CN103793573A - Method for designing Hilbert fractal ultrahigh frequency antenna - Google Patents
Method for designing Hilbert fractal ultrahigh frequency antenna Download PDFInfo
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- CN103793573A CN103793573A CN201410054521.5A CN201410054521A CN103793573A CN 103793573 A CN103793573 A CN 103793573A CN 201410054521 A CN201410054521 A CN 201410054521A CN 103793573 A CN103793573 A CN 103793573A
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Abstract
The invention discloses a method for designing a Hilbert fractal ultrahigh frequency antenna. The method includes the steps of arranging a grounding board and a Hilbert fractal wire layer on the two sides of a dielectric substrate respectively, enabling the lengths of parallel dual wires, short circuit terminals and additional wire sections to serve as parameters when the sizes of all parts of wire sections inside the wire layer are determined, meanwhile, considering the wire width, the dielectric thickness and the dielectric constant to build calculation equations of the resonance frequency and the standing-wave ratio of the antenna, carrying out simulating optimization on the parameters within the available ranges of the resonance frequency and the standing-wave ratio to obtain optimal values of the lengths of the three kinds of wire sections and the widths of the wire sections, and finally manufacturing the Hilbert fractal ultrahigh frequency antenna according to the simulation results. According to the method, the Hilbert fractal ultrahigh frequency antenna is optimized by changing the lengths of the parallel dual wires, the short circuit terminals and the additional wire sections, and the collecting effect of the antenna on partial discharge ultrahigh frequency signals of electrical equipment is greatly improved.
Description
Technical field
The present invention relates to a kind ofly for gathering the design and optimization method of quadravalence Hilbert fractal antenna of power equipment local discharge superhigh frequency signal, belong to antenna technical field.
Background technology
Along with developing rapidly of electric system, the safe and stable operation of power equipment is more and more subject to people's attention.In recent years, power equipment accident happens occasionally, and shelf depreciation is the general features that accident occurs early stage.Therefore, utilize local discharge on-line monitoring device to carry out Real-Time Monitoring to the local discharge signal of power equipment, make plant maintenance personnel understand in time the ruuning situation of equipment, find in time and get rid of the latent defect of power equipment, to avoiding the generation of power equipment accident significant.
Hilbert fractal antenna is local discharge signal receiving element conventional in local discharge on-line monitoring device, Hilbert fractal antenna is the modular design in current all antenna types, be made up of medium substrate, conductor layer and ground plate, wherein conductor layer is the fractal shape of Hilbert.Fig. 1 is one to quadravalence Hilbert fractal shape schematic diagram, Hilbert is fractal can be described as: square is divided into four little squares of single order, connect successively the square center in the lower left corner, the upper left corner, the upper right corner, the lower right corner, obtain a somatotype unit (being that single order Hilbert is fractal); Little each single order square is divided into respectively to four little squares of second order, repeat said process, the fractal unit of the high-order opening direction generating observe certain rule (in Fig. 1, the opening direction of the fractal unit of high-order in the lower left corner, the upper left corner, the upper right corner, the lower right corner is followed successively by: left, under, under, the right side), and according to the opening of the somatotype unit that is specifically linked in sequence (being the fractal unit of the high-order opening that connects successively the lower left corner, the upper left corner, the upper right corner, the lower right corner in Fig. 1), finally just obtain one and can fill up whole foursquare curve, Here it is Hibert curve.In the high-order fractal curve that the conductor layer of Hilbert fractal antenna forms, two paired limits are that (fine line in Fig. 2 a) for parallel double conducting wire, the limit that connects parallel double conducting wire is that (b), the limit that somatotype unit is connected to complete curve is that (thick dashed line in Fig. 2 c) for additional guide line segment to the heavy line in Fig. 2 to short circuit termination.
Fractal Hilbert antenna ratio dipole antenna is more suitable in multiband or broadband application occasion; If keep same resonance frequency, Hilbert fractal antenna length is about 1/7 of same dipole antenna, therefore takes up room very little on the other hand.
