FR2533764A1 - - Google Patents

Abstract

THE INVENTION CONCERNS A MICROBAND ANTENNA AND ITS MANUFACTURING PROCESS. THIS MICROBAND ANTENNA 10 INCLUDES THE STRUCTURE OF A PRINTED CIRCUIT 20 SHAPED ON A POLYMERIC FILM 18, A FOAM OR A HONEYCOMB MATERIAL 16 SERVING BOTH AS A DIELECTRIC AND A SUPPORT FOR THE PRINTED CIRCUIT, AS WELL AS A SUPPORT OR RECEPTACLE 12 ACTING BOTH OFFICE OF GEOMETRICAL PLAN 14 AND SUPPORT OR RECEPTACLE FOR HOUSING DIELECTRIC 16 AND PRINTED CIRCUIT 20, THE ELEMENTS OF THE ASSEMBLY BEING ALL BOUND TOGETHER TO FORM A RIGID STRUCTURE. THE INVENTION IS USED TO PROTECT EXTERNAL ANTENNAS AGAINST WEATHER.

Description

1 P-DSF-22 / EN

  The present invention relates to the field of microstrip antennas or strip lines. More particularly, the present invention relates to a planar microstrip antenna intended to be used mainly as an antenna for receiving microwave broadcasting signals. Although the present invention may have general utility in the transmission or reception of microwave frequencies, it will be described in the context of using this

  what is called a television antenna to receive

  only in a direct transmission system.

  However, it is understood that the

  vention may have general utility either as

  receiving antenna, either as transmitting antenna in

  microwave communication systems.

  Because of the growth potential of

  transmission of signals from

  microwaves for transmission and retrieval systems

  television, it is becoming increasingly necessary to

  to develop a reliable, durable and

  reasonable cost for domestic use and other

  industrial applications for the reception of

  microwave signals transmitted by satellite

  traditionally reads satellite dishes in

  transmission systems of this type, but these

  Many problems arise for a system for receiving microwave television signals.

  effective and commercially viable Among other

  parabolic antennas are relatively expensive and they are not sufficiently stable, even in light winds, to guarantee a reception of

  uniform signals and hence the quality of the image.

  As a result, they are not particularly

  Suitable for daily use in home television reception systems

  or for other industrial applications.

  Antennas with microbands or lines

  tapes for transmitting or receiving hyper-

  S frequencies are known in the art.

  Examples of this type are illustrated, for example, in GB-PS 1,529,361, US-PS 3,995,277, US-PS 3,987,455 and US-PS 3,803,623. In all these prior patents, the antenna structure is consisting of a laminate of a dielectric material with an electrically conductive geometric plane on a surface of the dielectric and a

  drawing of microstrips or strip lines, on the

  surface of the dielectric It is well known that

  the properties of the dielectric material are important

  for the antenna performance, in particular the properties relating to the dielectric constant

  and the dissipation factor These considerations

  these conventional microstrip antennas

  inappropriate as television antennas for reception only, since they limit

  strictly the choice of the appropriate dielectric materials

  for very expensive materials, in particular when considering that a television antenna for reception only should be relatively large, for example, a square structure of the order of 76 cm to 102 cm side or a circular structure having a diameter of 76 cm to 102 cm Similarly, since reception-only television antennas will be used outside, they must be returned

  weather resistant to protect them against

  This effect is especially true with conventional microstrip or strip-line antennas of the prior art in which the printed circuit and the genomic Wlan are saturated with the outside of the dielectric surfaces. This requirement for weather resistance further accentuates the

  economic and practical problems posed by the use

  microband antennas of the prior art technique.

  in television systems to receive

only.

  The combined requirements concerning

  electrical properties and resistance to

  peries limit the choice of dielectric materials

  which can be used effectively in one year.

  convenient for reception only if the latter was carried out in accordance

  usual technical backgrounds Ceramic

  low loss could provide a good

  of the dielectric material, but the cost and the limited dimensions of the ceramic substrates could put the use of these

  substrates substrates based on polytetrafluoroethylene

  lene or other fluorinated polymers could also

  are acceptable choices from the point of view of dielectric properties, but the cost of these substrates could make them unsuitable for

  domestic use and industrial applications

  In general, therefore, for economic reasons,

  In practice, and other practical drawbacks, the technology has not developed a flat television antenna for reception only which is acceptable and

  practical from the industrial point of view.

