Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
  • H01Q9/045—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with particular feeding means
  • H01Q9/0457—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with particular feeding means electromagnetically coupled to the feed line
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/12—Supports; Mounting means
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
  • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
  • H01Q1/246—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for base stations
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/52—Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
  • H01Q13/02—Waveguide horns
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
  • H01Q19/005—Patch antenna using one or more coplanar parasitic elements
• • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q21/00—Antenna arrays or systems
  • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
  • H01Q21/08—Arrays of individually energised antenna units similarly polarised and spaced apart the units being spaced along or adjacent to a rectilinear path
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q23/00—Antennas with active circuits or circuit elements integrated within them or attached to them
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
  • H01Q9/0414—Substantially flat resonant element parallel to ground plane, e.g. patch antenna in a stacked or folded configuration

Definitions

• the present invention relates to an antenna assembly and a method of mounting such an assembly.
• the antenna assembly comprises a reflector m the form of a rigid metal sheet and a printed circuit board, PCB, having a ground plane layer and at least one radiating element. More particularly, the antenna assembly is of tiie kind stated m the preamble of claim 1.
• the radiating antenna elements may be formed m a planar portion of the reflector itself, m which case the PCB is provided with a conductive layer on one side only (and the reflector serves as a ground plane on the front side) , or on the PCB, m which case the PCB normally has two conductive layers, one on each side thereof .
• the ground plane layer of the PCB which is located on the front side of the reflector, has to be RF-coupled to the reflector, whicn leads to structural complications.
• the PCB is held m place m longitudinal side walls being unitary with the reflector and extending tnerealong so as to hold the PCB in front of the reflector. This structure will generally reduce the possibilities of shaping the reflector in an optimal way for achieving a desired radiation pattern.
• the main object of the invention is to provide an antenna assembly of the kind discussed above which permits the production of a well-defined structure with high precision of the critical dimensions of the assembly and which enables an easy and inexpensive mounting method.
• a ground plane layer is located on the front side of the PCB, and each radiating element thereon is confined within a corresponding opening m a planar portion of the reflector. Peripheral portions of the ground plane layer on the PCB are held m close proximity to the reflector around the contour of each opening so as to provide a capacitive or conductive coupling therebetween.
• the radiating elements on the PCB can be formed by known techniques, e.g. by etching so as to provide precise dimensions of these elements.
• the reflector will form an extension, both geometrically and electrically, of the ground plane on the front side of the PCB.
• the reflector portions surrounding each opening is positioned exactly m direct contact with or at a well-defined distance (defined by the thickness of a thin intermediary layer such as an adhesive tape) from the peripheral portions of the ground plane on the front side of the PCB. Therefore, the radiating elements and the adjoining portions of the reflector can be configured with great precision and with a shape adapted to the desired radiation pattern.
• Fig. 1 illustrates schematically, m an exploded, perspective view, various parts of the antenna assembly before being mounted on a fixture at the bottom of the figure;
• Fig. 2 shows a cross-section through a first embodiment of the antenna assembly according to the invention
• Fig. 3 shows, m a cross-sectional partial view, a modified version of the first embodiment shown m figs. 1 and 2 ;
• Fig. 4 shows, m a perspective, partially cross-sectional view, a second embodiment of the antenna assembly according to the invention
• Figs. 5 and 6 show, m cross-sectional views, two modified versions of the second embodiment shown m fig. 4;
• Figs. 7-10 show various embodiments of the radiating elements on the front side of the PCB.
• a fixture F for mounting an antenna assembly 1 the major parts 10,20,30,40 of which are shown above the fixture F.
