Antenna arrangement with circularly polarized antenna elements on a head of a body

Abstract

Antenna arrangement (110, 210, 310), comprising: a head of a body; and a plurality M of antenna elements (m) arranged on the head (110) of the body and outside the body; wherein the plurality M of antenna elements (m) each comprise a housing (211), a tip (212), and an antenna (213), the antenna (213) having the shape of an elongated helix extending in a longitudinal direction of the antenna arrangement (110, 210, 310).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to antenna arrangements, in particular to an antenna arrangement with circularly polarized antenna elements on a head of a body for applications in radar technology. BACKGROUND OF THE INVENTION

[0002] For guidance, missiles can be equipped with a radar head to enable the acquisition of radar data from the perspective of the missile's radar head. The radar data can be analyzed and used, for example, to guide the missile or to control other objects. The radar head takes up a volume within the missile, usually in its head. A missile's propulsion system can be adapted to the dimensions of the radar head (volume, body, shape, arrangement, weight, etc.) in order to meet one or more requirements for the missile's performance. For precise guidance using radar data, the shape and structure of the missile, which includes an antenna array, can be important, for example.

[0003] One of the objects of the invention is to provide antenna arrangements which allow to increase the performance of the radar head or the missile, for example by reducing the complexity of the radar head with regard to an analysis of the acquired radar data, or with regard to a reduction of the volume occupied by the radar head.

[0004] DE 10 2020 001 153 A1 discloses a missile having a missile body and a radar sensor unit for detecting a target object, wherein the radar sensor unit comprises at least one longitudinally strip-shaped radar antenna which is mounted or integrated on a circumferential surface of the missile body such that the longitudinal direction of the at least one strip-shaped radar antenna is aligned in the direction of the missile longitudinal axis.

[0005] US 5,764,192 A discloses a conformal antenna array with a solid body and a field of view suitable for broadband precision direction finding on missile platforms. The antenna array comprises multiple sub-arrays with spiral antennas, with the sub-arrays covering specific areas within the desired field of view of the entire array. SUMMARY OF THE INVENTION

[0006] The invention is defined by the independent claims. The dependent claims define advantageous embodiments.

[0007] According to one aspect of the invention, an antenna assembly comprises a head of a body; and a plurality M of antenna elements arranged on the head of the body and outside the body. This increases volume within the body and reduces complexity of analyzing the acquired radar data. The plurality of antenna elements each comprises a housing, a tip, and an antenna, wherein the antenna has the shape of an elongated helix extending in a longitudinal direction of the antenna assembly. Polarization losses are thereby reduced.

[0008] According to a further development, a plurality of antenna elements are configured for transmitting and / or receiving circularly polarized electromagnetic radiation, in particular electromagnetic radiation for applications in radar technology. Transmission and / or reception is enabled, and the range of a radar is increased.

[0009] According to a further development, the length of the housing is not less than the length of the antenna. This allows the antenna to be arranged completely outside the head of the body.

[0010] According to a further development, the plurality of antenna elements is arranged symmetrically around an axis of symmetry of the antenna array. This enables a simplified analysis of the radar data.

[0011] According to a further development, the plurality M of antenna elements comprises a plurality E of antenna elements for receiving, a plurality S of antenna elements for transmitting and / or a plurality B of antenna elements for bidirectional transmitting and receiving, with E + S + B = M and E ≥ 0, S ≥ 0, B ≥ 0. This extends functionality and increases range or reduces complexity.

[0012] According to a further development, the plurality of antenna elements are arranged in a longitudinal direction of the antenna array at an edge of the head of the body. This can increase the radiation and / or reception power or enable an enlarged field of view.

[0013] According to a further development, the plurality of antenna elements each comprises a housing made of a first material, and the head of the body is made of a second material, wherein the first material and the second material are different. This optimizes the radiation and / or reception performance.

[0014] According to a further development, the plurality of antenna elements is configured to generate and / or receive radiation with the same left-handed or right-handed circular polarization. This reduces polarization losses.

[0015] According to one aspect of the invention, a missile comprises the antenna arrangement as described above. This enables a missile with an extended performance spectrum. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention is explained below with reference to the figures of the drawings. The figures show: Fig. 1 Front view of an exemplary antenna arrangement with antenna elements arranged symmetrically on a rotationally symmetric head of a body. Fig. 2 Side view of the exemplary antenna arrangement of Fig. 1. Fig. 3 Side view of a missile with an exemplary antenna arrangement.

[0017] The accompanying figures are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the noted advantages will be apparent upon review of the drawings. Elements of the drawings are not necessarily shown to scale. Directional terminology such as "top," "bottom," "left," "right," "above," "below," "horizontal," "vertical," "front," "rear," and similar designations are used for purposes of explanation only and are not intended to limit generality to specific embodiments shown in the figures.

