Low noise amplifier circuit

Abstract

The invention relates to the technical field of microelectronics, semiconductors and communication, and discloses a low-noise amplifier circuit which comprises a resistor R1, a resistor R2, a resistor Rn, a capacitor C1, a capacitor C2, a capacitor Cn, a transistor M1, a transistor M2, a transistor Mn, two microstrip lines Ld, four microstrip lines Ld / 2, two microstrip lines Lg, a resistor Zd and a resistor Zg. The low-noise amplifier circuit provided by the invention has the characteristics of low noise coefficient and broadened frequency band, and the low-noise amplifier circuit has gain for increasing flatness in a band and has relatively low noise at high frequency in the band, so that the overall performance of the low-noise amplifier circuit is improved.

Description

Technical Field

[0001] The present invention relates to the fields of microelectronics, semiconductors and communication technology, and in particular to a low noise amplifier circuit. Background Art

[0002] In the receiving module of the wireless communication system, the first active device that receives the signal from the antenna is the low noise amplifier (LNA). On the one hand, the low noise amplifier can amplify the weak signal received by the antenna from the external environment to demodulate the required data information for the system; on the other hand, it can reduce the noise interference of the system and improve the sensitivity of the whole machine. Nowadays, people have higher and higher requirements for various wireless communication tools, such as low power radiation, long working distance, wide coverage, etc., which puts higher requirements on the receiving sensitivity of the system.

[0003] In some applications of RF communication circuits, for example, the first-stage RF amplifier circuit of the receiver in a long-distance wireless communication system, since the RF signal is already very weak after long-distance transmission, the noise of the amplifier circuit must be reduced as much as possible to improve the signal-to-noise ratio. At this time, the main goal of designing the amplifier circuit is to reduce noise and obtain the minimum noise factor. In the design of RF amplifier circuits, obtaining maximum power gain and minimum noise factor are contradictory. Therefore, it is necessary to obtain the minimum noise factor at the expense of power gain. Generally, in the design of RF circuits, it is necessary to take into account both noise and gain, and select a compromise solution to meet the design requirements. In RF communication circuits, with the increase in communication distance and the widespread application of wireless communication systems, many receiving systems need to process very weak RF signals, so the noise factor is the most important indicator of low noise amplifiers. Summary of the invention

[0004] Based on this, it is necessary to address the technical problem of poor performance of the low noise amplifier in the prior art, and propose a low noise amplifier circuit, the low noise amplifier circuit comprising: a resistor R1, a resistor R2, a resistor Rn, a capacitor C1, a capacitor C2, a capacitor Cn, a transistor M1, a transistor M2, a transistor Mn, two microstrip lines Ld, four microstrip lines Ld / 2, two microstrip lines Lg, a resistor Zd, and a resistor Zg;

[0005] One end of the resistor R1 and one end of the capacitor C1 are connected to the gate of the transistor M1, and the source of the transistor M1 is grounded; one end of the resistor R2 and one end of the capacitor C2 are connected to the gate of the transistor M2, and the source of the transistor M2 is grounded; one end of the resistor Rn and one end of the capacitor Cn are connected to the gate of the transistor Mn, and the source of the transistor Mn is grounded;

[0006] One end of the resistor Zd is grounded, the other end of the resistor Zd is connected to one end of the first microstrip line Ld / 2, the other end of the first microstrip line Ld / 2 is connected to one end of the first microstrip line Ld, the other end of the first microstrip line Ld is connected to one end of the second microstrip line Ld, the other end of the second microstrip line Ld is connected to one end of the second microstrip line Ld / 2, and the other end of the second microstrip line Ld / 2 is a radio frequency signal output end;

[0007] One end of the third microstrip line Ld / 2 is a radio frequency signal input end, the other end of the third microstrip line Ld / 2 is connected to one end of the first microstrip line Lg, the other end of the first microstrip line Lg is connected to one end of the second microstrip line Lg, the other end of the second microstrip line Lg is connected to one end of the fourth microstrip line Ld / 2, the other end of the fourth microstrip line Ld / 2 is connected to one end of the resistor Zg, and the other end of the resistor Zg is grounded;

[0008] The other end of the resistor R1 and the other end of the capacitor C1 are connected to the other end of the third microstrip line Ld / 2, and the drain of the transistor M1 is connected to the other end of the first microstrip line Ld / 2;

[0009] The other end of the resistor R2 and the other end of the capacitor C2 are connected to the other end of the first microstrip line Lg, and the drain of the transistor M2 is connected to the other end of the first microstrip line Ld;

[0010] The other end of the resistor Rn and the other end of the capacitor Cn are connected to the other end of the second microstrip line Lg, and the drain of the transistor Mn is connected to the other end of the second microstrip line Ld.

[0011] The low-noise amplifier circuit proposed in the present invention comprises a resistor R1, a resistor R2, a resistor Rn, a capacitor C1, a capacitor C2, a capacitor Cn, a transistor M1, a transistor M2, a transistor Mn, two microstrip lines Ld, four microstrip lines Ld / 2, two microstrip lines Lg, a resistor Zd, and a resistor Zg. The low-noise amplifier circuit proposed in the present invention has the characteristics of low noise coefficient and widened frequency band, and the low-noise amplifier circuit has an increased flat gain within the band and has lower noise at high frequencies within the band, thereby improving the overall performance of the low-noise amplifier circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] in:

[0014] Figure 1 is a schematic diagram of the circuit structure of a low noise amplifier circuit in one embodiment;

[0015] Figure 2 is a gain curve of a low noise amplifier circuit according to a frequency variation in one embodiment;

[0016] Figure 3 : is the noise figure of the low noise amplifier circuit according to one embodiment as it varies with frequency. DETAILED DESCRIPTION