• the antenna assmbly is suitable for transmitting and/or receiving RF electromagnetic waves, e.g. at a base station m a cellular mobile telephone system.
• the antenna assembly 1 comprises a relatively flexible printed circuit board 10 (PCB) of a dielectric material with electrically conductive layers on both sides thereof, a reflector body 20 of a rigid metal sheet having a central, substantially planar portion 21, a number of radiating patches 30 of an electrically conductive material, and an external casing or radome 40 of a dielectric material.
• PCB printed circuit board
• the basic parts 10,20 and 40 are elongated m a longitudinal direction, as will be apparent from fig. 1, and contain a linear row of antenna elements .
• the PCB 10 has on its front side (the upper side m fig.l) a thin metal coating constituting a ground plane layer 11.
• This ground plane layer 11 is provided with a number of apertures 12 m the form of mutually crossing slots 12a, 12b serving as radiating elements m order to couple high frequency electromagnetic power between a feed network on the rear side of the PCB and the radiating patches 30.
• the general structure of such an antenna assembly is described m more detail in the above-mentioned document WO 97/43977.
• the feed network on the rear side of the PCB includes microst ⁇ ps 13 and associated feed elements (not shown) m registry with the respective radiating aperture 12, e.g. of the kind described m the document W098/33234 (Allgon) .
• two orthogonally polarised microwave carriers, with mobile telephone signals superposed thereon are transferred between each pair of feed elements and the respective radiating patch 30.
• a number of shielding boxes 14 of a metal material are secured to the PCB behind each radiating aperture 12.
• the boxes 14 are secured mechanically and electrically to the upper ground layer 11 by means of closely distributed soldered pins 15.
• the elongated PCB, with the ground plane layer 11 and the radiating apertures 12 on the front side, and with the microstrips 13 and the shielding boxes 14 on the rear side, is first made as a unit 10, which is positioned onto the fixture F with the boxes 14 fitting into corresponding recesses R m the fixture. Then, m accordance with the present invention, the reflector 20 is secured to the PCB by securing the peripheral portions of the ground plane layer 11, outside the respective region containing the apertures 12 (or corresponding radiating elements) , to the substantially flat or planar portion 21 of the reflector. For this purpose, and in accordance with the present invention, the reflector 20 is provided with a number of openings 22 in the planar portion 21.
• Each such opening is symmetric in relation to the centre of the associated radiating aperture 12. It is important that the reflector is securely fastened to the PCB along the contour of the respective opening 22, i.e. along the edges 22a of the openings 22 which are generally rectangular or square in the embodiment shown in figs . 1 and 2.
• the reflector 20 is secured to the PCB by means of an adhesive tape.
• an adhesive tape having an adhesive layer on each side thereof, is applied to lower side of the planar portion 21 of the reflector body 20.
• the adhesive tape should cover the regions surrounding the openings 22, but not the openings as such. Therefore, the adhesive tape is preferably applied before the openings are punched out of the reflector body (and out of the tape) .
• the reflector body 20, with the adhesive tape 16 (fig.2), is lowered onto the PCB, so that the planar portion 21 is fitted and securely fastened to the PCB.
• the patches are mounted at a distance from the reflector, e.g. by means of plastic legs with snap fittings, and the radome 40 is finally fitted onto the reflector to complete the assembly.
• the radome 40 is finally fitted onto the reflector to complete the assembly.
• mechanical and electrical parts which have to be fitted into the total structure. For clarity, these parts are not shown m the drawings .
• the reflector body 20 is secured m a well-defined position m relation to the ground plane layer 11, so that a good electrical coupling is achieved, m this case m the form of a capacitive coupling. Also, it is important to establish a well-defined mechanical bond, so that the radiation parameters are obtained as desired and calculated m advance.
• the radiating aperture 12 is formed with high precision, e.g. by etching of the conductive layer 11, and the planar portion 21 of the reflector will form a well-defined mechanical and electrical extension of the ground plane layer 11.
• the opening 22 should circumscribe the radiating aperture 12 and leave that region of the ground plane totally free, so that the electromagnetic radiation can propagate freely therethrough.
