Wideband low noise amplifier

Abstract

The present invention relates to a wideband low noise amplifier and, more specifically, a wideband low noise amplifier characterized by having a first auxiliary amplifier and a second auxiliary amplifier added to an existing wideband low noise amplifier and operating on signals from each amplifier to simultaneously cancel both the noise generated by the main amplifier and the noise generated by the auxiliary amplifiers and thereby improve the overall amplifier noise index characteristics.

Description

Wideband low noise amplifier

[0001] The present invention relates to a wideband low-noise amplifier, and more particularly, to a wideband low-noise amplifier capable of improving noise figure characteristics by canceling out noise generated in the amplifier.

[0002]

[0003] Recently, with the advancement of wireless communication technology, the demand for high-performance communication with high frequency and high sensitivity has continuously expanded, and accordingly, the importance of low-noise amplifiers applied to various communication systems is increasing.

[0004] In general, low-noise amplifiers have applied noise cancellation technology using common-gate (CG) amplifiers with wideband characteristics or resistive feedback.

[0005] In the case of a conventional wideband low-noise amplifier, a common-source (CS) amplifier, which is an auxiliary amplifier, is connected to the main amplifier to cancel out the noise generated by the main amplifier, but since the noise generated by the added auxiliary amplifier cannot be canceled out, additional noise contribution occurs, and this limits the improvement of the noise figure characteristics of the overall amplifier.

[0006]

[0007] [Prior Art Literature]

[0008] [Patent Document]

[0009] Korean Patent Publication No. 10-1038854 (“Broadband Low-Noise Amplifier,” published on May 27, 2011)

[0010]

[0011] The present invention has been devised to solve the above-mentioned problems, and the wideband low-noise amplifier according to the present invention relates to a wideband low-noise amplifier that can improve the noise figure characteristics of the overall amplifier by simultaneously canceling out noise generated from the auxiliary amplifier as well as noise generated from the main amplifier by adding an auxiliary amplifier to an existing wideband low-noise amplifier.

[0012]

[0013] In order to solve the above-described problem, a wideband low-noise amplifier according to one embodiment of the present invention is a wideband low-noise amplifier connected to a signal source unit that includes an internal resistance and provides a source signal, the wideband low-noise amplifier including a main amplifier, a first auxiliary amplifier, and a second auxiliary amplifier that receive the source signal in parallel and output an amplified signal respectively, a noise feedback circuit connected in parallel to the input / output of the first auxiliary amplifier, and a signal combining unit that is connected to the outputs of the main amplifier, the first auxiliary amplifier, and the second auxiliary amplifier and calculates the output signals of the main amplifier, the first auxiliary amplifier, and the second auxiliary amplifier, wherein the output signal of the main amplifier and the output signals of the first auxiliary amplifier and the second auxiliary amplifier are inverted with each other, and the output signals of the first auxiliary amplifier and the second auxiliary amplifier are non-inverted with each other, and the noise feedback circuit is characterized in that it includes a feedback resistor that satisfies a noise cancellation condition, which is a condition in which noise of the main amplifier and noise of the first auxiliary amplifier are canceled at the output of the signal combining unit.

[0014] In addition, the main amplifier is characterized in that it receives the source signal and outputs a non-inverted amplified signal, and the first auxiliary amplifier and the second auxiliary amplifier receive the source signal and output an inverted amplified signal.

[0015] In addition, the main amplifier is characterized in that the source and drain are connected to the signal source section and the signal coupling section, respectively, and noise is generated in which the phases of the input and output of the main amplifier are 180° different due to the internal resistance.

[0016] In addition, the first auxiliary amplifier and the second auxiliary amplifier are characterized in that they are common source amplifiers in which the gate and the drain are connected to the signal source section and the signal coupling section, respectively.

[0017] In addition, the signal combining unit is characterized by adding the output signals of the first auxiliary amplifier and the second auxiliary amplifier, and subtracting the added output signal and the output signal of the main amplifier.

[0018] In addition, the wideband low-noise amplifier is characterized by including a first pull-up resistor having one end connected to a power source and the other end connected to the output of the main amplifier, a second pull-up resistor having one end connected to a power source and the other end connected to the output of the first auxiliary amplifier, and a third pull-up resistor having one end connected to a power source and the other end connected to the output of the second auxiliary amplifier.

[0019] In addition, the noise feedback circuit is characterized in that it includes a feedback resistor having one end and the other end connected to the input and output of the first auxiliary amplifier, respectively, and having the same resistance value as the first pull-up resistor.

