321results about How to "Lower noise figure" patented technology

A pressure distribution detection device is characterized in that a flexible array sensor unit (2) is sequentially connected with a signal conditioning and data acquisition unit (3) and a data display and analysis unit (4); the flexible array sensor unit (2) consists of a sensor array (1) and a Wheatstone bridge circuit; the sensor array (1) consists of sensor nodes; each sensor node is a strain disc (6); the strain discs (6) are arranged to form the sensor array (1) in a line and row manner; and each strain disc (6) constitutes the Wheatstone bridge circuit with three precision resistors with known resistance values. When ambient pressure is applied on the strain discs (6), the resistors change, and the variation information of the resistance value of the flexible array sensor unit (2) is collected through the signal conditioning and data acquisition unit (3) and is transmitted to the data display and analysis unit (4) after analog-digital conversion to be displayed and analyzed. The invention is applicable to such fields as biomechanical engineering, medical rehabilitation and rehabilitation assistant property detection.

The invention discloses a high-sensitivity satellite-borne ADS-B signal receiver. The high-sensitivity satellite-borne ADS-B signal receiver comprises a radio frequency circuit, a local oscillator (LO) circuit, a frequency mixing circuit, an intermediate-frequency circuit, an AD sampling circuit, a digital logic chip and a microcontroller. The radio frequency circuit is used for receiving and amplifying an ADS-B radio frequency signal and filtering out interference and out-of-band noise. The LO circuit is used for generating an LO signal. The frequency mixing circuit is used for conducting frequency mixing on the LO signal and the ADS-B radio frequency signal to obtain an intermediate-frequency signal. The intermediate-frequency circuit is connected with the frequency mixing circuit and used for filtering out an interference signal in the intermediate-frequency signal. The AD sampling circuit is connected with the intermediate-frequency circuit and used for achieving analog-digital conversion to obtain a digital intermediate-frequency signal. The digital logic chip is connected with the AD sampling circuit and used for processing the digital intermediate-frequency signal from the AD sampling circuit. The microcontroller is connected with the digital logic chip and used for receiving message information from the digital logic chip and storing the message information in a mini flash memory card. By means of the high-sensitivity satellite-borne ADS-B signal receiver, the problem that in the prior art, an existing ADS-B signal receiver is low in sensitivity is solved.

The invention relates to an eight-unit T / R (transmitting / receiving) basic module with a function of S-band multi-beam transceiving duplexing, applicable to large-scaled multi-beam active phased-array radar, especially S-band unified carrier measurement and control communication systems, and belongs to the technical field of microwave and millimeter wave communications. The module runs under the band of 2.0-2.3GHz and comprises an eight-circuit T / R unit, two one-to-eight power dividers, four combiners and a digital control unit. The module runs under the S-band; a double-channel high-suppression duplexer is used to suppress leakage of transmitted signals, a sideband interval of the transmitting band and the receiving band is only 80MHz for a transceiving duplexing system, and the transmitted signals can be prevented from jamming a preamplifier of a receiving branch even when output power of transmitted beams is up to +20dBm (1W).

The present invention discloses a low noise amplifier circuit adopting multiplex noise counteract, wherein the low noise amplifier includes a DC connected Balanced to Unbalanced transformer (Balun), a pair of cross coupling connected input transistor with source electrode respectively direct connected to two balancing ends of the Balanced to Unbalanced transformer and the grid respectively AC coupled connected to two balancing ends that different with Balanced to Unbalanced transformer; a pair of transistor load with the grid respectively AC coupled connected to two balancing ends of the Balanced to Unbalanced transformer, and two pairs of electric resistance-capacitance (R-C) high-pass filter network forms cross coupling configuration by connecting the input transistor, two pairs of electric resistance-capacitance high-pass filter network AC couples the input signal to grid of the transistor load tube. The main purpose of the present invention is to realize low noise coefficient and high linearity through multiplex noise counteract technology only consuming low power consumption at the same time.

