Antenna device

Abstract

The invention relates to an antenna device having an emitter element for emitting and/or receiving electromagnetic signals. The emitter element includes at least one coupling point connected to a side of the emitter element, and implemented for capacitively coupling electromagnetic signals in and/or out.

Claims

1. An antenna device comprising: comprising an emitter element for emitting and/or receiving electromagnetic signals, wherein the emitter element comprises at least one coupling point, the coupling point being connected to a side of the emitter element, wherein the coupling point is implemented for capacitively coupling electromagnetic signals in and/or out, wherein said antenna device comprises a conductive pattern for conducting electromagnetic signals, and wherein the conductive pattern and the emitter element are capacitively coupled to each other via the coupling point, wherein the emitter element comprises at least one blade element, wherein the emitter element and the blade element are galvanically coupled to each other, wherein the blade element is arranged on the side of the emitter element, wherein the emitter element and the blade element form an angle with each other, and wherein the blade element comprises the coupling point, wherein said antenna device comprises at least one bridge element, wherein the bridge element is galvanically or capacitively coupled to a feeding point of the conductive pattern, wherein the bridge element and the emitter element are capacitively coupled to each other via the coupling point, wherein the antenna device comprises a carrier element, wherein the blade element is bent from the emitter element in the direction toward the carrier element, and wherein the coupling point is located at a free end of the blade element.

2. The antenna device as claimed in claim 1, wherein an intermediate medium is located in the area of the coupling point and wherein capacitive coupling is effected via the intermediate medium.

3. The antenna device as claimed in claim 1, wherein the emitter element is attached at a distance from the carrier element.

4. The antenna device as claimed in claim 1, wherein the emitter element is configured as a surface emitter.

5. The antenna device as claimed in claim 4, wherein the emitter element is implemented as a surface emitter exhibiting an outer contour in the form of an n-gon, and wherein n is a natural number larger than or equal to three.

6. The antenna device as claimed in claim 4, wherein the emitter element is implemented as a funnel-shaped surface emitter exhibiting a central dip.

7. The antenna device as claimed in claim 5, wherein the coupling point is arranged centrally in the area of a side of the n-gon of the emitter element.

8. The antenna device as claimed in claim 4, wherein the emitter element is implemented as a metal sheet.

9. The antenna device as claimed in claim 4, wherein the emitter element is implemented as a monopole.

10. The antenna device as claimed in claim 1, wherein the conductive pattern is mounted on the carrier element.

11. The antenna device as claimed in claim 1, wherein the carrier element has a ground surface area located thereon.

12. The antenna device as claimed in claim 1, wherein the emitter element comprises coupling points on several sides, and wherein the emitter element is capacitively coupled to the conductive pattern via at least one coupling point.

13. The antenna device as claimed in claim 12, wherein the emitter element is capacitively coupled to the conductive pattern via more than one coupling point.

14. The antenna device as claimed in claim 1, wherein the emitter element comprises four coupling points.

15. The antenna device as claimed in claim 14, wherein the emitter element is capacitively coupled to the conductive pattern via the four coupling points.

16. The antenna device as claimed in claim 12, wherein the emitter element is connected to a signal source via at least one coupling point.

17. The antenna device as claimed in claim 12, wherein the emitter element is connected to an open circuit via at least one coupling point, so that there is an open end.

18. The antenna device as claimed in claim 12, wherein the emitter element is connected to a short circuit via at least one coupling point.

19. An antenna device comprising: an emitter element for emitting and/or receiving electromagnetic signals, wherein the emitter element comprises at least one coupling point, the coupling point being connected to a side of the emitter element, wherein the coupling point is implemented for capacitively coupling electromagnetic signals in and/or out, wherein the antenna device comprises at least two emitter elements, and wherein the two emitter elements are coupled to each other, in particular capacitively or galvanically.

20. The antenna device as claimed in claim 19, wherein the two emitter elements exhibit different distances from the carrier element.

