Surface current probe calibration device based on parallel plate bounded waveguide structure

Abstract

The invention provides a surface current probe calibration device based on a parallel plate bounded waveguide structure. The surface current probe calibration device comprises a first transition section, a parallel plate working section and a second transition section which are connected in sequence, the end, not connected with the parallel plate working section, of the first transition section is electrically connected with the vector network analyzer, the end, not connected with the parallel plate working section, of the second transition section is electrically connected with the coaxial load, and the characteristic impedance of the first transition section, the characteristic impedance of the parallel plate working section and the characteristic impedance of the second transition section are all 50 ohms. According to the surface current probe calibration device based on the parallel plate bounded waveguide structure provided by the invention, a large-area and uniformly-distributed surface current is constructed by arranging the parallel plate working section; the characteristic impedance of the working section of the parallel plate is matched with the vector network analyzer, so that the reflection of incident waves is avoided, and the calibration precision is improved; the size of the parallel plate working section is far greater than the width of the surface current probe, so that the influence of the edge effect on the calibration precision is avoided; the working section of the parallel plate is of an open waveguide structure, so that the calibration process is simple to operate.

Description

Technical Field

[0001] The invention relates to the technical field of surface current probe calibration, in particular to a surface current probe calibration device based on a parallel plate bounded waveguide structure. Background Art

[0002] The electromagnetic fields generated by electromagnetic radiation sources such as lightning, electromagnetic pulses, and high-power microwaves interact with the shell of the electronic system, which can produce surface current distribution on the surface of the electronic system. The surface current is cut by the discontinuous structure on the surface of the electronic system, generating secondary radiation inside the system. This electromagnetic coupling effect is an important part of the study of electromagnetic environmental effects.

[0003] The surface current induced on the system surface can be measured by a surface current probe. The surface current probe converts the radiation field of the surface current into a voltage signal through the principle of electromagnetic induction. The amplitude, waveform, distribution and other information of the surface current can be obtained through an oscilloscope. The surface current probe needs to be strictly calibrated before quantitative measurement can be performed. Currently, there is no device on the market for calibrating surface current probes. Summary of the invention

[0004] The object of the present invention is to provide a surface current probe calibration device based on a parallel plate bounded waveguide structure, which can solve one or more of the above-mentioned prior art problems.

[0005] According to one aspect of the present invention, a surface current probe calibration device based on a parallel plate bounded waveguide structure is provided, comprising a first transition section, a parallel plate working section and a second transition section connected in sequence; an end of the first transition section not connected to the parallel plate working section is electrically connected to a vector network analyzer, an end of the second transition section not connected to the parallel plate working section is electrically connected to a coaxial load, the first transition section and the second transition section are both conical structures, the parallel plate working section comprises a first electrode plate and a second electrode plate arranged in parallel, and the characteristic impedances of the first transition section, the parallel plate working section and the second transition section are all 50 ohms.

[0006] In some implementations, the first transition section is connected to the vector network analyzer via an N-type terminal.

[0007] In some embodiments, the second transition section is connected to a coaxial load through an N-type terminal, and the coaxial load is 50 ohms.

[0008] In some embodiments, the first transition section includes a first plate and a second plate, the first plate and the second plate are equal in shape and size, the first plate includes a first vertex and a first side opposite to the first vertex, the second plate includes a second vertex and a second side opposite to the second vertex, the first vertex and the second vertex are connected, and the first side and the second side are respectively connected to the first electrode plate and the second electrode plate; the second transition section includes a third plate and a fourth plate, the third plate and the fourth plate are equal in shape and size, the third plate includes a third vertex and a third side opposite to the third vertex, the fourth plate includes a fourth vertex and a fourth side opposite to the fourth vertex, the third vertex and the fourth vertex are connected, and the third side and the fourth side are respectively connected to the first electrode plate and the second electrode plate.

[0009] In some embodiments, the first flat plate, the second flat plate, the third flat plate and the fourth flat plate are all equilateral triangular metal plates with a side length of 1000 mm.

[0010] In some embodiments, the cone angle formed by one end where the first plate is connected to the second plate is 13°; and the cone angle formed by one end where the third plate is connected to the fourth plate is 13°.

[0011] In some embodiments, the first electrode plate and the second electrode plate are rectangular metal plates of equal size, and the two opposite sides of the first electrode plate are respectively connected to the first transition section and the second transition section, and the side lengths of the two sides of the first electrode plate connected to the first transition section or the second transition section are greater than the side lengths of the two sides of the first electrode plate not connected to the first transition section or the second transition section; the two opposite sides of the second electrode plate are respectively connected to the first transition section and the second transition section, and the side lengths of the two sides of the second electrode plate connected to the first transition section or the second transition section are greater than the side lengths of the two sides of the second electrode plate not connected to the first transition section or the second transition section.

