EP3440738B1 - Antenna device - Google Patents

Description

The invention relates to an antenna device. The antenna device is used in particular to transmit and / or receive electromagnetic signals.

The constant downsizing or miniaturization of electronic and electromechanical systems ultimately also necessitates the corresponding downsizing of the required components without losing performance. On the contrary, the aim is to increase the performance of these assemblies.

In addition, the need for wirelessly communicating components is increasing, and so is the need to reduce the size of the antennas as the core of these assemblies. This is one of the fundamental problems of the miniaturization of systems, because the development and ultimately the dimensions of the antenna elements required are subject to certain physical limits.

Antennas have different directional characteristics with different properties depending on their shape, size and power supply. There are a variety of antenna shapes to suit the amount of needs desired for the application. The supply or coupling of the signal source to the radiator element also plays a decisive role here, because in addition to the shape and size, the properties of the radiated wave and the base point impedance of the antenna are also determined. Such properties can e.g. B. Form of the radiation lobe, but also especially the polarization (linear, circular, elliptical), the polarization purity (polarization decoupling) and the omnidirectionality of the emitted free space wave. The impedance bandwidth and the frequency dependence of the directional characteristic are also decisive factors of an antenna for broadband wireless communication. In order to generate, for example, beamforming with group antennas that are as uniform and extremely similar as possible in different spatial directions, a high degree of polarization purity and omnidirectionality of the directional characteristic of the individual element is required.

For many applications, e.g. B. with UHF-RFID (Ultra-High-Frequency-radio-frequency identification-) reading gates, circularly polarized antennas are usually used to to reliably detect the mostly linearly polarized passive transponders even with very different orientations in the room. For this purpose, multi-lobe antennas are increasingly being used in order to cover a larger angular range or space with a large number of beam forms. This allows a large number of transponders, which are often arranged in bulk, to be reliably identified. In addition, such a multi-lobe antenna enables the position of the transponder in the room to be determined (localization). For this, very uniform and symmetrical beams are required, the generation of which is only possible through the mentioned radiation properties of the individual element of the group antennas.

For many applications the antennas have to be inexpensive. To z. B. to generate a circularly polarized directional characteristic inexpensively, a radiator element (usually in the form of a patch antenna) is often coupled to two feed points offset by 90 ° (see, for example, "Patch Antenna (Circular), 860-930 MHz" from Poynting Antennas (Pty.) Ltd.). This is done galvanically, for example, through wire lines below the patch. A feed network (mostly in microstrip line technology) is usually required here, which enables the phase shift of the power supplied by 90 °. However, the directional characteristic here has poor polarization purity or cross-polarization discrimination (XPD), which results in asymmetrical lobes in beamforming. This structure also means that the patch diameter must be on the order of half a wavelength and a large ground plane or a reflector are required in order to keep the reflection (cross-polarization) low. The bandwidth of such a structure is also very small.

Ceramic antennas can be used in order to be able to develop antennas with small dimensions and thereby generate a directional characteristic with high polarization purity and omnidirectionality. However, these are very expensive and generally very narrow-band. A more economical method is to excite the radiator element at four feed points, each offset by 90 ° [1]. It is advantageous to use a radiator as a sheet metal element with connection segments bent by 90 ° on the four sides and to solder it directly to the board; Feeding through wire elements is also conceivable [2]. This requires a compact and decoupled feed network [1], which provides the four phases, each offset by 90 °. Thanks to the four-point feed, the diameter of the radiator element can be reduced to well below half a wavelength and a high bandwidth can be achieved at the same time. The bandwidth is slightly larger compared to the two-point fed solution. However, there are lossy stubs required to adapt the radiator and to increase its bandwidth. Furthermore, a very large ground area is required compared to the dimensions of the radiator element in order to keep the reflection (cross-polarization) low. Compared to the idea described, the radiator element also has a significantly greater electrical overall height.

Another possibility of coupling the patch element is to couple the line-guided wave through slots in the ground plane (see [3]). A microstrip line (usually orthogonally) crosses the slot in the ground line. In order to enable a circular polarization of the wave, the method of two- or four-point feeding can also be used here. A patch is not absolutely necessary for this, but in both cases a reflector is required in order to reduce the reflection and thus also to increase the profit. The disadvantage is that the dimensions of the opposite feed points (slots) and the diameter of the patch are approximately half the wavelength of the signals that are transmitted or received.

In the methods described, the dimensions of the radiator element and the distances between the feed points are in the order of magnitude of half a wavelength. If these dimensions were to be reduced, the base point impedances of the radiator element would increase significantly in terms of amount: the smaller the radiator element, the greater the base point impedance. This makes impedance matching to 50 ohms or 100 ohms more difficult and is generally associated with high power losses due to the matching elements and a reduction in bandwidth. This makes a low-loss adaptation of radiator elements or, in the case of feed point spacings significantly smaller than half the wavelength (e.g. a quarter of the wavelength), almost impossible.

A patch antenna, in which a radiation surface is arranged on a dielectric substrate at a distance from a ground plane and is fed via conductive pins that extend through the dielectric substrate, is from the US 2014/0266963 A1 known.

The US 2015/0042513 A1 discloses a patch antenna in which a radiation patch is fed electromagnetically via probes which extend from corners of the radiation patch with increasing width towards the center of the radiation patch.

The US 2015/0214592 A1 discloses an antenna arrangement in which four columns are provided to couple a horizontal radiation unit to output ports of a feed network.

HU FUGUO ET AL, "Ultra-Wideband Dual-Polarized Patch Antenna With Four Capacitively Coupled Feeds", IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, IEEE SERVICE CENTER, PISCATAWAY, NJ, US, vol. 62, no.5, pages 2440 - 2449, May 5, 2014 , disclose a broadband patch antenna that is capacitively fed on four sides.