[0020]

[0021] According to the wideband low-noise amplifier according to one embodiment of the present invention as described above, there is an effect of being able to cancel out not only noise generated from the main amplifier but also noise generated from the auxiliary amplifier.

[0022] Additionally, it has the effect of improving the noise figure characteristics of the overall amplifier.

[0023]

[0024] FIG. 1 is a schematic diagram showing a wideband low-noise amplifier according to one embodiment of the present invention.

[0025] Fig. 2 is a circuit diagram showing a wideband low-noise amplifier according to one embodiment of the present invention.

[0026] FIG. 3 is an exemplary diagram showing a noise cancellation process occurring in a main amplifier of a wideband low-noise amplifier according to one embodiment of the present invention.

[0027] FIG. 4 is an exemplary diagram showing a noise cancellation process occurring in a first auxiliary amplifier of a wideband low-noise amplifier according to one embodiment of the present invention.

[0028] Fig. 5 is a graph showing simulation results for the gain of a wideband low-noise amplifier according to one embodiment of the present invention.

[0029] Fig. 6 is a graph showing the noise figure of a wideband low-noise amplifier according to one embodiment of the present invention.

[0030]

[0031] The above-described objects, features, and advantages of the present invention will become more apparent through the following examples taken in conjunction with the accompanying drawings. The specific structural and functional descriptions below are merely illustrative for the purpose of explaining embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms and should not be construed as limited to the embodiments described in this specification or application. Since embodiments according to the concept of the present invention may have various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in this specification or application. However, this is not intended to limit embodiments according to the concept of the present invention to specific disclosed forms, but should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention. Terms such as "first and" or "second" may be used to describe various components, but the components are not limited to the terms. The above terms are used solely for the purpose of distinguishing one component from another, for example, without departing from the scope of the rights according to the concept of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. When a component is referred to as being connected or coupled to another component, it should be understood that it may be directly connected or coupled to the other component, but there may also be other components in between. On the other hand, when a component is referred to as being directly connected or coupled to another component, it should be understood that there are no other components in between. Other expressions used to describe the relationship between components, such as "between" and "directly between" or "adjacent to" and "directly adjacent to", should be interpreted similarly.The terminology used herein is used solely to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. It should be understood that the terms "comprise" and "have" used herein indicate the presence of a described feature, number, step, operation, component, part, or combination thereof, and do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein. Hereinafter, the present invention will be described in detail by describing a preferred embodiment of the present invention with reference to the accompanying drawings. The same reference numerals in each drawing represent the same parts.

[0032]

[0033] FIG. 1 is a schematic diagram illustrating a wideband low-noise amplifier according to one embodiment of the present invention, and FIG. 2 is a circuit diagram illustrating a wideband low-noise amplifier according to one embodiment of the present invention. With reference to FIGS. 1 and 2, the wideband low-noise amplifier according to one embodiment of the present invention will be described in detail.

[0034]

[0035] A wideband low-noise amplifier (1000) according to one embodiment of the present invention is a wideband low-noise amplifier that includes an internal resistor (11) and is connected to a signal source unit (10) that provides a source signal, and may include a main amplifier (100), a first auxiliary amplifier (200), a second auxiliary amplifier (300), a noise feedback circuit (400), and a signal coupling unit (500), as shown in FIG. 1.

[0036] Let's take a closer look at each component:

[0037] The above main amplifier (100), first auxiliary amplifier (200), and second auxiliary amplifier (300) can receive the source signal in parallel and output an amplified signal, respectively.

[0038] In detail, the main amplifier (100) can receive the source signal and output a non-inverted amplified signal, and the first auxiliary amplifier (200) and the second auxiliary amplifier (300) can receive the source signal and output an inverted amplified signal.

[0039] The main amplifier (100) may be a common gate amplifier in which the source and drain are respectively connected to the signal source section (10) and the signal coupling section (500), and noise is generated in which the phases of the input and output of the main amplifier (100) are 180° different by the internal resistance (11), and the first auxiliary amplifier (200) and the second auxiliary amplifier (300) may be common source amplifiers in which the gate and drain are respectively connected to the signal source section (10) and the signal coupling section (500).

[0040] In detail, the signal source unit (10) may be connected to the source of the main amplifier (100), the gate of the first auxiliary amplifier (200), and the gate of the second auxiliary amplifier (300), and the signal coupling unit (500) may be connected to the drain of the main amplifier (100), the drain of the first auxiliary amplifier (200), and the drain of the second auxiliary amplifier (300).

