Multi-coupling broadband radio frequency low-noise amplifier

Abstract

The invention discloses a multi-coupling broadband radio frequency low-noise amplifier, relates to a semiconductor integrated circuit, and provides the scheme aiming at the problems that the gain is difficult to improve and the like in the prior art. Comprising an input matching network, a first-stage amplifying circuit, a second-stage amplifying circuit, a third capacitor, a third-stage amplifying circuit, a fourth-stage amplifying circuit and an output matching network which are in signal connection in sequence. Each stage of amplifying circuit is respectively matched with a corresponding grid bias network and a drain bias network; the input end of the first-stage amplifying circuit is formed by a gate-source coupling feedback structure; the output end of the second-stage amplification circuit, the third capacitor and the input end of the third-stage amplification circuit jointly form a magnetoelectric parallel coupling structure to serve as an inter-stage matching network; and the output end of the third-stage amplifying circuit is formed by a drain-source coupling feedback structure. The low-noise amplifier has the advantages that the bandwidth of the amplifier is expanded and the performance of the low-noise amplifier is improved by using the coupling connecting lines in the specified circuit modules respectively.

Description

Technical Field

[0001] The invention relates to a semiconductor integrated circuit applied to radio frequency technology, and in particular to a multi-coupled broadband radio frequency low noise amplifier. Background Art

[0002] Wideband low-noise amplifiers can operate over a wider frequency range to meet the needs of multiple spectrums, avoid frequent switching and adjustment of amplifier design, simplify system architecture, and provide consistent performance in multiple frequency bands, so that the system does not need to design a separate amplifier for each frequency band, effectively reducing the number of components in the system and achieving a more compact and lower-cost design.

[0003] The design of broadband low-noise amplifiers faces many technical challenges, especially in terms of noise control and gain balance. In order to achieve bandwidth expansion, the technologies adopted in recent years include resistive feedback, zero-pole control, etc., but broadband inevitably brings about increased loss and decreased gain. At the same time, in low-noise amplifiers, it is difficult to achieve broadband noise matching and input matching at the same time, and it is difficult to optimize the input reflection coefficient and noise coefficient at the same time. In addition, broadband matching networks often find it difficult to balance low noise and large bandwidth, and will lead to a decrease in gain. Limited by the maximum gain of the transistor, the gain at the high-frequency end of the band is often difficult to increase.

[0004] The technical solutions disclosed in the prior art include "a single-stage low noise amplifier with coupled line feedback" CN114598271A, but the single-stage amplifier is still very limited in actual circuit applications and it is difficult to meet the high-demand technical environment. For example, its 3dB operating bandwidth is relatively narrow. Summary of the invention

[0005] The object of the present invention is to provide a multi-coupled broadband radio frequency low noise amplifier to solve the problems existing in the above-mentioned prior art.

[0006] The multi-coupled broadband radio frequency low noise amplifier described in the present invention comprises an input matching network, a first-stage amplifying circuit, a second-stage amplifying circuit, a third capacitor, a third-stage amplifying circuit, a fourth-stage amplifying circuit and an output matching network which are sequentially connected in signal connection; each stage of the amplifying circuit is matched with a corresponding gate bias network and a drain bias network respectively; in, The first-stage amplifier circuit forms an input terminal with a gate-source coupled feedback structure; The transmission line at the output end of the second-stage amplifier circuit, the third capacitor, and the transmission line at the input end of the third-stage amplifier circuit together form a magneto-electric parallel coupling structure to serve as an inter-stage matching network; The third-stage amplifier circuit forms an output terminal with a drain-source coupling feedback structure.

[0007] The multi-coupled broadband radio frequency low noise amplifier described in the present invention has the advantage that by using coupling connecting lines in designated circuit modules respectively, the bandwidth of the amplifier is extended and the performance of the low noise amplifier is improved. In the first-stage amplifier circuit, gate-source coupling feedback is introduced to reduce the gap between the conjugate of the optimal noise source impedance in the wide band and the input impedance, thereby achieving coordinated matching of broadband noise and input reflection. Introducing magneto-electric parallel coupling in the second and third-stage amplifier circuits and the third capacitor can extend the matching bandwidth while avoiding the increase in loss as much as possible. Introducing drain-source coupling feedback in the third-stage amplifier circuit improves high-frequency gain and adjusts the gain characteristics in the broadband, thereby expanding the 3dB operating bandwidth. In addition, by connecting a transmission line in series with the drain of each stage of the transistor, the gain of the transistor becomes gentle with the frequency roll-off, thereby improving the gain flatness. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram of the framework structure of a multi-coupled broadband radio frequency low noise amplifier described in the present invention.

