Parallel negative feedback ultra-wideband low noise amplifier based on cross-connection microstrip matching

Abstract

The application discloses a parallel negative feedback ultra-wideband low noise amplifier based on a cross knot type microstrip matching, wherein an input of the cross knot type input matching network is connected with a radio frequency signal, and an output is connected with a segmented negative feedback amplification circuit; the segmented negative feedback amplification circuit amplifies the received radio frequency signal and outputs the radio frequency signal through two ports of the cross knot type output matching network; a gate DC bias circuit and a drain DC bias circuit are connected with a gate and a drain of a transistor respectively, and are used for providing a working voltage and blocking the radio frequency signal from flowing into a power supply; and the parallel negative feedback circuit realizes a wideband characteristic by connecting a capacitor, an inductor and a microstrip line in parallel between the drain and the gate of the transistor. The application greatly improves a working bandwidth and a circuit design complexity of the circuit, simplifies a structure and reduces a volume of the circuit while improving a noise performance and a gain flatness of the low noise amplifier.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency technology and relates to a parallel negative feedback ultrawideband low noise amplifier based on cross-junction microstrip matching. Background Technology

[0002] In recent years, with the rapid development of communication technology, the next-generation communication technology 5G has entered the commercial stage, placing increasingly higher demands on radio frequency (RF) front-end systems. 5G communication systems have higher requirements for data transmission rates, making bandwidth a key indicator for wireless communication systems. This also means that the bandwidth of the low-noise amplifier (LNOA) in the RF system front-end must be sufficiently large. As a core component of a wireless receiver, the noise performance of the LNOA directly affects the noise characteristics of the entire system, making noise performance another crucial indicator in LNOA design. Therefore, how to design a LNOA with a wide bandwidth while maintaining amplifier noise performance has become a hot topic in the current field of wireless communication systems.

[0003] However, traditional low-noise amplifier designs typically offer good noise performance but suffer from narrow bandwidth. Current broadband topologies have limitations in terms of gain, bandwidth, noise, and power consumption. Traditional topologies also exhibit high circuit design complexity, large circuit size, and difficulty in achieving ultra-wideband performance.

[0004] Therefore, in view of the above-mentioned defects in the current technology, it is necessary to conduct research and improvement to provide a new topology to realize the design of ultra-wideband low-noise amplifier and solve the defects in the existing technology. Summary of the Invention

[0005] To solve the above problems, the technical solution of the present invention is: a parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching, comprising a cross-junction input matching network, a segmented negative feedback amplification circuit, and a cross-junction output matching network, wherein,

[0006] The input of the cross-shaped input matching network is connected to the radio frequency signal, and the output is connected to the segmented negative feedback amplifier circuit. The segmented negative feedback amplifier circuit amplifies the received radio frequency signal and outputs it through the two ports of the cross-shaped output matching network.

[0007] The segmented negative feedback amplifier circuit includes a gate DC bias circuit, a transistor, a drain DC bias circuit, and a parallel negative feedback circuit, wherein...

[0008] The gate DC bias circuit and the drain DC bias circuit are connected to the gate and drain of the transistor, respectively, to provide the operating voltage and block the flow of radio frequency signals into the power supply; the parallel negative feedback circuit achieves broadband characteristics by connecting a capacitor, an inductor and a microstrip line in parallel between the drain and the gate of the transistor.

[0009] Preferably, the cross-junction input matching network adopts a cross-junction microstrip structure, including microstrip lines TL1, TL2, TL3, TL4 and DC blocking capacitor C1; wherein microstrip lines TL1, TL2 and TL3 are series microstrip lines, TL4 is a parallel microstrip line, one end of the four microstrip lines is connected through the same cross-junction, the other end of the first microstrip line TL1 is connected to the DC blocking capacitor C1, the other end of the second microstrip line TL2 is connected to the gate DC bias circuit, the other end of the third microstrip line TL3 is connected to the gate DC bias circuit, and the fourth microstrip line TL4 is terminated with an open circuit.