At present, mainly contain two kinds for the Hilbert fractal antenna that gathers power equipment local discharge superhigh frequency signal by exponent number classification, one is three rank Hilbert fractal antennas, the 2nd, and quadravalence Hilbert fractal antenna.But all there is obvious design defect in existing Hilbert fractal antenna: the length of parallel double conducting wire, short circuit termination and the additive wire of Hilbert fractal antenna conducting line segment all equates, the difference of having ignored the impact that dissimilar conducting line segment produces signal, therefore can not obtain desirable collection effect.
Summary of the invention
The object of the invention is to the drawback for prior art, a kind of Hilbert method for designing of fractal ultra-high frequency antenna is provided, to improve the collection effect of Hilbert fractal antenna to power equipment local discharge superhigh frequency signal.
Problem of the present invention realizes with following technical proposals:
The method for designing of the fractal ultra-high frequency antenna of a kind of Hilbert, described method arranges respectively ground plate and the fractal conductor layer of Hilbert in the both sides of medium substrate, while determining conductor layer inside conductor section each several part size by parallel double conducting wire, the length of short circuit termination and additional guide line segment is classified parameter as, consider conductor width simultaneously, dielectric thickness and medium specific inductive capacity, set up the accounting equation of resonance frequency and the standing-wave ratio (SWR) of antenna, and in the usable range of resonance frequency and standing-wave ratio (SWR), above-mentioned parameter is optimized, obtain the optimum value of three class conducting line segment length and conducting line segment width, finally make Hilbert fractal antenna according to optimum results.
The method for designing of the fractal ultra-high frequency antenna of above-mentioned Hilbert, the fractal ultra-high frequency antenna of described Hilbert is quadravalence, its specific design step is as follows:
A. by traditional definition, the conducting line segment of antenna is divided into 64 pairs of parallel double conducting wires, 64 short circuit terminations and 63 additive wires, the length of parallel double conducting wire, short circuit termination, additive wire represents with M, N, A respectively; The width of three class conducting line segments is identical, represents with W;
B. set up antenna resonant frequency f
raccounting equation with standing-wave ratio (SWR) VSWR:
Wherein, c is the light velocity, c=3 × 10
8m/s, k ∈ { 0, R
+; Z
cfor the intrinsic impedance of free space, Z
c=120 π Ω; ω is angular frequency, ω=2 π f, and β is phase constant, β=2 π λ, the logarithm that P is parallel double conducting wire, P=4
n-1=64; S is all conducting line segment length of short circuit termination summation, S=4
n-1× N; D is additive wire segment length summation, D=(4
n-1-1) × A, n is the fractal exponent number of Hilbert, n=4; μ
0for permeability of vacuum, μ
0=4 π × 10
-7hm
-1, λ is for receiving electromagnetic wavelength;
for the characteristic impedance of feeder line;
C. for different W, M, N, A value, calculates respectively antenna resonant frequency f
rwith standing-wave ratio (SWR) VSWR, then according to resonance frequency f
rdetermine W with the usable range of standing-wave ratio (SWR) VSWR, M, N, the optimum value of A;
D. according to W, M, N, the optimum value of A is made Hilbert fractal antenna.
The method for designing of the fractal ultra-high frequency antenna of above-mentioned Hilbert, the material of described medium substrate is glass-epoxy copper-clad plate flame resistant material (FR4), and thickness is 1.6mm, and the material of described ground plate and conductor layer is copper.
The method for designing of the fractal ultra-high frequency antenna of above-mentioned Hilbert, calculates antenna resonant frequency f
rduring with standing-wave ratio (SWR) VSWR, the value of each parameter is as follows: W initial value is 1mm, and stepping length is 0.5mm, and stop value is 3mm; M, N and A initial value are 2mm, and stepping length is 5mm, and stop value is 6mm.
The present invention has taken into full account the difference of the impact that dissimilar conducting line segment produced to received signal, the length of parallel double conducting wire, short circuit termination and additive wire by changing Hilbert fractal antenna conducting line segment is optimized antenna, has greatly improved the collection effect of Hilbert fractal antenna to power equipment local discharge superhigh frequency signal.
