Non-frequency variant elliptical dipole antenna applied to spectrum measurement

Abstract

The application provides a non-frequency conversion elliptical dipole antenna applied to spectrum measurement, which comprises a receiver, an antenna feed structure, an antenna oscillator, an antenna oscillator internal support frame, a folding arm and an antenna support, the antenna oscillator comprises left and right antenna oscillators, and the cavity of the left and right antenna oscillators is internally provided with the antenna oscillator internal support frame; the antenna oscillator internal support frame in the left antenna oscillator is fixed with a box body for placing the receiver; the antenna feed structure is arranged between the left antenna oscillator and the right antenna oscillator; the left antenna oscillator is electrically connected with the shell of a first radio frequency connector in the antenna feed structure, and the right antenna oscillator is electrically connected with the inner core of a second radio frequency connector in the antenna feed structure; and the first radio frequency connector is connected with the receiver through a feed line. The non-frequency conversion elliptical dipole antenna realizes the characteristics of wideband non-frequency conversion, as small antenna pattern color difference as possible, integrated design of the antenna and the receiver, no balun coupling structure and smooth frequency response.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a non-frequency-variable elliptical dipole antenna for spectrum measurement. Background Technology

[0002] During the cosmic dawn and reionization periods, neutral hydrogen atoms generated a 21 cm signal through hyperfine structure transitions. This signal provides an important observational tool for exploring the early evolutionary history of the universe. With the expansion and evolution of the universe, the corresponding 21 cm signal has redshifted to the low-frequency radio band of 50-100 MHz. Through all-sky spectrum experiments, the average 21 cm signal of the cosmic dawn can be obtained by precisely measuring the low-frequency sky-averaged spectrum.

[0003] In all-sky spectrum experiments, the antenna is a crucial component of the measurement setup, used to receive sky signals and a key part for accurately detecting the 21cm average signal during the cosmic dawn. Since the measurement involves the all-sky average spectrum, the antenna must possess an extremely wide beamwidth to enable observation over a large sky area, rapidly accumulating signal-to-noise ratio. Within the observation frequency band, the antenna should have good impedance matching to reduce back-and-forth reflections between the antenna and receiver, ensuring a smooth frequency response, facilitating internal calibration of the measurement setup, and reproducing the true sky spectrum. The antenna pattern should be frequency-independent and have a smooth response to prevent the frequency-varying pattern from convolving the anisotropic structure of the foreground radiation into the spectral structure, thus avoiding confusion between the system response structure and the 21cm signal. Furthermore, the 50–100 MHz band is rife with radio frequency interference (RFI), requiring observations to be conducted at sparsely populated, electromagnetically quiet field sites, with simultaneous optimization of the antenna for ground environment adaptability. Therefore, a highly environmentally adaptable antenna for detecting the all-sky spectrum during the cosmic dawn is urgently needed. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a non-frequency-variable elliptic dipole antenna for spectrum measurement, in order to eliminate or improve one or more defects existing in the prior art.

[0005] This invention provides a non-frequency-variable elliptical dipole antenna for spectrum measurement, achieving broadband non-frequency-variable characteristics, an integrated antenna and receiver design, no balun coupling structure, and a smooth spectral response. It includes: a receiver, an antenna feeding structure, an antenna element, an internal support frame for the antenna element, a folding arm, and an antenna bracket. The antenna element comprises an elliptical cylindrical left antenna element and a right antenna element, both of which have internal support frames within their cavities. A housing for the receiver is fixed to the internal support frame inside the left antenna element. The antenna feeding structure is a pre-assembled feeding structure, including a left antenna side plate, a right antenna side plate, an RF coaxial cable, and a first radiator. The antenna includes a first RF connector and a second RF connector; the antenna feeding structure is detachably disposed between the left and right antenna elements via the left and right antenna side plates; the left antenna element is electrically connected to the housing of the first RF connector, and the right antenna element is electrically connected to the inner core of the second RF connector; the first RF connector is connected to the receiver via a feed line; the RF coaxial cable is located between the first and second RF connectors for connecting the two; one end of the folding arm is fixed to the left antenna element, and the other end is fixed to the right antenna element; the left and right antenna elements are fixed to the top surface of the antenna bracket, and the bottom surface of the antenna bracket is fixed to a flat plate.

[0006] In some embodiments of the present invention, the ratio of the major axis to the minor axis of the elliptical cylinder is 2, and the left antenna element and the right antenna element constitute an elliptical cylindrical dipole antenna.

