Ultra-wideband low-noise distributed amplifier based on three-turn coupled inductors and multiple magnetic coupling feedback loops

Abstract

The present invention belongs to the field of integrated circuit technology, specifically an ultra-wideband, low-noise distributed amplifier based on three-turn coupled inductors and multiple magnetically coupled feedback loops. The circuit structure of the present invention includes a three-stage distributed amplifier; the first and third-stage distributed amplifiers are composed of a four-stage gain unit, a three-turn coupled inductor, and a two-turn coupled inductor; the gain unit is a common-source common-gate structure, with the gate, source, and drain series inductors of the common-gate transistor forming a multiple magnetically coupled feedback loop; this structure increases the equivalent transconductance of the common-gate transistor, effectively reducing the noise contribution of the transistor; the three-turn coupled inductor serves as a unit circuit for the gate transmission line, including a gate transmission line unit inductor and a common-source transistor source series inductor; the two-turn coupled inductor serves as a unit circuit for the drain transmission line; the second-stage distributed amplifier is composed of a single-stage common-source common-gate gain unit; and the gate terminal circuit of the first-stage distributed amplifier effectively reduces the noise contribution of the resistor therein.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated circuits, and in particular relates to an ultra-wideband low-noise distributed amplifier. Background Art

[0002] Millimeter-wave spectrum detection equipment needs to detect signals across various frequency bands. This involves a wide spectrum range and numerous signal protocols, including 5G, Wi-Fi 6, radar, and other communication protocols, as well as other encryption protocols for public defense and security. Currently, spectrum detection equipment of different standards is required for different types of signals in different frequency bands. To improve the integration of spectrum detection equipment, the design of broadband millimeter-wave spectrum detection receiver chips is particularly important. As the front-end circuit of the receiver, the low-noise amplifier (LNA) determines the overall receiver's reception signal range, noise figure, linearity, and other performance characteristics. Therefore, the LNA circuit design is crucial for the entire receiver. From a circuit structure perspective, LNAs can be categorized as either lumped or distributed. Distributed circuits are the preferred LNA architecture because they can achieve bandwidths exceeding one octave.

[0003] The distributed amplifier circuit includes a gate artificial transmission line, a drain artificial transmission line, a terminal matching resistor, and a gain unit. The input signal is input from the input end of the gate artificial transmission line, and the other end of the gate artificial transmission line is connected to a matching resistor, which also serves as a bias voltage feed path. The output signal is output from the output end of the drain artificial transmission line, and the other end of the drain artificial transmission line is connected to a matching resistor, which also serves as a power supply voltage feed circuit. The gate artificial transmission line is composed of a lumped inductor element and the parasitic capacitance of the transistor gate, and the drain artificial transmission line is composed of a lumped inductor element and the parasitic capacitance of the transistor drain. The characteristic impedance of the artificial transmission line must be the same as the terminal matching resistor value. The gain unit is usually a common source and common gate structure. A peaking inductor is connected in series between the drain of the common source transistor and the source of the common gate transistor to reduce the leakage component of the RF signal through the parasitic capacitance and increase the circuit bandwidth.

[0004] The key difficulties in designing low-noise distributed amplifier circuits are noise optimization of common-source transistors and gate transmission line terminal matching resistors, as well as designing a circuit that maintains wide bandwidth and high gain while achieving low noise. Summary of the Invention

[0005] The object of the present invention is to provide an ultra-wideband low-noise distributed amplifier for a millimeter-wave spectrum detection broadband receiver, which achieves low noise while maintaining a large bandwidth and high gain.

[0006] The ultra-wideband low-noise amplifier proposed in the present invention for a millimeter-wave spectrum detection broadband receiver is based on a three-turn coupled inductor and a multi-magnetic coupling feedback loop. Its circuit structure includes a three-stage distributed amplifier. The first and third-stage distributed amplifiers are composed of a four-stage gain unit, wherein the three-turn coupled inductor serves as a unit circuit for the gate transmission line, and similarly, the two-turn coupled inductor serves as a unit circuit for the drain transmission line. The second-stage distributed amplifier is composed of a single-stage gain unit. The gate terminal of the first-stage distributed amplifier is implemented using a terminal circuit, replacing the traditional 50-ohm resistor.

