Ultra-wideband low noise amplifier based on coupled line expansion technique
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-10
- Publication Date
- 2026-08-11
AI Technical Summary
[0008]本实用新型的目的在于提供一种基于耦合拓展技术的超宽带低噪声放大器，解决现有的超宽带低噪声放大器在带宽、噪声、阻抗匹配、面积及功耗等性能指标间存在难以协调的矛盾，导致其整体性能受限且难以满足高度集成化的应用需求的问题
[0016]本实用新型的一种基于耦合拓展技术的超宽带低噪声放大器，包括Cascode放大电路、输入耦合电感对和输出耦合电感对，通过采用由三端口耦合电感对构成的所述输入耦合电感对和所述输出耦合电感对相配合，利用其互感效应产生的负电动势为电路中的所述漏极寄生电容Cd和所述负载电容CL快速充电，显著减小充电时间，从而在无需牺牲噪声性能的前提下极大扩展了放大器的工作带宽，同时，该耦合结构固有的宽带特性简化了多级阻抗匹配网络的需求，在实现超宽带输入输出匹配(S11<-10dB)的同时，利用所述噪声优化电容Cex优化了噪声匹配，并通过复用电感功能有效减少了芯片面积和外围元件数量，最终在高集成度条件下协同解决了带宽、噪声、匹配与面积功耗间的矛盾。
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Abstract
Description
Technical Field
[0001] This utility model relates to the field of communication technology, and in particular to an ultra-wideband low-noise amplifier based on coupling extension technology. Background Technology
[0002] Ultra-wideband low-noise amplifiers are core front-end modules for wireless communication, radar detection, and satellite internet communication systems. They need to meet stringent requirements such as wide bandwidth coverage (typically 3.1–22 GHz), low noise figure (NF<3dB), high gain flatness, and good impedance matching.
[0003] Current mainstream technical solutions include:
[0004] 1. Distributed amplifier: It expands the bandwidth by stacking multiple gain units, but requires a large number of inductors, resulting in a large chip area and high power consumption;
[0005] 2. Resistive negative feedback structure: It is simple to implement and has a wide bandwidth, but it introduces additional thermal noise and worsens the noise figure.
[0006] 3. Parallel peaking technology: It uses LC resonance to extend the high-frequency bandwidth, but the gain flatness is sensitive to process fluctuations and the design tolerance is small.
[0007] In summary, existing ultra-wideband low-noise amplifiers suffer from unresolved contradictions in performance indicators such as bandwidth, noise, impedance matching, area, and power consumption, resulting in limited overall performance and difficulty in meeting the requirements of highly integrated applications. Utility Model Content
[0008] The purpose of this invention is to provide an ultra-wideband low-noise amplifier based on coupling extension technology, which solves the problem that existing ultra-wideband low-noise amplifiers have uncoordinated performance indicators such as bandwidth, noise, impedance matching, area and power consumption, resulting in limited overall performance and difficulty in meeting the needs of highly integrated applications.
[0009] To achieve the above objectives, this utility model provides an ultra-wideband low-noise amplifier based on coupling extension technology. The ultra-wideband low-noise amplifier based on coupling extension technology includes a Cascode amplifier circuit, an input coupling inductor pair, and an output coupling inductor pair. The Cascode amplifier circuit is composed of cascaded transistors M1 and M2. The input terminal of the input coupling inductor pair serves as the input terminal of the radio frequency signal, the output terminal of the input coupling inductor pair is connected to the gate of transistor M1, the input terminal of the output coupling inductor pair is connected to the drain of transistor M2, and the output terminal of the output coupling inductor pair serves as the output terminal of the radio frequency signal.
[0010] The input terminal of the input coupling inductor pair is connected to the input matching capacitor C1 and then grounded. The output terminal of the input coupling inductor pair is provided with a noise optimization capacitor Cex. The end of the noise optimization capacitor Cex away from the input coupling inductor pair is connected to the source of the transistor M1 and grounded. The drain node of the transistor M2 has a drain parasitic capacitance Cd. The output terminal of the output coupling inductor pair is provided with a load capacitor CL.
