CN101308957A - Power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe - Google Patents

Abstract

Disclosed is a circularly polarized stacked microstrip antenna array with broad band, capacitance compensation, which is fed through a probe. A first medium substrate(2), a first support(4a), a second medium substrate(3), a second support(4b), a feed-in network(5), a feed-in cable(6) and a feed-in metal probe(33)are sequentially arranged inside an antenna shield. An parasitic appended patch(21) is arranged at the inner side of the first medium substrate; one side of the second medium substrate, which contacts with the first support(4a), is provided with a feed-in appended patch(31) and the other side is provided with a capacitance compensation metal appended patch(32); the output port of the feed-in network(5) is connected with the feed-in cable(6); the feed-in network(5) is welded with the feed-in metal probe(33)through the capacitance compensation metal appended patch(32). The invention introduces capacitance compensation, laminated structure and low dielectric constant to broaden the bandwidth of the microstrip antenna, making the relative bandwidth of the antenna reaching up to 20% and circular polarization ratio be less than 3dB within the range of the broadband.

Description

Power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe

Technical field

The present invention relates to the antenna technology of wireless communication field, particularly the occasion that broadband character and circular polarization characteristics are had relatively high expectations.

Background technology

Microstrip antenna has low section, be easy to plurality of advantages such as batch process, but its intrinsic narrow-band characteristic (general relative bandwidth is less than 5%) has limited its range of application.When microstrip antenna is formed array according to certain way, can improve gain, but because the influence of unfavorable factors such as feeding network, the frequency band of antenna array is narrower than the unit of group battle array.Simultaneously, can produce bigger signal fadeout on the high speed dynamic carrier, have remarkable advantages on mobile vehicle so circular polarized antenna is used because linear polarized antenna uses.

Through patent retrieval, specific as follows with the closely-related relevant patent of content of the present invention: " the broadband circularly polarization microstrip antenna " of the patent No.: ZL03230225.8, disclosed microstrip antenna adopt the method that loads the parasitic radiation ring that the beamwidth of antenna is extended to 2% by 1%." wide-band microstrip aerial " of the patent No.: ZL200320123742.0, disclosed microstrip antenna adopts tuning method widening frequency band, but how many not mentioned concrete bandwidth is, and this microstrip antenna is a linear polarization." wide-band microstrip aerial " of the patent No.: ZL200420081255.7, disclosed microstrip antenna adopt oblique L type feed structure that bandwidth is extended to 37%, and this microstrip antenna is a linear polarization." the small wide frequency microstrip antenna " of the patent No.: ZL200420081256.1, disclosed microstrip antenna adopt three-dimensional Y type feed structure and short circuit wall construction that bandwidth is extended to 54%, and this microstrip antenna is a linear polarization.Owing to adopt unsymmetric structure, and circular polarized antenna has strict demand to the symmetry of antenna structure, causes radiation pattern asymmetric, and cross polarization is risen.Number of patent application: 200710072675.7 " half U type open slot overlapping wide frequency band micro band antenna ", disclosed microstrip antenna adopts laminated construction and carry out U type fluting on paster, bandwidth is extended to 19.5%, this microstrip antenna is a linear polarization, because the U type notching construction on paster surface, make the directional diagram symmetry variation of antenna, cross polarization simultaneously improves.Number of patent application: 200710099065.6 " a kind of method for designing of double frequency round polarized laminated micro band antenna ", disclosed microstrip antenna adopt laminated construction to realize two-frequency operation, do not possess non-broadband character.

Adopt a kind of or two kinds of circular polarization microstrip antenna widening frequency band technology realize than being easier in engineering, but because influencing each other between the various broadening technology, therefore adopt two or more technology in engineering, to realize relatively difficulty, even sometimes broadening bandwidth, but be difficult for to obtain good circular polarization characteristics.

In sum, adopt the document of capacitance compensation technology broadening microstrip antenna not see, adopt laminated construction to realize that the document of double frequency-band has report, do not adopt laminated construction to realize wide band document but see.Comprehensive capacitance compensation, laminated construction and the low-k three technology broadening microstrip antenna bandwidth of adopting do not seen bibliographical information.

