Dipole feed arrangement for corner reflector antenna

An antenna device, comprising a dielectric substrate board (10), dipole means (16) formed on the substrate board (10), and reflector member (48, 70, 72) having first and second reflective surfaces which are aparallel to each other define a first angle between each other. A positional relationship between the substrate board (10) and the reflector member (48, 70, 72) is such that the substrate board (10) and a vertex of the first angle (α) substantially lie in the same plane and the first and second reflective surfaces lie on opposite sides of the plane, a second angle defined between the substrate board (10) and the first reflective surface being different from zero each. In this way, an antenna device suitable for use in a broad variety of applications is provided which allows easy modification of its antenna characteristics by adjusting the angle between the reflective surfaces and/or the angular position of the reflector member (48, 70, 72) with respect to the substrate board (10).

The present invention relates to an antenna device, comprising a dielectric substrate board, dipole means formed on said substrate board, and reflector means having first and second reflective surfaces which are aparallel to each other and define a first angle between each other.

Such an antenna device is known e.g. from U.S. Pat. No. 5,708,446. The antenna device known from this document comprises a right-angle corner reflector having two orthogonal reflective plate members. A dielectric substrate board having a plurality of dipole elements printed thereon is arranged in parallel to and spaced from a first one of the reflective plate members. The substrate board is secured to the first reflective plate member via a spacer member of a low dielectric constant. The described antenna is not suited for broadband application and does not offer specific radiation patterns.

Another antenna device is known from JP 09-162637. The antenna device described in this document comprises a middle plate with radiation elements and a reflex angle corner reflector consisting of two reflecting planes extending in an angle from the middle plate comprising the radiation elements. However, the structure of the described antenna is quite complex since the reflex angle corner reflector consists of different separate elements, i.e. separate reflector planes so that the manufacturing costs are high. Further, the feeding network and the shape of the radiation element of the described antenna are not adapted for broadband applications.

The object of the present invention is therefore to provide an antenna device with a simple structure which can be manufactured in a simple and cost effective way. Further, the new antenna structure should be operable in a large variety of different applications and should be suited for broadband operation.

To achieve the above object, the present invention provides an antenna device, comprising:a dielectric substrate board,dipole means formed on said substrate board, andreflector means having first and second reflective surfaces which are aparallel to each other define a first angle between each other, and are formed on a single reflector member, whereby a positional relationship between said substrate board and said reflector means is such that said substrate board and a vertex of said first angle substantially lie in a same plane and said first and second reflective surfaces lie on opposite sides of said plane, a second angle defined between said substrate board and said first reflective surface and a third angle defined between said substrate board and said second reflective surface being different from zero each.

Particularly the construction of the reflector means with a first and a second reflective surfaces formed on a single reflector member enables a very simple structure of the new and inventive antenna device which can be manufactured at low cost. Particularly, the shape and the relationship of the first and the second reflective surfaces in respect to each other can be modified very easily by bending and/or curving the reflector means in an appropriate way in order to match the requirements for the specifically wanted application.

The antenna device according to the present invention thus offers a high degree of freedom in modifying the antenna characteristics and specifically the antenna pattern. A first possibility to modify the antenna characteristics is to adjust the angular relationship between the first and second reflective surfaces. It has been shown that by adjusting the first angle (which is the angle formed between the two reflective surfaces) the antenna pattern of the antenna device according to the present invention can be modified. A second possibility is to vary the angular position of the dielectric substrate board with respect to the first and second reflective surfaces. In this way, the ratio of the second angle (which is the angle formed between the first reflective surface and the substrate board) to the third angle (which is the angle formed between the second reflective surface and the substrate board) can be varied, independent of the first angle. It has been shown that this ratio has an impact on the antenna pattern, too. Depending on the particular application, a desired antenna pattern can thus be obtained by suitably adjusting at least one of the angular relationships between the first and second reflective surfaces (i.e. the first angle) and the angular position of the substrate board with respect to the first and second reflective surfaces (i.e. the ratio between the second and third angles). The present invention thus proposes an antenna structure which allows to build a low cost high gain antenna in the elevation plane and 180° degree (wide) pattern in the azimuth plane. The easy way of modifying the antenna characteristics enables the antenna device according to the present invention to be used in a broad variety of applications. Particularly, the antenna device according to the present invention is extremely broadband and offers around 40% of the bandwidth around the center frequency.