21. The antenna device as claimed in claim 19, wherein an emitter element of the two emitter elements comprises a recess and wherein another emitter element of the two emitter elements is arranged in the area of the recess.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the present invention will be detailed subsequently referring to the appended drawings, in which:

(2) FIG. 1 shows a spatial and partly transparent representation of a first implementation of an antenna device,

(3) FIG. 2 shows an enlarged cutout of the antenna device of FIG. 1,

(4) FIG. 3 shows a section through the antenna device of FIG. 1,

(5) FIG. 4 shows a further spatial and partly transparent representation of the first implementation of an antenna device,

(6) FIG. 5 shows several schematic diagrams for illustrating control of the antenna device,

(7) FIG. 6 shows several schematic diagrams for illustrating the geometry of the emitter element,

(8) FIG. 7 shows several schematic diagrams for illustrating capacitive coupling of an emitter element,

(9) FIG. 8 shows several schematic diagrams for illustrating the geometry of the blade elements,

(10) FIG. 9 shows a section through a second implementation of an antenna device,

(11) FIG. 10 shows a section through a third implementation of an antenna device,

(12) FIG. 11 shows a spatial and party transparent representation of a fourth implementation of an antenna device,

(13) FIG. 12 shows a further spatial and partly transparent representation of the fourth implementation of an antenna device,

(14) FIG. 13 shows an enlarged cutout of the antenna device of FIG. 11 and FIG. 12, and

(15) FIG. 14 shows a section through the antenna device of FIG. 11 and/or FIG. 12.

DETAILED DESCRIPTION OF THE INVENTION

(16) The present invention essentially includes an antenna element—specifically an emitter element—as part of the antenna device 1, which antenna element is fed via a novel capacitive form of coupling. Thus, the diameter may be reduced to clearly below half a wavelength of the electromagnetic signals to be emitted and/or to be received, while enabling lossless, or low-loss, impedance matching to clearly below 100 ohm, e.g. 50 ohm. Depending on the implementation, this is successful up to a quarter of the wavelength and below. In this context, it is also possible to dispense with the lossy matching elements, which in conventional technology have been used for matching emitters of less than half a wavelength. In addition, no large ground surface area and no reflector are necessary for suppressing the back reflection. As a result, the efficiency of the emitter element 4 in total is clearly reduced in conventional technology.

(17) The antenna device 1 is implemented, by way of example, for operation at 910 MHz, With exemplary dimensions (a square carrier element having an edge length of 175 mm, and a square emitter element having an edge length of 75 mm) and a height of 30 mm, the real part of the base impedance in the event of a purely galvanic coupling amounts to approx. 200 ohm.

(18) FIG. 1 shows a spatial representation of an antenna device 1 comprising a carrier element 2 and an emitter element 4. A ground surface area 10 is also located on the carrier element 2 here. It can be seen that the emitter element 4 has a quadrangular outer contour and exhibits a funnel-shaped dip. In total, the emitter element 4 is spaced apart from the carrier element 2 and is held, or carried, here by the four coupling points and/or by the four blade elements 6.

(19) The area circled in FIG. 1 is depicted on a larger scale in FIG. 2. What can be seen are the four blade elements 6, which are located on the sides 40 of the emitter element 4, which here is quadrangular, and which have coupling points 5 for capacitive coupling at their free ends 60. Four bridge elements 7 emanate from the carrier element 2 at the four feeding points 8. The bridge elements 7 and the blade elements 6 join at the coupling points 5, where they effect capacitive coupling.

