CN-122026820-A - Broadband amplitude limiting low-noise amplifier

CN122026820ACN 122026820 ACN122026820 ACN 122026820ACN-122026820-A

Abstract

The invention relates to the technical field of radio frequency front ends, in particular to a broadband amplitude limiting low-noise amplifier, which is characterized in that on the basis of a traditional broadband amplitude limiting low-noise amplifier, the input matching network unit and an amplitude limiter unit of a circuit are subjected to innovative topological transformation, a source-level negative feedback unit is fused, the remarkable optimization of noise coefficients in a broadband is realized, parasitic capacitance introduced by the amplitude limiter unit is integrated with the input matching unit, and according to the impedance matching requirements of different working frequencies, the parasitic capacitance of the amplitude limiter is absorbed as a part of the input matching network through dynamic transformation of circuit topology, so that the impedance matching of target frequencies is completed by utilizing parasitic parameters, the additional noise introduction to a signal path when the parasitic capacitance of the amplitude limiter exists independently in the traditional design is avoided, and the noise deterioration phenomenon caused by the parasitic parameter of the amplitude limiting unit is reduced radically.

Inventors

LIU CHENGPENG
HU BO
LIU JUNLIANG
Lan Xianggan

Assignees

乾鸿微(四川)电子有限公司

Dates

Publication Date: 20260512
Application Date: 20260104

Claims (7)

1. The broadband amplitude limiting low-noise amplifier is characterized by comprising a radio frequency amplifying unit, a direct current biasing unit, an amplitude limiting unit, an input matching unit, a negative feedback unit and an output matching unit; the input end of the amplitude limiting unit inputs radio frequency signals, and the output end of the amplitude limiting unit is connected with the input end of the input matching unit; the input end of the radio frequency amplifying unit is connected with the output end of the input matching unit and the power supply VCC, and the output end of the radio frequency amplifying unit is connected with the input end of the output matching unit; The input end of the direct current bias unit is connected with a power supply VCC, and the output end of the direct current bias unit is lapped between the output end of the input matching unit and the input end of the radio frequency amplifying unit; One end of the negative feedback unit is connected with the input matching unit, the amplitude limiting unit and the radio frequency amplifying unit, and the other end of the negative feedback unit is connected with the ground.
2. The broadband clipping low noise amplifier according to claim 1, wherein the clipping unit comprises a diode D 1b , a diode D 2b , a diode D 3b and a diode D 4b ; The positive electrode of the diode D 1b is input with a radio frequency signal and is connected with the input end of the input matching unit; The cathode of the diode D 1b is connected with the anode of the diode D 2b ; The negative electrode of the diode D 4b is connected with the positive electrode of the diode D 3b , and the positive electrode of the diode D 4b is connected between the positive electrode of the diode D 1b and the input end of the input matching unit in a lap joint mode.
3. The broadband limiting low noise amplifier according to claim 2, wherein the input matching unit comprises a capacitor C 1b , a capacitor C 2b , a capacitor C 3b and an inductor L 3b ; one end of the capacitor C 1b is connected with the anode of the diode D 1b and the cathode of the diode D 3b , and the other end of the capacitor C 1b is connected with the input end of the inductor L 3b through a capacitor C 3b ; the output end of the inductor L 3b is connected with the input end of the radio frequency amplifying unit; One end of the capacitor C 2b is lapped between the capacitor C 1b and the capacitor C 3b , and the other end of the capacitor C 2b is connected with the cathode of the diode D 2b , the anode of the diode D 4b , the radio frequency amplifying unit and the negative feedback unit.
4. A wideband limiting low noise amplifier according to claim 3, wherein said radio frequency amplifying unit comprises a transistor M 1b , a transistor M 2b , a resistor R 6b , a resistor R 5b , a capacitor C 4b and an inductance L 1b ; the grid electrode of the transistor M 2b is connected with the output end of the inductor L 3b and the output end of the direct current bias unit, the drain electrode of the transistor M 2b is connected with the source electrode of the transistor M 1b , and the source electrode of the transistor M 2b is connected with the negative feedback unit, the negative electrode of the diode D 2b and the positive electrode of the diode D 4b ; The grid electrode of the transistor M 1b is connected with a grounded capacitor C 4b , and the drain electrode of the transistor M 1b is connected with an inductor L 1b connected with a power supply VCC; One end of the resistor R 5b is connected between the power supply VCC and the inductor L 1b in a lap joint mode, and the other end of the resistor R 5b is connected between the grid electrode of the M 1b and the capacitor C 4b in a lap joint mode; One end of the resistor R 6b is connected between the ground and the capacitor C 4b in a lap joint manner, and the other end of the resistor R 6b is connected between the resistor R 5b and the gate of the transistor M 1b in a lap joint manner.
5. The wideband limiting low noise amplifier of claim 4, wherein said dc bias unit comprises resistor R 1b , resistor R 2b , resistor R 3b , resistor R 4b , and transistor M 3b ; The input end of the resistor R 1b is connected with a power supply VCC, and the other end of the resistor R 1b is connected with the drain electrode of the transistor M 3b ; The grid electrode of the transistor M 3b is connected with the resistor R 3b , and the source electrode of the transistor M 3b is connected with the ground terminal; One end of the resistor R 4b is connected with the resistor R 4b , and the other end of the resistor R 4b is lapped between the output end of the inductor L 3b and the grid electrode of the transistor M 2b ; One end of the resistor R 2b is connected between the resistor R 1b and the drain of the transistor M 3b in a lap joint manner, and the other end is connected between the resistor R 3b and the resistor R 4b in a lap joint manner.
6. The wideband limiting low noise amplifier of claim 5, wherein said negative feedback unit comprises an inductance L 2b ; One end of the inductor L 2b is connected to the source of the transistor M 2b , the capacitor C 2b , the anode of the diode D 4b , and the cathode of the diode D 2b , and the other end is connected to the ground.
7. The wideband limiting low noise amplifier of claim 4, wherein said output matching unit comprises an output matching network and a capacitor C 5b ; The input end of the output matching network is lapped between the drain electrode of the transistor M 1b and the output end of the inductor L 1b , and the output end of the output matching network is connected with the capacitor C 5b ; the output end of the capacitor C 5b outputs the amplified radio frequency signal.

