CN101819237A - Method for discriminating cavity structure periphery electromagnetic environment strength - Google Patents

Abstract

The invention provides a method for discriminating cavity structure periphery electromagnetic environment strength. According to ship design scheme, a ship platform is established in a commercial electromagnetic field simulation software, according to relationship of near far field at the periphery of radiating antenna on the basis of electromagnetic theory, correlation of all the parameters of scatter and the radiating antenna as well as the cavity is constructed, thus primarily judging in which region of the radiating antenna the cavity is located in the shortwave full frequency range of working frequency of radiating antenna; if one part of the cavity is in far field region and the other part is in near field region, the field region of the radiating antenna where the cavity is located is further judged according to frequency of cavity electromagnetic effect. The invention estimates electromagnetic environment strength near cavity structure composed of sensitive devices at the periphery of strong radiation source and provides a reference frame for electromagnetic safety design and electromagnetic protection design of sensitive devices.

Description

The method of discrimination of cavity structure periphery electromagnetic environment strength

Technical field

The present invention relates to the electromagnetic protection field, be specifically related to a kind of method of discrimination of cavity structure periphery electromagnetic environment strength.

Background technology

On the boats and ships platform, the open space that scatterer surrounded (not having clear and definite closed boundary) can be considered a kind of cavity body structure.The scatterer that constitutes cavity body structure is a sensitive equipment.Cavity has amplification to electromagnetic environment, the limit value that the residing electromagnetic environment of sensitive equipment is above standard and stipulates around making, and then cause the Electromgnetic seat problem.

Sensitive equipment and system quantity increase along with various carrier equipments make the carrier platform space day by day crowded, and the electromagnetic hazard problem that the cavity galvanomagnetic effect is brought will be serious day by day.Therefore, tentatively definite at boats and ships platform General layout Plan, under the known prerequisite of the physical dimension of sensitive equipment and substantial radiation source and position, how near the electromagnetic environment strength cavity body structure that is made of sensitive equipment around the substantial radiation source being estimated, is a difficult problem of strengthening sensitive equipment and Electromgnetic seat design of boats and ships platform and electromagnetic protection designed capacity.

Summary of the invention

The technical problem to be solved in the present invention is: provide a kind of method of discrimination of cavity structure periphery electromagnetic environment strength, for the design of the design of sensitive equipment Electromgnetic seat and electromagnetic protection provides reference frame.

The present invention solves the problems of the technologies described above the technical scheme of being taked to be: the method for discrimination of cavity structure periphery electromagnetic environment strength is characterized in that: it comprises following step:

1) according to the Ship Design scheme, in commercial electromagnetic field simulation software, set up the boats and ships platform, comprise radiating antenna and scatterer on the boats and ships platform, around two scatterers, appoint and get a bit as observation point;

2) use commercial electromagnetic field simulation software, obtain the response curve of the electric field intensity of observation point with the radiating antenna frequency of operation, if tangible field intensity spike has appearred in response curve, illustrate that then these two scatterers have constituted cavity body structure, and when the pairing frequency of field intensity spike, the cavity galvanomagnetic effect occurs;

3) scatterer of establishing with the radiating antenna close together is first scatterer, the scatterer far away with the radiating antenna distance is second scatterer, obtain spacing d, the out to out L of radiating antenna of radiating antenna to length a, first scatterer and second scatterer of the air line distance D of first scatterer, first scatterer, all length unit is rice;

4) judge for the first time: judge by following formula cavity is positioned at which kind of place of radiating antenna in the shortwave full frequency band scope of radiating antenna work:

A, if Illustrate that then cavity is in the near field region of radiating antenna;

B, if Illustrate that then cavity is in the far-field region of radiating antenna;

C, if Or

Illustrate that then the part of cavity is in the near field region of radiating antenna, another part is in the far-field region of radiating antenna;

5), differentiate the cavity periphery electromagnetic environment strength according to the judged result first time:

If the place that cavity is in is above-mentioned steps a, cavity then is described, and electric field intensity is bigger on every side, finishes to judge; If the place that cavity is in is above-mentioned steps b, cavity then is described, and electric field intensity is less on every side, but the existence still of cavity galvanomagnetic effect finishes to judge; If the place that cavity is in is above-mentioned steps c, then carries out the second time and judge.

