CN103646126A - Design method of micro-strip array focusing antenna and micro-strip array focusing antenna - Google Patents

Abstract

Aiming at the defects of unsatisfactory focusing effect or a large number of side lobes in the existing focusing antenna design method, the present invention proposes a new design method of microstrip array focusing antenna and the designed microstrip array focusing antenna, the antenna unit The coupling effect has been taken into account, and the obtained phase distribution can just meet the quadratic spherical wave distribution required by the design of the focusing antenna, and at the same time, the transmission efficiency can be maximized. The designed focusing antenna has almost no side lobes and has the best amplitude and phase distribution, effective focusing distance and transmission efficiency have all been significantly improved.

Description

Design Method of Microstrip Array Focusing Antenna and Microstrip Array Focusing Antenna

technical field

The invention belongs to the technical field of planar antenna design, and in particular relates to a novel design method of a focusing antenna with higher precision and a microstrip array focusing antenna designed by the method. the

Background technique

Microwaves have long been known as a means of information transmission and have developed rapidly in recent years. Microwave as a means of power transmission was first proposed in the 19th century, and preliminary experimental research was carried out. The advantage of microwave as a means of power transmission is that it realizes wireless power transmission, which has practical value in many occasions. Since the 1950s, people have begun to study the problem of electromagnetic energy transmission, and electromagnetic waves have been used as a means of energy transmission. This wireless energy transmission method has developed rapidly since the 1970s. For example, the California Institute of Technology's jet The laboratory demonstrated the ground microwave power transmission system working in the S-band, and the helicopter powered by microwave. In the late 1980s, the focus of energy transmission shifted to space activities, and the working frequency also shifted from S-band to Ka-band and F-band. The main application of microwave energy transmission in space is to transmit solar energy collected by satellites or space working platforms to satellites or the ground. This is a costly project, but the economic benefits it brings are also very considerable. the

In order to ensure that the electromagnetic wave energy does not spread during space transmission, the electromagnetic wave must be able to focus to the receiving device like light. From the analogy of light focusing, we know that in order to focus the electromagnetic wave, the phase of the aperture of the transmitting antenna must be spherically distributed. In the early 1960s, Goubao, Shermen, Borigiotti and others did a lot of work on the focusing of aperture antennas, and established the theoretical basis for electromagnetic wave energy transmission. The theory of electromagnetic wave focusing can be used not only for microwave energy transmission, but also for radar and microwave directed energy weapons. For microwave directed energy weapons, its function is to maximize the current distribution of the target in the interested part; for radar, its function is to increase the echo intensity. At the same time, microwave-induced high temperature, which can be applied in medicine, should focus the energy on cancerous tissue for high-temperature heating without posing a threat to the surrounding healthy tissue. the

The traditional focus antenna is by placing a dielectric lens in front of the horn antenna. This type of focus antenna has high side lobes near the focus plane. Obviously, the result of this type of focus antenna is not very ideal, and this type of focus antenna is usually small in size It is very large, and the design is very difficult, and it is not easy to realize. At the same time, the cost is very high, and it cannot meet the wide application of engineering. the

M. Bogosanovic gave a design method with equal amplitude and different phases, that is, the phase satisfies the quadratic spherical wave distribution, while the amplitude remains unchanged. From the experimental results, there are a large number of side lobes near the focusing position, and the focusing effect is not good. Very ideal. the

Shaya Karimkashi gave a method of designing a focusing antenna based on the Dolf-Chershev distribution, that is, different amplitudes and different phases, where the amplitude satisfies the Chershev distribution, and the phase satisfies the quadratic spherical wave distribution. From the experiment As a result, this design method reduces the sidelobe to below -20dB, and the obtained near-field distribution map is also very good, but there is an obvious shortcoming, that is, the difference between the actual position of the focus point and the simulated focus position The error is relatively large. The theoretical focus position is 200mm, but the actual focus distance is only 60mm. Obviously, this design method is still not ideal. Therefore, it is very necessary and of great practical significance to study a new design scheme of microstrip array focusing antenna. the

Contents of the invention

Aiming at the defects of unsatisfactory focusing effect and a large number of side lobes in the existing focusing antenna design method, the present invention proposes a novel microstrip array focusing antenna design method and a microstrip array focusing antenna, and the designed focusing antenna has almost no side lobes with optimal amplitude-phase distribution. the