[0012] In some embodiments, the vertical distance between the first electrode plate and the second electrode plate is 0.2 m.

[0013] In some embodiments, the side length of the first electrode plate connected to the first transition section or the second transition section is 1000 mm; the side length of the second electrode plate connected to the first transition section or the second transition section is 1000 mm.

[0014] The surface current probe calibration device based on the parallel plate bounded waveguide structure provided by the present invention constructs a surface current with a large area and uniform distribution based on the electromagnetic wave bounded waveguide transmission principle; the characteristic impedance of the parallel plate bounded waveguide structure can match the vector network analyzer, avoiding the reflection of the incident wave and effectively improving the calibration accuracy; the width of the parallel plate working section, that is, the calibration area, is much larger than the width of the surface current probe, avoiding the influence of the edge effect on the calibration accuracy; the open waveguide structure is adopted, which is easy to place the surface current probe and the calibration process is simple to operate.

[0015] In addition, in the technical solution of the present invention, unless otherwise specified, the technical solution can be implemented by adopting conventional means in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A three-dimensional diagram of a surface current probe calibration device based on a parallel plate bounded waveguide structure provided by one embodiment of the present invention.

[0018] Figure 2 A top view of a surface current probe calibration device based on a parallel plate bounded waveguide structure provided by one embodiment of the present invention.

[0019] Figure 3 A front view of a surface current probe calibration device based on a parallel plate bounded waveguide structure provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example:

[0022] In this embodiment, refer to the attached manual Figure 1-3 A surface current probe calibration device based on a parallel plate bounded waveguide structure is provided, comprising: a first transition section 1, a parallel plate working section 2 and a second transition section 3 connected in sequence, wherein the characteristic impedances of the first transition section 1, the parallel plate working section 2 and the second transition section 3 are all 50 ohms, wherein the parallel plate working section 2 serves as a calibration area.

[0023] One end of the first transition section 1 not connected to the parallel plate working section 2 is used for electrical connection to a vector network analyzer, and one end of the second transition section 3 not connected to the parallel plate working section 2 is used for electrical connection to a coaxial load.

[0024] The first transition section 1 is connected to a vector network analyzer through an N-type terminal, and the second transition section 3 is connected to a 50-ohm coaxial load through an N-type terminal.

[0025] The parallel plate working section 2 includes a first pole plate 21 and a second pole plate 22 arranged in parallel, and the first pole plate 21 and the second pole plate 22 are equal in shape and size. Therefore, the electromagnetic wave propagates in the parallel plate bounded waveguide in the form of a quasi-TEM wave, and generates a uniformly distributed surface current on the first pole plate 21 and the second pole plate 22 of the parallel plate working section 2.

[0026] The first transition section 1 may include a first flat plate 11 and a second flat plate 12. The first flat plate 11 and the second flat plate 12 are equal in shape and size. The first flat plate 11 includes a first vertex and a first side opposite to the first vertex. The second flat plate 12 includes a second vertex and a second side opposite to the second vertex. The first vertex and the second vertex are connected, and the first side and the second side are connected to the first electrode plate 21 and the second electrode plate 22, respectively.

[0027] The second transition section 3 may include a third plate 31 and a fourth plate 32. The third plate 31 and the fourth plate 32 are equal in shape and size. The third plate 31 includes a third vertex and a third side opposite to the third vertex. The fourth plate 32 includes a fourth vertex and a fourth side opposite to the fourth vertex. The third vertex and the fourth vertex are connected, and the third side and the fourth side are connected to the first electrode plate 21 and the second electrode plate 22 respectively.

[0028] The first transition section 1 and the second transition section 3 are both conical structures. Specifically, the first plate 11, the second plate 12, the third plate 31 and the fourth plate 32 can all be equilateral triangular metal plates with the same side length, and the first electrode 21 and the second electrode 22 can be rectangular metal plates of equal size. At this time, the first transition section 1 is a conical structure formed by the first plate 11 and the second plate 12, and the second transition section 3 is a conical structure formed by the third plate 31 and the fourth plate 32. The first transition section 1 and the second transition section 3 are relatively arranged on both sides of the parallel plate working section 2. Specifically, the first plate 11 and the third plate 31 are relatively arranged on both sides of the first electrode 21, and the second plate 12 and the fourth plate 32 are relatively arranged on both sides of the second electrode 22.

