF switch selects one of the channels to conduct and transmit the signal to the bridge. The two ports of the bridge output two quadrature signals. The quadrature signal and the second local oscillator signal are in the IQ mixer. Perform up-conversion to obtain a second millimeter-wave signal. The mixing system of the present invention has the bidirectional characteristic of up and down conversion, and at the same time has the selectivity of high and low local oscillators, and can use different single sideband suppression schemes or image frequency interference suppression schemes for specific test scenarios.

The invention discloses a terahertz multifunctional device based on integrated technology, including a terahertz frequency doubler and a terahertz harmonic mixer. Its structure from left to right is: input fundamental waveguide microstrip transition, microstrip line short-circuit surface, four-tube frequency-multiplier diode, local oscillator matching circuit, mixing diode, RF matching circuit, input RF waveguide microstrip transition, IF low pass filter. The number of dielectric substrates is reduced so that the circuit is integrated on one substrate, which also reduces the number of cavities to be processed and makes the processing and assembly simple. On the other hand, the invention reduces the design and processing of waveguide transitions and reduces the cavity size. size.

The invention provides a portable terahertz semi-active color focal plane camera which comprises a local oscillator reference source, a terahertz multi-beam quasi-optical mixer and W terahertz irradiation source modules, W being the number of pre-obtained colours, and W being a natural number which is equal to or larger than 1. Each terahertz irradiation source module sends terahertz irradiation signals for irradiating on a detected target. Each terahertz irradiation source module comprises a terahertz irradiation signal frequency multiplier and a terahertz antenna. Local oscillator signals generated by the local oscillator reference source are subjected to frequency multiplication through the terahertz irradiation signal frequency multiplier, radiated by the terahertz antenna, and then, irradiates on the detected target. The camera in the invention is small in size, light in weight; capable of improving target identification capability in a complex background environment, excellent in anti-disturbance performance, capable of real-time imaging, and has good resolution and sensitivity.

The invention discloses a miniaturized double-balanced mixer, comprising: a first 3dB electric bridge, a second 3dB electric bridge, a third 3dB electric bridge, a fourth 3dB electric bridge, a first impedance matching circuit, and a second impedance matching circuit circuit, a third impedance matching circuit, a fourth impedance matching circuit, a first mixing diode, a second mixing diode, a third mixing diode, a fourth mixing diode, a first filter circuit, and a second filter circuit; the first The common node between the filter circuit and the second filter circuit is a transmission signal port. The miniaturized double-balanced mixer has high local oscillator power, good local oscillator isolation, large dynamic range, small frequency conversion loss, suppresses RF even-order products, and is small in size, suitable for miniaturized microwave radio frequency circuits. .