阅读说明：本技术 一种频段可重构的宽带低噪声放大器 (Broadband low-noise amplifier with reconfigurable frequency band ) 是由 王勇 陈满健 王振宇 杨涛 于 2021-07-27 设计创作，主要内容包括：本发明提供一种频段可重构的宽带低噪声放大器,属于射频集成电路技术领域。该放大器通过耦合线结构将宽带信号分成两个频段信号,使得电路可以针对每段信号的噪声、增益等性能进行优化设计,并通过单刀双掷开关切换实现了频率的可重构,具有低噪声、高增益、宽频带可重构的优点。同时本发明提升了电路设计的灵活性,同时更加有利于通信系统的小型化和集成化,且易于实现,具有很好的实用价值。(The invention provides a broadband low-noise amplifier with a reconfigurable frequency band, and belongs to the technical field of radio frequency integrated circuits. The amplifier divides a broadband signal into two frequency band signals through a coupling line structure, so that the circuit can be optimally designed according to the performances of noise, gain and the like of each band of signals, the frequency can be reconfigured through the switching of the single-pole double-throw switch, and the amplifier has the advantages of low noise, high gain and wide band reconfigurability. Meanwhile, the invention improves the flexibility of circuit design, is more favorable for miniaturization and integration of a communication system, is easy to realize and has good practical value.)

1. A frequency band reconfigurable broadband low-noise amplifier is characterized by comprising a broadband low-noise amplifier stage, a coupling line, a through end termination inductor, a through end termination capacitor, an isolation end termination capacitor, a high-frequency band amplifier stage and a single-pole double-throw switch;

the output end of the broadband low-noise amplifier stage is connected with the input end of a coupling line, the direct-through end of the coupling line is connected with the first rotating end of a single-pole double-throw switch, the direct-through end of the coupling line is connected with one end of an inductor, the direct-through end of the coupling line is connected with one end of a capacitor, the coupling end of the coupling line is connected with the input end of a high-frequency-band amplifier stage, the output end of the high-frequency-band amplifier stage is connected with the second rotating end of the single-pole double-throw switch, the isolating end of the coupling line is connected with one end of an isolating end of the capacitor, the direct-through end of the coupling line is connected with the inductor, the direct-through end of the coupling line is connected with the capacitor, the other ends of the isolating end of the coupling line are grounded, the input end of the broadband low-noise amplifier stage serves as the input end of the frequency-band reconfigurable broadband low-noise amplifier, and the fixed end of the single-pole double-throw switch serves as the output end of the frequency-band reconfigurable broadband low-noise amplifier;

the broadband low-noise amplifier stage is used for amplifying an input broadband signal and inputting the broadband signal to the input end of the coupling line, the coupling end and the straight-through end of the coupling line divide the amplified input broadband signal into a high-frequency band signal and a low-frequency band signal,

and the high-frequency band signal is amplified by the high-frequency band amplification stage and then selectively output together with the low-frequency band signal through the single-pole double-throw switch.

2. The wideband low noise amplifier of claim 1, wherein the wideband low noise amplifier stage is primarily for low noise amplification of an input wideband signal, and wherein gain fluctuations are reduced by compensation of a subsequent amplifier stage.

3. The wideband low noise amplifier of claim 1, wherein the wideband low noise amplifier stage consists of two inductively peaking cascode sub-amplifier stages based on resistive and inductive degeneration, wherein a single inductively peaking cascode sub-amplifier stage comprises a common-gate transistor, a common-source transistor, an inductor, a capacitor, and a resistor; the grid electrode of the common grid electrode transistor is connected with a grid electrode inductor, an intermediate inductor is connected between the source electrode of the common grid electrode transistor and the drain electrode of the common source electrode transistor, a load inductor is connected between the drain electrode of the common grid electrode transistor and a power supply, and the drain electrode of the common grid electrode transistor and the grid electrode of the common source electrode transistor are connected through a negative feedback network formed by serially connecting a resistor and a capacitor.

4. The wideband low noise amplifier according to claim 1, wherein the coupling line, the through termination inductor, and the through termination capacitor form a band coupling, and the frequency band reconstruction is achieved by adjusting the length, width, line spacing of the coupling line, and the values of the termination inductor and the termination capacitor to determine the frequency of the signal passing through the through port and the coupling port.