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

A design method for a microstrip array focusing antenna, comprising the steps of:

Step 1. Form an array of antenna units as the transmitting antenna, place an antenna with the same size as the transmitting antenna unit at the expected focus position as the receiving antenna, and construct a wireless transmission system;

Step 2. Define the scattering parameter matrix of the wireless transmission system as follows:

$\left[\begin{array}{c}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span>\\ <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span>\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; tt</span>}}<span\; class="notranslate">\; ]</span>& <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; tr</span>}}<span\; class="notranslate">\; ]</span>\\ <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; rt</span>}}<span\; class="notranslate">\; ]</span>& <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; rr</span>}}<span\; class="notranslate">\; ]</span>\end{array}\right]\left[\begin{array}{c}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span>\\ <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span>\end{array}\right]$

Where [a _t ]=[a ₁ ,a ₂ ,...,a _n ] ^T , [a _r ]=[a _n+1 ], [b _t ]=[b ₁ ,b ₂ ,..., b _n ] ^T , [b _r ]=[b _n+1 ], the subscript 't' indicates the transmitting antenna, 'r' indicates the receiving antenna, a _i (i=1,2…n+1) indicates the normalization Incident wave, b _i (i=1,2,…n+1) represents the normalized reflected wave, S _tt , S _rt , S _tr , S _rr represent the corresponding S parameters;

Step 3. Define the transmission efficiency T _array as the ratio of the power of the receiving antenna to the input power of the transmitting antenna:

${\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; array</span>}}<span\; class="notranslate">\; =</span>\frac{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ;</span>$

Step 4. Calculate the excitation amplitude and phase of each transmitting unit by the following formula:

[A][a _t ]=T _array [B][a _t ]

[a_t]为发射天线阵各单元端口的激励；  in

[a _t ] is the excitation of each unit port of the transmitting antenna array;

Step 5. Obtain the relevant scattering parameters of the antenna array through the electromagnetic field simulation software, and design the feeding network after the excitation of each port calculated according to the formula in step 4, so that the assigned value of each port is consistent with the calculated value. the

As a preferred solution of the design method of the microstrip array focusing antenna, the array includes a planar array structure or a line array structure. the

As a preferred solution of the design method of the microstrip array focusing antenna, the electromagnetic field simulation software includes IE3D, HFSS or FEKO electromagnetic simulation software. the

A microstrip array focusing antenna is composed of antenna units distributed in an array and a feeding network connecting the antenna units, and the feeding network is designed through the following steps:

Step 1. Place an antenna with the same size as the transmitting antenna unit at the expected focus position of the transmitting antenna as the receiving antenna, and the receiving antenna and the transmitting antenna form a wireless transmission system;

Step 2. Define the scattering parameter matrix of the wireless transmission system as follows:

$\left[\begin{array}{c}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span>\\ <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span>\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; tt</span>}}<span\; class="notranslate">\; ]</span>& <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; tr</span>}}<span\; class="notranslate">\; ]</span>\\ <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; rt</span>}}<span\; class="notranslate">\; ]</span>& <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; rr</span>}}<span\; class="notranslate">\; ]</span>\end{array}\right]\left[\begin{array}{c}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span>\\ <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span>\end{array}\right]$

Where [a _t ]=[a ₁ ,a ₂ ,...,a _n ] ^T , [a _r ]=[a _n+1 ], [b _t ]=[b ₁ ,b ₂ ,..., b _n ] ^T , [b _r ]=[b _n+1 ], the subscript 't' indicates the transmitting antenna, 'r' indicates the receiving antenna, a _i (i=1,2…n+1) indicates the normalization Incident wave, b _i (i=1,2,…n+1) represents the normalized reflected wave, S _tt , S _rt , S _tr , S _rr represent the corresponding S parameters;

Step 3. Define the transmission efficiency T _array as the ratio of the power of the receiving antenna to the input power of the transmitting antenna:

${\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; array</span>}}<span\; class="notranslate">\; =</span>\frac{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ;</span>$

Step 4. Calculate the excitation amplitude and phase of each transmitting unit by the following formula:

[A][a _t ]=T _array [B][a _t ]

