WO2007073993A1

WO2007073993A1 - Antenna arrangement and use thereof

Info

Publication number: WO2007073993A1
Application number: PCT/EP2006/068672
Authority: WO
Inventors: Bert Jannsen
Original assignee: Robert Bosch Gmbh
Priority date: 2005-12-27
Filing date: 2006-11-20
Publication date: 2007-07-05
Also published as: CN101346854B; EP1969674B1; CN101346854A; DE102005062542A1; DE502006007801D1; JP2009521885A; EP1969674A1

Abstract

The invention relates to an antenna arrangement comprising a conductive cylinder (2) which is mounted on a conductive surface (1). Radial slits (3) are arranged in the front surface of the cylinder (2). The height of the cylinder (2), in the area which is smaller that half of the operational wave length, is selected in such a manner that the beam characteristics, in the area outside of the cylinder axis, has a higher antenna gain than in the area of the cylinder axis.

Description

description

title

Antenna arrangement and use

State of the art

The invention is based on an antenna arrangement consisting of a conductive cylinder which is placed on a conductive surface.

Especially for the reception of satellite services such as SDARS or GPS

Antennas advantageous, which are simple and compact. In addition, the beam characteristic, that is the antenna diagram, must be adjustable to the requirements of the various services. In general, patch antennas are used today, which can be made both compact and inexpensive, as well as the required for the satellite services polarization (left / right circular) can provide. The additional reception of vertically polarized signals at elevation angles between 0 ° and 10 ° usually fails in this type of antennas at a low gain.

The currently used antennas, such as patch antennas, have in the

They usually have the characteristics of having a maximum gain in the zenith (90 ° elevation), which drops rapidly to small elevation angles. In some systems, however, it makes sense to shift the maximum gain to smaller elevation angles (by 30 °), so that sufficient profit is available even in peripheral areas. This is useful, for example, in geostationary satellite systems, which are characterized by their

Trajectory their supply area can supply only at low elevation angle. These low elevation angles usually also result in reception problems in shaded areas such as cities or mountain regions. In order to still allow a reception, repeaters are used, which work in the same frequency range but use a different polarization (vertical). US Pat. No. 6,304,224 B1 discloses an antenna with a cuboid housing having a cross-slot structure in an outer wall. Opposite the cross-slot structure is located in a further outer wall, a folded resonance space, due to the folding an outer dimension is less than half of the operating wavelength can be achieved. This allows for high power radiation with precise circular polarization.

Disclosure of the invention

With the measures of claim 1, that is, on the conductive surface facing away from the end surface of the cylinder radial slots are provided, the segments formed by the radial slots or the slots themselves are fed individually, the height of the cylinder is less than half of the Operating wavelength selected so that the radiation characteristic in the area outside the cylinder axis has a higher antenna gain than in the range of the cylinder axis, it is possible to achieve a high antenna gain at low elevation angles between 0 ° and 10 °, especially in vertical polarization. Depending on the selected height of the cylinder, the gain in the elevation range can be adjusted so that it is raised at low elevation angles. On the other hand, the inventive

Antenna in addition to a left circular polarization also a high gain of the vertical components at very low elevation angles between 0 ° and 30 ° at the same port available. The dimensions of the antenna described below can be further reduced by constructing the antenna on a substrate with a high dielectric constant and / or surrounded by such a material.

drawings

With reference to the drawings, embodiments of the invention will be explained. Show it:

1 shows the structure of an antenna according to the invention with slots in the end face of the cylinder,

FIG. 2 shows the same antenna with representation of the current distribution, FIG. 3 shows a feed network for an antenna structure according to the invention,

FIG. 4 shows an ohmic coupling for exciting the antenna structure,

FIG. 5 a field coupling for excitation of the antenna,

FIG. 6 shows the dependence of the antenna diagram on the elevation angle for different cylinder heights in left circular polarization,

FIG. 7 shows the dependence of the antenna diagram on the azimuth angle in the case of left circular polarization,

FIG. 8 the dependence of the antenna diagram on the elevation angle with vertical polarization,

FIG. 9 shows an antenna according to the invention with slots extended over the edge of the cylinder,

10 shows an antenna arrangement according to the invention, in which the boundary of the

Cylinder overhanging the plane of the slots in the direction of radiation,

11 shows an antenna arrangement as in FIG. 10 with recesses in which the plane of the slots projects beyond the edge in the region of the slots, FIG.

