Antenna

Abstract

Shown is an antenna (20) having a first and a second radiating element (22a, 22b) and a first and a second electrically conductive plate (28a, 28b). The first and the second radiating element (22a, 22b) are each designed to transmit and / or receive electromagnetic radiation, wherein the first and the second radiating element (22a, 22b) each taper, wherein a first end face (24a) of the first radiating element (22a) is located at the taper of the first radiating element. A first end face (24b) of the second radiating element (22b) is located at the taper of the second radiating element, wherein the first end face (24a) of the first radiating element is arranged opposite the first end face (24b) of the second radiating element. The first electrically conductive plate (28a) is arranged at a second end face (26a) of the first radiating element and the second electrically conductive plate (28b) is arranged at a second end face (26b) of the second radiating element. Between the first electrically conductive plate (28a) and the first radiating element (22a), and between the second conductive plate (28b) and the second radiating element (22b), there is the absence of an electrical connection.

Description

[0001] The invention relates to a broadband dipole antenna with an inhomogeneity in the longitudinal direction, in particular a biconical antenna.

[0002] The bandwidth of broadband dipole antennas with longitudinal inhomogeneity, especially biconical antennas, depends primarily on the length, the angle (in the case of biconical antennas), or more generally, the shape of the inhomogeneity and the height of the two radiators. Therefore, these antennas can become quite large if they are intended for broadband transmission and reception. However, there are installation situations, particularly on watercraft, where space for integrating a biconical broadband antenna is limited.

[0003] JP 2015 103912 A shows a biconical antenna in which a propagation characteristic is improved by reducing the directivity in the zenith direction and rotating the energy for a reduced component in the horizontal direction.

[0004] HE SHUAI ET AL: "Design of a Compact Biconical Antenna Loaded With Magnetic Dipoles", IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, Vol. 16, April 10, 2017 (2017-04-10), pages 840-843, XP011645712, discloses a compact biconical ultra-wideband antenna with an impedance bandwidth of 200 and 965 MHz for VSWR (voltage standing wave ratio) less than 2.35.

[0005] AMERT AK ET AL: "Miniaturization of the Biconical Antenna for Ultrawideband Applications", IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, IEEE, USA, BD 57, No. 12, December 1, 2009 (2009-12-01), pages 3728-3735, XP011281931 discloses a miniaturized ultrawideband antenna for the frequency band between 3.1 and 10.6 GHz.

[0006] US 6 268 834 B1 reveals a biconical antenna with a guide for cables to at least one other antenna.

[0007] The object of the present invention is therefore to create an improved concept for broadband dipole antennas with longitudinal inhomogeneity.

[0008] The problem is solved by the subject matter of the independent patent claims. Further advantageous embodiments are the subject matter of the dependent patent claims.

[0009] In the following, the broadband dipole antenna with longitudinal inhomogeneity will be referred to simply as a dipole antenna. However, at no point in this explanation is there any reference to the classic dipole with two cylinders as radiators.

[0010] Exemplary embodiments show an antenna with a first and a second radiator, each configured to emit and / or receive electromagnetic radiation. Both the first and second radiators taper. This taper results in longitudinal inhomogeneity of the antenna. A first end face of the first radiator is located at the taper of the first radiator, and a first end face of the second radiator is located at the taper of the second radiator. The first end face of the first radiator is positioned opposite the first end face of the second radiator. Two radiators arranged in this way are called a dipole. A tapered radiator can, for example, have a biconical shape, an elliptical shape, or be hemispherical. Furthermore, it is not necessary for the second end face to have the largest cross-section of the respective radiator.The diameter is advantageously measured perpendicular to the direction in which the first and second radiators are arranged (sequentially). This means that it is also possible for the radiators to taper towards the second end face. Typically, however, the degree of taper towards the first end face is greater than towards the second. Furthermore, the antenna is typically designed to be mirror-symmetrical.

