CN115864000A - Kilo-frequency-range monopole low-frequency small-power low-noise high-sensitivity active antenna - Google Patents

Abstract

The invention discloses a kilo-octave monopole low-frequency small-electric low-noise high-sensitivity active antenna which comprises an electric small monopole whip antenna and an active amplifier, wherein the electric small monopole whip antenna is used for receiving an external electromagnetic wave signal and taking a voltage signal sensed after receiving an external electromagnetic wave signal as a radio frequency input signal of the active amplifier; the active amplifier comprises a high-resistance input amplifier, a front-stage voltage follower, a broadband amplifier, a rear-stage voltage follower and an impedance matcher which are sequentially connected, and besides high gain, the active amplifier also has the function of realizing kilo-octave and impedance conversion from high resistance to 50 ohms. The invention has the advantages of small size of the antenna, low working frequency, thousands of frequency ranges of frequency band, low noise coefficient, high sensitivity, low power consumption and the like.

Description

A thousand-octave monopole low-frequency electrically small, low-noise, high-sensitivity active antenna

technical field

The invention relates to the technical field of antennas, in particular to a thousand-octave monopole low-frequency electrically small, low-noise, and high-sensitivity active antenna.

Background technique

（/>

为电磁波波长）时，即为电小天线。当天线长度远小于电磁波波长时，天线的效率或增益将随着天线长度缩短而变小，其感应的接收信号将变得非常微弱，如果不采取适当的措施，该天线甚至无法正常接收信号。对此，一般采用增加放大器方案解决此问题。但当天线工作频率低至10kHz（千赫兹）、频率范围达千个倍频程、天线细长比为170，以及天线长度只有/>

（/>

表示低频波长）时，由于该天线在低频段，其输入阻抗实部很小，而虚部呈容性且容抗很大，为了接收微弱信号，现有放大技术因为放大器输入端口的输入阻抗有限，对于电小天线高阻输入无法满足阻抗匹配、超宽频带、低噪声系数和高灵敏度的要求。According to the basic theory of antenna design, for low-frequency antennas, the form of wire antennas is usually used, and its length is generally a half-wave oscillator. According to the antenna definition, when the maximum size of the antenna is less than 0.159

(/>

When it is the electromagnetic wave wavelength), it is an electrically small antenna. When the length of the antenna is much smaller than the wavelength of the electromagnetic wave, the efficiency or gain of the antenna will become smaller as the length of the antenna is shortened, and the received signal induced by it will become very weak. If proper measures are not taken, the antenna will not even be able to receive the signal normally. In this regard, the general solution to this problem is to increase the amplifier. However, when the operating frequency of the antenna is as low as 10kHz (kilohertz), the frequency range reaches a thousand octaves, the antenna slenderness ratio is 170, and the antenna length is only />

(/>

Indicates low-frequency wavelength), because the antenna is in the low-frequency band, the real part of its input impedance is very small, while the imaginary part is capacitive and the capacitive reactance is very large. In order to receive weak signals, the existing amplification technology has limited input impedance due to the input port of the amplifier. , the high-impedance input of an electrically small antenna cannot meet the requirements of impedance matching, ultra-wideband, low noise figure and high sensitivity.

Contents of the invention

The present invention aims to solve one of the technical problems in the related art at least to a certain extent. Therefore, an object of the present invention is to provide a thousand-octave monopole low-frequency electrically small, low-noise, and high-sensitivity active antenna.

