WIDEBAND HORIZONTALLY POLARIZED ANTENNA

Abstract

The disclosure relates to an antenna arrangement, including an antenna mounted inside a radome. The antenna arrangement further includes a mounting arrangement arranged to mount the antenna arrangement to an antenna platform. The antenna is a tapered slot antenna, the radome has an aerodynamic shape, and the mounting arrangement includes two antenna fastening means and an antenna radio frequency connector arranged to interact with corresponding antenna platform fastening means and an antenna platform radio frequency connector arranged on the antenna platform.

Claims

1. An antenna arrangement, comprising an antenna mounted inside a radome, a mounting arrangement attached to the radome arranged to mount the antenna arrangement to an antenna platform, wherein: the antenna is a tapered slot antenna, the radome has an aerodynamic shape, and the mounting arrangement comprises two antenna fastening means and an antenna radio frequency connector arranged to interact with corresponding antenna platform fastening means and an antenna platform radio frequency connector arranged on the antenna platform.

2. The antenna arrangement according to claim 1, wherein the tapered slot antenna is one of an exponential tapered slot antenna, a linear tapered slot antenna, a continuous-width slot antenna, dual exponentially tapered slot antenna, a stepped slot antenna, a step-constant tapered slot antenna, a tangential tapered slot antenna, a parabolic tapered slot antenna, a linear-constant tapered slot antenna, an exponential-constant tapered slot antenna or a broken-linear tapered slot antenna.

3. The antenna arrangement according to claim 1, wherein the material of the radome is at least one of plastic, composite glass, fibreglass or quartz.

4. The antenna arrangement according to claim 1, wherein the antenna platform is an airborne vehicle, wherein the antenna arrangement is arranged on an essentially vertical surface of the airborne vehicle such that the antenna arrangement is arranged to receive and transmit radio frequency signals that are horizontally polarized and propagates perpendicular to the direction the antenna platform is moving.

5. The antenna arrangement according claim 1, wherein the antenna platform is a manned or unmanned land vehicle, wherein the antenna arrangement is arranged on an essentially vertical surface of the manned or unmanned land vehicle such that the antenna arrangement is arranged to receive and transmit radio frequency signals that are horizontally polarized and propagates perpendicular to the direction the antenna platform is moving.

6. The antenna arrangement according to claim 1, wherein the antenna platform is a manned or unmanned surface vehicle, wherein the antenna arrangement is arranged on an essentially vertical surface of the manned or unmanned surface vehicle such that the antenna arrangement is arranged to receive and transmit radio frequency signals that are horizontally polarized and propagates perpendicular to the direction the antenna platform is moving.

7. The antenna arrangement according claim 1, wherein the antenna radio frequency connectors and platform radio frequency connectors are SubMiniature version A co-axial connectors.

8. An array antenna comprising a multitude of antenna arrangements according to claim 1, where the antenna arrangements are arranged essentially along the same linear extension of an antenna platform.

9. A method for receiving and transmitting radio-frequency signals with horizontal polarization and propagation perpendicular to a direction in which an antenna platform is moving, wherein the method comprises: providing an antenna arrangement by mounting a tapered slot antenna inside an aerodynamically shaped radome, further providing the antenna arrangement with a mounting arrangement comprising two antenna fastening means and one antenna radio frequency connector, arranging, on a vertical surface of an antenna platform, an antenna platform fastening means and an antenna platform radio frequency connector arranged to interact with the antenna fastening means and an antenna radio frequency connector, and attaching the antenna arrangement to the antenna platform and connecting the antenna arrangement to a control system through the antenna radio frequency connector and the antenna platform radio frequency connector.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 schematically shows a prior art antenna arrangement,

[0044] FIG. 2 schematically shows an antenna arrangement according to the disclosure,

[0045] FIG. 3a schematically shows an antenna platform in the form of an airplane with an antenna arrangement according to the disclosure,

[0046] FIG. 3b schematically shows an antenna platform in the form of an airplane with an array antenna according to the disclosure,

[0047] FIG. 4 schematically shows an antenna platform in the form of an airplane travelling in a racetrack flight pattern,

[0048] FIG. 5 schematically shows an antenna platform in the form of a ground vehicle with an antenna arrangement according to the disclosure,

[0049] FIG. 6 schematically shows an antenna platform in the form of a surface vehicle with an antenna arrangement according to the disclosure.

DETAILED DESCRIPTION

[0050] In the figures, an antenna is defined by a coordinate system x, y, z (lowercase), where the x-axis is the longitudinal axis, the y-axis is the transverse axis and the z-axis is the vertical axis. An antenna platform is defined by a coordinate system X, Y, Z (uppercase), where the X-axis is the vertical axis, the Y-axis is the transverse axis and the Z-axis is the longitudinal axis.

[0051] FIG. 1 schematically shows a prior art blade antenna arrangement 101. The prior art antenna arrangement 101 comprises a shaped monopole antenna 102 placed inside a radome 103. The radome is normally opaque for optical frequencies but not for RF frequencies and its borders are therefore outlined with dash-double-dot lines. The blade antenna 102 is mounted on a ground plane 104 and is arranged to be mechanically connectable by means of two antenna fastening means 105 and electronically connectable by means of an antenna radio frequency connector 106 to an antenna platform such as an aircraft (not shown).

[0052] The prior art antenna arrangement 101 is a common aircraft-mounted antenna for VHF and UHF radio frequencies and is described in the background. Advantages of a blade antenna 102 are the ease of installation exemplified by the two screws acting as antenna fastening means 105 shown in FIG. 1, and the aerodynamic profile of the radome 103. However, the blade antenna 102 does not provide horizontal polarization or propagation perpendicular to the direction an antenna platform onto which the antenna arrangement is attached is moving. For simplicity, the antenna feed and other known details required for the functioning of the antenna are not shown.