Description

Broadband amplitude limiting low-noise amplifier Technical Field The invention relates to the technical field of radio frequency front ends, in particular to a broadband amplitude limiting low-noise amplifier. Background The broadband limiting low-noise amplifier is a key device with core amplifying and protecting functions in a microwave and radio frequency receiving and transmitting system, is widely applied to broadband receiving scenes such as radar, satellite communication, electronic countermeasure and the like, is generally arranged at the forefront end of a receiving link, and is a core hub for connecting external signals with a post-processing circuit, and the antenna and a signal receiving port are arranged next to the receiving link. The core function of the low-noise amplifier not only continues the core functions of the traditional low-noise amplifier, such as low-distortion amplification of weak broadband signals received by an antenna and stable gain provision for a later-stage circuit, but also integrates a broadband amplitude limiting protection mechanism, namely, when encountering abnormal conditions such as strong interference signals, burst pulses or electrostatic discharge, the low-noise amplifier can quickly start the amplitude limiting function, clamp the amplitude of an output signal within a safety threshold, and avoid the damage of the later-stage sensitive circuit caused by overvoltage and overcurrent. As a first line of defense and a signal preamplifier at a receiving end, the noise coefficient of the broadband amplitude limiting low noise amplifier directly determines the receiving sensitivity of the whole broadband system, the gain characteristic influences the uniform amplification effect of signals in a broadband, the linearity is related to the fidelity and the anti-interference capability of the broadband signals, and the amplitude limiting response speed, the amplitude limiting threshold precision and the consistency in the broadband are key for guaranteeing the stable operation of the system in a complex electromagnetic environment, so that the broadband amplitude limiting low noise amplifier becomes a core component for considering both the signal quality and the hardware protection in the broadband transceiver system. The broadband amplitude limiting low noise amplifier is formed by cascading an amplitude limiter and a low noise amplifier (shown in figure 1), integrates the advantages of the amplitude limiter and the low noise amplifying circuit, and the common source and common gate amplifier forms a core amplifying module and integrates the functional modules of amplitude limiting, biasing, matching and the like. The diode D 1a, the diode D 2a, the diode D 3a and the diode D 4a form an amplitude limiting diode array to realize clamping protection on an input excessively strong signal, and the C 1a、C2a and the L 1b on the input side form an input matching and filtering unit to ensure effective input of a wide-frequency-band signal and inhibit out-of-band interference. In the core amplifying link, the common source tube M 2a is responsible for primarily amplifying weak signals, and the common gate tube M 1a utilizes the low input impedance characteristic of the common source tube M 2a to reduce the Miller effect of M 2a, so that the working bandwidth of the amplifier is expanded, the isolation between the input end and the output end is improved, and the stability of the system is enhanced. The broadband amplitude limiting low noise amplifier has the advantages that the broadband low noise amplifier and the amplitude limiter are integrated on a single chip, the device is miniaturized, the inter-chip loss caused by external connection such as bonding wires is reduced through on-chip integration, and the parasitic parameters of the amplitude limiting module have negative influence on the low noise performance. Since noise is a core index of the wideband low noise amplifier, which directly determines the sensitivity of the receiver, the input matching structure generally selects the simplest L-shaped matching structure when the wideband low noise amplifier performs input impedance matching, so as to avoid the excessive differential input loss brought by the matching structure. And the limiter optimizes the insertion loss as much as possible under the condition of meeting the limiting power requirement. The total noise coefficient of the broadband low-noise amplifier is the sum of the self noise coefficient, all matching devices at the input end and the insertion loss introduced by the amplitude limiting devices. Disclosure of Invention The invention provides a broadband amplitude limiting low-noise amplifier aiming at the problem of noise deterioration caused by parasitic parameters of the traditional broadband amplitude limiting low-noise amplifier, and the remarkable optimization of noise coefficients in a broadband is realized by carrying out innovative topological tran