In the antenna device according to the present invention, the second and third angles may be equal to each other or different from each other. Preferably, they may range from 10 degrees to 170 degrees each. Depending on the desired application, the first and second reflective surfaces of the reflector means can either be plane surfaces or curved surfaces. Hereby, it may be advantageous if the reflector member is made from a plate member which is bent essentially into a V-shape having a fold line at said vertex of said first angle. Hereby, the vertex lies on the sharp edge of the V-shaped plate member. The reflective surfaces can hereby be plane or curved surfaces. Alternatively, the reflector means may be bent into a curved shape with no sharp edges, as e.g. a semi-elliptic or semi-circular shape. In this case, the vertex does not have to be a geometrically distinctive line but may be any appropriate line on the curvature.

In a further alternative, the reflector member may advantageously form a closed ring in its cross-section. Hereby, the closed ring may have a circular shape, an elliptic shape, a rectangular shape or the like. The reflector member forming the closed ring is particularly advantageous for applications in which an omni-directional radiation pattern in the azimuth angle and a high gain pattern in the elevation angle is required. This type of antenna is particularly suited for applications in multi-system base stations (e.g. GSM and UMTS systems may be covered by the same antenna), future software radio base stations, ultra wideband-systems access points and the like. This type of antenna is thus specifically advantageous for the application and use in different geographical areas without a need to specifically re-design the antenna structure for each application. Particularly the wideband or broadband operability of the proposed antenna structure covering 40 to 70% of the center frequency of operation is very advantageous.

Advantageously, the dipole means are arranged outside of the reflector means, whereby first dipole means are located outside a first vertex and second dipole means are located outside a second vertex. The inside is here the inner part of the closed ring of the reflector member, the outer side of which entirely reflects radiation from the dipole means in every direction. Hereby, the first and the second dipole means may be located outside a respective opposite side of the reflector means, whereby third and fourth dipole means are located outside the reflector means in a plane perpendicular to the plane of the first and the second dipole means. In other words, in a cross-sectional view of the proposed antenna, the four dipole means are located at 90° to each other around the closed ring of the reflector member. E.g., if the closed ring has a rectangular or quadratic shape, the dipole means can be located along each edge.

Further advantageously, the dipole means are arranged in a distance between 0.1 and 0.4 λ from the reflector means, λ being the wavelength of the center frequency of operation of the antenna device. It is particularly advantageous if the dipole means are arranged in a distance of 0.25λ from the reflector means.

When the reflector member is formed with a slot substantially at said vertex of said first angle, the substrate board may be inserted so as to extend therethrough. In this way, the reflector member can be easily secured to the substrate board. Advantageously, the width of said slot substantially corresponds to the thickness of said substrate board.

Metal strip means for supplying signals to and from said dipole means may be formed on said substrate board. It may happen that said metal strip means comprise at least one strip segment which crosses said reflector member. In order to avoid disturbation of the signals being transmitted over the strip segment by the reflector member, said slot of said reflector member advantageously has an enlarged slot portion where said strip segment crosses said reflector member. The enlarged slot portion preferably has a rounded contour.

The dipole means may comprise at least one dipole element having first and second dipole portions for radiating and receiving electromagnetic signals, said first dipole portion being formed on a first board face of said substrate board and said second dipole portion being formed on a second board face of said substrate board opposite to said first board face. The metal strip means may comprise at least one strip segment crossing said reflector member on each of said first and second board faces. Then, said slot of said reflector member advantageously has an enlarged slot portion in allocation to each strip segment.

Further advantageously, the reflector means is forming the support of said antenna device.

The present invention further provides a group of antenna devices of the kind described above, wherein each antenna device of said group differs from every other antenna device of said group in at least one of said first angle and the ratio of said second angle to said third angle. Alternatively, the group of antenna devices can comprise only identical antenna devices of the kind described above.

The antenna device illustrated inFIGS. 1 and 2comprises a dielectric substrate board10having a first (front) board face12and a second (back) board face14. An array of dipole elements16for radiating and receiving electromagnetic signals is formed on the substrate board10. Also, a feeding network18generally designated by18is formed on the substrate board10and serves for supplying signals to and from the dipole elements16. Each dipole element16has a first dipole portion20printed on the front board face12of the substrate board10and a second dipole portion22(illustrated in dashed lines inFIG. 1) printed on the back board face14of the substrate board10. The feeding network18is designed as a balanced microstrip feeding network which is formed of metal strip lines printed on the front and back board faces12,14of the substrate board10.

