EP2744044A1 - Verbesserungen bei Antennen - Google Patents

Verbesserungen bei Antennen Download PDF

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Publication number
EP2744044A1
EP2744044A1 EP12275204.1A EP12275204A EP2744044A1 EP 2744044 A1 EP2744044 A1 EP 2744044A1 EP 12275204 A EP12275204 A EP 12275204A EP 2744044 A1 EP2744044 A1 EP 2744044A1
Authority
EP
European Patent Office
Prior art keywords
sub
array
stripline
antenna
support structure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP12275204.1A
Other languages
English (en)
French (fr)
Inventor
designation of the inventor has not yet been filed The
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems PLC
Original Assignee
BAE Systems PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BAE Systems PLC filed Critical BAE Systems PLC
Priority to EP12275204.1A priority Critical patent/EP2744044A1/de
Priority to US14/651,892 priority patent/US9627776B2/en
Priority to BR112015013853-5A priority patent/BR112015013853B1/pt
Priority to ES13806040T priority patent/ES2698126T3/es
Priority to AU2013357017A priority patent/AU2013357017B2/en
Priority to PL13806040T priority patent/PL2932562T3/pl
Priority to EP13806040.5A priority patent/EP2932562B1/de
Priority to PCT/GB2013/053259 priority patent/WO2014091228A1/en
Publication of EP2744044A1 publication Critical patent/EP2744044A1/de
Priority to CL2015001633A priority patent/CL2015001633A1/es
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/0006—Particular feeding systems
    • H01Q21/0075—Stripline fed arrays
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/0087—Apparatus or processes specially adapted for manufacturing antenna arrays