5. The wideband low noise amplifier of claim 1, wherein the high band amplifier stage is configured to increase the gain of the high band signal and compensate for gain attenuation of the wideband signal due to coupling via the coupling line, thereby reducing in-band gain ripple.

6. The wideband low noise amplifier according to claim 5, wherein the high band amplifier stage comprises two sub-amplifier stage structures, the first sub-amplifier stage is the same as the sub-amplifier stage of the wideband low noise amplifier stage and is an inductance peaking cascode structure based on resistance negative feedback and inductance negative feedback, the second sub-amplifier stage is a common-source amplifier structure, a load inductor is connected between a drain and a power supply of a common-source transistor, the drain and a gate are connected with a negative feedback network formed by connecting a resistor and a capacitor in series, and a source is connected to ground.

7. The wideband low noise amplifier according to claim 1, wherein if the gain of the low band signal obtained by amplifying the signal with the wideband low noise amplifier stage and passing through the coupling line through terminal is smaller than the gain of the high band signal, the low band amplifier stage is disposed between the first rotation terminal of the single-pole double-throw switch and the coupling line through terminal to reduce the in-band gain fluctuation.

8. The wideband low noise amplifier of claim 1, wherein the low band amplification stage employs the same circuit configuration as the high band amplification stage.

9. The wideband low noise amplifier of claim 1, wherein the single pole double throw switch comprises 4 switching transistors and one matching inductor.

Technical Field

The invention belongs to the technical field of radio frequency integrated circuits, and particularly relates to a broadband low-noise amplifier with a reconfigurable frequency band.

Background

At present, wireless communication technology is rapidly developed, and industries such as mobile phones, wireless local area networks, internet of things and digital high-definition televisions bring great changes to daily life modes of people, and simultaneously, higher requirements are provided for radio frequency chip design technology. The functional integration degree of many application devices is higher and higher, and a certain system is often integrated with a plurality of functional subsystems. For example, a mobile phone in civil use integrates the functions of GSM, W-CDMA, 5G, WIFI, Bluetooth, navigation and the like. Each sub-function system at the front end of the traditional multifunctional integrated equipment receiver works as an independent link, a large number of common modules such as a low-noise amplifier and a power amplifier are repeatedly used (different applications correspond to sub-function systems of different frequency bands), the size and the cost of the equipment are greatly improved, and meanwhile, the reliability and the maneuverability are obviously reduced.

In order to solve the problem that a plurality of low noise amplifiers are needed in a multifunctional integrated device receiver, researchers turn to ultra wide band low noise amplifiers capable of covering more network systems. An ideal lna has low noise, high gain, and good input-output matching in a desired frequency band, but optimal noise matching for low noise and conjugate matching for high gain cannot be satisfied simultaneously, and matching can be performed only over a relatively narrow bandwidth, and therefore, special structures are often required for designing an ultra-wideband lna.

At present, the structures of the ultra-wideband low noise amplifier have been proposed as a balanced amplifier, a distributed amplifier, and a parallel-series feedback amplifier. Although the balanced amplifier can work in the state of optimal noise or maximum gain, the balanced amplifier has the problems of large circuit size and high power consumption because two mixed networks and two separated amplifiers are needed; the bandwidth of the distributed amplifier is very wide, the cut-off frequency of the transistor can be realized theoretically, but the chip area is large and the power consumption is high due to the fact that a plurality of spiral inductors or transmission lines are used; the parallel-series feedback structure can provide good broadband matching and gain over the entire broadband, but it is difficult to satisfy the balance between noise and gain.

Therefore, it is necessary to design a band reconfigurable low noise amplifier having a bandwidth adjusting function, low noise, high gain, and excellent comprehensive performance in a wide band.

Disclosure of Invention

In view of the problems in the background art, the present invention aims to provide a wideband low noise amplifier with reconfigurable frequency band. The amplifier divides a broadband signal into two frequency band signals through a coupling end and a straight-through end of a coupling line structure which is connected with an inductor and a capacitor, frequency band selection is carried out through a single-pole double-throw switch, reconfiguration of a frequency band is achieved, and performances such as noise coefficient, gain and the like in the frequency band are in the optimal state.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a frequency band reconfigurable broadband low-noise amplifier comprises a broadband low-noise amplifier stage, a coupling line, a straight-through end connecting inductor, a straight-through end connecting capacitor, an isolating end connecting capacitor, a high-frequency band amplifier stage and a single-pole double-throw switch;