[0009] Figure 2 It is a schematic diagram of the circuit principle of a multi-coupled broadband radio frequency low noise amplifier described in the present invention.

[0010] Figure 3 It is an S parameter simulation curve diagram of a multi-coupled broadband radio frequency low noise amplifier described in the present invention.

[0011] Figure 4 It is a noise coefficient simulation curve diagram of a multi-coupled broadband radio frequency low noise amplifier described in the present invention.

[0012] Reference numerals: RFin-RF input terminal, RFout-RF output terminal; C1 to C6: first capacitor to sixth capacitor; Cf-feedback capacitor, Rf-feedback resistor; M1 to M4: first to fourth transistors; TL01 to TL12: the first transmission line to the twelfth transmission line; VG-gate bias voltage, VD-drain bias voltage. DETAILED DESCRIPTION

[0013] The structure of the multi-coupled broadband radio frequency low noise amplifier described in the present invention is as follows: Figure 1As shown, it includes an input matching network, a first-stage amplifier circuit, a second-stage amplifier circuit, a third capacitor C3, a third-stage amplifier circuit, a fourth-stage amplifier circuit and an output matching network that are sequentially connected. Each stage amplifier circuit is matched with a corresponding gate bias network and a drain bias network. Among them, the first-stage amplifier circuit forms an input end with a gate-source coupling feedback structure. The transmission line at the output end of the second-stage amplifier circuit, the third capacitor C3 and the transmission line at the input end of the third-stage amplifier circuit together constitute a magnetoelectric parallel coupling structure to serve as an inter-stage matching network. The third-stage amplifier circuit forms an output end with a drain-source coupling feedback structure. Each bias network uses a known structure in the prior art.

[0014] The circuit principle of the multi-coupled broadband radio frequency low noise amplifier described in the present invention is as follows: Figure 2 As shown, the input matching network is composed of a first capacitor C1, a first plate of the first capacitor C1 is connected to the radio frequency input terminal Rfin, and a second plate is connected to the first transmission line TL01 of the first stage amplifier circuit.

[0015] The specific structure of the first-stage amplifier circuit is as follows: the gate of the first transistor M1 is connected to the input matching network through the first transmission line TL01, and is connected to the gate bias voltage VG through the first gate bias network. After the drain of the first transistor M1 is connected in series with the third transmission line TL03, it is respectively connected to the second capacitor C2 of the second-stage amplifier circuit, and is connected to the drain bias voltage VD through the first drain bias network. The source of the first transistor M1 is connected in series with the second transmission line TL02 and then grounded. The first transmission line TL01 and the second transmission line TL02 are magnetically coupled to form the gate-source coupling feedback structure. After the gate-source coupling, the real part of the optimal noise source impedance remains basically unchanged, the imaginary part increases, and the real part of the input impedance decreases. By controlling the size of the feedback amount, the input impedance and the conjugate of the optimal noise source impedance can be made nearly equal at the operating frequency. Therefore, when designing the matching network, the two can be moved to the vicinity of 50Ω along the same trajectory to achieve the coordinated optimization of the noise coefficient and input matching.

[0016] The specific structure of the second-stage amplifier circuit is as follows: the gate of the second transistor M2 is connected to the third transmission line TL03 of the first-stage amplifier circuit through the second capacitor C2, and is connected to the gate bias voltage VG through the second gate bias network. The drain of the second transistor M2 is connected in series with the fourth transmission line TL04, and is connected to the third capacitor C3, and is connected to the drain bias voltage VD through the sixth transmission line TL06 and the second drain bias network in sequence. The source of the second transistor M2 is connected in series with the fifth transmission line TL05 and then grounded. The sixth transmission line TL06 is magnetically coupled with the seventh transmission line TL07 of the third-stage amplifier circuit, and the third capacitor C3 is used to provide an electrical coupling channel for the output end of the second-stage amplifier circuit and the input end of the third amplifier circuit, together forming the magneto-electric parallel coupling structure. Magnetic coupling and electrical coupling transmit signals simultaneously, and the two complement each other to solve the problems of large insertion loss of coupling lines and narrow capacitance bandwidth, achieving bandwidth expansion while minimizing the introduction of loss and noise.

[0017] The first plate of the third capacitor C3 is connected to the fourth transmission line TL04 of the second-stage amplifier circuit, and the second plate is connected to the seventh transmission line TL07 of the third-stage amplifier circuit.

