WO2012143179A1

WO2012143179A1 - Antenna device

Info

Publication number: WO2012143179A1
Application number: PCT/EP2012/054231
Authority: WO
Inventors: Heiko Braun; Matthias Hampe; Martin Pohlmann; Stephan Schulteis; Werner Soergel
Original assignee: Robert Bosch Gmbh
Priority date: 2011-04-20
Filing date: 2012-03-12
Publication date: 2012-10-26
Also published as: DE102011007782A1

Abstract

The invention relates to an antenna device (10), in particular for a handheld locating appliance, comprising an emitter unit (14) having at least three surface transmitters (16, 18, 20, 22), each provided with a first feed point (24) for radiating an electro-magnetic wave in a first polarization. According to the invention, at least one of the surface transmitters (16, 18, 20, 22) is provided with at least one second feed point (26) for radiating an electro-magnetic wave in a second polarization.

Description

description

The antenna device

State of the art

The invention relates to an antenna device according to the preamble of claim 1. In the document DE 10 2005 062 874 A1 is already an antenna device, in particular for a hand-held device, with a radiator unit comprising four surface radiators, each having a first feed point for emitting a electromagnetic wave in a first polarization have been proposed.

Disclosure of the invention

The invention is based on an antenna device, in particular for a handheld location device, with a radiator unit comprising at least three, advantageously at least four, surface radiators each having a first feed point for emitting an electromagnetic wave in a first polarization. It is proposed that at least one of the area radiators has at least one second feed point for emitting an electromagnetic wave in a second polarization. Advantageously, at least four of the area radiators each have at least one second feed point for emitting an electromagnetic wave in a second polarization. In addition, the antenna device could have a larger number of radiator units each having two or more feed points. Under a "radiator unit" is intended particular unit to be understood, which is intended to emit and / or receive an electromagnetic wave. The emitter unit preferably has at least one emitter which both transmits and receives the electromagnetic wave. Alternatively, the emitter unit could have a first emitter for sending and a second emitter for receiving. In particular, the emitter unit is intended to emit electromagnetic waves having a frequency between 500 MHz and 16 GHz, advantageously between 1 GHz and 8 GHz, and in particular less than -6 dB, preferably less than -10 dB, transmitted from one to the emitter unit Line to reflect. Advantageously, the emitter unit has an amplification greater than 3 dBi, particularly advantageously greater than 6 dBi, in at least part of the frequency range. In particular, a "surface radiator" is to be understood as a part of the antenna device which is intended to emit at least part of an electromagnetic wave and which has a ratio of one length to a width that is less than 8, preferably less than 6, more preferably less than 4. Preferably, the surface radiators unconnected with each other, ie in particular isolated from each other. Alternatively, the surface radiators could be connected to one another by capacitors, coils and / or walls advantageously, advantageously in places where a distance between the surface radiators is the lowest. The term "feed point" is to be understood in particular a point at which an electrical energy is applied to the surface radiator by means of a conductor during transmission and, in particular, from which electrical energy is derived by means of the conductor when receiving.

A "polarization" is to be understood to mean, in particular, an orientation of a change in an electrical component of the electromagnetic wave. <br/> <br/> [0006] The design of the antenna device according to the invention makes it possible to constructively provide an antenna with multiple polarizations, which provides a high antenna gain and low input reflections in a wide frequency range. In addition, the antenna device has a high mechanical stability.

In a further embodiment, it is proposed that the first polarization is aligned at least substantially orthogonal to the second polarization, thereby structurally simple an advantageously low coupling between the two polarizations can be achieved. Preferably, at least one area radiator, particularly preferably four surface radiators, emit at least part of the electromagnetic wave in a first operating state in the first polarization and in a second operating state in the second polarization. In particular, the phrase "at least substantially orthogonal" should be understood to mean that the two polarizations differ by more than 60 degrees, advantageously more than 75 degrees, particularly advantageously 90 degrees Alternatively, the surface radiators could emit a two differently circularly polarized electromagnetic wave In particular, the radiator unit has a coupling between the two polarizations which is less than -10 dB, advantageously less than -15 dB, particularly advantageously less than -20 dB.

