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

Abstract

The invention provides a novel design method of a micro-strip array focusing antenna and the designed micro-strip array focusing antenna so as to overcome the shortcoming that the focusing effect is unsatisfactory or a large number of side lobes exist in an existing focusing antenna design method. The coupling effect of an antenna unit is taken into consideration, and obtained phase distribution exactly meets secondary spherical wave distribution required by the design of the focusing antenna; meanwhile, transmission efficiency can be maximized, the designed focusing antenna hardly has any side lobe and has the optimal amplitude phase distribution, the effective focusing distance is remarkably prolonged, and transmission efficiency is remarkably improved.

Description

The method for designing of microstrip array focusing anteena and microstrip array focusing anteena

Technical field

The invention belongs to flat plane antenna design field, the microstrip array focusing anteena that especially relates to the new design method of the focusing anteena that a kind of degree of accuracy is higher and design by the method.

Background technology

Microwave is widely known by the people already as a kind of means of communication, and has obtained develop rapidly in recent years.Microwave is suggested in 19th century first as the means of power delivery, and has carried out preliminary experimental study.Microwave is the wireless penetration that has realized power delivery as the advantage of the means of power delivery, and this is all with practical value in a lot of occasions.Play people the fifties in last century with regard to the transport issues of the electromagnetic energy that begun one's study, and the transmission means using electromagnetic wave as energy, this wireless delivery of energy mode has obtained develop rapidly from the seventies in last century, for example the terrestrial microwave transmission system that works in S-band has been demonstrated in the jet laboratory of California Inst Tech USA, and the helicopter of powering by microwave.In the later stage eighties, the emphasis of delivery of energy has turned to space movable, and frequency of operation also turns to Ka wave band and F wave band from S-band.Microwave power transmission is that the sun power that satellite or space workbench are collected is defeated by satellite or ground in the main application of space, and this is a costly engineering, but the economic benefit of bringing is also very considerable.

Indiffusion when guaranteeing that electromagnetic wave energy transmits in space, electromagnetic wave must can focus on receiving trap as light, from the focusing analogy of light, learns, and for electromagnetic wave is focused on, the phase place of the bore of emitting antenna must be that sphere distributes.The eighties of last century initial stage sixties, Goubao, Shermen, the people such as Borigiotti have done a large amount of work to the focus issues of aperture antenna, have established the theoretical foundation of electromagnetic wave delivery of energy.The theory that electromagnetic wave focuses on not only can be for microwave power transmission, and can be for radar and microwave directed energy weapon.Concerning microwave directed energy weapon, its effect is to make target reach maximum in the distribution of current of interested part; Concerning radar, its role is to improve echo strength.Can be applied to microwave induced high temperature medically, energy maximum possible be focused on to cancerous issue and carry out high-temperature heating, and its health tissues is not around constituted a threat to simultaneously.

Traditional focusing anteena is by put a dielectric lens before electromagnetic horn, this class focusing anteena has high secondary lobe near focussing plane, obviously the result of this class focusing anteena is not very good, and the common volume of this class focusing anteena is all very large, and design is very difficult, also be not easy to realize, cost is very high simultaneously, can not meet the widespread use of engineering.

M.Bogosanovic has provided the out of phase method for designing of a kind of constant amplitude, and phase place meets conic surface wavelength-division cloth, and amplitude remains unchanged, and from experiment effect, it is not very good near focal position, having a large amount of secondary lobes, focusing effect.

Shaya Karimkashi has provided a kind of based on Dao Erfu---the method for the design focusing anteena that Qie Erxuefu distributes, be not homophases of different width, wherein amplitude meets Qie Erxuefu distribution, and phase place meets conic surface wavelength-division cloth, from experimental result, this method for designing dropped to secondary lobe-below 20dB, resulting near field distribution figure is also fine simultaneously, but there is an obvious deficiency, the physical location that is exactly focus point is larger with the error ratio between emulation focal position, focal position is 200mm in theory, and actual focusing distance has only reached 60mm, obviously such method for designing is still not ideal enough.Therefore, study a kind of design proposal of novel microstrip array focusing anteena very necessary and have a considerable practical significance.

Summary of the invention

Undesirable and there is the defect of a large amount of secondary lobes for focusing effect in existing focusing anteena method for designing, the present invention proposes a kind of method for designing and microstrip array focusing anteena of novel microstrip array focusing anteena, the focusing anteena of designing does not almost have secondary lobe and has optimum range PHASE DISTRIBUTION.

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

A method for designing for microstrip array focusing anteena, 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.

As a kind of preferred version of the method for designing of microstrip array focusing anteena, described array comprises face array structure or linear array structure.

As a kind of preferred version of the method for designing of microstrip array focusing anteena, described electromagnetic field simulation software comprises IE3D, HFSS or FEKO Electromagnetic Simulation software.

A microstrip array focusing anteena, the antenna element being distributed by array and the feeding network connecting between antenna element form, and 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.

As a kind of preferred version of microstrip array focusing anteena, the feeding classification of described feeding network comprises coaxial feed or limit feedback mode.

As a kind of preferred version of microstrip array focusing anteena, described array comprises face array structure or linear array structure.