[0007] In the present invention, the gain unit 1 is a common source and common gate structure, including a common source transistor M1 and a common gate transistor M2 and other passive structures. Among them, the source series inductor L4 of the common gate transistor M2 forms a magnetic coupling feedback loop with the gate series inductor L5 and the drain series inductor L6 respectively; at a higher operating frequency, the RF signal will leak to the ground through the intrinsic parasitic capacitance of the transistor, causing the high-frequency gain of the transistor to decrease. The coupling effect of the inductor L4 and the inductor L5 can compensate for the parasitic capacitance C gs This prevents signal leakage, thereby increasing the high-frequency gain of common-gate transistor M2 and improving the circuit bandwidth. The coupling effect of inductors L4 and L6 creates a positive feedback structure, coupling the drain output signal back to the source input for amplification by common-gate transistor M2. Both coupling effects increase the equivalent transconductance of common-gate transistor M2, thereby reducing its channel thermal noise.

[0008] In the present invention, the structure of the gain unit 2 is similar to that of the gain unit 1, except that the common-gate transistor of the gain unit 1 has series inductors at the gate, drain, and source, and presents a folded layout design; the common-gate transistor of the gain unit 2 has series inductors only at the drain and source, and does not have a folded layout design.

[0009] In the present invention, the three-turn coupled inductor includes inductor L1, inductor L2, and inductor L3. Inductor L1 and inductor L2 constitute a unit circuit of the gate transmission line, and inductor L3 is the source series inductor of transistor M1. There is a coupling effect between each of the three inductors. The coupling effect between inductor L3 and inductor L1, and between inductor L3 and inductor L2, can effectively increase the transconductance of transistor M1, thereby reducing the channel thermal noise of transistor M1. The coupling effect between inductor L1 and inductor L2 can reduce the amplitude of the change in the characteristic impedance of the gate transmission line with frequency, thereby optimizing the input matching performance of the circuit.

[0010] In the present invention, the circuit structure of the two-loop inductive coupling structure is similar to that of the three-loop inductive coupling structure, except that the two-loop inductive coupling structure only includes inductors L1 and L2, and does not include the source series inductor L3; wherein, inductors L1 and L2 constitute the unit circuit of the drain transmission line; the layout structure differs in that the two-loop inductive coupling structure removes the layout structure of inductor L3 compared to the three-loop inductive coupling structure, while the layout structures of inductors L1 and L2 remain unchanged and are still octagonal structures.

[0011] In the present invention, the terminal circuit includes a parallel resistor R g and transistor capacitance C g . Transistor capacitance represents C g The replacement of interdigital capacitors can make the trend of capacitance change with process temperature and voltage consistent with that of transistors, thereby reducing mismatch. The parallel RC terminal circuit replaces the traditional pure resistance terminal circuit, which causes impedance mismatch between the terminal circuit and the transmission line, resulting in an increase in the reflection coefficient at the input end of the terminal circuit. This phenomenon prevents the thermal noise generated by the resistors in the terminal circuit from reaching the input end through the transmission line, and part of it is reflected. Therefore, the terminal circuit effectively reduces the resistance R g Noise contribution to the circuit.

[0012] The distributed amplifier designed in the present invention adopts three-turn coupled inductor, multiple magnetic coupling feedback loops and terminal circuit technology to achieve noise optimization under wide bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the structure of the ultra-wideband low-noise distributed amplifier of the present invention.

[0014] Figure 2 The circuit diagram and partial layout of the three-turn coupled inductor structure and transistor M1.

[0015] Figure 3 The circuit diagram and partial layout of the multi-magnetic coupling feedback loop and transistor M2.

[0016] Figure 4 This is a schematic diagram of the terminal circuit structure.

[0017] In the figure, reference numerals 100 denotes a three-stage cascade architecture of an ultra-wideband low-noise distributed amplifier according to the present invention; 101 denotes a first-stage amplifier; 102 denotes a second-stage amplifier; and 103 denotes a third-stage amplifier. 104 denotes a first gain unit; 105 denotes a second gain unit; 106 denotes a two-turn inductive coupling structure; 107 denotes a terminal circuit; and 108 denotes a three-turn inductive coupling structure. DETAILED DESCRIPTION

[0018] The present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, identical elements are represented by similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale. In addition, some well-known parts may not be shown in the drawings.