In order to achieve the above object, the present invention is achieved through the following technical solutions:

A thousand-octave monopole low-frequency electrically small, low-noise, high-sensitivity active antenna, comprising:

Electric small monopole whip antenna, the equivalent impedance of the electric small monopole whip antenna is a high-impedance impedance, and the electric small monopole whip antenna is used to receive external electromagnetic wave signals, and the voltage induced after receiving the external electromagnetic wave signals The signal is used as the RF input signal of the active amplifier;

The active amplifier, the active amplifier includes:

A high-impedance input amplifier, the high-impedance input amplifier is connected to the electric small monopole whip antenna, the high-impedance input amplifier is used to amplify the radio frequency input signal, and the high gain of the high-impedance input amplifier facilitates reducing the noise figure of the active amplifier, wherein the input impedance of the high-impedance input amplifier is greater than the equivalent impedance of the electrically small monopole whip antenna, so as to effectively obtain radio frequency input signal power to improve sensitivity;

A pre-stage voltage follower is connected to the high-impedance input amplifier, and the pre-stage voltage follower is used to reduce the output impedance of the high-impedance input amplifier, so that the reduced output impedance is consistent with the input of the broadband amplifier of the rear stage Impedance matching;

The broadband amplifier is connected to the previous-stage voltage follower, and the broadband amplifier is used to increase the signal bandwidth to realize a thousand-octave frequency band, and to amplify the signal output by the previous-stage voltage follower;

A subsequent stage voltage follower and an impedance matcher, the latter stage voltage follower is connected to the broadband amplifier, the impedance matcher is connected to the latter stage voltage follower, and the latter stage voltage follower is used to reduce the The output impedance of the broadband amplifier, and impedance matching is performed on the output impedance of the broadband amplifier through the impedance matching device, so as to convert the output impedance of the active amplifier into a 50 ohm impedance output.

Optionally, the electrically small monopole whip antenna is equivalent to a circuit formed by series connection of a low-frequency equivalent voltage source, an equivalent resistance, and an equivalent capacitance, and the radio frequency input signal of the active amplifier is The voltage signal of the low-frequency equivalent voltage source, the voltage signal is induced by the electric small monopole whip antenna by receiving the external electromagnetic wave signal.

Optionally, the active amplifier is equivalent to the load of the electrically small monopole whip antenna when applied.

Optionally, the high-impedance input amplifier includes a first triode and a field effect transistor, and the first triode and the field effect transistor are connected in a cascode manner of a Wahlmann circuit structure, to increase the input impedance of the high-impedance input amplifier.

Optionally, the cascode method is specifically that the emitter of the first transistor is connected to the drain of the field effect transistor, and the source of the field effect transistor is connected to the first triode The base connection of the transistor.

Optionally, the first transistor is a low-noise broadband NPN type blue-scale silicon epitaxial planar transistor, and the field effect transistor is an N-channel junction field effect transistor with low noise and large transconductance, wherein the field effect transistor The effect transistor adopts a large transconductance N-channel junction field effect transistor, which is convenient for reducing the output impedance of the high-impedance input amplifier.

Optionally, the broadband amplifier includes a common emitter circuit in which two stages of gain amplifiers are cascaded.

Optionally, the common emitter circuit specifically includes:

A second diode and a third diode, the collector of the second diode is connected to the base of the third diode, the emitter of the second diode is connected to the third diode The emitter of the diode is connected, and the high-gain design of the broadband amplifier is realized through the common-emitter circuit, wherein the second diode and the third diode are low-noise broadband amplifiers that facilitate gain improvement NPN type green-shift silicon epitaxial planar triode.

Optionally, a feedback unit is connected between the emitter of the second diode and the collector of the third diode, and the bandwidth of the broadband amplifier is increased through the feedback unit to realize a thousand-octave band.

Optionally, the feedback unit is designed based on a series connection of a resistor and a capacitor.