Summary of the invention

Technical solution problem of the present invention is: provide a kind of relative bandwidth greater than 20%, the circular polarization axial ratio is less than the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of 3dB in the broad frequency range.

Technical solution of the present invention is: power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe comprises radome, two layer medium substrate, two-layer support, feeding network, feeder cable and metal probe; In radome, be followed successively by first medium substrate, first support, second medium substrate, second support and the feeding network; The main effect of two-layer support is that medium substrate is supported with fastening, and feeding network is used for two microband antenna units are carried out power division and realize circular polarization; The parasitic patch that the inner crest face of first medium substrate is useful on the broadening bandwidth and carries out electromagnetic radiation; Second medium substrate and first supports the one side that contacts and is useful on the feed paster that carries out electromagnetic radiation, and another side is useful on the capacitance compensation metal patch of broadening bandwidth; The delivery outlet of feeding network connects feeder cable, and feeding network is connected by the feed metal probe with capacitance compensation metal patch below second medium substrate.

Described first medium substrate and second medium substrate are relative dielectric constant 1＜ε _r＜6 microwave board.

Described first medium substrate and second medium substrate are that relative dielectric constant is 2.2 microwave board.

Described feed paster and parasitic patch are metal patch, are shaped as squarely, and its length of side is:

$a=\frac{c}{2f\sqrt{{\mathrm{\ϵ}}_r}}$

Wherein, c is the free space light velocity, and f is an operating frequency of antenna, the GHz of unit, ε _rBe the Supporting Media relative dielectric constant.

Described feed paster and parasitic patch are metal patch, are shaped as roundly, and its radius is:

$r=\frac{8.794}{f\sqrt{{\mathrm{\ϵ}}_r}}$

Wherein, f is an operating frequency of antenna, the GHz of unit, ε _rBe the Supporting Media relative dielectric constant.

The diameter of described capacitance compensation metal patch is determined in accordance with the following methods:

(1) determines the inductance that feed probes is introduced

$\mathrm{Lp}=\frac{{60h}_1}{c}\ln \left(\frac{c}{\mathrm{\π\γ}{d}_{p}f\sqrt{{\mathrm{\ϵ}}_{r1}}}\right)$

γ is Euler (Euler) constant in the formula, d _pBe probe diameter actual value, h ₁Be the height of medium foam, c is the free space light velocity, ε _R1Be the dielectric constant of medium foam, f is the operating frequency of entire antenna, f=(f ₁+ f ₂)/2, wherein f ₁Be feed patch resonant frequency, f ₂Be the parasitic patch resonance frequency;

(2) in order to obtain good compensation effect, should satisfy condition

ω ²LpC _p＝1

ω is an antenna operating angle frequency in the formula, and Lp is the probe inductance value, C _pBe compensation patch capacitor value;

(3) determine the diameter D of building-out capacitor paster by iterative method by following transcendental equation

$C_p={\mathrm{\&epsiv;}}_0{\mathrm{\&epsiv;}}_{r2}[\frac{D^2}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A20081011487800151.png"\; state="\{\{state\}\}">h</figure-callout>}}_2}+2.257D\ln \left(\frac{0.429D}{h_2}\right)]$

ε in the formula _R2=2.2 is the dielectric constant of dielectric-slab, h ₂=0.8mm is the thickness of dielectric-slab.Described first support and second is supported for relative dielectric constant scope 1＜ε _r＜1.1 medium foam.

Described first supports and second to be supported for relative dielectric constant be 1.05 medium foam.

Described feeding network is that relative dielectric constant is scope 4＜ε _r＜15 feeding network microwave board.

Described feeding network is that relative dielectric constant is 9.6.