To explain the term balanced microstrip feeding network, reference is made toFIG. 8. Abalanced microstrip line24formed on the substrate board10is shown in cross section. The balanced microstrip line24comprises a first metal strip line26printed on the front board face12of the substrate board10and a second metal strip line28printed on the back board face14of the substrate board10. The metal strip lines26,28are arranged in parallel to each other and symmetrically with respect to a middle plane M of the substrate board10. Balanced microstrip feeding network means the the feeding network18is comprised of balanced microstrip lines like the balanced microstrip line24shown in FIG.8.

Specifically, the feeding network18is designed with a tree structure having a plurality of T junctions30serving for branching out the feeding network18to the dipole elements26. Each T junction30has a compensation gap32to compensate for the influence of the junction discontinuity. Furthermore, the feeding network18comprises tapered impedance transformers34serving for impedance matching. The T junctions30and the impedance transformers34have a balanced microstrip structure, too.

For more details on the feeding network18and its connection to the dipole elements16it is referred to U.S. Pat. No. 6,037,911 which is incorporated herein by reference. This document shows a similar tree-shaped feeding network designed with a balanced microstrip structure.

As illustrated inFIG. 2, a front-end device36can be mounted on the substrate board10. In order to integrate the antenna device with the front-end device36on the same substrate, a suitable transition from the balanced microstrip feeding network18to the transmission line technology of the front-end device36has to be provided on the substrate board10. InFIG. 1, a balun38provides for a transition from the feeding network18to an unbalanced microstrip structure which is assumed to be used in the front-end device36for signal transmission. In order to explain an unbalanced microstrip structure, reference is made to FIG.9. There, a metal strip line40is printed on one of the board faces of the substrate board10, here the front board face12. A metal backing42is printed on the other board face (here14) of the substrate board10. The backing42is much broader than the strip line40.

To provide for the transition between the unbalanced microstrip structure and the balanced microstrip structure, the balun38comprises a metal strip line44printed on one of the board faces of the substrate board10, here the front board face12, and an exponentially widening metal backing segment46(illustrated in dashed lines inFIG. 1) printed on the other board face (here14) of the substrate board10.

It is to be undestood that in case of a waveguide technology being used in the front-end device36, the balun38will be replaced by a suitable waveguide to balanced microstrip transition element. In case of a coplanar line technology or a coaxial line technology being used in the front-end device36, a coplanar to balanced microstrip or a coaxial to balanced microstrip transition element will be provided instead of the balun38.

A reflector member48made of metal or of a metallized plastics material is supported on the substrate board10. The reflector member48has two plane reflective surfaces50,52situated on opposite sides of the substrate board10with respect to the board's middle plane M. The reflective surfaces50,52are angled with respect to each other and with respect to the substrate board10and intersect at the level of the substrate board10. Their position with respect to the dipole elements16is such that a line of intersection54(cf.FIG. 1) of the reflective surfaces50,52is substantially parallel to the direction of a dipole axis56of each of the dipole elements16. As shown inFIG. 2, a first angle defined between the two reflective surfaces50,52is designated with α, a second angle defined between the reflective surface50and the substrate board10is designated with β and a third angle defined between the reflective surface52and the substrate board10is designated with γ. The angles α, β,γ are all different from zero. It can be clearly seen that the vertex of the first angle α substantially lies in the middle plane M of the substrate board10.

In the embodiment shown inFIGS. 1 and 2, the reflector member48is made in one piece from a single plate member by bending the plate member along the intersection line54into a V shape. Bending of the plate member is preferably carried out so as to result in a rather sharp fold edge, as shown inFIG. 1, although it is possible for the bending process to give a rounded fold region after bending. A corresponding embodiment with curved or rounded reflection means are shown inFIGS. 4,5and6explained further below. It is principally envisageable to arrange the V shaped reflector member48behind the substrate board10with respect to the main radiation direction of the dipole elements16, as indicated inFIG. 2by dashed lines58, and to secure the reflector member48to the substrate board by suitable fastening means. However, the distance from the dipole elements16to the reflective surfaces50,52would be relatively great in this case. It is advantageous to arrange the dipole means16, i.e. their longitudinal axis56as indicated inFIG. 1, in a distance between 0.1 and 0.4λ from the vertex, i.e. the fold line54in the example shown in FIG.1. λ is the wavelength of the center frequency of the operation of the antenna device. Particularly advantageously, the dipole means16are arranged in a distance of 0.25λ from the reflector means48. In order to enable the reflective surfaces50,52to be arranged more close to the dipole elements16, the reflector member48is formed with an elongated slot60extending along the intersection or fold line54, as can be seen in FIG.7. The slot60allows the reflector member48to be put over the substrate board10by inserting the latter into the slot60. The width of the slot60substantially corresponds to the thickness of the substrate board10. The slot60can be open at one end thereof toward the periphery of the reflector member48. Alternatively, it can be formed entirely within the periphery of the reflector member48, as is the case in the embodiment illustrated in FIG.7. Conveniently, the slot60is formed in the reflector member48before bending thereof, e.g. by punching.

