Antenna for use with lightning detection sensor

Abstract

A lightning detection sensor is described herein. The lightning sensor includes a sensing element that detects radio frequency (RF) signals associated with lightning activity, a circuit that receives the detected RF signals from the sensing element and amplifies the RF signals for output to a digital signal processing device, and a reference element coupled to the circuit. The reference element is connected to an antenna ground that is isolated from a power supply ground, and the reference element and the antenna ground are not connected to an external ground plane.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 870,248, filed July 3, 2019, which is incorporated herein by reference in its entirety. Technical Field

[0003] This application generally relates to systems and apparatus for lightning detection, including antennas used in conjunction with lightning detection sensors. Background Technology

[0004] The signal generated by lightning is broadband (e.g., 0 Hz–1 GHz), with most of the power concentrated in the lower frequency band. The signal is very strong at low frequencies, therefore, the antennas used in lightning detection sensors typically do not need to be very efficient. Generally, current lightning detection sensor technology often uses monopole electric field variation antennas, where the voltage output is proportional to the electric field convolved with an exponentially decaying field.

[0005] However, this type of antenna requires a stable ground plane and a separate grounding cable. In some geographical areas (e.g., remote or underdeveloped regions with insufficient power infrastructure), it can be difficult to find a stable ground plane and install a grounding cable. Furthermore, over time, the grounding cable is susceptible to corrosion, breakage, and other deterioration, which can cause the lightning detection sensor to malfunction. Continuously monitoring the integrity of the sensor and grounding cable and regularly repairing or replacing the grounding cable is often challenging and expensive. Summary of the Invention

[0006] Therefore, there is a need for an improved antenna design for lightning detection sensors that overcomes the aforementioned obstacles by eliminating the need for a separate grounding cable. The antenna embodiments described herein utilize a center-fed dipole design, which offers the advantage of eliminating the need to connect a grounding cable to the lightning detection sensor and lay it to the ground plane, thereby improving the efficiency and cost associated with sensor installation and maintenance, especially in areas where electrical codes are not well established (or enforced) or where the sensor is powered by a generator. Furthermore, the antenna design embodiments described herein advantageously minimize water bridging or corrosion by providing a sensor body made of a waterproof plastic material (e.g., thermoplastics such as polycarbonate, polyvinyl chloride (PVC), etc.) and incorporating an asymmetric electrode design (one electrode positioned on the outer surface of the sensor body, and the other electrode housed or embedded within the sensor body).

[0007] In one aspect, the invention features a lightning detection sensor. The sensor includes: a sensing element that detects radio frequency (RF) signals associated with lightning activity; circuitry that receives the detected RF signals from the sensing element and amplifies the RF signals for output to a digital signal processing device; and a reference element coupled to the circuitry. The reference element is connected to an antenna ground, which is isolated from a power supply ground, and neither the reference element nor the antenna ground is connected to an external ground plane.

[0008] In some embodiments, the sensing element and the reference element are composed of a conductive metal. In some embodiments, the conductive metal is an aluminum alloy.

[0009] In some embodiments, the lightning detection sensor includes a sensor body that houses one or more of a sensing element, circuitry, or a reference element. In some embodiments, the sensor body is made of a plastic material. In some embodiments, the plastic material is polycarbonate or polyvinyl chloride (PVC). In some embodiments, the sensor body is cylindrical. In some embodiments, circuitry is embedded in the sensor body. In some embodiments, at least a portion of the sensing element is positioned on the outer surface of the sensor body, and at least a portion of the reference element is embedded in the sensor body. In some embodiments, at least a portion of the sensing element is embedded in the sensor body, and at least a portion of the reference element is positioned on the outer surface of the sensor body. In some embodiments, an antenna is grounded to a grounding element located within the sensor body.

[0010] In some embodiments, the gain of the circuit is fixed and calibrated. In some embodiments, a DC-DC converter is used to isolate the antenna ground from the power supply ground. In some embodiments, the circuit includes a reverse charge amplifier that amplifies the RF signal. In some embodiments, the reverse charge amplifier is a fully differential amplifier.

[0011] In some embodiments, the sensor is fixed to a mounting bracket that secures the sensor to a physical structure. In some embodiments, the circuitry is connected to a remote network via a network port coupled to the circuitry.