The present invention has at least the following technical effects:

1. The high-impedance input amplifier of the present invention adopts a large N-channel junction field-effect transistor with high-impedance, low-noise and transconductance, and a low-noise broadband NPN type blue-grade silicon with input reactance similar to the output reactance of an electrically small monopole whip antenna. Epitaxial planar triodes, connected in series cascode based on Wahlmann circuit structure, can effectively reduce the equivalent capacitance of the imaginary part of the impedance of the high-impedance input amplifier, eliminate the additional equivalent capacitance introduced by the Miller effect, and increase the Input impedance value, so that the input impedance of the high-impedance input amplifier matches the equivalent impedance of the electrically small monopole whip antenna, thereby making the active amplifier of the present invention suitable for the higher electrically small monopole whip antenna of impedance, and because The input impedance of the high-impedance input amplifier is relatively large, and is much greater than the equivalent impedance of the electric small monopole whip antenna, and then the signal power received by the electric small monopole whip antenna can be obtained more effectively, which is conducive to improving the sensitivity of the active antenna of the present invention In addition, the high-impedance input amplifier of the present invention can also have high gain by adopting the above-mentioned structural design, thereby reducing the impact of subsequent link noise on the equivalent input noise of the entire link, thereby facilitating further improvement of the active antenna of the present invention. sensitivity.

2. The present invention adopts a two-stage cascaded common-emitter broadband amplifier, and adds a feedback unit between the stages, which can improve the voltage gain of the entire link while facilitating the broadband amplifier to have a higher input impedance to match the previous stage voltage. The follower output impedance is matched, and it is easy to obtain thousand octave bands.

3. The active antenna of the present invention has the advantages of small antenna size, low frequency, wide frequency band, high sensitivity, low noise figure, moderate compensation gain, low power consumption and strong anti-interference ability.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

FIG. 1 is a working principle diagram of a thousand-octave monopole low-frequency electrically small, low-noise, high-sensitivity active antenna according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a partial circuit structure of a high-impedance input amplifier according to an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a common emitter circuit according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a sensitivity test of an active amplifier according to an embodiment of the present invention.

Detailed ways

The present embodiment will be described in detail below, examples of which are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

A thousand-octave monopole low-frequency electrically small, low-noise, and high-sensitivity active antenna of this embodiment will be described below with reference to the accompanying drawings.

FIG. 1 is a working principle diagram of a thousand-octave monopole low-frequency electrically small, low-noise, high-sensitivity active antenna according to an embodiment of the present invention. As shown in Figure 1, the active antenna includes an electrically small monopole whip antenna and an active amplifier, which includes: a high-impedance input amplifier, a pre-stage voltage follower, a broadband amplifier, a post-stage voltage follower, and impedance matching The high-impedance input amplifier is connected to the electric small monopole whip antenna at the front stage, and the rear stage of the high-impedance input amplifier is connected to the front-stage voltage follower, broadband amplifier, rear-stage voltage follower and impedance matcher in sequence. Of course, the active antenna also includes a DC stabilized power supply for powering the active amplifier.

The electrically small monopole whip antenna in this embodiment is used to receive external electromagnetic wave signals, and the voltage signal induced after receiving the external electromagnetic wave signals is used as the radio frequency input signal of the active amplifier. The active amplifier can amplify the voltage signal induced by the active antenna, that is, the radio frequency input signal, improve the signal gain, improve the sensitivity of the active antenna, and can reduce the noise figure of the entire signal chain, and can realize a thousand-octave frequency range, and has The function of impedance transformation and impedance matching from input high impedance transformation to 50 ohm impedance.

Specifically, as shown in Figure 1, the electric small monopole whip antenna is equivalent to a circuit formed by series connection of a low-frequency equivalent voltage source, an equivalent resistance and an equivalent capacitance, wherein the radio frequency input signal of the active amplifier It is a voltage signal of a low-frequency equivalent voltage source, which is induced by an electric small monopole whip antenna by receiving an external electromagnetic wave signal.

的电小单极鞭天线，当入射电磁波沿天线方向的电场分量为/>

时，天线的感应电压/>

，其中，/>

为天线的有效高度，/>

。For example, for the actual length of the antenna is

The electrically small monopole whip antenna, when the electric field component of the incident electromagnetic wave along the direction of the antenna is />

, the induced voltage of the antenna />

, where />

is the effective height of the antenna, />

.