[0007] In some embodiments of the present invention, the elliptical cylinders of the left and right antenna elements are formed by bending and splicing aluminum plates, including an elliptical cylinder side surface, a bottom surface, a flange, and a top cover. A hole is provided at the minor axis position of the elliptical cylinder side surface, and a rivet nut is installed around the hole for mounting the antenna feed structure. The flange, which is an elliptical ring, is provided at the upper edge of the elliptical cylinder side surface and is welded integrally with the elliptical cylinder side surface. A rivet nut is provided below the flange. The top cover is elliptical, and a mounting through hole is provided at the rivet nut position corresponding to the flange, so that the top cover is connected to the rivet nut on the flange by bolts. The bottom surface is elliptical and is tightly connected to the elliptical cylinder side surface by welding.

[0008] In some embodiments of the present invention, the antenna feeding structure further includes a feeding clamping device and an insulating gasket; wherein, the first RF connector is fixedly mounted on the inner side of the left antenna side plate by bolts; the left antenna side plate is connected to the left antenna vibrator by bolts, so that the housing of the first RF connector is electrically connected to the left antenna vibrator; the housing of the second RF connector is fixedly connected to the insulating gasket; the insulating gasket is located on the outer side of the right antenna side plate, and the feeding clamping device is located on the inner side of the right antenna side plate, and the three are fixedly connected by bolts; the insulating gasket and the right antenna side plate are provided with The inner core of the second RF connector passes through the through hole of the insulating pad and the right antenna side plate, and is clamped and fixed by the feed clamping device to make the inner core of the second RF connector electrically connected to the right antenna side plate; the right antenna side plate is connected to the right antenna vibrator by bolts to make the inner core of the second RF connector electrically connected to the right antenna vibrator; the feed clamping device is a combination of two copper blocks, which are connected vertically or horizontally, and the inner core of the second RF connector is clamped and disposed in the slot structure between the two copper blocks, and the inner core of the second RF connector is electrically connected to the two copper blocks.

[0009] In some embodiments of the present invention, the internal support frame of the antenna element is made of square aluminum tube; the internal support frame of the antenna element inside the left antenna element is the left support frame; wherein the left support frame includes a first part and a second part, the first part is welded and fixed to the side of the right antenna element, the second part is fixed to the first part, and the housing on which the receiver is fixed is fixed to the second part.

[0010] In some embodiments of the present invention, the internal support frame of the antenna vibrator inside the right antenna vibrator is a right support frame, which is welded from square aluminum tubes and is welded and fixed to the bottom and side surfaces of the right antenna vibrator.

[0011] In some embodiments of the present invention, the folding arm is formed by bending an aluminum tube, and two ear plates are provided at the two right-angle ends of the bend. The ear plates are welded and fixed to the aluminum tube. The ear plates are provided with through holes for fixing one end of the folding arm to the left antenna vibrator and the other end to the right antenna vibrator.

[0012] In some embodiments of the present invention, the antenna support is assembled from insulated fiberglass profiles, and the antenna support includes a left support and a right support. The top surfaces of the left support and the right support are flush, and the left antenna vibrator and the right antenna vibrator are respectively installed thereon.

[0013] In some embodiments of the present invention, a fiberglass square steel tube is installed on the top surface of the left-side bracket.

[0014] In some embodiments of the present invention, the bottom surfaces of the left and right antenna elements are designed to be 840mm above the ice surface; the height of the left and right supports is 1840mm; the left and right supports are each provided with a crossbeam; the distance from the top surface of the left and right supports to the lower surface of their respective crossbeams is 840mm; the portion of the crossbeams above the lower surface of the left and right supports is above the ice layer; the portion of the crossbeams below the lower surface of the left and right supports is within the ice layer.

[0015] This invention relates to a non-frequency-variable elliptical dipole antenna for spectrum measurement, comprising a receiver, an antenna feed structure, an antenna element, an internal support frame for the antenna element, a folding arm, and an antenna bracket. By directly mounting the receiver housing within the cavity of the antenna element, an integrated antenna-receiver design is achieved, eliminating the balun structure and significantly shortening the feed line length. This results in a smoother system frequency response, improves the overall integration of the measurement device, and facilitates antenna response calibration. Optimizing the antenna element's shape and structure alters the surface current distribution, enabling the antenna pattern to exhibit non-frequency-variable characteristics across a wide frequency range. Designing a detachable antenna feed structure in conjunction with the folding arm improves impedance matching and reduces signal reflection. Furthermore, a bracket is designed considering the antenna's shape and the ground characteristics of the actual operating environment, ensuring both the antenna's electrical performance and suitability for the actual conditions of the ground-based experimental environment.

[0016] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows, and will also become apparent in part to those skilled in the art upon studying the description, or may be learned by practice of the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures specifically pointed out in the description and drawings.