SOORYA R ET AL, "UWB microstrip patch antenna with flower shaped patch and cavity structure", 2016 INTERNATIONAL CONFERENCE ON WIRELESS COMMUNICATIONS, SIGNAL PROCESSING AND NETWORKING (WISPNET), IEEE, (March 23, 2016), pages 2080-2084 , disclose a microstrip patch antenna with a radiator that is fed via four capacitively coupled feeds.

The US 2015/0015447 A1 discloses an antenna in which a conical radiation element is galvanically connected to a ground plane via four conductive elements.

The US 2003/174098 A1 discloses a loop antenna that is capacitively fed on four sides.

The object of the invention is to propose an antenna device which allows miniaturization without significant losses in the radiation properties.

The invention achieves the object by means of an antenna device according to claim 1.

The antenna device has a radiator element for radiating and / or receiving electromagnetic signals. The radiator element has at least one coupling point. The coupling point is connected to one side of the radiator element. In addition, the coupling point is designed for capacitive coupling and / or decoupling of electromagnetic signals. In some of the following configurations, the coupling point is directly on one side of the radiator element available. Depending on the design, the side refers to the outer surface or the outer border of the radiator element. In alternative configurations, the radiator element is expanded on the at least one side by an element - a wing element - which carries the coupling point. Depending on the configuration, the at least one coupling point is thus located directly or indirectly - in particular via a wing element - on one side of the radiator element. The coupling point is an area via which electromagnetic signals are coupled into the radiator element for emission or via which signals received from the radiator element are decoupled from the radiator element.

The antenna device is a single antenna or is part of several individual radiators or a group antenna.

The radiator element is the part of the antenna device which is used for the actual emission or the actual reception of the electromagnetic signals.

If the radiator element has the coupling point directly on its side, in one embodiment a web element for the capacitive coupling opens at the level of the radiator element side.

In one configuration, the antenna device has a conductor structure for conducting electromagnetic signals. The conductor structure and the radiator element are capacitively coupled to one another via the coupling point. The conductor structure is z. B. formed from electrical lines or from conductor tracks on a semiconductor substrate. The connection between the radiator element and the conductor structure for transmitting the electromagnetic signals takes place capacitively and in particular free of galvanic coupling.

In one embodiment, the radiator element has at least one wing element. The radiator element and the wing element are galvanically coupled to one another. Furthermore, the wing element is arranged on the side of the radiator element. In addition, the radiator element and the wing element form an angle with one another and the wing element has the coupling point. In this embodiment, the coupling point is thus located indirectly via the wing element on the side of the radiator element. Depending on the design, the emitter element and wing element or possibly wing elements are in one piece executed or the wing element or the wing elements are connected to the radiator element.

In one embodiment, the wing element is made of an electrically conductive material, in particular a metal.

In one embodiment, the antenna device has a carrier element. In one embodiment, the conductor structure is at least partially applied to the carrier element. If, in one embodiment, the conductor structure consists at least partially of conductor tracks, then in a supplementary embodiment these conductor tracks are applied or produced on the carrier element. In one embodiment, the carrier element is, for example, a substrate on which the conductor structure - z. B. with thin-film or thick-film processes - has been applied.

In a further embodiment, the wing element is angled away from the emitter element in the direction of the carrier element. The wing element thus runs from the side of the radiator element in the direction of the carrier element. Furthermore, the coupling point is located at a free end of the wing element. The free end is the end of the wing element which faces away from the side of the radiator element and therefore also from the radiator element. The free end is therefore an end that is not connected to the radiator element.

In one embodiment, the radiator element is only capacitively connected to the conductor structure or to other structures. In an alternative embodiment, the radiator element has at least one galvanic coupling in addition to the at least one capacitive coupling.

In one embodiment, an intermediate medium is present in the area of the coupling point, the capacitive coupling taking place via the intermediate medium. In one embodiment, the intermediate medium is a dielectric and, alternatively, at least a non-conductor or an insulator. The intermediate medium influences the type of coupling and therefore also the further electrical properties of the antenna device. In a further embodiment, the intermediate medium is attached between two electrically conductive units, so that the capacitive coupling results. These two at least partially electrically conductive units are formed in one embodiment by a wing element and a web element.

In one embodiment, the radiator element is attached at a distance from the carrier element. The radiator element is located in this embodiment, for. B. above the carrier element. In one embodiment, the distance also has an effect on the radiation properties of the antenna device. In one embodiment, the mechanical fastening and the electrical coupling of the radiator element are implemented via the same components (e.g. wing element and / or web element).

In one embodiment, a distance between the radiator element and the carrier element is at least dependent on the wing element. In this embodiment, the distance between the radiator element and the carrier element is at least dependent on the configuration of the wing element and in particular on its geometric configuration. In an associated configuration, the wing element is at least part of a support structure which carries the steel element and thus also holds it at a distance from the support element.

In one configuration, the conductor structure is applied to the carrier element, so that in one configuration in conjunction with the aforementioned configuration, the radiator element is located at a distance above at least part of the conductor structure. In this embodiment, the conductor structure is thus at least partially covered or protected by the radiator element.

In a further embodiment, the antenna device has at least one web element. The web element is galvanically or capacitively coupled to a feed point of the conductor structure. Furthermore, the bar element and the radiator element are capacitively coupled to one another via the coupling point. In this refinement, the conductor structure has a feed point at which electromagnetic signals are thus extracted from the conductor structure or coupled into the conductor structure. A web element is galvanically or capacitively coupled to this at least one feed point. Finally, the bar element and the radiator element are capacitively coupled to one another via the coupling point. In one embodiment, the web element and the wing element couple capacitively with one another. In one embodiment, the coupling between the conductor structure and the radiator element therefore takes place indirectly via the web element and the wing element.

