Miniaturized ultra-wideband partial discharge measurement antenna

Abstract

The application discloses a kind of miniaturized ultra-wideband partial discharge measurement antennas, including support dielectric matrix, antenna main array and antenna auxiliary array, support dielectric matrix adopts circular table structure, and there is a installation slot hole in the center thereof;The antenna main array includes a fan-shaped connection area, and the two sides of the fan-shaped connection area are provided with tooth-shaped radiation arms with increasing width from top to bottom in sequence, and the fan-shaped connection area is connected with the support dielectric matrix;The antenna auxiliary array is distributed in mirror image symmetry with the structure of the antenna main array, and is connected with the support dielectric matrix in a mirror image symmetry manner along the geometric symmetry line of the antenna main array on the support dielectric matrix.Due to the adoption of multiple gradually changing composite tooth-shaped radiation arm structures, and the design form of conformal installation with the antenna support dielectric matrix, the effects of balancing current, expanding the working bandwidth, controlling the antenna radiation direction and compressing the physical size of the antenna radiation are achieved.The installation size requirement is smaller, and the requirement of hidden and narrow space installation is met.

Description

Technical Field

[0001] This invention relates to the field of partial discharge monitoring technology for gas-insulated switchgear in power systems, specifically a miniaturized ultra-wideband partial discharge measurement antenna. Background Technology

[0002] During operation, gas-insulated combined electrical equipment in power systems can generate partial discharges of varying degrees and forms. The electromagnetic pulses generated by these partial discharges can damage the internal insulation materials of the system, leading to insulation breakdown and causing electrical accidents. Therefore, it is necessary to monitor partial discharge signals within the power system to prevent further damage.

[0003] A commonly used technique in partial discharge monitoring is the ultra-high frequency (UHF) partial discharge sensor, which is also an antenna system operating in the 300MHz~1500MHz frequency band, covering both UHF and L-bands. Among these antennas for partial discharge detection, researchers at the University of Strathclyde in the UK first proposed a highly efficient measurement antenna for partial discharge applications. This antenna is actually a modified pole antenna system with a reflector disk and a top-loaded metal capacitor disk. Design and testing showed that this antenna achieves relatively good reception performance when the size of the top-loaded metal disk is greater than 150mm; however, its performance drops sharply once the size is less than 150mm.

[0004] Another type of antenna commonly used in partial discharge measurement systems is the Archimedean spiral or logarithmic spiral antenna. For example, the spiral UHF partial discharge sensor developed by Toshiba Corporation of Japan uses a standard double-arm Archimedean spiral antenna. The double-arm Archimedean spiral antenna is an ultra-wideband frequency-independent antenna with two arms radiating outwards, exhibiting good radiation performance due to a 180-degree phase difference. However, the standard Archimedean spiral antenna, when operating in the UHF band, has a relatively large physical size, making it unsuitable for miniaturized installations. Another type is the partial discharge detection antenna designed using fractal technology, such as the Hilbert fractal antenna proposed by Wang Yongqiang and Wang Zhuang's team. This antenna uses a Hilbert fractal curve of order 4 or higher to construct the radiating arms, and through iterative optimization of the feed position, forms a detection system that can resonate in both the UHF and L-bands. Due to the complex characteristics of fractals, the antenna radiating arms are difficult to fabricate individually, and are generally etched onto a PCB board. However, the strong surface discharge phenomenon on the epoxy glass cloth PCB surface limits the application range of this antenna.

[0005] In addition, in some partial discharge detection systems, in addition to meeting the requirements of high-efficiency antenna reception and wide-band operation, it is also necessary to meet the characteristics of embedded, space-constrained, and miniaturized. The design of new miniaturized, ultra-wideband, and especially space-constrained partial discharge measurement antennas with high gain is becoming increasingly important. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a miniaturized ultra-wideband partial discharge measurement antenna. The antenna radiating element is made of a brass plate of a certain thickness and manufactured according to a design. The antenna and 50-ohm RF cable feed ports are designed using a forward and reverse balanced feeding principle. By optimizing the antenna element structure and feed port dimensions, the requirements for simple direct connection and wide-band operation between the antenna and 50-ohm RF cable in the 300MHz~1500MHz frequency band are met, solving the problem that existing technologies cannot meet the space constraints and miniaturized installation requirements of partial discharge systems.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a miniaturized ultra-wideband partial discharge measurement antenna, comprising:

[0008] The supporting medium substrate adopts a frustum structure, and there is a mounting slot through the center of the frustum.