the output end of the broadband low-noise amplifier stage is connected with the input end of a coupling line, the direct-through end of the coupling line is connected with the first rotating end of a single-pole double-throw switch, the direct-through end of the coupling line is connected with one end of an inductor, the direct-through end of the coupling line is connected with one end of a capacitor, the coupling end of the coupling line is connected with the input end of a high-frequency-band amplifier stage, the output end of the high-frequency-band amplifier stage is connected with the second rotating end of the single-pole double-throw switch, the isolating end of the coupling line is connected with one end of an isolating end of the capacitor, the direct-through end of the coupling line is connected with the inductor, the direct-through end of the coupling line is connected with the capacitor, the other ends of the isolating end of the coupling line are grounded, the input end of the broadband low-noise amplifier stage serves as the input end of the frequency-band reconfigurable broadband low-noise amplifier, and the fixed end of the single-pole double-throw switch serves as the output end of the frequency-band reconfigurable broadband low-noise amplifier;

the broadband low-noise amplifier stage is used for amplifying an input broadband signal and inputting the broadband signal to the input end of the coupling line, the coupling end and the straight-through end of the coupling line divide the amplified input broadband signal into a high-frequency band signal and a low-frequency band signal,

and the high-frequency band signal is amplified by the high-frequency band amplification stage and then selectively output together with the low-frequency band signal through the single-pole double-throw switch.

Furthermore, the broadband low-noise amplifier stage is mainly used for low-noise amplification of an input broadband signal, and has the characteristic of very low noise, and the gain fluctuation of the broadband low-noise amplifier stage can be reduced by a mode of compensating the gain fluctuation of a post-stage amplifier.

Furthermore, the broadband low-noise amplifier stage consists of two inductance peaking cascode structure sub-amplifier stages based on resistance negative feedback and inductive negative feedback, wherein a single inductance peaking cascode structure sub-amplifier stage comprises a common-gate transistor, a common-source transistor, an inductor, a capacitor and a resistor; the grid electrode of the common grid electrode transistor is connected with a grid electrode inductor, an intermediate inductor is connected between the source electrode of the common grid electrode transistor and the drain electrode of the common source electrode transistor, a load inductor is connected between the drain electrode of the common grid electrode transistor and a power supply, and the drain electrode of the common grid electrode transistor and the grid electrode of the common source electrode transistor are connected through a negative feedback network formed by serially connecting a resistor and a capacitor.

Furthermore, the coupling line, the straight-through end termination inductor and the straight-through end termination capacitor form frequency band coupling, and the frequency of signals passing through the straight-through port and the coupling port is determined by adjusting the length, the width and the line spacing of the coupling line, and the values of the termination inductor and the termination capacitor, so that the frequency band reconstruction is realized.

Furthermore, the high-frequency section amplification stage is mainly used for improving the gain of the high-frequency section signal, compensating the gain attenuation caused by the coupling of the broadband signal through the coupling line and reducing the in-band gain fluctuation.

Furthermore, the high-frequency amplification stage comprises two sub-amplification stage structures, the first sub-amplification stage is the same as the sub-amplification stage of the broadband low-noise amplification stage and is an inductance peaking common-source and common-gate structure based on resistance negative feedback and inductance negative feedback, the second sub-amplification stage is a common-source amplification structure, a load inductor is connected between the drain electrode of the common-source transistor and a power supply, the drain electrode and the gate electrode are connected with a negative feedback network formed by serially connecting a resistor and a capacitor, and the source electrode is connected to the ground.

Furthermore, if the gain of the low-frequency-band signal obtained by amplifying the signal by the broadband low-noise amplifier stage and then passing through the coupling line straight-through end is smaller than that of the high-frequency-band signal, a low-frequency-band amplifier stage can be arranged between the first rotating end of the single-pole double-throw switch and the coupling line straight-through end to reduce the fluctuation of the in-band gain.

Further, the low band amplifier stage may employ the same circuit structure as the high band amplifier stage.

Further, the single-pole double-throw switch is preferably formed by connecting 4 switching transistors and a matching inductor, but is not limited to this structure.