[0011] The radiators, i.e., the dipole, are typically fed at their first two ends, i.e., between the two radiators. For this purpose, an electrical conductor can run through the first radiator, contacting the first and / or the second radiator at its first end. This electrical conductor can be a coaxial cable, with its outer conductor contacting one radiator and its inner conductor contacting the other (asymmetrical contacting, also known as single-ended feeding). Alternatively, a second electrical conductor can be provided, with the first connecting one radiator and the second connecting the other. In this case, the electrical conductors are also coaxial, so that the inner conductors of each of the two conductors connect to a different radiator.The signal can be generated here using a balun (balancing element) for both lines. In this case, too, the electrical line and / or the other electrical line can be a coaxial cable.

[0012] The antenna further comprises a first and a second electrically conductive plate. The first electrically conductive plate is positioned at the second end face of the first radiator, and the second electrically conductive plate is positioned at the second end face of the second radiator. In other words, the two radiators are located between the two plates. There is no electrical connection between the first conductive plate and the first radiator, nor between the second conductive plate and the second radiator. Therefore, an air gap or an electrically insulating material is located between the plates and the radiators. Some plastics that can be used as electrically insulating materials are listed below.

[0013] The idea of ​​the present invention is to reduce the volume of the broadband antenna while maintaining its bandwidth. It has been shown that arranging the radiators between the electrically conductive plates shifts the resonant frequency of the broadband antenna to lower frequencies. Thus, signals of a lower frequency can be radiated with the same antenna. This allows the size of the radiators to be significantly reduced. A further advantage of this antenna is its insensitivity to interference from objects located outside the two electrically conductive plates. Therefore, this antenna can advantageously be used in a multi-function antenna. Additional antennas, transmitting or receiving in other frequency ranges, can be arranged above and / or below the main antenna.

[0014] In exemplary embodiments, the first electrically conductive plate completely covers at least the second end face of the first emitter, and the second electrically conductive plate completely covers at least the second end face of the second emitter. In other words, the diameter of the first conductive plate is larger than the (particularly maximum) diameter of the first emitter. Advantageously, the diameter is measured perpendicular to the direction in which the first and second emitters are arranged (sequentially). Put another way, the projection of the first emitter onto the plane of the conductive first plate is smaller than the conductive first plate itself. The same applies to the second emitter and the second plate. This fully utilizes the effect of the emitters becoming smaller.

[0015] According to the invention, the first and second electrically conductive plates are connected by means of a plurality of posts. The posts extend through a surface of the first and second radiators. The posts of the plurality of posts are therefore typically arranged within a perpendicular projection of the second end face of the first and second radiators, respectively. In other words, the posts are supported on the first and second electrically conductive plates. The posts stabilize the antenna, enabling it to withstand greater mechanical loads.

[0016] However, the posts offer further advantages in various antenna designs.

[0017] First, the posts can be electrically conductive, meaning they are made of or have an electrically conductive material. The antenna impedance can then be adjusted using the posts. This process is also known as antenna tuning. For example, the posts influence the feed point impedance of the antenna and thus affect the frequencies that can be preferentially radiated by the antenna. Furthermore, the bandwidth of the antenna is affected by the posts. A clever positioning of the posts can therefore have little or no impact on the radiation pattern of the antenna compared to an antenna without posts, but the posts can also provide the antenna with the advantages described above. Advantageously, the posts are electrically conductive in this case. Then the posts represent an adjustable parameter for the antenna, allowing the aforementioned properties to be set.

[0018] Furthermore, it is advantageous to arrange the posts symmetrically to achieve a positive effect on the radiation pattern. A symmetrical arrangement of the posts means, for example, that the angle between adjacent posts is the same for all posts in the majority of the group. The plane in which the angle is measured is advantageously perpendicular to the direction in which the radiators are arranged (sequentially). It is also advantageous if the posts in the majority of the group have no electrical connection to the first and second radiators. Otherwise, an undesirable electrical connection would be established between the electrically conductive plates and the radiators via the electrically conductive posts.