It should be noted that the equivalent impedance of the electrically small monopole whip antenna in this embodiment is a high-impedance impedance. According to the antenna principle, for an electrically small monopole whip antenna with an effective height of 0.6 meters, a height much smaller than the defined value of the electrically small size, and a slenderness ratio of 170, the equivalent resistance of the electrically small monopole whip antenna is very small, equivalent to The capacitive reactance of the capacitor is very large, especially in the low frequency band, the equivalent impedance of the electric small monopole whip antenna is a high impedance impedance, so the existing amplification technology cannot meet the requirements of impedance matching, ultra-wide frequency band, low noise figure and high sensitivity . In the active antenna proposed by the present invention, the active amplifier can meet this requirement through the above-mentioned link design of high-impedance input amplifier, pre-stage voltage follower, broadband amplifier, post-stage voltage follower and impedance matcher.

Further, the active amplifier in this embodiment and its subsequent receiver can be equivalent to the load of the electrically small monopole whip antenna when applied. The high-impedance input amplifier in this embodiment can be used to amplify the radio frequency input signal input by the electric small monopole whip antenna, wherein, the high gain of the high-impedance input amplifier can facilitate the reduction of the noise figure of the active amplifier, and the high-impedance input amplifier By designing the input impedance greater than the equivalent impedance of the electric small monopole whip antenna, it is convenient to effectively obtain the power of the radio frequency input signal to improve the sensitivity.

FIG. 2 is a schematic diagram of a partial circuit structure of a high-impedance input amplifier according to an embodiment of the present invention. As shown in Figure 2, the high-impedance input amplifier in this embodiment may include a first triode and a field effect transistor, and the first triode and the field effect transistor adopt a series cascode method of a Wahlmann circuit structure connected to increase the input impedance of the high-impedance input amplifier.

Wherein, the cascode mode is specifically that the emitter of the first triode is connected to the drain of the field effect transistor, and the source of the field effect transistor is connected to the base of the first triode.

It should be noted that the first triode is a low-noise broadband NPN type blue-scale silicon epitaxial planar triode, wherein the NPN type triode is a triode composed of two N-type semiconductors interspersed with a P-type semiconductor, and NPN is specifically a triode type. The field effect transistor of this embodiment is an N-channel junction field effect transistor with low noise and large transconductance, wherein the field effect transistor adopts a large transconductance N-channel junction field effect transistor, which is convenient for reducing the output impedance of the high-impedance input amplifier .

In this embodiment, since the performance of the Wahlmann structure amplifier and the common source amplifier are the same, the Wahlmann structure combines the advantages of the common drain circuit and the common source circuit, and it is used as an active amplifier in this embodiment The design basis can effectively reduce the equivalent capacitance of the imaginary part of the impedance of the high-impedance input amplifier, and eliminate the additional equivalent capacitance introduced by the Miller effect, so that the equivalent input capacitance of the high-impedance input amplifier is equivalent to the equivalent input capacitance of the common drain structure , so as to increase the input impedance value. When the input impedance is greater than 10 megohms, it can be matched with the impedance of the previous electric small monopole whip antenna, so as to obtain the signal power received by the electric small monopole whip antenna as much as possible, and improve the active Antenna sensitivity.

In addition, in this embodiment, a Wahlmann structure is adopted, and a series cascode high-impedance input is designed based on a low-noise broadband NPN type blue-scale silicon epitaxial planar triode and a low-noise large transconductance N-channel junction field effect transistor. Amplifier, which can ensure that the amplification factor meets the preset requirements, that is, the high-impedance input amplifier not only has high input impedance, but also has a certain high gain, which can reduce the impact of the subsequent link noise on the equivalent input noise of the entire link. Influence, so that it is convenient to further improve the sensitivity of the active antenna. In addition, in the high-impedance input amplifier in this embodiment, while ensuring that the amplification factor meets the preset requirements, an N-channel junction field effect transistor with a relatively large transconductance can be selected to obtain a single-stage N-channel junction field effect transistor. The approximate input impedance of the common-drain amplifier circuit can reduce the output impedance when the electric small monopole whip antenna matches the high-impedance input amplifier, and play the role of impedance transformation.