[0017] Those skilled in the art will understand that the objectives and advantages achievable with the present invention are not limited to those specifically described above, and that the above and other objectives achievable with the present invention will become clearer from the following detailed description. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, are not intended to limit the scope of the invention. The components in the drawings are not drawn to scale but are merely illustrative of the principles of the invention. For ease of illustration and description of certain parts of the invention, corresponding portions in the drawings may be enlarged, i.e., may appear larger relative to other components in an exemplary device actually manufactured according to the invention. In the drawings:

[0019] Figure 1 A schematic diagram of a non-frequency-varying elliptic dipole antenna used for spectrum measurement according to an embodiment of this specification is shown;

[0020] Figure 2 A schematic diagram showing an example of the external structure and dimensional parameters of an antenna vibrator according to an embodiment of this specification is provided.

[0021] Figure 3 A schematic diagram of an example of the internal support frame of an antenna vibrator according to an embodiment of this specification is shown;

[0022] Figure 4 A schematic diagram of an example of an antenna feeding structure according to an embodiment of this specification is shown;

[0023] Figure 5 A schematic diagram of an example of a folding arm according to an embodiment of this specification is shown;

[0024] Figure 6 A schematic diagram of the structure of an example of an antenna bracket according to an embodiment of this specification is shown;

[0025] Figure 7 A schematic diagram illustrating the simulation results of the beam of the non-frequency-variable elliptical dipole antenna at different frequencies according to the embodiments of this specification is shown.

[0026] Figure 8 A schematic diagram of the simulation results of the reflection coefficient of the non-frequency-varying elliptic dipole antenna according to an embodiment of this specification is shown.

[0027] Figure label:

[0028] 1-Receiver; 2-Antenna feeding structure; 21-Left antenna side plate; 22-First RF connector; 23-RF coaxial cable; 24-Right antenna side plate; 25-Second RF connector; 26-Feeding clamping device; 27-Insulating gasket; 3-Antenna element; 4-Internal support frame of antenna element; 5-Folding arm; 6-Antenna bracket. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0030] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0031] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, element, step, or component, but does not exclude the presence or addition of one or more other features, elements, steps, or components.

[0032] It should also be noted that, unless otherwise specified, the term "connection" in this article can refer not only to a direct connection, but also to an indirect connection involving an intermediary.

[0033] It is understood that the ordinal numbers such as "first" and "second" mentioned in this specification are only used to distinguish multiple objects of the same or different categories (such as components, steps, parameters, etc.), and do not indicate the priority, importance or order relationship between objects, nor do they constitute a limitation on the technical features.

[0034] In the following description, embodiments of the invention will be illustrated with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar parts, or the same or similar steps.

[0035] As mentioned earlier, there is an urgent need for an antenna optimized for real-world ground environments and applied to all-sky frequency experiments exploring the dawn of the universe.

[0036] Therefore, this specification provides a non-frequency-variable elliptical dipole antenna for spectrum measurement. This non-frequency-variable elliptical dipole antenna can be used in experiments to detect the entire sky spectrum during the dawn of the universe. It can be designed and installed at field sites with excellent electromagnetic environments. The antenna dimensions in this embodiment are optimized for ice surfaces.

[0037] like Figure 1 As shown, Figure 1 A schematic diagram of a non-frequency-variable elliptical dipole antenna used for spectrum measurement, according to an embodiment of this specification, is shown. Please refer to... Figure 1 The non-frequency variable elliptical dipole antenna used for spectrum measurement in the embodiments of this specification may include a receiver 1, an antenna feeding structure 2, an antenna element 3, an internal support frame for the antenna element 4, a folding arm 5, and an antenna bracket 6.

[0038] The antenna element 3 includes a left antenna element and a right antenna element, both of which are elliptical cylindrical. Each of the left and right antenna elements has an internal support frame 4 within its cavity. Here, because the edge transition of the elliptical cylindrical antenna is smoother, current can flow smoothly across the antenna's sides, resulting in better consistency of the antenna beam within the observation frequency band, i.e., better non-frequency-dependent performance, which is beneficial to the smoothness of the antenna system's response.

[0039] In this example, receiver 1 can be placed inside the receiver housing. The housing for holding receiver 1 is fixed on the internal support frame 4 of the antenna element inside the left antenna element.

[0040] The antenna feed structure 2 can be a pre-assembled feed structure, which may include a left antenna side plate, a right antenna side plate, an RF coaxial cable, a first RF connector, and a second RF connector. The antenna feed structure 2 can be detachably mounted between the left and right antenna elements via the left and right antenna side plates. The left antenna element is electrically connected to the housing of the first RF connector, and the right antenna element is electrically connected to the inner core of the second RF connector. The first RF connector is connected to the receiver via a feed line. The RF coaxial cable is located between the first and second RF connectors and is used to connect them. As an example, the first RF connector may include an SMA-KFKG RF connector, the second RF connector may include an SMA-KFD RF connector, and the RF coaxial cable may include an SMA RF coaxial cable. The first RF connector, the second RF connector, and the RF coaxial cable all have housings and inner cores, which are connected separately.

