An integrated filtered balanced low-noise amplifier

Abstract

This invention discloses an integrated filtered balanced low-noise amplifier, comprising a bandpass filter input matching circuit, a differential amplifier circuit, and a bandpass filter output matching circuit connected in sequence. The input of the bandpass filter input matching circuit is connected to a radio frequency (RF) signal, and its output is connected to the differential amplifier circuit. The differential amplifier circuit amplifies the RF signal and outputs it through the two ports of the bandpass filter output matching circuit. Both the bandpass filter input matching circuit and the bandpass filter output matching circuit serve to match the impedance of the differential amplifier circuit and also possess the frequency selection characteristics of a bandpass filter, filtering out out-of-band interference signals. The differential amplifier circuit overcomes the influence of bias potential. This invention improves the common-mode noise suppression performance and out-of-band interference immunity of the low-noise amplifier, and expands the amplifier's operating bandwidth.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, and specifically relates to an integrated filtered balanced low-noise amplifier. Background Technology

[0002] Currently, with the rapid development of wireless communication systems, the requirements for radio frequency (RF) front-end receivers are becoming increasingly stringent. Low-noise amplifiers (LNOA) and filters, as key components of RF front-end receivers, determine the performance of wireless communication systems. The LNOA, as the first stage of active circuitry in the receiver, is primarily responsible for amplifying the weak signals received by the RF antenna. It also needs to achieve low noise figure, high gain, and high linearity over a wide frequency range. The noise figure of the LNOA determines the overall noise of the entire receiver link; to suppress the impact of noise on subsequent circuits, the amplifier must have a sufficiently low noise figure. Filters are typically located before and after the LNOA, and are cascaded directly with the LNOA to filter out interference signals in the frequency band.

[0003] Achieving low noise figure, good impedance matching, and good gain response over a wide bandwidth is extremely challenging, making broadband low-noise amplifiers a hot research topic. Common-source, common-gate, negative feedback, and multi-stage cascaded topologies are all commonly used. Common-source amplifiers are widely used due to their low noise figure, but their bandwidth is narrow, failing to meet broadband requirements. Negative feedback is commonly used in amplifier circuits to extend the amplifier's operating bandwidth and improve the flatness of the gain response. Therefore, adding negative feedback to a common-source amplifier structure creates a negative feedback common-source amplifier. This topology overcomes the narrow-band applicability of common-source amplifiers and is currently the topology used in most broadband low-noise amplifiers. However, the addition of negative feedback can worsen the noise of the common-source amplifier circuit, requiring a trade-off between bandwidth and noise figure. Common-gate amplifiers can achieve controllable input impedance by adjusting the physical dimensions of the amplifier transistors to obtain a suitable transconductance value. Therefore, this structure can achieve good broadband input matching performance. The drawback of common-gate amplifier structures is their relatively high noise figure. In practical circuits, using this structure requires additional noise reduction techniques, such as noise cancellation and equivalent transconductance enhancement, which increases circuit complexity. Cascaded amplifier structures, formed by connecting multiple single-stage amplifier circuits in series, offer high gain and good stability. The noise figure of a cascaded amplifier structure primarily depends on the noise figure of the first stage amplifier circuit; therefore, the noise performance of the first stage circuit must be sufficiently good. Due to the interstage matching network in the cascaded configuration, impedance mismatch is unavoidable, leading to higher insertion loss. Furthermore, achieving a flat, low noise figure across a wide bandwidth is difficult using a multi-stage cascaded approach.

[0004] Currently, most low-noise amplifiers adopt a single-ended input and single-ended output structure. They all share a common problem: in broadband mode, single-ended low-noise amplifiers are susceptible to environmental noise and out-of-band signal interference, which reduces the performance of the receiving system. Summary of the Invention

[0005] To overcome the problems existing in the above-mentioned technologies, this invention provides an integrated filtered balanced low-noise amplifier. It improves the common-mode noise suppression performance and out-of-band interference immunity of the low-noise amplifier, and extends the amplifier's operating bandwidth. This structure combines the bandpass filter with the matching circuit of the low-noise amplifier, achieving a fusion of matching and filtering functions. Due to the symmetry of the balanced structure and the complex impedance transformation characteristics, the differential low-noise amplifier possesses common-mode noise suppression and attenuated differential-mode signal transmission characteristics, while also exhibiting good broadband and filtering characteristics.