The invention provides a multi-band low-noise amplification method and a multi-band low-noise amplifier. A multi-band low-noise amplifier circuit adopts two input terminals which respectively belong to two different bands (a high band and a low band); an inductor, capacitors and a transistor are arranged at each input terminal; the inductor, the capacitors and the input impedance of the transistor together form an input-series matching network; variable-capacitance elements are arranged in the multi-band low-noise amplifier circuit. Through tuning of the variable-capacitance elements in the input matching networks, the amplifier can work at a plurality of different bands; meanwhile, two resonance networks are connected in parallel to improve the gain and broaden the bandwidth; a relatively small noise factor and a relatively high gain can be achieved within multiple bands, and input-output 50 omega impedance matching is realized within multiple bands.

The invention provides a broadband CMOS (Complementary Metal-Oxide-Semiconductor Transistor) balun low noise amplifier which aims at disadvantages of a traditional cascode balun amplifier. The broadband CMOS balun low noise amplifier is formed by a cascode input stage, a differential common gate isolation stage and a resistive load stage; the cascode input stage is formed by a cascade stage resistor, a first capacitor, a second capacitor, a first NMOS (N-channel metal oxide semiconductor FET) pipe and a second NMOS pipe which adopt a connecting mode through capacitance cross coupling and body cross coupling; the differential common gate isolation stage is formed by a third capacitor, a fourth capacitor, a third NMOS pipe and a fourth NMOS pipe which adopt a connecting mode through capacitance cross coupling; the resistive load stage is formed by a common gate branch circuit load resistor RCG and a common source branch circuit load resistor RCS. The broadband CMOS balun low noise amplifier has the advantages of improving circuit gain and noise performances, improving differential output balance and eliminating dependence on off-chip inductance and on-chip inductance in a large area on the basis that broadband characters and single-end-differential conversion are guaranteed.

A negative-feedback type ultra-wideband signal amplification circuit is proposed, which is designed for integration to an ultra-wideband (UWB) signal processing circuit system for providing a low-noise amplification function to UWB signals. The proposed circuit architecture is characterized by the provision of a dual-step filter circuit on the input side, the provision of a resistive-type feedback circuit in the transistor-based amplification circuitry, and the provision of a common-source transistor-based amplification circuit on the output side. These features allow the proposed signal amplification circuit to have flat power gain, lower power consumption, low noise figure, and higher operational stability.

The disclosed system comprises two groups of acoustic surface wave oscillator composed of acoustic surface wave delay line, radio frequency amplifier and phasing network, and one group of mixer circuit composed of mixer, low frequency amplifier and low pass filter. Outputs of two groups of oscillator are connected to the mixer. The output of the mixer passing through low pass filter and low frequency amplifier outputs signal of difference frequency between two groups of oscillator. Two groups of delay line are fabricated on same substrate. Single-phase unidirectional transducer (SPUDT) structure is adopted in delay line so as to reduce insertion loss. Length of the long transducer is equal to distance between geometric centers of transducers. Comb structure is adopted, and gap between combs is equal to length of the short transducer in order to restrain unwanted mode of oscillation. The oscillator is operated at single mode so as to raise frequency stability (0.07 ppm).

The invention provides a front end of broad band radio frequency in the medium-short wave frequency band high dynamic range, and relates to the front end of the broad band radio frequency in a medium-short wave frequency band spreading signal receiving system. The invention overcomes the shortcomings existing in the prior structure that the front end of the radio frequency has high noise coefficient, small dynamic range, and low image rejection. The front end of the radio frequency adopts a two-stage frequency conversion and low medium frequency outputting structure; a radio frequency signal enters into a medium-frequency baseband signal processing part after passing through a pre-amplification module, a frequency conversion module, a variable gain amplifier module, and a high-frequency amplifier module. The intermediate-frequency baseband processing part conducts digital demodulation under the drive of a clock signal. The variable gain amplifier module is realized by a digital method, and the dynamic requirement of the system can be ensured by three circuits of digital variable gain amplifier modules. Two circuits of local oscillation signals of the frequency conversion module and a clock signal provided to the digital baseband processing part are produced by a DDS plus PLL method. The PLL multiplies the frequency of a quartz oscillator outputted signal, the signal is inputted to three circuits of DDS after being driven by a buffer, and the signal output is realized.

