EP0952625A2 - Antenna for several radio communications services - Google Patents

Abstract

For one radio service, the antenna has a roof capacitance (1) oriented perpendicular to an antenna conductor. For at least one further radio service, a slot (3) is formed in the conductive plate of the roof capacitance, with a polarization oriented parallel to the roof capacitance. The length of the slot is selected to create a suitable impedance bandwidth.

Description

The invention relates to an antenna for several radio services with the character of a dipole or monopole. Antennas of this type are known from DE 195 10 236 A1. The antenna described there has a capacitive surface 1 and an antenna conductor 4 oriented essentially perpendicular thereto. Together with the conductive base surface 2 and the coupling of the signals specified there via the coupling conductor 15, an antenna with a monopole character is thus formed, the polarization direction of which is essentially perpendicular to Roof capacity is given. By introducing slots into the roof capacitance, this acts in an electrically frequency-dependent manner, so that an antenna for several radio services results for monopole operation with polarization oriented perpendicular to the roof capacitance 1. Antennas of this type thus have the limitation of the polarization oriented perpendicular to the roof capacitance. The function of communication with several vertically polarized mobile terrestrial telephone radio services and one or more frequency communication with satellite radio services, which, whether linearly or circularly polarized, is mainly aimed at horizontal polarization, can be covered with an antenna according to the state of the art Technology not possible.

The object of the invention is therefore to design an antenna according to the preamble of claim 1 such that in addition to the antenna function for radio services with polarization perpendicular to the roof capacity, the antenna function for at least one further radio service with a polarization parallel to the roof capacity and thus a combined function for radio services with mutually perpendicular polarization planes.

This object is achieved in an antenna according to the preamble of claim 1 by the features specified in the characterizing part of this claim.

An antenna according to the invention has the advantage of covering a whole variety of terrestrial and satellite radio services with one component with correspondingly little effort. Compact ones can be used especially for mobile radio services Design vehicle antennas which, for example, the mobile phone services GSM in the D network (approx. 0.9 GHz) and E network (approx. 1.8 GHz) with vertical polarization and at the same time the satellite radio service for location detection (GPS radio service at approx. 1.5 GHz) ) with mainly horizontally and circularly polarized incident waves due to several satellites close to zenith. In contrast to the vertically polarized radio service with a zero of the directional diagram in the zenith, the GPS navigation service requires a circularly polarized antenna with a maximum reception in the zenith. This requirement can advantageously be met with little effort with an antenna according to the invention.