FIG. 12 shows an antenna arrangement whose cylinder is filled with material-high relative permittivity,

FIG. 13 shows an antenna arrangement whose cylinder is filled and surrounded by material-high relative permittivity;

FIG. 14 shows an antenna arrangement with additional slot in the end face of the cylinder,

FIG. 15 shows an antenna arrangement with an additional slot in the cylinder jacket. Description of the invention

Figure 1 shows the structure of an antenna arrangement according to the invention. On a metallically conductive surface 1, a metallically conductive cylinder is placed or applied. This cylinder 2 has radial slots 3 on its end face remote from the conductive surface 1. In the embodiment of Figure 1, these slots 3 are formed as perpendicular to each other arranged rectangular Phillips, which extend from the central axis of the cylinder 2 to the outer boundary of the end face. The segments 4 formed by the slots 3 are fed individually. The feeding points 5 are close to the intersection of the slots, that is near the cylinder axis.

FIG. 2 shows the same antenna arrangement as FIG. 1 with additional representation of the current distribution, the intensity being recognizable by the gray scale.

The height of the cylinder is selected in the range smaller than half the operating wavelength so that the radiation characteristic in the area outside the cylinder axis, in particular at the outer edge, a higher antenna gain g than in the region of the cylinder axis. This has the advantage that the border of the cylinder

Gain at low elevation angles is influenced so that the elevation range of the antenna pattern can be adjusted.

FIGS. 6 and 7 show the antenna diagrams of various arrangements. An ideal adaptation was required. FIG. 6 shows this

Antenna diagram for left circular polarization as a function of the elevation angle Θ (azimuth angle Φ = 90 °) for different heights of the cylinder. FIG. 7 shows, for the case h = 9.1 mm, the antenna diagram as a function of the azimuth angle at an elevation angle of Θ = 20 ° (or 160 °). LHCP stands for the left-polarized portion and RHCP for the right-polarized portion. It can be clearly seen that the reduction of the height can increase the gain in the outer areas and decrease it in the zenith (Θ = 90 °). Overall, the concept has a low overall height of approx. 7mm. By contrast, the lateral dimensions are of the order of half a wavelength (λ / 2 = 64 mm). Possibilities for reducing both the lateral dimensions and the height exist z. B. in that a ceramic material 6 with a high dielectric constant is inserted into the cylinder, as FIG. 12 shows. Alternatively or additionally, the antenna structure can also be surrounded by a dielectric material 7 (FIG. 13). Another influencing variable is given by the fact that the slots 3 according to FIG. 9 can be extended into the edge region of the cylinder. In the area of the slots 3 can

Recesses 8 may be provided in the boundary. Also, an additional boundary 9 of the cylinder over the plane of the slots 3 is possible, so that the boundary of the cylinder 2 projects beyond the plane of the slots 3 in the emission direction. In the boundary 9, recesses 10 may also be provided in the region of the slots 3 (FIG. 11). By doing so, the elevation range of the antenna pattern can be manipulated to emphasize the gain in the peripheral areas of the antenna pattern. In addition, the concept is very simple and inexpensive executable. As shown in FIGS. 14 and 15, further, likewise rectangular slots can be arranged in the cylinder 2 in order to cover other frequency ranges and / or to excite polarizations. In Figure 14, an additional radial slot 11 is provided in the end face and in Figure 15, a slot 12 in the outer jacket. In FIG. 8, the gain g for vertical polarization over the elevation angle Θ is shown at azimuth angle Φ = 90 °. This signal can also be tapped off either at the port Pl shown in FIG. 3 or at the port P2 decoupled from the port P1. Clearly, the desired increase in the gain g to recognize smaller elevation angles.

The excitation of the antenna (Figures 1 and 2 show the excitation points 5) is realized by four quadrature signals by a feed network 13, as z. B. shown in Figure 3, generated. Here, the 4 signals are generated by using three 3 dB hybrids 1 - 3 in combination with a 90 ° detour line. In the case of reception reciprocally at the input (Figure 3: Port Pl), the receiving left circular polarized signal can be tapped. By varying the feed network 13 or exchanging the antenna inputs, right-circularly polarized fields can also be received with the same antenna structure. The terminating resistors are designated R in FIG.

