EP0927437B1 - Mobile radiotelephony planar antenna - Google Patents

Abstract

The invention relates to a planar antenna (1), in particular for mobile radio, the planar antenna (1) having two conductive layers arranged at a predefined distance from one another, the conductive layers being plates (2, 12, 20, 20'; 3, 13, 30, 30') or sheets which are plane-parallel with one another, the first layer (2, 12, 20, 20') having a surface that is symmetrical with respect to a symmetry axis (15) and the second layer (3, 13, 30, 30') being a subregion of the surface of the first layer, the second layer being formed by reducing, or respectively cutting off or leaving out a part of the first area along a straight line or chord (4, 14, 40, 40') extending at right angles to the symmetry axis (15), and the chord of the second layer forming a rectilinear edge, and the two layers being conductively connected to one another, the conductive connection being made by pointwise-arranged or strip-like connection elements (15, 19) on the border (8, 18) of the layers which is remote from the chord (4, 14, 40, 40').

Description

The invention relates to a planar antenna, in particular for Mobile radio, the planar antenna being two in one predefined Has spaced conductive layers.

The field of application of the invention relates primarily on the mobile radio area and here in particular on the E and D networks.

Known antenna solutions for the area of Mobile radio applications are based on linear antenna designs in Form of monopoly orders in shortened or unabridged Execution. These linear antennas are both external mountable on-board antennas as well as directly with the Terminal-coupled components known and with different directional factor and efficiency, where these components in the azimuth plane only are omnidirectional. Known flat antenna solutions are based on areal, dipole-like configurations, their Directional diagram irregular and in connection with the respective Underlying the characteristics of a significant Have radiation field deformation. The on the Radiation properties related to application are those inferior to the classic linear antennas. Likewise are targeted blanking properties of the Radiation diagram undetectable. In addition, there are none Known solutions whose electromagnetic or Radiation properties based on asymmetrical and open waveguide techniques, especially the Microstrip technology, using self-supporting conductive Foil conductors or foil-like guide surfaces can be achieved.

A planar antenna is known from EP 0 176 311 A2, which has a ground plane that is medium to a dielectric The substrate layer is kept at a distance from the radiator element is. The radiator element is made by means of a coaxial Waveguide fed and is by means of short-circuit connections electrically conductive on one side with the ground plane connected. The radiator element is a geometrical partial surface the ground plane. One is also known from EP 0 176 311 areal short circuit connection between ground level and Radiator element known.

DE 195 04 577 A1 describes a mobile radio antenna for Motor vehicles known that also have a radiation element has that with the inner conductor of a coaxial Vellenleitun is connected. One side of the radiator element is over a short circuit connection with a ground plane in Connection. From this publication is a planar antenna for the Mobile radio according to the preamble of claim 1 or claim 3 known. The object of the present invention is an areal Radiator component with the property of the producibility of a linearly polarized and spatially broad sector radiation as well in the azimuthal as well as in the elevation plane as well as one pronounced attenuation and thus one Useful radiation only within a spatial hemisphere preferably in the spectral ranges between 890 MHz and 960 MHz or 1710 MHz and 1890 MHz.

This task is performed according to the characteristic part of the Claim 1 solved inventive. Through the conductive Connections of the two layers will reduce the Size achieved by approximately a factor of 2, since λ / 2 is advantageous Waves can be received. Because the distance between the straight edge and the shorted Border changes, it is possible in a relatively wide Receive and transmit spectral range. Here it is advantageous if the first layer is circular and the second layer opposite the first around a tendon section is reduced, the tendon section being the straight edge forms. Here, the conductive connections on the edge side facing away from the straight edge either by means of punctiform or strip-shaped connecting elements be realized. However, it is also advantageously possible Base area of the first layer elliptical, triangular, to be square or hexagonal.