[a_t]为发射天线阵各单元端口的激励；  in

[a _t ] is the excitation of each unit port of the transmitting antenna array;

Step 5. Obtain the relevant scattering parameters of the antenna array through the electromagnetic field simulation software, and design the feeding network after the excitation of each port calculated according to the formula in step 4, so that the assigned value of each port is consistent with the calculated value. the

As a preferred solution of the microstrip array focusing antenna, the feeding mode of the feeding network includes a coaxial feeding mode or a side feeding mode. the

As a preferred solution of the microstrip array focusing antenna, the array includes a planar array structure or a line array structure. the

Compared with the prior art, the new focusing antenna design method provided by the present invention and the focusing antenna designed according to the method have taken the coupling effect of the antenna unit into consideration, and the obtained phase distribution can just meet the requirements of designing the focusing antenna. The required quadratic spherical wave distribution can maximize the transmission efficiency at the same time, the effective focusing distance and transmission efficiency are significantly improved, and there are almost no side lobes. the

Description of drawings

Figure 1 is a schematic structural diagram of a wireless transmission system formed by a transmitting antenna array and a receiving antenna;

Fig. 2 is a schematic diagram of wireless transmission system signal transmission;

Fig. 3 is a schematic diagram of a single antenna unit;

Figure 4 is a schematic diagram of the feed network, where numbers 1, 2, ..., 17 represent each port;

Fig. 5 is a schematic diagram of transmitting antenna;

Fig. 6 is the electric field normalization figure of antenna array along Z direction;

Fig. 7 is the electric field distribution diagram along the X-axis direction of the antenna at the focal plane;

Fig. 8 is the electric field distribution diagram of the antenna along the Y-axis direction in the focal plane;

Fig. 9 is a distribution diagram of the electric field intensity on the plane where the maximum electric field intensity density is located. the

Detailed ways

The technical solutions provided by the present invention will be described in detail below in conjunction with specific examples. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. the

An important problem in focusing antenna design is to obtain a suitable near-field radiation pattern so that it has lower side lobes, because higher side lobes will affect the accuracy of focusing and transmission efficiency. Therefore, a reasonable amplitude and phase distribution is key to solving this problem. the

Specifically, the present invention adopts the design method of new focusing antenna, comprises the following steps:

Step 1. Based on the wireless power transmission system, in order to maximize the transmission efficiency, the transmission energy of the transmitting antenna is focused on the position of the receiving antenna. First, an array of antenna elements is formed as the transmitting antenna. At the expected focusing position (distance from the transmitting antenna is D ) Place an antenna with the same size as the transmitting antenna unit as the receiving antenna to construct a wireless transmission system. The antenna units in the transmitting antenna are distributed in an array, and the array structure here can adopt various types of array antenna structures, such as area array, line array, conformal array and so on. At this time, the system can be regarded as an n+1 port network as shown in Figure 2, which can be represented by a (n+1)×(n+1) scattering parameter matrix. the

For example, we take the design frequency as 2.45GHZ, the substrate material as FR4, the thickness as 3mm, and 16 antenna elements as an example. The 16 antenna elements are a 4*4 area array structure, the distance between the elements is 60mm, and the expected focusing distance is 100mm, the antenna array and the receiving antenna are placed as shown in Figure 1, the present invention uses the microstrip patch antenna as shown in Figure 3 as the antenna unit, but the microstrip patch antenna should not be used as a limitation of the present invention, it must be pointed out that , antenna units commonly used in the industry can meet the requirements of the present invention. The whole system can be regarded as a 16+1 port network, and the scattering parameter matrix is expressed as:

$\left[\begin{array}{c}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span>\\ <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span>\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; tt</span>}}<span\; class="notranslate">\; ]</span>& <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; tr</span>}}<span\; class="notranslate">\; ]</span>\\ <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; rt</span>}}<span\; class="notranslate">\; ]</span>& <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; rr</span>}}<span\; class="notranslate">\; ]</span>\end{array}\right]\left[\begin{array}{c}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span>\\ <span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span>\end{array}\right]$