[0006] The technical solution includes a bandpass filter input matching circuit, a differential amplifier circuit, and a bandpass filter output matching circuit connected in sequence.

[0007] The input of the bandpass filter input matching circuit is connected to the radio frequency signal, and the output is connected to the differential amplifier circuit. The differential amplifier circuit amplifies the radio frequency signal and outputs it through the two ports of the bandpass filter output matching circuit.

[0008] The bandpass filter input matching circuit and the bandpass filter output matching circuit not only serve to match the impedance of the differential amplifier circuit, but also possess the frequency selection characteristics of a bandpass filter to filter out out-of-band interference signals; the differential amplifier circuit overcomes the influence of bias potential.

[0009] Preferably, the bandpass filter input matching circuit is a vertically symmetrical ring stub loading matching network, comprising four symmetrical input T-shaped stub lines and two vertically symmetrical input cascaded main transmission lines.

[0010] Preferably, the input T-shaped branch line includes a first T-shaped branch line Ts1, a second T-shaped branch line Ts2, a third T-shaped branch line Ts3, and a fourth T-shaped branch line Ts4; wherein, one end of the first T-shaped branch line Ts1 is connected to one end of the second T-shaped branch line Ts2, and one end of the third T-shaped branch line Ts3 is connected to one end of the fourth T-shaped branch line Ts4.

[0011] Preferably, the input cascaded main transmission line includes a seventh transmission line TL7, an eighth transmission line TL8, a ninth transmission line TL9, and a tenth transmission line TL10; wherein, the seventh transmission line TL7 is connected to the eighth transmission line TL8, and is respectively connected to one end of the first T-shaped stub Ts1 and one end of the second T-shaped stub Ts2; the ninth transmission line TL9 is connected to the tenth transmission line TL10, and is respectively connected to one end of the third T-shaped stub Ts3 and one end of the fourth T-shaped stub Ts4.

[0012] Preferably, the differential amplifier circuit consists of two symmetrical amplifier circuits, including a first amplifier circuit and a second amplifier circuit.

[0013] Preferably, the first amplifier circuit includes a first common-source amplifier circuit, a first bias circuit, a first stabilizing circuit, a first capacitor C1, and a seventh capacitor C7.

[0014] The first common-source amplifier circuit includes a first transistor T1, a first inductor L1, a second inductor L2, a fifth capacitor C5, and a sixth capacitor C6. One end of the first inductor L1 is connected to the gate of the first transistor T1 to prevent radio frequency signals from leaking into the bias circuit; the other end is connected to the fifth capacitor C5 to short-circuit the leaked AC signal to ground, reducing its impact on the bias circuit. One end of the second inductor L2 is connected to the drain of the first transistor T1 to prevent radio frequency signals from leaking into the bias circuit; the other end is connected to the sixth capacitor C6 to short-circuit the leaked AC signal to ground, reducing its impact on the bias circuit. The first bias circuit includes a first resistor R1, a second resistor R2, a third resistor R3, and multiple bypass capacitors. The two ends of the second resistor R2 are connected to the first resistor R1 and the third resistor R3 respectively, forming a resistive voltage divider structure. Therefore, a single power supply can be used to provide a suitable bias point for the gate and drain of the first transistor T1. The third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are connected in parallel to short-circuit the AC signal from the DC power supply to ground, preventing interference signals from entering the RF path. The first stabilization circuit is composed of the seventeenth transmission line.

[0015] Preferably, the second amplifier circuit is structurally symmetrical to the first amplifier circuit, and the device parameters used are the same.