[0009] The main antenna array includes a fan-shaped connecting area, with toothed radiating arms of progressively increasing width on both sides of the fan-shaped connecting area from top to bottom, and the fan-shaped connecting area is connected to the supporting medium substrate.

[0010] Antenna subarray, wherein the antenna subarray is symmetrically distributed with respect to the main antenna array and is connected to the supporting medium substrate;

[0011] A reflective chassis is mounted on the bottom of a supporting medium substrate, and an radio frequency connector is located on the bottom surface of the reflective chassis.

[0012] The feed cable has its top end passing through the mounting slot and connecting to the main antenna array and the sub-antenna array respectively, and its bottom end connecting to the radio frequency connector at the bottom of the reflector chassis.

[0013] Further defined, the toothed radial arm is composed of a fan-shaped ring with the same center as the fan-shaped region. The central angles of the corresponding fan-shaped rings in the toothed radial arm are the same. The starting segment of the fan-shaped ring is connected to the fan-shaped region, and the tail segment is connected to an extended radial arm. The extended radial arm is also composed of a fan-shaped ring with the same center as the fan-shaped region. The toothed radial arms are arranged alternately from the head to the tail on both sides of the fan-shaped region according to the rule of changing from short to long.

[0014] Further specified, the angle of the fan-shaped connecting area is 45 degrees, and the top and bottom of the fan-shaped connecting area are respectively flush with the top and bottom of the supporting medium substrate and are installed by conformal tangency, application, and adhesive fastening.

[0015] Further specified, the supporting medium substrate is machined from nylon material, and the supporting medium substrate consists of two parts: an upper end and a lower end;

[0016] The upper part is divided into a frustum, with the ratio of the diameter at the top d1 to the diameter at the bottom d2 being 14.8; the lower part is divided into a cylinder, with the ratio of the diameter at the top d2 to the height at the bottom h1 being 47.

[0017] Further specified, the reflective chassis is a metal disc with the same thickness and diameter as the cylinder, and a through hole is opened in the center of the reflective chassis for the power supply connection cable to pass through, and the radio frequency connector is installed in the through hole by screws.

[0018] Furthermore, the bottom surface of the reflective chassis has four mounting holes axially distributed at equal intervals, and the reflective chassis is attached to the cylinder and installed by screws.

[0019] Further specified, the power supply connection cable adopts a 50-ohm coaxial power supply cable, the exposed length of the outer conductor layer stripped at the top of the power supply connection cable is d3, where d2 / d3=6.26, the exposed length of the middle dielectric layer is higher than the length of the outer conductor layer, and the exposed length of the center conductor is d4, where d2 / d4=18.8.

[0020] Further specified, a portion of the exposed central conductor at the top of the feed connection cable is bent at a 90-degree angle toward the side fixed to the top of the main array element, and is firmly soldered to the top of the antenna main array element.

[0021] Another part of the center conductor is bent at a 90-degree angle toward the top of the antenna subarray and soldered firmly to the top of the subarray.

[0022] Furthermore, the radio frequency connector is the commercially available SMA-KFB3A radio frequency connector.

[0023] This invention offers the following advantages: By employing a multi-layered, gradually deformed composite toothed radiating arm structure and a conformal mounting design with the antenna support substrate, it effectively balances current, expands the operating bandwidth, controls the antenna radiation direction, and compresses the physical dimensions of the antenna radiation. The installation size requirements are small, meeting the requirements for concealed installation in confined spaces. Through this design, the antenna meets the vertical polarization and radiation requirements in the UHF and L operating frequency bands, with a maximum antenna gain of not less than 5dB (1.5GHz), and a bandwidth with a VSWR ≤3 accounting for approximately 43% of the entire detection frequency band. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention.

[0025] Figure 2 This is a side view of the present invention.

[0026] Figure 3 This is a top view of the present invention.

[0027] Figure 4 This is a structural diagram of the supporting medium substrate of the present invention.

[0028] Figure 5 This is a structural diagram of the reflector assembly of the present invention.

[0029] Figure 6 This is a diagram of the return loss (S11 parameter) of the present invention.

[0030] Figure 7 This is the E-plane orientation pattern of the present invention.