6) judge for the second time: according to the frequency f that the cavity galvanomagnetic effect occurs ', judge the place of cavity radiating antenna of living in when the cavity galvanomagnetic effect occurring, f ' unit is MHz:

D, if

Then explanation cavity this moment is in the near field region;

E, if

Then explanation cavity this moment is in the far-field region;

F, if

And Then the part of explanation cavity this moment is in the near field region of radiating antenna, and another part is in the far-field region of radiating antenna;

7), differentiate cavity structure periphery electromagnetic environment strength according to the result who judges for the second time:

If the place that cavity is in is above-mentioned steps d, electric field intensity is bigger around the cavity; If the place that cavity is in is above-mentioned steps e, the less existence of electric field intensity around the cavity but the cavity galvanomagnetic effect remains unchanged; If the place that cavity is in is above-mentioned steps f, electric field intensity is taken second place around the cavity.

Press such scheme, described commercial electromagnetic field simulation software is a FEKO software.

Press such scheme, include two or more scatterers on the described boats and ships platform.

The electromagnetic theory of institute of the present invention foundation is: the field round radiating antenna can be divided into two main zones, be called near field region or Fresnel (Fresnel) district near the zone of antenna, from radiating antenna far away be called far-field region or fraunhofer (Fraunhofer) district.The interphase in two districts can be taken as radius

In the formula, R represents the distance from the observation point to the antenna; L represents the out to out of antenna; λ represents operation wavelength.According to above-mentioned nearly far field relational expression, made up itself and first scatterer length a, two scatterer spacing d, radiating antennas to the correlativity between the air line distance D of first scatterer, thereby principium identification goes out cavity is positioned at radiating antenna in the shortwave full frequency band scope of radiating antenna frequency of operation which kind of place.

In shortwave full frequency band scope, cavity all is positioned at the near field region of antenna, then satisfies following relational expression:

$\left\{\begin{array}{c}f>\frac{300\&times;(D+a+d)}{2L^2}\&DoubleRightArrow;\frac{300\&times;(D+a+d)}{2L^2}<3\&DoubleRightArrow;(D+a+d)<\frac{L^2}{50}\\ f\&Element;\left[\mathrm{3,30}\right]\end{array}\right.---\left(1\right)$

In the formula, f represents the frequency of operation of radiating antenna.

In shortwave full frequency band scope, cavity all is positioned at the far-field region of antenna, then satisfies following relational expression:

$\left\{\begin{array}{c}f<\frac{300\&times;(D+a)}{{2L}^2}\&DoubleRightArrow;\frac{300\&times;(D+a)}{2L^2}>30\&DoubleRightArrow;(D+a)>\frac{L^2}{5}\\ f\&Element;\left[\mathrm{3,30}\right]\end{array}\right.---\left(2\right)$

In the shortwave full frequency band, cavity partly is positioned at the near field region of antenna, and remainder is positioned at the far-field region of antenna, then satisfies following relational expression:

$(D+a+d)>\frac{L^2}{50}---\left(3\right)$

Or $(D+a)<\frac{L^2}{5}---\left(4\right)$

When satisfied (3) or (4), then need according to the frequency f that the cavity galvanomagnetic effect occurs ', further judge the place of cavity this moment radiating antenna of living in.

Cavity is positioned at the far field, then satisfies following relational expression:

$D+a>R=\frac{{2L}^2}{\mathrm{\&lambda;}}=\frac{200}{300/f^{\&prime;}}=\frac{2}{3}{f}^{\&prime;}---\left(5\right)$

Cavity partly is positioned at the near field, part is positioned at the far field, then satisfies following relational expression:

$\left\{\begin{array}{c}D+a+d>R\&DoubleRightArrow;D+a+d>\frac{2}{3}{f}^{\&prime;}\\ D+a<R\&DoubleRightArrow;D+a<\frac{2}{3}{f}^{\&prime;}\end{array}\right.---\left(6\right)$

Cavity is positioned at the near field, then satisfies following relational expression:

$D+a+d<\frac{2}{3}{f}^{\&prime;}---\left(7\right)$

When the cavity of a plurality of scatterers formations is arranged on the boats and ships platform, can be converted to the cavity that two scatterers constitute, judged with this method.

Beneficial effect of the present invention is: 1, near the electromagnetic environment strength cavity body structure that is made of sensitive equipment around the substantial radiation source is estimated; 2, provide reference frame for the design of the design of sensitive equipment Electromgnetic seat and electromagnetic protection.

Description of drawings

Fig. 1 is a process flow diagram of the present invention

Fig. 2 is the cavity body structure synoptic diagram

Fig. 3 is the response curve of the electric field intensity of observation point with the radiating antenna frequency of operation

Embodiment

Fig. 1 is a process flow diagram of the present invention, according to the Ship Design scheme, sets up the boats and ships platform in FEKO software, radiating antenna and two scatterers are arranged on the boats and ships platform, as shown in Figure 2, wherein, first scatterer length a=2.3m, width b=1.96m, height c=6.3m; The spacing d=1.2m of first scatterer and second scatterer.The feedback point coordinate of radiating antenna is (5,0,0), and promptly radiating antenna is to the air line distance D=5m of first scatterer.Radiating antenna length L=10m, emissive power is 2000W.Needing the coordinate of the observation point P of research is (1.2,0.98,6.6).