The invention provides a communication radio frequency front-end module and a communication radio frequency front-end communication method. The communication radio frequency front-end module comprises an antenna switch for switching transmission links, a diplexer for supporting multi-band frequency signal transmission, a power amplifier for transmitting output signals of a transmitter to the diplexer, and a low-noise amplifier for transmitting input signals to receiver. By regulating an impedance balance network, the communication radio frequency front-end module is arranged to a corresponding frequency range; the antenna receives signals of the corresponding frequency range, and the signals are transmitted to the low-noise amplifier by the diplexer in a differential mode signal form; the transmitter sends signals which are amplified by the power amplifier and then transmitted to the diplexer and then the antenna, at the same time, the diplexer transmits output signals to the low-noise amplifier in a common mode signal form, and the low-noise amplifier eliminates the common mode signals to achieve the isolation effect. The number of devices required by the radio frequency front end is effectively reduced, and requirements for supporting multiple communication radio frequency ranges, achieving small noise coefficients and according with practical application are met.

The invention provides a low-noise variable-gain mixer relating to an integrated circuit technology of radio-frequency communication. The low-noise variable-gain mixer mainly comprises a low-noise transconductance input stage circuit, a current division stage circuit, a variable load stage circuit, a gain switchover stage circuit and a frequency conversion stage circuit. The switchover of a mixer at two working modes of a high-gain mode and a low-gain mode is realized by a method for judging whether current is provided to a transconductance input stage and a current division stage by a switching control current mirror or not; and moreover, the power consumption can be saved when the mixer works at the low-gain mode. The characteristic of low noise is realized by the circuits of the mixer within the working bandwidth of the circuits of the mixer. Meanwhile, the aim of variable gain is realized. The working bandwidth is 0.7 to 2.85GHz, and the important frequency bands of 915MHz, 1.8GHz, 2.45GHz and the like are covered. The low-noise variable-gain mixer is suitable for being used in a multi-standard wireless communication receiving system. Moreover, the variable-gain mixer provided by the invention can be used for a first-stage circuit of a receiving machine and can also be comprehended as the combination of a low-noise amplifier and a mixer.

The invention belongs to the technical field of optical fiber amplifiers, which more particularly relates to a two-section erbium-doped optical fiber amplifier which has two sections and can control the gain. The optical fiber amplifier comprises a two-section erbium-doped optical fiber amplifying part and a gain control part, wherein the two-section erbium-doped optical fiber amplifying part comprises a 980mn pump laser source, a two-section erbium-doped optical fiber, an optical isolator, a signal and pump multiplexer, and a signal and pump demultiplexer; the gain control part comprises the signal input and output and the power measurement of output return light, as well as a controller of the pump laser device. The two-section optical circuit structure can effectively isolate an ASE noise in counterpropagation, thus optimizing the noise isolation performance of the amplifier. The gain control part can implement the gain control and optimization of the amplifier by monitoring the output power of the pump laser device.

The invention discloses a low noise amplifier for current reuse and noise cancellation. The amplifier comprises a common-source amplifier, a common-gate amplifier, a signal isolation and current reuse network and an off-chip receiving network, wherein the common-source amplifier comprises a first N-type metal oxide transistor, a first resistor, a third resistor, a first capacitor and a sixth capacitor; the common-gate amplifier comprises a second N-type metal oxide transistor, a second resistor, a second capacitor and a fifth capacitor; the signal isolation and current reuse network comprises a first resonant network and a second resonant network; the first resonant network consists of a first inductor and a third capacitor; the second resonant network consists of a second inductor and a fourth capacitor; and the off-chip receiving network comprises a second inductor, a signal source of an artificial antenna and an antenna internal resistor. The low noise amplifier in such a structure has a noise cancellation function and simultaneously reuses the static bias current of the common-gate amplifier and the common-source amplifier, thereby having a low noise coefficient and a low power consumption function.