Simulation result is as Figure 11, shown in Figure 12.Simulation result shows all there has been very large improvement according to passband, gain and the directivity parameter of the novel quadravalence Hilbert fractal antenna of method for designing design.Its passband is wider, gains higher, and directivity is also better, delicately receiving antenna local discharge superhigh frequency signal to direction.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the invention will be further described.
Fig. 1 is one to quadravalence Hilbert fractal shape schematic diagram;
Fig. 2 is conducting line segment classification schematic diagram in quadravalence Hilbert fractal antenna;
Fig. 3 is by the front schematic view of the quadravalence Hilbert fractal antenna of the present invention's design;
Fig. 4 is by the schematic rear view of the quadravalence Hilbert fractal antenna of the present invention's design;
Fig. 5 is A-A cut-open view;
Fig. 6 is by the stereographic map of the quadravalence Hilbert fractal antenna of the present invention's design;
Fig. 7 is the result of calculation of i group data in embodiment;
Fig. 8 is the simulation result of i group data in embodiment;
Fig. 9 is the result of calculation of j group data in embodiment;
Figure 10 is the simulation result of j group data in embodiment;
Figure 11 is the standing-wave ratio (SWR) optimization of profile result of designing antenna;
Figure 12 is gain and the directivity control result of designing antenna.
In figure, each list of reference numerals is: 1, medium substrate, 2, conductor layer, 3, ground plate.
In literary composition, each symbol inventory is: M, parallel double conducting wire length, N, short circuit termination length, A, additive wire length, the width of W, conducting line segment, f
r, antenna resonant frequency, VSWR, antenna standing wave ratio, c, the light velocity, Z
c, free space intrinsic impedance, ω, angular frequency, β, phase constant, the logarithm of P, parallel double conducting wire, S, all conducting line segment length of short circuit termination summation, D, additive wire segment length summation, the fractal exponent number of n, Hilbert, μ
0, permeability of vacuum, λ, receive electromagnetic wavelength,
, feeder line characteristic impedance.
Embodiment
With the example that is designed to of quadravalence Hilbert fractal antenna, embodiment is mainly that application HFSS software optimization function is carried out correlation parameter optimization.Three kinds of conducting line segment length of antenna are set to respectively to M, N, A, and conductor width is set is W, dielectric substrate thickness is d, the choice of material FR4 of medium substrate, conductor layer is copper, and choosing port1 point in Fig. 3, Fig. 4 is that feeding point is to reach the effect of impedance matching.Set up HFSS realistic model according to above parameter setting.By the optimal design module of HFSS, to (2mm, 8mm) the parallel wire length M in scope, short circuit termination length N, additive wire segment length A and (1mm, 3mm) the conductor width W in scope, (0.6mm, 2mm) the dielectric thickness d in scope is optimized design, the optimum results obtaining, optimum dimension is: parallel wire segment length M=4mm, short circuit termination length N=3mm, additive wire segment length A=6mm, conductor width W=2mm, dielectric substrate thickness d=1.6mm, length of side L1 (the horizontal length of side in Fig. 3) and length of side L2 (the longitudinal length of side in Fig. 3) that whole antenna is last are: L1=7*A+8*N=66mm, L2=7*A+M+7*N=70mm.
Antenna layers of material is configured to: conductor layer is copper material, and medium substrate is FR4 glass-epoxy copper-clad plate flame resistant material (FR4), and ground plate is copper material, dielectric substrate thickness d=1.6mm.
Ultimate principle of the present invention
(1) set up the computation model of system
M represents the length of antenna parallel conductive line segment, and N represents the length of short circuit termination, and A represents the length of additional guide line segment, and W represents the conductor width of antenna; D represents thickness of dielectric layers, and R represents the diameter of circular excitation port, and r represents the probe aperture diameter through medium substrate.
(2) calculation of parameter
A. the conducting line segment of antenna is divided into parallel double conducting wire, short circuit termination and additive wire three types.
