CN108574466B

CN108574466B - Radio frequency low noise amplifier

Info

Publication number: CN108574466B
Application number: CN201810813725.0A
Authority: CN
Inventors: 张华硕
Original assignee: Shanghai Awinic Technology Co Ltd
Current assignee: Shanghai Awinic Technology Co Ltd
Priority date: 2018-07-23
Filing date: 2018-07-23
Publication date: 2023-10-20
Anticipated expiration: 2038-07-23
Also published as: CN108574466A

Abstract

The invention provides a radio frequency low noise amplifier, which comprises a transistor, wherein the transistor comprises a substrate, a grid electrode wiring, a grid electrode, a source electrode, a drain electrode and an isolation layer which are positioned on the substrate; the grid is electrically connected with the radio frequency signal input end through a grid wiring; the isolation layer is positioned between the substrate and the grid wiring, and the isolation layer is electrically connected with the source electrode. The isolation layer is positioned between the substrate and the grid electrode wiring, so that the isolation layer can isolate noise of the substrate and prevent the grid electrode wiring from introducing the noise of the substrate into the grid electrode; in addition, because the isolation layer is electrically connected with the source electrode, parasitic capacitance between the isolation layer and the gate wiring does not affect the input impedance matching and the gain of the radio frequency low noise amplifier.

Description

Radio frequency low noise amplifier

Technical Field

The invention relates to the technical field of low-noise amplifiers, in particular to a radio frequency low-noise amplifier.

Background

The radio frequency low noise amplifier is an amplifier with very low noise coefficient. Are commonly used as high-frequency or intermediate-frequency preamplifiers for various radio receivers, and as amplification circuits for high-sensitivity electronic detection devices. Where weak signals are amplified, the noise of the amplifier itself may be very disturbing to the signal, and it is therefore desirable to reduce this noise to improve the signal to noise ratio of the output. A conventional rf low noise amplifier is shown IN fig. 1 and includes a field effect transistor including a substrate, a gate G on the substrate, a source S and a drain D, the gate G being connected to a signal input IN through a gate trace. Since the gate wiring is directly above the substrate and the parasitic resistance R of the substrate _B Noise is generated, and thus parasitic capacitance C between the gate wiring and the substrate _GB The noise of the substrate is introduced into the gate G, which results in a larger noise figure of the rf low noise amplifier, affecting the performance of the rf low noise amplifier.

Disclosure of Invention

In view of the above, the present invention provides a low noise amplifier for solving the problem that the parasitic capacitance between the gate trace and the substrate in the existing low noise amplifier introduces the noise of the substrate into the gate, resulting in a larger noise factor of the low noise amplifier.

In order to achieve the above purpose, the present invention provides the following technical solutions:

a radio frequency low noise amplifier comprising a transistor comprising a substrate, a gate trace on the substrate, a gate, a source, a drain and an isolation layer;

the grid is electrically connected with the radio frequency signal input end through the grid wiring;

the isolation layer is located between the substrate and the gate wiring, and the isolation layer is electrically connected with the source electrode.

Preferably, the isolation layer is made of metal.

Compared with the prior art, the technical scheme provided by the invention has the following advantages:

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a conventional RF LNA;

fig. 2 is a schematic top view of a rf low noise amplifier according to an embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of the RF LNA shown in FIG. 2 along the cutting line AA';

fig. 4 is a schematic cross-sectional view of the rf low noise amplifier shown in fig. 3.

Detailed Description

As described in the background art, in the existing rf low noise amplifier, the parasitic capacitance between the gate trace and the substrate may introduce the noise of the substrate into the gate, resulting in a larger noise figure of the rf low noise amplifier. The inventor researches that an isolation layer is arranged between the grid wire and the substrate, and the isolation layer is connected with the ground, so that substrate noise can be prevented from being introduced into the grid, but new parasitic capacitance is introduced into the mode, namely the capacitance between the grid wire and the isolation layer, and the input impedance matching of the radio frequency low noise amplifier is influenced by the new parasitic capacitance.

Accordingly, the present invention has been made to overcome the above-mentioned problems occurring in the prior art, and an rf low noise amplifier includes a transistor including a substrate, a gate wire on the substrate, a gate electrode, a source electrode, a drain electrode, and an isolation layer;

According to the radio frequency low-noise amplifier provided by the invention, the isolation layer is positioned between the substrate and the grid electrode wiring, so that the isolation layer can isolate the noise of the substrate and prevent the grid electrode wiring from introducing the noise of the substrate into the grid electrode; in addition, because the isolation layer is electrically connected with the source electrode, parasitic capacitance between the isolation layer and the gate wiring does not affect the input impedance matching and the gain of the radio frequency low noise amplifier.

The foregoing is a core idea of the present invention, and in order that the above-mentioned objects, features and advantages of the present invention can be more clearly understood, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

An embodiment of the present invention provides a radio frequency low noise amplifier, which includes a transistor, as shown in fig. 2 and 3, including a substrate 10, a gate wire 11 on the substrate 10, a gate G, a source S, a drain D, and an isolation layer 12.

The gate G is electrically connected to the radio frequency signal input terminal IN through the gate wire 11, and after a signal input by the radio frequency signal input terminal IN is transmitted to the gate G through the gate wire 11, the transistor can be controlled to be turned on or turned off; the isolation layer 12 is located between the substrate 10 and the gate wire 11, and the isolation layer 12 is electrically connected with the source S.

Note that the spacer 12 is electrically connected to only the source electrode S, that is, the spacer 12 is not electrically connected to the gate electrode G nor to the ground. Further, the material of the gate wire 11 is metal, and the material of the isolation layer 12 is also metal, however, the invention is not limited thereto, and in other embodiments, the material of the isolation layer 12 may be other conductive materials.

Further, as shown in FIG. 4, the source S and the inductor L _S Connection, inductance L _S Is grounded at the other end of the inductor L _S Mainly used for realizing impedance matching. The drain electrode D is connected with the signal output end and is used for outputting the amplified signal.

In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A radio frequency low noise amplifier comprising a transistor, the transistor comprising a substrate, a gate trace on the substrate, a gate, a source, a drain, and an isolation layer;

2. The amplifier of claim 1, wherein the spacer is metallic.