Suppose to have only first scatterer, utilization FEKO computed in software is analyzed, and obtains the response curve (as reference curve) of the electric field intensity of observation point P with the radiating antenna frequency of operation; Suppose to have first scatterer and second scatterer, utilization FEKO computed in software is analyzed, and obtains the response curve of the electric field intensity of observation point P with the radiating antenna frequency of operation, as shown in Figure 3.Two bar response curves contrast back finds that when having two scatterers, tangible field intensity spike phenomenon occurred, therefore, two scatterers among Fig. 2 have constituted cavity body structure, and the cavity galvanomagnetic effect occurs when the pairing frequency of field intensity spike.

With D, a, d, L difference substitution formula (1), (2), (3) and (4), find

Satisfy formula (3) and (4), illustrate that in the shortwave full frequency band, the part of cavity is positioned at the near field region, another part is positioned at the far-field region.

According to theoretical derivation, need according to the frequency f that the cavity galvanomagnetic effect occurs ', further judge the place of cavity this moment radiating antenna of living in.As shown in Figure 3, occur the frequency f of cavity galvanomagnetic effect '=18MHz, then Because Satisfy formula (7), illustrate that cavity when the cavity galvanomagnetic effect occurring is positioned at the near field region of radiating antenna, electric field intensity is bigger around the cavity.

Claims (3)

1. the method for discrimination of cavity structure periphery electromagnetic environment strength, it is characterized in that: it comprises following step:

1) according to the Ship Design scheme, in commercial electromagnetic field simulation software, set up the boats and ships platform, comprise radiating antenna and scatterer on the boats and ships platform, around two scatterers, appoint and get a bit as observation point;

2) use commercial electromagnetic field simulation software, obtain the response curve of the electric field intensity of observation point with the radiating antenna frequency of operation, if tangible field intensity spike has appearred in response curve, illustrate that then these two scatterers have constituted cavity body structure, and when the pairing frequency of field intensity spike, the cavity galvanomagnetic effect occurs;

3) scatterer of establishing with the radiating antenna close together is first scatterer, the scatterer far away with the radiating antenna distance is second scatterer, obtain spacing d, the out to out L of radiating antenna of radiating antenna to length a, first scatterer and second scatterer of the air line distance D of first scatterer, first scatterer, all length unit is rice;

4) judge for the first time: judge by following formula cavity is positioned at which kind of place of radiating antenna in the shortwave full frequency band scope of radiating antenna work:

A, if

Illustrate that then cavity is in the near field region of radiating antenna;

B, if

Illustrate that then cavity is in the far-field region of radiating antenna;

C, if

Or

Illustrate that then the part of cavity is in the near field region of radiating antenna, another part is in the far-field region of radiating antenna;

5), differentiate the cavity periphery electromagnetic environment strength according to the judged result first time:

If the place that cavity is in is above-mentioned steps a, cavity then is described, and electric field intensity is bigger on every side, finishes to judge; If the place that cavity is in is above-mentioned steps b, cavity then is described, and electric field intensity is less on every side, but the existence still of cavity galvanomagnetic effect finishes to judge; If the place that cavity is in is above-mentioned steps c, then carries out the second time and judge.

6) judge for the second time: according to the frequency f that the cavity galvanomagnetic effect occurs ', judge the place of cavity radiating antenna of living in when the cavity galvanomagnetic effect occurring, f ' unit is MHz:

D, if Then explanation cavity this moment is in the near field region;

E, if

Then explanation cavity this moment is in the far-field region;

F, if

And

Then the part of explanation cavity this moment is in the near field region of radiating antenna, and another part is in the far-field region of radiating antenna;

7), differentiate cavity structure periphery electromagnetic environment strength according to the result who judges for the second time:

If the place that cavity is in is above-mentioned steps d, electric field intensity is bigger around the cavity; If the place that cavity is in is above-mentioned steps e, the less existence of electric field intensity around the cavity but the cavity galvanomagnetic effect remains unchanged; If the place that cavity is in is above-mentioned steps f, electric field intensity is taken second place around the cavity.

2. the method for discrimination of cavity structure periphery electromagnetic environment strength according to claim 1, it is characterized in that: described commercial electromagnetic field simulation software is a FEKO software.

3. the method for discrimination of cavity structure periphery electromagnetic environment strength according to claim 1 and 2 is characterized in that: include two or more scatterers on the described boats and ships platform.

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