• the other portions of the reflector 20 may be configured at will m order to obtain the desired radiation pattern.
• the reflector 20 is provided with side portions 23, which extend generally obliquely backwards towards the rear of the assembly.
• the reflector may alternatively be secured to the edge portions of the PCB by means of mechanical fasteners 16a, such as screw fasteners or rivets (not shown) . It is also possible to make soldered connections by applying a soldering paste and processing the assembly m an oven. In these alternative fastening methods, there will be a direct electrical contact between the metal material of the reflector 20 (the planar portion 21 therof) and the ground plane layer 11 (as illustrated m fig. 3) .
• fig 4 there is shown a second embodiment of the antenna assembly 1', where the reflector 20' is formed as a closed housing with a bottom wall 20 'a, outer side walls 20 'b, upper corrugated wall portions 20'c (serving as cooling flanges), inner longitudinal side walls 20 'd, which diverge away from each other obliquely upwards (towards the front side of the assembly, m the forward direction of the radiated power) , a central, horizontal or planar wall portion 20 'e and inner wall portions 20' f defining a shielding box.
• the reflector 20' is formed as a closed housing with a bottom wall 20 'a, outer side walls 20 'b, upper corrugated wall portions 20'c (serving as cooling flanges), inner longitudinal side walls 20 'd, which diverge away from each other obliquely upwards (towards the front side of the assembly, m the forward direction of the radiated power) , a central, horizontal or planar wall portion
• the inner wall portions 20' f divide the PCB 10' into a central portion and two longitudinal outer portions .
• These three portions of the PCB can be provided with mutually separated circuitry, e.g. transceiver circuitry included in a transmitter/receiver forming parts of a cellular base station in a mobile telephone network, and the radiating elements 12', respectively.
• circuitry e.g. transceiver circuitry included in a transmitter/receiver forming parts of a cellular base station in a mobile telephone network, and the radiating elements 12', respectively.
• a radiating patch 30' operating as the effective radiating element of the antenna assembly 1' .
• Fig. 6 shows another modified version of the second embodiment, where corresponding parts are provided with numerals having a ter notation ("') .
• the PCB 10"' is secured to the planar portion 21"' by means of screws 16" 'a extending through the bottom wall 20"' of the reflector housing, spacer elements 18"', the PCB 10"' and the central planar portion 21"' of the reflector.
• figs. 7-10 there are illustrated various forms of radiating elements on the front side of the PCB, inside the respective opening 22,22' or 22".
• fig. 7 there is a single slot 12' in the ground plane layer 11', fed by a lower feeding element 13' in the form of a microstrip line, as m the embodiment shown in fig. 4.
• fig. 8 there is shown a similar slot 12 ' a m a ground plane layer 11 'a, fed by a feeding element 13 'a for feeding two different patches 30' and 31' operating m two different frequency bands or m a single, relatively wide band.
• Fig. 9 illustrates a ground plane layer lib, m which there is formed a dipole arm 12b co-operating with a supplementary dipole arm of a feeding element 13b, so as to form a dipole- type radiating element 12b, 13b.
• a ground plane layer lie being cut out by etching into a spiral-like configuration 12c, which is connected (through the PCB) with a feeding element so as to form a radiating element .
• each radiating element is operable to transmit and/or receive RF signals.
• the antenna assembly can be used m combination with a transmitter and/or a receiver.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Computer Networks & Wireless Communication (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Aerials With Secondary Devices (AREA)
• Waveguide Aerials (AREA)

Priority Applications (2)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26663683

Family Applications (2)

Family Applications After (1)

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Cited By (10)

Families Citing this family (21)

Citations (4)

• 2000
  • 2000-10-27 AU AU14255/01A patent/AU1425501A/en not_active Abandoned
  • 2000-10-27 CN CN 00800741 patent/CN1336024A/zh active Pending
  • 2000-10-27 EP EP00976489A patent/EP1247311A1/en not_active Withdrawn
  • 2000-10-27 WO PCT/SE2000/002114 patent/WO2001041256A1/en not_active Application Discontinuation
  • 2000-11-30 AU AU19114/01A patent/AU1911401A/en not_active Abandoned
  • 2000-11-30 WO PCT/SE2000/002392 patent/WO2001041257A1/en active Application Filing

Patent Citations (4)

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