[0019] The structure of the ultra-wideband low-noise distributed amplifier of the present invention is shown in FIG. Figure 1 As shown, the ultra-wideband low-noise distributed amplifier 100 adopts a three-stage cascade architecture, including a first-stage amplifier 101, a second-stage amplifier 102, and a third-stage amplifier 103. The first-stage amplifier 101 is composed of a distributed amplifier consisting of four stages of gain units 104, the second-stage amplifier 102 is composed of a single-stage cascade distributed amplifier consisting of a first-stage gain unit 105, and the third-stage amplifier 103 is composed of a distributed amplifier consisting of four stages of gain units 104. Gain unit 104 and gain unit 2 105 both adopt a common-source common-gate structure, including a common-source transistor M1 and a common-gate transistor M2; the three ports of the common-source transistor M1 are respectively a gate, a drain, and a source; wherein the gate is a signal input terminal, the drain is a signal output terminal, and the source is shorted to a ground signal; the three ports of the common-gate transistor M2 are respectively a gate, a drain, and a source; wherein the source is a signal input terminal, the drain is a signal output terminal, and the gate is shorted to a ground signal; the common-source common-gate structure short-circuits the drain of the common-source transistor and the source of the common-gate transistor, and the signal input terminal of the structure is the gate of the common-source transistor, and the signal output terminal is the drain of the common-gate transistor;

[0020] The source series inductor, gate series inductor and drain series inductor of the common-gate transistor form a multi-magnetic coupling feedback loop, which is included in the gain unit 104;

[0021] The difference between the gain unit 104 and the gain unit 2 105 is that the common-gate transistor of the gain unit 104 has series inductors at the gate, drain, and source, and exhibits a folded layout design; the common-gate transistor of the gain unit 2 105 has series inductors only at the drain and source, and does not exhibit a folded layout design.

[0022] The gate transmission line unit circuits of the first-stage amplifier 101 and the third-stage amplifier 103 adopt a three-loop inductive coupling structure 108;

[0023] To ensure the consistency of the gate and drain signal phases of the first-stage amplifier 101 and the second-stage amplifier 102, the drain transmission line adopts a two-loop inductive coupling structure 106 similar to the gate transmission line unit circuit;

[0024] The gate transmission line terminal of the first stage amplifier 101 is terminated by a terminal circuit 107 instead of the original matching resistor;

[0025] The power supply voltage VDD of the first stage amplifier 101 and the third stage amplifier 103 is connected to the resistor Z d The power supply voltage VDDC of the second stage amplifier 102 is fed through the resistor Z g Feeding power;

[0026] The resistance Z d and resistor Z g It also has port matching function.

[0027] In the present invention, the circuit diagram and partial layout of the three-circle inductive coupling structure 108 and the transistor M1 can be found in Figure 2 As shown, the three-loop coupled inductor structure 108 includes an inductor L1, an inductor L2, and an inductor L3; wherein, the inductor L1 and the inductor L2 constitute a unit circuit of the gate transmission line, and the inductor L3 is the source series inductor of the transistor M1; the coupling coefficient between the inductor L1 and the inductor L2 is k 12 , the coupling coefficient between inductor L1 and inductor L3 is k 13 , the coupling coefficient between inductor L2 and inductor L3 is k 23 The input RF signal passes through the gate transmission line and the coupling capacitor to the gate of transistor M1, and its bias voltage V G Power is supplied through a resistor of nearly 1,000 ohms. The coupling effect between inductor L3 and inductor L1, and between inductor L3 and inductor L2, can effectively increase the transconductance of transistor M1, thereby reducing the channel thermal noise of transistor M1. The coupling effect between inductor L1 and inductor L2 can reduce the amplitude of the gate transmission line characteristic impedance variation with frequency, thereby optimizing the input matching performance of the circuit. The layout design of inductor L1, inductor L2, and inductor L3 adopts an octagonal structure. The characteristic of this structure is that it can achieve a high quality factor, that is, it uses the smallest area while ensuring a certain inductance value. This layout design can effectively reduce the area proportion of the artificial transmission line inductor in the distributed amplifier and improve the area utilization of the circuit.

[0028] In the present invention, the circuit structure of the two-loop inductive coupling structure 106 is similar to that of the three-loop inductive coupling structure 108, except that the two-loop inductive coupling structure 106 only includes inductors L1 and L2, and does not include the source series inductor L3; wherein, inductors L1 and L2 constitute the unit circuit of the drain transmission line; the layout structure differs in that the two-loop inductive coupling structure 106 removes the layout structure of inductor L3 compared to the layout of the three-loop inductive coupling structure 108, while the layout structures of inductors L1 and L2 remain unchanged and are still octagonal structures.