Furthermore, it is proposed that at least one of the area radiators has an at least substantially circular radiator surface, whereby an advantageous adaptation in a wide frequency range is possible. At least three of the area radiators, particularly preferably at least four of the area radiators, preferably have an at least substantially circular radiator surface. A "radiator surface" is to be understood in particular as meaning a surface of the surface radiator which delimits the surface radiator in the direction of the main maximum of the antenna radiograph of the planar radiator "understood that the radiator surface to less than 40%, preferably less than 20%, deviates from a circular area. Alternatively, surface radiators could have other forms that appear reasonable to the skilled person for a frequency and bandwidth, but preferably rectangular, polygonal, oval, elliptical and / or square shapes. The emitter unit preferably has the same antenna characteristic in both polarizations. Alternatively, the emitter unit could have different antenna characteristics in both polarizations. For this purpose, the surface radiators preferably one of an im

Essentially circular radiator surface different radiator surface, in particular an oval or elliptical radiator surface, on. In a further alternative embodiment, different antenna characteristics could be achieved by different excitation of selected feed points, in particular with different amplitudes and / or phase angles. It is also proposed that the first feed point and the second feed point are arranged at least substantially orthogonal to one another on a plane of the area radiators with respect to a center of the area radiator, whereby structurally simple advantageous feeding of the surface radiators is possible. In particular, an advantageous decoupling can be achieved due to a large distance of the feed points. The phrase "with respect to a center of the area radiator orthogonal to one another" is to be understood in particular as meaning that a connecting line between the center of the area radiator and the first feed point and a connection line between the center of the area radiator and the first feed point have a mean between 60 degrees and Preferably, the feed points are spaced apart from straight lines connecting the centers of the individual area radiators and the center of all the area radiators, alternatively or additionally, the area radiator have a different number of feed points, in particular distributed uniformly around the center, but advantageously three, each including 90 degrees to the nearest feed point, or more preferably four feed points, each 90 degrees to m include the nearest feed point.

In addition, it is proposed that the radiator unit has a substrate on which the surface radiators are applied, whereby a particularly simple production of the radiator unit can be achieved. Alternatively, the free space could at least partially be adjacent to the surface radiators on one side facing away from the radiator surface. In particular, a "substrate" is to be understood as meaning a body with a surface which fixes the surface radiator Alternatively, the surface radiator could consist of a material which appears appropriate to a person skilled in the art, but advantageously of a punched sheet metal part in particular In this case, the surface radiator is preferably provided for high-frequency applications. such as Rogers 4350. Alternatively, the substrate could be made from a particularly inexpensive material such as FR4.

Furthermore, it is proposed that the antenna device has a feed unit which is at least provided to feed the emitter unit differentially, whereby an advantageous for a location transmission and reception characteristic can be achieved. A "supply unit" is to be understood in particular as a unit which is intended to transmit a signal originating from a signal generator to the emitter unit and / or to transmit a received signal in the direction of a signal evaluation unit Preferably, the feed unit converts an unbalanced output signal of the signal generator into an at least partially symmetrical signal for the differential feed of the emitter unit the supply unit and / or the supply unit at least one balun, in particular a balun, for balancing the unbalanced output signal of the signal generator .On the other hand, the radiator unit could be the unsymmetrical output Signal of the signal generator by means of a symmetrical

Essentially transform feed line into a differential signal. Preferably, the at least substantially differential signal has a differential signal component of at least 30%, advantageously at least 75%. In particular, the term "differential" is to be understood as meaning that the dispensing unit supplies the emitter unit with different, in particular opposite phase, signals in one operating state at a time of transmission Alternatively or additionally, the antenna device could comprise a feed unit which is at least provided for emitter unit - To feed renziell, in particular in order to achieve different advantageously adjustable antenna characteristics.

In an advantageous embodiment of the invention, it is proposed that the feed unit has at least one symmetrical feed line, whereby constructively the feed points can be advantageously contacted. Advantageously, the feed unit has at least three symmetrical feed lines, particularly advantageously at least four symmetrical feed lines. Under a "food In particular, a line is to be understood which runs from a plane spanned by the ground plane to a plane spanned by the area radiators Preferably, the symmetrical feed line is longer than 5 mm, particularly preferably longer than 10 mm directly connected

Feed line on a main extension, which is aligned perpendicular to a plane spanned by the surface radiators. A "symmetrical feed line" is to be understood as meaning in particular a line with at least two identically shaped conductors, Preferably the symmetrical feed line comprises two band-shaped conductors Preferably, the conductors are applied to two sides of a particularly low-loss substrate Preferably, the two conductors feed two different area radiators.

Furthermore, it is proposed that the feed unit has at least one feed line tapering for adaptation, whereby an impedance of a signal generator and / or a line between the signal generator and the feed unit, usually 50 ohms or 75 ohms, are structurally simply adapted to an impedance of the emitter unit can. The impedance of the emitter unit depends on its design and is usually greater than 75 ohms. In particular, the expression "tapering for adaptation" should be understood as meaning that the feed line has different cross sections on the plane defined by the ground plane and on the plane defined by the area radiators Preferably, a cross section of the feed line changes from the plane defined by the ground plane and The feed line preferably tapers from the plane spanned by the ground plane and to the plane defined by the area radiators Alternatively, the feed line could be designed as a lambda / 4 transformer, in particular with sections of different line widths / 4 transformer for a center frequency of the antenna device, for example between 4 and 5 GHz optimized.