• Fig. 1a: Antenne mit dem Charakter eines Monopols nach der Erfindung mit flächigem, mit der Grundfläche verbundenem Antennenleiter 4, einer Dachkapazität 1 und darin befindlichem geschlossenem Lambda/2-Schlitz 3 mit Resonanz im Frequenzbereich des weiteren Funkdienstes mit zur Ebene der Dachkapazität paralleler Polarisation mit Anschlußpunkten 9a, 9b, mit unsymmetrischer Leitung 10 und Antennenanschlußstelle 13 für den weiteren Funkdienst und mit Ankoppelleiter 15 und Antennenanschlußstelle 14 für den ersten Funkdienst;
• Fig. 1b: Antenne wie in Fig. 1a, jedoch mit rohrförmigem Antennenleiter 4 mit unsymmetrischer Leitung 10 in dessem feldfreien Inneren und mit auf der leitenden Grundfläche 2 befindlicher Frequenzweiche 16, in welche die unsymmetrische Leitung 10 eingeführt ist und an welche der vertikal orientierte Antennenleiter 4 angeschlossen ist und mit getrennten Antennenanschlußstellen (14, 13) am Ausgang der Frequenzweiche;
• Fig.2: Antenne gemäß Fig. 1a, jedoch mit doppelseitig kaschierten Leiterplatten mit zwei offenen, ca. Lambda/4-langen Schlitzen 3 mit unterschiedlichen Längen für zwei weitere Funkdienste bei unterschiedlichen Frequenzen in der die Dachkapazität bildenden leitenden Fläche auf der einen Seite der Leiterplatte mit jeweils einem Anschlußpunkt 9a an eine Streifenleitung auf der anderen Seite der Leiterplatte (grau schattiert), deren Masseleiter durch die leitende Fläche 1 gegeben ist.
• Fig.3a: Antenne gemäß Fig.2, jedoch mit zwei gleichlangen zueinander unter einem Winkel 21 von ca. 90 Grad angeordneten Schlitzen 3 zur Ausbildung einer Funktion mit Zirkularpolarisation der Antenne in einem weiteren Frequenzbereich mit einer 90-Grad Hybridschaltung 17 am Ende der beiden unsymmetrischen Leitungen 10 und mit der Antennenanschlußstelle 13 und mit zwei zusätzlichen Schlitzen 22 zur Gestaltung der unterschiedlichen Resonanzfrequenzen der Monopolantennenfunktion für zwei erste Funkdienste (z.B. D-Netz, E-Netz) mit zur Dachkapazität vertikaler Polarisation;
• Fig.3b: Blockdiagramm einer Antenne wie in Fig.3a mit einem der weiteren Antennenanschlußstelle 13 vorgeschalteten Frequenzbandpaß 23 zum ausschließlichen Durchlaß der Signale für den weiteren Funkdienst (GPS) und einem rauscharmen Verstärker (24). Um das Seitenbandrauschen von Funkgeräten 28 des ersten Funkdienstes (GSM) im Empfangszweig des weiteren Funkdienstes (GPS) zu vermeiden, ist eine Bandsperre 26 an der Antennenanschlußstelle 14 für den Frequenzbereich des ersten Funkdienstes (GSM) vorgeschaltet;
• Fig.4 oben: Antenne gemäß Fig.2, jedoch für zwei erste Funkdienste (z.B. D-Netz, E-Netz) mit zur Dachkapazität vertikaler Polarisation mit zwei zusätzlichen Schlitzen 22 zur Gestaltung der unterschiedlichen Resonanzfrequenzen der Monopolantennenfunktion und zwei Schlitzen 3 für den weiteren Funkdienst (z.B. GPS) unter 90 Grad. Mit Hilfe der Kontourkerben 18 werden die wirksamen Schlitzlängen und die Dachkapazität weitgehend unabhängig voneinander für die verschiedenen Frequenzbereiche abgeglichen. Fig. 4 unten: Flächiger, vertikal orientierter Antennenleiter 4 als Träger der Mikrostreifenleitungen für den weiteren Funkdienst;
• Fig. 5: Vertikales Richtdiagramm einer Antenne nach Fig. 4 im GPS-Frequenzband bei zirkularer Polarisation. Als Bezugsantenne wurde eine IEEE Standard Gain Antenne mit an das GPS-Frequenzband angepaßten geometrischen Abmessungen verwendet.

Exemplary embodiments of the subject matter of the invention are described below with reference to the drawings. It shows:

• 1a: Antenna with the character of a monopoly according to the invention with a flat antenna conductor 4 connected to the base, a roof capacitance 1 and a closed lambda / 2 slot 3 therein with resonance in the frequency range of the further radio service with polarization parallel to the roof capacitance level with connection points 9a, 9b, with asymmetrical line 10 and antenna connection point 13 for the further radio service and with coupling conductor 15 and antenna connection point 14 for the first radio service;
• Fig. 1b: Antenna as in Fig. 1a, but with a tubular antenna conductor 4 with asymmetrical line 10 in its field-free interior and with the crossover 16 located on the conductive base 2, into which the asymmetrical line 10 is inserted and to which the vertically oriented antenna conductor 4 is connected and with separate antenna connection points (14, 13) at the output of the crossover network;
• Fig. 2: Antenna according to Fig. 1a, but with double-sided laminated circuit boards with two open, approximately lambda / 4-long slots 3 with different lengths for two further radio services at different frequencies in the conductive surface forming the roof capacity on one side of the Printed circuit board, each with a connection point 9a to a strip line on the other side of the printed circuit board (shaded gray), the ground conductor of which is given by the conductive surface 1.
• 3a: Antenna according to FIG. 2, but with two slots 3 of equal length to one another at an angle 21 of approximately 90 degrees to form a function with circular polarization of the antenna in a further frequency range with a 90-degree hybrid circuit 17 at the end of the two unbalanced lines 10 and with the antenna connection point 13 and with two additional slots 22 for designing the different resonance frequencies of the monopole antenna function for two first radio services (eg D-network, E-network) with vertical polarization to the roof capacity;
• 3b: block diagram of an antenna as in FIG. 3a with a frequency bandpass 23 connected upstream of the further antenna connection point 13 for exclusive transmission of the signals for the further radio service (GPS) and a low-noise amplifier (24). In order to avoid the sideband noise of radio devices 28 of the first radio service (GSM) in the reception branch of the further radio service (GPS), a bandstop 26 is connected upstream of the antenna connection point 14 for the frequency range of the first radio service (GSM);
• 4 above: antenna according to FIG. 2, but for two first radio services (for example D network, E network) with vertical polarization to the roof capacity with two additional slots 22 for designing the different resonance frequencies of the monopole antenna function and two slots 3 for the further one Radio service (e.g. GPS) below 90 degrees. With the help of the contour notches 18, the effective slot lengths and the roof capacity are compared largely independently of one another for the different frequency ranges. 4 below: Flat, vertically oriented antenna conductor 4 as a carrier of the microstrip lines for the further radio service;
• Fig. 5: Vertical directional diagram of an antenna according to Fig. 4 in the GPS frequency band with circular polarization. An IEEE standard gain antenna with geometric dimensions adapted to the GPS frequency band was used as the reference antenna.