As can be seen inFIG. 1, insertion of the substrate board10into the slot60makes several strip line segments62of the feeding network18on both board faces12,14of the substrate board10to cross the reflector member48. In order to avoid discontinuities in the balanced microstrip lines including these strip line segments62, the slot60is formed with a lokal slot enlargement64wherever one of the strip line segments62extends through the reflector member48(see FIGS.1and7). In this way, a “tunnel” is created for each strip line segment62. The slot enlargements64are preferably rounded, e.g. part-circular or part-elliptic. Their size and shape are designed so as eliminate any disturbances that might be imposed on the signals travelling along the strip line segments62by the material of the reflector member48.

An optional radom66may be provided to protect the antenna device. From a practical point of view, the radom diameter may be about 12 cm in case of a 2,4 GHz application and 1 cm or less in case of a 60 GHz application.

It has been shown that in the antenna device according to the present invention the antenna pattern and specifically the radiation angle in azimuth, i.e. in a plane parallel to the substrate board10, can be modified by changing the angles α, β, γ. Such modification can be easily performed by bending the reflector member48to a different angle α and/or arranging the substrate board10at a different angular position with respect to the reflector member48, thus changing the ratio of the second angle β to the third angle γ. In particular, in the antenna device according to the present invention, a wider radiation angle in azimuth can be obtained at a larger value of the angle α and a narrower radiation angle can be obtained at a smaller value of the angle α. Each of the angles β, γ preferably will be chosen within a range from 10° to 170°. In the embodiment ofFIGS. 1 and 2, the angles β, γ are substantially equal to each other and are approximately 125° each.FIG. 3shows a further embodiment in which each of the angles β, γ is smaller than 90° and is approximately 45°. The angles β, γ are not required to be equal; different values can be chosen for them. As an example, dashed lines68inFIG. 6illustrate a case in which the reflective surfaces of the reflector member are arranged asymmetrically with respect to the middle plane M of the substrate board10.

FIG. 4shows schematically a perspective view of a further embodiment of an antenna device according to the present invention. The embodiment shown inFIG. 4comprises a reflector member70having a circular shape in its cross section. In the respective view shown inFIG. 4, the reflector means70has a cylindrical shape. The reflector member70consists either of metal or metallised plastic. In the embodiment shown inFIG. 4, a dielectric substrate board10with a first board face12and a second board face14similar to the one shown inFIG. 1is provided. The structure of the feeding network18and the dipole element16of the embodiment shown inFIG. 4are essentially identical to the one shown inFIG. 1, so that all statements made above in relation to the embodiment ofFIG. 1also apply to the embodiment shown in FIG.4. The only difference is that the dielectric substrate board10extends along a symmetric middle plane of the cylindrical reflector member70so that dipole elements16are respectively located on opposite sides of the reflector member70in order to radiate and receive electromagnetic signals to and from, respectively, opposite directions. The dipole elements16on both sides of the reflective member70are connected to a common feeding network, i.e. balanced and tapered microstrip lines74leading to a common balun38forming the transition from the balanced middle strip line feeding network to an unbalanced feeding line consisting of the metal strip line44and the exponentially widening metal backing segment46printed on the other board phase of the substrate board10. The corresponding T-junction30combining the tapered microstrip lines74has a compensation gap76to compensate for the influence of the junction discontinuity. Similar as in the embodiment shown inFIG. 1, the substrate port10extends through slots60on opposite sides of the cylindrical reflector member70in the embodiment shown in FIG.4. The slots60of the reflector member70also have the shape shown in and explained in relation to FIG.7. The cylindrical reflector member70is made in one piece from a single plate member by bending the plate member into a cylindrical shape. In contrary to the embodiment shown inFIG. 1, the reflector member70does not have any sharp folding edge, but a continuous curvature. As can be seen inFIG. 5which also shows an embodiment of the antenna device with a cylindrical reflector member72, the vertex of the angle α can hereby be formed by any intersection of a tangential plane T of the cylindrical reflector member72and the middle plane M1of the substrate10. Since the shape of the reflector member70is cylindrical, its cross section is circular as can be seen in FIG.5and also in the similar embodiment shown inFIG. 6, whereby the angle α equals 180°, and the angles β and γ equal 90°, respectively.