[0018] The specific structure of the third-stage amplifier circuit is as follows: the gate of the third transistor M3 is connected to the third capacitor C3 respectively, and is connected to the gate bias voltage VG after passing through the seventh transmission line TL07 and the third gate bias network in sequence. The drain of the third transistor M3 is connected to the fourth capacitor C4 of the fourth-stage amplifier circuit through the eighth transmission line TL08 respectively, and is connected to the drain bias voltage VD after passing through the tenth transmission line TL10 and the third drain bias network in sequence. The source of the third transistor M3 is grounded after passing through the ninth transmission line TL09. The ninth transmission line TL09 is magnetically coupled with the tenth transmission line TL10 to form the drain-source coupling feedback structure. The drain-source coupling feedback can construct an additional signal path to couple part of the output signal to the input loop, thereby enhancing the signal amplification capability of the amplifier unit at this stage. The gain of the third transistor M3 decreases with the increase of frequency, while the coupling coefficient of the coupling structure increases with the increase of frequency. Therefore, the higher the frequency, the stronger the gain enhancement effect, thereby adjusting the gain characteristics within the broadband and expanding the 3dB working bandwidth.

[0019] The specific structure of the fourth-stage amplifier circuit is as follows: the gate of the fourth transistor M4 is connected to three branches, the first branch is connected to the eighth transmission line TL08 of the third-stage amplifier circuit through the fourth capacitor C4, the second branch is connected to the gate bias voltage VG through the fourth gate bias network, and the third branch is connected to the fifth capacitor C5 of the output matching network after the feedback resistor Rf and the feedback capacitor Cf are connected in series. The drain of the fourth transistor M4 is connected to the output matching network after passing through the eleventh transmission line TL11, and is connected to the drain bias voltage VD through the fourth drain bias network. The source of the fourth transistor M4 is grounded after passing through the twelfth transmission line TL12. The fourth-stage amplifier circuit adds RC negative feedback on the basis of the common source amplifier structure to balance the unevenness of the gains of each stage, so that the gain is flatter in a wide band and the 3dB bandwidth is further extended.

[0020] The output matching network is composed of a fifth capacitor C5, a first plate of the fifth capacitor C5 is connected to the eleventh transmission line TL11 of the fourth-stage amplifier circuit, and a second plate is connected to the radio frequency output terminal Rfout.

[0021] The multi-coupled broadband RF low-noise amplifier described in the present invention has a transmission line connected in series at the drain of each stage of the transistor, which slows down the roll-off of the transistor's gain with frequency, improves the gain flatness, and improves the consistency of the gain curve within the broadband. The coordinated cooperation of the various module units enables the overall technical solution to work in a wider frequency range, thereby meeting the needs of multiple spectrums, avoiding frequent switching and adjustment of amplifier design, and simplifying the system architecture. It can also provide consistent performance in multiple frequency bands, so that the system does not need to design a separate amplifier for each frequency band, effectively reducing the number of components in the system and achieving a more compact and lower-cost design.

[0022] The technical effect of the multi-coupled broadband radio frequency low noise amplifier described in the present invention is as follows: Figure 3 and Figure 4 shown. Figure 3 The S parameter simulation result of the low noise amplifier in the present invention shows that the 3dB operating bandwidth is 21.9-33.6GHz and the relative bandwidth is 42.2%. It is generally believed that an amplifier with a 3dB bandwidth of more than 30% is a broadband amplifier, and the 3dB operating bandwidth of the low noise amplifier in the present invention meets the standard of a broadband amplifier, and the in-band gain is relatively flat, and the input and output reflection coefficients are low. Figure 4 The noise coefficient simulation result of the low noise amplifier in the present invention shows that the noise coefficient is 1.7-2.6dB within the 3dB working bandwidth. Generally speaking, the noise coefficient of the low noise amplifier in this frequency band is generally 2-3dB. The low noise amplifier in the present invention achieves a lower noise coefficient level.

[0023] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A multi-coupled broadband radio frequency low noise amplifier, characterized in that: It includes an input matching network, a first-stage amplifier circuit, a second-stage amplifier circuit, a third capacitor (C3), a third-stage amplifier circuit, a fourth-stage amplifier circuit and an output matching network which are sequentially connected; each stage amplifier circuit is matched with a corresponding gate bias network and a drain bias network; in, The first-stage amplifier circuit forms an input terminal with a gate-source coupled feedback structure; The transmission line at the output end of the second-stage amplifier circuit, the third capacitor (C3) and the transmission line at the input end of the third-stage amplifier circuit together form a magneto-electric parallel coupling structure to serve as an inter-stage matching network; The third-stage amplifier circuit forms an output terminal with a drain-source coupling feedback structure.