Power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe operation principle of the present invention is:

The first, the bandwidth of coming the broadening microstrip antenna by the lamination mount technology.Concrete method adopts double-deck microband paste exactly, and lower floor is the feed paster, and the upper strata is the coupling parasitic patch.Size and their spacings separately by the two-layer paster of reasonably optimizing, thereby reach the purpose of widening frequency band, the standing-wave ratio relative bandwidth that is about to antenna is made as optimization aim, change the length of side and the spacing of two pasters respectively in certain limit, one group of parameter of relative bandwidth maximum is decided to be the optimal design value.

The second, by capacitor compensating probe feed widening frequency band.Owing to adopt probe feed, the general equivalence of probe is an inductance, if at feed paster back side annex electric capacity paster, can the inductance of probe be compensated, thereby reach the purpose of widening frequency band, the size of electric capacity mainly by the size decision of electric capacity paster, need be optimized its size (radius), and the frequency that it is big or small and designed is relevant with the dielectric constant of used medium.After calculating the theoretical value of capacitance compensation paster diameter, about this theoretical value, adjust the variation of the observation beamwidth of antenna slightly and get final product, choose optimum value as design result.

The 3rd, by selecting the microwave base plate widening frequency band of low-k for use.For microstrip antenna, the medium substrate dielectric constant that it adopts more little (low), its bandwidth is wide more.It is 2.2 dielectric-slab that the two layer medium substrate of this antenna all adopts dielectric constant, packing material between the two-layer paster is that dielectric constant is 1.05 Special Foam support, the effective dielectric constant of entire antenna medium is very low like this, thereby reaches the purpose of widening frequency band.The relative dielectric constant minimum of microwave current plate is generally 2.2, is generally less than 6 during selection; The relative dielectric constant minimum of foam support is 1.05, if requirement is not very harsh to architectural characteristic, can be changed to air (dielectric constant is 1).

The present invention compared with prior art has following advantage:

1, owing to comprehensive adopt above-mentioned three kinds of broadening microstrip antenna band technology, antenna of the present invention can reach more than 20% relative bandwidth bandwidth broadening greatly.

2, owing to adopt double-fed point feeding technique, make two excitation port keep quadrature in broad frequency range, the circular polarization axial ratio is less than 3dB in the broad frequency range.

3, the broadband character of antenna of the present invention has good consistency.Because the design adopts sandwich construction, structure is comparatively complicated, but electrical quantity of selecting for use and structural parameters are comparatively rationally moderate, so the variation of parameter is less to the antenna characteristics influence, so through the test of a plurality of antennas, its broadband character has good consistency.

Description of drawings

Fig. 1 is a structure chart of the present invention;

The front elevation that Fig. 2 supports for the present invention first;

The front elevation that Fig. 3 supports for the present invention second;

The back view that Fig. 4 supports for the present invention second;

Fig. 5 is feeding network figure of the present invention;

Fig. 6 is standing-wave ratio of the present invention (VSWR) bandwidth figure;

Fig. 7 is normalization measurement direction figure of the present invention.

Embodiment

The invention will be further described below in conjunction with accompanying drawing.

As shown in Figure 1, power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe comprises radome 1, two layer medium substrate, two-layer support, feeding network 5 and feeder cable 6; The main effect of two-layer support is that the microwave-medium substrate is supported with fastening, and feeding network 5 is used for two microband antenna units are carried out power division and realize circular polarization.

As Fig. 2, Fig. 3, shown in Figure 4, the inner crest face of first medium substrate 2 has parasitic patch 21; The top of second medium substrate 3 is feed paster 31, is capacitance compensation metal patch 32 below.In radome 1, be followed successively by first medium substrate 2, first from left to right and support 4a, second medium substrate 3, second support 4b and the feeding network 5; Capacitance compensation metal patch 32 below the delivery outlet welding feeder cable 6 of feeding network 5, the feeding network layer and second medium substrate 3 is welded to connect by feed metal probe 33.

First medium substrate 2 and second medium substrate 3 are relative dielectric constant 1＜ε _r＜6 microwave board.If relative dielectric constant is greater than 6, then the bandwidth of antenna can obviously reduce, and 1 is the theoretical value of free space.In the present embodiment, it is 2.2 microwave board that first medium substrate 2 and second medium substrate 3 are all selected relative dielectric constant for use.