It is further proposed that the antenna device comprises at least one mass body with a ground plane that is aligned parallel to a plane of the area radiators, whereby an antenna with an advantageously high Antenna gain and a favorable front-to-back ratio can be achieved. A "ground plane" should be understood to mean, in particular, a preferably planar extension of the electrically conductive mass body which is at least as large as the radiator surface of the surface radiators Preferably, the mass body is a layer which appears sensible to a person skilled in the art and / or a grid Preferably, however, the antenna device has, in addition to the first ground plane, at least one further ground plane, advantageously four ground planes, which are arranged laterally next to the surface radiators Advantageously, a surface of this ground plane facing the surface radiator is concave Preferably, these further ground areas extend at least between a plane spanned by the first ground plane and a plane spanned by the area radiators Advantageously, these further ground planes are directly on a housing of the handheld location device brought and / or at least partially formed by the housing. Alternatively or additionally, the hand-location device could have a coil which at least partially surrounds the emitter unit, the mass body and / or advantageously the feed unit. The coil is preferably intended to locate measuring objects inductively. In addition, the coil advantageously serves as a reflector and / or advantageously shields a part of the hand-held device against electromagnetic waves of the antenna device.

In addition, the invention is based on a hand-held device with an antenna device according to the invention. In particular, a device for determining at least one piece of information about a

Position of a distant, invisible and / or advantageously concealed arranged object to be understood. Preferably, the hand-held locating device is intended to locate an electrical line, a water pipe, a beam and / or another object in a wall, a ceiling and / or another fixed object.

Drawing Further advantages emerge from the following description of the drawing. In the

Drawing is an embodiment of the invention shown. The drawing, the description and claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Show it:

1 shows a hand-held device with an antenna device according to the invention,

Fig. 2, the antenna device of Figure 1 with a radiator unit, a

Supply unit and a supply unit in a perspective view,

3 shows the emitter unit and the feed unit of Figure 2 in a perspective view,

4 shows the radiator unit from FIG. 2 in a plan view,

FIG. 5 shows a side of the supply unit facing away from FIG. 2, FIG.

Fig. 6, the radiator unit, the feed unit and the supply unit

Figure 2 in a further perspective view and

7 shows a profile of an amplitude of a received signal of the antenna device from FIG. 1 with and without a measurement object.

Description of the embodiment

1 shows a handheld location device 12 with an antenna device 10 according to the invention, a computing unit 48, a display 50 and rollers 52. In one operation, an operator moves the handheld location device 12 by means of the rollers 52 via a body, not shown, in particular via a wall. The antenna device 10 transmits electromagnetic waves into the body and receives reflections from measuring objects arranged in the body, for example cables, water pipes and / or wooden beams. The arithmetic unit 48 determines a position and / or a distance of the measurement objects from the antenna device 10 and displays them on the display 50 depending on a traveled distance. The computing unit 48 evaluates a transit time, a polarization and / or an amplitude of the received reflections , FIGS. 2, 3 and 5 show the antenna device 10. The antenna device 10 has a radiator unit 14, a feed unit 36 and a feed unit 54. The radiator unit 14 comprises four surface radiators 16, 18, 20, 22 and a substrate 32. The surface radiators 16, 18, 20, 22 are as one on the

Substrate 32 applied electrically conductive layer formed. The four area radiators 16, 18, 20, 22 each have a first feed point 24 for the radiation of an electromagnetic wave in a first polarization and a second feed point 26 for the emission of an electromagnetic wave in a second polarization. For this purpose, the feed points 24, 26 are arranged on a plane of the surface radiators 16, 18, 20, 22 with respect to a center 30 of the surface radiator 16, 18, 20, 22, orthogonal to each other. The surface radiators 16, 18, 20, 22 have a circular radiator surface 28.

As FIG. 4 shows, center points 30 of the area radiators 16, 18, 20, 22 are arranged in such a way that they form corners of a square. The surface radiators 16, 18, 20, 22 are spaced less than 20 mm apart and have a diameter between 10 mm and 40 mm. The feed points 24, 26 of the surface radiators 16, 18, 20, 22 are arranged on straight lines which connect the centers 30 of the surface radiators 16, 18, 20, 22, in each case at an edge of the radiator surface 28. In each case two feed points which are mutually are arranged next to each other, form a pair of feed points.