B. set up the accounting equation of antenna correlation parameter.Resonant frequency point is obvious to the properties influence of antenna, therefore by resonant frequency point f
ranalyze the not same-action of three kinds of conducting line segments as main characteristic parameters.F
rcomputing formula is as follows:
Wherein, c is the light velocity, c=3 × 10
8m/s, k ∈ { 0, R
+.Z
cfor the intrinsic impedance of free space, Z
c=120 π Ω.ω is angular frequency, ω=2 π f, and β is phase constant, β=2 π λ, the logarithm that P is parallel double conducting wire, P=4
n-1.S is all conducting line segment length of short circuit termination summation, S=4
n-1× N; D is additive wire segment length summation, D=(4
n-1-1) × A, n is the fractal exponent number of Hilbert.μ
0for permeability of vacuum, μ
0=4 π × 10
-7hm
-1, λ is for receiving electromagnetic wavelength.
The standing-wave ratio (SWR) VSWR of antenna is also the important parameter that affects antenna performance, and it is as follows that standing-wave ratio (SWR) is calculated formula:
Wherein
for the characteristic impedance of feeder line, P is parallel double conducting wire logarithm, in the time that antenna is quadravalence Hilbert fractal antenna, and P=64.
Can obtain by above resonant frequency point and VSWR accounting equation group analysis, three kinds of conducting line segments resonance frequency and VSWR on antenna all has different impacts.
When parallel wire increases, antenna resonant frequency point reduces, and antenna VSWR parameter raises; The short circuit termination length added-time, antenna resonant frequency point reduces, and VSWR parameter reduces; When additive wire length increases, antenna resonant frequency raises, and VSWR parameter is substantially constant.Also can comparative analysis obtain three kinds of conducting line segment gains to antenna and the Different Effects of directivity in addition.When parallel wire increases, antenna gain reduces, but directivity improves; The short circuit termination length added-time, antenna gain is substantially constant, but directivity variation; When additive wire length increases, antenna gain improves, and directivity improves.
C. solution procedure
By above two formula, seek one group of optimum solution, can make quadravalence Hilbert fractal antenna characteristic reach best.Feasible solution arranges as shown in table 1:
The setting of table 1 feasible solution
As shown in table 1, make W, M, N, A that different numerical value is set respectively, W initial value is 1mm, and stepping length is 0.5mm, and stop value is 3mm; M, N and A initial value are 2mm, and stepping length is 5mm, and stop value is 6mm.W, M, N, A choose difference and scope be according to Practical Project can processing dimension and application require to choose.Antenna is in oil-filled transformer casing, and therefore size is unsuitable excessive, and design result diameter should be no more than 100mm, therefore makes the length of M, N, A be less than 6mm.
Each group data is made up of a feasible solution of choosing respectively in W, M, N, A, forms 5 × 9 × 9 × 9=3654 group size to be solved.
Calculating wherein makes antenna performance reach optimum size by choosing.Antenna performance criterion is: f
rwithin the scope of 300MHz-3GHz and less, antenna is better in the characteristic of ultra-high frequency band, and standing wave corresponding to resonant frequency point should be less; VSWR is a curve with collection signal frequency change, therefore need to guarantee that VSWR keeps within the specific limits, conventionally when VSWR<5 is available frequency range, therefore in standing-wave ratio (SWR) VSWR curve, within the scope of 300MHz-3GHz, be less than 5 the scope passband scope corresponding to antenna, in standing-wave ratio (SWR) VSWR, within the scope of 300MHz-3GHz, be less than 5 frequency range wider, the passband of antenna is wider, and the characteristic of antenna is also better.In addition can reference gain and two characteristics of directivity: the larger antenna that gains is as sensor probe, and receiving ability is better; Directivity will be chosen on each receive direction of antenna and all present superperformance, and the sense that all need to accept at antenna of stronger receive direction.
Calculate above two formula according to parameter group to be asked, ask for W, M, N, the optimum value of A.Optimizing example is as follows.
I group is chosen W=1mm, M=2mm, N=2.5mm, A=3mm, substitution f
rwith VSWR computing formula, result of calculation and simulation result are referring to Fig. 7 and Fig. 8.