[0041] The present invention is not limited to the configuration of the main amplifier (100), the first auxiliary amplifier (200) and the second auxiliary amplifier (300), and in the case of BJT, they may be a common base amplifier and a common emitter amplifier.

[0042] The above noise feedback circuit (400) may be connected in parallel to the input and output of the first auxiliary amplifier (200). At this time, the noise feedback circuit (400) may include a feedback resistor (410) that satisfies a noise cancellation condition, which is a condition in which the noise of the main amplifier (100) and the noise of the first auxiliary amplifier (200) are canceled out at the output of the signal combining unit (500).

[0043] In detail, the noise feedback circuit (400) may include a feedback resistor (410) having one end and the other end connected to the input and output of the first auxiliary amplifier (200), respectively, and having the same resistance value as the first pull-up resistor (600), which will be described in detail later. Here, the present invention is not limited to the configuration of the noise feedback, and may be included in the amplifier or connected to the amplifier as a separate configuration.

[0044] The above signal coupling unit (500) is connected to the outputs of the main amplifier (100), the first auxiliary amplifier (200), and the second auxiliary amplifier (300) and can calculate the output signals of the main amplifier (100), the first auxiliary amplifier (200), and the second auxiliary amplifier (300).

[0045] In detail, the signal combining unit (500) can add the output signals of the first auxiliary amplifier (200) and the second auxiliary amplifier (300), and subtract the added output signal from the output signal of the main amplifier (100).

[0046] A wideband low-noise amplifier (1000) according to one embodiment of the present invention may include a first pull-up resistor (600) having one end connected to a power source and the other end connected to an output of the main amplifier (100), a second pull-up resistor (700) having one end connected to a power source and the other end connected to an output of the first auxiliary amplifier (200), and a third pull-up resistor (800) having one end connected to a power source and the other end connected to an output of the second auxiliary amplifier (300).

[0047] In this way, the wideband low-noise amplifier (1000) according to one embodiment of the present invention can cancel out not only the noise generated in the main amplifier (100), but also the noise generated in the first auxiliary amplifier (200) through the configuration of the main amplifier (100), the first auxiliary amplifier (200), the second auxiliary amplifier (300), the noise feedback circuit (400), and the signal coupling unit (500).

[0048]

[0049] FIG. 3 is an exemplary diagram illustrating a process of canceling noise generated in a main amplifier of a wideband low-noise amplifier according to an embodiment of the present invention, and FIG. 4 is an exemplary diagram illustrating a process of canceling noise generated in a first auxiliary amplifier of a wideband low-noise amplifier according to an embodiment of the present invention. The noise canceling process of a wideband low-noise amplifier according to an embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4.

[0050]

[0051] A wideband low-noise amplifier (1000) according to one embodiment of the present invention adds output signals of a first auxiliary amplifier (200) and a second auxiliary amplifier (300) by a signal combining unit (500), and subtracts the added signals from the output signal of the main amplifier (100), thereby canceling out noise of the main amplifier (100) and noise of the first auxiliary amplifier (200).

[0052]

[0053] First, let's look at the process of canceling out the noise of the main amplifier (100).

[0054] Noise of the above main amplifier (100) ) as shown in Fig. 3, noise with a phase difference of 180° is formed at the input and output of the main amplifier (100) by the internal resistance (11) included in the signal source section (10), and the noise formed at the input of the main amplifier (100) is input to the first auxiliary amplifier (200) and the second auxiliary amplifier (300), and each inverted noise is output.

[0055] Thereafter, each of the inverted noises is added through the signal combining unit (500), and the added noise and the noise formed at the output of the main amplifier (100) are subtracted through the signal combining unit (500), thereby canceling out the noise of the main amplifier (100).

[0056] Here, the condition for canceling the noise of the main amplifier (100) can be calculated as in the following mathematical expression 1.

[0057]

[0058]

[0059]

[0060] (Here, is the channel noise value of the main amplifier (100),

[0061] is the input resistance value for the internal resistance included in the signal source section (10),

[0062] is the first pull-up resistor (600) value,

[0063] is the node voltage value of the input terminals of the main amplifier (100), the first auxiliary amplifier (200) and the second auxiliary amplifier (300),

[0064] is the node voltage value of the output terminal of the first auxiliary amplifier (200) and the second pull-up resistor (700),

[0065] is the node voltage value of the output terminal of the second auxiliary amplifier (300) and the third pull-up resistor (800).

