阅读说明：本技术 一种确定有源单极天线功率增益的方法 (Method for determining power gain of active monopole antenna ) 是由 马银圣 金珠 于 2021-08-11 设计创作，主要内容包括：本发明公开了一种确定有源单极天线功率增益的方法,包括如下步骤：步骤1：假定有源网络的输入端口为1端口,输出端口为2端口,利用网络分析仪测量有源网络二端口散射参数的四个分量；步骤2：求得无源振子端输入反射系数和负载端输入反射系数；步骤3：仿真计算无源振子的电性能,得到有源单极天线无源振子的方向系数和效率；步骤4：计算有源单极天线的功率增益。本发明所公开确定有源单极天线功率增益的方法,将实测数据和计算数据相结合,原理简单,无需采用特殊仪器设备,可操作性强,准确度高。(The invention discloses a method for determining power gain of an active monopole antenna, which comprises the following steps: step 1: assuming that an input port of an active network is a port 1 and an output port is a port 2, measuring four components of scattering parameters of two ports of the active network by using a network analyzer; step 2: obtaining an input reflection coefficient of a passive oscillator end and an input reflection coefficient of a load end; and step 3: simulating and calculating the electrical property of the passive oscillator to obtain the direction coefficient and efficiency of the passive oscillator of the active monopole antenna; and 4, step 4: the power gain of the active monopole antenna is calculated. The method for determining the power gain of the active monopole antenna combines the measured data and the calculated data, has simple principle, does not need special instruments and equipment, and has strong operability and high accuracy.)

1. A method of determining power gain of an active monopole antenna, comprising the steps of:

step 1: assuming that an input port of an active network is 1 port and an output port is 2 ports, a network analyzer is utilized to measure four components S of S scattering parameters of two ports of the active network₁₁、S₁₂、S₂₁And S₂₂；

Step 2: measuring the input impedance of the passive oscillator and the load by using a network analyzer, respectively marked as Z_gAnd Z_LBy usingCalculating the input reflection coefficient gamma of the passive vibrator end_gAnd load side input reflection coefficient gamma_LAnd combining the definition of the S parameter to obtain the efficiency K of the active network as follows:

and step 3: simulating and calculating the electrical property of the passive oscillator to obtain the direction coefficient D and the efficiency eta of the passive oscillator of the active monopole antenna;

and 4, step 4: power gain G of active monopole antenna_aIs determined by the following formula:

substituting the components obtained in the step 1, the step 2 and the step 3 to calculate the power gain G of the active monopole antenna_a；

When the load terminals are perfectly matched, i.e. F_LPower gain G of active monopole antenna-0_aSimplifying into:

Technical Field

The invention belongs to the field of wireless communication, and particularly relates to a method for determining power gain of an active monopole antenna in the field.

Background

The active monopole antenna is a common antenna form of a short wave receiving antenna, and combines a passive oscillator (such as a monopole antenna of a whip antenna and the like) with an active network, wherein the active network plays roles of protection, matching and amplification, the passive oscillator becomes an input part of the active network, the active network can be regarded as a loading network of the passive oscillator, the bandwidth and the gain disadvantage of the passive oscillator antenna are compensated through the amplification effect of the active network, the impedance characteristic of the passive oscillator is improved, the working frequency band is widened, the signal-to-noise ratio of the active monopole antenna and the whole receiving system is improved, higher gain is obtained, and the miniaturization of the antenna is realized. As shown in the schematic block diagram of the active monopole antenna in fig. 1, the signal flow of the active monopole antenna is obtained by sensing a radio frequency signal by a passive oscillator, and the radio frequency signal is transmitted to a receiver through a feeder after passing through an active network having composite functions of protection, input matching, amplification, output matching, and the like.