In one embodiment, a distance between the radiator element and the carrier element depends at least on the web element. In this embodiment, the bar element thus also serves at least partially as a carrier element for the radiator element. In one embodiment, the radiator element is fastened relative to the carrier element via the wing element or via the wing element and a web element. The wing element or the web element allow the electrical - and especially capacitive - connection between the radiator element and the conductor structure. In this embodiment, this is expanded to include corresponding mechanical properties that allow the wing element and / or the web element to carry the radiator element and thus to keep it at a predeterminable distance from the carrier element. The distance between the radiator element and the conductor structure or especially the carrier element - and possibly other components located thereon - can therefore be set in a targeted manner via the wing element or the bar or via the wing element and the bar element in order to achieve certain effects or properties of the radiation properties To achieve antenna device.

According to the invention, the radiator element is designed as a surface radiator. A surface radiator differs from the so-called linear radiators (or also linear antennas) in that conducted waves are converted into free space waves at a surface area and vice versa. Surface emitters are used, for example, as directional emitters. The surface emitters are thus determined by a surface that they span or cover.

In one variant, the radiator element is designed as a surface radiator with an outer contour in the form of an n-corner. Here n is a natural number greater than or equal to three. In this refinement, the surface radiator therefore has the outer contour of a triangle, a square or any other n-corner. In one embodiment, the outer contour relates to the projection of the radiator element onto the carrier element and therefore, in one embodiment, to the surface that is covered by the radiator element. In one embodiment, there is therefore at least one wing element in each case between the corners on the sides of the outer contour. In an alternative embodiment, the wing element is located between two corners on at least one side. The arrangement of the at least one coupling point or, depending on the configuration of the at least one wing element, takes place in one configuration in the middle on the assigned side.

In one variant, the radiator element is designed as a funnel-shaped surface radiator with a central depression. The radiator element is therefore not flat in this embodiment, but has a depression that makes it funnel-shaped. In one embodiment, the radiator element is designed in the sense of a horn antenna. In a further embodiment, the radiator element has at least one recess within its outer contour.

If the radiator element is designed as an n-gon with n sides between the corners, an embodiment provides that the at least one coupling point is arranged in the area of one side of the n-gon of the radiator element. In one embodiment, the coupling point is arranged centrally on one side of the n-gon. In a further refinement, n coupling points are present to match the n-cornered radiator element, each of which is arranged on one side of the surface radiator.

In one embodiment, the radiator element is designed as a sheet metal. A sheet has a significantly larger area than its height. Furthermore, the sheet preferably consists of an electrically conductive metal or metal mixture.

In one variant, the radiator element is designed as a monopole. A monopole or a monopole antenna is part of a dipole antenna (or half-wave dipole antenna) as a linear antenna. Such antennas have a linear current distribution in the antenna structure. The implementation involves, for example, an electrical conductor made of a metallic wire or a metallic rod that is thin compared to the wavelength. A monopole antenna (also quarter-wave radiator or ground plane antenna) is, for example, an antenna rod that is reflected, for example, by an electrically conductive surface and thus results in a half-wave dipole. In an alternative embodiment, the monopole is formed by a flat sheet metal, the coupling point then being located above or below the surface of the monopole.

In one embodiment, the radiator element is designed as a rod-shaped monopole. The coupling point is located along a longitudinal axis of the rod-shaped monopoly. ,

In one embodiment, the antenna device has a ground plane which, in a further embodiment, is located on the carrier element. The ground plane is connected to an electrical ground.

In one embodiment, the radiator element has coupling points on several sides. The radiator element is capacitively coupled to the conductor structure via at least one coupling point. In a further embodiment, the radiator element is capacitively coupled to the conductor structure via more than one coupling point. In one embodiment, the coupling points or the wing elements having the coupling points are each located on the sides of a radiator element having an n-angular outer contour.

In one embodiment, the radiator element has four coupling points. In an associated embodiment, the radiator element is capacitively coupled to the conductor structure via all four coupling points.

In a further embodiment, the coupling points are arranged symmetrically around the radiator element.

In one embodiment, the radiator element is connected to a signal source (e.g. in the form of a voltage source) via at least one coupling point. In one embodiment, the signal source serves as a signal source for an electromagnetic signal that is emitted via the radiator element.

In an alternative or supplementary embodiment, the radiator element is connected to an idle via at least one coupling point. The coupling via the coupling point takes place capacitively in each case. In the case of idling, therefore, no coupling to a consumer or an electrical resistor is provided via the coupling point. There is thus an open end.

In a further alternative or supplementary embodiment, the radiator element is connected to a short circuit via at least one coupling point.

In one embodiment, there are at least two radiator elements. In a further embodiment, these at least two radiator elements are coupled to one another, in particular capacitively or via a short circuit, that is to say galvanically.

One embodiment provides that the two radiator elements have different distances from the carrier element. The radiator elements are at different heights upset. In one embodiment, the radiator elements overlap - z. B. in the projection perpendicular to the carrier element - and are free from an overlap in an alternative embodiment.

In one embodiment, one of the two radiator elements has a recess which is located, for example, in the center of the radiator element designed as a surface radiator. In a further embodiment, the other radiator element is arranged in the region of the recess. In one embodiment, one radiator element corresponds to the recess of the other radiator element and, in addition to this, is located at a different height than the correspondingly associated recess in one embodiment. In the last-mentioned embodiment, a part of a radiator element has, as it were, been offset in height. The two radiator elements are preferably capacitively coupled to one another.

In a further embodiment, the radiator element has at least one bend. In this embodiment, the radiator element is z. B. designed more rod-shaped or more as a flat element and has an angled or kinked course at at least one point.

