KR20220157768A - Low noise amplifier - Google Patents

Abstract

The present invention relates to a low noise amplifier. The low noise amplifier according to one embodiment of the present invention comprises: a first transistor part comprising a first transistor electrically connected to an input end and an output end and a first transmission line interposed between the first transistor and the output end; and a second transistor part comprising a second transistor electrically connected to the input end and the output end and a second transmission line interposed between the input end and the second transistor, wherein the first transistor part and the second transistor part are connected in parallel. Therefore, the present invention is capable of having a high transmission output power.

Description

Low Noise Amplifier {LOW NOISE AMPLIFIER}

The present invention relates to a low noise amplifier, and more particularly, to a low noise amplifier that improves maximum input power in an ultra-high frequency band and minimizes a reduction in noise figure accordingly.

For long-distance communication in an ultra-high frequency band expected to be utilized in communication and battlefield, a system having high transmission output power is required. When the output power of the transmitter increases, the power flowing into the low noise amplifier of the transmit/receive system becomes relatively large. As the unnecessary transmit output signal flows into the LNO, the range of the LNO that can receive a signal is reduced, and in the worst case, the LNO is saturated and can reach a state where reception is impossible. In order to overcome this problem, a duplexer, a diplexer, or a switch is placed between the transmitter and the receiver to improve isolation characteristics or to increase the maximum power that can be processed by the low noise amplifier itself. method is being studied.

Korean Patent Registration No. 0157206 (July 28, 1998) relates to a low-noise amplifier, and a circuit of a low-noise amplifier according to an embodiment of the present invention includes an input matching unit of an input stage, an output matching unit of an output stage, and the input matching unit A common source transistor and a common gate transistor connected in series between output matching means, a first inductor connected between the source and ground of the common source transistor, and connected between a common point of the common source transistor and the common gate transistor and an output terminal of the common gate transistor. It consists of a second inductor. Therefore, since the Γ _opt and G _max points can be made closer together, noise and input gain can be simultaneously matched, performance can be improved.

However, in the case of using a single transistor as described above, when the transistor width is increased to increase the maximum input power of the low noise amplifier, there is a problem in that the noise figure of the low noise amplifier is attenuated.

A technical problem to be solved by the present invention is to provide a low noise amplifier with improved maximum input power for long-distance communication in an ultra-high frequency band.

In order to solve the above technical problem, an embodiment of the present invention includes a first transistor electrically connected to an input terminal and an output terminal, and a first transmission line interposed between the first transistor and the output terminal. A first transistor unit including, and a second transistor unit including a second transistor electrically connected to the input terminal and the output terminal, and a second transmission line interposed between the input terminal and the second transistor, wherein the first transistor unit and the second transistor unit are parallel to each other. A connected, low-noise amplifier is provided.

In one embodiment, the first transistor and the second transistor may be NMOS transistors.

In one embodiment, a noise figure of the first transistor may be lower than that of the second transistor.

In one embodiment, the width of the first transistor may be wider than that of the second transistor.

In one embodiment, the width of the second transistor may be 60% to 90% of the width of the first transistor.

In one embodiment, the width of the first transistor may be 20±1 μm, and the width of the second transistor may be 15±1 μm.

In one embodiment, the first transmission line has an inductance component in a high frequency band, and minimizes a phase difference between a first output signal output from the first transistor unit and a second output signal output from the second transistor unit. can

In one embodiment, the length of the first transmission line may be determined to minimize a phase difference between the first output signal and the second output signal.

In an embodiment, a width of the first transmission line may be determined to minimize a phase difference between the first output signal and the second output signal.

In one embodiment, the second transmission line has an inductance component in a high frequency band, and the second transmission line includes a first output signal output from the first transistor unit and a second output signal output from the second transistor unit. A level of the second output signal may be adjusted to have a preset signal ratio.

In one embodiment, the preset signal ratio may be determined according to a ratio of noise characteristics of the first transistor and noise characteristics of the second transistor.

In one embodiment, the length of the second transmission line may be determined so that the first output signal and the second output signal have the preset signal ratio.

In one embodiment, the width of the second transmission line may be determined such that the first output signal and the second output signal have the preset signal ratio.

