EP2693565A1 - Electrical radiator for vertically polarised radio signals - Google Patents

Abstract

The emitter (1) has polygonal or elliptical/circular closed ring conductor that forms horizontally oriented conductor loop. Three vertical emitters (4a,4b) are electromagnetically coupled to ring conductor at conductor loop coupling points (7a-7c). The vertical emitters are coupled to electrically conductive base area (6) between coupling points and earth terminal point (3a-3c). The vertical emitter is excited via emitter infeed point (5), so that low-resistance resonance provided with character of series resonance is provided at infeed point.

Description

The invention relates to an electric radiator for vertically polarized radio signals for a radio service with a narrow frequency bandwidth around a frequency fo with the free space wavelength λo in the GHZ range for the preferred use on vehicles.

Due to the large number of radio services, the availability of which has become indispensable in the vehicle, in the design of antennas it is particularly important to have a small construction volume in conjunction with the smallest possible height. In many cases it is not possible with good antenna performance and not appropriate to cover a number in each case relatively narrow, but in the frequency relatively widely spaced frequency ranges operating radio services with a broadband antenna. In many cases, the radio signals of the various radio services are also broadcast with different polarization, so that it is not appropriate to meet the various requirements with an antenna. Rather, it is important for vehicle antennas to create antennas with filigree structures for the individual radio services, which can be combined with antennas for other radio services, in particular with the smallest possible height and often with a small footprint, in order to design combination antennas with a small space requirement as a whole , Such combination antennas are optionally covered with a plastic sheath as Radom or even deepened introduced into a molding of the body as a cavity. In addition, the design of vehicle antennas has a high demand on their mechanical stability and vibration resistance. The exemplary consideration of only a few antennas of the radio frequency services required in the decimetre waveguide, such as antennas for the GSM mobile services and the narrow band in the L-band digital broadcasting service at about 1.5 GHz, each with vertical polarization radiated Radio signals and the SDARS narrowband digital satellite broadcasting service at approximately 2.3 GHz, whose signals are broadcast in circular polarization from the satellite, indicate that the creation of a single broadband antenna to cover all radio services would lead to insurmountable difficulties. In addition, for the reception of all the above-mentioned radio services due to the mass-produced antennas, the profitability in the production of crucial importance.

mit Zo = 120π Ohm = Feldwellenwiderstand des freien Raums und der Lichtgeschwindigkeit co.For the mobile service GSM long since vertical emitters are used, as for example in the EP 1 445828 are described. To reduce such emitters, a roofing capacity can be used, as for example in Meinke-Gundlach, Taschenbuch der Hochfrequenztechnik, Springer-Verlag 1986, N16 , Table 1 and in connection there with Figure 6 is described for the elementary radiator. The minimum required height h of such an electrically short monopole radiator, when passing through an inductance 15, as in FIG. 4a , is supplemented with the inductance value Lm, is measured at the frequency bandwidth requirement B for the affected service at its center frequency fo with the free space wavelength λo. This relationship between the relative radiator bandwidth Brel = B / fo, the radiation resistance Rsm and its capacitance Csm is in Archive for Electronics and Transmission (AEÜ) in Volume 30, (1976 No. 9, there in equation 11, and taking into account the known relationship for the radiation resistance, Rsm = 160 * π ² * (hem / λo) ² ohms, of the short monopole radiator with its effective height hem $$\frac{B}{\mathit{fo}}=\left({\mathit{<figure-callout\; id="2"\; label="hem"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">hem</figure-callout>}}^2*\mathit{Cs}\right)*{\mathit{<figure-callout\; id="3"\; label="fo"\; filenames="imgf0002.png,imgf0004.png"\; state="\{\{state\}\}">fo</figure-callout>}}^3*\frac{\mathit{Zo}}{{\mathit{co}}^2}*{\mathrm{<figure-callout\; id="2"\; label="\pi "\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">\pi </figure-callout>}}^2*\frac{\mathrm{<figure-callout\; id="3"\; label="8th"\; filenames="imgf0002.png,imgf0004.png"\; state="\{\{state\}\}">8th</figure-callout>}}{3}=\left({\mathit{hem}}^2*\mathit{Cs}\right)*k=\mathit{BFM}*k$$

with Zo = 120π ohm = field wave resistance of free space and the speed of light co.