2. The multi-coupled broadband radio frequency low noise amplifier according to claim 1, characterized in that: The input matching network is composed of a first capacitor (C1), wherein a first plate of the first capacitor (C1) is connected to a radio frequency input terminal (RFin), and a second plate is connected to an input terminal of the first-stage amplifier circuit.

3. The multi-coupled broadband radio frequency low noise amplifier according to claim 1, characterized in that: The specific structure of the first-stage amplifier circuit is: The gate of the first transistor (M1) is connected to the input matching network through a first transmission line (TL01), and is connected to a gate bias voltage (VG) through a first gate bias network; The first transistor (M1) is connected to the third transmission line (TL03) in series, and is respectively connected to the input end of the second stage amplifier circuit, and is connected to the drain bias voltage (VD) through the first drain bias network; The source of the first transistor (M1) is connected in series with the second transmission line (TL02) and then grounded; The first transmission line (TL01) and the second transmission line (TL02) are magnetically coupled to form the gate-source coupled feedback structure.

4. The multi-coupled broadband radio frequency low noise amplifier according to claim 1, characterized in that: The specific structure of the second-stage amplifier circuit is: The gate of the second transistor (M2) is connected to the output end of the first-stage amplifier circuit through a second capacitor (C2), and is connected to a gate bias voltage (VG) through a second gate bias network; The drain of the second transistor (M2) is connected in series with the fourth transmission line (TL04), and then connected to the third capacitor (C3), and then connected to the drain bias voltage (VD) through the sixth transmission line (TL06) and the second drain bias network in sequence; The source of the second transistor (M2) is connected in series with the fifth transmission line (TL05) and then grounded; The sixth transmission line (TL06) is magnetically coupled to the transmission line at the input end of the third-stage amplifier circuit, and is electrically coupled to the third-stage amplifier circuit through the third capacitor (C3).

5. The multi-coupled broadband radio frequency low noise amplifier according to claim 1, characterized in that: The first plate of the third capacitor (C3) is connected to the output end of the second-stage amplifier circuit, and the second plate is connected to the input end of the third-stage amplifier circuit; the third capacitor (C3) is used to provide an electrical coupling channel between the output end of the second-stage amplifier circuit and the input end of the third amplifier circuit.

6. The multi-coupled broadband radio frequency low noise amplifier according to claim 1, characterized in that: The specific structure of the third-stage amplifier circuit is: The gate of the third transistor (M3) is respectively connected to the third capacitor (C3), and is connected to the gate bias voltage (VG) through the seventh transmission line (TL07) and the third gate bias network in sequence; The drain of the third transistor (M3) is connected to the input end of the fourth stage amplifier circuit through the eighth transmission line (TL08), and is connected to the drain bias voltage (VD) through the tenth transmission line (TL10) and the third drain bias network in sequence; The source of the third transistor (M3) is grounded after passing through the ninth transmission line (TL09); The ninth transmission line (TL09) is magnetically coupled with the tenth transmission line (TL10) to form the drain-source coupling feedback structure; The seventh transmission line (TL07) is magnetically coupled to the transmission line at the output end of the second-stage amplifier circuit, and is electrically coupled to the second-stage amplifier circuit through the third capacitor (C3).

7. The multi-coupled broadband radio frequency low noise amplifier according to claim 1, characterized in that: The specific structure of the fourth-stage amplifier circuit is: The gate of the fourth transistor (M4) is connected to three branches, the first branch is connected to the output end of the third-stage amplifier circuit through a fourth capacitor (C4), the second branch is connected to the gate bias voltage (VG) through a fourth gate bias network, and the third branch is connected to the output matching network after being connected in series with a feedback resistor (Rf) and a feedback capacitor (Cf); The drain of the fourth transistor (M4) is respectively connected to the output matching network after passing through the eleventh transmission line (TL11), and is connected to the drain bias voltage (VD) through the fourth drain bias network; The source of the fourth transistor (M4) is grounded through the twelfth transmission line (TL12).

8. The multi-coupled broadband radio frequency low noise amplifier according to claim 1, characterized in that: The output matching network is composed of a fifth capacitor (C5), a first plate of the fifth capacitor (C5) is connected to the output end of the fourth-stage amplifier circuit, and a second plate is connected to the radio frequency output end (Rfout).

Images