[0018] In the figures, the same reference symbols generally designate identical or functionally identical components, unless otherwise stated. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0019] Fig. 1 shows a front view of an exemplary antenna arrangement 110 with antenna elements on a head of a body and outside the body, for example a missile 300 as in Fig. 3. The head of the body exhibits rotational symmetry without loss of generality (oBdA), meaning it can be circular when viewed from the front along a rotation axis x. The head of the body can also be elliptical, for example, when viewed from the front along the rotation axis x.

[0020] As in the Fig. 1, the antenna arrangement comprises a plurality M of antenna elements m with 1 ≤ m ≤ M. The plurality M can be an even or an odd integer, for example 4, 6, 8, 10, 12, 14, 16 or 18. The antenna elements can be identical or different. For example, S antenna elements can be configured for transmitting, E antenna elements for receiving and / or B antenna elements for bidirectionally transmitting and receiving electromagnetic radiation. The plurality M of antenna elements m can, for example, comprise 0, 2, 4, or 8 antenna elements for transmitting and 16, 14, 12, or 8 antenna elements for receiving, a total of 16 antenna elements each. The plurality M of antenna elements may also comprise 4 antenna elements for transmitting and 14 antenna elements for receiving, a total of 16 antenna elements, i.e. 2 antenna elements for transmitting and for receiving.Other combinations are also possible, in particular the case where all antenna elements are configured for transmitting and receiving, B = M. Antenna elements can differ at least in the direction of polarization and otherwise be identical.

[0021] The antenna elements for transmitting and the antenna elements for receiving can be arranged in successive groups on the body or the head of the body, e.g. 2 of the plurality S and 14 of the plurality E; or 4 of the plurality S and 12 of the plurality E; or 4 of the plurality S, 4 of the plurality E, 4 of the plurality S, 4 of the plurality E; or alternating 1 of the plurality S and 1 of the plurality E. The e.g. 16 antenna elements can also all be configured for transmitting and / or receiving. The configuration for transmitting can exclude the configuration for receiving and vice versa. In the case of a pure receiving arrangement, when all antenna elements are configured for receiving and no antenna element is configured for transmitting, the antenna arrangement can, for example, receive radar waves reflected from a target object that have been radiated by a transmitter onto the target object.

[0022] The antenna elements can be configured, in particular, to transmit and / or receive electromagnetic radiation for radar applications. The antenna elements can also be configured to transmit and / or receive in different frequency ranges.

[0023] The plurality M of antenna elements m can be rotationally symmetrical on a circle with radius r i , be arranged in a plane perpendicular to the rotation axis x of the head of, for example, the missile. The position of the antenna elements can be represented, for example, by a rotation angle φ(m) with 1 ≤ m ≤ M. The rotation angle φ(m) for the antenna element m can be given by the relationship φ(m) = (m - 1) × Δφ, with Δφ = 360° / M. For the plurality S and the plurality E, different rotation angles are possible. As in the Fig. 1, the radius r i smaller than a radius of the missile r a, if oBdA the case of concentric circles as the shape of the missile (outer, solid circle in Fig. 1) and the arrangement of the antenna elements (inner, dotted circle in Fig. 1). A radius d m / 2 of one, several, or all of the antenna elements m can be less than, equal to, or greater than the difference r a - r i the radii r a and r i The location of the antenna elements at the edge of the head of the body can, for example, enable an enlarged field of vision.

[0024] Fig. 2 shows a side view of an exemplary antenna arrangement 210 with antenna elements mounted on a head of an external body, for example a missile 300 as in Fig. 3. The head of the body has a hyperbolic shape when viewed laterally along a y-axis that is orthogonal to an x-axis. The head of the body can also have the shape of a circle or a triangle when viewed laterally along a y-axis.

[0025] As with reference to Fig. 1, the antenna arrangement comprises a plurality M of antenna elements m with 1 ≤ m ≤ M. To simplify the description, in Fig. 2 illustrates an example with 8 antenna elements. Alternative solutions, which are all consistent with the example in Fig. 2 are combinable, and vice versa, are related to the Fig. 1 described in detail.

[0026] Each of the antenna elements m may comprise a radome (derived from the English "radar dome") with a housing 211 and a tip 212. The housing may have a diameter (cf. d m in Fig. 1) in the range of 5 to 50 mm, preferably 10 to 20 mm, more preferably 12 to 15 mm. The housing 211 may have a length l mfrom 20 to 200 mm, preferably 50 to 120 mm, more preferably 70 to 100 mm. The radome can be arranged completely or at least partially outside the head of the body in order to increase a volume of available space within the head of the body. Each of the antenna elements m can further comprise an antenna 213. The antenna 213 can be a helical antenna configured to transmit and / or receive circularly polarized electromagnetic radiation. Other antennas extended in one direction, e.g., in the x-direction, and configured to transmit and / or receive circularly polarized electromagnetic radiation are also possible. The antenna 213 can, for example, form a helix around a cylinder, a cone, an ellipsoid, etc. The antenna 213 can have a directional characteristic 214 that is rotationally symmetric in a radiation direction.

[0027] The antenna 213 may be arranged in the radome. In particular, the length of the antenna 213 may be less than the length l m of the radome so that the antenna 213 in the radome can be arranged completely outside the head of the body.