[0019] Furthermore, the posts can be hollow. If an electrical component is located on the side of the second plate facing away from the second radiator, an electrical conductor can be routed through one of the posts to connect the component. The conductor is then routed eccentrically, i.e., not through the center of the radiators, which would otherwise create parasitic resonances or cause an antenna mismatch, both of which negatively affect the antenna's characteristics. By routing the conductor eccentrically to connect the component, these high-frequency effects are reduced or even avoided. Thus, the antenna's radiation pattern is (essentially) maintained despite the presence of an electrical conductor. The electrical component could be, for example, another antenna.A GPS antenna (GPS: Global Positioning System) or a collinear antenna array can be used. This allows for the creation of an antenna array or a multi-function antenna.

[0020] In the aforementioned embodiments, the number of posts in the plurality of posts is advantageously at least three. This allows the aforementioned advantages to materialize significantly.

[0021] The resulting antenna can be operated in a frequency range between 950 MHz and 1275 MHz. Furthermore, the antenna can have a spacing of less than 60 mm, preferably less than 55 mm, for example 51 mm, between the first and second plates. An antenna with the same characteristics would be at least 76 mm in diameter without the two electrically conductive plates, and thus approximately 50% larger (assuming a noise-free biconical dipole). The antenna can be operated as a vertically polarized dipole antenna with omnidirectional radiation characteristics in the azimuth.

[0022] Its small size and insensitivity to other antennas positioned above or below it make the dipole antenna an ideal multi-purpose antenna. Known broadband dipole antennas with longitudinal inhomogeneity radiate asymmetrically when another object, such as another antenna, is present. However, this broadband dipole antenna continues to radiate symmetrically, even when other antennas are positioned above and / or below it.

[0023] In exemplary embodiments, any selection of the following non-electrically interconnected antenna components can be mechanically connected using a plastic: the electrically conductive plates to the adjacent radiator (at the second end face), both radiators (between the first end faces), and the radiators to the posts. Examples of plastics used include acrylonitrile butadiene styrene (ABS), polyoxymethylene (POM), polyetherketone (PEEK), polyethylene (PE), or another non-conductive plastic.

[0024] In exemplary embodiments, a dielectric material is arranged between the first end face of the first radiator and the first end face of the second radiator. This is advantageous because it increases the mechanical stability of the antenna and prevents electrical discharges when using high transmit powers. Furthermore, the dielectric material provides an additional way to adjust the antenna input impedance. Thus, it is possible to adjust the antenna input impedance using the dielectric material alone, or, when using electrically conductive posts, in addition to them. Polytetrafluoroethylene (PTFE, commonly known as Teflon) can be used as a dielectric material, for example.

[0025] Analogously, a method for manufacturing an antenna is disclosed comprising the following steps: arranging a first and a second radiator between a first and a second electrically conductive plate such that there is no electrical connection between the first conductive plate and the first radiator and that there is no electrical connection between the second conductive plate and the second radiator, wherein the first and the second radiator each taper towards one end and the tapered ends are opposite each other.

[0026] Preferred embodiments of the present invention are explained below with reference to the accompanying drawings. These show: Fig. 1 : a schematic side view of an antenna in an exemplary embodiment; Fig. 2 : a schematic side view of the antenna in a further embodiment; Fig. 3 : a schematic perspective representation of a first and a second radiator of the antenna of the exemplary embodiment from Fig. 2 .

[0027] Before exemplary embodiments of the present invention are explained in detail below with reference to the drawings, it should be noted that identical, functionally equivalent or equivalent elements, objects and / or structures in the different figures are provided with the same reference numerals, so that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to one another.

[0028] Fig. 1 Figure 1 shows an embodiment of an antenna 20 in a side view. The antenna 20 has a first radiator 22a and a second radiator 22b. The radiators 22a and 22b are each configured to emit and / or receive electromagnetic radiation. Both radiators 22a and 22b are arranged such that a taper, which each radiator 22a and 22b has, faces each other. If the radiators have a taper in two directions, the two narrower ends of the radiators face each other. The end of each radiator 22a and 22b is referred to as the first end face 24a and 24b, respectively, and the opposite end of each radiator 22a and 22b is referred to as the second end face 26a and 26b, respectively.