The front-stage voltage follower in this embodiment is connected with the high-impedance input amplifier, which is used to reduce the output impedance of the high-impedance input amplifier, so that the output impedance after the reduction matches the input impedance of the broadband amplifier of the subsequent stage, thereby facilitating the subsequent The stage amplifier circuit works normally.

It should be noted that the core device of the circuit design of the front-stage voltage follower in this embodiment is a low-noise broadband NPN type green-scale silicon epitaxial planar triode.

The broadband amplifier in this embodiment is connected with the previous stage voltage follower, and the broadband amplifier is used to increase the signal bandwidth to realize the thousand-octave frequency range, and amplifies the signal output by the previous stage voltage follower. Wherein, the broadband amplifier includes a common emitter circuit in which two stages of gain amplifiers are cascaded.

FIG. 3 is a schematic structural diagram of a common emitter circuit according to an embodiment of the present invention. As shown in FIG. 3 , the common emitter circuit specifically includes a second diode and a third diode, both of which are low-noise broadband NPN type green-shift silicon epitaxial planar triodes that facilitate gain improvement. Wherein, the collector of the second diode is connected to the base of the third diode through the first capacitor, the emitter of the second diode is connected to the emitter of the third diode, and the broadband amplifier is connected to the base of the third diode through the common The emitter circuit enables high-gain designs.

Further, a feedback unit is also connected between the emitter of the second diode and the collector of the third diode, and the feedback unit includes a series resistance and a second capacitor, and the broadband amplifier can be controlled by the feedback unit. Increase bandwidth to achieve kilo-octave frequency bands.

The broadband amplifier in this embodiment is composed of a common-emitter circuit in which two gain amplifiers are cascaded, and a feedback unit is added between the stages to further increase the bandwidth to provide the gain required by the preset design. It should be noted that the core component of broadband amplifier design in this embodiment is a low-noise broadband NPN type green-scale silicon epitaxial planar triode with an amplification factor of more than 100, which can gain 20dB (decibels) in the entire frequency range.

It can be understood that this embodiment adopts two cascaded common-emitter broadband amplifiers, and a feedback unit is added between the stages, which can increase the voltage gain of the entire link and facilitate the broadband amplifier to have a higher input impedance, so as to It matches the output impedance of the pre-stage voltage follower, and it is convenient to obtain a thousand-octave frequency.

The rear-stage voltage follower in this embodiment is connected with the broadband amplifier, and the impedance matcher is connected with the subsequent-stage voltage follower. The latter-stage voltage follower is used to reduce the output impedance of the broadband amplifier, and the output impedance of the broadband amplifier is adjusted by the impedance matcher. Perform impedance matching to accurately transform the approximately 50-ohm output impedance of the subsequent voltage follower into a 50-ohm impedance output, thereby adapting to the characteristic impedance of the signal line, reducing signal transmission loss, and obtaining maximum signal power.

Specifically, the circuit structure of the rear-stage voltage follower is the same as that of the previous-stage voltage follower, the difference is that the output impedance of the subsequent-stage voltage follower is as low as approximately 50 ohms, and the latter-stage voltage follower is used to further reduce the output impedance , the core device of its circuit design is a low-noise broadband NPN type green-scale silicon epitaxial planar triode. The impedance matching device in this embodiment is at the rear end of the voltage follower in the subsequent stage, and it converts the output impedance of the output port to 50 ohms accurately by connecting a resistor with a certain resistance in series.

It should be noted that the input impedance of the active amplifier in this embodiment is designed based on the measured data of the electric small monopole whip antenna. According to the frequency domain characteristics of the input impedance, the active amplifier can be integrated and optimized with the entire circuit.