[0012] Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate the principles of the invention by way of example only. Attached Figure Description

[0013] The advantages and further advantages of the invention described above can be better understood by referring to the following description taken in conjunction with the accompanying drawings. The drawings are not necessarily to scale; rather, the focus is generally placed on illustrating the principles of the invention.

[0014] Figure 1 This is a diagram of an antenna circuit design according to an embodiment of the present invention.

[0015] Figure 2 This is a diagram of another antenna circuit design according to an embodiment of the present invention.

[0016] Figure 3 This is a diagram of a lightning detection sensor according to an embodiment of the present invention.

[0017] Figure 4A This is an exploded view of another lightning detection sensor according to an embodiment of the present invention.

[0018] Figure 4B yes Figure 4A An assembly diagram of a lightning detection sensor. Detailed Implementation

[0019] Figure 1 This is a diagram of an antenna circuit design 100 according to an embodiment of the present invention. Figure 1 As shown, the antenna circuit design 100 includes a center-fed dipole design with a sensing element 102, a reference element 104, an amplifier 106, a capacitor 108, an antenna ground 110, a power ground 112, a DC-DC converter 114, a power source 116, and a signal output 118. The sensing element 102 may include a device (e.g., a whip antenna, an electrode, or a similar device) that detects RF signals generated by lightning activity in the atmosphere, such as cloud-to-ground (CG) lightning strikes and intracloud (IC) pulses. The sensing element 102 transmits the detected RF signal to the amplifier 106-capacitor 108 pair via an optional 100-ohm resistor. In some embodiments, the amplifier 106 is an inverting charge amplifier; however, it should be understood that other types, models, and / or configurations of amplifiers are possible. The amplifier 106 is coupled to the reference element 104, which in some embodiments is a whip antenna, an electrode, or a similar device. In some embodiments, such as Figure 1 In the illustrated embodiment, reference element 104 is coupled to antenna ground 110 and DC-DC converter 114. It is understood that the antenna includes reference element 104 because the electric field change must be measured relative to a reference. Typical monopole designs use an external ground connection. Because there is no external ground connection in the current antenna circuit design 100, reference element 104 is required. It should be understood that in some embodiments, antenna ground 110 is not attached to anything. However, the circuit still requires a local ground to operate. In some antenna configurations, reference element 104 may be attached to antenna ground (e.g., ...). Figure 1 As shown), however, when using differential input, reference element 104 does not need to be attached to antenna ground (as shown). Figure 2 (As shown).

[0020] To allow the antenna to operate without a stable ground, the antenna ground 110 should be isolated from the power source 116 (e.g., the power supply ground 112 of the DSP board supplying power) by using a DC-DC converter 114. Typically, the DC-DC converter includes an oscillator that typically oscillates within the antenna's frequency band. Therefore, careful selection of a converter with particularly low noise and careful filtering of the power supply are necessary. One advantage of doing so is that it allows the use of a dual-supply op-amp and eliminates any bias on the antenna. An exemplary DC-DC converter 114 is CC3-0505SF-E, available from TDK Lambda Corporation.

[0021] Amplifier 106 is further coupled to signal output 118, which provides the detected RF signal to, for example, a DSP board (not shown) to analyze and process the RF signal into a digital waveform representing the detected lightning activity. It should be understood that in some embodiments, the signal level may be slightly lower than that of lightning detection sensors utilizing other types of sensing elements (e.g., signal board designs) because the antenna gain is based on the effective area of ​​sensing element 102. To compensate, the gain of the active circuitry system in the sensor can be adjusted, for example, by reducing the C value (and adjusting R to match) or by using a follower with gain after the charge amplifier. Since the distance between reference element 104 and sensing element 102 is fixed, passive gain is generally less location-dependent. This contrasts with monopole antenna designs, where the distance between the sensing element and external ground depends on how the antenna is mounted. In some embodiments, the antenna gain is fixed and calibrated before the sensor is mounted, which advantageously eliminates any gain variation or attenuation that may be caused by the physical location of the lightning detection sensor (e.g., the height at which the sensor is mounted) and therefore does not require a robust antenna ground.