(20) The section of FIG. 3 also shows how the emitter element 4 exhibits a central dip toward the carrier element 2. One can further see that the blade elements 6 and, thus, the coupling points 5 are located on the sides 40 of the emitter element 4, which here is quadrangular. Just like the emitter element 4, the blade elements 6 are implemented as metal sheets and are coupled, in particular galvanically, to the emitter element 4. In between the blade elements 6 and the bridge elements 7, an intermediate medium 9 is located in the coupling area 5 in each case, said intermediate medium 9 here being configured as a dielectric and therefore also having an impact on capacitive coupling and enabling fastening of the emitter element 4, at a defined distance, between the blade element 6 and the bridge element 7. In addition, the bridge elements 7 here are galvanically coupled, at the feeding points 8, to the conductive pattern on the carrier element 2. The blade elements 6 and the emitter element 4, or its outer border, form an angle 14, which here is a 90° angle. The blade elements 6 here face the carrier element 2 while also facing away from the upper side of the emitter element 4.

(21) The conductive pattern 3 in the form of conductive tracks on the carrier element 2 is shown in FIG. 4. The conductive pattern 3 is located below the emitter element 4 and on the opposite side of the ground surface area 10, i.e., below the carrier element 2. In an alternative implementation, the ground surface area 10 is located below the carrier element 2, and the conductive pattern 3 is located above the carrier element 2. In a multi-layer architecture, the ground surface area 10 or the conductive pattern 3 are located within any number of layered carrier elements 2. The bridge elements 7 or possibly existing elements which connect the conductive pattern 3 to the bridge elements 7 therefore project through the carrier element 2, depending on the implementation.

(22) FIGS. 1 to 4 thus show the novel capacitive coupling of the emitter element 4 by using the example of patch having four feeding points. By combining capacitive coupling and feeding at four suitably selected points of the emitter element 4 it is possible for the emitter element 4 to be readily matched to a desired impedance, frequently 50 ohm, without involving a large ground surface area 10 and/or a reflector.

(23) The coupling points 5 are located on the sides 40 of the emitter element 4. To this end, the blades (or blade elements 6) are mounted on the sides of the emitter element 4 and are bent downward. Four bridges—one bridge (e.g., bridge element 7) for each feeding point 8—project from the carrier circuit board 2 and are capacitively coupled to the blades 7 via an intermediate medium 9. Consequently, one may reduce the width of the coupling gap between the bridge 7 and the blade 6 while additionally enabling a defined distance between the bridge 7 and the blade 6. As an alternative to the dielectric material present between the bridge 7 and the blade 6, an air gap may also be provided. The emitter element 4 and/or the blade elements 6 may be fastened, by way of supplementation, to the bridges 7, e.g., they may be screwed to, plugged onto, bonded or soldered to the intermediate medium located between the bridge 7 and blade 6. Because of the width, height, and the distance of the coupling point 5, almost any kind of impedance matching is possible, which clearly simplifies development of the antenna element 1 since no lossy matching network is required.

(24) The shape of the emitter element 4 as well as the capacitive coupling points 5 generate high field strengths at the coupling points 5, where the major part of the supplied energy is concentrated. This forces the emitter 4 to have a broad electric aperture, as a result of which the lateral dimensions of the emitter 4 may be clearly reduced.

(25) Coupling via the coupling points 5 on the sides of the respective emitter element 4 may be configured differently. FIG. 5 shows several variants by way of example.

(26) What are shown are different implementations of the architecture, the description being from the left to the right:

(27) a) Different numbers of feeding and/or coupling points 5: There may be only one coupling point 5, several coupling points 5 or here, by way of example, up to four coupling points 5. The number of coupling points 5 may also exceed four. This depends on the geometry of the emitter element 4. In the implementations shown here, capacitive coupling takes place across all coupling points 5.

(28) b) With an oppositely located open circuit (LL, 12) or short circuit (KK, 13) and a connection to a voltage source 11, which here is also to serve as a signal source for the electromagnetic signals to be emitted. The points of contact alternatively are present on adjacent sides 40. The connections to an open circuit 12 and/or a short circuit 13 which are shown here are alternatively effected by means of capacitive coupling and/or by a capacitor (lumped component).