[0041] One end of the folding arm 5 is fixed to the left antenna vibrator, and the other end is fixed to the right antenna vibrator.

[0042] The left and right antenna elements are fixed to the top surface of the antenna bracket 6, and the bottom surface of the antenna bracket 6 is fixed to the flat plate.

[0043] Figure 1The non-frequency-variable elliptical dipole antenna shown employs a double elliptical cylindrical dipole design through a three-dimensional approach. This allows the all-sky spectrum receiver to be directly mounted within the antenna element's cavity, eliminating the need for a balun structure and significantly shortening the feed line length. This improves the overall integration of the measurement setup and facilitates antenna response calibration. Furthermore, by optimizing the antenna element's shape and altering the surface current distribution, the antenna pattern exhibits non-frequency-variable characteristics. A detachable antenna feed structure, combined with a folding antenna arm, improves impedance matching and reduces signal reflection. Considering the antenna's shape and the characteristics of the icy surface in the actual working environment, a high-strength fiberglass antenna truss support was designed, ensuring both the antenna's electrical performance and compliance with the ground characteristics of the experimental environment. Figure 1 The non-frequency-varying elliptic dipole antenna shown can operate in the 50-100MHz low-frequency radio band. By optimizing the antenna structure, it has good impedance matching and achieves a non-frequency-varying radiation pattern, meeting the experimental measurement requirements of the all-sky spectrum of the Cosmic Dawn and helping to extract the 21cm signal of the Cosmic Dawn.

[0044] Please continue reading Figure 2 , Figure 2 A schematic diagram illustrating an example of the external structure and dimensional parameters of the antenna element 3 according to an embodiment of this specification is shown. The antenna dimensions in this embodiment are optimized for an ice surface environment. Figure 2As shown, the non-frequency-variable antenna in this embodiment can be an elliptical cylindrical dipole antenna. The antenna element 3, including the left and right antenna elements, can be elliptical cylindrical. The internal cavities of the left and right antenna elements can have a certain installation space. The receiver housing can be installed in the left antenna element. A truss can be designed inside the right antenna element to improve its structural strength. In practice, the ratio of the major axis to the minor axis of the elliptical cylinder of the left and right antenna elements can be set according to actual needs. For example, the ratio of the major axis to the minor axis of the elliptical cylinder of the left and right antenna elements can be 2, the height h of the antenna's bottom surface from the ice surface can be 840 mm, the minor axis length r of the antenna elliptical cylinder can be 525 mm, the distance s between the two antenna elements can be 68 mm, and the thickness z of the elliptical cylinder of the antenna elements can be 200 mm. The left and right antenna elements can form an elliptical cylindrical dipole antenna. It is understood that the dimensional parameters of the antenna element 3 described above are merely illustrative and not limiting. In practice, other dimensional parameters can be set according to experimental needs, which will not be elaborated here. Furthermore, the antenna element 3 can be made of various metal materials (e.g., copper, aluminum, silver, etc.). For example, in some examples, the elliptical cylinder serves as the main antenna module, and 6061 aluminum alloy can be used as the primary material. The elliptical cylinders of the left and right antenna elements are formed by bending and splicing aluminum plates, including the elliptical cylinder's sides, bottom, flange, and top cover. Here, the elliptical cylinder's sides, bottom, and flange can be welded together. The welding process ensures a tight connection at the splice, guaranteeing good electromagnetic shielding.

[0045] As an example, the side of the elliptical cylinder can be made of aluminum plate with a thickness of 6mm, bent and spliced, and a hole is provided at the short axis position of the side of the elliptical cylinder, and a press-fit nut is installed around the hole to connect and fix the side plate of the antenna feed structure 2.

[0046] The upper edge of the side of the elliptical cylinder can be provided with an inward flange. The flange is an elliptical ring and is welded to the side of the elliptical cylinder as a whole. A press-fit nut is provided below the flange. For example, the flange can be made of a 3mm thick aluminum plate to form an elliptical ring, and a press-fit nut is installed below the flange using a press-fit process so that the top cover can be fixed by bolt connection.

[0047] The bottom surface is elliptical in shape. For example, the aluminum plate on the bottom surface can be 3mm thick and is tightly connected to the side of the elliptical cylinder by welding. In other words, the side, bottom, and flange of the elliptical cylinder can be tightly connected together by welding to form the main structure of the antenna element.