[0022] Figure 2 This is a diagram of another antenna circuit design 200 according to an embodiment of the present invention. Figure 2 Many of the components shown are similar to those described above. Figure 1 The components are the same, including sensing element 102, reference element 104, capacitor 108, antenna ground 110, power ground 112, DC-DC converter 114, power source 116, and signal output 118. However, as... Figure 2As shown, amplifier 202 includes a fully differential amplifier (such as the AD8274 precision differential amplifier available from Analog Devices of Norwood, Massachusetts). It is understood that the use of a fully differential amplifier provides several advantages, including lower distortion and improved gain accuracy.

[0023] Figure 3 This is a diagram of a lightning detection sensor design 300 according to an embodiment of the present invention. Figure 3 As shown, circuit 100 (e.g., a printed circuit board (PCB)) is encapsulated within a plastic housing 302 and coupled to sensing element 102 and reference element 104. For example, sensing element 102 and reference element 104 are whip antennas attached to the plastic housing 302 via screw plates electrically connected to circuit 100 via wires. The plastic housing 302 is connected to a mounting bracket 304, which can be fixed to a tower, building, or other type of structure. A signal path 306 travels via the mounting bracket 304 from circuit 100 to, for example, a DSP board or other module (not shown) that receives and processes signals from circuit 100. It should be understood that in some embodiments, the DSP board may be embedded within the plastic housing 302.

[0024] Figure 4A and Figure 4B This is a diagram of another lightning detection sensor design 400 according to an embodiment of the present invention. Figure 4A An exploded view of sensor design 400 is provided, showing the separated components, while Figure 4B A view of the same sensor design 400 with fully assembled components is provided. (See attached image.) Figure 4A As shown, the sensor body 402 has a cylindrical shape and may be composed of a waterproof plastic material (such as polycarbonate or polyvinyl chloride (PVC)). It should be understood that other types of plastics and / or waterproof materials may be used without departing from the scope of the invention.

[0025] The circuit 100 (e.g., a PCB) is configured as a circle with a diameter slightly smaller than the diameter of the sensor body 402, such that the circuit 100 can be embedded within the sensor body 402 when the sensor is fully constructed. In some embodiments, the circuit 100 may be mounted on a substrate (not shown) to provide stability and protection for the circuit 100. The circuit 100 and / or the substrate may be secured to the sensing element 102 using, for example, an L-shaped bracket 404 and screws. The L-shaped bracket 404 and screws provide a connection between the sensing element 102 and the circuit 100. The sensing element 102 is positioned on top of the sensor body 402 and is configured with a diameter slightly larger than the diameter of the sensor body, allowing the sensing element 102 to slide downwards over the sensor body 402 such that at least a portion of the sensing element 102 contacts the outer surface of the sensor body 402. The sensing element 102 is composed of a conductive metal, such as 1100 aluminum alloy (although other types of conductive metals may be used within the scope of this invention). Once the sensing element has slid over the sensor body 402, the sensing element 102 can be secured to the sensor body 402 using, for example, a steel screw 406.

[0026] A reference element 104 is positioned at the bottom of the sensor body 402 and is configured to have a diameter slightly smaller than the diameter of the sensor body. This allows the reference element 104 to slide into the sensor body 402, such that at least a portion of the reference element 104 is embedded within the sensor body and contacts the inner surface of the sensor body. The reference element 104 is made of a conductive metal, such as 1100 aluminum alloy (although other types of conductive metals can be used within the scope of this invention). Once the reference element is at least partially embedded in the sensor body 402, it can be secured to the sensor body 402 using, for example, steel screws 408. Furthermore, although... Figure 4A and Figure 4B Not shown, but wires are connected from reference element 104 to circuit 100 to provide a reference signal to circuit 100.

[0027] It should be understood that Figure 4A and Figure 4B The configuration shown is exemplary, and other configurations of the components are conceivable. For example, in some embodiments, the sensing element 102 may be at least partially embedded within the sensor body 402, while the reference element may be at least partially positioned on the outer surface of the sensor body 402. In other embodiments, both the sensing element 102 and the reference element 104 may be at least partially embedded within the sensor body 402. In still other embodiments, both the sensing element 102 and the reference element 104 may be at least partially positioned on the outer surface of the sensor body 402, although in the latter two configurations, the risk of water bridging or moisture penetration inside the sensor increases.