The antenna device according to the invention therefore results in the advantages of reducing the dimensions of the antenna device and thereby not or only slightly losing performance, such as radiation behavior with simultaneous impedance matching. Via the type of capacitive coupling and the components involved in it, radiation properties and an impedance matching can in particular also be specified or set in a targeted manner.

Fig. 1

eine räumliche und teilweise transparente Darstellungen einer ersten Ausgestaltung einer Antennenvorrichtung,

Fig. 2

einen vergrößerten Ausschnitt der Antennenvorrichtung der Fig. 1,

Fig. 3

einen Schnitt durch die Antennenvorrichtung der Fig. 1

Fig. 4

eine weitere räumliche und teilweise transparente Darstellungen der ersten Ausgestaltung einer Antennenvorrichtung,

Fig. 5

mehrere Prinzip-Skizzen zur Verdeutlichung der Ansteuerung der Antennenvorrichtung,

Fig. 6

mehrere Prinzip-Skizzen zur Verdeutlichung der Geometrie des Strahlerelements,

Fig. 7

mehrere Prinzip-Skizzen zur Verdeutlichung der kapazitiven Ankopplung eines Strahlerelements,

Fig. 8

mehrere Prinzip-Skizzen zur Verdeutlichung der Geometrie der Flügelelemente,

Fig. 9

einen Schnitt durch eine zweite Ausgestaltung einer Antennenvorrichtung,

Fig. 10

einen Schnitt durch eine dritte Ausgestaltung einer Antennenvorrichtung,

Fig.11

eine räumliche und teilweise transparente Darstellungen einer vierten Ausgestaltung einer Antennenvorrichtung,

Fig. 12

eine weitere räumliche und teilweise transparente Darstellungen der vierten Ausgestaltung einer Antennenvorrichtung,

Fig. 13

einen vergrößerten Ausschnitt der Antennenvorrichtung der Fig. 11 und Fig. 12 und

Fig. 14

einen Schnitt durch die Antennenvorrichtung der Fig. 11 bzw. Fig. 12.

In particular, there are a large number of possibilities for designing and developing the antenna device according to the invention. For this purpose, reference is made, on the one hand, to the claims and, on the other hand, to the following description of exemplary embodiments in conjunction with the drawing. Show it:

Fig. 1

a spatial and partially transparent representation of a first embodiment of an antenna device,

Fig. 2

an enlarged section of the antenna device of Fig. 1 ,

Fig. 3

a section through the antenna device of Fig. 1

Fig. 4

a further spatial and partially transparent representation of the first embodiment of an antenna device,

Fig. 5

several principle sketches to illustrate the activation of the antenna device,

Fig. 6

several principle sketches to illustrate the geometry of the radiator element,

Fig. 7

several principle sketches to illustrate the capacitive coupling of a radiator element,

Fig. 8

several principle sketches to clarify the geometry of the wing elements,

Fig. 9

a section through a second embodiment of an antenna device,

Fig. 10

a section through a third embodiment of an antenna device,

Fig.11

a spatial and partially transparent representation of a fourth embodiment of an antenna device,

Fig. 12

a further spatial and partially transparent representation of the fourth embodiment of an antenna device,

Fig. 13

an enlarged section of the antenna device of Fig. 11 and Fig. 12 and

Fig. 14

a section through the antenna device of Fig. 11 or. Fig. 12 .

The present invention essentially comprises an antenna element - specifically a radiator element - as part of the antenna device 1, which is fed via a novel capacitive coupling. As a result, the diameter of the electromagnetic signals to be emitted or received can be well below half a wavelength can be reduced and enables loss-free or low-loss impedance matching to significantly less than 100 ohms, e.g. B. 50 ohms. Depending on the design, this can be achieved up to a quarter of the wavelength and below. It is also possible here to dispense with the lossy adaptation elements required in the prior art for adapting radiators smaller than half a wavelength. In addition, no large ground plane or a reflector is required to suppress the reflection. As a result, the overall efficiency of the radiator element 4 drops significantly in the prior art.

The antenna device 1 is designed, for example, for operation at 910 MHz. With exemplary dimensions (square carrier element with 175 mm edge length and square radiator element with 75 mm edge length) and a height of 30 mm, the real part of the base point impedance amounts to approx. 200 ohms with a purely galvanic coupling.

The Fig. 1 shows a three-dimensional representation of an antenna device 1 with a carrier element 2 and a radiator element 4. A ground surface 10 is also located on the carrier element 2 here. It can be seen that the radiator element 4 has a square outer contour and descends in a funnel shape. The radiator element 4 is at a distance from the carrier element 2 and is held or supported here by the four coupling points or by the four wing elements 6.

The Indian Fig. 1 circled area is in the Fig. 2 shown larger. The four wing elements 6 can be seen, which are located on the sides 40 of the here rectangular radiator element 4 and have coupling points 5 for the capacitive coupling at their free ends 60. Four web elements 7 extend from the carrier element 2 at the four feed points 8. The web elements 7 and the wing elements 6 meet at the coupling points 5 and cause the capacitive coupling there.

In the cut of the Fig. 3 it can also be seen how the radiator element 4 lowers centrally towards the carrier element 2. It can also be seen that the wing elements 6 and thereby the coupling points 5 are located on the sides 40 of the radiator element 4, which is square here. Like the radiator element 4, the wing elements 6 are designed here as metal sheets and are in particular galvanically coupled to the radiator element 4. Between the wing elements 6 and the web elements 7 there is in each case an intermediate medium 9 in the coupling area 5, which is designed here as a dielectric and therefore also Has effects on the capacitive coupling and which enables the radiator element 4 to be fixed with a defined distance between the wing element 6 and the web element 7. Furthermore, the web elements 7 are galvanically coupled to the conductor structure on the carrier element 2 at the feed points 8. The wing elements 6 and the radiator element 4 or its outer border form an angle 14, which here is a 90 ° angle. The wing elements 6 face the carrier element 2 here and also face away from the top of the radiator element 4.