The invention provides an ultra-wideband frequency mixer. The ultra-wideband frequency mixer comprises transition sections from a broadside coupling balun and a broadside coupling strip line of a local oscillator channel to a plane transmitting line, a coplanar waveguide of a radiofrequency channel, a medium frequency output channel and a frequency mixing diode pair, wherein the frequency of a local oscillator signal and the frequency of a radio frequency signal are mixed by input frequency mixing diodes of the local isolator channel and input frequency mixing diodes of the radiofrequency channel respectively; generated medium signals are outputted via the medium frequency output channel; the broadside coupling balun is used for converting unbalanced ultra-wideband local isolator signals into balanced ultra-wideband local isolator signals; after the balanced local isolator signals are converted into input frequency mixing diodes of the plane transmitting line via the transition section, generated medium signals step across the coplanar waveguide by using a gold wire inductor and then are outputted via a microstrip line. By using the scheme, the working frequency can cover an ultra-wide frequency range of 0.01GHz-110GHz; the ultra-wideband frequency mixer can work in a fundamental wave frequency mixing mode in a frequency range of 0.01GHz-70GHz, and the frequency conversion loss and a noise coefficient index can be lower than 12dB; and the ultra-wideband frequency mixer can work in a frequency range of 70GHz-110GHZ in a triple frequency harmonic frequency mixing mode, and the frequency conversion loss and the noise coefficient index can be lower than 30dB.

The invention relates to a high-gain wideband low-noise amplifier, which is characterized in that an active transconductance enhancing circuit is adopted, a high-frequency choke unit, a load unit, a first input amplification unit and a second input amplification unit are arranged, a radio-frequency input signal is respectively connected with the input ends of the first input amplification unit and the second input amplification unit, the output end of the first input amplification unit outputs the amplified signal to the second input amplification unit, the output end of the second input amplification unit is connected with the load unit, the load unit outputs a radio-frequency output signal, and the input end of the second input amplification unit is serially connected with the high-frequency choke unit and then is grounded.

The invention provides a millimeter wave high-power low-noise reception front-end, and aims to provide a reception front-end to solve difficulties of high-power burnout resistance and large dynamic range of a millimeter wave low-noise receiver. The millimeter wave high-power low-noise reception front-end is realized according to the following technical scheme: when high-power radio frequency input signals enter the reception front-end, firstly N-channel power division is performed through a microstrip power-dividing network to form N channels of radiofrequency signals, the power of each channel of signals is reduced to 1 / N of that of the radio frequency input signals, amplitude limiting of each channel of radiofrequency signals is performed through an amplitude limiter, the power of each channel of signals is limited in the milliwatt magnitude, then the signals are amplified through a low-noise amplifier connected with the amplitude limiter in series and sent to a power synthesis network, power synthesis of the N channels of signals is performed, and a channel of radiofrequency signals are output through synthesis. According to the millimeter wave high-power low-noise reception front-end, the input power of each amplitude limiter is greatly reduced, the power burnout resistant indexes of the reception front-end are greatly increased, 1dB compression points of the synthesis signals are greatly increased compared with single-channel signals, and the dynamic range of the reception front-end is extended.