J group is chosen W=1.5mm, M=4mm, N=3mm, A=5mm, substitution f
rwith VSWR computing formula, result of calculation and simulation result are referring to Fig. 9 and Figure 10.
Under more known j group parameter, based on above criterion, the resonance frequency f of antenna
rbe better than i group with standing-wave ratio (SWR) VSWR characteristic, therefore j group data can be preserved and other data comparisons, repeat searching process, i group data are eliminated.
Through complete computation, available result is that three kinds of conducting line segment width are W=2mm, parallel double conducting wire length M=4mm, short circuit termination length N=3mm, additive wire segment length A=6mm.
W, M in the present invention, the span of N, A can processing dimension according to Practical Project and application require to choose.Antenna is in oil-filled transformer casing, and therefore size is unsuitable excessive, and design result diameter should be no more than 100mm, therefore makes the length of M, N, A be less than 6mm.The pass that antenna width W should meet is:
W<min{M?，N，A}
Be that W should be less than the minimum value in M, N, A three, otherwise the each conducting line segment of antenna can interconnect, destroy original geometry of wire, the performance of antenna is caused to very large negative effect.
The stepping length of W, M, N, A be according in Practical Project can machining precision and the intensity of variation of antenna performance determine.In actual print circuit fabrication process, can not reach arbitrary dimension, general precision is 0.5mm.
The present invention is provided with at the feeding point place of the fractal ultra-high frequency antenna of Hilbert the through hole that runs through ground plate, medium substrate and conductor layer, is connected with ground plate for antenna conductor layer with feeder line, passes the signal along to signal processing and display device that rear end connects.
The characteristic of antenna prioritization scheme:
The Hilbert fractal antenna P.e.c. optimization scheme obtaining according to method for designing, in 0.3GHz-3GHz uhf-range, resonant frequency point reaches four, and standing-wave ratio (SWR) characteristic is good, passband within the scope of 0.3GHz-1GHz is widened to be integrated into exceed 500MHz broadband, three more than 1GHz passbands also all exceed 450MHz.Optimization scheme, its directivity is good, and gain parameter is also greatly improved than the design of conventional wires section equal length.
Claims (4)
1. the method for designing of the fractal ultra-high frequency antenna of Hilbert, it is characterized in that, described method arranges respectively ground plate and the fractal conductor layer of Hilbert in the both sides of medium substrate, while determining conductor layer inside conductor section each several part size by parallel double conducting wire, the length of short circuit termination and additional guide line segment is classified parameter as, consider conductor width simultaneously, dielectric thickness and medium specific inductive capacity, set up the accounting equation of resonance frequency and the standing-wave ratio (SWR) of antenna, and in the usable range of resonance frequency and standing-wave ratio (SWR), above-mentioned parameter is carried out to simulation optimization, obtain the optimum value of three class conducting line segment length and conducting line segment width, finally make Hilbert fractal antenna according to simulation result.
2. the method for designing of the fractal ultra-high frequency antenna of Hilbert according to claim 1, is characterized in that, the fractal ultra-high frequency antenna of described Hilbert is quadravalence, and its specific design step is as follows:
A. by classic method, the conducting line segment of antenna is divided into 64 pairs of parallel double conducting wires, 64 short circuit terminations and 63 additive wires, the length of parallel double conducting wire, short circuit termination, additive wire represents with M, N, A respectively; The width of three class conducting line segments is identical, represents with W;
B. set up antenna resonant frequency f
raccounting equation with standing-wave ratio (SWR) VSWR:
Wherein, c is the light velocity, c=3 × 10
8m/s, k ∈ { 0, R
+; Z
cfor the intrinsic impedance of free space, Z
c=120 π Ω; ω is angular frequency, ω=2 π f, and β is phase constant, β=2 π λ, the logarithm that P is parallel double conducting wire, P=4
n-1=64; S is all conducting line segment length of short circuit termination summation, S=4
n-1× N; D is additive wire segment length summation, D=(4
n-1-1) × A, n is the fractal exponent number of Hilbert, n=4; μ
0for permeability of vacuum, μ
0=4 π × 10
-7hm
-1, λ is for receiving electromagnetic wavelength;
for the characteristic impedance of feeder line;
C. for different W, M, N, A value, calculates respectively antenna resonant frequency f
rwith standing-wave ratio (SWR) VSWR, then according to resonance frequency f
rdetermine W with the usable range of standing-wave ratio (SWR) VSWR, M, N, the optimum value of A;
