Millimeter wave broadband low-noise amplifier based on double-channel noise elimination

Abstract

The utility model discloses a millimeter wave broadband low-noise amplifier based on double-channel noise elimination. The millimeter wave broadband low-noise amplifier comprises a first-stage amplifier, an asymmetric output transformer, a second-stage amplifier and an output balun structure, the first-stage amplifier comprises a third transistor, a fourth transistor, a first inductor, a second inductor and a third inductor; the dotted terminal of the first inductor is connected with one end of the blocking capacitor, the other end of the first inductor is connected with the source electrode of the third transistor and the dotted terminal of the second inductor at the same time, the drain electrode of the third transistor serves as one output end of the first-stage amplifier, and the dotted terminal of the third inductor is connected with the grid electrode of the fourth transistor. The other end of the third inductor is connected with the grid electrode of the third transistor, the third inductor is provided with a center tap, and the drain electrode of the fourth transistor serves as the other output end of the first-stage amplifier. According to the utility model, the defect of additional phase mismatch caused by the adoption of an isolation capacitor is overcome, and transconductance enhancement and noise elimination can be realized while input impedance matching is realized.

Description

Technical Field

[0001] The utility model relates to the field of semiconductor integrated circuits, and particularly relates to a millimeter-wave broadband low-noise amplifier based on dual-path noise cancellation. Background Technique

[0002] The low-noise amplifier is the first active module in the receiver link, mainly used to amplify the signal and suppress the noise of the subsequent circuit. Its performance has a very crucial impact on the receiver system. If the gain of the LNA is too low, it will not be able to suppress the influence of the subsequent circuit module on the overall system noise performance, which will interfere with the transmission of useful signals. If the noise figure of the LNA is too large, it will directly deteriorate the system noise characteristics, which will deteriorate the sensitivity of the receiver system. Moreover, due to the aggravation of parasitic effects such as metal interconnects and transistors in the millimeter-wave band, it is challenging to design a millimeter-wave broadband low-noise amplifier with high gain and low noise figure.

[0003] Generally speaking, the noise cancellation technology identifies two nodes in the main amplifier where the signal and noise have opposite polarities, and then their voltages are scaled by the auxiliary amplifier and synthesized with the voltage of the main amplifier at the output. The most basic dual-path noise cancellation topology is as Figure 1 shown in [1], the main path is a common-gate transistor, and the auxiliary path is a common-source transistor. When the condition of g m1 R1 = g m2 R2 is satisfied, the signal is enhanced at the output port while the channel current noise of the common-gate transistor is canceled at the same port. However, in the design of the millimeter-wave band, parasitic effects will be more significant, and phase and amplitude mismatches will inevitably occur in the main path and the auxiliary path, reducing the performance of noise cancellation.

[0004] Figure 2 A technique is introduced that uses the second-stage amplifier and phase adjustment circuit [2], where P1 and P2 adjust the gain and phase respectively to correct the amplitude-phase imbalance of the signals in the main path and the auxiliary path. However, implementing the phase adjustment circuit will cause additional area loss, and if passive devices are included, it will cause significant losses in the millimeter-wave band. Moreover, the output of the first-stage amplifier requires two transformers to achieve inter-stage matching of the common-gate and common-drain transistors respectively, resulting in an increase in chip area. To isolate the DC operating points of the common-gate and common-source transistors, a blocking capacitor C1 is required, but it will cause an additional change in the signal phase, resulting in a greater dual-path phase mismatch. Figure 3Another deep noise cancellation scheme [3] is introduced. In order to eliminate noise more thoroughly, the second stage needs to use four pairs of transformers to form the output of the fully differential noise cancellation stage. The large number of transformers not only increases the complexity of design and layout, but also results in the disadvantage of increased chip area. In addition, this structure also faces the problem of additional signal phase change caused by the DC blocking capacitor C1.

[0005] Among them, the references are as follows:

[0006] [1] Zhe Liu, Student Member, Chirn Chye Boon Chenyang Li, Kaituo Yang, Xiaopeng Yu and Yuan Liang, “A 0.061-mm2 1–11-GHz Noise-Canceling Low-Noise Amplifier Employing Active Feedforward With Simultaneous Current and Noise Reduction, IEEE Transactions on Microwave Theory and Techniques”, Vol. 69, No. 6, June 2021.

[0007] [2] Chinese Patent “A Noise Cancellation Circuit for a Low-Noise Amplifier”, Application No. 202110120958.4.

[0008] [3] Chinese Patent “A Low-Noise Amplifier with Deep Noise Cancellation”, Application No. 202310183313.4. Summary of the Utility Model

[0009] The purpose of the present utility model is to provide a millimeter-wave broadband low-noise amplifier based on dual-channel noise cancellation to solve the problems existing in the above-mentioned prior art.