[0029] In the present invention, the circuit diagram and partial layout of the multi-magnetic coupling feedback loop and transistor M2 are shown in FIG. Figure 3As shown. The multi-magnetic coupling feedback loop includes inductor L4, inductor L5 and inductor L6. Among them, inductor L4 is the source series inductor of transistor M2, inductor L5 is the gate series inductor of transistor M2, and inductor L6 is the drain series inductor of transistor M2, forming a multi-magnetic coupling feedback loop. The coupling coefficient between inductor L4 and inductor L5 is k 45 , the coupling coefficient between inductor L4 and inductor L6 is k 46 The input RF signal reaches the source of transistor M2 through inductor L4 and is output from the drain of transistor M2. The bias voltage V B Power is supplied through a resistor of nearly 1,000 ohms. At higher operating frequencies, RF signals will leak to the ground through the intrinsic parasitic capacitance of the transistor, causing a decrease in the high-frequency gain of the transistor. The coupling effect of inductor L4 and inductor L5 can compensate for the parasitic capacitance C gs Signal leakage is prevented, thereby increasing the high-frequency gain of transistor M2 and improving the circuit bandwidth. The coupling effect of inductors L4 and L6 forms a positive feedback structure, where the drain output signal is coupled back to the source input for amplification by transistor M2. Both coupling effects increase the equivalent transconductance of transistor M2, thereby reducing its channel thermal noise. Inductors L4, L5, and L6 utilize a folded layout design, achieving magnetic coupling while reducing the inductor area. This effectively reduces the area of ​​the gain unit in the distributed amplifier and improves the circuit's area utilization.

[0030] In the present invention, the terminal circuit 107 structure is as follows: Figure 4 The terminal circuit 107 includes a parallel resistor R g and transistor capacitance C g . The transistor capacitance C g One end is the transistor gate, and the other end is the parallel connection of the transistor source and drain. g Replacing the interdigital capacitor can make the trend of the capacitance changing with process temperature and voltage consistent with that of the transistor, thereby reducing mismatch. The parallel RC terminal circuit causes impedance mismatch between it and the gate transmission line, resulting in an increase in the reflection coefficient at the input end of the terminal circuit. This phenomenon prevents the thermal noise generated by the resistor in the terminal circuit from passing through the transmission line to the input end of the gate transmission line, and part of it is reflected. Therefore, the terminal circuit effectively reduces the resistance R g Noise contribution to the circuit.

[0031] In the present invention, a TSMC 28nm CMOS process is used for design. Post-layout simulation shows that the overall ultra-wideband low-noise distributed amplifier has a 3dB bandwidth of 3-119GHz, a maximum small-signal gain of 15.3dB within the 3dB bandwidth, and a minimum noise figure of 4.8dB within the 3dB bandwidth. The circuit is unconditionally stable within the 3dB bandwidth, with a minimum stability k factor of 103.9.

Claims

1. An ultra-wideband low-noise distributed amplifier based on three-turn coupled inductors and multiple magnetic coupling feedback loops, characterized in that: A three-stage cascade architecture is adopted, including a first-stage amplifier (101), a second-stage amplifier (102), and a third-stage amplifier (103); the first-stage amplifier (101) is composed of a distributed amplifier composed of four-stage gain units (104); the second-stage amplifier (102) is composed of a single-stage cascade distributed amplifier composed of a first-stage gain unit (105); and the third-stage amplifier (103) is composed of a distributed amplifier composed of four-stage gain units (104); both the gain unit (104) and the gain unit (105) adopt a common-source common-gate structure, and the common-source common-gate structure includes a common-source transistor M1 and a common-gate transistor M2; the three ports of the common-source transistor M1 are a gate, a drain, and a source, respectively; The gate is the signal input terminal, the drain is the signal output terminal, and the source is short-connected to the ground signal; the three ports of the common-gate transistor M2 are the gate, drain, and source respectively; The source is the signal input terminal, the drain is the signal output terminal, and the gate is shorted to the ground signal; the common source and common gate structure shorts the drain of the common source transistor M1 and the source of the common gate transistor M2. The signal input terminal of the structure is the gate of the common source transistor M1, and the signal output terminal is the drain of the common gate transistor M2. The source series inductor, gate series inductor and drain series inductor of the common-gate transistor form a multi-magnetic coupling feedback loop, which is included in the gain unit 1 (104); The difference between the gain unit 1 (104) and the gain unit 2 (105) is that the common-gate transistor of the gain unit 1 (104) has series inductance at the gate, drain and source, and presents a folded layout design; the common-gate transistor of the gain unit 2 (105) has series inductance only at the drain and source, and does not have a folded layout design; The drain transmission line unit circuits of the first-stage amplifier (101) and the third-stage amplifier (103) adopt a two-loop inductive coupling structure (106); The gate transmission line unit circuits of the first-stage amplifier (101) and the third-stage amplifier (103) adopt a three-loop inductive coupling structure (108); The original matching resistor at the gate transmission line terminal of the first-stage amplifier (101) is replaced by a terminal circuit (107); The power supply voltage VDD of the first stage amplifier (101) and the third stage amplifier (103) is connected through the resistor Z d For feeding, the power supply voltage VDDC of the second stage amplifier (102) is fed through the resistor Z g Feeding power; The resistance Z d and resistor Z g It also has port matching function.