[0010] Preferably, in the cross-shaped input matching network, microstrip lines TL1 and TL2 are sensitive to low frequencies and suppress low-frequency signals, while microstrip lines TL3 and TL4 are sensitive to high frequencies and suppress high-frequency signals.

[0011] Preferably, the parallel negative feedback circuit includes microstrip lines TL5, TL6, TL7, a feedback resistor R1, and a feedback capacitor C2. One end of microstrip line TL5 is connected to the gate DC bias circuit, the other end of microstrip line TL5 is connected to one end of the feedback resistor R1, the other end of the feedback resistor R1 is connected to one end of microstrip line TL6, the other end of microstrip line TL6 is connected to one end of the DC blocking capacitor C2, the other end of the DC blocking capacitor C2 is connected to one end of microstrip line TL7, and the other end of microstrip line TL7 is connected to the drain DC bias circuit.

[0012] Preferably, the microstrip lines TL5 and TL7 in the parallel negative feedback circuit are used to adjust the size of the parallel negative feedback circuit and provide space for the transistors in terms of structure. The microstrip line TL6 is used to adjust the frequency response of the parallel negative feedback circuit, and the feedback resistor R1 is used to adjust the feedback amount.

[0013] Preferably, the cross-shaped microstrip output matching network includes a microstrip line TL8, a stabilizing resistor R2, and four microstrip lines TL9, TL10, TL11, and TL12 arranged in a cross-shape. One end of microstrip line TL8 is connected to the drain DC bias circuit, and the other end of microstrip line TL8 is connected to one end of the stabilizing resistor R2. The other end of the stabilizing resistor R2 is connected to microstrip line TL9. One end of microstrip lines TL9, TL10, TL11, and TL12 are connected together in a cross-shape. The other end of microstrip line TL10 is connected to the drain DC bias circuit, and the other end of microstrip line TL11 is connected to the DC blocking capacitor C3. The other end of C3 is connected to the output microstrip line, and microstrip line TL12 is a parallel microstrip line with an open-circuit terminal.

[0014] Preferably, the transistor is an InGaAs HEMT transistor, model MGF4941AL.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] This invention provides a parallel negative feedback ultrawideband low-noise amplifier based on a cross-junction microstrip matching structure. By adding a cross-junction topology to the input-output matching network, and using two sets of microstrip lines sensitive to high and low frequencies respectively, impedance transformation over an ultrawideband range is achieved. By connecting a resistor, capacitor, and inductor in parallel between the drain and gate of the transistor, no additional feedback structure is required. This not only reduces the complexity and size of the circuit structure but also effectively suppresses noise, achieving high gain flatness and reducing production costs. Attached Figure Description

[0017] Figure 1 This is a block diagram of a parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to an embodiment of the present invention.

[0018] Figure 2 This is a single-stage circuit diagram of a parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to an embodiment of the present invention.

[0019] Figure 3 This is a circuit diagram of the input matching network of a parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to an embodiment of the present invention.

[0020] Figure 4 This is a circuit diagram of the parallel negative feedback structure of the parallel negative feedback ultrawideband low noise amplifier based on cross-junction microstrip matching according to an embodiment of the present invention.

[0021] Figure 5 This is a complete three-stage circuit diagram of a parallel negative feedback ultrawideband low-noise amplifier based on a cross-junction microstrip matching according to an embodiment of the present invention.

[0022] Figure 6 The figure shows the S-parameter simulation results of the parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to an embodiment of the present invention.

[0023] Figure 7 The figure shows the simulation results of the noise figure of the parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Conversely, this invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the invention as defined in the claims. Furthermore, to provide a better understanding of the invention, certain specific details are described in detail below. However, those skilled in the art will fully understand the invention even without these detailed descriptions.