[0010] The millimeter-wave broadband low-noise amplifier based on dual-channel noise cancellation in the present utility model includes a first-stage amplifier, an asymmetric output transformer, a second-stage amplifier, and an output balun structure connected in sequence; among them,

[0011] The first-stage amplifier includes a third transistor, a fourth transistor, and a coupling network composed of a first inductor, a second inductor, and a third inductor; the same-named terminal of the first inductor is connected to one end of the DC-blocking capacitor, the other end of the first inductor is simultaneously connected to the source of the third transistor and the same-named terminal of the second inductor, the drain of the third transistor serves as an output terminal of the first-stage amplifier, the same-named terminal of the third inductor is connected to the gate of the fourth transistor, the other end of the third inductor is connected to the gate of the third transistor, the third inductor is provided with a center tap, and the bias voltages input to the two transistors at the center tap are both VG; the source of the fourth transistor is grounded, and the drain of the fourth transistor serves as the other output terminal of the first-stage amplifier.

[0012] For further improvement, the drains of the third transistor and the fourth transistor are both connected to the input terminal of the asymmetric output transformer through a tuning circuit composed of a tuning capacitor and a tuning inductor.

[0013] For further improvement, the asymmetric output transformer includes a first primary inductor, a second primary inductor, a first secondary inductor, and a second secondary inductor; the inductance values of the first primary inductor and the second primary inductor are not equal, the same-named terminals of the first primary inductor and the second primary inductor respectively serve as the two input terminals of the asymmetric output transformer, the other end of the first primary inductor is connected to the other end of the second primary inductor as the power input terminal of the asymmetric output transformer; the same-named terminals of the first secondary inductor and the second secondary inductor serve as the two output terminals of the asymmetric output transformer, and the other ends of the first secondary inductor and the second secondary inductor are connected to each other.

[0014] Furthermore, the inductance values of the first secondary inductor and the second secondary inductor are the same.

[0015] For further improvement, the second-stage amplifier includes a fifth capacitor, a sixth capacitor, a first transistor, and a second transistor; one ends of the fifth capacitor and the sixth capacitor are respectively connected to the two output terminals of the asymmetric output transformer, the other end of the fifth capacitor is connected to the drain of the first transistor as an output terminal of the second-stage amplifier, the other end of the sixth capacitor is connected to the drain of the second transistor as the other output terminal of the second-stage amplifier, and the sources of the first transistor and the second transistor are both grounded.

[0016] Furthermore, a seventh capacitor serving as an output matching capacitor is connected between the two output terminals of the second-stage amplifier.

[0017] For further improvement, a second capacitor is connected to the connection end of the DC-blocking capacitor and the first inductor.

[0018] The advantages of the millimeter-wave broadband low-noise amplifier based on dual-path noise cancellation in the present utility model are as follows:

[0019] 1. Compared with the traditional dual-path noise cancellation topology structure, a coupling network based on a triple-coupled transformer is loaded at the gate of the common-source transistor and the source of the common-gate transistor in the first-stage amplifier of this low-noise amplifier. It not only overcomes the disadvantage of additional phase mismatch caused by using isolation capacitors, but also can simultaneously achieve transconductance enhancement and noise cancellation while realizing input impedance matching.

[0020] 2. The output transformer adopts a structure with an asymmetric primary side and a symmetric secondary side, realizing the compensation of the signal amplitude and phase of the main path and the auxiliary path, reducing the phase and amplitude imbalance of the dual path, and having excellent noise cancellation performance; and a single transformer realizes the functions of two transformers for inter-stage matching, saving chip area.

[0021] 3. In order to further improve the gain and 3dB bandwidth, while controlling the deterioration degree of the noise figure and improving the stability of the overall circuit, the second-stage amplifier adopts a differential neutralization capacitor common-source structure, canceling the gate-drain feedback capacitor C of the common-source gd , increasing the stability and isolation degree of the overall circuit, and improving the gain. Description of the Drawings

[0022] Figure 1 is the circuit schematic diagram of the basic dual-path noise topology structure;

[0023] Figure 2 is the noise cancellation scheme of reference [2];

[0024] Figure 3 is the noise cancellation scheme of reference [3];

[0025] Figure 4 is the circuit schematic diagram of the low-noise amplifier of the present utility model;

[0026] Figure 5 is the waveform diagram of the gain simulation result of the low-noise amplifier of the present utility model;

[0027] Figure 6 is the waveform diagram of the NF and NF min simulation results of the low-noise amplifier of the present utility model. Detailed Embodiment