[0029] The emitters 22a, 22b are arranged between a first conductive plate 28a and a second conductive plate 28b. That is, the first conductive plate 28a is located at the second end face 26a of the first emitter, and the second conductive plate 28b is located at the second end face 26b of the second emitter 22b. There is no electrical connection between the conductive plates 28a, 28b and the emitters 22a, 22b. The spaces 30a, 30b between the plates 28a, 28b and the emitters 22a, 22b can be filled with an electrically insulating material, for example, a suitable plastic. This creates a mechanical connection between the emitters and the plates. Furthermore, the two emitters are not electrically connected to each other.For this purpose, an electrically insulating material, for example a suitable plastic, can also be arranged in an intermediate space 30c between the first end faces 24a, 24b.

[0030] Radiators 22a and 22b form a biconical antenna. Other shapes are also possible. Advantageously, the antenna 20, or at least the radiators 22a and 22b, exhibits mirror symmetry with respect to a mirror plane 32. The mirror plane 32 advantageously runs in the direction (y-direction) in which the first and second radiators are arranged sequentially. Optionally, another mirror plane (not shown) can run perpendicular to the direction (y-direction) in which the first and second radiators are arranged sequentially between the first and second radiators 22a and 22b (i.e., in the x-direction).

[0031] Fig. 2 Figure 1 shows another embodiment of the antenna 20 in a side view. Here, electrically non-conductive materials in the form of an intermediate layer 30a', 30b', 30c' are now inserted into the former gaps.

[0032] Furthermore, the antenna 20 has a plurality of posts 34 (here four posts 34a, 34b, 34c, 34d). The posts 34 connect the first electrically conductive plate 28a to the second electrically conductive plate 28b. Initially, this is a mechanical connection to increase the stability of the antenna 20. The posts 34 can be electrically conductive. If so, they exert a load on the antenna 20, so that the antenna can be tuned (tuned) by adjusting the diameter and / or position of the posts. In this case, the posts are, as shown in Fig. 2 As shown, the posts are arranged symmetrically. Advantageously, they are positioned perpendicularly between the first and second conductive plates. This provides maximum mechanical stability and prevents asymmetrical wave propagation, which would otherwise be possible.

[0033] Furthermore, at least one of the majority of posts 34 can be hollow. A conductor 36 can be routed through the first post 34a, which makes (electrical) contact with an electrical component 38. If the posts 34a are electrically non-conductive, it is advantageous to route an electrical conductor through each post to avoid an unbalanced load on the antenna. If the posts are electrically conductive, the conductors can be neglected with regard to the load on the antenna.

[0034] The electrical component 38 is, for example, another radiator, making the antenna 20 a multi-functional antenna. The line 36 is typically a coaxial line. The line 36 can be routed through a suitable guide tube 36'. A plurality of lines can be routed in the guide tube 36', for example, a line for connecting the first radiator 22a and the second radiator 22b. The guide tube 36' is shown here in a central position. However, it is also possible to arrange the guide tube 36' eccentrically, for example, below the post 34a through which the line 36 is routed. The line 36 can then be routed in a straight line and does not need to be curved.

[0035] The posts 34 have no electrical connection to the spotlights 22a, 22b. At the point where the posts pass through the surface of the respective spotlight, the posts are spaced apart from the surface of the respective spotlight. The resulting gap can also be filled with a non-electrically conductive material, as was already done with gaps 30a, 30b, 30c. Fig. 1 .

[0036] Fig. 3 shows the radiators 22a, 22b of the antenna according to the embodiment shown in Figure 1. Fig. 2 Here it becomes clear that the emitters 22a, 22b each have openings 40 in their surface through which the posts can pass. The openings 40 are slightly larger in diameter than the diameters of the posts so that the posts do not touch the emitters 22a, 22b, or so that a gap remains which can be filled with an electrically non-conductive material.