[0011] Both the input coupling inductor pair and the output coupling inductor pair are three-port coupling inductor pair structures with a center tap. The input coupling inductor pair is composed of a first inductor L1 and a second inductor L2 coupled together, and the output coupling inductor pair is composed of a third inductor L3 and a fourth inductor L4 coupled together.
[0012] A DC blocking capacitor CB is provided at both the input and output terminals of the radio frequency signal.
[0013] The transistor M2 has a bias resistor R1 at its gate, and the end of the bias resistor R1 away from the transistor is connected to the bias voltage terminal Vcas.
[0014] The end of the first inductor furthest from the second inductor is connected to the voltage terminal V6.
[0015] Among them, the first inductor L1, the second inductor L2, the third inductor L3 and the fourth inductor L4 are all on-chip planar spiral inductors.
[0016] This invention discloses an ultra-wideband low-noise amplifier based on coupling extension technology, comprising a Cascode amplifier circuit, an input coupling inductor pair, and an output coupling inductor pair. By employing the input and output coupling inductor pairs, which are composed of three-port coupling inductors, the negative electromotive force generated by their mutual inductance effect rapidly charges the drain parasitic capacitance Cd and the load capacitance CL in the circuit, significantly reducing the charging time. This greatly expands the amplifier's operating bandwidth without sacrificing noise performance. Simultaneously, the inherent wideband characteristics of this coupling structure simplify the requirements of multi-stage impedance matching networks. While achieving ultra-wideband input-output matching (S11 < -10dB), the noise optimization capacitor Cex optimizes noise matching, and the reuse of inductor functions effectively reduces chip area and the number of external components. Ultimately, under high integration conditions, the contradiction between bandwidth, noise, matching, area, and power consumption is resolved collaboratively. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of the three-port coupled inductor pair structure provided by this utility model.
[0019] Figure 2 This is a schematic diagram of the equivalent model of the three-port coupled inductor pair structure after decoupling provided by this utility model.
[0020] Figure 3 This is a schematic diagram of the circuit structure of the ultra-wideband low-noise amplifier based on coupling extension technology provided by this utility model.
[0021] Figure 4 This is the equivalent circuit diagram of the output terminal of the ultra-wideband low-noise amplifier based on coupling extension technology provided by this utility model after decoupling.
[0022] Figure 5 This is a schematic diagram of the S-parameter curves of the ultra-wideband low-noise amplifier based on coupling extension technology provided by this utility model.
[0023] Figure 6 This is a schematic diagram of the noise figure curve of the ultra-wideband low-noise amplifier based on coupling extension technology provided by this utility model. Detailed Implementation
[0024] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.
[0025] Please see Figures 1 to 6 This invention provides an ultra-wideband low-noise amplifier based on coupling extension technology. The ultra-wideband low-noise amplifier based on coupling extension technology includes a Cascode amplifier circuit, an input coupling inductor pair, and an output coupling inductor pair. The Cascode amplifier circuit is composed of cascaded transistors M1 and M2. The input terminal of the input coupling inductor pair serves as the input terminal of the radio frequency signal. The output terminal of the input coupling inductor pair is connected to the gate of transistor M1. The input terminal of the output coupling inductor pair is connected to the drain of transistor M2. The output terminal of the output coupling inductor pair serves as the output terminal of the radio frequency signal.
[0026] The input terminal of the input coupling inductor pair is connected to the input matching capacitor C1 and then grounded. The output terminal of the input coupling inductor pair is provided with a noise optimization capacitor Cex. The end of the noise optimization capacitor Cex away from the input coupling inductor pair is connected to the source of the transistor M1 and grounded. The drain node of the transistor M2 has a drain parasitic capacitance Cd. The output terminal of the output coupling inductor pair is provided with a load capacitor CL.
[0027] Both the input coupling inductor pair and the output coupling inductor pair are three-port coupling inductor pair structures with a center tap. The input coupling inductor pair is composed of a first inductor L1 and a second inductor L2 coupled together, and the output coupling inductor pair is composed of a third inductor L3 and a fourth inductor L4 coupled together.