  The problems of the prior art

  mentioned above, as well as others are

  read or attenuated by the antenna of the present invention.

  According to the present invention, there is provided a microstrip antenna comprising a polymeric film on one surface of which is realized a printed circuit, a

  layer of a dielectric material supporting film

  4- cule polymer, the printed circuit being realized on

  the surface of the latter which is turned towards this

  layer, as well as a support element comiiprenant ui plan

  geometrically designed to support the layer of dielectric material

  The components can be assembled and linked

  together to form a rigid assembly that constitutes

  kills a flat television antenna for uni-

  cally. Viewed in another aspect, the invention provides a method of manufacturing a microstrip antenna,

  this method comprising the steps of forming

  sea a laminated film of a sheet of polymeric material and a microwave printed circuit,

  to form a support element having a metal surface

  1 Suitable for use as a geometric plane, locating a dielectric material on the metal surface of the support member, locating the sheet of polymeric material on the dielectric material such that the printed circuit is facing the latter,

  then tie the dielectric material to the foil

  film polymer and the support element.

  Therefore, a geometric plane can be defined by the base surface of a bowl or other support

  which is either of metal or of a resinous material

  forced metal coating The printed circuit board

  may consist of a pattern of conductors

  formed on a surface of a polymeric film

  according to any usual technique-

  adopted in the production of printed circuits.

  The dielectric can be arranged geometrically to which

  it can be bonded. This dielectric can be a

  rigid foam, melted powder, honeycomb material or any other material

  self-supporting dielectric The micro-printed circuit board

  strips can be bonded to the dielectric, so that it is turned to the geometric plane, the polymer film

  used as a protective covering to seal the

  seems and provide protection against the weather.

  In a preferred embodiment, the microstrip antenna is therefore constituted by the geometrical plane which forms part of the support bowl, the dielectric bound

  the support, as well as the printed circuit linked to

  The protective covering formed by the sheet

  the polymer of the printed circuit substantially extends

  the expected life of this television antenna

for reception only.

  In order to allow an easy understanding of the present invention, certain embodiments will now be described by way of example with reference to the accompanying drawings, in which: FIG. 1 is a block diagram of the method of the present invention; FIG. 2 is an elevational view and

  partial section of a plane microwave antenna

  these according to the present invention; and FIG. 3 is a view similar to FIG. 2, but illustrating a second embodiment of a flat television antenna for reception only

of the present invention.

  Reference is first made to Figure 2 which

  illustrates an embodiment of a television antenna

  flat view for reception only according to the pre-

  This flat antenna 10 has a lower bowl 12 with a base surface 14.

  surfacel 4 is the geometric plane of an antenna for hyper-

  The bowl 12 may be either a bowl of a metal such as aluminum, or a molded unit, for example, of a fiberglass-reinforced resin,

  the surface 14 being metallized This bowl 13 con-

  holds a dielectric material 16 which, in the embodiment of Figure 2, is a foam material (self-supporting or two-part) converted into foam

  in situ and adhering to the inner surfaces of the cu-

  The foam 16 defines the dielectric medium for the microwave antenna. Foam 16 will typically have a dielectric constant of about 1 to about 4 and a loss tangent in the range of about 0.001 to 0.01. foam can

  also be formed in a separate operation, tail-

  dimensioned, then glued to the bowl.

  dielectric re can also be a melted powder

  or an equivalent material Alternatively, the dielectrics

  that can be a mixture of synthetic resin / glass,

  containing microbubbles of glass.