Among them, the sensitivity test can be performed on the active amplifier. FIG. 4 is a schematic diagram of a sensitivity test of an active amplifier according to an embodiment of the present invention. As shown in Figure 4, the equivalent model of the electric small monopole whip antenna can be simulated by using the radio frequency signal generator, namely the signal source, the equivalent capacitance and the matching resistance used to match the internal resistance of the signal source, and then connected to this implementation Example of the active amplifier, and then through the measuring instrument for sensitivity testing.

The active antenna of this embodiment has the advantages of small antenna size, low frequency, wide frequency band, high sensitivity, low noise figure, moderate compensation gain, low power consumption and strong anti-interference ability through the above design.

，远小于一般电小尺寸定义的长度/>

（/>

表示低频波长，/>

为圆周率），然后频率可低至10kHz，频率范围能够达到千个倍频程，输出阻抗可从天线高阻变换成50欧姆输出，另外灵敏度较高，如在100 kHz以上灵敏度为10，100kHz以下灵敏度为40，并且本实施例的有源天线还具有噪声系数低的特点，如在整个工作频率范围内噪声系数不大于6~8dB，且补偿增益适中，其可增益20dB，而且平稳；以及本实施例的有源天线还具有功耗低的特点，其功耗小于0.7瓦，而且电路设计元器件国产化程度高，其电路设计元器件均采用国产元器件，安全性高，并且本实施例的有源天线的整个放大器电路没有逻辑电路和存储器等元器件，因此抗电磁脉冲干扰能力强。Specifically, the effective antenna height of the active antenna of this embodiment is only

, much smaller than the length defined by the general electrical small size />

(/>

Indicates the low-frequency wavelength, />

pi), then the frequency can be as low as 10kHz, the frequency range can reach a thousand octaves, the output impedance can be transformed from antenna high impedance to 50 ohm output, and the sensitivity is higher, such as the sensitivity above 100 kHz is 10, below 100kHz The sensitivity is 40, and the active antenna of this embodiment also has the characteristics of low noise figure, such as the noise figure is not greater than 6~8dB in the whole operating frequency range, and the compensation gain is moderate, and it can gain 20dB, and it is stable; and this The active antenna of the embodiment also has the characteristics of low power consumption, its power consumption is less than 0.7 watts, and the degree of localization of circuit design components is high, and its circuit design components are all domestic components, which has high safety, and this embodiment The entire amplifier circuit of the active antenna has no components such as logic circuits and memories, so it has a strong ability to resist electromagnetic pulse interference.

In summary, the present invention not only can realize the amplification of the weak signal received by the antenna by designing an active amplifier with thousand-octave frequency, low frequency, low noise and high sensitivity, and combining it with a passive electric small monopole whip antenna , It can also realize impedance transformation and matching, so that the signal output can also have the technical characteristics of thousand octave frequency, ultra-wide frequency band, low noise figure and high sensitivity on the basis of obtaining a certain gain compensation.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or order between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. Various modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the above disclosure. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (10)