The vibration conditions of the planar emitter can be advantageous using a simulation software for examination perform field problems of high frequency radiation. It should be noted that one for each spectral range Abundance of different vibration conditions depending on Emitter characteristics must be taken into account. There one full calculation taking this into account Boundary conditions is not possible is the specialist inevitably relies on simulation attempts, provided that he Planar emitter according to the invention for its conditions want to shape.

The vibration conditions of the planar radiator can also advantageously be influenced with diaphragms produced in the second layer by cutouts in the conductive layer. In this context, the diaphragms form implemented capacities with distributed parameters, which in this form electrically extend the waveguide geometry or offer the possibility of geometric miniaturization. The arrangement of the diaphragms is chosen symmetrically, since the condition of symmetry is the prerequisite for maintaining the preferred polarization of the electric field vector. Here, by means of the diaphragm position, there is the possibility of changing the direction of vibration of the field vectors primarily influenced by the diaphragms and thus of the resulting field profiles resulting from superposition. The location of the aperture insertion and, depending on the aperture contour, determine the degree of influence on the line currents and the associated electrical or magnetic field components. In this respect, the aperture position and contour primarily determine the increase or decrease of the capacitive or inductive components within the blind component balance. Since the apertures introduced fundamentally influence the complex waveguide properties, in addition to changing the spectral oscillation condition, this also gives the possibility of influencing the spectral bandwidth of the excited oscillation type. The area of each aperture can be either circular, elliptical, rectangular, square, triangular, hexagonal or irregular. The optimal shape of the diaphragms and their arrangement can usually only be determined empirically by simulation attempts.
The electromagnetic resonance-vibrating arrangement is excited or fed by means of a coaxial waveguide, the inner conductor of the waveguide being conductively connected to the second layer and the outer conductor of the waveguide being conductively connected to the first layer, and the inner conductor being axially symmetrical to the aperture boundary through a diaphragm within the first layer and is arranged without a galvanic connection to it.

The way the two layers along the the straight edge facing away from each other in Connection is freely selectable. So it is possible by means of conductive pins the two layers together connect. This is particularly advantageous if none Dielectric is arranged between the two layers and the two layers by e.g. Copper plates are formed. The conductive connecting pins then serve as if Spacers.

Unless there is a dielectric between the two layers is arranged, this can be used as a carrier for the two serve conductive layers, in which case the Conductive connection outside of the dielectric takes place for what the dielectric on its outer edge linear or surface can be coated.

The shape of the border on which the two layers are conductive are in principle freely selectable, however, compliance with the vibration conditions is required respect, think highly of. If the opposite of the straight edge or tendon Edges running parallel to the tendon can only be a monochromatic frequency response can be achieved. Therefore, it is necessary, this edge not parallel to to form a straight edge or chord of the second layer, if a frequency spectrum or band is desired.

The planar emitter according to the invention forms an optimal one Antenna component or replacement component of the Vehicle external antenna with the possibility of mounting within the Passenger compartment. The area of application relates further to general indoor applications by the Emitter component a spatially separated component of forms the respective end device and on the relevant room glazing is mounted inside and flat. It is too possible that the room glazing itself as dielectric Carrier of the conductive two layers is used.

The inventive radiator component or planar antenna is advantageously applicable in cases where the rear space located to the antenna aperture radiation-free or kept low in radiation and thus the electromagnetic Radiation exposure of the user should be minimized.

In addition, the invention forms Radiator component a basic module for short or Medium-range transmission systems for communication, sensor or safety-related applications.

Below we the planar antenna according to the invention using Figures explained in more detail.