Where [a _t ]=[a ₁ ,a ₂ ,...,a _n ] ^T , [a _r ]=[a _n+1 ], [b _t ]=[b ₁ ,b ₂ ,..., b _n ] ^T , [b _r ]=[b _n+1 ], the subscript 't' indicates the transmitting antenna, 'r' indicates the receiving antenna, a _i (i=1,2…n+1) indicates the normalization Incident wave, b _i (i=1,2,…n+1) represents the normalized reflected wave, S _tt , S _rt , S _tr , S _rr represent the corresponding S parameters;

Step 2. Define the transmission efficiency T _array as the ratio of the power of the receiving antenna to the input power of the transmitting antenna:

${\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; array</span>}}<span\; class="notranslate">\; =</span>\frac{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ;</span>$

Step 3. Calculate the excitation amplitude and phase of each transmitting unit by the following formula:

[A][a _t ]=T _array [B][a _t ]

[a_t]为发射天线阵各单元端口的激励；  in

[a _t ] is the excitation of each unit port of the transmitting antenna array;

Step 4. Obtain the relevant scattering parameters of the antenna array through the electromagnetic field simulation software (the electromagnetic field simulation software can use common electromagnetic simulation software such as IE3D or HFSS, FEKO), and then obtain the maximum efficiency value of the corresponding port according to the transmission efficiency between the systems. The optimal distribution value, taking the specific antenna in the present invention as an example, the port excitation obtained by calculation is shown in Table 1:

Table 1

Step 5. According to the obtained port value (the excitation amplitude and phase of the transmitting unit), according to the existing knowledge of the transmission line, make full use of relevant knowledge such as impedance converters and power dividers, based on the fact that the width can change the amplitude and the length can change the phase In principle, design the corresponding feeder network as shown in Figure 4, Figure 5, and Figure 6, so that the assigned value of each port is consistent with the value calculated before. Each of the ports connected to the antenna (2, 3, ..., 17, in Figure 4) is replaced by a 50-ohm input impedance, and 1 in Figure 4 is the feeder. In this example, the feeder adopts coaxial feeder. According to needs, other feeding methods, such as side feeding, can also be used. the

After the feed network is designed, replace the 50-ohm input impedance used in the feed network with the antenna unit, so that the antenna unit and the feed network form a whole. the

Through electromagnetic simulation software and darkroom near-field tests, we obtained the electric field normalization diagram of the antenna array designed by the present invention (Figure 6), the electric field distribution diagram of the antenna along the X-axis direction in the focal plane (Figure 7), and the antenna in the focal plane The electric field distribution diagram along the Y-axis direction (Figure 8), and the electric field intensity distribution diagram of the plane where the maximum electric field intensity density is located (Figure 9). It can be seen from Figure 6 that the test results are in good agreement with the simulation results. Figure 7 shows that there are no side lobes from the main lobe to -35dB, and no side lobes from the main lobe to -25dB in Figure 8. It can be seen from Fig. 9 that the actual focusing distance of the focusing antenna designed by the design method provided by the present invention can reach 80mm, and the effective focusing distance has been significantly improved compared with the prior art. At the same time, there is no side lobe, and the transmission efficiency can reach 30%. . the

The present invention also discloses a microstrip array focusing antenna, which includes a transmitting antenna array, the transmitting antenna array is composed of transmitting units distributed in an array, and the transmitting units are connected through a feeding network, and the feeding network And design through the design method of the microstrip array focusing antenna provided by the present invention. the

The technical means disclosed in the solutions of the present invention are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be pointed out that for those skilled in the art, some improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention. the

Claims (6)

1. a method for designing for microstrip array focusing anteena, is characterized in that, comprises the steps:

Step 1. forms an array as emitting antenna using antenna element, at expection focal position, places an antenna with transmission antenna unit same size as receiving antenna, constructs a wireless transmitting system;

The scattering parameter matrix of the described wireless transmitting system of step 2. definition is as follows:

$\left[\begin{array}{c}\left[b_t\right]\\ \left[b_r\right]\end{array}\right]=\left[\begin{array}{cc}\left[S_{\mathrm{tt}}\right]& \left[S_{\mathrm{tr}}\right]\\ \left[S_{\mathrm{rt}}\right]& \left[S_{\mathrm{rr}}\right]\end{array}\right]\left[\begin{array}{c}\left[a_t\right]\\ \left[a_r\right]\end{array}\right]$

