Hall-effect based free-space microwave power detector

Abstract

The present invention discloses a free-space microwave power detector based on the Hall effect. The detector includes a detection component, which is based on the Hall principle and detects through a Hall element. The detected voltage is proportional to the power density of the space electromagnetic wave where the Hall element is located and is independent of the space electromagnetic wave frequency. The detector includes one detection component, and the detection component includes a Hall element, which is placed in an orthogonal electromagnetic field in free space; metal coatings are provided on both sides of the Hall element; metal leads are led out from the metal coatings; the electric field in the orthogonal electromagnetic field is parallel to the metal coatings, and the magnetic field in the orthogonal electromagnetic field is perpendicular to the Hall element; the output voltage of the metal leads is proportional to the power density of the space electromagnetic wave where they are located. The detector also has omnidirectionality, and in this case, the detector includes three detection components. The present invention performs free-space microwave measurement based on the Hall principle; has a simple and reasonable structure, has broadband characteristics, and the overall cost is not high.

Description

Technical Field

[0001] The present invention relates to the field of microwave measurement, and has broad application prospects especially in the fields of broadband omnidirectional microwave power density and field strength measurement. Specifically, it relates to a free-space microwave power detector based on the Hall effect. Background Art

[0002] In the field of free-space microwave measurement, the common method is to use an antenna to receive microwave signals, and then a detector is used to detect the signals to obtain a DC signal for measuring the power density and field strength in space. This technical route has two major drawbacks: one is that the antenna has frequency characteristics, and it is very difficult to achieve consistent antenna efficiency within a wide frequency band. Currently, for the broadband probes of field strength meters such as nadar and Semtech in the market, a large amount of loading and debugging processing has been done on the antenna, so the price of the probe is very expensive, more than 100,000 yuan. The other is that the voltage lead wire is also equivalent to a part of the antenna, so high-frequency filtering processing needs to be carried out on the lead wire, which also increases the cost and technical difficulty. Summary of the Invention

[0003] The technical problem to be solved by the present invention is that in the field of free-space microwave measurement, the existing microwave power detection (as Figure 1 shown) uses an antenna to receive microwave signals, and then a detector is used to detect the signals to obtain a DC signal for measuring the power density and field strength in space. The antenna of this technical route has frequency characteristics, and it is very difficult to achieve consistent antenna efficiency within a wide frequency band. Currently, for the broadband probes of field strength meters such as nadar and Semtech in the market, a large amount of loading and debugging processing has been done on the antenna, so the price of the probe is very expensive, more than 100,000 yuan.

[0004] The object of the present invention is to provide a free-space microwave power detector based on the Hall effect. The structure of the present invention uses a Hall element to replace the mode of an antenna plus a detector in the traditional scheme. It can be deduced that in the case of a free-space electromagnetic field, the voltage obtained by the Hall effect is proportional to the power density and is independent of the frequency of the space electromagnetic wave. Therefore, replacing the traditional antenna plus detector scheme with a Hall element not only has a simple structure, but also can obtain a broadband response without loading the antenna, as Figure 2 shown. The structure of the present invention is simple and reasonable, has broadband characteristics, and the overall cost of the detector is not high.

[0005] The present invention is realized through the following technical solutions:

[0006] A free-space microwave power detector based on the Hall effect, the detector includes a detection component, the detection component is based on the Hall principle and is detected by a Hall element, and the detected voltage is proportional to the power density of the space electromagnetic wave where the Hall element is located and is independent of the frequency of the space electromagnetic wave. The structure of the present invention is simple and reasonable, has broadband characteristics, and the overall cost of the detector is not high.

[0007] The working principle is as follows: Based on the existing microwave power detection, an antenna is used to receive microwave signals, and then a detector is used to detect the signals to obtain a DC signal for measuring the power density and field strength in space. The antenna of this technical route has frequency characteristics, and it is difficult to achieve consistent antenna efficiency within a wide frequency band. At present, for the broadband field intensity meters nadar and the broadband probes of Semtech on the market, a large amount of loading and debugging processes have been carried out on the antenna, so the price of the probe is very expensive, more than 100,000 RMB.

[0008] The present invention takes into account that the Hall effect refers to the phenomenon that when a semiconductor is placed in a magnetic field and there is a current passing through, the charge carriers in the conductor are deflected to one side by the Lorentz force, and then a voltage (Hall voltage) is generated. The electric field force induced by the voltage will balance the Lorentz force. The current of the Hall sensor widely used in industry is a fixed value and is used to measure the magnetic field. The present invention applies the Hall effect to the field of space microwave measurement. For the free-space microwave power detector based on the Hall effect, the electric field and magnetic field acting on the semiconductor are provided by its own orthogonal electromagnetic field. The Hall voltage is proportional to the power density of its own orthogonal electromagnetic field, and the Hall voltage is independent of frequency, having an advantage over the current technical route in the broadband detection field and having a wide application prospect.