Fig. 1a shows an antenna with the character of a monopoly with a flat antenna conductor 4, which is conductively connected to both the roof capacitance 1 and the base. Due to the inductive effect of the antenna conductor 4 and the capacitive effect of the roof capacitance, a resonance is formed in the frequency range of a first radio service.

A resonant monopole antenna of low overall height with polarization perpendicular to the roof capacitance can thus be formed. The coupling to this resonant monopoly takes place via the coupling conductor 15 to form the first antenna connection point 14 Slot 3 introduced with resonance in the frequency range of the further radio service. Likewise, a slot open at one end with an approx. Lambda / 4 length can be designed. Appropriately chosen connection points 9a and 9b opposite one another on the edges of the slot at a distance 25 from the closed slot end allow the desired antenna impedance and the width of the slot to design the desired bandwidth. With the help of an unbalanced line 10 connected to the connection points 9a, 9b, which is electrically ineffective with regard to the monopole function of the antenna and is conducted parallel to the conductive surfaces of the roof capacitance 1 and the antenna conductor 4, the connection between the connection points 9a, 9b is connected to that at the conductive base 2 located further antenna connection point 13 is made.

FIG. 1b also shows an antenna with a monopoly character, as in FIG. 1a, but with a tubular antenna conductor 4. The asymmetrical line 10 is guided in its field-free interior. The first antenna connection point 14 is formed at the lower end of the antenna conductor 4 with the conductive base area 2. To lead out the antenna connection for the further radio service, a crossover 16 is formed in the base, inside which the continuation of the asymmetrical line 10 e.g. is designed as a high-impedance choke in the first frequency range and the antenna connection point 13 is designed without impairing the monopole function of the antenna.

2, in an advantageous embodiment of the invention, the roof capacitance 1 and the vertically oriented, flat antenna conductor 4 are designed as printed circuit boards laminated on both sides. The conductive surfaces are formed by the conductive material located on one side of the printed circuit boards and are electrically connected at the abutting edge. The asymmetrical line is designed as a strip line 10, the strip line being printed on the opposite side of the conductive surface 1 and the surface forming the ground conductor of the line 10. The connection between the stripline of the stripline 10 and the connection point 9a can be made in a simple manner by plated-through holes. Of the Connection point 9b is defined by the course of the strip conductor perpendicular to the slot direction as the point on the edge of the slot opposite point 9a. To illustrate the generality of the inventive concept, two slots 3 with different lengths and different polarization directions are shown in FIG. 2 within the two common polarization planes parallel to the roof capacitance with mutually separated asymmetrical lines 10 and further antenna connection points 13. As a result, several other radio services with different frequencies can be effected for the polarization level.

As a further advantageous embodiment of the invention, an antenna is shown in FIG. 3a, in which the conductive base is oriented horizontally and the monopole antenna is tuned for the frequency band of a terrestrial telephone radio service with vertical polarization as the first radio service and as a second radio service for a satellite radio service with essentially horizontal polarized incident waves is tuned.

Such an antenna is, for example, particularly suitable for combining the terrestrial GSM telephone service with the GPS satellite radio for use as a vehicle antenna with a horizontal conductive base area 2. Here, the roof capacity and the antenna conductor 4 oriented vertically for this purpose are dimensioned such that in the GSM frequency range There is resonance and the slot 3 is designed in length and width such that its resonance is suitable for receiving the GPS signals. In order to meet the requirement for maximum radiation in the zenith and the condition of circular polarization at the same time, there are two slots 3, each with two connection points and 9a, 9b, each with an asymmetrical line 10 connected to it, for the further radio service GPS with circular polarization. For this purpose, the slots in the conductive plate of the roof capacitance are oriented at an angle of almost 90 degrees to one another in such a way that the reception of the circularly polarized waves with the given direction of rotation is optimal. Both slots are implemented, for example, as lambda / 4-resonant slot lines with open ends at the edge of the roof capacity. The distance 25 of the connection points 9a, 9b from the closed end of the slot is chosen favorably in view of the characteristic impedance of the line connected to it. The other ends of the two lines are connected to the two inputs of a 90-degree hybrid circuit, in which one of the two received signals is changed in phase by 90 degrees and after a correctly polarized combination of the signals on Output of the hybrid circuit, the applicable circular polarization direction is present at the antenna connection point 13.