Because the matching mode adopted by the common short wave active monopole antenna is not power matching, noise matching and voltage matching, the impedance mismatching of the active network and the passive oscillator is serious, the power gain of the active monopole antenna is obtained by adopting simulation calculation in the conventional method, or S scattering parameters of the active network are directly tested by adopting a network analyzer, and then the obtained | S is utilized₂₁|²The gain of the parasitic element is multiplied to be used as the power gain of the active monopole antenna. The former method is completely through simulation calculation, but some devices contained in an active network are difficult to accurately model, such as a transmission line impedance converter and the like, so that errors are large, and the latter method combines measured data, but because the input end of the active network is seriously mismatched with a test port of a network analyzer, the conventional method is incomplete in processing, and large errors are brought to subsequent short-wave communication link design and project demonstration. It is apparent that there is a need to devise a method for accurately determining the power gain of an active monopole antenna to provide guidance and reference for index assignment and project demonstration of short wave communication links.

Disclosure of Invention

The invention aims to provide a method for determining the power gain of an active monopole antenna.

The invention adopts the following technical scheme:

in a method of determining power gain of an active monopole antenna, the improvement comprising the steps of:

step 1: assuming that an input port of an active network is 1 port and an output port is 2 ports, a network analyzer is utilized to measure four components S of S scattering parameters of two ports of the active network₁₁、S₁₂、S₂₁And S₂₂；

Step 2: measuring the input impedance of the passive oscillator and the load by using a network analyzer, respectively marked as Z_gAnd Z_LBy usingCalculating the input reflection coefficient gamma of the passive vibrator end_gAnd load side input reflection coefficient gamma_LAnd combining the definition of the S parameter to obtain the efficiency K of the active network as follows:

and step 3: simulating and calculating the electrical property of the passive oscillator to obtain the direction coefficient D and the efficiency eta of the passive oscillator of the active monopole antenna;

and 4, step 4: power gain G of active monopole antenna_aIs determined by the following formula:

substituting the components obtained in the step 1, the step 2 and the step 3 to calculate the power gain G of the active monopole antenna_a；

When the load terminals are perfectly matched, i.e. F_LPower gain G of active monopole antenna-0_aSimplifying into:

the invention has the beneficial effects that:

the invention discloses a method for determining the power gain of an active monopole antenna, which combines the working principle of a short-wave active monopole antenna, fully considers the impedance mismatch condition of each port, and performs data calculation by using the actually measured impedance data of the active monopole antenna and the S scattering parameter of an active network to obtain the power gain of the active monopole antenna. The method combines the measured data and the calculated data, has simple principle, does not need special instruments and equipment, has strong operability and high accuracy, and can provide guidance and reference for index distribution and project demonstration of the short-wave communication link by the power gain of the active monopole antenna deduced and calculated, so that the technical indexes of the active network and each part of the passive oscillator are reasonably distributed according to the gain requirement of the short-wave communication link on the active monopole antenna, and further, corresponding parameter design is pertinently carried out, and the resource waste caused by overlarge design margin is avoided. The development period of the project can be shortened, and the application capability of the project can be obviously enhanced.

Drawings

FIG. 1 is a functional block diagram of an active monopole antenna;

fig. 2 is a schematic diagram of signal transmission before and after an active network.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As known from antenna theory, an important parameter characterizing antenna performance is power gain. It is a relative value that is compared to an ideal point source antenna. It is defined as: under the condition of the same input power, the ratio of the power density obtained by a certain receiving point of the researched antenna in the maximum radiation direction to the power density obtained by the ideal point source antenna at the same receiving point. According to the antenna principle knowledge, the power gain G of a passive element is equal to the product of the directional coefficient D and the efficiency η, i.e., G ═ D η.

For the active monopole antenna, the antenna consists of a passive oscillator and an active network, besides the gain of the passive oscillator,the efficiency of the active network should also be included. In this case, the power gain of the active monopole antenna can be represented by formula G_aKD η denotes, where K is the efficiency of the active network. It has no direct relation to the directivity, efficiency of the parasitic element, but each affects the overall gain in a different way. Because the direction coefficient D and the efficiency eta of the passive oscillator are generally obtained by calculation, when the efficiency K of the active network can be accurately tested, the power gain of the active monopole antenna can be determined.