A low noise amplifier according to an embodiment of the present invention includes a plurality of first transistor units including a first transistor electrically connected to an input terminal and an output terminal, and a first transmission line interposed between the first transistor and the output terminal, and the a plurality of second transistor units including a second transistor electrically connected to an input terminal and an output terminal, and a second transmission line interposed between the input terminal and the second transistor, wherein the first transistor units and the second transistor units can be connected in parallel.

A low noise amplifier according to an exemplary embodiment of the present invention uses a transistor combination structure, and has high maximum input power, while noise characteristics are not attenuated. Therefore, it can be utilized in a long-distance communication system in the ultra-high frequency band having high transmission output power.

The technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description below.

1 is a circuit diagram showing a low noise amplifier according to an embodiment of the present invention.
2 is a diagram illustrating a low noise amplifier including a plurality of transistors according to one embodiment of the present invention.
3 is a graph showing the relationship between transistor width and noise characteristics of a low noise amplifier according to the prior art.
4 is a graph showing a relationship between a transistor width and a maximum input power of a low noise amplifier according to the prior art.
5 is a diagram illustrating a minimum noise characteristic value and an input/output matching impedance value of a low noise amplifier according to an embodiment of the present invention.
6a to 6c are gain graphs of low noise amplifiers having different transistor widths according to the prior art.
7 is a gain graph of a low noise amplifier according to an embodiment of the present invention.

While the present invention is susceptible to various modifications and variations, specific embodiments thereof are illustrated and shown in the drawings, which will be described in detail below. However, this is not intended to limit the invention to the particular form disclosed, but rather the invention includes all modifications, equivalents and substitutions consistent with the spirit of the invention as defined by the claims.

The invention can be presented as functional block structures and various processing steps. These functional blocks may be implemented with any number of hardware or/and software components that perform specific functions. For example, the present invention relates to integrated circuit components such as memory, processing, logic, look-up tables, etc., which can execute various functions under the control of one or more microprocessors or other control devices. can be hired

In addition, the present invention may employ conventional techniques for electronic environment setting, signal processing, and/or data processing. Terms such as "part", "element", "means", and "component" may be used broadly, and the components of the present invention are not limited to mechanical and physical components. The term may include a meaning of a series of software routines in connection with a processor or the like.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being “on” another element, it may be directly on the other element or intervening elements may exist. .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and/or blocks, these elements, components, regions, layers and/or blocks It will be understood that one should not be limited by these terms.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. Hereinafter, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

1 is a circuit diagram showing a low noise amplifier 100 according to an embodiment of the present invention.

Referring to FIG. 1 , the low noise amplifier 100 according to an embodiment of the present invention electrically connects an input terminal Vin and an output terminal Vout, and includes a first transistor unit 110 and a second transistor disposed in parallel. Includes section 120.

The first point P1 is a point where the input line connected from the input terminal Vin branches to the first transistor unit 110 and the second transistor unit 120, respectively, and the second point P2 is the first transistor unit. This is the point where the first output line of 110 and the second output line of the second transistor unit 120 join. The second point P2 is connected to the output terminal Vout through an output line.

The first transistor unit 110 is interposed between the input terminal Vin and the output terminal Vout, and electrically connects the input terminal Vin and the output terminal Vout. That is, the first transistor unit 110 is connected to the first point P1 and the second point P2, receives and amplifies the input signal from the input terminal Vin, and outputs the amplified first output signal to the output terminal Vout. ) can be sent.

The first transistor unit 110 may include a first transistor 111 and a first transmission line 113 interposed between the first transistor 111 and the output terminal Vout.

Here, the first transistor 111 may include a base terminal B1, an emitter terminal E1, and a collector terminal C1. The base terminal B1 of the first transistor 111 is electrically connected to the first point P1 to receive an input signal from the input terminal Vin. An emitter terminal E1 of the first transistor 111 may be grounded, and a collector terminal C1 may be electrically connected to one end of the first transmission line 113 . The other end of the first transmission line 113 is electrically connected to the second point P2. Accordingly, the input signal input to the first transistor 111 is amplified and output to the output terminal Vout through the first transmission line 113 .

Here, the first transmission line 113 may include a material or structure having an inductance component in a high frequency band.