(29) c) Examples of linear polarization. The variants are as follows (from the left to the right): Linear polarization of the emitter element 4 across two mutually opposite capacitive coupling points 5 and the connection to a signal source 11. Dual linear polarization with four coupling points 5 and two signaling sources 11. Dual linear polarization with a short circuit 13 on a side of the emitter element 4 which is located opposite the coupling point 5 for coupling to a signal source 11. Alternatively, capacitive coupling and/or a capacitor (lumped component) is also used. Dual linear polarization with the open circuit 11.

(30) d) Circular polarization with four coupling points 5 and four signal sources 11.

(31) e) Dual circular polarization with four coupling points 5 and two signal sources 11 each of which comprises two feeding points 8. The feeding points 8 of a signal source 11 are contacted to adjacent coupling points 5, respectively.

(32) f) Elliptical polarization with three capacitive coupling points 5 and three signal sources 11.

(33) The emitter element 4 may be shaped or configured differently. By way of example, FIG. 6 shows some variants. What is shown is an n-gonal emitter element 4, respectively, whose outer contour is formed by the n-exon. n is a natural number larger than three.

(34) FIG. 7 shows variants comprising a monopole as an implementation of the emitter element 4. Moreover, different variants for coupling to bridge elements 7 are depicted. In some of the implementations, no blade elements are present, so that the emitter element 4 comprises the at least one coupling point directly on a side 40. The variants of FIGS. 7 a) to e) and l) comprise only the emitter element 4 and the bridge element 7. Variants of FIGS. 7 f) to k) comprise the emitter element 4, at least one blade element 5, and at least one bridge element 7.

(35) The following implementations are shown in FIG. 7;

(36) a) simple monopole 4 with coupling at the feeding substrate.

(37) b) monopole 4 comprising capacitive coupling to the bridge element 7 from the left,

(38) c) monopole 4 comprising capacitive coupling from the right,

(39) d) two monopoles 4 forming a dipole and being dually coupled in a capacitive manner,

(40) e) two monopoles 4 capacitively coupled to each other at the monopole ends and capacitively coupled to the bridge elements 6 via the coupling points 5, and

(41) f) short circuit of two capacitively coupled monopoles 4, which results in a dipole or patch. The laterally mounted blade elements 6 are angulated in the direction of the bridge elements 7 at an angle 14 of 90°.

(42) g) angulated monopole 4 (also comprising angulation 14) comprising capacitive coupling from the right to a bridge element 6,

(43) h) angulated monopole 4 comprising capacitive coupling from the left,

(44) i) monopole 4 (=dipole) that is dually coupled in a capacitive manner,

(45) j) dual capacitively coupled monopole 4 (=dipole) comprising capacitive coupling of the emitter elements,

(46) k) dual capacitively coupled monopole 4 (=dipole) comprising a capacitor (lumped component) between the emitter elements 4.

(47) Instead of monopoles in the form of wires or, coaxial cables, the emitter elements 4 are, in alternative implementations, surface emitters, e.g., in the form of broad metal-sheet elements. This is shown by FIG. 7 l), which allows a view, twisted by 90°, of the implementation of FIG. 7 b). The side 40 of the emitter element 4 here is defined by the floor space. The bridge element 7, which is configured as a strip here, is capacitively connected, on this side 40, to the emitter element 4 via the coupling point 5.

(48) The blade elements 6 on the emitter element 4 may also be implemented differently. FIG. 8 shows some variants by way of example (the descriptions are again from the left to the right):

(49) a) triangular blade element 6 comprising any internal angles <180°;

(50) b) n-gon with n≥3 up to a circular or elliptical blade element 6 or a shape that is similar to a T-piece (extreme right)

(51) c) blade elements 6 of any type of angulation whose connection to the emitter element—not shown here—would be at the right end in each case. The free ends 60 each have the coupling points located thereat, and the ends—which, depending on the implementation, are located opposite the free ends—have the blade elements 6 located thereat which are connected to the respective emitter element.