Definitions

  • the present invention relates to the field of antennas, particularly antenna for use in Radar systems. It finds particular, but not exclusive utility in the field of marine Radar systems i.e. those installed on ships.
  • Most or many ships are equipped with at least one Radar system, used for navigation and/or other purposes.
  • military vessels are frequently equipped with a weapons system Radar which is provided to locate, identify and possibly track possible threats.
  • the complexity and functionality of such a weapons system Radar is far greater than that of a relatively simple navigational Radar system.
  • the Radar antenna rotates to sweep signals across the location and is affixed to an upper portion of a high mast on the vessel. It is desirable to position the antenna as high as possible to give optimal range coverage and to avoid any other parts of the vessel from obscuring the transmit or receive Radar signal.
  • the antenna typically has a mass of several hundred kilograms.
  • the mass of the system is due to prior art antennas incorporating a good deal of the Radio Frequency (RF) equipment within the antenna housing.
  • RF equipment typically includes one or more of transmitters, receivers, duplexers, filters and associated processing equipment.
  • the signals from the RF equipment are passed to digital processing systems, using one or more complex rotating joints which allow electrical continuity between the rotating antenna housing and the connected circuits.
  • Embodiments of the present invention aim to address these and other problems with prior art Radar antennas, whether mentioned herein or not.
  • an antenna sub-array for use in an antenna array comprising a plurality of such sub-arrays, comprising: a stripline for signal distribution, the stripline defining a plurality of signal pathways from a common feed point to a plurality of radiating elements, wherein the stripline is housed in a first support structure located a distance away from a first surface of a ground plane structure.
  • the first support structure comprises a foam material having predefined dielectric properties.
  • the predefined dielectric properties include having a dielectric constant substantially equal to that of air.
  • the stripline is located in a channel in the first support structure and held in position above the first surface of the ground plane structure by a button formed from the same material as the first support structure.
  • affixed to a second surface of the ground plane structure is a second support structure.
  • first and second support structures are different materials.
  • the stripline and the radiating elements are integrally formed.
  • the first support structure comprises a plurality of channels arranged to receive a cooling fluid for cooling the stripline and radiating elements.
  • an antenna array comprising a plurality of sub-arrays according to the first aspect.
  • a method of manufacturing an antenna array comprising the steps of: providing a plurality of sub-arrays, each according to the first aspect; assembling the plurality of sub-arrays in a layered arrangement and securing each sub-array to a neighbouring sub-array with an adhesive substance; curing said adhesive to form a unitary antenna array.
  • a method of cooling an antenna sub-array comprising the steps of: providing a channel in a portion of the sub-array, said channel housing at least some Radio Frequency components; and forcing a cooling fluid into the channel via a first aperture, such that the cooling fluid passes through the channel and is exhausted at a second aperture.
  • the first aperture is proximal to a Radio Frequency connector of the sub-array.
  • the second aperture is proximal to one or more of the plurality of radiating elements.
  • the channel is provided in the first support structure, which houses the stripline.
  • Embodiments of the present invention allow an antenna array, for use with a Radar system, to be constructed from a plurality of individual sub-arrays.
  • the sub arrays are substantially identical. This provides a great deal of design freedom, and allows antenna arrays having different functional properties to be created, starting from a single building block, namely the sub-array.
  • the sub-array is arranged to be lightweight and, as such, is constructed, as far as possible, from lightweight foam materials, which are used to support and house the feed and radiating components, which carry and transmit the RF signals, respectively.
  • stripline techniques are often used to carry and distribute the signals from transmitters and/or receivers to individual radiating elements, which are arranged to co-operate to produce a desired antenna performance. Details of the stripline construction and its housing will follow shortly.
  • Figure 1a shows a rear perspective view of an antenna sub-array 1 according to an embodiment of the present invention.
  • the sub-array in this embodiment is formed to have a substantially rectangular profile in plan view. In terms of its dimensions, it is significantly larger in width and depth than height, although other configurations are possible where this may not be the case.
  • an RF connector 2 which forms a common feed point for connection of the sub-array 1 to the RF equipment (not shown).
  • the RF connector may be an N-type coaxial connector or any other suitable form of connector.
  • a plurality of individual radiating elements 3 On the front surface, as shown in Figure 1b , there is provided a plurality of individual radiating elements 3. In the present embodiment, these take the form of identical dipole elements. In alternative embodiments, the individual radiating elements may not be identical and may not be dipole elements, but different forms of antenna.
  • the dipole elements 3 are integrally formed with the stripline, meaning that the feed structure and the radiating structure are part of the same physical entity, having been milled from the same sheet of material. This has advantages in ease of manufacture and helps to ensure reliable antenna performance.
  • the individual radiating elements may be connected to the stripline feed structure by respective individual connectors.
  • Figure 2 shows a typical stripline 7 layout.
  • the stripline is milled from sheet aluminium to precise tolerances and, as far as is practicable, from a single sheet of material.
  • the path length of any particular branch is calculated to achieve a particular phase relationship between each respective path. For instance, in most cases, it will be desired to ensure that each individual path length is identical and so certain of the individual branches may meander or deviate to achieve this. The exact nature of this meandering not shown here, and will depend on the specification of the antenna sub-array.
  • the stripline 7 is accommodated as shown in Figure 3 which shows a cross-sectional view through a sub-array 1.
  • a ground plane 4 This is formed from aluminium1200 foil, 0.2mm thick which is secured to a layer of structural foam 5, by means of a lightweight adhesive film (such as SA70/100g adhesive film).
  • the structural foam 5 provides strength and form to the sub-array. It is chosen to have specified mechanical properties and to be as lightweight as possible, while still providing the required strength and structure.
  • a suitable lightweight structural foam material is ROHACELL 31 IG, a polymethacrylimide foam, available from Evonik industries ( www.evonik.com ).
  • a further ground plane 4 identical to the one secured to the lower surface of the structural foam 5.
  • dielectric foam 6 Secured to the upper ground plane 4 is a layer of dielectric foam 6. This is so-called as this layer of foam has specific dielectric properties, which have an influence on the properties of the stripline 7. Specifically, the dielectric foam 6 is selected to have a dielectric constant as near as possible to that of free air.
  • a suitable dielectric foam is ROHACELL 31 HF, a polymethacrylimide foam, also available from Evonik Industries. In other embodiments, the dielectric foam may be selected to have a dielectric constant which is significantly different to that of free air to achieve different transmission effects.
  • the same adhesive film which is used to secure the lower ground plane 4 to the structural foam 5, is used to secure the other parts of the sub-array together i.e. it is located between structural foam 5 an upper ground plane 4, and also between upper ground plane 4 and dielectric foam 6. It is also used to secure each individual sub array to its neighbouring sub-array when the complete array is constructed, as will be described shortly.
  • the dielectric foam 6 has channels cut into it which conform generally to the arrangement of the stripline 7, such that the stripline 7 can be accommodated in the channels and within the thickness of the dielectric foam 6.
  • a channel in the dielectric foam can be seen, in which is situated the stripline 7. It is supported above the lower ground plane 4 by a button 8 of dielectric foam.
  • button 8 positioned above the lower button so that the stripline 7 is effectively sandwiched into position and so can maintain a constant distance between the upper and lower ground planes 4, for its entire length. This is important in ensuring proper operation of the stripline in feeding RF signals to the antenna elements 3.
  • the antenna elements 3 are arranged to protrude from beyond the front surface of the sub-array 1.
  • a plurality of individual sub-arrays 1 are coupled together, as shown in Figure 4 .
  • the lower ground plane 4 of a first sub-array when placed atop another sub-array, completes the stripline circuit, by enclosing the stripline 7 between two ground planes.
  • a ground plane 4 is affixed atop the dielectric foam 6.
  • a further layer of structural foam 5 may be provided at the very top of the array to protect the stripline 7 disposed within the uppermost sub-array.
  • the curing process involves placing the complete array assembly in an oven at 80°C.
  • Thermocouples may be provided at various points of the array to ensure that the core temperature is maintained at the correct level. Then the array is allowed to cool, during which time it is found that the height of the array assembly reduces by a few millimetres, typically. However, after about 2 weeks, the height is recovered.
  • the selected adhesive film having 100g per square metre weight profile ensures that the amount of adhesive in the assembly is a known controlled quantity and allows the stripline and ground plane 4 to interact correctly.
  • the number of sub-arrays 1 required to form the antenna array 10 is determined by the performance requirements of the finished antenna array. Using beam-forming techniques, which are know in the field of Radar design, the beams formed by the respective sub-arrays 1 can be made to co-operate to give a desired performance. If a lesser degree of performance is required, then fewer sub-arrays can be included in the antenna array. Therefore, the modular design approach employed herein lends itself well to flexible design methodologies, where overall system requirements can be altered relatively straightforwardly.
  • Figure 5 shows how the channels formed in the dielectric foam permit a cooling to be propelled through said channels for the purposes of cooling the stripline and radiating elements (not shown in Figure 5 , for clarity).
  • Cooled air is the preferred cooling fluid and it is injected into the sub array in the vicinity of the connector 2.
  • the cooled air flows through the channels in which the stripline 7 is housed, and exits the sub-array in the vicinity of the radiating elements 3, having cooled the parts it has contacted along its way.
  • the now warmer air is expelled from the antenna housing in a continuous flow.
  • buttons 8 which support the stripline and maintain its position between the upper and lower ground planes are dimensioned to ensure that air can pass through the channels relatively unimpeded. Given the branching nature of the channels, cooling fluid injected at a common point, flows along each channel and cools all parts of the antenna array. The cooling fluid essentially follows the same path as the stripline 7.
  • antenna arrays of significantly lower mass than prior art antennas can be constructed. Furthermore, by making use of a plurality of identical sub-arrays, different overall antenna characteristics and specification can be achieved, without re-designing the entire antenna. Instead, the desired performance may be achieved by use of an appropriate number of sub-arrays.
  • Embodiments of the present invention are able to meet stringent weight requirements by use of composite manufacturing techniques, which are believed not to have been used in antenna manufacture before.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
EP12275204.1A 2012-12-14 2012-12-14 Verbesserungen bei Antennen Ceased EP2744044A1 (de)