The second transistor unit 120 is interposed between the input terminal Vin and the output terminal Vout and disposed in parallel with the first transistor unit 110 . That is, the second transistor unit 120 is connected to the first point P1 and the second point P2, receives and amplifies the input signal from the input terminal Vin, and outputs the amplified second output signal to the output terminal Vout. ) can be sent.

The second transistor unit 120 may include a second transistor 121 and a second transmission line 123 interposed between the input terminal Vin and the second transistor 121 .

Similarly, the second transistor 121 may include a base terminal B2, an emitter terminal E2, and a collector terminal C2. The base terminal B2 of the second transistor 121 may be electrically connected to one end of the second transmission line 123 . The other end of the second transmission line 123 may be connected to the first point P1. Accordingly, the base terminal B2 of the second transistor 121 may receive an input signal passing through the second transmission line 123 from the input terminal Vin. The emitter terminal E2 of the second transistor 121 is grounded, and the collector terminal C2 is a second terminal connected to the output terminal Vout by joining the first transistor unit 110 and the second transistor unit 120. It may be connected to the point P2. Accordingly, the input signal passing through the second transmission line 123 is amplified while passing through the second transistor 121, and the amplified second output signal can be transmitted to the output terminal Vout through the second point P2. .

The second transmission line 123 may include a material or structure having an inductance component in a high frequency band.

When the first output signal output from the first transistor unit 110 and the second output signal output from the second transistor unit 120 join at the second point P2, the first transmission line 113 connects the first transmission line 113 to the first transmission line 113. A phase difference between the output signal and the second output signal may be minimized. Therefore, in one embodiment, the length of the first transmission line 113 can be adjusted so that the phase difference between the first output signal and the second output signal can be minimized. In another embodiment, the width of the first transmission line 113 may be adjusted to minimize a phase difference between the first output signal and the second output signal. In another embodiment, the length and width of the first transmission line 113 may be adjusted to minimize a phase difference between the first output signal and the second output signal.

The second transmission line 123 adjusts the magnitude of the second output signal so that the first output signal output from the first transistor unit 110 and the second output signal output from the second transistor unit 120 have a preset signal ratio. can be adjusted Here, the preset signal ratio may be determined according to a ratio between noise characteristics of the first transistor 111 and noise characteristics of the second transistor 121 . As an example, the length of the second transmission line 123 may be adjusted so that the first output signal and the second output signal have a preset signal ratio. In another embodiment, the width of the second transmission line 123 may be adjusted so that the first output signal and the second output signal have a preset signal ratio. In another embodiment, the length and width of the second transmission line may be adjusted so that the first output signal and the second output signal have a preset signal ratio.

As an example, the first transistor 111 and the second transistor 121 may be N-type Metal-Oxide Semiconductor (NMOS) transistors. The NMOS transistor may be formed using a CMOS process or formed through a compound process, but is not limited thereto.

In one embodiment, the first transistor 111 and the second transistor 121 may be formed on the same substrate through the same process. Here, being formed through the same process means that some of the formation processes such as doping, deposition, and etching for forming at least some components of the first transistor 111 and the second transistor 121 are overlapped or performed simultaneously. can be

In one embodiment, noise characteristics of the first transistor 111 may be lower than noise characteristics of the second transistor 121 . Here, the noise is generated due to heat and other sources, and may be generated when high output power of the transmitter flows into the receiver in the long-distance communication system in the ultra-high frequency band. In the second transistor unit 120, the second transmission line 123 is disposed between the first point P1 connected to the input terminal Vin and the second transistor 121, so that the second transmission line 123 is input. Noise characteristics of the second transistor 121 may be attenuated due to signal loss. Therefore, in order to keep the noise characteristics of the first transistor unit 110 and the second transistor unit 120 similar, the noise characteristics of the first transistor 111 may be lower than those of the second transistor 121. have.

In one embodiment, in order for the second transistor 121 to have higher noise characteristics, the width of the first transistor 111 may be wider than that of the second transistor 121 . The width ratio of the first transistor 111 and the second transistor 121 may be determined in consideration of an input signal loss in the second transmission line 123 .

In one embodiment, the width of the second transistor 121 may be 60% to 90% of the width of the first transistor 111, and in another embodiment, the width of the second transistor 121 is the first transistor 75% of the width of (111). As an example, the width of the first transistor 111 may be 20±1 μm, and the width of the second transistor 121 may be 15±1 μm.