[0031] Figure 8 This is the H-plane orientation pattern of the present invention.

[0032] In the diagram: 1. Antenna main array; 2. Antenna sub-array; 3. Supporting dielectric substrate; 4. Reflector chassis; 5. Feed connection cable; 6. RF connector. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] See Figure 1-8 This application achieves an antenna scheme that meets the requirements for standing wave ratio and radiation pattern by continuously optimizing and adjusting the overall height of the antenna array, the angle of the sector connection area, the dimensions of each toothed radiating arm and the extended radiating arm. The specific implementation method is as follows:

[0035] like Figure 1-3The main antenna array 1 is made of copper foil of a certain thickness. Its shape consists of a fan-shaped connecting area and multiple deformed toothed radiating arms. Each deformed toothed radiating arm is composed of a fan-shaped ring concentric with the fan-shaped area. The starting segment of the fan-shaped ring connects to the fan-shaped area, and the tail segment connects to an extended radiating arm, which is also composed of a fan-shaped ring concentric with the fan-shaped area. The deformed toothed radiating arms are arranged alternately from the head to the tail of the fan-shaped area, following a rule of increasing length, and are distributed on both sides of the fan-shaped area. The corresponding angle of the fan-shaped connecting area is 45°, and the radius of the fan-shaped area is 68mm. The fan-shaped ring corresponding to each deformed toothed radiating arm has the same angle, which is 56°. The width of the fan-shaped ring corresponding to the deformed toothed radiating arm is determined by the two radii of the concentric circle of the fan-shaped connecting area in the array, where the ratio of the outer ring radius to the inner ring radius is 0.607. The ratio of the outer ring radius of the larger toothed radiating arm's fan-shaped ring to the outer ring radius of the adjacent smaller toothed radiating arms on the same side of the fan-shaped connecting area is 0.55. The angle corresponding to the length of the fan-shaped ring of each deformed toothed radiating arm and its corresponding extended radiating arm is 25°. The ratio of the width of the fan-shaped ring to the outer ring radius should satisfy 0.93. The top and bottom of the fan-shaped connecting area in the main array are flush with, conformally tangent to, the top and bottom of the supporting medium substrate 3, respectively, and are then adhered, glued, and securely installed. The antenna subarray 2 is symmetrically distributed around the center of the antenna main array 1 and is secured in the same manner as the main array.

[0036] like Figure 4 The support medium substrate 3 is machined from nylon. It consists of two parts: the upper part is a frustum with a top diameter of 6.2mm and a bottom diameter of 91mm, connected to a lower part a cylinder with a diameter of 91mm and a height of 1.9mm. A 3.7mm diameter through hole runs from the top of the upper frustum to the bottom of the lower cylinder, serving as a mounting slot for fixing the cable and preventing displacement of the power supply cable 5.

[0037] like Figure 5The reflector base 4 is a 91mm diameter, 2mm thick metal disc made of aluminum. The reflector base 4 is mounted flush against the lower cylindrical surface of the support medium substrate 3. At a radius of 30mm from the center of the metal disc, four 3.2mm diameter through holes are evenly spaced around the axis of the metal disc's thickness. These holes are used for fixed connection to the support medium substrate 3 and are secured with M3×5mm screws. At the center of the reflector base 4, there is a 4mm diameter through hole for the feed cable 5. Around this through hole, with the center of the reflector base 4 as the center, four 2.4mm diameter through holes are evenly spaced around the through hole, around the axis of the disc's thickness, for mounting RF connectors 6.

[0038] The feed cable 5 is a standard 50-ohm coaxial feed cable that meets the installation requirements of the SMA-KFB3A series connectors. The feed cable 5 passes through the mounting slot in the supporting dielectric substrate 3. At the top of the feed cable 5, the outer conductor layer, intermediate dielectric layer, and center conductor must be peeled off layer by layer, leaving an 11mm exposed length for connection to the antenna connector. The exposed length of the intermediate dielectric layer should be 1mm higher than the outer conductor layer, and the exposed length of the center conductor should be 5.5mm. The exposed center conductor should be bent at a 90-degree angle towards the top of the antenna main array 1 without damaging the exposed intermediate dielectric layer, and then soldered securely to the top of the antenna main array 1. A separate section of the same type of coaxial cable as the antenna feed cable is stripped to form a reverse balanced connection line. This stripped section is 16mm long and bent at a 90-degree angle towards the top of the antenna sub-array 2, 11mm above one end. The bent portion is 5.5mm long and soldered securely to the top of the antenna sub-array 22. The 11mm portion is uniformly soldered to the exposed outer conductor layer of the antenna feed cable 5, ensuring that the bent portion is in the same plane as the exposed and bent center conductor portion of the antenna feed cable, and the bending direction is opposite. The bottom end of the feed cable 5 is fixedly connected to the RF connector 6 to ensure the system's 50-ohm electrical connection characteristics.