[0016] Preferably, the bandpass filter output matching circuit is a top-and-bottom symmetrical ring stub loading matching network, which includes four symmetrical output T-shaped stub lines and two top-and-bottom symmetrical output cascaded main transmission lines.

[0017] Preferably, the output T-shaped branch line includes a fifth T-shaped branch line Ts5, a sixth T-shaped branch line Ts6, a seventh T-shaped branch line Ts7, and an eighth T-shaped branch line Ts8; wherein one end of the fifth T-shaped branch line Ts5 is connected to one end of the sixth T-shaped branch line Ts6; and one end of the seventh T-shaped branch line Ts7 is connected to one end of the eighth T-shaped branch line Ts8.

[0018] Preferably, the output cascaded main transmission line includes the twenty-fifth transmission line TL25, the twenty-sixth transmission line TL26, the twenty-seventh transmission line TL27, and the twenty-eighth transmission line TL28.

[0019] Specifically, the 25th transmission line TL25 and the 26th transmission line TL26 are connected to form a stepped impedance transformer, and are respectively connected to one end of the fifth T-shaped stub Ts5 and one end of the seventh T-shaped stub Ts7; the 27th transmission line TL27 and the 28th transmission line TL28 are connected to form a stepped impedance transformer, and are respectively connected to one end of the sixth T-shaped stub Ts6 and one end of the eighth T-shaped stub Ts8.

[0020] The beneficial effects of the present invention include at least the following:

[0021] (1) The present invention adopts a method of combined design of filtering and impedance matching, which integrates the function of external independent filter into the low noise amplifier circuit, thereby reducing loss and reducing the size of receiver circuit.

[0022] (2) The present invention uses a differential amplification structure to eliminate the influence of bias potential fluctuations, so that the performance of the low noise amplifier remains stable.

[0023] (3) By adjusting the physical dimensions of the T-shaped stub line of the novel balanced bandpass filter matching network, the frequency conversion function is realized; at the same time, the in-band common mode rejection and out-of-band differential mode rejection performance are enhanced.

[0024] (4) The low-noise amplifier of the present invention uses differential pairs and balanced symmetrical matching networks for both input and output, which can cancel some nonlinear components in the radio frequency signal through the symmetrical structure, thereby improving the linearity of the circuit.

[0025] (5) The low-noise amplifier circuit structure of the present invention can achieve good input / output matching over a wide bandwidth while achieving low noise. Attached Figure Description

[0026] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0027] Figure 1This is a structural block diagram of the integrated filtered balanced low-noise amplifier according to an embodiment of the present invention;

[0028] Figure 2 This is a circuit diagram of an integrated filtered balanced low-noise amplifier according to an embodiment of the present invention;

[0029] Figure 3 This is a balanced bandpass filter matching circuit diagram of the integrated balanced low-noise amplifier according to an embodiment of the present invention;

[0030] Figure 4 This is an equivalent circuit diagram of the matching circuit under differential-mode signal excitation in the integrated filtered balanced low-noise amplifier of this invention.

[0031] Figure 5 This is an equivalent circuit diagram of the matching circuit under common-mode signal excitation in the integrated filtered balanced low-noise amplifier according to an embodiment of the present invention.

[0032] Figure 6 This is a simulation result diagram of the S-parameters of the integrated filtered balanced low-noise amplifier according to an embodiment of the present invention;

[0033] Figure 7 This is a simulation result of the noise figure of the integrated filtered balanced low-noise amplifier according to an embodiment of the present invention. Detailed Implementation

[0034] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0035] See Figure 1-3 The diagram shows the integrated filter balanced low-noise amplifier structure block diagram, circuit schematic diagram, and balanced structure of the bandpass filter input / output matching circuit according to an embodiment of the present invention. It includes a bandpass filter input matching circuit 10, a differential amplifier circuit 20, and a bandpass filter output matching circuit 30 connected in sequence. The input of the bandpass filter input matching circuit 10 is connected to a radio frequency (RF) signal, and its output is connected to the differential amplifier circuit 20. The differential amplifier circuit 20 amplifies the RF signal and outputs it through the two ports of the bandpass filter output matching circuit 30. The bandpass filter input matching circuit 10 and the bandpass filter output matching circuit 30 not only provide impedance matching with the differential amplifier circuit 20 but also possess the frequency selection characteristics of a bandpass filter, filtering out out-of-band interference signals. The differential amplifier circuit 20 overcomes the influence of bias potential.