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0018] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1 As shown, Figure 1 A circuit structure diagram of a low noise amplifier circuit provided by an embodiment of the present invention, the low noise amplifier circuit comprises: the low noise amplifier circuit comprises: a resistor R1, a resistor R2, a resistor Rn, a capacitor C1, a capacitor C2, a capacitor Cn, a transistor M1, a transistor M2, a transistor Mn, two microstrip lines Ld, four microstrip lines Ld / 2, two microstrip lines Lg, a resistor Zd, and a resistor Zg;

[0021] One end of the resistor R1 and one end of the capacitor C1 are connected to the gate of the transistor M1, and the source of the transistor M1 is grounded; one end of the resistor R2 and one end of the capacitor C2 are connected to the gate of the transistor M2, and the source of the transistor M2 is grounded; one end of the resistor Rn and one end of the capacitor Cn are connected to the gate of the transistor Mn, and the source of the transistor Mn is grounded;

[0022] One end of the resistor Zd is grounded, the other end of the resistor Zd is connected to one end of the first microstrip line Ld / 2, the other end of the first microstrip line Ld / 2 is connected to one end of the first microstrip line Ld, the other end of the first microstrip line Ld is connected to one end of the second microstrip line Ld, the other end of the second microstrip line Ld is connected to one end of the second microstrip line Ld / 2, and the other end of the second microstrip line Ld / 2 is a radio frequency signal output end;

[0023] One end of the third microstrip line Ld / 2 is a radio frequency signal input end, the other end of the third microstrip line Ld / 2 is connected to one end of the first microstrip line Lg, the other end of the first microstrip line Lg is connected to one end of the second microstrip line Lg, the other end of the second microstrip line Lg is connected to the fourth microstrip line Ld / 2, the other end of the fourth microstrip line Ld / 2 is connected to one end of the resistor Zg, and the other end of the resistor Zg is grounded;

[0024] The other end of the resistor R1 and the other end of the capacitor C1 are connected to the other end of the third microstrip line Ld / 2, and the drain of the transistor M1 is connected to the other end of the first microstrip line Ld / 2;

[0025] The other end of the resistor R2 and the other end of the capacitor C2 are connected to the other end of the first microstrip line Lg, and the drain of the transistor M2 is connected to the other end of the first microstrip line Ld;

[0026] The other end of the resistor Rn and the other end of the capacitor Cn are connected to the other end of the second microstrip line Lg, and the drain of the transistor Mn is connected to the other end of the second microstrip line Ld.

[0027] The value of n is determined by the number of transistors M.

[0028] It should be noted that the low noise amplifier circuit proposed in the present invention includes a circuit composed of multiple groups of similar resistors Rn and capacitors Cn connected in parallel to the gate of the transistor Mn, and has the characteristics of low noise coefficient and widened frequency band.

[0029] refer to Figure 2 As shown, Figure 2 It is a gain curve that changes with frequency. The results in this figure show that the low-noise amplifier circuit proposed by the present invention can make the amplifier have an increased flat gain within the band, and adjusting the value of RC can solve the problem that the amplifier gain drops sharply as the frequency increases.

[0030] refer to Figure 3 As shown, Figure 3 It is the noise coefficient that changes with frequency. The result in this figure shows that the low-noise amplifier circuit proposed by the present invention can make the amplifier have lower noise at high frequencies within the band, and the value of RC can significantly improve the size of the noise.

[0031] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A low noise amplifier circuit, characterized in that: The low noise amplifier circuit comprises: a resistor R1, a resistor R2, a resistor Rn, a capacitor C1, a capacitor C2, a capacitor Cn, a transistor M1, a transistor M2, a transistor Mn, two microstrip lines Ld, four microstrip lines Ld / 2, two microstrip lines Lg, a resistor Zd, and a resistor Zg; One end of the resistor R1 and one end of the capacitor C1 are connected to the gate of the transistor M1, and the source of the transistor M1 is grounded; one end of the resistor R2 and one end of the capacitor C2 are connected to the gate of the transistor M2, and the source of the transistor M2 is grounded; one end of the resistor Rn and one end of the capacitor Cn are connected to the gate of the transistor Mn, and the source of the transistor Mn is grounded; One end of the resistor Zd is grounded, the other end of the resistor Zd is connected to one end of the first microstrip line Ld / 2, the other end of the first microstrip line Ld / 2 is connected to one end of the first microstrip line Ld, the other end of the first microstrip line Ld is connected to one end of the second microstrip line Ld, the other end of the second microstrip line Ld is connected to one end of the second microstrip line Ld / 2, and the other end of the second microstrip line Ld / 2 is a radio frequency signal output end; One end of the third microstrip line Ld / 2 is a radio frequency signal input end, the other end of the third microstrip line Ld / 2 is connected to one end of the first microstrip line Lg, the other end of the first microstrip line Lg is connected to one end of the second microstrip line Lg, the other end of the second microstrip line Lg is connected to one end of the fourth microstrip line Ld / 2, the other end of the fourth microstrip line Ld / 2 is connected to one end of the resistor Zg, and the other end of the resistor Zg is grounded; The other end of the resistor R1 and the other end of the capacitor C1 are connected to the other end of the third microstrip line Ld / 2, and the drain of the transistor M1 is connected to the other end of the first microstrip line Ld / 2; The other end of the resistor R2 and the other end of the capacitor C2 are connected to the other end of the first microstrip line Lg, and the drain of the transistor M2 is connected to the other end of the first microstrip line Ld; The other end of the resistor Rn and the other end of the capacitor Cn are connected to the other end of the second microstrip line Lg, and the drain of the transistor Mn is connected to the other end of the second microstrip line Ld.

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