[0029] Specifically, the side length of the equilateral triangle may be 1000 mm, the internal angle α of the equilateral triangle may be 60°, and the size of the rectangular metal plate may be 1000 mm×500 mm.

[0030] The cone angle β formed by one end of the first plate 11 connected to the second plate 12 is 13°; the cone angle β formed by one end of the third plate 31 connected to the fourth plate 32 is 13°.

[0031] In an optional embodiment, a vertical distance h between the first electrode plate 21 and the second electrode plate 22 is 0.2 m.

[0032] In an optional embodiment, two opposite sides of the first electrode plate 21 are respectively connected to the first transition section 1 and the second transition section 3, and the length of the two sides of the first electrode plate 21 connected to the first transition section 1 or the second transition section 3 is greater than the length of the two sides of the first electrode plate 21 not connected to the first transition section 1 or the second transition section 3. Two opposite sides of the second electrode plate are respectively connected to the first transition section 1 and the second transition section, and the length of the two sides of the second electrode plate connected to the first transition section 1 or the second transition section is greater than the length of the two sides of the second electrode plate not connected to the first transition section 1 or the second transition section.

[0033] In an optional embodiment, the side length ω of the side of the first electrode 21 connected to the first transition section 1 or the second transition section is 1000 mm, and the side length ω of the side of the second electrode 22 connected to the first transition section 1 or the second transition section is 1000 mm; the side length ω1 of the side of the first electrode 21 not connected to the first transition section 1 or the second transition section is 500 mm, and the side length ω1 of the side of the second electrode 22 not connected to the first transition section 1 or the second transition section is 500 mm;

[0034] The calculation formula of the characteristic impedance of the parallel plate working section 2 is:

[0035]

[0036] In the formula, h / ω≤1, when h=0.2m, ω=1m, Z is calculated c =50Ω, thus, h=0.2m, ω=1m can meet the requirement that the characteristic impedance of the parallel plate working section 2 is 50 ohms.

[0037] Since the structures of the first transition section 1 and the second transition section 3 are non-parallel, the structures of the first transition section 1 and the second transition section 3 are gradually changed. If the first transition section 1 and the second transition section 3 are to maintain 50Ω unchanged, the cone angle β of the first transition section 1 and the second transition section 3 needs to meet the following conditions:

[0038]

[0039] Wherein, α represents the internal angles of the first plate 11, the second plate 12, the third plate 31 and the fourth plate 32, α represents the cone angles of the first transition section 1 and the second transition section 3, when the first plate 11, the second plate 12, the third plate 31 and the fourth plate 32 are all equilateral triangles, α=60°, when h=0.2m, ω=1m, β=13° is calculated.

[0040] The present invention provides a surface current probe calibration device based on a parallel plate bounded waveguide structure. When calibrating the surface current probe, the first transition section 1 is connected to a vector network analyzer through an N-type terminal, the second transition section 3 is connected to a 50Ω coaxial load through an N-type terminal, the parallel plate working section 2 is a parallel plate bounded waveguide structure, the characteristic impedance of the parallel plate working section 2 is 50Ω, and electromagnetic waves propagate in the bounded waveguide structure in the form of quasi-TEM waves, and generate uniformly distributed surface currents on the first pole plate 21 and the second pole plate 22 of the parallel plate working section 2, thereby realizing the calibration of the surface current probe.

[0041] Since the surface current probe must be strictly calibrated before quantitative measurement can be performed, the calibration device of the surface current probe needs to meet the following conditions: the calibration device can produce a surface current distribution with good uniformity, and the amplitude of the surface current can be accurately calculated by the laws of physics; at the same time, since the surface current probe is a broadband measurement tool, its amplitude-frequency characteristics need to be measured using a vector network analyzer, so the calibration device needs to match the impedance of the vector network analyzer.

[0042] The surface current probe calibration device based on the parallel plate bounded waveguide structure provided in the present application can obtain the density of the surface current by calculation. The specific calculation method is as follows:

[0043] Transfer impedance Z of surface current probe t The calculation formula is,

[0044]

[0045] Where V2 represents the measured voltage, I1 represents the current to be measured, V1 represents the voltage applied to the waveguide structure, and Z c Represents the characteristic impedance of the waveguide structure, t=ω0 / ω1, wherein ω1 represents the length of the side of the first electrode 21 or the second electrode 22 that is not connected to the first transition section 1 or the second transition section 3, and ω0 represents the equivalent width of the surface current probe to be calibrated.

[0046] According to the transfer impedance Z of the surface current probe t The calculation formula can be obtained:

[0047] Z tdB =S 21 +Z cdB -20 ligt

[0048] In the formula, Z tdB is the transfer impedance Z t dB indicates that S 21 is the transmission coefficient of the calibrated current probe measured by the vector network analyzer, Z cdB is the characteristic impedance Z c Expressed in dB.