Compared with prior art, the method for designing of new focusing anteena provided by the invention and the focusing anteena designing according to the method, the coupling effect of antenna element is taken into account, the PHASE DISTRIBUTION obtaining just can meet the desired conic surface wavelength-division of design focusing anteena cloth, transfer efficiency can be accomplished to maximum simultaneously, effectively focusing distance and transfer efficiency are all significantly increased, and almost there is no secondary lobe.

Accompanying drawing explanation

Fig. 1 is the wireless transmission system architecture schematic diagram that transmitting antenna array and receiving antenna form;

Fig. 2 is wireless transmitting system signal transmission schematic diagram;

Fig. 3 is individual antenna cell schematics;

Fig. 4 is feeding network schematic diagram, wherein numeral 1,2 ..., 17 represent each port;

Fig. 5 is emitting antenna schematic diagram;

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

Fig. 7 be antenna at focussing plane the distribution map of the electric field along X-direction;

Fig. 8 be antenna at focussing plane the distribution map of the electric field along Y direction;

Fig. 9 is the electric-field intensity distribution figure in maximum field intensity density place plane.

Embodiment

Below with reference to specific embodiment, technical scheme provided by the invention is elaborated, should understands following embodiment and only for the present invention is described, is not used in and limits the scope of the invention.

The major issue that focusing anteena design faces is exactly to obtain suitable near-field radiation pattern, make it lower secondary lobe, because higher secondary lobe can affect accuracy and the transfer efficiency of focusing, therefore, reasonably amplitude-phase distribution is the key addressing this problem.

Specifically, the present invention adopts the method for designing of new focusing anteena, comprises the steps:

Step 1. is based on wireless power transmission system, in order to realize maximise transmission efficiency, the emitted energy of emitting antenna focuses on the position of receiving antenna, first antenna element is formed to an array as emitting antenna, expection focal position (with emitting antenna distance be D) antenna with transmission antenna unit same size of placement is as receiving antenna, constructs a wireless transmitting system.In emitting antenna, antenna element is that array distributes, and the array structure here can adopt all types of array antenna structures, for example face array, line array type structure, conformal array array structure etc.Now system can be regarded n+1 port network as shown in Figure 2 as, can be with (n+1) * (n+1) scattering parameter matrix represents.

For example we take design frequency as 2.45GHZ, baseplate material is FR4, thickness is 3mm, 16 antenna elements are example, 16 face array structures that antenna element is 4*4, spacing between unit is 60mm, expection focusing distance is 100mm, aerial array and receiving antenna are placed as shown in Figure 1, the present invention's employing micro-strip paster antenna is as shown in Figure 3 as antenna element, but micro-strip paster antenna should not it must be noted that as restriction of the present invention, conventional antenna element can meet demand of the present invention in the industry.Whole system can be regarded the port network of 16+1 as, and scattering parameter matrix representation is:

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

[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 2. 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 3. 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 4. is by electromagnetic field simulation software (electromagnetic field simulation software can adopt IE3D or the conventional Electromagnetic Simulation software such as HFSS, FEKO), obtain the dependent scattering parameter of aerial array, and then corresponding port best distribution value while obtaining maximum efficiency value according to the transfer efficiency between system, the concrete antenna of take in the present invention is example, and the port excitation obtaining by computing is as shown in table 1:

Table 1

Step 5. is according to the port value obtaining (the excitation amplitude of transmitter unit is with phase place), according to the existing knowledge of transmission line, make full use of the relevant knowledges such as impedance transformer, power splitter, with width, can change amplitude, it is cardinal rule that length can change phase place, the corresponding feeding network of design as shown in Fig. 4, Fig. 5, Fig. 6, makes the apportioning cost of each port consistent with the value calculating before.Wherein each port being connected with antenna (2,3 in Fig. 4 ..., 17) with 50 ohm of input impedance, substitute, in Fig. 4,1 place is feed place, in this example, feed adopts coaxial feed, as required, also can adopt other feeding classifications, as limit feedback mode.

After feeding network designs, 50 ohm of input impedance used in feeding network are replaced to antenna element, thereby antenna element is formed a whole with feeding network.

We obtain the electric field normalization figure (Fig. 6) of the aerial array of the present invention design by Electromagnetic Simulation software and darkroom near-field test, antenna at focussing plane along the distribution map of the electric field (Fig. 7) of X-direction, antenna at focussing plane along the distribution map of the electric field (Fig. 8) of Y direction, the electric-field intensity distribution figure (Fig. 9) of maximum field intensity density place plane.As can be seen from Figure 6 test result and simulation result are more identical, find out that main lobe does not all occur secondary lobe to-35dB in Fig. 7, and in Fig. 8, main lobe does not all occur secondary lobe to-25dB.As can be seen from Figure 9 adopt the actual focusing distance of focusing anteena of method for designing design provided by the invention can reach 80mm, effective focusing distance is compared prior art and is significantly improved, and simultaneously without any secondary lobe, transfer efficiency can reach 30%.

The present invention equally also discloses a kind of microstrip array focusing anteena, comprise transmitting antenna array, the transmitter unit that described transmitting antenna array is distributed by array forms, between described transmitter unit, by feeding network, connect, described feeding network and the method for designing by microstrip array focusing anteena provided by the invention design.

The disclosed technological means of the present invention program is not limited only to the disclosed technological means of above-mentioned embodiment, also comprises the technical scheme being comprised of above technical characterictic combination in any.It should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications are also considered as protection scope of the present invention.

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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