  The dielectric material 16 is covered with a sheet of polymer film on which is defined a microwave circuit board. The polymer film 18 and the printed circuit board 20 may be formed using any conventional circuit manufacturing technique. printed matter, and they are related to the dielectric material 16 to form a

  rigid assembly As can be seen in

  2, the bowl 12 forms a housing which contains the other components (i.e. the dielectric material and the printed circuit of the antenna).

  a completely integral rigid rigid structure.

  In addition, the polymer film 18 constitutes a layer

  protection against the elements for the di-

electrical 20.

  Appropriate electrical connections (not shown

  shall be connected to the geometrical plane and to the printed circuit for the purpose of putting the

  television for reception only.

  For the application of the television antenna

  for reception only that is considered main-

7 2533764

  according to the present invention, the structure will be relatively large, in this case a square or rectangle of the order of 76 cm to 102 cm side or a circle with a diameter of 76 cm to 102 cm for a reception correct signals and maintaining a

  uniform picture quality in the TV receiver.

  to which the antenna is connected, it is important that the spatial relationship between the electronic components remains constant -As a result, the rigid and

  dimensionally stable structure of the pre-

  This invention is particularly important for the realization of this purpose. The bowl 12 is made of either a metal or a rigid polymeric material, preferably a fiber-reinforced material, with a metallized inner surface. When properly cured, the foam 16 is rigid and dimensionally stable Although they are flexible when not supported, the

  printed circuit 20 and the polymer sheet 18 are

  rigidly supported on the upper surface

  In this way, all the assembly

  becomes rigid and dimensionally stable.

  The microstrip printed circuit 20 is designed and selected so that it could generate

  a plane wave if it was a microwave transmitter.

  Since the receivers and transmitters with

  frequencies are reciprocal, the printed circuit 20 receives

  a plane wave coming from a specific direction,

  for example, an equatorial or geostationary satellite

  The polymer sheet 18 should ideally have a

  thickness of about 1/2 wavelength of the signal

  to be captured (12-14 GHz for the stationary satellite).

  re OTS currently in service); however, this confi-

  ideal guration may not be practical As a result,

  the thickness of the sheet 18 may be in a range of

8 2533764

  on the order of 0.0025 cm to 0.25 cm, which will give rise to certain losses by reflection, but will allow

  always to get an acceptable unit antenna.

  The dielectric constant of the foam 16 should be kept within acceptable limits of between about 1 and 4 and this foam should be

  have a low loss factor of a tangent of

  0.01 or less to be acceptable for

  use in the television antenna to receive

  only in accordance with the present invention.

  Referring now to FIG.

  is a block diagram illustrating the training process

  An antenna of Figure 1 A laminate of a sheet of polymeric material and a metal coating

  is formed in Step A, then subjected to a

  during step B in order to realize the cir-

  printed microwave or radiation 18.

  Separately and simultaneously or at a selected time interval, the cuvette 12 is formed in step C. The cuvette 12 is then filled with a suitable dielectric material, for example under

  foam material or hardened powder

  sand The bowl can be filled with a dielectric material at a level slightly above its top The laminated polymeric film on which

  is formed the circuit board, is then placed

  above the dielectric, so that the printed circuit 20 is directed downwards, that is to say toward the base of the bowl 12, which constitutes the geometric plane This operation is performed during step E during step F, the assembly is subjected to a slight pressure, so that the film 18 is kept parallel to the base of

  While under pressure, the assembly

  composite is then heated to harden and

9 2533764

  the dielectric, which then adheres to both the inner surfaces of the cuvette and the polymer film to seal the entire assembly. Reference is now made to Figure 3 which

  illustrates a modified embodiment of a

  tenne television for reception only in the-

  a honeycomb material 22 is housed inside a bowl 12 and acts as a support

  for the microwave circuit consisting of

  The honeycomb material has walls 24 which define

  cells or air spaces 26 In the configuration

  FIG. 3, the air contained in the cells

  26 forms the main dielectric material for the year

  unitary microwave frequency. Obviously, the

  of which the honeycomb structure consists of

  the, is also part of the dielectric system, so that the honeycomb material must have

  loss characteristics and a dielectric constant

appropriate cue.