Figur 1:

Eine Draufsicht auf eine erste Schicht;

Figur 2:

Eine Draufsicht auf die zweite Schicht des Planarstrahlers mit darunterliegender erster Schicht (Fig.1), wobei die erste und zweite Schicht auf einer Länge von L1 miteinander leitfähig verbunden sind;

Figur 3:

Draufsicht auf eine weitere Ausführungsform einer erfindungsgemäßen Planarantenne mit punktuellen leitenden Verbindungen;

Figur 4:

Draufsicht auf die zur ersten Schicht gemäß der Figur 3 gehörenden zweiten Schicht;

Figur 5,6:

Ein weiteres Ausführungsbeispiel einer erfindungsgemäßen Planarantenne mit kreisförmigen Blenden in der zweiten Schicht;

Figuren 7 - 9:

Einen Planarstrahler mit kreisförmigem Dielektrikum und auf diesen aufgetragenen leitfähigen Beschichtungen;

Figur 10:

Abstandshalter bzw. Stützzylinder;

Figur 11:

Punktförmiges Verbindungselement;

Figuren 12 - 15:

Draufsichten auf verschiedene Ausführungsformen von Planarstrahlern;

Figur 16, Figur 17:

Seitenansichten von Planarstrahlern mit an der Außenkante des Dielektrikums aufgetragenen elektrisch leitenden Verbindungselementen.

Show it:

Figure 1:

A top view of a first layer;

Figure 2:

A plan view of the second layer of the planar emitter with the first layer underneath (FIG. 1), the first and second layers being conductively connected to one another over a length of L1;

Figure 3:

Top view of a further embodiment of a planar antenna according to the invention with selective conductive connections;

Figure 4:

Top view of the second layer belonging to the first layer according to FIG. 3;

Figure 5.6:

Another embodiment of a planar antenna according to the invention with circular apertures in the second layer;

Figures 7-9:

A planar emitter with a circular dielectric and conductive coatings applied to it;

Figure 10:

Spacers or support cylinders;

Figure 11:

Point connector;

Figures 12 - 15:

Top views of different embodiments of planar emitters;

Figure 16, Figure 17:

Side views of planar emitters with electrically conductive connecting elements applied to the outer edge of the dielectric.

Figure 1 shows a low loss low dielectric Structural support 1 preferably made of Polypenco Q 200.5, polycarbonate or polystyrene, with a diameter of 93 mm and one Base height of 5 mm, which is closed on one side conductive layer 2, preferably consisting of copper or Aluminum with a layer thickness between 5 µm and 800 µm. The Conductive layer is preferably by means of additive or subtractive techniques.

On the side of the structural carrier 1 facing away from the closed conductive layer 2 there is a second conductive layer 3. This layer 2 is a segment of a circle which is reduced by a chord section compared to the first layer 2, the chord 4 being perpendicular to the axis of symmetry 15 of the layers 2, 3 is arranged. On the outer edge or boundary edge 8 lying opposite the rectilinear boundary edge or chord 4 of the conductive layer 3, the two conductive layers 2 and 3 are conductively connected to one another over the length L1, the counting of the halved length L _{1/2 in} each case being perpendicular to the rectilinear boundary edge 4 or the axis of symmetry 15 begins. The planar emitter is fed by means of a coaxial waveguide, the outer conductor of the waveguide, not shown, being connected to the conductive layer 2 in the area of the aperture 7 and the inner conductor of the waveguide, not shown, being led through the aperture 7 to the connection point 6 of the second layer 3 . The wave impedance of the waveguide is preferably 50 ohms. The electromagnetic diaphragm 7 is formed by a circular opening within the conductive layer 2 with the diameter of 3.2 times the inner conductor diameter of the coaxial waveguide. The length of the solder 80 changes continuously in the range L1, as a result of which a defined spectral range can be received or transmitted.