[0009] The present invention uses a completely new principle to measure microwave power. Specifically, the Hall effect is used to measure microwave power. The Hall voltage is proportional to the power density of its own orthogonal electromagnetic field, and the Hall voltage is independent of frequency. The derivation and verification are as follows:

[0010] The simplified mathematical model of the free-space microwave power detector based on the Hall effect is as follows. As Figure 7 shown, considering a plane electromagnetic wave incident on a semiconductor device, the electric field of the electromagnetic wave is in the x direction, the magnetic field is in the y direction, and the plane electromagnetic wave propagates in the z direction. The size of the semiconductor is much smaller than the wavelength of the electromagnetic wave, and it is approximately considered that the electric field and magnetic field are the same everywhere in the semiconductor. The time-domain expressions are respectively set as:

[0011] E = E o (t)cosωt

[0012] H = H o (t)cosωt

[0013] where ω is the angular frequency of the electromagnetic wave, E0 is the electric field amplitude, and H0 is the magnetic field amplitude. Relative to the microwave frequency, the electric field and magnetic field amplitudes change slowly with time.

[0014] The current density J generated by the electric field near the surface of the semiconductor Hall device is:

[0015] J = σE

[0016] The magnetic induction intensity B inside the semiconductor Hall device is:

[0017] B = μH

[0018] The Hall voltage generated by the Hall effect can be expressed as:

[0019]

[0020] where I is the current flowing through the conductor, B is the magnetic field applied to the conductor, R H is the Hall coefficient of the conductor material, and d is the thickness of the conductor in the magnetic field direction.

[0021] Substituting the above equations into the expression without Hall voltage, we get:

[0022] V H = WμσR H E o (t)H o (t)cos 2 ωt

[0023] where W is the width of the semiconductor Hall device. Further expanding the above equation, we get:

[0024]

[0025] where the DC component is

[0026]

[0027] In the formula, is a constant determined by the Hall device, and P(t) = E o (t)H o (t) is the power density of the incident plane electromagnetic wave. That is, the Hall voltage is proportional to the microwave power and is independent of the frequency.

[0028] As a further preferred solution, the detector includes a detection component, the detection component includes a Hall element, and the Hall element is placed in an orthogonal electromagnetic field in free space; metal coatings are provided on both sides of the Hall element; metal leads are led out from the metal coatings;

[0029] The microwave in the orthogonal electromagnetic field is incident on the Hall element in the forward direction, that is, the electric field in the orthogonal electromagnetic field is parallel to the metal coating, and the magnetic field in the orthogonal electromagnetic field is perpendicular to the Hall element; the output voltage of the metal lead is proportional to the power density of the space electromagnetic wave where it is located.

[0030] As a further preferred solution, the detector includes three detection components, each detection component includes a Hall element, and the Hall element is placed in an orthogonal electromagnetic field in free space; metal coatings are provided on both sides of the Hall element; metal leads are led out from the metal coatings;

[0031] The three detection components are respectively fixed in the xy plane, yz plane and xz plane by non-metallic fixed casings; the three detection components are perpendicular to each other.

[0032] As a further preferred solution, the relationship between the spatial electromagnetic wave power density of the detector and the voltages measured by the three detection components is:

[0033]

[0034] where V Hx , V Hy , V Hz are the voltage components measured by the three detection components respectively; C is a constant determined by the Hall element; η is the free wave impedance.

[0035] As a further preferred solution, the three detection components respectively receive electromagnetic waves in any direction in free space; the detector has omnidirectionality. That is, the detector can receive electromagnetic waves from any direction, and the electromagnetic wave power density can be calculated from the three voltage values measured by the three components.

[0036] As a further preferred solution, the thickness of the metal coating is between 5 microns and 15 microns.

[0037] As a further preferred solution, the metal coating is made of copper.

[0038] As a further preferred solution, the detection component further includes a low-pass filter and an amplifier. The input end of the low-pass filter is connected to the output end of the metal lead, the output end of the low-pass filter is connected to the input end of the amplifier, and the output end of the amplifier is used as the Hall voltage output signal detected by the detector.

[0039] As a further preferred solution, the low-pass filter uses an RC low-pass filter.

[0040] As a further preferred solution, the Hall element is a device with Hall effect. Specifically, the Hall element includes a metal sheet or a semiconductor.