[0049] Since the input impedance of the vector network analyzer is 50Ω, the matching resistance of the surface current probe is approximately equal to 50Ω, and the transfer impedance Z tdB 6dB needs to be added to the right side of the expression.

[0050] In summary, the calculation formula for the surface current density measured by the surface current probe is as follows:

[0051]

[0052] Where, the surface current density J s The unit is A / m.

[0053] The surface current probe calibration device based on the parallel plate bounded waveguide structure provided by the present invention constructs a surface current with a large area and uniform distribution by setting a parallel plate working section 2; the characteristic impedance of the parallel plate working section 2 can match the vector network analyzer, avoiding the reflection of the incident wave and effectively improving the calibration accuracy; the size of the parallel plate working section, that is, the calibration area, is much larger than the width of the surface current probe, avoiding the influence of the edge effect on the calibration accuracy; the parallel plate working section is an open waveguide structure, which is easy to place the surface current probe and the calibration process is simple to operate.

[0054] The above description is only an optional implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A surface current probe calibration device based on a parallel plate bounded waveguide structure, characterized in that: include: A first transition section, a parallel plate working section and a second transition section connected in sequence; One end of the first transition section that is not connected to the parallel plate working section is electrically connected to a vector network analyzer. One end of the second transition section not connected to the parallel plate working section is electrically connected to the coaxial load. The first transition section and the second transition section are both conical structures; The parallel plate working section includes a first electrode plate and a second electrode plate arranged in parallel. The characteristic impedances of the first transition section, the parallel plate working section and the second transition section are all 50 ohms.

2. The surface current probe calibration device based on the parallel plate bounded waveguide structure according to claim 1 is characterized in that: The first transition section is connected to the vector network analyzer through an N-type terminal.

3. The surface current probe calibration device based on the parallel plate bounded waveguide structure according to claim 1, characterized in that: The second transition section is connected to a coaxial load through an N-type terminal, and the coaxial load is 50 ohms.

4. The surface current probe calibration device based on the parallel plate bounded waveguide structure according to claim 1, characterized in that: The first transition section includes a first plate and a second plate, the first plate and the second plate are equal in shape and size, the first plate includes a first vertex and a first side opposite to the first vertex, the second plate includes a second vertex and a second side opposite to the second vertex, the first vertex and the second vertex are connected, and the first side and the second side are connected to the first electrode plate and the second electrode plate respectively; The second transition section includes a third plate and a fourth plate, the third plate and the fourth plate are equal in shape and size, the third plate includes a third vertex and a third side opposite to the third vertex, the fourth plate includes a fourth vertex and a fourth side opposite to the fourth vertex, the third vertex and the fourth vertex are connected, and the third side and the fourth side are respectively connected to the first electrode plate and the second electrode plate.

5. The surface current probe calibration device based on the parallel plate bounded waveguide structure according to claim 4 is characterized in that: The first flat plate, the second flat plate, the third flat plate and the fourth flat plate are all equilateral triangular metal plates with a side length of 1000 mm.

6. The surface current probe calibration device based on the parallel plate bounded waveguide structure according to claim 5, characterized in that: The cone angle formed by one end of the first plate connected to the second plate is 13°; the cone angle formed by one end of the third plate connected to the fourth plate is 13°.

7. The surface current probe calibration device based on the parallel plate bounded waveguide structure according to claim 1, characterized in that: The first electrode plate and the second electrode plate are rectangular metal plates of equal size. Two opposite sides of the first electrode plate are connected to the first transition section and the second transition section respectively, and the lengths of the two sides of the first electrode plate connected to the first transition section or the second transition section are greater than the lengths of the two sides of the first electrode plate not connected to the first transition section or the second transition section; The two opposite sides of the second electrode plate are respectively connected to the first transition section and the second transition section, and the side lengths of the two sides of the second electrode plate connected to the first transition section or the second transition section are greater than the side lengths of the two sides of the second electrode plate not connected to the first transition section or the second transition section.

8. The surface current probe calibration device based on the parallel plate bounded waveguide structure according to claim 1, characterized in that: The vertical distance between the first electrode plate and the second electrode plate is 0.2 m.

9. The surface current probe calibration device based on the parallel plate bounded waveguide structure according to claim 1, characterized in that: The length of the side of the first electrode plate connected to the first transition section or the second transition section is 1000 mm; The length of the side of the second electrode plate connected to the first transition section or the second transition section is 1000 mm.

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