Figures 3 and 4 show an embodiment of a Planar antenna for the frequency range between 1710 MHz and 1890 MHz. According to Figure 3, a conductive metallic Plate 20 with a circular border and the diameter of 90 mm over a distance of 4.8 mm with a second conductive metallic plate 30, which as a circular section is executed, coupled in parallel, the Centers of both the full circle area and the Circular section surface on an identical axis of symmetry 15 be arranged and according to Figure 4, the conductive plate 30 at five points 50, one of the five points 50 of the in the plane of the circular section surface symmetry line 15 of the assembly is positioned with the conductive plate 20 is coupled by conductive Connecting elements 5 according to FIG. 11 to those in FIG. 3 marked position between the conductive plate 20 and the conductive plate 30 are introduced. The galvanic coupling of the inner conductor of the coupling coaxial Waveguide is made with the conductive plate 30 at the point 60. Here, the inner conductor by means of a dielectric Socket, preferably PTFE socket, centered between the conductive plates 20 and 30 through the aperture 70 within the conductive plate 20 out. The PTFE socket is called Cylinder jacket with a length of 4.8 +/- 0.1 mm, whose Outside diameter with 1.4 - 0.1 mm and its inside diameter over a length of 3.8 - 0.1 mm with 1.4 mm as well as over a Measured length of 1 mm with an inner diameter of 2.2 mm become. The outer conductor of the signal coupler coaxial The waveguide is with the surface parallel to the plate 30 arranged conductive plate 20 in the immediate vicinity the aperture 70 coupled.

Another embodiment of the invention for a Planar antenna for the frequency range between 890 MHz and 960 MHz show FIGS. 5 and 6. Corresponding to FIG. 1 a conductive metallic plate 20` with circular Edge and the diameter of 90 mm over a distance of 4.8 mm with a second conductive metallic plate 30`, which is designed as a circular section, parallel to the surface coupled, the centers of both the full circle area as well as the circular section area on an identical axis be arranged and according to Figure 6, the conductive plate 30 'in a line parallel to the tendon with four circular apertures 10 is provided and at three points 50`, one of the three points 50` on the in the plane of Circular section surface running symmetry line 15 of the arrangement is positioned with the conductive plate 20` conductive is coupled by conductive connecting elements 5 according to 11 at the position marked in FIG. 5 between the conductive plate 20 'and the conductive plate 30 'are introduced. For the purpose of mechanical stabilization between the conductive plate 20 'and the conductive plate 30 'a positioned on the line of symmetry of the arrangement Support cylinder 9 according to Figure 10 with a diameter of 6 mm introduced. The galvanic coupling of the inner conductor of the Coupling coaxial waveguide is done with the conductive Plate 30 'at point 60'. Here, the inner conductor is by means of a dielectric socket, preferably a PTFE socket, centrically between the conductive plates 20` and 30` as well as through the aperture 70` within the conductive plate 20` guided. The PTFE bushing is used as the cylinder jacket Length of 4.8 +/- 0.1 mm executed, the outer diameter with 1.4-0.1 mm and its inside diameter over a length of 3.8-0.1 mm with 1.4 mm and over a length of 1 mm with a Inner diameter of 2.2 mm. The outer conductor of the signal-coupling coaxial waveguide is with the Conductive plate arranged parallel to the surface of the plate 38 ' 20` coupled in the immediate vicinity of the aperture 70`.

Another exemplary embodiment is shown in FIGS. 7 to 9. According to FIGS. 7 to 9, a low-loss and low dielectric structure carrier 11 preferably Polypenco Q 200.5, polycarbonate or polystyrene, with a diameter of 93 mm and a base height of 5 mm on one side closed conductive layer 12, preferably consisting of Copper or aluminum with a layer thickness between 5 mm and 800 um, by means of additive or subtractive techniques, preferably subtractive techniques.

On the closed and conductive surface 12 opposite side of the dielectric carrier 11 8 shows a surface segment 13 with a conductive Layer, preferably consisting of copper or aluminum Layer thickness between 5 .mu.m and 800 .mu.m, occupied, the generated conductive layer 13 on the straight extending boundary edge 14 of the conductive layer opposite outer edge 18 of the conductive Surface segment 13 according to Figure 9 conductive with the closed conductive surface 12 is connected. The Power is supplied by contacting a coaxial Wave conduction by the point 16 according to FIG. 8 Inner conductor of the coaxial waveguide with the wave impedance of preferably 50 ohms with the surface segment 13 conductive is connected and the outer conductor of the coaxial waveguide with the opposite, closed and conductive full circular layer 12 is connected, the Inner conductor of the coaxial waveguide through a electromagnetic aperture 17 in the form of a circular Opening within the conductive layer 12 with the Diameter of 3.2 times the inner conductor diameter of the coaxial waveguide is guided.