1. A thousand-octave single-pole low-frequency electrically small, low-noise, high-sensitivity active antenna, characterized in that it comprises: Electric small monopole whip antenna, the equivalent impedance of the electric small monopole whip antenna is a high-impedance impedance, and the electric small monopole whip antenna is used to receive external electromagnetic wave signals, and the voltage induced after receiving the external electromagnetic wave signals The signal is used as the RF input signal of the active amplifier; The active amplifier, the active amplifier includes: A high-impedance input amplifier, the high-impedance input amplifier is connected to the electric small monopole whip antenna, the high-impedance input amplifier is used to amplify the radio frequency input signal, and the high gain of the high-impedance input amplifier facilitates reducing the noise figure of the active amplifier, wherein the input impedance of the high-impedance input amplifier is greater than the equivalent impedance of the electrically small monopole whip antenna, so as to effectively obtain radio frequency input signal power to improve sensitivity; A pre-stage voltage follower is connected to the high-impedance input amplifier, and the pre-stage voltage follower is used to reduce the output impedance of the high-impedance input amplifier, so that the reduced output impedance is consistent with the input of the broadband amplifier of the rear stage Impedance matching; The broadband amplifier is connected to the previous-stage voltage follower, and the broadband amplifier is used to increase the signal bandwidth to realize a thousand-octave frequency band, and to amplify the signal output by the previous-stage voltage follower; A subsequent stage voltage follower and an impedance matcher, the latter stage voltage follower is connected to the broadband amplifier, the impedance matcher is connected to the latter stage voltage follower, and the latter stage voltage follower is used to reduce the The output impedance of the broadband amplifier, and impedance matching is performed on the output impedance of the broadband amplifier through the impedance matching device, so as to convert the output impedance of the active amplifier into a 50 ohm impedance output. 2. The thousand-octave monopole low-frequency electric small low-noise high-sensitivity active antenna as claimed in claim 1, is characterized in that, described electric small monopole whip antenna and a low-frequency equivalent voltage source, an equivalent resistance A circuit formed in series with an equivalent capacitor is equivalent, the radio frequency input signal of the active amplifier is the voltage signal of the low-frequency equivalent voltage source, and the voltage signal is passed by the electric small monopole whip antenna It is obtained by receiving the external electromagnetic wave signal and inducing. 3. The thousand-octave monopole low-frequency electrically small low-noise high-sensitivity active antenna as claimed in claim 1, is characterized in that, the active amplifier is equivalent to the electric small monopole whip antenna when applied load. 4. The thousand-octave monopole low-frequency electrically small, low-noise, high-sensitivity active antenna as claimed in claim 1, wherein said high-impedance input amplifier comprises a first triode and a field effect transistor, and said first A triode and the field effect transistor are connected in a series cascode manner of a Wahlmann circuit structure, so as to increase the input impedance of the high-impedance input amplifier. 5. The thousand-octave monopole low-frequency electrically small, low-noise, high-sensitivity active antenna as claimed in claim 4, wherein said string cascode mode is specifically the emission of said first triode The pole is connected to the drain of the field effect transistor, and the source of the field effect transistor is connected to the base of the first triode. 6. The thousand-octave monopole low-frequency electric small low-noise high-sensitivity active antenna as claimed in claim 5, is characterized in that, the first triode is a low-noise broadband NPN type blue file silicon epitaxial planar triode, The field effect transistor is an N-channel junction field effect transistor with low noise and large transconductance, wherein the field effect transistor adopts a large transconductance N-channel junction field effect transistor, which is convenient to reduce the output impedance. 7. The thousand-octave monopole low-frequency electrically small, low-noise, and high-sensitivity active antenna according to claim 1, wherein the broadband amplifier comprises a common-emitter circuit in which two stages of gain amplifiers are cascaded. 8. The thousand-octave monopole low-frequency electrically small, low-noise, high-sensitivity active antenna as claimed in claim 7, wherein the common emitter circuit specifically comprises: A second diode and a third diode, the collector of the second diode is connected to the base of the third diode, the emitter of the second diode is connected to the third diode The emitter of the diode is connected, and the high-gain design of the broadband amplifier is realized through the common-emitter circuit, wherein the second diode and the third diode are low-noise broadband amplifiers that facilitate gain improvement NPN type green-shift silicon epitaxial planar triode. 9. The thousand-octave monopole low-frequency electrically small, low-noise, high-sensitivity active antenna as claimed in claim 8, wherein the emitter of the second diode and the set of the third diode A feedback unit is connected between the electrodes, and the bandwidth of the broadband amplifier is increased through the feedback unit to realize a thousand-octave frequency range. 10. The thousand-octave monopole low-frequency electrically small, low-noise, and high-sensitivity active antenna according to claim 9, wherein the feedback unit is designed based on a series connection of a resistor and a capacitor.

Images