The invention discloses a Ku-waveband multi-channel switching receiving device. The Ku-waveband multi-channel switching receiving device comprises an antenna array, a multi-channel switching array and a main control module, wherein the antenna array comprises a plurality of antenna array elements for receiving Ku waveband signals; the multi-channel switching array is connected with the output of the antenna array, and comprises a plurality of switching layers formed hierarchically; each hierarchy of switching layer comprises a plurality of shift switches; the shift switches of each hierarchy of switching layer are used for combining two paths of channels output by a higher hierarchy of switching layer into one path of channel for outputting; and the main control module is communicated with each shift switch respectively, and is used for selecting and controlling a part of channels in the multi-channel switching array to be opened or closed. Channels for receiving Ku-waveband radio frequency signals are gated through the multi-channel switching array, so that certain channels can be specified to be in open states according to a set switching frequency, and meanwhile the remaining channels are in closed states.

The invention discloses a microwave integrated module of a PIN transmit-receive switch and a limiter. The microwave integrated module comprises a transmitting branch, an antenna branch, a receiving circuit and a detection circuit. The transmitting branch is composed of a blocking condenser, a tandem switch PIN tube and a choke inductor; the receiving circuit is composed of a 1 / 4 wavelength transmission line, an earth parallel switch PIN tube, a small power amplitude limiting PIN tube, an earth parallel choke inductor and an amplitude limiting control choke inductor; the transmitting branch is composed of a blocking condenser and a coupler; and the detection circuit is composed of a detector diode, a capacitor and a resistor. The earth parallel switch PIN tube on the receiving branch is shared by a transmit-receive switch function and an amplitude limiting function, thereby reducing the number of cascaded PIN tubes of the receiving branch and reducing the insertion loss of the reducing branch on the premise of guaranteeing the power capacity of the switch and the limiter.

The invention discloses a variable gain low-noise driving amplifier. The amplifier has a fully differential cascode structure, wherein a common gate consists of three side-by-side silicon germanide bipolar transistors; the central silicon germanide bipolar transistor adopts parallel capacitive feedback, a reasonable input / output matching circuit is adopted, a high variable gain is provided for a circuit, and the noise coefficient is reduced; a cascade circuit provides a high variable gain and increases the reverse isolation of the circuit at the same time; and a common source amplifying circuit further improves the gain of the circuit. By controlling the selection of an external bias, the variable gain with a 3dB step length is obtained. The variable gain low-noise driving amplifier has the characteristics of high variable gain, low noise and low power consumption.

The invention discloses an ultra-wideband miniaturized radio frequency module. An input signal passing a low pass filter A (1) and a limiter (2) and a calibration signal passing a single knife doublethrow switch A (3) are selected by a single knife double throw switch B (4), and then selected through a single knife four throw switch A (5); then power control is performed through a low noise amplifier A (6), a low noise amplifier B (7), a direct connector (8) and one of the four ways of a fixed attenuator; then power adjustment is performed through a single knife four throw switch B (10), a numerical attenuator (11) and an amplifier A (12); then selection is carried out by a single knife six throw switch A (13), and frequency selection is carried out through one of the six ways of a band-pass filter; and a local oscillator signal passes a mixer (26) and a low pass filter B (27) to obtain an intermediate frequency signal. The ultra-wideband miniaturized radio frequency module solves theproblems of the ultra-wideband low noise design, the gain flatness control, the anti-interference and the miniaturization.

The invention provides a spinning target time-varying three-dimensional imaging method based on a linear frequency modulation stepped signal. The spinning target time-varying three-dimensional imaging method comprises the steps of: step 1, subjecting data echo to ''Dechirp'' and translational motion compensation processing, carrying out range-slow time imaging, processing an obtained coarse-resolution range image, and synthesizing to obtain a fine-resolution range image; step 2, extracting echo curve parameters of scattering points in the fine-resolution range image through Hough transform, further acquiring echo trajectories of the scattering points; step 3, and performing interference processing on three antenna echoes along the trajectory directions to obtain two-dimensional coordinates, further performs range walk compensation on range direction positions represented by the trajectories to obtain three-dimensional coordinates, and finally acquiring a three-dimensional image of the scattering points through integrating the obtained three-dimensional coordinates. According to the spinning target time-varying three-dimensional imaging method, the linear frequency modulation stepped signal has a narrow instant bandwidth and has a large synthetic bandwidth at the same time, and the spinning target time-varying three-dimensional imaging method can be applied to a narrowband radar to improve the imaging quality and reduce the burden on a hardware system.