[0036] The bandpass filter input matching circuit 10 is a vertically symmetrical ring-shaped stub-loaded matching network, containing four symmetrical input T-shaped stub lines and two vertically symmetrical input cascaded main transmission lines. The input T-shaped stub lines include a first T-shaped stub line Ts1, a second T-shaped stub line Ts2, a third T-shaped stub line Ts3, and a fourth T-shaped stub line Ts4; wherein, one end of the first T-shaped stub line Ts1 is connected to one end of the second T-shaped stub line Ts2, and one end of the third T-shaped stub line Ts3 is connected to one end of the fourth T-shaped stub line Ts4. The input cascaded main transmission line includes a seventh transmission line TL7, an eighth transmission line TL8, a ninth transmission line TL9, and a tenth transmission line TL10; wherein, the seventh transmission line TL7 is connected to the eighth transmission line TL8, and is connected to one end of the first T-shaped stub Ts1 and one end of the second T-shaped stub Ts2, respectively; the ninth transmission line TL9 is connected to the tenth transmission line TL10, and is connected to one end of the third T-shaped stub Ts3 and one end of the fourth T-shaped stub Ts4, respectively.

[0037] The differential amplifier circuit 20 consists of two symmetrical amplifier circuits, including a first amplifier circuit and a second amplifier circuit. The first amplifier circuit includes a first common-source amplifier circuit, a first bias circuit, a first stabilizing circuit, a first capacitor C1, and a seventh capacitor C7. The first common-source amplifier circuit includes a first transistor T1, a first inductor L1, a second inductor L2, a fifth capacitor C5, and a sixth capacitor C6. One end of the first inductor L1 is connected to the gate of the first transistor T1 to prevent radio frequency signals from leaking into the bias circuit; the other end is connected to the fifth capacitor C5 to short-circuit any leaked AC signals to ground, reducing the impact on the bias circuit. One end of the second inductor L2 is connected to the drain of the first transistor T1 to prevent radio frequency signals from leaking into the bias circuit; the other end... Connected to the sixth capacitor C6, the leaked AC signal is short-circuited to ground, reducing its impact on the bias circuit. The first bias circuit includes a first resistor R1, a second resistor R2, a third resistor R3, and multiple bypass capacitors. The two ends of the second resistor R2 are connected to the first resistor R1 and the third resistor R3 respectively, forming a resistive voltage divider structure. Therefore, a single power supply can be used to provide a suitable bias point for the gate and drain of the first transistor T1. The third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are connected in parallel to short-circuit the AC signal from the DC power supply to ground, preventing interference signals from entering the RF path. The first stabilization circuit is composed of the seventeenth transmission line. The second amplifier circuit is symmetrical in structure to the first amplifier circuit, and uses the same device parameters.

[0038] The bandpass filter output matching circuit 30 is a top-and-bottom symmetrical ring-shaped stub-loaded matching network, containing four symmetrical output T-shaped stub lines and two top-and-bottom symmetrical output cascaded main transmission lines. The output T-shaped stub lines include a fifth T-shaped stub line Ts5, a sixth T-shaped stub line Ts6, a seventh T-shaped stub line Ts7, and an eighth T-shaped stub line Ts8; one end of the fifth T-shaped stub line Ts5 is connected to one end of the sixth T-shaped stub line Ts6; and one end of the seventh T-shaped stub line Ts7 is connected to one end of the eighth T-shaped stub line Ts8. The output cascaded main transmission lines include the 25th transmission line TL25, the 26th transmission line TL26, the 27th transmission line TL27, and the 28th transmission line TL28. The 25th transmission line TL25 and the 26th transmission line TL26 are connected to form a stepped impedance transformer, and are respectively connected to one end of the fifth T-shaped stub Ts5 and one end of the seventh T-shaped stub Ts7. The 27th transmission line TL27 and the 28th transmission line TL28 are connected to form a stepped impedance transformer, and are respectively connected to one end of the sixth T-shaped stub Ts6 and one end of the eighth T-shaped stub Ts8.