Priority Applications (9)

Application Number Priority Date Filing Date Title
EP12275204.1A EP2744044A1 (de) 2012-12-14 2012-12-14 Verbesserungen bei Antennen
US14/651,892 US9627776B2 (en) 2012-12-14 2013-12-11 Antennas
BR112015013853-5A BR112015013853B1 (pt) 2012-12-14 2013-12-11 Subarranjo de antena, arranjo de antena, método de fabricação de um arranjo de antena, e, método de resfriamento de um subarranjo de antena
ES13806040T ES2698126T3 (es) 2012-12-14 2013-12-11 Mejoras en antenas
AU2013357017A AU2013357017B2 (en) 2012-12-14 2013-12-11 Improvements in antennas
PL13806040T PL2932562T3 (pl) 2012-12-14 2013-12-11 Usprawnienia w antenach
EP13806040.5A EP2932562B1 (de) 2012-12-14 2013-12-11 Verbesserungen bei antennen
PCT/GB2013/053259 WO2014091228A1 (en) 2012-12-14 2013-12-11 Improvements in antennas
CL2015001633A CL2015001633A1 (es) 2012-12-14 2015-06-11 Mejoramiento en antenas

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP12275204.1A EP2744044A1 (de) 2012-12-14 2012-12-14 Verbesserungen bei Antennen

Publications (1)

Publication Number Publication Date
EP2744044A1 true EP2744044A1 (de) 2014-06-18

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP12275204.1A Ceased EP2744044A1 (de) 2012-12-14 2012-12-14 Verbesserungen bei Antennen

Country Status (1)

Country Link
EP (1) EP2744044A1 (de)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2171257A (en) * 1984-12-20 1986-08-20 Marconi Co Ltd A dipole array
US6239764B1 (en) * 1998-06-09 2001-05-29 Samsung Electronics Co., Ltd. Wideband microstrip dipole antenna array and method for forming such array
US20040021613A1 (en) * 2000-09-29 2004-02-05 Aleksandar Nesic Dipole feed arrangement for corner feflector antenna
US20070279303A1 (en) * 2004-09-13 2007-12-06 Robert Bosch Gmbh Antenna Structure for Series-Fed Planar Antenna Elements
US20080106482A1 (en) * 2006-11-08 2008-05-08 Alan Cherrette Electronically scanned hemispheric antenna

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2171257A (en) * 1984-12-20 1986-08-20 Marconi Co Ltd A dipole array
US6239764B1 (en) * 1998-06-09 2001-05-29 Samsung Electronics Co., Ltd. Wideband microstrip dipole antenna array and method for forming such array
US20040021613A1 (en) * 2000-09-29 2004-02-05 Aleksandar Nesic Dipole feed arrangement for corner feflector antenna
US20070279303A1 (en) * 2004-09-13 2007-12-06 Robert Bosch Gmbh Antenna Structure for Series-Fed Planar Antenna Elements
US20080106482A1 (en) * 2006-11-08 2008-05-08 Alan Cherrette Electronically scanned hemispheric antenna

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