Parasitic patch 21 and feed paster 31 are metal patch, and metal can aluminium or electric conductivity good metal such as copper, selects metallic copper in the present embodiment for use.Its size is mainly decided by the operating frequency and the dielectric constant of antenna.In the present embodiment, metal patch is round, and its radius is $r=\frac{8.794}{f\sqrt{{\mathrm{\&epsiv;}}_r}}=0.25$ Centimetre, wherein f is that operating frequency of antenna is got 3.8GHz, ε _r=2.2 is the Supporting Media relative dielectric constant.If metal patch is square, its length of side is $a=\frac{c}{2f\sqrt{{\mathrm{\&epsiv;}}_r}},$ C is the free space light velocity.

If feed paster 31 resonance frequencys are f ₁, parasitic patch 21 resonance frequencys are f ₂, then the resonance frequency of entire antenna (operating frequency) is f=(f ₁+ f ₂)/2.Choose feed paster 31 resonance frequency f in the present embodiment ₁=3.6GHz, parasitic patch 21 resonance frequency f ₂=4.0GHz.

Because the inductance that feed metal probe 33 is introduced is

$\mathrm{Lp}=\frac{{60h}_1}{c}\ln \left(\frac{c}{\mathrm{\&pi;\&gamma;}{d}_{p}f\sqrt{{\mathrm{\&epsiv;}}_{r1}}}\right)$

γ is Euler (Euler) constant in the formula, d _pBe probe diameter actual value, h ₁Be the height of medium foam, ε _R1Dielectric constant for the medium foam.

In order to obtain good compensation effect, should satisfy condition:

ω ²L _pC _p＝1

Determine the diameter D of building-out capacitor paster 32 by iterative method with following transcendental equation

$C_p={\mathrm{\&epsiv;}}_0{\mathrm{\&epsiv;}}_{r2}[\frac{D^2}{{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A20081011487800151.png"\; state="\{\{state\}\}">h</figure-callout>}}_2}+2.257D\ln \left(\frac{0.429D}{h_2}\right)]$

ε in the formula ₀Be dielectric constant of air absolute value, ε _R2=2.2 is the dielectric constant of dielectric-slab, h ₂=0.8mm is the thickness of dielectric-slab.

Calculate the diameter of the building-out capacitor paster in the present embodiment: D=0.5 centimetre.

It is the medium foam that the first support 4a and second supports 4b, and its relative dielectric constant span is 1＜ε _r＜1.1, if dielectric is greater than 1.1 relatively, then the bandwidth of antenna can obviously reduce.In the present embodiment, first supports 4a and second supports 4b to select relative dielectric constant for use is 1.05 PMI (metering system acid imide) medium foam.

Feeding network 5 is relative dielectric constant scope 4＜ε _r＜15 feeding network microwave board.If relatively dielectric is greater than 15 for its value, then the feeding network loss increases greatly, and the width of circuit can attenuate, and may cause machining accuracy to realize.In the present embodiment, feeding network 5 is 9.6 feeding network microwave board for relative dielectric constant.

Feeder cable 6 requires as far as possible away from microstrip feed network 5, in order to avoid it is impacted.

Fig. 6 is standing-wave ratio of the present invention (VSWR) bandwidth figure.Fig. 7 is normalization measurement direction figure of the present invention.By among Fig. 6, Fig. 7 as can be seen this example antenna standing wave ratio bandwidth (VSWR＜2) scope be 3.4GHz～4.35GHz, relative bandwidth is 24.5%, its antenna pattern is two results after the unit group battle array.