[0039] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A miniaturized ultra-wideband partial discharge measurement antenna, characterized in that include: The supporting medium substrate adopts a frustum structure, and there is a mounting slot through the center of the frustum. The main antenna array includes a fan-shaped connecting area, with toothed radiating arms of progressively increasing width on both sides of the fan-shaped connecting area from top to bottom, and the fan-shaped connecting area is connected to the supporting medium substrate. Antenna subarray, wherein the antenna subarray is symmetrically distributed with respect to the main antenna array and is connected to the supporting medium substrate; A reflective chassis is mounted on the bottom of a supporting medium substrate, and an radio frequency connector is located on the bottom surface of the reflective chassis. The feed connection cable has its top end passing through the mounting slot and connecting to the main antenna array and the sub-antenna array respectively, and its bottom end connecting to the radio frequency connector at the bottom of the reflector chassis. The toothed radiating arm is composed of a fan-shaped ring concentric with the fan-shaped region. The central angles of the corresponding fan-shaped rings in the toothed radiating arm are the same. The starting segment of the fan-shaped ring is connected to the fan-shaped region, and the tail segment is connected to an extended radiating arm. The extended radiating arm is also composed of a fan-shaped ring concentric with the fan-shaped region. The toothed radiating arms are arranged alternately from the head to the tail on both sides of the fan-shaped region, following a rule of increasing length. The extended radiating arm of the main antenna array is extended to overlap with the toothed radiating arm of the sub-antenna array in the radial direction, and a gap is left between the extended radiating arm of the main antenna array and the sub-antenna array. The extended radiating arm of the sub-antenna array is extended to overlap with the toothed radiating arm of the main antenna array in the radial direction, and a gap is left between the extended radiating arm of the sub-antenna array and the main antenna array. The angle of the fan-shaped connection area is 45 degrees, and the top and bottom of the fan-shaped connection area are flush with the top and bottom of the supporting medium substrate, respectively, and are installed by conformal tangency, pasting, and adhesive fastening. The power supply connection cable adopts a 50-ohm coaxial power supply cable. The exposed length of the outer conductor layer stripped at the top of the power supply connection cable is d3, where d2 / d3=6.

26. The exposed length of the middle dielectric layer is longer than the length of the outer conductor layer. The exposed length of the center conductor is d4, where d2 / d4=18.

8. The exposed portion of the center conductor at the top of the feed connection cable is bent at a 90-degree angle toward the side fixed to the top of the main array and soldered firmly to the top of the antenna main array. Another part of the center conductor is bent at a 90-degree angle toward the top of the antenna subarray and soldered firmly to the top of the subarray.

2. The miniaturized ultra-wideband partial discharge measurement antenna according to claim 1, characterized in that: The supporting medium substrate is machined from nylon material and consists of two parts: an upper end and a lower end. The upper part is divided into a frustum, with the ratio of the diameter at the top d1 to the diameter at the bottom d2 being 14.8; the lower part is divided into a cylinder, with the ratio of the diameter at the top d2 to the height at the bottom h1 being 47.

3. The miniaturized ultra-wideband partial discharge measurement antenna according to claim 2, characterized in that: The reflective chassis is a metal disc with the same thickness and diameter as the cylinder. A through hole is provided in the center of the reflective chassis for the power supply connection cable to pass through. The radio frequency connector is installed in the through hole by screws.

4. The miniaturized ultra-wideband partial discharge measurement antenna according to claim 3, characterized in that: The bottom surface of the reflective chassis has four mounting holes equidistantly distributed axially. The reflective chassis is attached to the cylinder and installed by screws.

5. A miniaturized ultra-wideband partial discharge measurement antenna according to claim 1, characterized in that: The aforementioned RF connector is the commercially available SMA-KFB3A RF connector.

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