The conductor structure 3 in the form of conductor tracks on the carrier element 2 shows Fig. 4 . The conductor structure 3 is located below the radiator element 4 and on the opposite side of the ground plane 10, i.e. below the carrier element 2. In an alternative embodiment, the earth plane 10 is below and the conductor structure 3 is above the carrier element 2. In a multi-layer structure the ground plane 10 or the conductor structure 3 within any number of layered carrier elements 2. The web elements 7 or possibly existing elements that connect the conductor structure 3 to the web elements 7 therefore protrude through the carrier element 2 depending on the configuration.

The illustrations Figs. 1 to 4 thus show the novel capacitive coupling of the radiator element 4 using the example of a patch with four feed points. By combining a capacitive coupling and feeding at four suitably selected points of the radiator element 4, it is possible that the radiator element 4 can be easily adapted to a desired impedance, often 50 ohms, without a large ground plane 10 or without a reflector.

The coupling points 5 are located on the sides 40 of the radiator element 4. For this purpose, the wings (or wing elements 6) are attached to the sides of the radiator element 4 and are bent downwards. Four webs protrude from the carrier board 2 - one web (or web element 7) per feed point 8 - and couple capacitively with the wings 7 via an intermediate medium 9. This allows the width of the coupling gap between web 7 and wing 6 to be reduced and also enables a defined distance between web 7 and wing 6. As an alternative to the dielectric material between web 7 and wing 6, an air gap can also be provided. The radiator element 4 or the wing elements 6 can also be attached to the webs 7, for. B. screwed, plugged, glued or soldered to the intermediate medium between web 7 and wing 6. Almost any impedance matching is possible due to the width, height and spacing of the coupling point 5 possible, which significantly simplifies the development of the antenna element 1, since no lossy matching network is required.

The shape of the radiator element 4 and the capacitive coupling points 5 generate high field strengths at the coupling points 5, in which the majority of the energy fed in is concentrated. This imposes a wide electrical aperture on the radiator 4, as a result of which the lateral dimensions of the radiator 4 can be significantly reduced.

The coupling via the coupling points 5 on the sides of the respective radiator element 4 can be designed differently. Fig. 5 shows examples of some variants.

1. a) Unterschiedliche Anzahl von Speise- bzw. Koppelstellen 5:
   Es kann nur eine Koppelstelle 5, mehrere oder hier beispielhaft bis zu vier Koppelstellen 5 geben. Die Anzahl der Koppelstellen 5 kann auch größer als vier sein. Dies ist abhängig von der Geometrie des Strahlerelements 4. Bei den hier gezeigten Ausgestaltungen findet über alle Koppelstellen 5 eine kapazitive Kopplung statt.
2. b) Mit gegenüberliegenden Leerlauf (LL, 12) oder Kurzschluss (KK, 13) und einer Verbindung mit einer Spannungsquelle 11, die hier auch als Signalquelle für die abzustrahlenden elektromagnetischen Signale dienen soll.
   Die Kontaktierungen liegen alternativ an benachbarten Seiten 40 vor. Die hier gezeigten Verbindungen mit einem Leerlauf 12 bzw. einem Kurzschluss 13 erfolgen alternativ mit einer kapazitiver Kopplung bzw. Kondensator (konzentriertes Bauelement).
3. c) Beispiele für eine lineare Polarisation.
   Die Varianten sind (von links nach rechts):
   • Eine lineare Polarisation des Strahlerelements 4 über zwei einander gegenüberliegende kapazitive Koppelstellen 5 und der Verbindung mit einer Signalquelle 11.
   • Eine duale lineare Polarisation mit vier Koppelstellen 5 und zwei Signalquellen 11. Eine duale lineare Polarisation mit Kurzschluss 13 an einer Seite des Strahlerelements 4, die der Koppelstelle 5 für die Kopplung mit einer Signalquelle 11 gegenüberliegt.
   • Alternativ wird ebenfalls eine kapazitiver Kopplung bzw. ein Kondensator (konzentriertes Bauelement) verwendet.
   • Eine duale lineare Polarisation mit Leerlauf 11.
4. d) Eine zirkulare Polarisation mit vier Koppelstellen 5 und vier Signalquellen 11.
5. e) Eine duale zirkulare Polarisation mit vier Koppelstellen 5 und zwei Signalquellen 11, die jeweils zwei Speisestellen 8 aufweisen. Die Speisestellen 8 einer Signalquelle 11 sind dabei jeweils mit benachbarten Koppelstellen 5 kontaktiert.
6. f) Eine elliptische Polarisation mit drei kapazitiven Koppelstellen 5 und drei Signalquellen 11.

Different versions of the architecture are shown, the description being from left to right:

1. a) Different number of feed or coupling points 5:
   There can be only one coupling point 5, several or here, for example, up to four coupling points 5. The number of coupling points 5 can also be greater than four. This depends on the geometry of the radiator element 4. In the configurations shown here, capacitive coupling takes place via all coupling points 5.
2. b) With opposite open circuit (LL, 12) or short circuit (KK, 13) and a connection to a voltage source 11, which is here also intended to serve as a signal source for the electromagnetic signals to be emitted.
   The contacts are alternatively present on adjacent sides 40. The connections shown here with an open circuit 12 or a short circuit 13 are alternatively made with a capacitive coupling or capacitor (concentrated component).
3. c) Examples of linear polarization.
   The variants are (from left to right):
   • A linear polarization of the radiator element 4 via two opposing capacitive coupling points 5 and the connection to a signal source 11.
   • A dual linear polarization with four coupling points 5 and two signal sources 11. A dual linear polarization with a short circuit 13 on one side of the radiator element 4 which is opposite the coupling point 5 for coupling to a signal source 11.
   • Alternatively, a capacitive coupling or a capacitor (concentrated component) is also used.
   • A dual linear polarization with open circuit 11.
4. d) A circular polarization with four coupling points 5 and four signal sources 11.
5. e) A dual circular polarization with four coupling points 5 and two signal sources 11, each of which has two feed points 8. The feed points 8 of a signal source 11 are each contacted with neighboring coupling points 5.
6. f) An elliptical polarization with three capacitive coupling points 5 and three signal sources 11.