[0066]

[0067] Next, let's look at the process of canceling out the noise of the first auxiliary amplifier (200).

[0068] Noise of the above first auxiliary amplifier (200) ) is fed back to the input of the first auxiliary amplifier (200) by a noise feedback circuit connected in parallel to the input / output of the first auxiliary amplifier (200), and the fed back noise is input to the main amplifier (100) and the second auxiliary amplifier (300), so that non-inverted noise and inverted noise are output, respectively.

[0069] Thereafter, the noise of the first auxiliary amplifier (200) and the inverted noise of the second auxiliary amplifier (300) are added through the signal combining unit (300), and the added noise and the non-inverted noise of the main amplifier (100) are subtracted through the signal combining unit (300), thereby canceling out the noise of the first auxiliary amplifier (200).

[0070] Here, the condition for canceling the noise of the first common source amplifier (220) can be calculated as in the following mathematical expression 2.

[0071]

[0072]

[0073]

[0074] (Here, is the channel noise value of the first auxiliary amplifier (200),

[0075] is the first pull-up resistor (600) value, is the value of the third pull-up resistor (600),

[0076] is the node resistance value of the output terminal of the first auxiliary amplifier (200) and the second pull-up resistor (700),

[0077] is the node voltage value of the input terminals of the main amplifier (100), the first auxiliary amplifier (200) and the second auxiliary amplifier (300),

[0078] is the node voltage value of the output terminal of the first auxiliary amplifier (200) and the second pull-up resistor (700),

[0079] is the transconductance value of the main amplifier (100),

[0080] is the transconductance value of the second auxiliary amplifier (300).

[0081]

[0082] The above noise feedback circuit (400) may include a feedback resistor (410) that simultaneously satisfies a condition in which the noise of the main amplifier (100) is canceled and a condition in which the noise of the first auxiliary amplifier (200) is canceled. At this time, the noise feedback circuit (400) may include a feedback resistor (410) having the same resistance value as the first pull-up resistor (600).

[0083] In detail, by applying the mathematical expression 3 below, a relational expression that simultaneously satisfies the noise cancellation condition of the common gate amplifier (210) and the noise cancellation condition of the first common source amplifier (220) can be derived.

[0084]

[0085]

[0086]

[0087] (Here, is the input impedance value of the main amplifier (100),

[0088] is the input impedance value of the first auxiliary amplifier (200) and the second auxiliary amplifier (300),

[0089] is the internal resistance (11) value included in the signal source section (10).

[0090]

[0091] The relationship derived by applying the above mathematical formula 3 is as shown in the following mathematical formula 4.

[0092]

[0093]

[0094] (Here, is the first pull-up resistor (600) value,

[0095] is the value of the feedback resistor (410) connected to the first auxiliary amplifier (200).

[0096]

[0097] Hereinafter, with reference to FIGS. 4 and 5, let us look at the simulation results of a wideband low-noise amplifier (1000) according to one embodiment of the present invention.

[0098] Fig. 4 is a graph showing simulation results for the gain of a wideband low-noise amplifier according to one embodiment of the present invention.

[0099] In the simulation results of Fig. 4, the horizontal axis represents the frequency of the input RF signal, and the vertical axis represents the gain (Gain, S21 parameter). In addition, V1 represents the gain for the output signal of the main amplifier (100), V2+V3 represent the gain for the sum signal in which the output signal of the first auxiliary amplifier (200) and the output signal of the second auxiliary amplifier (300) are added, and Vout represents the gain for the signal output by the signal combining unit (300). Referring to Fig. 4, it can be seen that the overall gain of the wideband low noise amplifier (1000) according to one embodiment of the present invention has a range of about 14 dB to 21 dB, and a gain improvement of about 4 dB is shown compared to the gain of V2+V3.

[0100] Fig. 5 is a graph showing the noise figure of a wideband low-noise amplifier according to one embodiment of the present invention.

[0101] In the simulation results of Fig. 5, the horizontal axis represents the frequency of the input RF, and the vertical axis represents the noise figure. In addition, V1 represents the noise figure for the output terminal of the main amplifier (100), V2+V3 represent the noise figure of the sum signal output terminal of the output signal of the first auxiliary amplifier (200) and the output signal of the second auxiliary amplifier (300), and Vout represents the noise figure for the output terminal of the signal combining unit (300). Referring to Fig. 5, it can be seen that the overall noise figure of the wideband low noise amplifier (1000) according to one embodiment of the present invention has a range of about 2 dB to 8 dB, and an improvement in the noise figure of about 2 dB is shown compared to the noise figure of V2+V3.