The mechanism of the invention is as follows: the broadband signal amplified by the broadband low-noise amplifier stage is divided into two frequency band signals by a coupling end and a straight-through end of the coupling line structure by using a coupling line structure comprising a termination inductor and a termination capacitor, the two frequency band signals are amplified by a gain stage at the back and then are respectively connected to a single-pole double-throw switch for output, and the switching of the output of the high-frequency band signal and the output of the low-frequency band signal is realized by the switch, so that the low-noise amplifier band is reconfigurable. In addition, the invention utilizes the characteristic of high isolation of the single-pole double-throw switch to avoid the direct interference of signals of two frequency bands and improve the stability of the amplifier, so that the noise coefficient, the gain, the stability and other performances in the reconstructed frequency band are in the optimal state.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

the frequency band reconfigurable broadband low-noise amplifier provided by the invention divides a broadband signal into two frequency band signals through a coupling line structure, so that a circuit can be optimally designed according to the performances of noise, gain and the like of each band signal, such as gain improvement, gain fluctuation reduction and the like, and the frequency reconfiguration is realized through the switching of a single-pole double-throw switch, and the frequency band reconfigurable broadband low-noise amplifier has the advantages of low noise, high gain and broadband reconfigurability. Meanwhile, the invention improves the flexibility of circuit design, is more favorable for miniaturization and integration of a communication system, is easy to realize and has good practical value.

Drawings

Fig. 1 is a schematic diagram of a wideband low noise amplifier with reconfigurable frequency band in embodiment 1 of the present invention.

Fig. 2 is a circuit implementation structure diagram of a wideband low noise amplifier with a reconfigurable frequency band in embodiment 1 of the present invention.

Fig. 3 is a schematic diagram of a wideband low noise amplifier with reconfigurable frequency band in embodiment 2 of the present invention.

Fig. 4 is a noise performance diagram of a wideband low noise amplifier with a reconfigurable frequency band in embodiment 1 of the present invention.

Fig. 5 is a gain performance diagram of a wideband low noise amplifier with reconfigurable frequency band in embodiment 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following embodiments and accompanying drawings.

Example 1

A frequency band reconfigurable broadband low-noise amplifier is shown in figure 1, and comprises a broadband low-noise amplifier stage, a coupling line, a straight-through end terminating inductor, a straight-through end terminating capacitor, an isolation end terminating capacitor, a high-frequency band amplifier stage and a single-pole double-throw switch; the output end of the broadband low-noise amplifier stage is connected with the input end 1 of the coupling line, the straight-through end 2 of the coupling line is connected with the first rotating end of the single-pole double-throw switch, the straight-through end of the coupling line is connected with one end of the inductor Lc, the straight-through end of the coupling line is connected with one end of the capacitor Cc1, the coupling end 4 of the coupling line is connected with the input end of the high-frequency-band amplifier, the output end of the high-frequency-band amplifier is connected with the second rotating end of the single-pole double-throw switch, the isolation end 3 of the coupling line is connected with one end of the isolation end of the capacitor Cc2, the other ends of the coupling line, the coupling line and the isolation end of the capacitor are grounded, the input end of the broadband low-noise amplifier stage serves as the input end of the broadband low-noise amplifier, and the fixed end of the single-pole double-throw switch serves as the output end of the broadband low-noise amplifier.

The broadband low-noise amplifier stage is a first-stage amplifier and is responsible for low-noise amplification of an input broadband signal, and has the characteristics of very low noise and certain gain, and the gain fluctuation of the broadband low-noise amplifier stage can be reduced by a mode of compensating a later-stage amplifier. The through port 2 of the coupling line is connected with a terminating inductor Lc and a terminating capacitor Cc1, and mainly used for low-frequency band signals; the coupling end 4 mainly transmits the coupled high-frequency band signal; the high-frequency end amplification stage is a high-frequency end second amplification stage and mainly amplifies coupled high-frequency signals, the gain of a high frequency band is amplified to be approximately the same as that of a low frequency band, and because the gain of the signals amplified by the broadband low noise is higher in the low frequency band and the gain of the high frequency band is lower, the high-frequency band amplification stage is arranged to amplify the high-frequency band signals to be as much as that of the low frequency band so as to reduce the gain fluctuation in the whole broadband; the single-pole double-throw switch is connected with the high-frequency band signal, the low-frequency band signal and the signal output port.