2. The ultra-wideband low-noise distributed amplifier according to claim 1, wherein: The three-loop coupled inductor structure (108) includes a first inductor L1, a second inductor L2 and a third inductor L3; The first inductor L1 and the second inductor L2 constitute a unit circuit of the gate transmission line, and the third inductor L3 is the source series inductor of the transistor M1; the coupling coefficient between the first inductor L1 and the second inductor L2 is k 12 , the coupling coefficient between the first inductor L1 and the third inductor L3 is k 13 , the coupling coefficient between the second inductor L2 and the third inductor L3 is k 23 The input RF signal passes through the gate transmission line and the coupling capacitor to the gate of transistor M1, and its bias voltage V G Power is supplied through a resistor of nearly kilohms. The coupling effect between the third inductor L3 and the first inductor L1, and between the third inductor L3 and the second inductor L2, effectively increases the transconductance of the transistor M1, thereby reducing the channel thermal noise of the transistor M1. The coupling effect between the first inductor L1 and the second inductor L2 reduces the amplitude of the characteristic impedance of the gate transmission line varying with frequency, thereby optimizing the input matching performance of the circuit.

3. The ultra-wideband low-noise distributed amplifier according to claim 2, wherein: The layout design of the first inductor L1 , the second inductor L2 and the third inductor L3 adopts an octagonal structure.

4. The ultra-wideband low-noise distributed amplifier according to claim 2, wherein: The circuit structure of the two-loop inductive coupling structure (106) is similar to that of the three-loop inductive coupling structure (108), except that the two-loop inductive coupling structure (106) only includes the first inductor L1 and the second inductor L2; The first inductor L1 and the second inductor L2 constitute a unit circuit of the drain transmission line; and the layout structure is still an octagonal structure.

5. The ultra-wideband low-noise distributed amplifier according to claim 1, wherein: The magnetic coupling feedback loop includes a fourth inductor L4, a fifth inductor L5 and a sixth inductor L6; The fourth inductor L4 is the source series inductor of the transistor M2, the fifth inductor L5 is the gate series inductor of the transistor M2, and the sixth inductor L6 is the drain series inductor of the transistor M2, forming a multi-magnetic coupling feedback loop; the coupling coefficient between the fourth inductor L4 and the fifth inductor L5 is k 45 , the coupling coefficient between the fourth inductor L4 and the sixth inductor L6 is k 46 The input RF signal reaches the source of transistor M2 through the fourth inductor L4 and is output from the drain of transistor M2; the bias voltage V B Power is supplied through a resistor of nearly 1,000 ohms; the RF signal leaks to the ground through the intrinsic parasitic capacitance of the transistor M2 at a higher operating frequency, causing the high-frequency gain of the transistor M2 to decrease; the coupling effect of the fourth inductor L4 and the fifth inductor L5 can compensate for the parasitic capacitance C gs The signal leakage phenomenon is prevented, thereby increasing the high-frequency gain of the transistor M2 and improving the circuit bandwidth; the coupling effect of the fourth inductor L4 and the sixth inductor L6 forms a positive feedback structure, and the drain output signal returns to the source input terminal through coupling and is amplified by the transistor M2; both coupling effects increase the equivalent transconductance of the transistor M2, thereby reducing the channel thermal noise of the transistor M2.

6. The ultra-wideband low-noise distributed amplifier according to claim 4, characterized in that: The fourth inductor L4 , the fifth inductor L5 , and the sixth inductor L6 adopt a folded layout design.

7. The ultra-wideband low-noise distributed amplifier according to claim 1, wherein: The terminal circuit (107) includes a parallel resistor R g and transistor capacitance C g ; Transistor capacitance C g One end is the transistor gate, and the other end is the parallel connection of the transistor source and drain; Transistor capacitance C g Replacing the interdigital capacitor makes the trend of capacitance change with process temperature and voltage consistent with that of the transistor, thereby reducing mismatch; the parallel RC terminal circuit causes impedance mismatch between it and the gate transmission line, resulting in an increase in the reflection coefficient at the input end of the terminal circuit.

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