The invention discloses a broadband low-power-consumption and low-noise amplifier applied to a wireless sensor network. The amplifier comprises an input matching circuit, a first-level amplifier circuit and a second-level amplifier circuit which are connected in sequence. The first-level amplifier circuit is a resistor feedback common source circuit structure. The second-level amplifier circuit is an active parallel feedback common gate circuit structure.

The invention discloses a KU wave-band low noise amplifier. The KU wave-band low noise amplifier comprises a first-stage cascade-inductance-source-stage negative feedback structure, an inter-stage matching network and a second-stage cascade-inductance-source-stage negative feedback structure; the first-stage cascade-inductance-source-stage negative feedback structure is connected with the second-stage cascade-inductance-source-stage negative feedback structure through the inter-stage matching network. The KU wave-band low noise amplifier has the advantages that (1) the work frequency band ranges from 12 GHz to 18 GHz; (2) the minimum value of the gain (S21) is 20 dB, and the good gain flatness is achieved; (3) the noise factor of an input matching S11 and the noise factor of an output matching S22 are smaller than -10 dB in the work bandwidth; (4) K is larger than 1 in a wave band; in other words, the circuit meets the requirements of the unconditional stability.

The invention belongs to the technical field of radio frequency integrated circuits and particularly relates to an ultra wide band low noise amplifier circuit. The ultra wide band low noise amplifier circuit comprises a first field-effect tube, a second field-effect tube, a first resistor, a second resistor, a third resistor, a first inductor, a first capacitor and a second capacitor, and the first capacitor and the second capacitor are grounded. The ultra wide band low noise amplifier circuit can provide low noise coefficient, high and flat gain and good input and output matching in ultra-wide band.

The invention relates to a maritime ultra-short wave beyond visual range communication device, and belongs to the technical field of the communication device. The device is composed of a radio frequency receiving unit, a radio frequency transmitting unit, a baseband unit and so on. The device is characterized in that an antenna is connected with the radio frequency transmitting unit and the radio frequency receiving unit through an electronic switch. The radio frequency transmitting unit and the radio frequency receiving unit are connected with the baseband unit. The radio frequency transmitting unit is composed of an excitation module and a power module. The radio frequency receiving unit is composed of a radio frequency front end module, a frequency conversion module, an intermediate frequency amplification unit and an intermediate processing module. The baseband unit is composed of a DSP digital signal processing unit, an FPGA field-programmable gate array module. The device has the advantages that the noise coefficient is low, the sensitivity is high, the dynamic range is wide, the low signal to noise ratio demodulation is accurate, the multi-path interference of remote communication can be reduced, the maritime beyond visual range communication distance is long, the communication quality is good, and the existing problems that the multi-path interference of the remote transmission is serious, the noise interference is high, the beyond visual range communication cannot be realized, and the maritime beyond visual range communication quality is influenced are solved.

The invention belongs to the fields of optical fiber communication systems and optical interconnection, and aims to achieve the advantages of small size, low cost, high reliability, rich functions and the like of monolithic integration. The invention provides a photoelectric detector compatible with a standard SiGe bipolar complementary metal-oxide-semiconductor transistor (BiCMOS) process, and a high-speed and high-sensitivity monolithic integrated optical receiver integrated with the detector. To meet the technical requirements, the standard SiGe BiCMOS process-based optoelectronic integrated receiver comprises two photoelectric detectors with completely symmetrical structures, a trans-impedence amplifier with a full differential structure, a group of sequentially cascaded full differential limiting amplifier and an output buffer stage which is used for converting differential voltage signals output by the limiting amplifier into single-end output voltage signals and providing driving force. The optoelectronic integrated receiver is mainly applied to design and manufacture of the optical fiber communication systems.