[0026] To overcome the shortcomings of existing technologies, see Figure 1 The diagram shows the block diagram of the parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching of the present invention. It includes a cross-junction microstrip input matching circuit 10, a segmented parallel negative feedback amplifier circuit 20, and a cross-junction microstrip output matching circuit 30 connected in sequence. The radio frequency signal is connected to the input port of the cross-junction microstrip input matching circuit 10, and the output port is connected to the segmented parallel negative feedback amplifier circuit 20. The segmented parallel negative feedback amplifier circuit 20 amplifies the small radio frequency signal and sends it to the cross-junction microstrip output matching circuit 30. Finally, the radio frequency signal is output through the output port of the cross-junction microstrip output matching circuit 30. The cross-junction microstrip input matching circuit 10 and the cross-junction microstrip output matching circuit 30 not only serve the function of impedance matching, but also have the frequency selection characteristics of a broadband bandpass filter to filter out out-of-band interference signals.

[0027] See Figure 2The diagram shows a circuit diagram of a parallel negative feedback ultrawideband low-noise amplifier based on a cross-junction microstrip matching according to an embodiment of the present invention. The cross-junction microstrip input matching circuit 10 includes microstrip lines TL1, TL2, TL3, TL4, TL1, and a DC blocking capacitor C1. TL1, TL2, and TL3 are series microstrip lines, and TL4 is a parallel microstrip line. One end of each of the four microstrip lines is connected through the same cross-junction. The other end of the first microstrip line TL1 is connected to the DC blocking capacitor, the other end of the second microstrip line TL2 is connected to the gate DC bias circuit 22, the other end of the third microstrip line TL3 is connected to the gate DC bias circuit 22, and the fourth microstrip line TL4 is a parallel microstrip line with open-circuit termination. The segmented parallel negative feedback amplifier circuit 20 achieves broadband characteristics by connecting a capacitor, an inductor, and a microstrip line in parallel between the drain and gate of transistor 21. The microstrip line includes microstrip lines TL5, TL6, and TL7, a feedback resistor R1, and a feedback capacitor C2. One end of microstrip line TL5 is connected to the gate DC bias circuit 22, and the other end of microstrip line TL5 is connected to the feedback resistor R1. The other end of the feedback resistor R1 is connected to one section of microstrip line TL6, and the other end of microstrip line TL6 is connected to the DC blocking capacitor C2. The other end of the DC blocking capacitor C2 is connected to microstrip line TL7, and the other end of microstrip line TL7 is connected to the drain DC bias circuit 23. The cross-junction microstrip output matching circuit 30 includes a stabilizing resistor R2 and four microstrip lines symmetrically arranged vertically and horizontally. One end of microstrip line TL8 is connected to the drain DC bias circuit 23, and the other end of microstrip line is connected to one end of the stabilizing resistor R2. The other end of the stabilizing resistor R2 is connected to the matching microstrip line TL9. One segment of matching microstrip lines TL9, TL10, TL11 and TL12 are connected together. The other end of microstrip line TL10 is connected to the drain DC bias circuit 23. The other end of microstrip line TL11 is connected to the DC blocking capacitor C3. The other end of C3 is connected to the output microstrip line. Microstrip line TL12 is a parallel microstrip line with an open-circuit terminal.

[0028] See Figure 3 The diagram shows the drain-parallel negative feedback topology of a parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to an embodiment of the present invention. For low-order systems, the product of gain and bandwidth is a constant, and the gain is:

[0029]

[0030] Among them, w p and A I These are the polar angle frequency and intermediate frequency gain. When a feedback network is introduced into the system, the feedback gain is:

[0031]

[0032] ω pf =ω p(1+k f A I )

[0033]

[0034] F = 1 + k f A I It is the feedback depth of the LNA, k f It is the feedback constant, A П It is the broadband gain, which increases with k f The improvement, A П Decrease and ω pf The increase determines the broadband characteristics of the negative feedback amplifier topology.