[0048] The top cover is elliptical in shape. For example, the top cover can be made of 3mm thick aluminum sheet, laser-cut. A mounting through-hole can be provided at the corresponding rivet nut position on the flange, allowing the top cover to be connected to the rivet nut on the flange via bolts, thus forming a complete elliptical cylinder.

[0049] Because the antenna surface of the antenna element 3 adopts a thin-shell design, in some examples, a support frame can be set inside the antenna surface to ensure the rigidity and stiffness of the antenna body. Therefore, this embodiment of the invention designs an internal support frame 4 for the antenna element.

[0050] Please continue reading Figure 3 , Figure 3 A schematic diagram of an example of the internal support frame 4 of the antenna vibrator according to an embodiment of this specification is shown. Figure 3 In the example shown, the internal support frame 4 of the antenna element may include a left support frame and a right support frame. The internal support frame 4 of the antenna element may be constructed of square aluminum tubing to achieve a lightweight design.

[0051] In this embodiment, the internal support frame of the antenna element inside the left antenna element is the left support frame. The left support frame may include a first part and a second part, and the first part and the second part may each include several square aluminum tubes. The first part is welded and fixed to the side of the right antenna element, which does not affect the installation and disassembly of the housing on which the receiver 1 is fixed, and the first part can provide a fixing point for the second part. The second part is fixed to the first part to improve the rigidity and strength of the main body of the left antenna element, and the housing of the receiver 1 can be fixed to the second part, preventing the weight of the receiver 1 from directly acting on the thinner antenna bottom surface, which could cause deformation or even damage to the antenna bottom surface.

[0052] In some examples, the internal support frame of the right antenna element is the right support frame, which can be welded from square aluminum tubes. The right support frame is welded together with the bottom and side surfaces of the right antenna element, making the antenna surface of the right antenna element and the right support frame an integral unit, thereby improving the antenna stiffness and strength and achieving the requirement of lightweight design.

[0053] Please continue reading Figure 4 , Figure 4 A schematic diagram of an example of the antenna feed structure 2 according to an embodiment of this specification is shown. Figure 4In the example shown, the antenna feed structure 2 employs a detachable design. The antenna feed structure 2 may include a left antenna side plate 21, a first RF connector 22, an RF coaxial cable 23, a right antenna side plate 24, a second RF connector 25, a feed clamping device 26, and an insulating gasket 27. The left antenna side plate 21 and the right antenna side plate 24 may be two detachably mounted aluminum plates. For example, the first RF connector 22 may include an SMA-KFKG RF connector, the second RF connector 25 may include an SMA-KFD RF connector, and the RF coaxial cable 23 may include an SMA RF coaxial cable. The first RF connector 22, the second RF connector 25, and the RF coaxial cable 23 all have a housing and an inner core, which are connected separately. The insulating gasket 27 may include a Teflon gasket.

[0054] The first RF connector 22 is fixedly mounted on the inner side of the left antenna side plate 21 by bolts. The left antenna side plate 21 can be bolted to the left antenna vibrator on which the receiver 1 is mounted, achieving a tight connection between the left antenna side plate 21 and the left antenna vibrator. This ensures that the outer shell of the first RF connector 22 is electrically connected to the left antenna vibrator, while the inner core of the first RF connector 22 is electrically isolated from the left antenna vibrator.

[0055] The housing of the second RF connector 25 is fixedly connected to the insulating gasket 27. The insulating gasket 27 is located on the outside of the right antenna side plate 24, and the feed clamping device 26 is located on the inside of the right antenna side plate 24. The three are fixedly connected by bolts. Through holes are provided in the insulating gasket 27 and the right antenna side plate 24. The inner core of the second RF connector 25 passes through the through holes in the insulating gasket 27 and the right antenna side plate 24 and is clamped and fixed by the feed clamping device 26, so that the inner core of the second RF connector 25 is electrically connected to the right antenna side plate 24. The right antenna side plate 24 is bolted to the right antenna element, so that the inner core of the second RF connector 25 is electrically connected to the right antenna element. Here, the insulating gasket 27 ensures electrical isolation between the housing of the second RF connector 25 and the right antenna side plate 24.

[0056] The power supply clamping device 26 is a combination of two copper blocks, which are connected vertically or horizontally. The inner core of the second RF connector 25 is clamped within a slot-shaped structure between the two copper blocks, and the inner core of the second RF connector 25 is electrically connected to the two copper blocks. Figure 4In the example shown, the upper and lower copper blocks of the feed clamping device 26 can be an inverted U-shaped copper block and a rectangular copper block, respectively. The rectangular copper block is shorter and can be inserted into the inverted U-shaped copper block. Specifically, the upper inverted U-shaped copper block can be fixed to the right antenna side plate 24 through two pairs of bolts and nuts shared with the insulating gasket 27 via horizontal through holes, so that the inverted U-shaped copper block is electrically connected to the right antenna side plate 24 and isolated from the housing of the second RF connector 25. The inverted U-shaped copper block has two vertical through holes, and the corresponding lower rectangular copper block has two vertical threaded holes. Bolts can be screwed into the two vertical threaded holes of the lower rectangular copper block through the two vertical through holes of the inverted U-shaped copper block to clamp the inner core of the second RF connector 25, thereby electrically connecting the inner core of the second RF connector 25 to the right antenna side plate 24. The right antenna side plate 24 can be fixedly connected to the right antenna vibrator with bolts.