[0041] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0042] 1. The free-space microwave power detector based on the Hall effect of the present invention measures free-space microwaves based on the Hall principle. The detected voltage is proportional to the power density of the space electromagnetic wave where the Hall element is located and is independent of the space electromagnetic wave frequency. The structure of the present invention is simple and reasonable, has broadband characteristics, and the overall cost of the detector is not high.

[0043] 2. The free-space microwave power detector based on the Hall effect of the present invention inputs the voltage signal proportional to the microwave power obtained by the detection component into the low-pass filter through the lead wire to filter out the interference signals on the lead wire. Then, the DC Hall voltage is amplified by the amplifier to amplify the voltage to a size convenient for measurement; subsequently, the corresponding microwave power can be calculated or obtained by looking up a table based on the Hall voltage; this detector is practical, simple, and convenient.

[0044] 3. The free-space microwave power detector based on the Hall effect of the present invention has broadband characteristics. In the second embodiment, since the detection components are respectively placed in the xy, yz, and xz planes, when the detector of the present invention receives electromagnetic waves with the same power from different directions, the power densities calculated by three groups of voltages are not affected by the incident direction of the electromagnetic waves. Therefore, the microwave power detector of the present invention has omnidirectionality. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not limit the embodiments of the present invention. In the drawings:

[0046] Figure 1 is a schematic structural diagram of a traditional free-space microwave detector.

[0047] Figure 2 is a schematic structural diagram of the free-space microwave power detector based on the Hall effect of the present invention.

[0048] Figure 3 is a schematic structural diagram of the free-space microwave power detector based on the Hall effect in Embodiment 1 of the present invention.

[0049] Figure 4 is a schematic structural diagram of the free-space microwave power detector based on the Hall effect in Embodiment 2 of the present invention.

[0050] Figure 5 is a schematic structural diagram of the free-space microwave power detector based on the Hall effect in Embodiment 3 of the present invention Figure 1 .

[0051] Figure 6 is a schematic structural diagram of the free-space microwave power detector based on the Hall effect in Embodiment 3 of the present invention Figure 2 .

[0052] Figure 7 Schematic diagram of the response of a semiconductor device under plane wave incidence conditions.

[0053] Reference numerals and corresponding component names:

[0054] 1 - Hall element, 2 - Metal coating, 3 - Metal lead, 4 - Low - pass filter, 5 - Amplifier, 6 - Non - metallic fixed housing. Detailed implementation manners

[0055] In the following, the term "comprising" or "may comprise" that can be used in various embodiments of the present invention indicates the presence of the functions, operations, or elements of the invention, and does not limit the addition of one or more functions, operations, or elements. In addition, as used in various embodiments of the present invention, the terms "comprising", "having" and their cognates are only intended to indicate specific features, numbers, steps, operations, elements, components, or combinations of the foregoing items, and should not be construed as precluding the existence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing items.

[0056] In various embodiments of the present invention, the expression "or" or "at least one of A or / and B" includes any combination or all combinations of the recited words. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0057] Expressions (such as "first", "second", etc.) used in various embodiments of the present invention may modify various components in various embodiments, but do not limit the corresponding components. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only for the purpose of distinguishing one element from other elements. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of various embodiments of the present invention, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0058] It should be noted that: If it is described that one component is "connected" to another component, the first component may be directly connected to the second component, and a third component may be "connected" between the first component and the second component. On the contrary, when one component is "directly connected" to another component, it can be understood that there is no third component between the first component and the second component.

[0059] The terms used in various embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the various embodiments of the present invention. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the present invention pertain. The terms (such as those defined in a general-use dictionary) will be interpreted to have the same meaning as the contextual meaning in the relevant technical field and will not be interpreted to have an idealized meaning or an overly formal meaning, unless clearly defined in the various embodiments of the present invention.

[0060] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to embodiments and drawings. The illustrative embodiments and descriptions of the present invention are only for explaining the present invention and do not constitute a limitation to the present invention.

[0061] Embodiment 1

[0062] As Figure 3 shown, the free-space microwave power detector of the present invention is based on the Hall effect. The detector includes a detection component, which is based on the Hall principle and detects through a Hall element. The detected voltage is proportional to the power density of the space electromagnetic wave where the Hall element is located and is independent of the space electromagnetic wave frequency. And it has broadband characteristics.

[0063] The present invention applies the Hall effect to the field of space microwave measurement. The free-space microwave power detector based on the Hall effect has its electric field and magnetic field acting on the semiconductor both provided externally. The Hall voltage is proportional to the power density of its own orthogonal electromagnetic field and is independent of frequency. It has advantages over the current technical routes in the broadband detection field and has broad application prospects.