[a wherein _t]=[a ₁, a ₂..., a _n] ^t, [a _r]=[a _n+1], [b _t]=[b ₁, b ₂..., b _n] ^t, [b _r]=[b _n+1], subscript ' t ' represents emitting antenna, ' r ' represents receiving antenna, a _i(i=1,2 ... n+1) represent normalized incident-wave, b _i(i=1,2 ... n+1) represent normalization reflection wave, S _tt, S _rt, S _tr, S _rrrepresent the S parameter that each is corresponding;

Step 3. definition transfer efficiency T _arrayratio for the power of receiving antenna and the power input of emitting antenna:

$T_{\mathrm{array}}=\frac{\frac{1}{2}({\left|\right[b_r\left]\right|}^2-{\left|\right[a_r\left]\right|}^2)}{\frac{1}{2}({\left|\right[a_t\left]\right|}^2-{\left|\right[b_t\left]\right|}^2)};$

The excitation amplitude that step 4. calculates each transmitter unit by following formula is followed phase place:

[A][a _t]=T _array[B][a _t]

Wherein

[a _t] be the excitation of each unit port of launching antenna array;

Step 5., by electromagnetic field simulation software, obtains the dependent scattering parameter of aerial array, carries out the design of feeding network according to the formula in step 4 after each port excitation calculating, and makes the apportioning cost of each port consistent with the value calculating.

2. the method for designing of microstrip array focusing anteena according to claim 1, is characterized in that: described array comprises face array structure or linear array structure.

3. the method for designing of microstrip array focusing anteena according to claim 1 and 2, is characterized in that: described electromagnetic field simulation software comprises IE3D, HFSS or FEKO Electromagnetic Simulation software.

4. a microstrip array focusing anteena, the antenna element being distributed by array and the feeding network connecting between antenna element form, and it is characterized in that: described feeding network designs by following step:

Step 1. is placed an antenna with transmission antenna unit same size as receiving antenna at the expection focal position of emitting antenna, and receiving antenna and emitting antenna form a wireless transmitting system;

The scattering parameter matrix of the described wireless transmitting system of step 2. definition is as follows:

$\left[\begin{array}{c}\left[b_t\right]\\ \left[b_r\right]\end{array}\right]=\left[\begin{array}{cc}\left[S_{\mathrm{tt}}\right]& \left[S_{\mathrm{tr}}\right]\\ \left[S_{\mathrm{rt}}\right]& \left[S_{\mathrm{rr}}\right]\end{array}\right]\left[\begin{array}{c}\left[a_t\right]\\ \left[a_r\right]\end{array}\right]$

[a wherein _t]=[a ₁, a ₂..., a _n] ^t, [a _r]=[a _n+1], [b _t]=[b ₁, b ₂..., b _n] ^t, [b _r]=[b _n+1], subscript ' t ' represents emitting antenna, ' r ' represents receiving antenna, a _i(i=1,2 ... n+1) represent normalized incident-wave, b _i(i=1,2 ... n+1) represent normalization reflection wave, S _tt, S _rt, S _tr, S _rrrepresent the S parameter that each is corresponding;

Step 3. definition transfer efficiency T _arrayratio for the power of receiving antenna and the power input of emitting antenna:

$T_{\mathrm{array}}=\frac{\frac{1}{2}({\left|\right[b_r\left]\right|}^2-{\left|\right[a_r\left]\right|}^2)}{\frac{1}{2}({\left|\right[a_t\left]\right|}^2-{\left|\right[b_t\left]\right|}^2)};$

The excitation amplitude that step 4. calculates each transmitter unit by following formula is followed phase place:

[A][a _t]=T _array[B][a _t]

Wherein

[a _t] be the excitation of each unit port of launching antenna array;

Step 5., by electromagnetic field simulation software, obtains the dependent scattering parameter of aerial array, carries out the design of feeding network according to the formula in step 4 after each port excitation calculating, and makes the apportioning cost of each port consistent with the value calculating.

5. microstrip array focusing anteena according to claim 4, is characterized in that: the feeding classification of described feeding network comprises coaxial feed or limit feedback mode.

6. according to the microstrip array focusing anteena described in claim 4 or 5, it is characterized in that: described array comprises face array structure or linear array structure.

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