[0028] As Figure 4 shown, the millimeter-wave broadband low-noise amplifier based on dual-path noise cancellation described in the present utility model includes a first-stage amplifier, an asymmetric output transformer, a second-stage amplifier, and an output balun structure connected in sequence. The first-stage amplifier includes a third transistor M CG , a fourth transistor MCS and a coupling network based on a three-coupled transformer formed by a first inductor L IN , a second inductor L IP and a third inductor L IS . Among them, the third transistor M CG serves as the common-source transistor in this amplifier, and the fourth transistor M CS serves as the common-gate transistor in this amplifier. The same-name terminal of the first inductor L IN is connected to one end of the DC-blocking capacitor C1, and the other end of the first inductor L IN is connected to the source of the third transistor M CG . The same-name terminal of the second inductor L IP is simultaneously connected to one end of the first inductor L IN and the source of the third transistor M CG . The other end of the second inductor L IP is grounded. A second capacitor C2 is connected to the connection terminal of the DC-blocking capacitor C1 and the first inductor L IN for input matching. The drain of the third transistor M CG serves as an output terminal of the first-stage amplifier. The same-name terminal of the third inductor L IS is connected to the gate of the fourth transistor M CS . The other end of the third inductor L IS is connected to the gate of the third transistor M CG . The third inductor L IS is provided with a center tap, and the center tap inputs the bias voltage VG of the two transistors. The source of the fourth transistor M CS is grounded, and the drain of the fourth transistor M CS serves as another output terminal of the first-stage amplifier. The second inductor L IP and the third inductor L IS are respectively located at the source of the common-gate transistor and the gate of the common-source transistor, and form an input coupling network of the common-source transistor with the three-coupled transformer formed by the first inductor L IN . And because the bias voltage VG of the common-source and common-gate transistors is input at the center tap of the third inductor L IS , the RF signal directly flows into the common-source transistor through magnetic coupling without passing through the DC-blocking capacitor, reducing the phase mismatch between the two signals. In addition, the inductor of the common-gate not only provides the function of coupling signals, but also has the functions of realizing broadband input impedance matching and improving transconductance, achieving noise cancellation and gain improvement without introducing additional phase errors.

[0029] In the first-stage amplifier, the drain of the third transistor M CG and the fourth transistor M CSThe drains are all connected to the input end of the asymmetric output transformer through a tuning network composed of tuning and tuning inductance, improving the inter-stage matching between the first-stage amplifier and the second-stage amplifier.

[0030] The asymmetric output transformer includes a first primary inductance L p1 , a second primary inductance L p2 , a first secondary inductance L s1 and a second secondary inductance L << s2 >>. The inductance values of the first primary inductance L p1 and the second primary inductance L p2 are not equal, while the inductance values of the first secondary inductance L s1 and the second secondary inductance L s2 are consistent. The same-name ends of the first primary inductance L p1 and the second primary inductance L p2 are respectively used as the two input ends of the asymmetric output transformer. The other end of the first primary inductance L p1 is connected to the other end of the second primary inductance L p2 , serving as the power input end of the asymmetric output transformer. The same-name ends of the first secondary inductance L s1 and the second secondary inductance L s2 are used as the two output ends of the asymmetric output transformer. The other end of the first secondary inductance L s1 is connected to the other end of the second secondary inductance L s2 . The output of the first-stage amplifier passes through a transformer with an asymmetric primary side and a symmetric secondary side structure, that is, the first primary inductance L p1 and the second primary inductance L p2 have unequal values, forming the primary side of the first-stage output asymmetric transformer, and compensating for the signal amplitude and phase of the main path and the auxiliary path through the asymmetric output transformer.

[0031] The second-stage amplifier includes a fifth capacitor C neu1 , a sixth capacitor C neu2 , a first transistor M1, and a second transistor M2. One ends of the fifth capacitor C neu1 and the sixth capacitor C neu2 are respectively connected to the two output ends of the asymmetric output transformer. The other end of the fifth capacitor C neu1 is connected to the drain of the first transistor M1 as one output end of the second-stage amplifier. The other end of the sixth capacitor C neu2 is connected to the drain of the second transistor M2 as the other output end of the second-stage amplifier. The sources of the first transistor M1 and the second transistor M2 are both grounded. Among them, the fifth capacitor C neu1 and the sixth capacitor C neu2 serve as neutralizing capacitors.

[0032] For the common-source structure, the gate-drain capacitance may cause problems of reduced stability and gain. To improve the differential stability and gain of the circuit, the second-stage amplifier of the low-noise amplifier adopts a differential common-source circuit and neutralization capacitance technology. Since one of the purposes of the neutralization capacitance is to reduce the reverse isolation of the second stage, the minimum isolation is taken as the optimization goal during the circuit design process, while taking into account other circuit parameter indicators. To improve the stability and reverse isolation of the second-stage circuit, and considering other indicators of the circuit at the same time, the neutralization capacitance value that makes the noise figure NF moderate and the isolation minimum is selected.