[0064] The free-space microwave power detector of this technical solution performs free-space microwave measurement based on the Hall effect principle. The detected voltage is proportional to the power density of the space electromagnetic wave where the Hall element is located and is independent of the space electromagnetic wave frequency. The structure of the present invention is simple and reasonable, has broadband characteristics, and the overall cost of the detector is not high.

[0065] In specific implementation, this embodiment is implemented with one detection component, and the microwave in the orthogonal electromagnetic field is incident on the Hall element 1 in the forward direction; specifically as follows:

[0066] As Figure 3As shown, the detector includes a detection component, and the detection component includes a Hall element 1, and the Hall element 1 is made of a semiconductor or a metal sheet; the Hall element 1 is placed in an orthogonal electromagnetic field in free space; metal coatings 2 are provided on both sides of the Hall element 1; metal leads 3 are led out from the metal coatings 2;

[0067] The microwave in the orthogonal electromagnetic field is incident on the Hall element 1 in the forward direction, that is, the microwave in the orthogonal electromagnetic field is incident on the Hall element 1 in the forward direction, the electric field in the orthogonal electromagnetic field is parallel to the metal coating 2, and the magnetic field in the orthogonal electromagnetic field is perpendicular to the Hall element 1; the output voltage of the metal lead 3 is proportional to the power density of the space electromagnetic wave where it is located.

[0068] In this embodiment, the thickness of the metal coating 2 is between 5 microns and 15 microns.

[0069] In this embodiment, the metal coating 2 is made of copper.

[0070] The working principle is as follows: The principle of the free-space microwave power detector based on the Hall effect is to consider a plane electromagnetic wave incident on a Hall element (for example, a semiconductor sheet), the electric field of the electromagnetic wave is in the x direction, the magnetic field is in the y direction, and the plane electromagnetic wave propagates in the z direction. The size of the semiconductor sheet is much smaller than the wavelength of the electromagnetic wave, and it is approximately considered that the electric field and magnetic field are the same everywhere in the semiconductor device; through reasoning, it is obtained that the Hall voltage is proportional to the microwave power density or microwave power, and the Hall voltage is independent of frequency.

[0071] Under the action of the magnetic field component B perpendicular to the semiconductor sheet and the electric field E parallel to the metal coating 2 and the semiconductor sheet in the present invention, the free electrons in the semiconductor sheet drift directionally under the action of the Lorentz force, and electrons and positive charges are accumulated on both sides of the metal coating 2 respectively, so a potential difference is formed on both sides of the metal coating 2, that is, a Hall electric field appears, so that the directionally moving electrons are affected by not only the Lorentz magnetic force but also the force of the Hall electric field, and this force prevents the charge from continuing to accumulate. As the charge accumulated on both sides of the metal coating 2 increases, the Hall electric field increases, and the electric field force received by the electrons also increases. When the Lorentz magnetic force received by the electrons is equal in magnitude and opposite in direction to the force of the Hall electric field, an equilibrium state is reached. At this time, the pressure difference on both sides of the metal coating 2 is Vs, and this voltage Vs is proportional to the microwave power density where the semiconductor sheet is located and is independent of frequency, and this voltage Vs is output by the metal lead 3. Therefore, this detector measures the Hall voltage, and subsequently, the corresponding microwave power can be calculated or obtained by looking up a table corresponding to the Hall voltage; this detector is practical, simple and convenient.

[0072] Embodiment 2

[0073] As Figure 4As shown, the difference between this embodiment and Embodiment 1 is that the detection component further includes a low-pass filter 4 and an amplifier 5. The input end of the low-pass filter 4 is connected to the output end of the metal lead 3, the output end of the low-pass filter 4 is connected to the input end of the amplifier 5, and the output end of the amplifier 5 serves as the Hall voltage output signal detected by the detector.

[0074] The low-pass filter 4 is used to receive the induced voltage of the metal lead 3 of the detection component and output a filtered voltage signal to the amplifier 5.

[0075] The amplifier 5 is used to receive the filtered voltage signal and output an amplified Hall voltage signal.

[0076] In this embodiment, the low-pass filter 4 adopts an RC low-pass filter, and the amplifier 5 can adopt an ordinary operational amplifier; and both the low-pass filter 4 and the amplifier 5 are devices of the prior art, so no detailed description will be given here.

[0077] The voltage signal proportional to the microwave power obtained by the detection component of the present invention is input to the low-pass filter through the lead to filter out the interference signal on the lead. Then, the DC Hall voltage is amplified by the amplifier to meet the detection magnitude requirement; subsequently, the corresponding microwave power can be calculated or obtained by looking up a table based on the Hall voltage; this detector is practical, simple, and convenient.