The supply of the signals to the antenna structure can be carried out in various ways known from the literature. For example, the contact points 5 of a direct excitation are shown in FIG. In this case, according to FIG. 4, the signals are transmitted by means of lines 14 from the feed network 13 arranged below the conductive surface 1 isolated performed by the conductive surface 1 and the contact points supplied directly (ohmic contact). In addition to the slot width, the position of the excitation (FIG. 1: RA) can be used to set the antenna impedance. Furthermore, the input impedance of the antenna can be influenced by alternatively exciting the antenna by field coupling. In Figure 5, this field coupling is shown schematically by a plan view in more detail. The different hatchings indicate different heights (positions) within the cylinder. The field coupling is carried out by four open at the end lines 15, which extend perpendicular to these under the slots 3. Through coupling of the fields, the excitation takes place. By varying the line width and the length of the open lines 15 and the distance between the

Slots 3 and the lines 15, the input impedance of the antenna can be largely influenced. The arrows indicate the excitation of the cables. Between the line excitation and the line sections overlapping with the slots 3, matching elements 14, for example in the form of stubs, are shown in FIG. 5, which serve to adapt the antenna impedance to the line impedance. such

Matching elements can also be provided for direct coupling.

Claims

claims

1. Antenna arrangement consisting of a conductive cylinder (2) which is applied to a conductive surface (1) having the following features: on the conductive surface (1) facing away from the end face of the cylinder (2) radial slots (3) are provided The segments (4) formed by the radial slots (3) or the slots themselves are supplied individually, the height of the cylinder (2) is less than half of that in the region

Operating wavelength selected so that the radiation characteristic in the area outside the cylinder axis has a higher antenna gain than in

Area of the cylinder axis.

2. Antenna arrangement according to claim 1, characterized in that the supply takes place such that sets a circular polarization.

3. Antenna arrangement according to claim 1 or 2, characterized in that the slots (3) over the edge of the cylinder (2) are extended.

4. Antenna arrangement according to one of claims 1 to 3, characterized in that the boundary (9) of the cylinder (2) projects beyond the plane of the slots in the emission direction.

5. Antenna arrangement according to claim 4, characterized in that recesses (8) are provided in the boundary in the region of the slots (3).

6. Antenna arrangement according to one of claims 1 to 5, characterized in that the supply takes place such that instead of or in addition to the circular polarization sets a vertical polarization.

7. Antenna arrangement according to one of claims 1 to 6, characterized in that in the cylinder (2) further slots (11, 12) are provided for exciting a radiation in other frequency ranges and / or polarizations.

8. Antenna arrangement according to one of claims 1 to 7, characterized in that the slots (3, 11, 12) are formed rectangular.

9. Antenna arrangement according to one of claims 1 to 8, characterized in that two mutually perpendicular slots (3) are provided with a length of one cylinder diameter.

10. Antenna arrangement according to one of claims 1 to 9, characterized in that the feed points (5) of the segments (4) are connected via ohmic contacts with a feed network (13).

11. Antenna arrangement according to one of claims 1 to 10, characterized in that the slots (3) can be excited via field couplings.

12. Antenna arrangement according to claim 11, characterized in that for excitation of the slots (3) via field coupling coupling lines (15) are provided, which intersect the slits (3) to be excited.

13. Antenna arrangement according to one of claims 1 to 12, characterized in that for feeding from a single high frequency source of a feed network (13) under the conductive surface (1) is provided, which via ohmic contacts and corresponding feedthroughs in the conductive surface (1 ) is connected to the feed points (5) for each segment (4) and / or the coupling lines.

14. Antenna arrangement according to one of claims 10 to 13, characterized in that the feed network (13) for dividing the energy of the high-frequency source on the segments (4) and / or coupling lines for a desired radiation 3dB hybrid, optionally in combination with a 90 ° Detour line has.

15. Antenna arrangement according to one of claims 1 to 15, characterized in that the cylinder (2) is filled with and / or surrounded by a material having a relative permittivity of greater than 1.

16. The use of the antenna device according to one of claims 1 to 15, both for radiation and for reception, wherein 3dB hybrids are provided for the separation between transmit and receive paths.