[0028] The sensor body 402 is further connected to a mounting rod 410 that secures the sensor in place. It is understood that the sensor can be attached to another physical object (e.g., a building, tower, or other type of structure) via the mounting rod 410 for the purpose of detecting lightning activity. In some embodiments, cables or wiring may be laid inside the mounting rod to access the interior of the sensor body 402 for coupling to circuitry 100, for example, to carry power up to the antenna and carry signals down from the antenna. In one embodiment, an Ethernet cable may be used, but it should be understood that other types of cable, including simple cabling, may also be used for this purpose. In some embodiments, circuitry 100 may include a network port for engaging with the cable. This configuration enables circuitry 100 to connect to a network to transmit lightning signal data to, for example, a remote computing device. In other embodiments, fiber optic cables may be used to transmit signals from the antenna to an external device.

[0029] As mentioned above, Figure 1 and Figure 2 Antenna circuit design and Figure 3 , Figure 4A and Figure 4B A key advantage of this lightning sensor design is the elimination of a separate external grounding connection to the circuitry. Instead, it utilizes an antenna ground 110 housed within the lightning detection sensor itself. This offers the advantage of eliminating the need for a separate grounding cable to be connected to the lightning detection sensor and laid to the ground plane, thereby improving the efficiency and cost associated with sensor installation and maintenance.

[0030] It should be understood that the embodiments of the invention presented herein are exemplary, and other configurations of the lightning detection sensor element described herein are contemplated within the scope of the described art. The terms "comprise," "include," and / or their plural forms are open-ended and include the listed portions, and may include additional, alternative, and / or substitute portions not listed. They are also open-ended and include one or more of the listed portions and combinations thereof.

[0031] Those skilled in the art will recognize that the present invention can be embodied in other specific forms without departing from the spirit and essential characteristics of the invention. Therefore, the foregoing embodiments are to be regarded in all respects as illustrative rather than limiting of the invention described herein.

Claims

1. A lightning detection sensor, comprising: A sensing element that detects radio frequency (RF) signals associated with lightning activity. A circuit that receives the detected RF signal from the sensing element and amplifies the RF signal for output to a digital signal processing device. A reference element, the reference element being coupled to the circuit, and A sensor body that houses the circuitry and the reference element; The reference element is connected to the antenna ground, and the antenna ground is isolated from the power supply ground. The reference element and the antenna ground are not connected to an external ground plane, and The sensor body and the reference element are not in contact with the ground.

2. The lightning detection sensor as described in claim 1, characterized in that, The sensing element and the reference element are composed of conductive metal.

3. The lightning detection sensor as described in claim 2, characterized in that, The conductive metal is an aluminum alloy.

4. The lightning detection sensor as described in claim 1, characterized in that, The sensor body is made of plastic material.

5. The lightning detection sensor as described in claim 4, characterized in that, The plastic material is polycarbonate or polyvinyl chloride (PVC).

6. The lightning detection sensor as described in claim 1, characterized in that, The sensor body is cylindrical.

7. The lightning detection sensor as described in claim 6, characterized in that, The circuit is embedded in the sensor body.

8. The lightning detection sensor as described in claim 7, characterized in that, At least a portion of the sensing element is positioned on the outer surface of the sensor body, and at least a portion of the reference element is embedded in the sensor body.

9. The lightning detection sensor as described in claim 7, characterized in that, At least a portion of the sensing element is embedded in the sensor body, and at least a portion of the reference element is positioned on the outer surface of the sensor body.

10. The lightning detection sensor as described in claim 1, characterized in that, The antenna is grounded and connected to a grounding element, which is located within the sensor body.

11. The lightning detection sensor as described in claim 1, characterized in that, The gain of the circuit is fixed and calibrated.

12. The lightning detection sensor as described in claim 1, characterized in that, Use a DC-DC converter to isolate the antenna ground from the power supply ground.

13. The lightning detection sensor as described in claim 1, characterized in that, The circuit includes a reverse charge amplifier that amplifies the RF signal.

14. The lightning detection sensor as described in claim 13, characterized in that, The reverse charge amplifier is a fully differential amplifier.

15. The lightning detection sensor as described in claim 1, characterized in that, The sensor is fixed to the mounting bracket, which in turn fixes the sensor to the physical structure.

16. The lightning detection sensor as described in claim 1, characterized in that, The circuit is connected to a remote network via a network port coupled to the circuit.

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