The decisive mechanical dimensions of the antenna are included for the considerations made here only in the expression for the bandwidth factor BFm in brackets, with sufficiently large roof capacity Cs, the effective height hem of the monopole radiator is equal to its geometric height h. Thus, for the satisfaction of the relative bandwidth of an electrically short radiator for a particular service with the center frequency fo, the term outside the bracket expression "bandwidth factor" = BFm for the monopole can be a constant independent of its dimensions k are summarized. In the following, this radiator bandwidth represents the reference bandwidth. In the impedance diagram in FIG FIG. 4a the impedance profile of the radiator is shown as a curve in the frequency range around the resonance frequency fo, the impedance at the resonance point representing the radiation resistance Rsm, which, based on a normalized resistance (target impedance) ZL = 50 ohms from the above relationships for this elementary radiator, as follows , let represent: $$\frac{\mathit{rsm}}{\mathit{ZL}}=3.2*{\mathrm{<figure-callout\; id="2"\; label="\pi "\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">\pi </figure-callout>}}^2*{\left(\frac{\mathit{hem}}{\lambda \mathrm{<figure-callout\; id="2"\; label="O"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">O</figure-callout>}}\right)}^2\approx 32*{\left(\frac{H}{\lambda \mathrm{<figure-callout\; id="2"\; label="O"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">O</figure-callout>}}\right)}^2$$

Regarding the use of such a resonant radiator 29 in FIG. 4a below, this ZL-related radiation resistance Rsm is of particular importance for use in vehicles. Due to its extreme offset from the adaptation point ZL = 50 ohms for conventional radio systems in the vehicle, the transformation of this resistor into the matching point ZL in the matching network 35 is complicated in the case of electrically small antennas 36 and reduces the bandwidth of the antenna at the antenna connection point 34, so that the one given above Beam band width B according to equation (1) is no longer available. In addition, matching networks 35, especially when designed from complex circuit structures, make the manufacture of vehicle antennas more expensive. The impedance of a known capacitive emitter with roof capacitance with inductance Lm 15 for example generating a resonance at a frequency of fo of about 1.5 GHz in the frequency band of a radio service in question, as in FIG. 4a , is therefore very unfavorable especially in the mechanical dimensions given there and the electrically small height h / λo of about 1/20. Added to this is the mechanical instability, which is accompanied by the structure of the with the roof capacity at the top mechanically loaded spotlight. With regard to its electrical properties, this radiator is to be used below as a reference radiator 29.

The object of the invention is therefore to provide a radiator according to the preamble of claim 1, which even at very small electrical height h / λo and mechanical stability in the frequency environment of its resonant frequency fo has an impedance in the vicinity of the prescribed and normalized for radio systems in vehicles resistance ZL = 50 ohms, so that the technical complexity to complement the radiator through a matching network for adaptation to ZL = 50 ohms to an antenna over a relatively large frequency bandwidth are made economically can.

This object is achieved in an antenna according to the preamble of the main claim by the characterizing features of the main claim.

According to the invention, the (electrically small) radiator 1 for vertically polarized radio signals for a narrow bandwidth radio service by a frequency f o with the free space wavelength λ o in the GHZ range comprises a substantially horizontally oriented conductor loop arranged above a conductive base surface 6 Radiator feed 5 for electromagnetic excitation of the conductor loop relative to the conductive base 6. The conductor loop is designed by a polygonal or elliptical / circular closed ring conductor 2 n a substantially horizontal plane with the height h smaller λo / 6 over the conductive base 6 extending. Distributed at the circumference of the ring conductor 2 are at least three electromagnetically coupled to conductor loop coupling points 7 and to the conductive base 6 extending towards vertical radiators 4, 4b, 4c, 4d, wherein at least two of the vertical radiator 4b, 4c and optionally 4d are electrically coupled to the electrically conductive base 6 at ground connection points 3b, 3c, 3d and a vertical radiator 4a is excited via the radiator feed 5 at its lower end. The vertical radiator 4b, 4c, 4d, which is coupled to the electrically conductive base area 6 between its conductor loop crosspoints 7a, 7b, 7c, 7d and which are each coupled to a ground terminal 3b, 3c, 3d, and which is excited by the radiator feed point 5, between its Conductor loop coupling point 7a and the radiator feed 5 each have inductively active components 13a, 13b, 13c, 13d, so that at the radiator feed 5 at the frequency fo a low-impedance resonance is given by the character of a series resonance.