From the perspective of the receiving antenna, the equivalent of the passive oscillator is voltage E and internal resistance Z_gVoltage source of, Z_gIs a complex impedance that varies with frequency. When the passive oscillator and the load (namely the receiver) are inserted into an active network with the functions of protection, input matching, amplification and output matching, the power gain of the active monopole antenna is determined for determining the efficiency of the active network, and various matching problems of the passive oscillator, the active network, the load and a test system are also involved.

In embodiment 1, this embodiment discloses a method for determining a power gain of an active monopole antenna, which derives and calculates the power gain of the active monopole antenna based on two port S scattering parameters of an actual measurement active network, an input impedance of a passive element, an input impedance of a load, and a direction coefficient and efficiency of the passive element calculated through simulation.

As shown in FIG. 2, assume that the input port of the active network is 1 port and the output port is 2 ports, a₁、b₁Incident and emergent amplitudes, a, of 1 port respectively₂、b₂Incident and emergent amplitudes of 2 ports, respectively, b_gRepresenting the amplitude of the signal that the parasitic element can provide to the reflection-free active network. Also assume Γ₁Is the input reflection coefficient, Γ, of the port of the active network 1_g、Γ_LInput reflection coefficients, S, of the passive oscillator side and the load side, respectively₁₁、S₁₂、S₂₁And S₂₂Representing four components of the scattering parameter at the two ports S of the active network. Then does not have power oscillationResource power P of son_AComprises the following steps:net power P absorbed by load₂Comprises the following steps: p₂＝|b₂|²-|a₂|²＝|b₂|²(1-|Γ_L|²)。

The method specifically comprises the following steps:

step 1: measuring four components S of scattering parameter of two-port S of active network by using network analyzer₁₁、S₁₂、S₂₁And S₂₂；

Step 2: measuring the input impedance of the passive oscillator and the load by using a network analyzer, respectively marked as Z_gAnd Z_LBy usingCalculating the input reflection coefficient gamma of the passive vibrator end_gAnd load side input reflection coefficient gamma_LAnd combining the definition of the S parameter to obtain the efficiency K of the active network as follows:

and step 3: simulating and calculating the electrical property of the passive oscillator to obtain the direction coefficient D and the efficiency eta of the passive oscillator of the active monopole antenna;

and 4, step 4: power gain G of active monopole antenna_aIs determined by the following formula:

based on the power gain formula of the active monopole antenna, substituting the actually measured S scattering parameter components of the two ports of the active network and the input reflection coefficient gamma of the passive oscillator end_gLoad end input reflection coefficient gamma_LAnd calculating the passive oscillator direction coefficient D and the efficiency eta by simulation calculation to obtain the power gain G of the active monopole antenna_a。

When the load terminals are perfectly matched, i.e. F_LIs equal to 0 and hasPower gain G of source monopole antenna_aSimplifying into:

only the component S of the scattering parameter of the two ports S of the active network is measured at this time₁₁、S₂₁Input reflection coefficient gamma of passive oscillator terminal_gAnd the passive oscillator direction coefficient D and the efficiency eta which are subjected to simulation calculation, the power gain G of the active monopole antenna can be obtained through calculation_a。

Based on the steps, the power gain of the active monopole antenna can be accurately calculated by combining the actually measured input impedance, the S scattering parameter of the active network, the calculated passive oscillator direction coefficient D and the efficiency eta, the method fully considers the influence caused by impedance mismatch of each port, has strong operability and high accuracy, and the derived and calculated power gain of the active monopole antenna can provide guidance and reference for index distribution and project demonstration of a short-wave communication link, shortens the development period of a project and has strong practicability.