[0039] In a specific embodiment, the operating frequency of this invention is 1.7GHz to 2.5GHz. Two differential ports, Port 1 and Port 2, are connected to the main transmission line as input terminals, and two other horizontally symmetrical differential ports, Port 3 and Port 4, serve as output terminals. The structure of the main transmission line remains the same for any frequency; the frequency conversion function of this matching network is achieved by the frequency selection stubs on the left and right sides.

[0040] Odd-pattern analysis:

[0041] When input port 1 is excited by a differential signal Figure 3 The horizontal line of symmetry shown corresponds to an ideal electric wall. For example... Figure 4 As shown, the odd-mode equivalent circuit of the balanced bandpass filter matching network is a π-type network. The impedance Z can be determined using the balanced structure symmetry analysis method. i The value of (i = 1, 2, 3). At a given frequency f. i Under (i=1,2), the input impedance Z Si (=R Si +j*X Si and output impedance Z Li (=R Li +j*X Li Assume that both are complex impedances. At frequency f1, let the impedance of the main transmission line be Z. Mk The electric length is θ Mk (k = 1, 2). The T-shaped stub used for frequency conversion is connected to the main circuit, with an impedance of Z. n (n=1,2,3,4,5,6), electric length is θ m(m = 1, 2, 3). At this point, all differential-mode signals should be transmitted to the output port without reflection, while common-mode signals should be totally reflected.

[0042] The transmission characteristics of the intermediate cascaded main transmission line in a π-type network can be represented by an ABCD transmission matrix.

[0043]

[0044] Z li and Z ri Let Z be the source impedance and load impedance at the left and right ends of the main transmission line, respectively. Assume the characteristic impedance and electrical length of the main transmission line are Z and Z', respectively. Mk and θ Mk (k=1,2), the equivalent input impedance of the T-shaped stub can be obtained as jX ai (jX bi The solution process is as follows:

[0045] Equations (2) and (3) are equations based on π-type multi-band impedance transformation:

[0046]

[0047]

[0048] So, the main transmission line Z li * and Z ri The impedance transformation between them satisfies the following equation:

[0049]

[0050] Through further mathematical transformations, X can ultimately be obtained. ai and X bi Relationship between them:

[0051] pX ai +rX ai X bi +qX bi =s (5)

[0052] The coefficients in formula (5) can be expressed as:

[0053] p1 = R Si D Mi R Li +X Si D Mi X Li +B Mi X Li (5-a-1)

[0054] r1 = A Mi XLi +B Mi -R Si C Mi R Li +X Si (D Mi -C Mi X Li ) (5-b-1)

[0055] q1=X Si (A Mi X Li +B Mi )+R Si R Li A Mi (5-c-1)

[0056] s1=-X Si B Mi X Li -R Si B Mi R Li (5-d-1)

[0057] p2=X Si D Mi R Li -R Si D Mi X Li +B Mi R Li (5-a-2)

[0058] r2=R Li A Mi -X Si C Mi R Li -R Si (D Mi -C Mi X Li ) (5-b-2)

[0059] q2=X Si R Li A Mi -R Si (A Mi X Li +B Mi ) (5-c-2)

[0060] s2=X Si B Mi R Li -X Si B Mi R Li (5-d-2)

[0061] Therefore, after determining the electrical parameters of the main transmission line and obtaining its ABCD matrix, while ensuring X... ai and X bi If (i = 1, 2) is a real root, then X can be accurately calculated using formula (5). ai and X bi The value of (i = 1, 2).