The radiator element 4 can be shaped or configured differently. Fig. 6 shows examples of some variants. In each case, an n-cornered radiator element 4 is shown, the outer contour of which is formed by the n-corner. Here n is a natural number greater than three.

The Fig. 7 shows variants with a monopole as a design of the radiator element 4. Furthermore, different variants for the coupling with web elements 7 are shown. In some of the configurations there are no wing elements, so that the radiator element 4 has the at least one coupling point directly on one side 40. The variants of the Fig. 7 a) to e) and l ) only have the radiator element 4 and the bar element 7. The variants of the Fig. 7 f) to k) have the radiator element 4, at least one wing element 5 and at least one web element 7.

1. a) einfacher Monopol 4 bei Kopplung am Speisesubstrat,
2. b) Monopol 4 mit kapazitiver Kopplung mit dem Stegelement 7 von links,
3. c) Monopol 4 mit kapazitiver Kopplung von rechts,
4. d) zwei Monopole 4, die einen Dipol bilden und zweifach kapazitiv gekoppelt sind,
5. e) zwei Monopole 4, die an den Monopolenden miteinander kapazitiv gekoppelt sind und über die Koppelstellen 5 kapazitiv mit den Stegelementen 6 gekoppelt sind und
6. f) Kurzschluss zweier kapazitiv gekoppelter Monopole 4, woraus sich ein Dipol oder Patch ergibt. Die seitlich angebrachten Flügelelemente 6, sind unter einem Winkel 14 von 90° in Richtung der Stegelemente 7 abgewinkelt.
7. g) gewinkelter Monopol 4 (also mit einer Abwinklung 14) mit kapazitiver Kopplung von rechts mit einem Stegelement 6,
8. h) gewinkelter Monopol 4 mit kapazitiver Kopplung von links,
9. i) zweifach kapazitiv gekoppelter Monopol 4 (=Dipol),
10. j) dualer kapazitiv gekoppelter Monopol 4 (=Dipol) mit kapazitiver Kopplung der Strahlerelemente,
11. k) dualer kapazitiv gekoppelter Monopol 4 (=Dipol) mit Kondensator (konzentriertes Bauelement) zwischen den Strahlerelementen 4.

Are shown in the Fig. 7 the following configurations:

1. a) simple monopole 4 when coupled to the feed substrate,
2. b) monopole 4 with capacitive coupling with the bar element 7 from the left,
3. c) Monopole 4 with capacitive coupling from the right,
4. d) two monopoles 4, which form a dipole and are capacitively coupled twice,
5. e) two monopoles 4 which are capacitively coupled to one another at the monopole ends and are capacitively coupled to the web elements 6 via the coupling points 5 and
6. f) Short circuit of two capacitively coupled monopoles 4, resulting in a dipole or patch. The laterally attached wing elements 6 are angled at an angle 14 of 90 ° in the direction of the web elements 7.
7. g) angled monopole 4 (i.e. with a bend 14) with capacitive coupling from the right with a web element 6,
8. h) angled monopole 4 with capacitive coupling from the left,
9. i) double capacitively coupled monopole 4 (= dipole),
10. j) dual capacitively coupled monopole 4 (= dipole) with capacitive coupling of the radiator elements,
11. k) dual capacitively coupled monopole 4 (= dipole) with capacitor (concentrated component) between the radiator elements 4.

Instead of monopoles in the form of wires or z. B. coaxial cables, in alternative configurations, the radiator elements 4 are surface radiators, e.g. B. in the form of wide sheet metal elements. This shows the Fig. 7 I) who have a 90 ° rotated view of the design of the Fig. 7 b) allowed. The side 40 of the radiator element 4 is given here by the base area. The web element 7, designed here as a strip, is located on this side 40 through the coupling point 5 in a capacitive connection with the radiator element 4.

1. a) dreieckförmiges Flügelelement 6 mit beliebigen Innenwinkeln < 180°;
2. b) n-Eck mit n ≥ 3 bis hin zu einem kreisförmigen oder elliptischen Flügelelement 6 oder einer Form ähnlich einem T-Stück (ganz rechts);
3. c) beliebig abgewinkelte Flügelelemente 6, deren Anbindung an das - hier nicht dargestellte - Strahlerelement jeweils am rechten Ende erfolgen würde. Auf den freien Enden 60 befinden sich jeweils die Koppelstellen und mit den - je nach Ausgestaltung den freien Enden gegenüberliegenden - Enden sind die Flügelelemente 6 mit dem jeweiligen Strahlerelement verbunden.

The wing elements 6 on the radiator element 4 can also be designed differently. Fig. 8 shows a few examples (description again from left to right):

1. a) triangular wing element 6 with any interior angles <180 °;
2. b) n-gon with n ≥ 3 up to a circular or elliptical wing element 6 or a shape similar to a T-piece (far right);
3. c) any angled wing elements 6, the connection of which to the radiator element - not shown here - would take place at the right end. The coupling points are located on each of the free ends 60 and the wing elements 6 are connected to the respective radiator element at the ends opposite the free ends, depending on the configuration.