FIG. 5shows another embodiment of an antenna device according to the present invention with a circular reflector element72similar to the embodiment shown in FIG.4. However, in the embodiment shown inFIG. 5additional substrate boards78and84are provided, which extend perpendicular to the substrate board10, so that a cross-like shape is achieved. Each dielectric substrate board78and84has a first board face and a second board face onto which dipole elements16for radiating and receiving electromagnetic signals are printed, identical to the dipole elements16of the substrate boards10. Further, both dielectric substrate boards78and84comprise a feeding network18as shown and explained in relation toFIGS. 1 and 4. In the embodiment shown inFIG. 5, the antenna device thus has four sets of dipole elements16arranged in angles of 90° in respect to each other, whereby the feeding network18of the dielectric substrate board84is connected to the corresponding part of the feeding network18of the dielectric substrate board10by means of a cable or band connection96, whereas the feeding network18of the dielectric substrate board78is connected to the corresponding part of the feeding network18of the substrate board10by means of a functional block94which provides a power splitting.

Optionally, support means92and90can be provided in order to provide mechanical support for the antenna device. The support members90,92preferably consist of non-conductive materials, like plastic. Alternatively, however, the reflector member70ofFIG. 4or72ofFIGS. 5 and 6is adapted and shaped to form mechanical support for the antenna device, so that no further support elements are necessary.

The embodiment shown inFIG. 6is very similar to the one shown inFIG. 5, except that four substrate boards98are provided, in contrary to the embodiment shown inFIG. 5, in which only three substrate boards are used. In the embodiment shown inFIG. 6, each dielectric substrate board98extends in an angle of 90° in respect to its adjacent substrate boards98. Each substrate board98has a first board face100and a second board face102and comprised dipole elements16and a feeding network18as shown in and explained in relation to FIG.1. The connection between the four substrate boards98is achieved with a small connecting structure106for providing power splitting e.g. by using a chip based broad band power splitter as alternative to a reactive broad band tapered power splittered printed on the main substrate10as in the embodiment of FIG.5. The embodiment shown inFIG. 6further comprises support elements104between the respective substrate boards98, advantageously consisting of non-conductive material, like plastic.

It is to be understood that the cylindrical shape of the reflector member70or72of the embodiments shown inFIGS. 4,5and6is only an example and that other shapes may be used. E.g., the cross section of the ring shaped reflector member70may be elliptical, rectangular, hyperbolic, polynomial or the like. In case of a reflector member with a rectangular cross section, the set of dipoles can either be arranged along each corner of the reflector member, or e.g. in the middle of each of the four planes. It should be noted that the reflector member70,72may have in general a closed surface, having the same cross-section along its height. Alternatively, the cross-section may vary along the height.

It is further to be noted that all elements shown inFIG. 4having the same reference numerals as the corresponding elements in the embodiment ofFIG. 1have the same function and that all explanations in relation toFIG. 1also apply to the embodiment of FIG.4. The arrangement of the dipoles16and the feeding network18is further identically and correspondingly applied in the embodiments ofFIGS. 5 and 6. The same is true for the arrangement and the shape of the slot60, through which the substrate boards10,78,84and98extend. All explanations made in relation to the embodiment ofFIG. 1in this respect also apply to the embodiments shown inFIGS. 4,5and6.

FIGS. 10 through 14show a series of alternative embodiments of a dipole portion20or22for use in the dipole elements16. A feeding point of the dipole portion20,22where it is attached to the feeding network18is designated by70inFIGS. 10 through 14. The dipole portion20,22has at least three corners, and its feeding point70is situated at one of the corners (as shown inFIGS. 12to14) or at a short edge between two closely adjacent corners (as shown in FIGS.10and11). InFIG. 10, the dipole portion20,22has six corners, inFIG. 11eight corners, inFIG. 129three corners, inFIG. 13four corners, and inFIG. 14five corners. Further details on the dipole portion20,22can be taken from U.S. Pat. No. 6,037,911, again.