[0057] The left antenna side plate 21 and the right antenna side plate 24 can be connected by an RF coaxial cable 23. Specifically, the RF coaxial cable 23 is connected to the first RF connector 22 mounted on the left antenna side plate 21 and the second RF connector 25 mounted on the right antenna side plate 24, respectively. This antenna feeding structure 2 allows for the feeding design of an elliptical cylindrical dipole antenna. The receiver is installed inside the left antenna element and can be connected to the outer shell and inner core of the first RF connector 22 mounted on the left antenna side plate 21 via a very short feed line, thus enabling antenna signal transmission.

[0058] See also Figure 5 , Figure 5 A schematic diagram of an example of the folding arm 5 according to an embodiment of this specification is shown. Figure 5 In the example shown, the folding arm 5 of the elliptical cylindrical dipole antenna can be formed by bending an aluminum tube. For example, an aluminum tube with an outer diameter of 20mm and a wall thickness of 3mm can be bent to form a long straight rod with right-angle bends at both ends. Two lugs are provided at the two right-angle ends of the bends, and the lugs are welded to the aluminum tube. Specifically, they are fixed to the two bent ends of the folding arm 5 by welding. The lugs are provided with through holes for fixing one end of the folding arm 5 to the left antenna element and the other end to the right antenna element. Specifically, the folding arm 5 can be tightly installed on the two antenna elements by bolts and nuts using the two lugs and the pre-installed rivet nuts on the two antenna elements.

[0059] Please see Figure 6 , Figure 6 A schematic diagram of an example of the antenna support 6 according to an embodiment of this specification is shown. Figure 6In the example shown, the antenna support 6 can be assembled from insulated fiberglass profiles, providing good rigidity to withstand complex outdoor environments. The antenna support 6 can adopt a truss design. Figure 6 The antenna bracket 6 shown in the example may include a left bracket and a right bracket, with their top surfaces flush. These brackets are used to mount the left and right antenna elements, respectively, preventing stress concentration that could damage the antenna. The antenna bracket 6 ensures the antenna elements are at the required design height from the ground, and this height also prevents the antenna from being covered by snow or water in rainy or snowy weather, ensuring the antenna and its internal receiver can function normally. The antenna bracket 6 has corresponding mounting holes machined on its top to secure the two antenna elements, ensuring the spacing between them conforms to the antenna's design parameters and that the antenna performance meets the expected design specifications. As an example, the structures of the left and right brackets may be essentially the same or different.

[0060] In some examples, since the receiver 1 is installed in the left antenna element and is relatively heavy, in order to avoid deformation and damage to the antenna base plate, a fiberglass square steel tube can be installed on the top surface of the left bracket to support the receiver housing 1 and reduce the stress on the antenna base.

[0061] In some examples, the bottom surfaces of the left and right antenna elements can be designed to be 840mm above the ice surface. Based on this, the height of the left and right supports can be set to 1840mm. Each of the left and right supports can be equipped with a crossbeam. The distance from the top surface of the left and right supports to the lower surface of their respective crossbeams can be 840mm, with the 840mm portion above the lower surface of the crossbeams of the left and right supports positioned above the ice layer. In other words, the portion from the top surface of the left support to the lower surface of its crossbeam is exposed above the ice surface, and similarly, the portion from the top surface of the right support to the lower surface of its crossbeam is also exposed above the ice surface, ensuring that the antenna's height above the ground is consistent with the antenna simulation design and guaranteeing the antenna's electrical performance parameters. The 1000mm portion below the lower surface of the crossbeams of the left and right supports is embedded in the ice layer. This means that the lower 1000mm portion of the left and right supports is buried in the ice layer to prevent the antenna from tipping over in strong winds. The antenna system structure in this embodiment has a relatively large mass. To prevent the antenna from sinking after installation and affecting its electrical performance, two large flat plates are designed at the bottom of the support frame. Specifically, the bottom surfaces of the left and right support frames can be connected to the two large flat plates (e.g., wooden boards). By designing wooden boards under the support frame, the contact area with the ice surface is increased, which can prevent or greatly reduce the sinking of the antenna system structure.