A particular advantage of the invention is that it can be easily implemented by using printed circuit boards for the production of the conductive surfaces and the lines. This technique enables a very good reproducibility of the fine-tuned structures in the manufacturing process. In this case, the roof capacitance 1 and the vertically oriented, flat antenna conductor 4 are designed as printed circuit boards which are conductively laminated on both sides, the conductive material located on one side of the circuit boards each forming the conductive surface. The asymmetrical line 10 is designed as a strip line, the strip line being printed on the opposite side of the conductive surface and the conductive surface forming the ground conductor of the line.

The advantage of the invention is also the relatively good decoupling between the antenna connection points 13 and 14. Because of the extremely large level differences between the transmitted GSM signals and the GPS signals to be received, it is advantageous to protect the sensitive GPS receiver from non-linear effects due to large To protect the signal level, the antenna connection point 13 to connect a bandpass 27 for this frequency range. In order to achieve good signal-to-noise ratios in the GPS range, it is also advantageous to add a low-noise preamplifier 24 without lossy leads. In order to avoid the sideband noise of GSM radio devices 28 in the GPS frequency range, it is advisable to connect a bandstop 26 to the antenna connection point 14.

In order to design an antenna function for an additional first radio service with a higher frequency and with polarization oriented vertically to the conductive base area, slots 22 can be introduced into the roof capacitance 1 in a manner known per se. Such an antenna for the two terrestrial mobile telephone services (D and E network) is shown in FIG. With the help of the notches 18, the slot lengths and the roof capacity for the design of the different resonance frequencies can be determined largely separately from one another.

With the antenna shown in FIG. 4, in addition to the radio services of the D and E network, the satellite navigation service GPS can also be received via a further connection point 13.

In contrast to the vertically polarized, first radio service with a zero of the directional diagram in the zenith, the GPS navigation service requires a circularly polarized antenna with a maximum of reception in the zenith. Therefore, two further slots, which are arranged at an angle of 90 ° to one another, are introduced into the conductive surface of the roof capacitance 1 and operated as λ / 4 slot antennas. The input impedance of the slots, which is effective for the edge current of the D network, is sufficiently low-resistance, since the slots have a strong resonance at 1,575 GHz, so that the radio antenna in the D network is not influenced.

The decoupling points of the two GPS slot antennas are put together as closely as possible and selected so that their impedance is 50 ohms. The RF signals of the GPS antennas are led to a 90 ° hybrid with coaxial lines using the conductive surface of the roof capacitance 1 as a ground conductor via the antenna conductor 4.

If one uses 1 double-clad, 1mm thick circuit board material (e.g. FR4) for the antenna according to Fig. 4 for the conductive surface of the roof capacitance, all the slots on the top can be etched from the applied copper layer. The two necessary RF lines for GPS are implemented as microstrip lines, with the underside of the board carrying the stripline. Via the antenna conductor 4, the GPS signals are also passed on as microstrip lines and connected to the 90 ° hybrid on the base plate, which is also implemented using stripline technology. This creates an antenna that is easy to set up and reproducible.

FIG. 5 shows a measured vertical section of the directional diagram of the antenna according to FIG. 4 in the upper hemisphere with circular polarization. Because the GPS slot antennas according to FIG. 4 are in a non-symmetrical environment, diagram indentations in the elevation range from 60 ° to 90 ° are currently also obtained for other azimuth angles. The performance of a ceramic patch antenna is also achieved.

The transmission and reception properties of the antenna according to FIG. 4 in the D and E radio service are only slightly influenced by the additional GPS slot antennas.

The total height 20 of the antenna according to FIG. 4 is only about 20 mm and can be built on a circular base plate with a diameter of less than 9 cm.