The circuit structure diagram of the present embodiment is shown in fig. 2, and a wideband low noise amplifier with a reconfigurable frequency band includes a wideband low noise amplifier stage, a coupling line termination inductor, a coupling line termination capacitor, a high-frequency amplifier, and a single-pole double-throw switch;

the broadband low-noise amplifier stage comprises two sub-amplifier stages with the same structure, and each sub-amplifier stage adopts an inductance peaking common-source and common-gate structure based on resistance negative feedback and inductive negative feedback; the first sub-amplification stage comprises transistors M1 and M2, a gate inductor Lg1, a source degeneration inductor Ls1, a source-drain intermediate inductor L1, a drain inductor Ld1, a feedback resistor Rf1, gate resistors Rg1 and Rg2, and blocking capacitors Cf1 and C1; the second sub-amplification stage consists of transistors M3 and M4, a gate inductor Lg2, a source degeneration inductor Ls2, a source-drain intermediate inductor L2, a drain inductor Ld2, a feedback resistor Rf2, gate resistors Rg3 and Rg4, and blocking capacitors Cf2 and C2, and the whole structure of the second sub-amplification stage is the same as that of the first sub-stage.

A gate of a first transistor M1 in the first sub-amplification stage is connected with one end of an inductor Lg1, one end of a capacitor Cf1 and one end of a resistor Rg1, a drain is connected with one end of the inductor L1, a source is connected with one end of an inductor Ls1, a source of a second transistor M2 is connected with the other end of the inductor L1, a gate is connected with one end of the resistor Rg2, and a drain is connected with one end of an inductor Ld1, one end of a resistor Rf1 and one end of a capacitor C1; the other end of the inductor Lg1 is used as an input end of a broadband input signal, the other end of the resistor Rg1 is connected with a first bias voltage Vbias1, and the other end of the resistor Rg2 is connected with a second bias voltage Vbias 2; the other end of the inductor Ld1 is connected with a power supply Vdd1, the other end of the inductor Ls1 is grounded, and the other end of the capacitor C1 is connected with one end of an inductor Lg2 in the second sub-amplification stage;

a gate of a third transistor M3 in the second sub-amplification stage is connected with the other end of an inductor Lg2, one end of a capacitor Cf2 and one end of a resistor Rg3, a drain is connected with one end of the inductor L2, a source is connected with one end of an inductor Ls2, a source of a fourth transistor M4 is connected with the other end of the inductor L2, a gate is connected with one end of the resistor Rg4, and a drain is connected with one end of an inductor Ld2, one end of a resistor Rf2 and one end of a capacitor C2; the other end of the resistor Rg3 is connected with a first bias voltage Vbias1, and the other end of the resistor Rg4 is connected with a second bias voltage Vbias 2; the other end of the inductor Ld2 is connected to the power supply Vdd1, the other end of the inductor Ls2 is grounded, and the other end of the capacitor C1 is connected to the input terminal 1 of the coupling line.

The transistors M1 and M2 and the inductors L1 and Ld1 in the first sub-amplifier stage form an inductor peaking cascode structure so as to ensure that the broadband low-noise amplifier stage has certain gain; a negative feedback network formed by the resistor Rf1 and the capacitor Cf1, a gate inductor Lg1 and a source degeneration inductor Ls1 jointly form an input matching network to complete radio frequency low-noise input matching; the gate resistors Rg1 and Rg2 are large resistors of kilo-ohm order, which prevent signal leakage to the bias power supply terminal, and the capacitor C1 is mainly used for dc blocking and inter-stage matching. The connections and functions between the elements of the second sub-amplifier stage are the same as those of the first sub-amplifier stage.

The coupled line ports include four ports 1, 2, 3 and 4. Port 1 is a broadband signal input end and is connected with the output end of the broadband low-noise amplifier stage (the other end of the capacitor C2); the port 2 is a through port, and is connected with one end of the terminating inductor Lc, one end of the terminating capacitor Cc1 and the first rotating end (the drain end of the transistor M11) of the single-pole double-throw switch, and mainly transmits low-frequency-band signals; port 3 is connected to one end of termination capacitor Cc2 and is an isolated port; the port 4 is a coupling terminal, which mainly transmits the coupled high-band signal and is connected to the input terminal (one terminal of the inductor Lg 3) of the high-band amplifier stage.