Just like the wings 6 on the radiator element 4, the webs 7 can also be designed differently. These can vary in width, height, thickness and shape. They can also be straight or angled. In addition to air, an intermediate medium 9, e.g. B. dielectrics, ferrites, ferroelectrics and others. The fastening of the web elements 7 on the feeder board as an example for the carrier element 2 can be implemented differently like the fastening of the radiator element 4 to the web elements 7, e.g. B. screwed, plugged, glued or soldered.

The illustrations Figures 9 and 10 show two further embodiments with four points for capacitive coupling between the conductor structure on the carrier element 2 and the radiator element 4.

There is a capacitive coupling between the conductor structure on the carrier element 2 and the web elements 7 at the feed points 8. The wing elements 6 are located on the sides of the n-angular radiator element 4 and are bent in the direction of the carrier element 2.

In the design of the Fig. 9 there is a galvanic coupling between the web elements 7 and the wing elements 6 in the areas highlighted here with circles and arrows. The coupling points 5 for the capacitive coupling are therefore in this variant in the area of the feed points 8. The wing elements 6 and the web elements 7 are galvanically coupled to one another or are made in one piece, depending on the design. In the last variant, the wing elements 6 with their coupling points 5 quasi open onto the free ends 60 on the carrier element 2.

In the design of the Fig. 10 there is a capacitive coupling - here in particular via an air gap - between the web element 7 and the wing element 6, so that the capacitive coupling point 5 is also located between the two. There is still a capacitive coupling between the web element 7 and the feed point 8. This in contrast to the galvanic coupling between the wing elements 6 and the radiator element 4. The wing elements 6 can also be seen here as sheet metal strips that are attached to the sides of the radiator element 4 and are bent downwards. It can also be seen that, via the configurations of wing elements 6 and web elements 7, the distance between the radiator element 6 and the carrier element 2 or z. B. a ground plane on the carrier element 2 are adjustable.

In one embodiment, the at least one radiator element 4 is made from sheet metal, the wing elements 6 and the web elements 7 also being made from sheet metal.

The illustrations FIGS. 11 to 14 show a further embodiment of the antenna device 1 with two radiator elements 4, 4 '. This is, for example, a "stacked patch", e.g. B. for dual-band design or extended broadband design.

The Fig. 11 shows the two differently configured radiator elements 4, 4 ′, both of which are spaced apart from the carrier element 2. The radiator element 4 located higher (also the first radiator element) has a square outer contour and a central square recess 21. Other outer contours are also possible. The second radiator element 4 'is located within the recess 21 and closer to the carrier element 2. The second radiator element 4' in the illustrated embodiment is also designed to be square. Both radiator elements 4, 4 'are designed flat here and are here essentially parallel to the carrier element 2. The conductor structure 3 can be seen in the form of conductor tracks on the carrier element 2 with the four feed points 8, each of which is connected to a web element 7. This is done here to match the four coupling points 5 on the wing elements 6 on the four outer sides 40 of the upper radiator element 4.

The Fig. 12 shows the different configuration of the two radiator elements 4, 4 'and their arrangement with respect to one another. It can also be seen that the wing elements 6 are located on the sides 40 of the upper or first square radiator element 4 and protrude from there in the direction of the carrier element 2. The capacitive coupling points 5 are therefore also on the sides. The flat course of the wing elements can also be seen, which extend from the sides of the upper radiator element 4 and are angled here in the direction of the carrier element 2.

The Fig. 13 shows the enlarged section of the part of the antenna device 1 of FIG Fig. 12 . Tongue elements 15 protrude from the coupling points 5 to the radiator element 4 'located further in the direction of the carrier element 2 and therefore also generate an electrical - here in particular capacitive - coupling to this - second - radiator element 4'. Overall, the two radiating elements 4, 4 ′ are capacitively coupled to one another and one of the two radiating elements 4 is capacitively coupled to the conductor structure 3 via the wing elements 6.

The cut of the Fig. 14 shows once again that the upper - first - radiator element 4 rests on the carrier element 2 via the connection of laterally located wing elements 6 and web elements 7 and is capacitively coupled to the feed points 8 via the coupling points 5. A dielectric is located between the web elements 7 and the wing elements 6 as an intermediate medium 9. The tongue elements 15 run in the direction of the lower - second - radiator element 4 ′, which also effect electrical and, here, capacitive contact.

In addition, it is also applied that the carrier element 2 has a width of 175 mm and the upper radiator element 4 has a side length of 75 mm. The outer contour - here in particular square - of the upper radiator element 4 is located approximately 25 mm above the carrier element 2.

1. a) Die lateralen Abmessungen des Strahlerelements können deutlich kleiner als die halbe Wellenlänge bei der Arbeitsfrequenz sein. So sind Abmessungen von einem Viertel der Wellenlänge oder weniger möglich.
2. b) Die wirksame Apertur des Strahlerelements ist größer als die laterale Ausdehnung, da die Form des Strahlers und die damit verbundene Position der Koppelstellen eine hohe Konzentration der Energie bzw. Feldstärke an den Koppelstellen hervorruft.
3. c) Es ist eine einfache, verlustarme Impedanzanpassung möglich.
4. d) Es ermöglicht trotz der geringen Volumenabmessungen eine hohe relative Bandbreite, sowohl für die Impedanzanpassung als auch für die Richtcharakteristik.
5. e) Es bedarf keiner großen Massefläche und/oder Reflektors, um die Rückstrahlung zu reduzieren. Der Durchmesser der Massefläche kann beispielsweise eine halbe Wellenlänge oder kleiner sein.
6. f) Das Strahlerelement kann sehr kostengünstig aufgebaut werden, da keine teuren Substrate, wie Keramiken, erforderlich sind. Im einfachsten Fall sind bereits Stanzund Biegeteile aus Blech (z. B. Aluminium) ausreichend.
7. g) Sehr geringe Bauhöhe, was dem Einsatz für flache Antennen entgegenkommt, z.B. für UHF-RFID-Anwendungen.