[0028] In this embodiment, by employing the input coupling inductor pair and the output coupling inductor pair, which are composed of three-port coupled inductor pairs, the negative electromotive force generated by their mutual inductance effect is used to quickly charge the drain parasitic capacitance Cd and the load capacitance CL in the circuit, significantly reducing the charging time. This greatly expands the operating bandwidth of the amplifier without sacrificing noise performance. At the same time, the inherent broadband characteristics of this coupling structure simplify the requirements of multi-stage impedance matching networks. While achieving ultra-wideband input-output matching (S11 < -10dB), the noise matching is optimized by using the noise optimization capacitor Cex. Furthermore, the chip area and the number of external components are effectively reduced by reusing the inductor function. Ultimately, the contradiction between bandwidth, noise, matching, area, and power consumption is resolved collaboratively under high integration conditions.
[0029] In this technical solution, both the input coupled inductor pair and the output coupled inductor pair are three-port coupled inductor pair structures with center taps. By utilizing the unique characteristics of coupled inductors and performing decoupling equivalent processing on the coupled inductors, the circuit containing mutual inductance is transformed into an equivalent circuit containing only self-inductance (no mutual inductance), allowing Kirchhoff's laws and conventional circuit analysis methods to be directly applied.
[0030] Specifically, such as Figure 1 As shown, the actual structural diagram of the three-port coupled inductor pair structure used in this technical solution is as follows: the two inductors are wound in the same direction and have a center tap (C terminal), forming a three-port device (A terminal, B terminal, C terminal). Due to the existence of mutual inductance M, directly analyzing the impact of this device on the circuit is quite complex.
[0031] To simplify the analysis, the coupled inductors need to be decoupled and equivalently processed. The core of this is based on the law of electromagnetic induction, which transforms a circuit containing mutual inductance into an equivalent circuit containing only self-inductance (no mutual inductance), thus allowing the direct application of conventional circuit analysis methods such as Kirchhoff's laws.
[0032] See Figure 2 , it is Figure 1 The diagram shows the decoupling equivalent circuit of the three-port coupled inductor model. The derivation of this equivalent model is as follows:
[0033] right Figure 1 The three-port network shown is subjected to decoupling equivalent analysis, and KVL analysis is performed on both the ac and bc ends respectively:
[0034]
[0035] i C (t)=i A (t)+i B (t) (3)
[0036] Substituting formula (3) into formula (1) and formula (2) respectively, we get:
[0037]
[0038] The equivalent decoupled circuit structure derived from formulas (3) and (4) is as follows: Figure 2 As shown.
[0039] As can be seen from the decoupling equivalent circuit, a negative electromotive force will be generated at the C terminal of the main branch due to the presence of the -M inductance:
[0040]
[0041] This technical solution utilizes the negative electromotive force generated by the coupled inductor to rapidly charge the load capacitor and the drain parasitic capacitance, thereby reducing the capacitor response time and achieving the goal of expanding the bandwidth.
[0042] Furthermore, the working principle of this technical solution, especially its ability to expand bandwidth, can be clearly demonstrated by analyzing the output network.
[0043] See Figure 4 This is the decoupling equivalent circuit diagram of the output network section (i.e., L3, L4, Cd, CL) of this utility model. This diagram is based on the decoupling equivalent processing of the coupled inductors. Figure 3 The output coupling inductance pair (L3 / L4) is obtained by equivalent transformation.
[0044] In this equivalent circuit:
[0045] The third inductor L3 is equivalent to an inductor with an inductance value of (L3+M) connected in series with a negative inductor with a value of -M.
[0046] The fourth inductor L4 is equivalent to an inductance value of (L4+M).
[0047] The Cascode amplifier circuit is equivalent to a controlled current source (gm·Vgs).
[0048] The working principle of its bandwidth expansion is explained from the time domain perspective as follows:
[0049] After power-on, the initial current begins to charge the capacitors in the circuit. In the equivalent circuit... Figure 4 In this circuit, the current flowing through the (L4+M) branch accelerates the charging of the drain parasitic capacitance Cd. Simultaneously, and crucially, the current flowing through the -M negative inductor branch generates a negative electromotive force Vm (left negative, right positive). This Vm electromotive force effectively promotes the charging speed of the load capacitance CL.
[0050] Therefore, the charging processes of the drain parasitic capacitance Cd and the load capacitance CL can be completed simultaneously and rapidly, greatly shortening the total charging time. In the frequency domain, this effect manifests as a significant expansion of the circuit's -3dB bandwidth.