With a radiator according to the invention, the additional advantage that the radiator gain in flat radiation even at very low electric radiator height can be made larger by flattening the vertical directional diagram with azimuthal omnidirectional characteristics than with an elementary radiator. Furthermore, the radiator can be made as a filigree yet mechanically stable structure, which allows the combination with another vertically polarized antenna. A particular advantage in this case shows the possibility of an extremely economical way of producing the radiator in large numbers, which is particularly important for use in vehicles of particular importance. Furthermore, the radiator according to the invention can be designed by little complicated complementary measures for an additional wider frequency range as a circularly polarized antenna, in particular for the reception of satellite radio signals. A significant advantage of a radiator according to the invention is further given by the possibility that the remaining free in the center of the loop area on the base can be largely used for attaching additional combined antennas for additional other radio services.

According to an advantageous embodiment, the ring conductor (2) may be formed by a closed wire ring and coupled to the vertical radiators by galvanic connection.

• Fig. 1:
  Strahler 1 nach der Erfindung mit kreisförmigem, zum Beispiel drahtförmigem Ringleiter 2 in der Höhe h über einer leitenden Grundfläche 6 verlaufend, mit N= 3 an Ringleitungs-Koppelpunkten 7a, 7b, 7c an den Ringleiter angeschlossenen vertikalen Strahlern 4a, 4b, 4c, wobei zwei vertikale Strahler 4b, 4c an ihrem unteren Ende über Masse-Anschlusspunkte 3b 3c mit der leitenden Grundfläche 6 verbunden sind und am unteren Ende eines der vertikalen Strahler 4a die Strahlerspeisestelle 5 gebildet ist, über welche der Strahler 1 erregt ist. Alle vertikalen Strahler 4a, 4b, 4c besitzen induktiv wirksame Komponenten 13a, 13b, 13c zur Bewirkung der niederohmigen Resonanz etwa bei der mittleren Frequenz fo des Funkdienstes mit vertikaler Polarisation.
• Fig. 2:
  Strahler nach der Erfindung wie in Figur 1, jedoch mit quadratischem bzw. rechteckigem, zum Beispiel flächig gestaltetem Ringleiter 2 und größerer Leiterbreite 8 und mit N = 4 Ringleitungs-Koppelpunkten 7a, 7b, 7c, 7d zur Ankopplung der vier vertikalen Strahlern 4a, 4b, 4c, 4d, an seinen vier Eckpunkten.
• Fig. 3:
  Strahler nach der Erfindung wie in Figur 2, jedoch mit der Besonderheit, dass die Breite des Ringleiters 2 derart gewählt ist, dass innerhalb der äußeren Berandung des Ringleiters 2 eine geschlossene, leitende Fläche gebildet ist.
• Fig. 4a und Fig. 4b
  Gegenüberstellung der Impedanzverläufe eines Strahlers mit quadratischem Ringleiter 2 nach der Erfindung gemäß Fig. 4b und eines Stabmonopols mit quadratischer Dachkapazität und Fußpunktinduktivität Lm 15 als Referenzstrahler 29 gemäß Fig.4a in der komplexen, auf ZL bezogenen Impedanzebene jeweils in der Frequenznähe der Resonanzfrequenz fo = 1.4 GHz bei gleicher Höhe h = 1cm und gleicher Kantenlänge 23 von 2cm der quadratischen Dachkapazität des Referenzstrahlers 29 und des quadratisch gestalteten Ringleiters 2 mit der Leiterbreite 8 von 2mm des Strahlers 1 nach der Erfindung. Die einander gleichen äußeren Abmessungen