2 is a diagram illustrating a low noise amplifier 200 including a plurality of transistors, according to one embodiment of the present invention.

Referring to FIG. 2, the low noise amplifier 200 according to an embodiment of the present invention includes a first transistor electrically connected to the input terminal Vin and the output terminal Vout, and interposed between the first transistor and the output terminal Vout. A second transistor including N first transistor units 210a, b, c?? including the first transmission line and electrically connected to the input terminal Vin and the output terminal Vout; M second transistor units 220a, b ?? including second transmission lines interposed between transistors may be included. In this case, M and N are natural numbers of 1 or more, and may be the same number or different numbers.

The first transistor unit 210 and the second transistor unit 220 may be disposed in parallel to electrically connect the input terminal Vin and the output terminal Vout. The first transistor unit 210 and the second transistor unit 220 may be alternately disposed, but are not limited thereto, and are disposed differently according to electrical characteristics of the first transistor, the first transmission line, the second transistor, and the second transmission line. It can be.

3 is a graph showing a relationship between a transistor width and noise characteristics of a conventional low noise amplifier, and FIG. 4 is a graph showing a relationship between a transistor width and maximum input power of a conventional low noise amplifier.

Referring to FIG. 3 , when a high-frequency signal of 80 GHz is input to a low-noise amplifier including one transistor according to the prior art, the relationship between transistor width and noise characteristics can be confirmed. When the transistor width changes from 15 μm to 50 μm, it can be seen that the noise characteristic value of the low noise amplifier changes linearly from about 1.72 dB to 2.32 dB. Therefore, it can be confirmed that the smaller the width of the transistor, the lower the noise characteristic value, and the better the noise characteristic.

Referring to FIG. 4, in a low noise amplifier including one transistor according to the prior art, when the width of the transistor is formed differently, it is possible to check the change in the gain of the transistor according to the change in input power (dBm). . The widths of the transistors constituting the low-noise amplifier were formed to be 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, and 45 μm, respectively. It can be seen that as the width of the transistor decreases, the value of the maximum input power (P1dB), which rapidly decreases the gain of the transistor, also decreases.

Therefore, the noise characteristics of the transistor and the value of the maximum input power are in a trade-off relationship, so when simply increasing the width of the transistor to improve the value of the maximum input power, one of the important characteristics of the low noise amplifier Performance degradation of the in-noise characteristics cannot be avoided.

5 is a diagram illustrating a minimum noise characteristic value and an input/output matching impedance value of a low noise amplifier according to an embodiment of the present invention.

Referring to FIG. 5, in the low noise amplifier according to an embodiment of the present invention, noise characteristic values when the first transistor has a width of 20 μm and the second transistor has a width of 15 μm can be confirmed through simulation. have. Since the second transmission line of the second transistor is located between the input terminal and the base terminal, and noise characteristics are attenuated, the width of the second transistor is smaller than that of the first transistor in order to keep the noise characteristics of the first transistor and the second transistor similar. narrowly formed. When the input impedance of the low noise amplifier is (19.872 + j * 13.809) and the output impedance is (20.016 + j * 28.417), the noise characteristic of the low noise amplifier may have a minimum value of 1.895 dB.

6a to 6c are gain graphs of low noise amplifiers having different transistor widths according to the prior art.

6A to 6C are graphs of simulation results of gain values of conventional low noise amplifiers including transistors having widths of 15 μm (Comparative Example 1), 20 μm (Comparative Example 2), and 35 μm (Comparative Example 3), respectively. is indicated by At this time, the input/output impedance of each transistor was set to minimize the noise characteristic value.

Referring to FIG. 6A , in the case of the low noise amplifier according to Comparative Example 1, the maximum input power (P1dB) may be 2.600 dB and the minimum noise characteristic may be 1.725 dB.

Referring to FIG. 6B , in the case of the low noise amplifier according to Comparative Example 2, the maximum input power (P1dB) may be 3.800 dB and the minimum noise characteristic may be 1.847 dB.

Referring to FIG. 6C , in the case of the low noise amplifier according to Comparative Example 3, the maximum input power (P1dB) may be 6.6 dB and the minimum noise characteristic may be 2.138 dB.