[0062] Even mode analysis:

[0063] When input port 1 is excited by a common-mode signal Figure 3 The horizontal line of symmetry shown corresponds to an ideal magnetic wall. See also Figure 5 The even-mode equivalent circuit of a balanced bandpass filter matching network is a π-type network. In this case, all common-mode signals should be transmitted to the output port without reflection, while differential-mode signals should be totally reflected. Similarly, using a symmetrical analysis method, the impedance values ​​of each transmission line can be obtained.

[0064] The parameters of each transmission line in the input / output matching network can be determined through the above method, ultimately achieving input / output impedance matching with transistors T1 and T2. The differential amplifier circuit in this embodiment employs a symmetrical common-source amplifier structure. One amplification path consists of transistor T1, transmission line TL17, inductors L1 and L2, and capacitors C1, C6, and C7. Capacitors C1 and C7 are used for DC blocking, while capacitor C6 short-circuits leaked AC signals to ground, reducing their impact on the bias circuit. Inductors L1 and L2 are used to prevent RF signals from leaking into the bias circuit. Transistor T1 is connected to transmission line TL17, increasing the real part of the input impedance and maintaining circuit stability. Three capacitors C3, C4, and C5 with different values ​​are connected to one end of VDD to short-circuit AC signals from the DC power supply, preventing interference signals from entering the RF path. The two ends of resistor R2 are connected to resistors R1 and R3 respectively, forming a resistive voltage divider structure, thus allowing a single power supply to provide a suitable bias point for the gate and drain of transistor T1. The other amplifier circuit has the same structure and device parameters as the amplifier circuit mentioned above.

[0065] See Figure 2 The equal-amplitude, inverted differential signals are input from both ends of the input matching network. After passing through the bandpass filter structure, the common-mode noise in the RF signal is reflected and lost, while the differential signal passes smoothly through the network into the two amplifier circuits. At this point, most of the common-mode noise is suppressed, improving the signal-to-noise ratio. The differential signal undergoes a phase flip at the output port of the amplifier circuit, with the two signals differing by 180°, and remains unchanged after passing through the bandpass output matching network.

[0066] Figure 6 and Figure 7Simulations of the S-parameters and noise figure for this embodiment are presented. The input / output return loss is less than -10dB, the gain is greater than 14.5dB, and the noise figure is less than 0.7dB in the 1.7–2.5GHz frequency band, achieving good bandpass filtering effect and noise suppression characteristics.

[0067] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. An integrated filtered balanced low-noise amplifier, characterized in that, It includes a bandpass filter input matching circuit, a differential amplifier circuit, and a bandpass filter output matching circuit connected in sequence, wherein, The input of the bandpass filter input matching circuit is connected to the radio frequency signal, and the output is connected to the differential amplifier circuit. The differential amplifier circuit amplifies the radio frequency signal and outputs it through the two ports of the bandpass filter output matching circuit. The bandpass filter input matching circuit and the bandpass filter output matching circuit not only serve to match the impedance of the differential amplifier circuit, but also possess the frequency selection characteristics of a bandpass filter to filter out out-of-band interference signals; the differential amplifier circuit overcomes the influence of bias potential. The bandpass filter input matching circuit is a top-and-bottom symmetrical ring stub loading matching network, which includes four symmetrical input T-shaped stub lines and two top-and-bottom symmetrical input cascaded main transmission lines. The input T-shaped branch line includes a first T-shaped branch line Ts1, a second T-shaped branch line Ts2, a third T-shaped branch line Ts3, and a fourth T-shaped branch line Ts4; wherein, one end of the first T-shaped branch line Ts1 is connected to one end of the second T-shaped branch line Ts2, and one end of the third T-shaped branch line Ts3 is connected to one end of the fourth T-shaped branch line Ts4; The differential amplifier circuit consists of two symmetrical amplifier circuits, including a first amplifier circuit and a second amplifier circuit.