The line width of the coupling line determines the magnitude of a parasitic capacitance Cp1 between the coupling line and the ground, and the line width is proportional to Cp 1; the line spacing of the coupled lines determines the parasitic capacitance Cp2 between the coupled lines, which is inversely proportional to Cp 2. The coupling factor K of the coupled lines is related to Cp1 and Cp2 as follows:

signals enter from the input end of the coupling line, most high-frequency signals are coupled to the coupling end, the rest signals flow out from the straight-through end, and a small part of signals flow out from the coupling end. The voltage transmission equation of the signal from the input end to the coupling end is as follows:

where θ is the electrical length of the coupling line, which is the ratio of the mechanical length (or geometric length) of the transmission line to the wavelength of the electromagnetic waves transmitted on the line, C is the coupling transmission coefficient, j is an imaginary unit, Vin is the voltage signal input to the input terminal, and Vcoupled is the voltage signal flowing out from the coupling terminal. The voltage transmission equation of the signal from the input end to the through end is as follows:

where T is a through transfer coefficient, vthregh is a voltage signal output from the through terminal. The voltage transmission equation of the signals from the input end to the coupling end and the straight-through end is adjusted by adjusting the line width, the length and the line spacing of the coupling line, so that the frequency range of the signals flowing out of the coupling end and the straight-through end is changed.

Since the reactance of the capacitor is inversely proportional to the frequency, the reactance of Cc1 and Cc2 is very small at high frequencies. After bypass capacitors Cc1 and Cc2 are respectively added to the through end and the isolation end of the coupling line, the through end and the isolation end of the coupling line are equivalent to short circuit to the ground at high frequency. At this time, the signal at the signal input end of the coupling line, a part of the high-frequency signal thereof is coupled to the coupling port, and the rest of the high-frequency signal and the low-frequency signal flow into the through port. For high-frequency signals, the straight-through end is short-circuited to the ground and is reflected, the reflected high-frequency signals are coupled to the isolation end, and the high-frequency signals are reflected again and finally flow out of the coupling section due to the fact that the isolation end is also short-circuited with the capacitor. As can be seen from the above process, the input signal can be divided into high-frequency and low-frequency signals by adding a bypass capacitor to the through terminal and the isolation terminal of the coupling line to reflect the high-frequency signal. Increasing the capacitance of Cc1 and Cc2, the demarcation point between the high and low frequency signals will shift toward the low frequency.

In summary, by adjusting the line width, length, line spacing of the coupling line, and the values of the capacitors Cc1 and Cc2, the frequency ranges of signals that are directly transmitted from the 2-port and the 4-port and are coupled out from the 1-port can be adjusted, and frequency band reconstruction is achieved.

The high-frequency band amplification stage provides certain gain for the high-frequency band signal, so that the gain of the high-frequency band is consistent with that of the low-frequency band after the signal passes through the high-frequency band amplification stage, and the gain fluctuation between the balanced high-frequency band signal and the low-frequency band signal is formed by two sub-amplification stages. The first sub-amplification stage consists of transistors M5 and M6, inductors Lg3, Ls3, L3 and Ld3, resistors Rf3, Rg5 and Rg6 and a capacitor Cf3, and the whole structure of the first sub-amplification stage is the same as that of the first sub-amplification stage of the broadband low-noise amplification stage. The second sub-amplification stage consists of a transistor M5, an inductor Ld4, a capacitor Cf4, a resistor Rf4 and an Rg7, and a negative feedback network of the resistor Rf4 and the capacitor Cf4 is combined with the load inductor Ld4 and the common-source transistor M5 to amplify the broadband signal.

A gate of the fifth transistor M5 in the first sub-amplification stage is connected to one end of an inductor Lg3, one end of a capacitor Cf3 and one end of a resistor Rg5, a drain is connected to one end of an inductor L3, and a source is connected to one end of an inductor Ls 3; the source of the sixth transistor M6 is connected to the other end of the inductor L3, the gate is connected to one end of the resistor Rg5, and the drain is connected to one end of the inductor Ld3, one end of the resistor Rf3, and one end of the capacitor C3; the other end of the inductor Lg3 is used as an input end of a high-frequency-band signal, the other end of the resistor Rg5 is connected with a first bias voltage Vbias1, and the other end of the resistor Rg6 is connected with a second bias voltage Vbias 2; the other end of the inductor Ld3 is connected with an input power supply Vdd1, the other end of the inductor Ls3 is grounded, and the other end of the capacitor C3 is connected with the gate of a seventh transistor M7 in the second sub-amplification stage;

the gate of a seventh transistor M7 in the second sub-amplifier stage is connected to the other end of the capacitor C3, one end of the resistor Rg7 and one end of the capacitor Cf4 in the first sub-amplifier stage, the source is grounded, the drain is connected to one end of the capacitor C4, one end of the resistor Rf4 and one end of the inductor Ld4, the other end of the resistor Rf4 is connected to the other end of the capacitor Cf4, the other end of the inductor Ld4 is connected to the power supply Vdd2, and the other end of the capacitor C4 is connected to the second rotation end of the single-pole double-throw switch.