(52) Just like the blades 6 on the emitter element 4, the bridges 7 may also be configured differently. They may vary in width, height, thickness and shape. In addition, they may be straight or angulated. In addition to air, an intermediate medium 9, e.g., dielectrics, ferrites, ferroelectrics and others, may be inserted between the emitter element 4 and the feeding circuit board 2. Fastening of the bridge elements 7 on the feeding circuit board as an example of the carrier element 2 may be implemented differently, just like fastening of the emitter element 4 on the bridge elements 7, e.g., the bridge elements 7 may be screwed on, plugged, bonded or soldered.

(53) The illustrations FIG. 9 and FIG. 10 show two further embodiments comprising four points for capacitive coupling between the conductive pattern on the carrier element 2 and the emitter element 4.

(54) At the feeding points 8, respectively, capacitive coupling takes place between the conductive pattern on the carrier element 2 and the bridge elements 7. The blade elements 6 are located on the sides of the n-gonal emitter element 4 and are bent in the direction of the carrier element 2.

(55) In the implementation of FIG. 9, there is galvanic coupling between the bridge elements 7 and the blade elements 6 in the areas demarcated by circles and arrows. In this variant, the coupling points 5 for capacitive coupling are therefore located in the area of the feeding points 8. The blade elements 6 and the bridge elements 7 are galvanically coupled to one another or designed to be integral, depending on the implementation. In the latter variant, therefore, the blade elements 6 end up with their coupling points 5 on the free ends 60 on the carrier element 2.

(56) In the implementation of FIG. 10, there is capacitive coupling—here, in particular, via an air gap—between the bridge element 7 and the blade element 6, so that between same, there is also the capacitive coupling point 5. Capacitive coupling continues to exist between the bridge element 7 and the feeding point 8. This is in contrast to the galvanic coupling between the blade elements 6 and the emitter element 4. The blade elements 6 here may also be seen as sheet metal strips which are attached to the sides of the emitter element 4 and are bent downward. Also, one may see that across the implementations of blade elements 6 and bridge elements 7, the distance between the emitter element 4 and the carrier element 2 or, e.g., a ground surface area on the carrier element 2 is adjustable.

(57) In one implementation, the at least one emitter element 4 is made of sheet metal, the blade elements 6 and the bridge elements 7 also consisting of sheet metal.

(58) The illustrations of FIG. 11 to FIG. 14 show a further implementation of the antenna device 1 comprising two emitter elements 4, 4′. This is a “stacked patch”, for example, e.g. for dual-band design or for expanded broad-band design.

(59) FIG. 11 shows the two emitter elements 4, 4′, which are implemented differently and are both spaced apart from the carrier element 2. The emitter element 4 (also: first emitter element) which is located at a higher level comprises a quadrangular outer contour and a central quadrangular recess 21. Other outer contours are also possible. The second emitter element 4′ is located inside the recess 21 and is closer to the carrier element 2. In the implementation shown, the second emitter element 4′ is also configured to be quadrangular. Both emitter elements 4, 4′ are implemented to be planar here and are located essentially in parallel to the carrier element 2. One can recognize the conductive pattern 3 in the form of conductive tracks on the carrier element 2 having the four feeding points 8, to each of which a bridge element 7 is connected. This is in line with the four coupling points 5 at the blade elements 6 on the four outer sides 40 of the upper emitter element 4.

(60) In FIG. 12 one may see the different implementations of the two emitter elements 4, 4′ and their mutual arrangements. One can also see that the blade elements 6 are located on the sides 40 of the upper, or first, quadrangular emitter element 4 and project in the direction of the carrier element 2 from there. Therefore, the capacitive coupling points 5 are also located on the sides. One may also see the planar progress of the blade elements, which start from the sides of the upper emitter element 4 and are angulated here in the direction of the carrier element 2.