D. according to W, M, N, the optimum value of A is made Hilbert fractal antenna.
3. the method for designing of the fractal ultra-high frequency antenna of Hilbert according to claim 1 and 2, is characterized in that, the material of described medium substrate is FR4, and thickness is 1.6mm, and the material of described ground plate and conductor layer is copper.
4. the method for designing of the fractal ultra-high frequency antenna of Hilbert according to claim 2, is characterized in that, calculates antenna resonant frequency f
rduring with standing-wave ratio (SWR) VSWR, the value of each parameter is as follows: W initial value is 1mm, and stepping length is 0.5mm, and stop value is 3mm; M, N and A initial value are 2mm, and stepping length is 5mm, and stop value is 6mm.
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| CN201410054521.5A CN103793573B (en) | 2014-02-18 | A kind of method for designing of the fractal ultra-high frequency antenna of Hilbert |
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| CN103793573B CN103793573B (en) | 2016-11-30 |
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| CN104833907A (en) * | 2015-05-27 | 2015-08-12 | 华北电力大学（保定） | System for testing GIS partial discharge and VFTO |
| CN104953260A (en) * | 2015-06-16 | 2015-09-30 | 华北电力大学（保定） | Broadband planar helical antenna for detecting partial discharge of electrical equipment and design method thereof |
| CN105140635A (en) * | 2015-09-10 | 2015-12-09 | 华南理工大学 | Miniature difference feed double-frequency fractal antenna capable of being implanted into human body |
| CN105305062A (en) * | 2015-12-15 | 2016-02-03 | 华北电力大学（保定） | Wunderlich fractal antenna for electric appliance partial discharge ultrahigh-frequency detection and design method |
| CN106650171A (en) * | 2017-01-05 | 2017-05-10 | 重庆大学 | Transformer partial discharge ultrahigh frequency detection Hilbert fractal antenna optimization method |
| CN108598671A (en) * | 2018-05-25 | 2018-09-28 | 重庆大学 | It is a kind of to divide shape unit helical antenna for the detection of transmission line of electricity corona discharge |
| CN114122704A (en) * | 2021-11-22 | 2022-03-01 | 广东电网有限责任公司 | Butterfly antenna and antenna array |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104833907A (en) * | 2015-05-27 | 2015-08-12 | 华北电力大学（保定） | System for testing GIS partial discharge and VFTO |
| CN104833907B (en) * | 2015-05-27 | 2018-09-18 | 华北电力大学（保定） | A kind of measuring system of GIS partial discharge and VFTO |
| CN104953260A (en) * | 2015-06-16 | 2015-09-30 | 华北电力大学（保定） | Broadband planar helical antenna for detecting partial discharge of electrical equipment and design method thereof |
| CN105140635A (en) * | 2015-09-10 | 2015-12-09 | 华南理工大学 | Miniature difference feed double-frequency fractal antenna capable of being implanted into human body |
| CN105305062A (en) * | 2015-12-15 | 2016-02-03 | 华北电力大学（保定） | Wunderlich fractal antenna for electric appliance partial discharge ultrahigh-frequency detection and design method |
| CN106650171A (en) * | 2017-01-05 | 2017-05-10 | 重庆大学 | Transformer partial discharge ultrahigh frequency detection Hilbert fractal antenna optimization method |
| CN108598671A (en) * | 2018-05-25 | 2018-09-28 | 重庆大学 | It is a kind of to divide shape unit helical antenna for the detection of transmission line of electricity corona discharge |
| CN114122704A (en) * | 2021-11-22 | 2022-03-01 | 广东电网有限责任公司 | Butterfly antenna and antenna array |
| CN114122704B (en) * | 2021-11-22 | 2024-04-30 | 广东电网有限责任公司 | Butterfly antenna and antenna array |
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