[0078] Embodiment 3

[0079] As Figure 5 , Figure 6 shown, the difference between this embodiment and Embodiment 1 is that this embodiment is implemented with three detection components, and the three detection components respectively receive electromagnetic waves in any direction in free space; the detector has omnidirectionality. That is, the detector can receive electromagnetic waves from any direction, and the electromagnetic wave power density can be calculated from the three voltage values measured by the three components. Specifically as follows:

[0080] As Figure 5 shown, the detector includes three detection components, and the detection component includes a Hall element 1, and the Hall element 1 is placed in an orthogonal electromagnetic field in free space; metal coatings 2 are provided on both sides of the Hall element 1; metal leads 3 are led out from the metal coatings 2.

[0081] The three detection components are respectively fixed in the xy plane, yz plane, and xz plane through a non-metallic fixed housing 6; the three detection components are perpendicular to each other; the induced voltage of the metal lead 3 of each detection component is proportional to the electromagnetic wave power density in the space where it is located.

[0082] Since the direction of the electromagnetic field in space does not propagate in a specific direction, in order to make the detector omnidirectional, the present invention uses three detection components, which are fixed in the xy, yz, and xz planes by non-metallic materials respectively. The relationship between the power density and the voltages measured by these three detection components is as follows: As shown in the formula. V Hx , V Hy , V Hz are the voltage components measured by these three detection components respectively. is a constant determined by semiconductor devices, and η is the free wave impedance. According to the voltage components measured by the three detection components, the microwave power density is calculated by the P formula, and then the microwave power is obtained.

[0083] Therefore, the microwave power detector of the present invention has broadband characteristics. In addition, since the detection components are placed in the xy, yz, and xz planes respectively, these three detection components enable the detector of the present invention to receive electromagnetic waves in any direction. Therefore, the microwave power detector of the present invention has omnidirectionality.

[0084] As Figure 6 shown, on the basis of the above Figure 5 , when implemented with three detection components, the detector further includes a low-pass filter 4 and an amplifier 5. The input end of the low-pass filter 4 is connected to the output ends of the metal leads 3 corresponding to the three detection components, the output end of the low-pass filter 4 is connected to the input end of the amplifier 5, and the output end of the amplifier 5 is used as the output signal of the Hall voltage detected by the detector;

[0085] The low-pass filter 4 is used to receive the induced voltages of the metal leads 3 corresponding to the three detection components and output the filtered voltage signal to the amplifier 5;

[0086] The amplifier 5 is used to receive the filtered voltage signal and output the amplified Hall voltage signal.

[0087] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A free-space microwave power detector based on the Hall effect, characterized in that, The detector includes a detection component, which is based on the Hall principle and detects through a Hall element. The detected voltage is proportional to the power density of the spatial electromagnetic wave where the Hall element is located and is independent of the spatial electromagnetic wave frequency; The detector includes three detection components. The detection component includes a Hall element (1), and the Hall element (1) is placed in an orthogonal electromagnetic field in free space; metal coatings (2) are provided on both sides of the Hall element (1); metal leads (3) are led out from the metal coatings (2); The three detection components are respectively fixed in the xy plane, yz plane, and xz plane through non-metallic fixed casings (6); the three detection components are perpendicular to each other; The relationship between the power density of the spatial electromagnetic wave of the detector and the voltages measured by the three detection components is: Among them, V Hx , V Hy , V Hz are the voltage components measured by three detection components respectively; C is a constant determined by the Hall element; η is the free wave impedance.

2. The free space microwave power detector based on the Hall effect according to claim 1, characterized in that, The three detection components respectively receive electromagnetic waves in any direction in free space; the detector has omnidirectionality.

3. The free space microwave power detector based on the Hall effect according to claim 2, characterized in that, The thickness of the metal coating (2) is between 5 microns and 15 microns.

4. The free space microwave power detector based on the Hall effect according to any one of claims 2 to 3, characterized in that, The metal coating (2) is made of copper.

5. The free space microwave power detector based on the Hall effect according to any one of claims 2 to 3, characterized in that, The detection component further includes a low-pass filter (4) and an amplifier (5). The input end of the low-pass filter (4) is connected to the output end of the metal lead (3), the output end of the low-pass filter (4) is connected to the input end of the amplifier (5), and the output end of the amplifier (5) is used as the Hall voltage output signal detected by the detector.

6. The free space microwave power detector based on the Hall effect according to claim 1, characterized in that, The Hall element (1) is a device with Hall effect.

7. The free space microwave power detector based on the Hall effect according to claim 5, characterized in that, The Hall element (1) includes a metal thin sheet or a semiconductor.

Images