(61) FIG. 13 shows the enlarged cutout of the part of the antenna device 1 of FIG. 12. Tongue elements 15 project from the coupling points 5 to the emitter element 4′ which is located further in the direction of the carrier element 2, and therefore also generate electric here, in particular capacitive—coupling to said—second—emitter element 4′. In total, therefore, the two emitter elements 4, 4′ are capacitively coupled to each other, and one of the two emitter elements 4 is capacitively coupled to the conductive pattern 3 via the blade elements 6.

(62) The section of FIG. 14 once again shows that the upper—first—emitter element 4 rests on the carrier element 2 via the connection of laterally located blade elements 6 and bridge elements 7 and is capacitively coupled—via the coupling points 5—to the feeding points 8. A dielectric is interposed, as an intermediate medium 9, between the bridge elements 7 and the blade elements 6. The tongue elements 15, which also cause electric and, here, capacitive contacting, extend in the direction of the lower—second—emitter element 4′.

(63) Additionally, FIG. 14 has also plotted therein that the carrier element 2 has a width of 175 mm and that the upper emitter element 4 has a side length of 75 mm. The outer contour, which here is quadrangular, in particular, of the upper emitter element 4 is located about 25 mm above the carrier element 2.

(64) Capacitive coupling of at least one emitter element at—advantageously four—points provides the following advantages:

(65) a) The lateral dimensions of the emitter element may be clearly smaller than half the wave length at the operating frequency. Thus, dimensions of a quarter of the wavelength or less are possible.

(66) b) The effective aperture of the emitter element is larger than the lateral extension since the shape of the emitter and the associated position of the coupling points cause a high concentration of the energy, or field strength, at the coupling points.

(67) c) Simple, low-loss impedance matching is possible.

(68) d) Despite the small volume dimensions, it enables a large relative bandwidth, both for impedance matching and for the directional characteristic.

(69) e) No large ground area surface and/or reflector is required for reducing back reflection. The diameter of the ground surface area may be half a wavelength or smaller, for example.

(70) f) The emitter element may be designed to be very low in cost since no expensive substrates such as ceramics are required. In the simplest case, stamping and bending parts made of sheet metal (e.g. aluminum) are sufficient.

(71) g) Very small design height, which promotes utilization for flat antennas, e.g. for UHF RFID applications.

(72) One technical field of application is enabled, e.g., by UHF RFID antennas for utilization in logistics, production or automation. This includes, for example, gate passages and others including bulk reading (sensing of many transponders within a short time), automated stocktaking or identity checks (e.g. in health care). A further possibility of application is offered by mobile terminals for satellite or terrestrial mobile communication. Further applications are in the field of automotives and/or in the field of networking between vehicles or road users (so-called Car2X).

(73) The above-described embodiments merely represent illustrations of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be appreciated by other persons skilled in the art. This is why it is intended for the invention to be limited merely by the scope of the following claims rather than by the specific details presented herein by means of the descriptions and illustrations of the embodiments.

(74) While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations and equivalents as fall within the true spirit and scope of the present invention.

REFERENCES

(75) [1] A. E. Popugaev and R. Wansch, “A novel miniaturization technique in microstrip feed network design,” in Proc. of the 3rd European Conference on Antennas and Propagation, EuCAP 2009, Berlin, March, 2009, pp, 2309-2313. [2] A. E. Popugaev, R. Wansch, S. Urquijo, “A NOVEL HIGH PERFORMANCE ANTENNA FOR GNSS APPLICATIONS,” in Proc. of the 2nd Second European Conference on Antennas and Propagation (EuCAP), Edinburgh, UK, Nov. 11-16, 2007. [3] L. Weisgerber and A. E. Popugaev, “Muitibeam antenna array for RFID applications,” in Proc. of the 2013 European Microwave Conference (EuMC), Nuremberg, October 2013, pp. 84-87.