Compared with the high-frequency-band signal coupled out from the port 4, the low-frequency-band signal directly communicated from the port of the coupling line 2 has higher gain, so that a low-frequency-band amplifier stage is not arranged, and the signal is directly connected with the first rotating end of the single-pole double-throw switch.

The two rotation ends of the single-pole double-throw switch are respectively connected with the output end (the other end of the capacitor C4) of the high-frequency-band amplifier stage and the through end 2 of the coupling line, and the single-pole double-throw switch consists of four transistors M8, M9, M10 and M11, a matching inductor L4, gate resistors Rg8, Rg9, Rg10 and Rg 11. The gate of the eighth transistor M8 is connected to one end of the gate resistor Rg8, the source is connected to the other end of the capacitor C4 and the source of the tenth transistor M10, and the drain is grounded; the gate of the ninth transistor M9 is connected to one end of the gate resistor Rg9, the source is grounded, and the drain is connected to the through end 2 of the coupling line and the drain of the eleventh transistor M11; the gate of the tenth transistor M10 is connected to one end of the gate resistor Rg10 and the other end of the gate resistor Rg9, and the drain is connected to one end of the matching inductor L4 and the source of the eleventh transistor M11; the gate of the eleventh transistor M11 is connected to the other end of the gate resistor Rg8 and one end of the gate resistor Rg11, the other end of the gate resistor Rg11 is connected to the voltage Vswith2, the other end of the gate resistor Rg10 is connected to the voltage Vswith1, and the other end of the matching inductor L4 is the output end of the wideband low noise amplifier.

The matching inductor L4 mainly plays a role of matching. When Vswitch1 is asserted high, Vswitch2 is asserted low, the branch with the high frequency band is turned on, and vice versa.

Example 2

If the gain of the low-frequency signal from the coupling line through terminal is smaller than that of the high-frequency signal after the signal is amplified by the broadband low-noise amplifier stage, a low-frequency amplifier stage can be added between the single-pole double-throw switch and the coupling line structure to reduce the gain fluctuation, and the schematic diagram of the architecture is shown in fig. 3.

The low-frequency-band signal is input to the low-frequency-band amplifier stage through the straight-through end of the coupling line, the circuit structure of the low-frequency-band amplifier stage can be the same as that of the high-frequency amplifier stage, and the high-frequency-band signal output by the high-frequency-band amplifier stage of the low-frequency-band signal amplified and output by the low-frequency-band amplifier stage is output through selection of the single-pole double-throw switch.

Fig. 4 and 5 are a reconstructed noise diagram and a reconstructed gain performance diagram, which are implemented by the circuit structure shown in fig. 2 based on a GaAs process in embodiment 1 of the present invention, where a full frequency band implemented by the circuit is 2-18GHz, a bandwidth is 16GHz, and reconstructed frequency bands are a 2-5GHz low frequency band and a 5-18GHz high frequency band, respectively. In fig. 4, the dotted line is a noise curve of a low frequency band, the noise of 2-5GHz is 1dB, the solid line is a noise curve of a high frequency band, and the noise of 5-18GHz is 1.1-1.2dB, and it can be seen from the figure that the noise in a wide frequency band range of 2-18GHz after reconstruction is 1-1.2dB, and very excellent noise performance is realized. In fig. 5, the dotted line is a gain curve of a low frequency band, the gain of 2-5GHz is 24-25dB, the solid line is a gain curve of a high frequency band, and the gain of 5-18GHz is 24-26dB, so that it can be seen that the gain in a broadband range of 2-18GHz after reconstruction is 24-26dB, and the characteristics of high gain and good flatness are provided. In general, the frequency band reconfigurable low-noise amplifier has the advantages of wide bandwidth, low noise, high gain, good gain flatness and good flexibility, and has good practical value.

While the invention has been described with reference to specific embodiments, any feature disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise; all of the disclosed features, or all of the method or process steps, may be combined in any combination, except mutually exclusive features and/or steps.