[0037] Although some aspects have been described in connection with a device, it is understood that these aspects also constitute a description of the corresponding process, so that a block or component of a device can also be understood as a corresponding process step or as a feature of a process step. Similarly, aspects described in connection with or as a process step also constitute a description of a corresponding block, detail, or feature of a corresponding device.

[0038] The embodiments described above merely illustrate the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be obvious to other people skilled in the art. Therefore, it is intended that the invention be limited only by the scope of protection set forth in the following claims and not by the specific details presented herein by way of description and explanation of the embodiments. Reference symbol list:

[0039] 20 Antenna 22a, 22b Radiator 24a, 24 Top end face 26a, 26b Second end face 28a, 28b Electrically conductive plate 30 Gaps 32 Mirror plane 34 Post 36 Line 38 Electrical component 40 Opening

Claims

1. Antenna (20) with the following features: a first and a second radiator (22a, 22b), each configured to transmit and / or receive electromagnetic radiation, wherein the first and the second radiator (22a, 22b) each taper, wherein a first end face (24a) of the first radiator (22a) is located at the taper of the first radiator and wherein a first end face (24b) of the second radiator (22b) is located at the taper of the second radiator, wherein the first end face (24a) of the first radiator is arranged opposite the first end face (24b) of the second radiator; a first and a second electrically conductive plate (28a, 28b), wherein the first electrically conductive plate (28a) is arranged at a second end face (26a) of the first radiator and wherein the second electrically conductive plate (28b) is arranged at a second end face (26b) of the second radiator; wherein between the first conductive plate (28a) and the first radiator (22a) there is an absence of an electrical connection and wherein between the second conductive plate (28b) and the second radiator (22b) there is an absence of an electrical connection; wherein the first and the second electrically conductive plate (28a, 28b) are connected by means of a plurality of posts (34), characterized in that the posts (34) pass through a surface of the first and the second radiator.

2. Antenna (20) according to claim 1, wherein an electrical line is guided through the first radiator (22a), which contacts the first and / or the second electrical radiator (22b) at the first end face (24b).

3. Antenna (20) according to one of the preceding claims, wherein the first electrically conductive plate (28a) completely covers at least the second end face (26a) of the first radiator; and / or wherein the second electrically conductive plate (28b) completely covers at least the second end face (26b) of the second radiator.

4. Antenna (20) according to one of the preceding claims, wherein an electrical component (38) is arranged on the side of the second plate (28) facing away from the second radiator (22b); wherein an electrical line (36) is guided through a first post (34a) of the plurality of posts (34) in order to contact the electrical component (38).

5. Antenna (20) according to one of the preceding claims, wherein the posts (34a, 34b, 34c, 34d) of the plurality of posts (34) are arranged symmetrically.

6. Antenna (20) according to one of the preceding claims, wherein the posts (34a, 34b, 34c, 34d) of the plurality of posts (34) have an absence of an electrical connection to the first and the second radiator (22a, 22b).

7. Antenna (20) according to one of the preceding claims, wherein the posts (34a, 34b, 34c, 34d) of the plurality of posts (34) are electrically conductive.

8. Antenna (20) according to one of the preceding claims, wherein the posts (34a, 34b, 34c, 34d) of the plurality of posts (34) are arranged within a perpendicular projection of the second end face of the first or the second radiator.

9. Antenna (20) according to one of the preceding claims, wherein a dielectric material is arranged between the first end face (24a) of the first radiator (22a) and the first end face (24b) of the second radiator (22b).

10. Method for manufacturing an antenna (20) with the following steps: - Arranging a first and a second radiator between a first and a second electrically conductive plate (28a, 28b) such that between the first conductive plate (28a) and the first radiator (22a) there is an absence of an electrical connection and that between the second conductive plate (28b) and the second radiator (22b) there is an absence of an electrical connection, wherein the first and the second radiator (22a, 22b) taper toward one end and the tapered ends face each other; - Connecting the first and the second electrically conductive plate (28a, 28b) by means of a plurality of posts (34), characterized in that the posts (34) pass through a surface of the first and the second radiator.

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