As described above, as the width of the transistor increases, the maximum input power (P1dB) increases, but the minimum noise characteristic value also increases, confirming that the noise characteristic is attenuated.

7 is a gain graph of a low noise amplifier according to an embodiment of the present invention.

In the low noise amplifier according to an embodiment of the present invention, the first transistor has a width of 20 μm and the second transistor has a width of 15 μm. Referring to FIG. 7 , it can be seen that the maximum input power (P1dB) of the low noise amplifier according to an embodiment of the present invention is 6.600 dB, the same as that of the low noise amplifier according to Comparative Example 3 shown in FIG. 6C. On the other hand, it can be seen that the minimum noise characteristic value is 1.895 dB, which is significantly reduced compared to 2.138 dB of Comparative Example 3.

As described above, the low noise amplifier according to an embodiment of the present invention can maintain a low minimum noise characteristic value while improving maximum input power. Therefore, the low noise amplifier according to an embodiment of the present invention can be used as a low noise amplifier for a long distance communication system in an ultra-high frequency band.

On the other hand, those skilled in the art related to the present embodiment will be able to understand that it can be implemented in a modified form within a range that does not deviate from the essential characteristics of the above description. Therefore, the disclosed methods are to be considered in an illustrative rather than a limiting sense. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the equivalent scope will be construed as being included in the present invention.

As described above, although the embodiments have been described with limited examples and drawings, those skilled in the art can make various modifications and variations from the above description. For example, the described techniques may be performed in an order different from the method described, and/or components of the described system, structure, device, circuit, etc. may be combined or combined in a different form than the method described, or other components may be used. Or even if it is replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents of the claims are within the scope of the following claims.

100: low noise amplifier
110: first transistor unit
111: first transistor
113: first transmission line
120: second transistor unit
121: second transistor
123: second transmission line
200: low noise amplifier
210: first transistor unit
220: second transistor unit

Claims (14)

a first transistor unit including a first transistor electrically connected to an input terminal and an output terminal, and a first transmission line interposed between the first transistor and the output terminal; and
A second transistor unit including a second transistor electrically connected to the input terminal and the output terminal, and a second transmission line interposed between the input terminal and the second transistor;
The first transistor unit and the second transistor unit are connected in parallel, the low noise amplifier. According to claim 1,
Wherein the first transistor and the second transistor are NMOS transistors. According to claim 1,
The noise figure of the first transistor is lower than that of the second transistor, the low noise amplifier. According to claim 1,
The width of the first transistor is wider than the width of the second transistor, the low noise amplifier. According to claim 4,
The width of the second transistor is 60% to 90% of the width of the first transistor, the low noise amplifier. According to claim 4,
The width of the first transistor is 20 ± 1 μm, the width of the second transistor is 15 ± 1 μm, the low noise amplifier. According to claim 1,
The first transmission line has an inductance component in a high frequency band and minimizes a phase difference between a first output signal output from the first transistor unit and a second output signal output from the second transistor unit. According to claim 7,
The first transmission line is a low noise amplifier, the length of which is determined to minimize the phase difference between the first output signal and the second output signal. According to claim 7,
Wherein the first transmission line has a width determined to minimize a phase difference between the first output signal and the second output signal. According to claim 1,
The second transmission line has an inductance component in a high frequency band,
The second transmission line adjusts the magnitude of the second output signal so that the first output signal output from the first transistor unit and the second output signal output from the second transistor unit have a preset signal ratio. amplifier. According to claim 10,
The preset signal ratio is determined according to a ratio between noise characteristics of the first transistor and noise characteristics of the second transistor. According to claim 10,
The second transmission line is of a length determined so that the first output signal and the second output signal have the preset signal ratio. According to claim 10,
wherein the second transmission line has a width determined such that the first output signal and the second output signal have the preset signal ratio. a plurality of first transistor units including a first transistor electrically connected to an input terminal and an output terminal, and a first transmission line interposed between the first transistor and the output terminal; and
A plurality of second transistor units including a second transistor electrically connected to the input terminal and the output terminal, and a second transmission line interposed between the input terminal and the second transistor;
The first transistor parts and the second transistor parts are connected in parallel, the low noise amplifier.

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