The feed unit 36, when transmitting, excites the two feed points 24, 26 of the feed point pairs, each substantially differentially from each other. When transmitting with the first polarization, the feed points 24 of two opposite pairs of feed points are excited. When transmitting with the second polarization, the feed points 26 of the other two opposite pairs of feed points are excited. In a locate operation, the handheld location device 12 alternately transmits to one of the two polarizations and simultaneously receives on both polarizations. Alternatively, the handheld location device 12 could receive alternately on one of the two polarizations and only on the same or the other polarization.

The feed unit 36 feeds the feed points 24, 26 of the feed point pairs in each case substantially differentially. For this purpose, the food unit 36 has four symmetrical supply lines 38, 40, 42, 44, which are each connected to a feed point pair, by recesses in the substrate 32 of the radiator unit 14. The feed lines 38, 40, 42, 44 have two conductors 56. The conductors 56 are arranged on two opposite sides of a substrate 58. The feed lines 38, 40, 42, 44 taper to the

Adaptation between the supply line unit 54 and the radiator unit 14.

The feed unit 54 has a mass body with a ground surface 46, strip lines 60, solder pads 62 and a substrate 64. The ground surface 46 is arranged on a side of the substrate 64 facing the emitter unit 14 and aligned parallel to a plane of the surface emitters 16, 18, 20, 22. The strip lines 60 and the soldering surfaces 62 are arranged on a side of the substrate 64 facing away from the emitter unit 14. The solder pads 62 are conductively connected to each other by the ground plane 46. The solder pads 62 are provided with connectors, not shown, here U-FL connectors for

Coaxial cable to be connected. About the plug, the strip lines 60 are connected to a signal generator and a signal evaluation unit. The strip lines 60 connect the solder pads 62 to the feed unit 36. The strip line 60 has a characteristic impedance of 50 ohms. For this purpose, the supply line unit 54 recesses 66, through which the feed lines 38,

40, 42, 44 of the feed unit 36 are guided. The one conductor 56 of the feed lines 38, 40, 42, 44 is respectively connected to one of the strip lines 60, namely soldered. The other conductor 56 of the feed lines 38, 40, 42, 44 is respectively connected to the ground surface 46, namely soldered.

FIG. 7 shows a diagram of a reflection received during a localization. In this case, an amplitude 68 of the reflection over a distance traveled by the hand-held tracking device 12 to a body 70 is shown. A solid curve 72 shows a profile of the amplitude 68 in a body having only a Plexiglas plate. A dashed curve 74 shows a profile of the amplitude 68 in a measurement in which a body is arranged next to the plexiglass plate at a position 76. The body is designed as a 6 mm diameter metal bar. It has a minimum distance of about 30 mm to the antenna device 10.

Claims

Antenna device, in particular for a hand-held locating device (12), with a radiator unit (14) which comprises at least three surface radiators (16, 18, 20, 22), each of which has a first feed point (24) for radiating an electromagnetic wave in a first Have polarization, characterized in that at least one of the surface radiators (16, 18, 20, 22) has at least a second feed point (26) for radiating an electromagnetic wave in a second polarization.

Antenna device according to claim 1, characterized in that the first polarization is aligned at least substantially orthogonally to the second polarization.

Antenna device according to claim 1 or 2, characterized in that at least one of the surface radiators (16, 18, 20, 22) has an at least substantially circular radiator surface (28).

Antenna device according to one of the preceding claims, characterized in that the first feed point (24) and the second feed point (26) are on a plane of the surface radiators (16, 18, 20, 22), relative to a center point (30) of the surface radiators (16 , 18, 20, 22), are arranged at least substantially orthogonally to one another.

Antenna device according to one of the preceding claims, characterized in that the radiator unit (14) has a substrate (32) on which the surface radiators (16, 18, 20, 22) are applied.

6. Antenna device according to one of the preceding claims, characterized by a feed unit (36) which is at least intended to differentially feed the radiator unit (14).

7. Antenna device according to claim 6, characterized in that the feed unit (36) has at least one symmetrical feed line (38, 40, 42, 44).

8. Antenna device at least according to claim 6, characterized in that the feed unit (38, 40, 42, 44) has at least one feed line (38, 40, 42, 44) which tapers for adaptation.

9. Antenna device according to one of the preceding claims, characterized by at least one mass body with a ground surface (46) which is aligned parallel to a plane of the surface radiators (16, 18, 20, 22).

10. Hand-held locating device with an antenna device (10) according to one of the preceding claims.