  As can be seen from both

  Figures 2 and 3, the dielectric material

  16 and the honeycomb structure 22 serve as a support for the microwave circuit structure consisting of the film 18 and the conductors 20, as well as the transmission medium for the microstrip antenna. film 18 is not in itself a component of the microwave circuit system, but rather provides environmental protection for the assembly, while providing a convenient means for defining the circuit

microwave.

  From the description above, it is understood

  that the present invention provides a television antenna p) Ilne for receipt iiniquelument which is

  particularly effective, practical and economical.

  This antenna has stable dimensions and, consequently,

  it can be mounted on the outside of buildings

  mounts (especially on attics or other structures

  similar) and it can be installed in a

  rotating head for directional alignment without

  affect the reception of the transmitted signal and, by

  the uniform quality of the image appearing

  on the screen of the television set to which the

  tenne is connected A special feature

  important and useful for outdoor antennas.

  res resides in the fact that the antenna is protected from the weather by its entire structure

  unitary and waterproof, while the superior film

  re 18 protects both the printed circuit and the diode

  This means that this antenna can be used outdoors during

many years.

  Although we have illustrated and described

  my favorite realization, various modifications

  and substitutions can be envisaged without

  the spirit and scope of the invention.

  quence, it is understood that the present invention has been

  described by way of illustration and not in a

mitatif. 1 2533764

Claims (14)

  Antenna with microstrips comprising a pel-   polymer on one surface of which is realized   a printed circuit board, a layer of a material   electrical device supporting the polymer film, the printed circuit being formed on the surface thereof which is turned towards this layer, and a support element comprising a geometric plane and intended to   support the layer of dielectric material.   2 microstrip antenna according to the   cation 1, characterized in that the polymer film is bonded to the dielectric material, which is bonded to the support element.   3 microstrip antenna according to claim   cation 1 or 2, characterized in that the support element   is a bowl that contains the dielectric material.   4 microstrip antenna according to claim   cation 4, characterized in that the bowl has a base and sides, the geometric plane being located in the base.   Antenna microstrip according to the claim   cation 3 or 4, characterized in that the bowl is metallic.   6 microstrip antenna according to claim   cation 3 or 4, characterized in that the bowl is   consisting of a rigid polymeric material with a metallized face.   7 Microband antenna according to any one   shell of claims 1 to 6, characterized in that   that the dielectric material has a dielectric constant   that is between about 1 and 4.   8 Microband Antenna according to any one   one of claims 1 to 7, characterized in that   that the dielectric material has a tangent of loss 0.01 or less.   9 Microband antenna according to any one 1 _   one of claims 1 to 8, characterized in that   that the dielectric material consists of a   honeycomb and the air contained in the cells of the honeycomb.   10 Microband Antenna according to any one   one of claims 1 to 9, characterized in that   that the polymeric film is a sheet of material having a thickness of about 1/2 wavelength   microwave signal to be picked up by the tenne.   11 Microband antenna according to any one   shell of claims 1 to 10, characterized in that   that the polymeric film is a sheet of material having a thickness of between about 0.0025 cm and 0.25 cm.   A method of manufacturing a microstrip antenna, comprising the steps of   to form a laminated film of a sheet of   re polymer and microwave circuit board,   to form a support element having a metal surface   suitable for use as a geometric   a dielectric material on the metal surface   the support element, locate the sheet of paper   polymeric material on the dielectric material so that the printed circuit is turned towards this   last, then bind the dielectric material to the sheet.   the film polymer material and the support member.   The method of claim 12, wherein   characterized in that the dielectric material is under   form of a curable foam or powder when   that it is on the support element, the step of   connection of the dielectric material to the sheet of   polymer and the support element consisting of   powder or foam to form a thin layer 13 2533764 gide of dielectric material.   The process of claim 13, wherein   characterized in that the support member is a bowl   with a base and sides, the locating step   S tion of the dielectric material on the support element of filling the bowl with a foam or a curable powder.   Process according to Claim 12 or 13,   characterized in that the laminated film is   held parallel to the support element during the   hardening of the dielectric material.