The invention discloses an improved double Gilbert structure radio-frequency orthogonal upper frequency mixer. The frequency mixer comprises a transconductance level circuit, a switching level circuit and a tail current source circuit. Silicon germanium double pole-complementary metal oxide semiconductor process technology is adopted in the integral circuit; and the frequency mixer combines the advantages of a bipolar device and a complementary metal oxide semiconductor, and can improve the conversion gain at the same time of effectively reducing circuit noise. The transconductance level circuit has a parallel-connection structure of three pairs of transconductances, and improves the linearity of the frequency mixer at the same time of increasing the transconductance parameter of the transconductance level. The switching level circuit works in an ideal switching state according to the simulation result. A current injection mode is also adopted in the circuit, and partial current is extracted at the emitter of the switching level so that the current of the switching level is low enough and the hot noise and the flicker noise of the circuit are effectively reduced. According to the design, the frequency mixer works at 1.95GHz and can be applied in personal communication service and wideband code division multiple access communication systems.

The invention discloses a cascaded distributed low-noise amplifier. The cascaded distributed low-noise amplifier comprises a first stage amplifier, a second stage amplifier, and a third stage amplifier; each of the amplifiers is composed of a gain and an on-chip inductor, and the structures of the gain units of the amplifiers are completely same; the on-chip inductor and the input impedance of each gain unit form an input artificial transmission line, and the on-chip inductor and the output impedance of each gain unit form an output artificial transmission line. And the gain units of the amplifiers adopt the structure in single-end input to differential output. The low-noise amplifier disclosed by the invention is simple in structure, low in input echo loss, small in in-band fluctuation, high in gain, and low in noise coefficient; the limitation on the gain bandwidth product in the traditional amplifier can be overcome, the large flat gain can be obtained in wide frequency band, and the good noise performance is realized.

The invention belongs to the technical field of data link wireless communication, in particular to a dual-antenna radio frequency front-end module based on the principle structure of the internal dual-antenna working mode of a full-duplex radio frequency front-end. In this module, the output power of the upper and lower antennas at a certain frequency point is controlled by phase shifter, and thetransmit power is synthesized by phase shifter. All the frequency points covered by the upper and lower antennas are distinguished by two different groups of cavity filters in the form of high and lowbands. The filters in high and low bands have a high degree of suppression and can achieve full-duplex operation. In the receiving part of the high-power limiter can ensure that in the antenna port open state, when the high-power signal is totally reflected, the receiving circuit can be protected, and the high-power signal is reflected to the load port. The limiter is used to prevent high power signals from entering the receive link and to protect the receive channel components.

The invention relates to the technical field of radio frequency, and discloses a tunable broadband low-noise amplifier. The tunable broadband low-noise amplifier comprises a matching network, a switched capacitor output frequency selection network and an amplifying circuit; a signal input end is connected with the matching network for noise matching; the amplifying circuit is of a common-source common-gate structure. The grid of the first transistor is connected with the matching network; the grid electrode of the second transistor is grounded after being connected with a third capacitor, thesource electrode of the first transistor is grounded after being connected with a third inductor, the drain electrode of the second transistor is grounded after being connected with a fifth inductor and a fourth capacitor, the drain electrode of the second transistor is further connected with a switched capacitor output frequency-selecting network and a fourth inductor, and the fourth inductor isconnected with a signal output end. According to the structure, the switched capacitor can be adjusted to output the frequency-selecting network, and the conversion of the working frequency is realized, so that the performance of the low-noise amplifier on each frequency band is improved, the gain and noise indexes are improved, and the receiver sensitivity is improved. The input network with thestructure has broadband characteristics, and the output network has narrowband and tunable characteristics.