[0028] The shape and material of each individual radome of an antenna 213 can be independent of the shape and material of the body head to enable optimal performance of the antenna 213. Losses and / or distortions during transmission and reception of a radar signal can thus be minimized. The shape and material of the respective radomes can also be adapted to the configuration of the antenna 213 (transmit, receive, transmit, and receive).

[0029] Due to the shape of the antenna elements and the dimensions of the respective antenna 213, the antenna elements can be mounted on the head of a missile 300 as in Fig. 3, so that space is freed up inside the head or the missile as a whole for, for example, a second instrument for guiding the missile. The second instrument can be an optical seeker, such as a seeker for detecting electromagnetic radiation in the infrared frequency range. Antenna arrangements according to the present disclosure can thus enable the use of multiple seekers to improve missile guidance while avoiding the need for a comprehensive change in the missile's shape.

[0030] Each antenna 213 can be configured to generate radiation with the same left- or right-handed circular polarization, regardless of the relative position and orientation of the antenna elements m. This allows a radiated and backscattered radar signal from each transmitting antenna to be received by each receiving antenna without polarization losses. Polarization losses refer to losses caused by different polarizations.

[0031] Fig. 3 shows a side view of a missile 300 with an antenna assembly 310 and a fuselage 320. The fuselage 320 may include a single-stage, two-stage, or multi-stage propulsion module. One or more of the propulsion stages of the propulsion module may be jettisonable. The antenna assembly 310 may surround one or more submodules. The antenna assembly 310 may, for example, surround an active or passive radar, one or more effectors, a controller, and / or means for wireless communication. In particular, an antenna assembly 310 may include a plurality of antenna elements, as described with reference to Fig. 1 and Fig. 2 described in detail.

[0032] In the foregoing detailed description, various features have been combined into one or more examples for clarity of illustration. It should be understood, however, that the above description is merely illustrative and not restrictive. It is intended to cover all alternatives, modifications, and equivalents of the various features and embodiments. Many other examples will be readily apparent to those skilled in the art based on their skill in the art in light of the above description.

[0033] The embodiments were chosen and described in order to best illustrate the principles underlying the invention and their possible practical applications. This will enable those skilled in the art to optimally modify and utilize the invention and its various embodiments with respect to the intended purpose. In the claims and the description, the terms "including" and "having" are used as neutral language terms for the corresponding term "comprising." Furthermore, the use of the terms "a," "an," and "an" is not intended to exclude a plurality of features and components described in this way. LIST OF REFERENCE SYMBOLS x10 antenna arrangement (x = 1, 2 or 3) 211 Housing of a radome of an antenna element m 212 Tip of a radome of an antenna element m 213 Antenna of an antenna element m 214 Directional characteristic of an antenna element m 300 missiles 320 Fuselage of the missile 300

Claims

[1] Antenna arrangement (110, 210, 310), comprising: a head of a body; and a plurality M of antenna elements (m) arranged on the head (110) of the body and outside the body; wherein the plurality M of antenna elements (m) each comprise a housing (211), a tip (212), and an antenna (213), the antenna (213) having the shape of an elongated helix extending in a longitudinal direction of the antenna arrangement (110, 210, 310). [2] Antenna arrangement (110, 210, 310) according to claim 1, wherein the plurality M of antenna elements (m) is configured to transmit and / or receive circularly polarized electromagnetic radiation, in particular electromagnetic radiation for applications in radar technology. [3] Antenna arrangement (110, 210, 310) according to claim 1, wherein a length l m of the housing (211) is not smaller than a length of the antenna (213). [4] Antenna arrangement (110, 210, 310) according to any one of claims 1 to 3, wherein the plurality M of antenna elements (m) are arranged symmetrically about an axis of symmetry (x) of the antenna arrangement (110, 210, 310). [5] Antenna arrangement (110, 210, 310) according to any one of claims 1 to 4, wherein the plurality M of antenna elements (m) comprises a plurality E of antenna elements for receiving, a plurality S of antenna elements for transmitting and / or a plurality B of antenna elements for bidirectional transmitting and receiving, with E + S + B = M and E ≥ 0, S ≥ 0, B ≥ 0. [6] Antenna assembly (110, 210, 310) according to any one of claims 1 to 5, wherein the plurality M of antenna elements (m) are arranged in a longitudinal direction of the antenna assembly (110, 210, 310) at an edge of the head of the body. [7] Antenna arrangement (110, 210, 310) according to claim 1, wherein the plurality M of antenna elements (m) each comprises a housing (211) made of a first material and the head of the body is made of a second material, the first material and the second material being different. [8] Antenna arrangement (110, 210, 310) according to any one of claims 1 to 7, wherein the plurality M of antenna elements (m) are configured to generate and / or receive radiation with the same left-handed or right-handed circular polarization. [9] Missile (300), comprising: the antenna assembly (110, 210, 310) of any one of claims 1 to 8, wherein the body is the missile (300).

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