[0035] Assuming the gate-source capacitance of the transistor is infinite, the input-output impedance relationship is as follows:

[0036]

[0037]

[0038] Among them, R s R is the source impedance. L R is the load impedance. f It is the feedback resistor, R1 is the resistor connected to the source terminal of the transistor, g m This refers to the transconductance of the transistor. If both the source and load impedances are equal to R0, then when the input and output impedances are simultaneously matched, both Rin and Rout should be equal to R0. Combining this with 6 and 7, we can obtain:

[0039] (1+g m R1)R f =g m R0 2

[0040] See Figure 4 The diagram shows the lumped parameter component model and transmission line model of the parallel negative feedback ultra-wideband low-noise amplifier matching network based on a cross-shaped microstrip matching according to an embodiment of the present invention. Considering the parasitic effects of capacitors and inductors, the capacitors and inductors need to be converted into microstrip lines in the matching circuit. Based on the transfer matrices corresponding to series inductors and capacitors, and parallel inductors and capacitors, the transfer matrix of this circuit can be obtained from two-port theory as follows:

[0041]

[0042] According to two-port theory, the transfer matrix of a lossless transmission line of length l and characteristic impedance Z0 is:

[0043]

[0044] Where β is the transmission constant. When the characteristic impedance Z0 is relatively high, the transfer matrix of the transmission line is consistent with the form of the series inductor transfer matrix. When the characteristic impedance Z0 is relatively low, the transfer matrix of the transmission line is consistent with the form of the parallel capacitor transfer matrix. Therefore, a high-impedance microstrip transmission line can be used to represent the equivalent series inductor, and a low-impedance transmission line can be used to represent the equivalent parallel capacitor. The formula for calculating the transmission line length is as follows:

[0045]

[0046]

[0047] Among them, Z H Z is the characteristic impedance of a high-impedance transmission line. L The characteristic impedance of a low-impedance transmission line is used to calculate the transmission line width, which is affected by the characteristic impedance. The formula is as follows:

[0048]

[0049] Wherein, the free-space wave impedance η0 = 120π, the coefficient u = W / h, W is the microstrip line width, h is the dielectric thickness, and ε eff The relative permittivity,

[0050]

[0051] Using the above formulas, the inductors and capacitors used in the cross-junction microstrip matching structure can be equivalently replaced with microstrip lines.

[0052] See Figure 5 The diagram shows a complete three-stage cascaded circuit of a parallel negative feedback ultrawideband low-noise amplifier based on a cross-junction microstrip matching according to an embodiment of the present invention. The interstage circuits are connected by capacitors. According to the transistor's technical manual, the first stage circuit ensures the noise performance of the low-noise amplifier, while the second and third stage circuits pursue the overall gain of the circuit. All three stages adopt a parallel negative feedback structure to ensure the overall gain flatness of the circuit.

[0053] See Figure 6-7 The figure shows the S-parameters and noise figure of the parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to an embodiment of the present invention, obtained by simulation. The designed power amplifier has a working bandwidth of 2-10GHz, and the input and output return losses are both less than -15dB within the working frequency band. The gain is greater than 30dB, the in-band gain fluctuation is less than 5dB, and it is absolutely stable both in and out of the band. The noise figure is less than 1.78dB, achieving an ultrawide working frequency band, good gain flatness and noise suppression characteristics.

[0054] Regardless of the detailed description above, there are many ways to implement this invention. The embodiments described in this specification are merely a few specific examples of the invention. All equivalent transformations or modifications made in accordance with the spirit and essence of this invention should be covered within the scope of protection of this invention.

[0055] The detailed description of the embodiments of the present invention above is not exhaustive or intended to limit the invention to the specific forms described above. While specific embodiments and examples of the invention have been described above for illustrative purposes, those skilled in the art will recognize that various equivalent modifications can be made within the scope of the invention.

[0056] While the foregoing description has described specific embodiments of the invention and the intended optimal mode, the invention can be implemented in many ways, regardless of the level of detail described above. The details of the circuit structure and its control method described above can be varied considerably in their implementation, yet they are still included within the scope of the invention disclosed herein.