List of names

• Roof capacity (1)
• conductive base (2)
• Slot (3)
• Antenna conductor (4)
• first edge (5)
• second edge (6)
• Slot length (7)
• Slot width (8)
• first connection point (9a)
• second connection point (9b)
• unbalanced line (10)
• Inner conductor (11)
• Earth conductor (12)
• additional antenna connection point (13)
• first antenna connection point (14)
• Coupling ladder (15)
• Crossover (16)
• 90 degree hybrid circuit (17)
• Contour notches (18)
• Connection point of the first radio service to roof capacity (19)
• Distance of roof capacity 1 to the conductive base level 2 (20)
• Angle (21)
• additional slots (22)
• Frequency band pass (23)
• low noise amplifier (24)
• Distance (25)
• Bandstop (26)
• Bandpass (27)
• Radio (28)

Claims (10)

Antenna for several radio services with the character of a dipole or monopole with an antenna conductor (4) and at least one area-shaped and essentially perpendicular to the antenna conductor (4) oriented roof capacitance (1) for a first radio service with polarization oriented vertically to the roof capacity (1) ,
characterized in that
a roof capacitance is designed in the form of a conductive plate or a thin conductive layer and, in order to design an antenna function for at least one other radio service, at least one slot (3) with polarization oriented parallel to the roof capacitance (1) in the conductive plate or layer is introduced, the slot length (7) for the formation of a resonance in the frequency range of another radio service and the slot width (8) for the formation of a suitable impedance bandwidth are selected appropriately and that for decoupling signals in the further radio service at the edges of the slot at opposite points a first and second connection point (9a, 9b) are formed. Antenna in the form of a monopole over a conductive base (2) according to claim 1,
characterized in that
an asymmetrical electrical line (10) is connected with its inner conductor (11) to the first connection point (9a) and the ground conductor (12) of the asymmetrical line to the second connection point (9b) and the asymmetrical line (10) in parallel without an electrically effective distance to the conductive plate forming the roof capacitance and also parallel to the surface of the vertically oriented antenna conductor (4). (Fig.1a) Antenna according to claim 1 and 2,
characterized in that
the antenna conductor (4) is designed to be area-conductive and is conductively connected to the roof capacitance (1) with a first edge (5) and is conductively connected to the conductive base area (2) with the second edge (6) and the further antenna connection point (13 ) is formed for the further frequency range on the conductive base area (2) and that there is another coupling conductor (15) oriented vertically and connected to the conductive base area (2) and roof capacitance (1) and the first antenna connection point (14) for the first radio service is formed between the conductive base area (2) and the end of the further vertically oriented coupling conductor (15) facing it. (Fig. 1a) Antenna according to claim 1 to 3,
characterized in that
the roof capacitance (1) and the vertically oriented, flat antenna conductor (4) are designed as printed circuit boards with a conductive cover on both sides, and the conductive surface is formed by the conductive material on one side of the circuit boards and the asymmetrical line is designed as a strip line, the strip conductor being printed on the opposite side of the conductive surface and the surface forming the ground conductor of the line. (Fig.2) Antenna according to claim 1 to 4,
characterized in that
the conductive base area is oriented horizontally and the monopole antenna for the frequency band of a terrestrial telephone radio service with vertical polarization is tuned as the first radio service and as a further radio service is tuned to a satellite radio service with essentially horizontally polarized incident waves. Antenna according to claim 1 to 5,
characterized in that
the roof capacity and the vertically oriented antenna conductor (4) are dimensioned such that there is resonance in the first radio service (GSM frequency range) and the slot (3) in The length and width is designed in such a way that its resonance is suitable for receiving further radio service (GPS). Antenna according to claim 1 to 6,
characterized in that
There are two slots, each with two connection points and an unbalanced line connected to it for another radio service with circular polarization, and the two lines lead to the two inputs of a 90-degree hybrid circuit, at the output of which the antenna connection point (13) for further radio service is formed and the slots in the conductive plate of the roof capacitance are oriented at an angle of almost 90 degrees to one another in such a way that the reception of the circularly polarized waves with a predetermined direction of rotation is optimal. (Fig.3a) Antenna according to claim 7,
characterized in that
at the further antenna connection point (13) a frequency band pass (23) for passing the signals for the further radio service and a low-noise amplifier (24) on one of the conductive surfaces of the antenna, but preferably on the conductive base surface (2) of the antenna. (Fig.3b) Antenna according to claim 3 to 8,
characterized in that
In order to design an antenna function for a second first radio service with a higher frequency and with polarization oriented vertically to the conductive base area, slots (22) are introduced into the roof capacitance (1) in a manner known per se. (Fig.4) Antenna according to claims 1 to 8,
characterized in that
the antenna conductor (4) is designed as a three-dimensional body and the asymmetrical line (10) is routed either in the field-free interior of this antenna conductor or electrically ineffectively parallel to the outer surface of this antenna conductor (4) to the conductive base area and on the conductive base area (2) There is a crossover network (16) into which the unbalanced line (10) is inserted and to which the vertically oriented antenna conductor (4) is connected and to which either separate antenna connection points (14, 13) are available for all radio services or a common antenna connection point for all radio services are present. (Fig. 1b)

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