InFIGS. 15 and 16, exemplary antenna diagrams obtained by simulation are shown. The antenna diagram ofFIG. 15was obtained in a horizontal plane (azimuth), and the antenna diagram ofFIG. 16was obtained in a vertical plane (elevation). It has been shown that the antenna device according to the present invention can exhibit antenna patterns in azimuth and elevation which are approximately stable over the whole frequency range of interest.

The measured SWR diagram ofFIG. 17shows that the antenna device acording to the present invention can have an operation bandwidth (reflexion factor S11<2) better than 37% which can be further extended.

FIG. 18shows a 3D simulation of an antenna device according to the present invention used for a simulation, the results of which are shown inFIGS. 19to24. The simulated antenna device shown inFIG. 18is similar to the embodiment shown inFIGS. 5 and 6and comprises a cylindrical reflector104and four sets of respectively four dipole elements106, each set of dipole elements106being arranged in an angle of 90° to its adjacent sets of dipole elements. For faster calculation and simpler modeling reasons the substrate thickness of the simulated antenna device was considered to be zero, which should not significantly influence the performance, but should lead to an increase of the loss.

As becomes clear from the simulation results ofFIGS. 19to24, the gain is approximately stable in the entire frequency range of interest.FIGS. 19 and 20show simulation results for the antenna device shown inFIG. 18at a center frequency of operation of 3.4 GHz,FIGS. 21 and 22show simulation results for the antenna device shown inFIG. 18at a center frequency of 1.5 GHz andFIGS. 23 and 24show simulation results for the antenna device shown inFIG. 18at a center frequency of 3.4 GHz. Hereby,FIGS. 19,21and23respectively show diagrams of the gain obtained in a horizontal plane (azimuth) andFIGS. 20,22and24show diagrams of the gain obtained in a vertical plane (elevation). As can be seen, the antenna device according to the present invention can exhibit antenna patterns in the azimuth and elevation which are approximately stable over the whole frequency range of interest which leads to an operation bandwidth of around 80% of the center frequency of operation.

In the application scenario illustrated inFIGS. 25 and 26, the antenna device according to the present invention is integrated into a public outdoor wireless access point (POWAP)110mounted on a wall108. An expected radiation pattern for the POWAP110in microwave and mm-wave range is indicated by112. A similar radiation pattern would be expected in case of an RF based door opener.

FIG. 27shows a monitoring system for monitoring a sports field116. The monitoring system comprises a plurality of wireless cameras disposed around the sports field116; for example, the cameras comprise several stationary cameras118and a moving camera120. The video signals transmitted from the cameras118,120are received by a receiving station122situated midway a long side of the sports field116. The operation field of the receiving station122has to cover all of the cameras118,120as indicated by a dashed arrow124. This can be performed by using in the receiving station122an antenna device according to the present invention having a180degrees radiation pattern.

FIGS. 28 and 29illustrate use of the antenna device according to the present invention in an anticollision and guidance radar system for a vehicle126. In such a radar system, it is desired to completely observe the environment to the front and the sides of the car. To this purpose, car sensors each equipped with an antenna device according to the present invention can be mounted on the car at the sides and the front thereof. Dashed lines128,130,132show expected coverage areas for the car sensors in mm-wave range.

The antenna device according to the present invention has a high gain and a very large bandwidth and allows applications in communication systems working in the microwave or millimeter wave frequency range. A big advantage of the antenna device according to the present invention is the possibility to use the same antenna for different kinds of communication systems even at different frequency bands of interest. Possible identified mass market applications are e.g. broadband home networks, wireless LANs, private short radio links, automotive millimeter wave radars, microwave radio and TV distribution systems (transmitters and ultra low cost receivers). Some of the identified frequency bands of interest are: 2,4-2,7 GHz, 5-6 GHz, 10,5 GHz, 17-19 GHz, 24 GHz, 28 GHz, 40-42 GHz, 59-64 GHz, 76 GHz and 94 GHz. At the same time, the antenna device according to the present invention can satisfy the following general requirements made on mass market antennas: very low production costs, e.g. due to utilization of a simple planar technology, utilization of a printed technology and/or simple and cheap photolithographic processing of the prints; high reproducibility due to a low tolerance sensitivity; and simple integration with planar RF-assemblies. Furthermore, the antenna device according to the present invention features a specified radiation pattern, good matching in the frequency band of interest and a good efficiency in the frequency band of interest.