[0102] Accordingly, referring to the simulation results of FIGS. 4 and 5, the wideband low-noise amplifier (1000) according to one embodiment of the present invention has the effect of improving the gain for the final signal, and although there is somewhat large noise in each amplifier, the noise figure at the final output stage is improved.

[0103]

[0104] In summary, the wideband low-noise amplifier (1000) according to one embodiment of the present invention has the effect of being able to mutually cancel out noise generated from the auxiliary amplifier as well as noise generated from the main amplifier by adding an auxiliary amplifier.

[0105]

[0106] Although preferred embodiments of the present invention have been described above, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but rather to explain it. Therefore, the technical spirit of the present invention includes not only each disclosed embodiment but also combinations of disclosed embodiments, and further, the scope of the technical spirit of the present invention is not limited by these embodiments. Furthermore, those skilled in the art to which the present invention pertains may make numerous changes and modifications to the present invention without departing from the spirit and scope of the appended claims, and all such appropriate changes and modifications should be considered as equivalents and falling within the scope of the present invention.

[0107]

[0108] [Explanation of symbols]

[0109] 10: Signal source section

[0110] 11: Internal resistance

[0111] 100: Main amplifier

[0112] 200: 1st auxiliary amplifier

[0113] 300: Second auxiliary amplifier

[0114] 400: Noise feedback circuit

[0115] 410: Feedback resistor

[0116] 500: Signal coupling unit

[0117] 600: 1st pull-up resistor

[0118] 700: Second pull-up resistor

[0119] 800: 3rd pull-up resistor

[0120] 1000: Wideband Low Noise Amplifier

Claims

1. In a wideband low noise amplifier connected to a signal source section that includes an internal resistance and provides a source signal, A main amplifier, a first auxiliary amplifier, and a second auxiliary amplifier that receive the source signal in parallel and output an amplified signal respectively; A noise feedback circuit connected in parallel to the input and output of the first auxiliary amplifier; and A signal coupling unit connected to the outputs of the main amplifier, the first auxiliary amplifier, and the second auxiliary amplifier and calculating the output signals of the main amplifier, the first auxiliary amplifier, and the second auxiliary amplifier; The output signal of the main amplifier and the output signals of the first auxiliary amplifier and the second auxiliary amplifier are inverted from each other, and the output signals of the first auxiliary amplifier and the second auxiliary amplifier are non-inverted from each other. The above noise feedback circuit, Including a feedback resistor that satisfies a noise cancellation condition, which is a condition in which the noise of the main amplifier and the noise of the first auxiliary amplifier are canceled out at the output of the signal coupling unit. A wideband low noise amplifier featuring .

2. In paragraph 1, The above main amplifier, It receives the above source signal and outputs a non-inverted amplified signal, The above first auxiliary amplifier and second auxiliary amplifier, Inputting the above source signal and outputting an inverted amplified signal A wideband low noise amplifier featuring .

3. In paragraph 1, The above main amplifier, A common gate amplifier in which the source and drain are respectively connected to the signal source section and the signal coupling section, and noise is generated in which the phase of the input and output of the main amplifier is 180° different due to the internal resistance. A wideband low noise amplifier featuring .

4. In paragraph 1, The above first auxiliary amplifier and second auxiliary amplifier, A common source amplifier in which the gate and drain are respectively connected to the signal source section and signal coupling section. A wideband low noise amplifier featuring .

5. In paragraph 1, The above signal coupling unit is, Adding the output signals of the first auxiliary amplifier and the second auxiliary amplifier, and subtracting the added output signal and the output signal of the main amplifier. A wideband low noise amplifier featuring .

6. In paragraph 1, The above wideband low noise amplifier, A first pull-up resistor, one end of which is connected to the power supply and the other end is connected to the output of the main amplifier; A second pull-up resistor, one end of which is connected to the power supply and the other end is connected to the output of the first auxiliary amplifier; and One end is connected to the power supply and the other end includes a third pull-up resistor connected to the output of the second auxiliary amplifier. A wideband low noise amplifier featuring .

7. In paragraph 6, The above noise feedback circuit, Including a feedback resistor having the same resistance value as the first pull-up resistor A wideband low noise amplifier featuring .

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