Figure 10 shows a support cylinder 9 from a conductive material. In Figure 11 is an electrically conductive Connecting element 5 for connecting the points 50, 50` according to the Figures 3 to 6 shown.

Figures 12 to 15 show different possible embodiments or edge forms of the invention Planar antenna, whereby the special choice of the angle ϕ or ϕ` in Figures 14 and 15, the type of frequency response and the frequency range is adjustable. So the figure shows 12 that at an angle of ϕ between 0 and 90 degrees a polygon, the borders 8 by means of punctiform Fasteners at points 50 conductive to each other in Connection can be. FIGS. 14 and 15 show that the number and shape of the electromagnetic apertures 10 is also freely selectable.

FIGS. 16 and 17 each show a side view of the Planarantenna according to the invention, wherein the lateral edge of the dielectric carrier material L with strip-shaped Connecting elements 19 is occupied, so that at these points the two conductive layers 12 and 13 together in Are connected. FIG. 17 shows a side view of the according to Figures 1 and 2 explained planar antenna, the two conductive layers 12 and 13 over a length of L1 are connected via the conductive connecting element 19.

Reference symbol list:

1

Planar antenna

2.20.20 '

first senior schichc

3.30.30 '

second conductive layer

4.40.40 '

Tendon or boundary edge

5.19

Connection element or short-circuit elements

6,60,60 '

Feed point of the second conductive layer

7,70,70 '

electromagnetic aperture
(Diameter of 70 equals 2.1 mm -0.1)

8th

The tendon 4 facing away from the border

9

Support cylinder (diameter equal to 1.0 mm)

10th

Apertures in the second conductive layer

11

dielectric carrier

12th

first conductive surface (Fig. 7-9)

13

conductive surface segment (Fig. 7-9)

14

Tendon or boundary edge

15

Axis of symmetry

16

Feed point of the area segment 13

17th

electromagnetic aperture

18th

the tendon 4 opposite outer edge

80

Plumb line 4, 14, 40, 40 '

50, 50 '

Connection points (diameter = 1.5 mm)

A

Distance equal to 11.0 mm

B

Distance equal to 15.0 mm

R

Radius equal to 45.0 mm -0.2

R`

Radius equal to 42.0 mm

R1

Radius equal to 7.0 mm

Claims (16)