The capacitive coupling of at least one radiator element to - preferably four - points offers the following advantages:

1. a) The lateral dimensions of the radiator element can be significantly smaller than half the wavelength at the working frequency. Dimensions of a quarter of the wavelength or less are possible.
2. b) The effective aperture of the radiator element is larger than the lateral extent, since the shape of the radiator and the associated position of the coupling points cause a high concentration of energy or field strength at the coupling points.
3. c) Simple, low-loss impedance matching is possible.
4. d) Despite the small volume dimensions, it enables a high relative bandwidth, both for the impedance matching and for the directional characteristic.
5. e) There is no need for a large ground plane and / or reflector to reduce the reflection. The diameter of the ground plane can be, for example, half a wavelength or less.
6. f) The radiator element can be constructed very inexpensively, since no expensive substrates such as ceramics are required. In the simplest case, stamped and bent parts made of sheet metal (e.g. aluminum) are sufficient.
7. g) Very low overall height, which is useful for flat antennas, e.g. for UHF RFID applications.

UHF RFID antennas for use in logistics, production or automation, for example, offer a technical field of application. These include, for example, gate passages with bulk reading (recording of many transponders in a short time), automated inventory or personal checks (e.g. healthcare). Another possible application is mobile terminals for satellite or terrestrial mobile communication. Further applications are in the automotive sector or in the area of networking vehicles or road users (so-called Car2X).

The embodiments described above are merely illustrative of the principles of the present invention. It is to be understood that modifications and variations of the arrangements and details described herein will be apparent to other skilled persons. It is therefore intended that the invention be limited only by the scope of protection of the following patent claims and not by the specific details presented herein with reference to the description and explanation of the exemplary embodiments.

Credentials:

1. [1] AE 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, Mar. 2009, pp. 2309 - 2313 .
2. [2] AE 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. [3] L. Weisgerber and AE Popugaev, "Multibeam antenna array for RFID applications," in Proc. of the 2013 European Microwave Conference (EuMC), Nuremberg, Oct. 2013, pp. 84 - 87 .

Claims (14)

1. Antenna device (1)
   comprising an emitter element (4) for emitting and/or receiving electromagnetic signals,
   wherein the emitter element (4) comprises at least one coupling point (5), the coupling point (5) being connected to a side (40) of the emitter element (4), and
   wherein the coupling point (5) is implemented for capacitively coupling electromagnetic signals in and/or out,
   said antenna device (1) comprising a conductive pattern (3) for conducting electromagnetic signals, and
   wherein the conductive pattern (3) and the emitter element (4) are capacitively coupled to each other via the coupling point (5),
   wherein the emitter element (4) comprises at least one blade element (6), wherein the emitter element (4) and the blade element (6) are galvanically coupled to each other,
   wherein the blade element (6) is arranged on the side (40) of the emitter element (4),
   wherein the emitter element (4) and the blade element (6) form an angle (14) with each other,
   wherein the blade element (6) comprises the coupling point (5),
   said antenna device (1) comprising at least one bridge element (7), wherein the bridge element (7) is galvanically or capacitively coupled to a feeding point (8) of the conductive pattern (3), and
   wherein the bridge element (7) and the emitter element (4) are capacitively coupled to each other via the coupling point (5),
   the antenna device (1) comprising a carrier element (2),
   wherein the blade element (6) is angulated away from the emitter element (4) in the direction of the carrier element (2), and the coupling point (5) is located at a free end (60) of the blade element (6), characterized in that the emitter element (4) is configured as a surface emitter.
2. Antenna device (1) as claimed in claim 1,
   wherein an intermediate medium (9) is located in the area of the coupling point (5) and wherein capacitive coupling is effected via the intermediate medium (9).
3. Antenna device (1) as claimed in claims 1 or 2,
   wherein the emitter element (4) is attached at a distance from the carrier element (2).
4. Antenna device (1) as claimed in claim 1,
   wherein the emitter element (4) is implemented as a surface emitter having an outer contour in the form of an n-gon, and
   wherein n is a natural number larger than or equal to three.
5. Antenna device (1) as claimed in claims 1 or 4,
   wherein the emitter element (4) is implemented as a funnel-shaped surface emitter having a central dip.
6. Antenna device (1) as claimed in claim 4,
   wherein the coupling point (5) is arranged centrally in the area of a side of the n-gon of the emitter element (4).
7. Antenna device (1) as claimed in any of claims 4 to 6,
   wherein the emitter element (4) is implemented as a metal sheet.
8. Antenna device (1) as claimed in any of claims 1 to 7,
   wherein the emitter element (4) comprises coupling points (5) on several sides (40), and
   wherein the emitter element (4) is capacitively coupled to the conductive pattern (3) via at least one coupling point (5).
9. Antenna device (1) as claimed in claim 8,
   wherein the emitter element (4) is connected to an open circuit (12) via at least one coupling point (5), so that there is an open end.
10. Antenna device (1) as claimed in claim 8,
    wherein the emitter element (4) is connected to a short circuit (13) via at least one coupling point (5).
11. Antenna device (1) as claimed in any of claims 1 to 10,
    wherein the antenna device (1) comprises at least two emitter elements (4, 4').
12. Antenna device (1) as claimed in claim 11,
    wherein the two emitter elements (4, 4') are coupled to each other, in particular capacitively or galvanically.
13. Antenna device (1) as claimed in claims 11 or 12,
    wherein the two emitter elements (4, 4') have different distances from the carrier element (2).
14. Antenna device (1) as claimed in any of claims 11 to 13,
    wherein an emitter element (4) of the two emitter elements (4, 4') comprises a recess (21) and wherein another emitter element (4') of the two emitter elements (4, 4') is arranged in the area of the recess (21).

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