[0033] In addition, a seventh capacitor C7 is connected in parallel between the two output terminals of the second-stage amplifier of this embodiment to adjust the output matching of the low-noise amplifier.

[0034] The output balun structure is as Figure 4 shown, which is a transformer with two primary inductors and two secondary inductors. Since the present utility model does not improve it and it is prior art, no more discussion will be made on it.

[0035] As Figures 5-6 shown, the overall design of the low-noise amplifier of the present utility model adopts a noise cancellation architecture, which preferably cancels the channel current noise of the common-gate transistor, and finally achieves a 3dB gain bandwidth of 20.9 - 45.4GHz, and the lowest noise figure in the band is 3.23dB; the loading of the transformer-based coupling network of the first-stage amplifier achieves excellent noise matching while realizing impedance matching, making NF and NF min very close within the bandwidth.

[0036] For those skilled in the art, various corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all these changes and deformations should fall within the protection scope of the claims of the present utility model.

Claims

1. A millimeter-wave broadband low-noise amplifier based on dual-channel noise cancellation, characterized in that It includes a first-stage amplifier, an asymmetric output transformer, a second-stage amplifier, and an output balun structure connected in sequence; wherein, The first-stage amplifier includes a third transistor (M CG ), a fourth transistor (M CS ), and a coupling network formed by a first inductor (L IN ), a second inductor (L IP ), and a third inductor (L IS ); the same-name end of the first inductor (L IN ) is connected to one end of the DC-blocking capacitor (C1), and the other end of the first inductor (L IN ) is simultaneously connected to the source of the third transistor (M CG ) and the same-name end of the second inductor (L IP ). The drain of the third transistor (M CG ) serves as an output terminal of the first-stage amplifier. The same-name end of the third inductor (L IS ) is connected to the gate of the fourth transistor (M CS ), and the other end of the third inductor (L IS ) is connected to the gate of the third transistor (M CG ). The third inductor (L IS ) has a center tap, and the center tap inputs the bias voltage VG of the transistor. The source of the fourth transistor (M CS ) is grounded, and the drain of the fourth transistor (M CS ) serves as another output terminal of the first-stage amplifier.

2. The millimeter-wave broadband low-noise amplifier based on dual-channel noise cancellation according to claim 1, wherein The drain of the third transistor (M CG ) and the drain of the fourth transistor (M CS ) are both connected to the input end of the asymmetric output transformer through a tuning circuit composed of a tuning capacitor and a tuning inductor.

3. The millimeter-wave broadband low-noise amplifier based on dual-channel noise cancellation according to claim 1, characterized in that, The described asymmetric output transformer includes a first primary inductor (L p1 ), a second primary inductor (L p2 ), a first secondary inductor (L s1 ) and a second secondary inductor (L s2 ); the inductance values of the first primary inductor (L p1 ) and the second primary inductor (L p2 ) are not equal. The same-name terminals of the first primary inductor (L p1 ) and the second primary inductor (L p2 ) are respectively used as the two input terminals of the asymmetric output transformer. The other end of the first primary inductor (L p1 ) is connected to the other end of the second primary inductor (L p2 ) to serve as the power input terminal of the asymmetric output transformer; the same-name terminals of the first secondary inductor (L s1 ) and the second secondary inductor (L s2 ) are used as the two output terminals of the asymmetric output transformer. The other end of the first secondary inductor (L s1 ) is connected to the other end of the second secondary inductor (L s2 ).

4. The millimeter-wave broadband low-noise amplifier based on dual-channel noise cancellation according to claim 3, wherein The inductance values of the first secondary inductor (L s1 ) and the second secondary inductor (L s2 ) are the same.

5. The millimeter-wave broadband low-noise amplifier based on dual-channel noise cancellation according to claim 1, wherein The second-stage amplifier includes a fifth capacitor (C neu1 ), a sixth capacitor (C neu2 ), a first transistor (M1), and a second transistor (M2); one ends of the fifth capacitor (C neu1 ) and the sixth capacitor (C neu2 ) are respectively connected to two output terminals of the asymmetric output transformer, the other end of the fifth capacitor (C neu1 ) is connected to the drain of the first transistor (M1) as an output terminal of the second-stage amplifier, the other end of the sixth capacitor (C neu2 ) is connected to the drain of the second transistor (M2) as another output terminal of the second-stage amplifier, and the sources of the first transistor (M1) and the second transistor (M2) are both grounded.

6. The millimeter-wave broadband low-noise amplifier based on dual-channel noise cancellation according to claim 5, wherein A seventh capacitor (C7) serving as an output matching capacitor is connected between two output terminals of the second-stage amplifier.

7. The millimeter-wave broadband low-noise amplifier based on dual-channel noise cancellation according to claim 1, characterized in that, The connection terminal of the DC-blocking capacitor (C1) and the first inductor (L IN ) is connected with a second capacitor (C2).

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