2. The integrated filtered balanced low-noise amplifier according to claim 1, characterized in that, The input cascaded main transmission line includes a seventh transmission line TL7, an eighth transmission line TL8, a ninth transmission line TL9, and a tenth transmission line TL10; wherein, the seventh transmission line TL7 is connected to the eighth transmission line TL8, and is respectively connected to one end of the first T-shaped stub Ts1 and one end of the second T-shaped stub Ts2; the ninth transmission line TL9 is connected to the tenth transmission line TL10, and is respectively connected to one end of the third T-shaped stub Ts3 and one end of the fourth T-shaped stub Ts4.

3. The integrated filtered balanced low-noise amplifier according to claim 1, characterized in that, The first amplifier circuit includes a first common-source amplifier circuit, a first bias circuit, a first stabilizing circuit, a first capacitor C1, and a seventh capacitor C7. The first common-source amplifier circuit includes a first transistor T1, a first inductor L1, a second inductor L2, a fifth capacitor C5, and a sixth capacitor C6. One end of the first inductor L1 is connected to the gate of the first transistor T1 to prevent radio frequency signals from leaking into the bias circuit; the other end is connected to the fifth capacitor C5 to short-circuit the leaked AC signal to ground, reducing its impact on the bias circuit. One end of the second inductor L2 is connected to the drain of the first transistor T1 to prevent radio frequency signals from leaking into the bias circuit; the other end is connected to the sixth capacitor C6 to short-circuit the leaked AC signal to ground. To reduce the impact on the bias circuit, the first bias circuit includes a first resistor R1, a second resistor R2, a third resistor R3, and multiple bypass capacitors. The two ends of the second resistor R2 are connected to the first resistor R1 and the third resistor R3 respectively, forming a resistive voltage divider structure. Therefore, a single power supply can be used to provide a suitable bias point for the gate and drain of the first transistor T1. The third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are connected in parallel to short-circuit the AC signal from the DC power supply to ground, preventing interference signals from entering the RF path. The first stabilization circuit is composed of the seventeenth transmission line.

4. The integrated filtered balanced low-noise amplifier according to claim 3, characterized in that, The second amplifier circuit is symmetrical in structure to the first amplifier circuit, and the parameters of the components used are the same.

5. The integrated filtered balanced low-noise amplifier according to claim 1, characterized in that, The bandpass filter output matching circuit is a top-and-bottom symmetrical ring stub loading matching network, which includes four symmetrical output T-shaped stub lines and two top-and-bottom symmetrical output cascaded main transmission lines.

6. The integrated filtered balanced low-noise amplifier according to claim 5, characterized in that, The output T-shaped branch lines include a fifth T-shaped branch line Ts5, a sixth T-shaped branch line Ts6, a seventh T-shaped branch line Ts7, and an eighth T-shaped branch line Ts8; wherein one end of the fifth T-shaped branch line Ts5 is connected to one end of the sixth T-shaped branch line Ts6; and one end of the seventh T-shaped branch line Ts7 is connected to one end of the eighth T-shaped branch line Ts8.

7. The integrated filtered balanced low-noise amplifier according to claim 6, characterized in that, The output cascaded main transmission lines include the twenty-fifth transmission line TL25, the twenty-sixth transmission line TL26, the twenty-seventh transmission line TL27, and the twenty-eighth transmission line TL28. Specifically, the 25th transmission line TL25 and the 26th transmission line TL26 are connected to form a stepped impedance transformer, and are respectively connected to one end of the fifth T-shaped stub Ts5 and one end of the seventh T-shaped stub Ts7; the 27th transmission line TL27 and the 28th transmission line TL28 are connected to form a stepped impedance transformer, and are respectively connected to one end of the sixth T-shaped stub Ts6 and one end of the eighth T-shaped stub Ts8.

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