1. Planar aerial (1), in particular for the mobile radio telephone service, wherein the planar aerial (1) has two conductive layers with predefined mutual spacing, wherein the conductive layers are plates (2, 12, 20, 20'; 3, 13, 30, 30') or foils having faces parallel to one another, and the first layer (2, 12, 20, 20') has a face which is symmetrical about an axis of symmetry (15) and the second layer (3, 13, 30, 30') is a portion of the face of the first layer, wherein the second layer is formed by reducing and cutting off or omitting a part of the first face along a straight line (4, 14, 40, 40') extending at right angles to the axis of symmetry (15), and the line of the second layer forms a rectilinear edge, and the two layers are conductively connected to one another, the conductive connection being made by means of connecting elements (5, 19) arranged at points or in the form of strips, at the margin (8, 18) of the layers turned away from the line (4, 14, 40, 40') or directly adjoining it, characterised in that the first layer (2, 12, 20, 20') and the second layer (3, 13, 30, 30') are formed with a circular margin and the circular margins of the two layers are congruent, the second layer being reduced in relation to the area of the first layer by a chordal portion, the chord corresponding to the line (4, 14, 40, 40').
2. Planar aerial (1) according to claim 1, characterised in that apertures (10) are arranged parallel to the line (4, 14, 40, 40'), the apertures (10) being formed by openings or windows in the second layer.
3. Planar aerial (1), in particular for the mobile radio telephone service, wherein the planar aerial (1) has two conductive layers with predefined mutual spacing, wherein the conductive layers are plates (2, 12, 20, 20'; 3, 13, 30, 30') or foils having faces parallel to one another, and the first layer (2, 12, 20, 20') has a face which is symmetrical about an axis of symmetry (15) and the second layer (3, 13, 30, 30') is a portion of the face of the first layer, wherein the second layer is formed by reducing and cutting off or omitting a part of the first face along a straight line (4, 14, 40, 40') extending at right angles to the axis of symmetry (15), and the line of the second layer forms a rectilinear edge, and the two layers are conductively connected to one another, the conductive connection being made by means of connecting elements (5, 19) arranged at points or in the form of strips, at the margin (8, 18) of the layers turned away from the line (4, 14, 40, 40') or directly adjoining it, characterised in that apertures (10) are arranged parallel to the line (4, 14, 40, 40'), the apertures (10) being formed by openings or windows in the second layer.
4. Planar aerial (1) according to claim 3, characterised in that the first layer is circular, elliptical, triangular, square or hexagonal.
5. Planar aerial (1) according to one of claims 2 to 4, characterised in that the area of each aperture (10) is either circular, elliptical, rectangular, square, triangular, hexagonal or irregular.
6. Planar aerial (1) according to one of the preceding claims, characterised in that the planar aerial (1) is excited or supplied by a coaxial waveguide, the internal conductor of the waveguide being conductively connected to the second layer and the external conductor of the waveguide to the first layer, the internal conductor being arranged axially symmetrically to the aperture margin and without a galvanic connection thereto through an aperture (7, 17, 70, 70') within the first layer.
7. Planar aerial (1) according to one of the preceding claims, characterised in that the conductive connection between the two conductive layers is made by closed conductive materials (19) having an extensive, preferably strip-shaped configuration.
8. Planar aerial (1) according to one of the preceding claims, characterised in that the layers are kept apart by non-conductive elements (9).
9. Planar aerial (1) according to one of the preceding claims, characterised in that a dielectric (11) is between the two layers.
10. Planar aerial (1) according to one of the preceding claims, characterised in that the planar aerial (1) consists of a dielectric plate-shaped carrier (11) which is coated in a structured and conductive manner and of which the coatings form the conductive layers (12, 13).
11. Planar aerial (1) according to one of claims 9 or 10, characterised in that the conductive connection between the two conductive layers is made by a closed conductive coating along the contacting length over the entire height of the dielectric carrier (11).
12. Planar aerial (1) according to one of the preceding claims, characterised in that the margins (8, 18) of the two layers connected to one another so as to be conductive in portions or at points are superimposed in an aligned manner.
13. Planar aerial (1) according to one of the preceding claims, characterised in that the margins (8, 18) of the two layers, connected to one another so as to be conductive in part, are straight at least in portions and are symmetrical about the axis of symmetry (15).
14. Planar aerial (1) according to one of the preceding claims, characterised in that the margin (8, 18) of the dielectric carrier (11) extends in the region of the conductive connection (5, 19) of the two conductive layers and the arrangement of the through-connection extends _- rectilinearly parallel to the margin, the two half lengths being at an angle ϕ to one another, excluding the angular values of 0 angular degrees and 90 to 359 angular degrees, measured between a half length and the axis of symmetry (15) of the planar aerial (1).
15. Planar aerial (1) according to one of the preceding claims, characterised in that the area of the second layer is a cut out segment or a portion of the area of the first layer.
16. Planar aerial (1) according to one of the preceding claims, characterised in that the length of the perpendicular (20) to the straight line or chord (4, 40, 40') of the second layer changes between the straight line or chord (4, 40, 40') and the margin (8, 18) turned away from the straight line or chord (4, 40, 40') starting from the axis of symmetry (15) in such a way that the planar aerial (1) can receive or transmit more than one frequency.

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