[0051] In contrast, in traditional circuits lacking the negative electromotive force effect of coupled inductors, the initial current cannot quickly charge CL during power-up; the charging process of Cd must be completed first before charging CL can begin. This series-type charging process is time-consuming, severely limiting the bandwidth of radio frequency signals.
[0052] Furthermore, a DC blocking capacitor CB is provided at both the input and output terminals of the radio frequency signal.
[0053] In this embodiment, the DC blocking capacitor CB is used to isolate DC signals.
[0054] Furthermore, a bias resistor R1 is provided at the gate of the transistor M2, and the end of the bias resistor R1 away from the transistor is connected to the bias voltage terminal Vcas, and the end of the first inductor away from the second inductor is connected to the voltage terminal V6.
[0055] Furthermore, the first inductor L1, the second inductor L2, the third inductor L3, and the fourth inductor L4 are all on-chip planar spiral inductors.
[0056] In summary, please refer to Figure 5 The paper presents the S-parameter simulation results of an ultra-wideband low-noise amplifier based on coupling extension technology. It shows that the amplifier's -3dB bandwidth covers an ultra-wide range from 4.5GHz to 24GHz, and it exhibits excellent gain flatness.
[0057] See Figure 6The results show the noise figure (NF) simulation of an ultra-wideband low-noise amplifier based on coupling extension technology. The noise figure is below 2dB across an extremely wide bandwidth from 2GHz to 27GHz, successfully overcoming the traditional trade-off between bandwidth and noise in broadband amplifiers, while simultaneously achieving ultra-wideband, low noise, and high gain flatness.
[0058] Therefore, this technical solution effectively solves the core contradiction in the design of ultra-wideband low-noise amplifiers by introducing an innovative coupled inductor structure and utilizing its generated negative electromotive force effect, and has extremely high practical value and industrial prospects.
[0059] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Those skilled in the art can understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present utility model are still within the scope of the utility model.
Claims
1. An ultrawideband low-noise amplifier based on coupling extension technology, characterized in that, It includes a Cascode amplifier circuit, an input coupling inductor pair, and an output coupling inductor pair. The Cascode amplifier circuit is composed of cascaded transistors M1 and M2. The input terminal of the input coupling inductor pair serves as the input terminal of the radio frequency signal. The output terminal of the input coupling inductor pair is connected to the gate of transistor M1. The input terminal of the output coupling inductor pair is connected to the drain of transistor M2. The output terminal of the output coupling inductor pair serves as the output terminal of the radio frequency signal. The input terminal of the input coupling inductor pair is connected to the input matching capacitor C1 and then grounded. The output terminal of the input coupling inductor pair is provided with a noise optimization capacitor Cex. The end of the noise optimization capacitor Cex away from the input coupling inductor pair is connected to the source of the transistor M1 and grounded. The drain node of the transistor M2 has a drain parasitic capacitance Cd. The output terminal of the output coupling inductor pair is provided with a load capacitor CL. Both the input coupling inductor pair and the output coupling inductor pair are three-port coupling inductor pair structures with a center tap. The input coupling inductor pair is composed of a first inductor L1 and a second inductor L2 coupled together, and the output coupling inductor pair is composed of a third inductor L3 and a fourth inductor L4 coupled together.
2. The ultra-wideband low-noise amplifier based on coupling extension technology as described in claim 1, characterized in that, A DC blocking capacitor CB is provided at both the input and output terminals of the radio frequency signal.
3. The ultra-wideband low-noise amplifier based on coupling extension technology as described in claim 2, characterized in that, A bias resistor R1 is provided at the gate of the transistor M2, and the end of the bias resistor R1 away from the transistor is connected to the bias voltage terminal Vcas.
4. The ultra-wideband low-noise amplifier based on coupling extension technology as described in claim 3, characterized in that, The end of the first inductor furthest from the second inductor is connected to the voltage terminal V6.
5. The ultra-wideband low-noise amplifier based on coupling extension technology as described in claim 4, characterized in that, The first inductor L1, the second inductor L2, the third inductor L3 and the fourth inductor L4 are all on-chip planar spiral inductors.