[0062] See also Figure 7 , Figure 7A schematic diagram illustrating simulation results of the beam at different frequencies for a non-frequency-varying elliptical dipole antenna according to an embodiment of this specification is shown. Figure 7 In the example shown, the curves of different colors correspond to the E-plane normalized radiation patterns when the antenna operates at different frequencies. For instance, the 67.859 in the green label represents the half-power beamwidth of the E-plane radiation pattern when the antenna operates at 60MHz. Figure 7 It can be seen that in the far field, the half-power beamwidth difference at different frequencies is 5.62°, indicating that the elliptical dipole antenna designed in the embodiments of this specification has a consistent beam within the 50-100MHz operating frequency band, realizing the non-frequency-varying design of the antenna.

[0063] See also Figure 8 , Figure 8 A schematic diagram illustrating the simulation results of the reflection coefficient of a non-frequency-varying elliptical dipole antenna according to an embodiment of this specification is shown. Figure 8 In the example shown, the horizontal axis represents frequency, and the vertical axis represents the logarithmic form of the reflection coefficient. The blue curve represents the antenna's reflection coefficient in the 50-100MHz frequency band. The reflection coefficient describes the antenna's impedance matching; a smaller reflection coefficient indicates better impedance matching. Figure 8 As can be seen, the elliptical dipole antenna in the embodiments of this specification has a reflection coefficient of less than -12dB in the 50-100MHz operating frequency band, indicating that the antenna has excellent impedance matching in the required observation frequency band.

[0064] As can be seen from the above, in the embodiments of this specification, the elliptical dipole antenna adopts an antenna design with a smoothly transitioned elliptical cylindrical surface. This optimizes the current distribution on the antenna surface, ensuring that the current can flow smoothly across the sides of the antenna, thus ensuring good consistency of the antenna beam across the observation frequency band and achieving non-frequency-varying characteristics over a wide frequency range. The non-frequency-varying elliptical dipole antenna design uses a double elliptical cylindrical dipole form, providing good impedance matching within the required observation frequency band of 50-100MHz. The antenna's S11 parameters (also known as return loss or reflection coefficient) are all less than -12dB. Simultaneously, it achieves non-frequency-varying characteristics, with a half-power beamwidth range of less than 5.62°, exhibiting excellent beam consistency. This prevents the frequency-varying radiation pattern from convolving the anisotropic structure of the foreground radiation into the spectral structure, avoiding confusion between the system response structure and the 21 cm signal. The beam of this non-frequency-varying antenna points towards the zenith, significantly reducing the influence of environmental interference signals from the horizontal direction. The designed non-frequency-variable antenna adopts an integrated three-dimensional design concept, with the receiver directly mounted inside the antenna cavity, significantly reducing the feed line length between the antenna and receiver. Furthermore, the shielding of the antenna housing eliminates the influence of feed line housing current radiation on the antenna pattern, thus eliminating the need for balun structure and loss correction for balun and feed lines. This improves the measurement accuracy of the all-sky spectrum measurement device and greatly enhances the integration of the entire Cosmic Dawn all-sky spectrum measurement system, facilitating installation and deployment in complex field environments. The detachable antenna feed structure design improves the ease of disassembly and assembly of the elliptical cylindrical dipole antenna and enhances the safety of antenna transportation. Additionally, during actual antenna debugging and installation, fine-tuning the detachable antenna feed structure further optimizes the antenna's impedance matching.

[0065] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures.

[0066] In this invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or in place of features of other embodiments.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations of the embodiments of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A non-frequency variant elliptical dipole antenna for spectrum measurement, characterized in that, The utility model relates to a kind of antenna, including: Receiver, antenna feed structure, antenna element, antenna element internal support frame, folding arm and antenna support, wherein, The antenna element includes left antenna element and right antenna element of elliptic cylinder, and the cavity inside the left antenna element and the right antenna element is provided with antenna element internal support frame; The antenna element internal support frame inside the left antenna element is fixed with the box body of placing the receiver; The antenna feed structure is pre-assembled feed structure, and the antenna feed structure includes left antenna side plate, right antenna side plate, radio frequency coaxial line, first radio frequency connector and second radio frequency connector;The antenna feed structure is detachably arranged between the left antenna element and the right antenna element by the left antenna side plate and the right antenna side plate;The left antenna element is electrically connected with the shell of the first radio frequency connector, and the right antenna element is electrically connected with the inner core of the second radio frequency connector;The first radio frequency connector is connected with the receiver by feeder;The radio frequency coaxial line is located between the first radio frequency connector and the second radio frequency connector, and is used for connecting the two; One end of the folding arm is fixed on the left antenna element, and the other end is fixed on the right antenna element; The left antenna element and the right antenna element are fixed on the top surface of the antenna support, and the bottom surface of the antenna support is fixed on the flat plate.