[0057] As stated above, it should be noted that the specific terminology used in describing certain features or aspects of the invention should not be used to indicate that the term is being redefined herein to limit certain particular features, characteristics, or aspects of the invention associated with that term. In short, the terminology used in the appended claims should not be construed as limiting the invention to the specific embodiments disclosed in the specification, unless these terms are expressly defined in the foregoing detailed description. Therefore, the actual scope of the invention includes not only the disclosed embodiments but also all equivalents implemented or practiced under the claims.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching, characterized in that, This includes a cross-junction input matching network, a segmented negative feedback amplifier circuit, and a cross-junction output matching network, among which... The input of the cross-shaped input matching network is connected to the radio frequency signal, and the output is connected to the segmented negative feedback amplifier circuit. The segmented negative feedback amplifier circuit amplifies the received radio frequency signal and outputs it through the two ports of the cross-shaped output matching network. The segmented negative feedback amplifier circuit includes a gate DC bias circuit, a transistor, a drain DC bias circuit, and a parallel negative feedback circuit, wherein... The gate DC bias circuit and the drain DC bias circuit are connected to the gate and drain of the transistor, respectively, to provide the operating voltage and block the flow of radio frequency signals into the power supply; the parallel negative feedback circuit achieves broadband characteristics by connecting a capacitor, an inductor and a microstrip line in parallel between the drain and the gate of the transistor. The cross-junction input matching network adopts a cross-junction microstrip structure, including microstrip lines TL1, TL2, TL3, TL4 and DC blocking capacitor C1; wherein microstrip lines TL1, TL2 and TL3 are series microstrip lines, TL4 is parallel microstrip line, one end of the four microstrip lines is connected through the same cross-junction, the other end of the first microstrip line TL1 is connected to the DC blocking capacitor C1, the other end of the second microstrip line TL2 is connected to the gate DC bias circuit, the other end of the third microstrip line TL3 is connected to the gate DC bias circuit, and the fourth microstrip line TL4 is terminated with an open circuit; The parallel negative feedback circuit includes microstrip lines TL5, TL6, TL7, feedback resistor R1, and feedback capacitor C2. One end of microstrip line TL5 is connected to the gate DC bias circuit, the other end of microstrip line TL5 is connected to one end of feedback resistor R1, the other end of feedback resistor R1 is connected to one end of microstrip line TL6, the other end of microstrip line TL6 is connected to one end of DC blocking capacitor C2, the other end of DC blocking capacitor C2 is connected to one end of microstrip line TL7, and the other end of microstrip line TL7 is connected to the drain DC bias circuit. The cross-shaped microstrip output matching network includes a microstrip line TL8, a stabilizing resistor R2, and four microstrip lines TL9, TL10, TL11, and TL12 arranged in a cross-shape. One end of microstrip line TL8 is connected to the drain DC bias circuit, and the other end of microstrip line TL8 is connected to one end of the stabilizing resistor R2. The other end of the stabilizing resistor R2 is connected to microstrip line TL9. One end of microstrip lines TL9, TL10, TL11, and TL12 are connected together in a cross-shape. The other end of microstrip line TL10 is connected to the drain DC bias circuit, and the other end of microstrip line TL11 is connected to the DC blocking capacitor C3. The other end of C3 is connected to the output microstrip line, and microstrip line TL12 is a parallel microstrip line with an open-circuit termination.

2. The parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to claim 1, characterized in that, In the cross-shaped input matching network, microstrip lines TL1 and TL2 are sensitive to low frequencies and suppress low-frequency signals, while microstrip lines TL3 and TL4 are sensitive to high frequencies and suppress high-frequency signals.

3. The parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to claim 1, characterized in that, The microstrip lines TL5 and TL7 in the parallel negative feedback circuit are used to adjust the size of the parallel negative feedback circuit and provide space for the transistors in terms of structure. The microstrip line TL6 is used to adjust the frequency response of the parallel negative feedback circuit, and the feedback resistor R1 is used to adjust the feedback amount.

4. The parallel negative feedback ultrawideband low-noise amplifier based on cross-junction microstrip matching according to claim 1, characterized in that, The transistor is an InGaAs HEMT transistor, model MGF4941AL.

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