Claims (10)

1, power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe is characterized in that: comprise radome (1), two layer medium substrate, two-layer support, feeding network (5), feeder cable (6) and feed metal probe (33); In radome (1), be followed successively by first medium substrate (2), first and support (4a), second medium substrate (3), second support (4b) and the feeding network (5); The main effect of two-layer support is that medium substrate is supported with fastening, and feeding network (5) is used for two microband antenna units are carried out power division and realize circular polarization; The parasitic patch (21) that the inner crest face of first medium substrate (2) is useful on the broadening bandwidth and carries out electromagnetic radiation; What second medium substrate (3) and first supported that one side that (4a) contact is useful on electromagnetic radiation posts feed paster (31), and another side is useful on the capacitance compensation metal patch (32) of broadening bandwidth; The delivery outlet of feeding network (5) connects feeder cable (6), and feeding network (5) is connected by feed metal probe (33) with capacitance compensation metal patch (32) on second medium substrate (3).

2, according to the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of claim 1, it is characterized in that: described first medium substrate (2) and second medium substrate (3) are relative dielectric constant 1＜ε _r＜6 microwave board.

3, according to the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of claim 1 or 2, it is characterized in that: described first medium substrate (2) and second medium substrate (3) are 2.2 microwave board for relative dielectric constant.

4, according to the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of claim 1, it is characterized in that: described parasitic patch (21) and feed paster (31) are metal patch, are shaped as square, and its length of side is:

$a=\frac{c}{2f\sqrt{{\mathrm{\&epsiv;}}_r}}$

Wherein, c is the free space light velocity, and f is an operating frequency of antenna, the GHz of unit, ε _rBe the Supporting Media relative dielectric constant.

5, according to the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of claim 1, it is characterized in that: described feed paster and parasitic patch are metal patch, are shaped as roundly, and its radius is:

$r=\frac{8.794}{f\sqrt{{\mathrm{\&epsiv;}}_r}}$

Wherein, f is an operating frequency of antenna, the GHz of unit, ε _rBe the Supporting Media relative dielectric constant.

6, according to the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of claim 1, it is characterized in that: the diameter of described capacitance compensation metal patch (32) is determined in accordance with the following methods:

(1) determines the inductance that feed metal probe (33) is introduced

$\mathrm{Lp}=\frac{60h_1}{c}\ln \left(\frac{c}{\mathrm{\&pi;\&gamma;}{d}_{p}f\sqrt{{\mathrm{\&epsiv;}}_{r1}}}\right)$

γ is an Euler's constant in the formula, d _pBe feed metal probe diameter actual value, h ₁Be the height of medium foam, c is the free space light velocity, ε _R1Be the dielectric constant of medium foam, f is the operating frequency of entire antenna, f=(f ₁+ f ₂)/2, wherein f ₁Be feed patch resonant frequency, f ₂Be the parasitic patch resonance frequency;

(2) answer building-out capacitor C in order to obtain good compensation effect, to make _pMeet the following conditions:

ω ²L _pC _p＝1

ω is the angular frequency of antenna work in the formula, and Lp is the inductance value of metal probe;

(3) determine the diameter D of building-out capacitor paster by iterative method by following transcendental equation

$C_p={\mathrm{\&epsiv;}}_0{\mathrm{\&epsiv;}}_{r2}[\frac{D^2}{h_2}+2.257D\ln \left(\frac{0.429D}{h_2}\right)]$

ε in the formula _R2=2.2 is the dielectric constant of dielectric-slab, h ₂=0.8mm is the thickness of dielectric-slab.

7, according to the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of claim 1, it is characterized in that: described first supports (4a) and second is supported for relative dielectric constant scope 1＜ε _r＜1.1 medium foam.

8, according to the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of claim 1 or 7, it is characterized in that: described first support (4a) and second support (4b) are 1.05 medium foam for relative dielectric constant.

9, according to the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of claim 1, it is characterized in that: described feeding network (5) is scope 4＜ε for relative dielectric constant _r＜15 feeding network microwave board.

10, according to the power feed stacked microstrip antenna array with circular polarized wide-band capacitor compensating probe of claim 1 or 9, it is characterized in that: described feeding network (5) is the feeding network microwave board of relative dielectric constant 9.6.

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