[0053] FIG. 2 schematically shows an antenna arrangement 1 according to the disclosure. In the antenna arrangement 1 in FIG. 2, the blade antenna 102 of FIG. 1 has been replaced by a tapered slot antenna 2 mounted on a ground plane 4. Further, a radome 3 has an aerodynamic shape. A mounting arrangement comprises two antenna fastening means 5 and an antenna radio frequency connector 6 arranged to interact with corresponding antenna platform fastening means (not shown) and an antenna platform radio frequency connector (not shown) arranged on an antenna platform (not shown).

[0054] Since the tapered slot antenna 2 is an end-fire antenna, the radiation pattern will have a maximum in the z-direction, and be polarized along the y-axis. The bandwidth and realized gain or radiation efficiency of the tapered slot antenna 2 are both greater than those of the blade antenna leading to a number of advantages over the prior art antenna arrangement 1 of FIG. 1.

[0055] A number of variations of tapered slot antennas 2 can be used with the antenna arrangement 1 according to the disclosure depending on desired characteristics. For simplicity, the antenna feed and other known details required for the functioning of the antenna are not shown.

[0056] FIG. 3a schematically shows an antenna platform 7a in the form of an airplane with an antenna arrangement 1 according to the disclosure. FIG. 3a shows an example placement of an antenna arrangement 1 on an aircraft in order to utilize the advantages provided by the antenna arrangement 1, i.e. a radiation pattern in the z-direction of the tapered slot antenna 2 with polarization along the y-axis.

[0057] FIG. 3b schematically shows an antenna platform 7a in the form of an airplane with an array antenna 8 according to the disclosure. Multiple antenna arrangements 1 can be installed along a length of an aircraft to form an array antenna 8 according to FIG. 3b. An array antenna 8 can be used for direction finding (DF) in electronic surveillance (ES), and for achieving high gain for electronic attack (EA).

[0058] FIG. 4 schematically shows an antenna platform 7a in the form of an airplane travelling in a racetrack flight pattern. The antenna arrangement 1 and/or array antenna 8 is beneficial for electronic warfare (EW) and signals intelligence aircrafts. Antenna arrangements 1 satisfying the criteria 1-5 above are of interest for race-track flight, as they are used for both stand-off jamming and surveillance. In FIG. 4, a number of threats 9 are displayed as being in range of the antenna arrangement 1 and/or array antenna 8 and stand-off jamming and/or surveillance can be performed on the threats 9 as indicated by the arrow. The arrow symbolizes signals reception and transmission.

[0059] FIG. 5 schematically shows an antenna platform 7b in the form of a ground vehicle with an antenna arrangement 1 according to the disclosure. Similar to the airborne antenna platform 7a of FIG. 4, a land based antenna platform 7b can benefit from having one or more antenna arrangements 1 installed as described above. Although only one antenna arrangement is shown, it is to be understood that the antenna platform 7b may alternatively comprise a linear antenna array 8 according to FIG. 3b.

[0060] FIG. 6 schematically shows an antenna platform 7c in the form of a surface vehicle with an antenna arrangement 1 according to the disclosure. Similar to the airborne antenna platform 7a of FIG. 4 and the land based antenna platform 7b of FIG. 5, a surface vehicle can benefit from having one or more antenna arrangements 1 installed as described above. Although only one antenna arrangement is shown, it is to be understood that the antenna platform 7c may alternatively comprise a linear antenna array 8 according to FIG. 3b.

[0061] In other words, the antenna platforms 7a, 7b, 7c are suitable for implementation of a method for receiving and transmitting radio-frequency signals with horizontal polarization and propagation perpendicular to a direction an antenna platform (7a, 7b, 7c) is moving. The method comprises: [0062] providing an antenna arrangement 1 by mounting a tapered slot antenna 2 inside an aerodynamically shaped radome 3, [0063] further providing the antenna arrangement 1 with a mounting arrangement comprising two antenna fastening means 5 and one antenna radio frequency connector 6, [0064] arranging, on a vertical surface of an antenna platform 7a, 7b, 7c, antenna platform 7a, 7b, 7c fastening means and antenna platform radio frequency connector arranged to interact with the antenna fastening means 5 and antenna radio frequency connector 6, [0065] attaching the antenna arrangement 1 to the antenna platform 7a, 7b, 7c and connecting the antenna arrangement 1 to a control system through the antenna radio frequency connector 6 and the antenna platform radio frequency connector.

[0066] The control system is an RF system, for instance an electronic warfare system and/or a radar system.

[0067] In the context of the disclosure, aerodynamic shape means that the shape of the radome 3 reduces drag from passing through the air compared to a shape that is not aerodynamic. Examples of radomes 3 with aerodynamic shapes can be seen in U.S. Pat. No. 4,072,952 A and are available from a number of blade antenna manufacturers.

[0068] The tapered slot antenna 2 can be printed or etched on a substrate with microstrip feed, printed or etched on a dielectric substrate with stripline feed, made of one layer of metal with microstrip 5 feed, printed or etched on a substrate with differential feed, made of one layer of metal with differential feed. The stepped slot antenna is also known as notch element.

[0069] As will be realised, the invention is capable of modification in various obvious respects, all without departing from the scope of the appended claims. Accordingly, the drawings and the description are to be regarded as illustrative in nature, and not restrictive.