2. The non-frequency variant elliptical dipole antenna for spectrum measurement according to claim 1, characterized in that, The ratio of the major axis and the minor axis of the elliptic cylinder is 2, and the left antenna element and the right antenna element form an elliptic cylinder dipole antenna.

3. The non-frequency variant elliptical dipole antenna for spectrum measurement according to claim 1, characterized in that, The elliptic cylinder of the left antenna element and the right antenna element is made of aluminum sheet, including elliptic cylinder side, bottom, flange and upper cover;Among them, The minor axis position of the elliptic cylinder side is provided with a hole, and a press-in nut is installed around the hole for installing the antenna feed structure; The upper edge of the elliptic cylinder side is provided with the flange, and the flange is an elliptic ring, which is welded with the elliptic cylinder side as a whole, and the lower part of the flange is provided with a press-in nut; The upper cover is elliptical, and the upper cover is provided with a mounting through-hole position corresponding to the press-in nut position of the flange, so that the upper cover is connected with the press-in nut on the flange through bolt; The bottom is elliptical, and is tightly connected with the elliptic cylinder side by welding.

4. The non-frequency variant elliptical dipole antenna for spectrum measurement of claim 1, wherein, The antenna feed structure further includes feed clamping device and insulating gasket;Among them, The first radio frequency connector is fixedly installed in the left antenna side plate by bolt; The left antenna side plate is connected to the left antenna element by bolt, so that the shell of the first radio frequency connector is electrically connected with the left antenna element; The shell of the second radio frequency connector is fixedly connected on the insulating gasket. The insulating pad is located outside the right antenna side plate, and the feeding clamp is located inside the right antenna side plate, and the three are fixedly connected by bolts; the insulating pad and the right antenna side plate are provided with through holes, the inner core of the second radio frequency connector passes through the through holes of the insulating pad and the right antenna side plate, and is clamped and fixed by the feeding clamp, so that the inner core of the second radio frequency connector is electrically connected with the right antenna side plate; The right antenna side plate is connected to the right antenna oscillator by bolts, so that the inner core of the second radio frequency connector is electrically connected with the right antenna oscillator; The feeding clamp is a combination of two copper blocks, which are connected in an up-down or left-right manner, and the inner core of the second radio frequency connector is clamped in the groove structure between the two copper blocks, and the inner core of the second radio frequency connector is electrically connected with the two copper blocks.

5. The non-frequency variant elliptical dipole antenna for spectrum measurement of claim 1, wherein, The antenna oscillator internal support frame is composed of square aluminum pipes; the antenna oscillator internal support frame inside the left antenna oscillator is a left support frame; wherein, The left support frame includes a first part and a second part, the first part is welded and fixed with the side surface of the right antenna oscillator, the second part is fixed with the first part, and the box of the receiver is fixed on the second part.

6. The non-frequency variant elliptical dipole antenna for spectrum measurement according to claim 5, characterized in that, The antenna oscillator internal support frame inside the right antenna oscillator is a right support frame, which is welded by square aluminum pipes, and the right support frame is welded and fixed with the bottom surface and the side surface of the right antenna oscillator.

7. The non-frequency variant elliptical dipole antenna for spectrum measurement of claim 1, wherein, The folding arm is bent from an aluminum pipe, two ear plates are arranged at the two straight angle ends of the folding arm, the ear plates are welded and fixed with the aluminum pipe, and through holes are arranged on the ear plates for fixing one end of the folding arm on the left antenna oscillator and the other end on the right antenna oscillator.

8. The non-frequency variant elliptical dipole antenna for spectrum measurement of claim 1, wherein, The antenna support is assembled by insulating glass steel profiles, and the antenna support includes a left support and a right support, the top surfaces of the left support and the right support are flush, and the left antenna oscillator and the right antenna oscillator are respectively installed.

9. The non-frequency variant elliptical dipole antenna for spectrum measurement of claim 8, wherein, A glass fiber square steel pipe is installed on the top surface of the left support.

10. The non-frequency variant elliptical dipole antenna for spectrum measurement of claim 8, wherein, The distance between the bottom surfaces of the left antenna oscillator and the right antenna oscillator and the ice surface is designed as 840 mm; the height of the left support and the right support is 1840 mm; the left support and the right support are respectively provided with cross beams, the distance between the top surfaces of the left support and the right support and the lower surfaces of the respective cross beams is 840 mm, the part above the lower surfaces of the cross beams of the left support and the right support by 840 mm is arranged above the ice layer, and the part below the lower surfaces of the cross beams of the left support and the right support by 1000 mm is arranged in the ice layer.

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