der beiden Strahler 1 und 29 bedingen zunächst gleiche relative Strahlerbandbreiten von Brel = 3,6%. Die mit dem extrem niedrigen Resonanzwiderstand Rsm/ZL = 0,06 gemäß Fig. 4a verbundene Schwierigkeit der Anpassung der Strahlerimpedanz an ZL bedingt jedoch einen großen technischen Aufwand und eine Reduzierung der wirksamen relativen Bandbreite des durch ein Anpassnetzwerk 35 ergänzten Strahlers. Das Verdienst der vorliegenden Erfindung ist es, dass diese Nachteile bei einem Strahler nach der Erfindung mit Rs/ZL = 0,85 gemäß Fig. 4b in der Praxis entfallen können.
• Fig. 5:
  Verlauf des auf ZL bezogenen Strahlungswiderstands bei der Resonanzfrequenz fo in Abhängigkeit von der relativen geometrischen Strahlerhöhe h/λo = h' des Referenzstrahlers 29 (strichpunktiert) und des Strahlers 1 nach der Erfindung (N = 4) in Figur 4b. Die Kurven N = 3, N = 4 oder N = 5 beziehen sich auf Strahler 1 nach der Erfindung mit jeweils einem als reguläres Dreieck, reguläres Viereck oder Fünfeck gestalteten Ringleiter 2 mit gleicher relativer Strahlerbandbreite Brel. Der dargestellte Bereich für h' > 0,025 (sh. Marker) kennzeichnet den nutzbaren Wertebereich für h', wenn die Forderung 0,5 < Rs/ZL < 2 (sh. Grenzlinien) beispielhaft erfüllt werden soll.
• Fig. 6:
  Impedanzverläufe von Strahlern nach der Erfindung mit äußeren Abmessungen wie in Figur 4b, jedoch mit einer Leiterbreite 8 von 5 mm in Figur 6a und der Besonderheit in Figur 6b, dass die Breite des Ringleiters 2 derart gewählt ist, dass innerhalb der äußeren Berandung des Ringleiters 2 eine geschlossene Fläche gebildet ist. Ein Vergleich der Impedanzverläufe in den Figuren 6a und 6b zeigt, dass der Widerstand Rs/ZL bei der Resonanzfrequenz fo durch den Gestaltungsunterschied der Strahler nur wenig beeinflusst ist. Ferner zeigt sich, dass sich die relative Bandbreiten Brel = 3,6% der beiden Strahler in den Figuren 6a bzw. 6b im Rahmen der Nachweisbarkeit in der Praxis nicht unterscheiden. Der äußerst geringfügig unterschiedlichen Wirkung der unterschiedlichen Ringleiter 2 ist durch geringfügigen Nachabgleich der Induktivitäten 15a, 15b, 15c, 15d Rechnung getragen.
• Fig. 7: zeigt das vertikale Richtdiagramm in dB-Eichung eines Strahlers nach der Erfindung mit einer gegenüber einem elektrisch kleinen Elementarstrahler (4,77dBi) erhöhten Richtwirkung von 5,57dBi bzw. 5,31dBi durch die voneinander beabstandeten vertikalen Strahler 4a-d.
• Fig. 8:
  Azimutales Richtdiagramm für Flachstrahlung des in Figur 7 besprochenen Strahlers mit nur geringfügiger Abweichung vom Runddiagramm mit Schwankungen zwischen 5,57dBi und 5,31dBi. Fig. 9:
• Beispielhafte Realisierung eines Strahles nach der Erfindung mit rechteckförmigem Ringleiter 2 mit äußerer Querabmessung 16 und äußerer Längsabmessung 17 und
  Gestaltung der vertikalen Strahler in der Weise, dass die für Resonanz notwendigen induktiv wirksamen Komponenten 13a -13d in den einzelnen Strahlern jeweils durch Formung vertikaler Strahlerteile 20 und horizontaler Strahlerteiler 21 gegeben sind. Durch Wahl entsprechender Abmessungen kann an der Strahlerspeisestelle 5 Anpassung an ZL ohne weitere Anpassungselemente erzielt werden, sodass durch die Strahlerspeisestelle 5 die Antennenanschlussstelle 24 gegeben ist.
• Fig. 10:
  Beispiel wie in Figur 9, jedoch mit schräg verlaufenden Strahlerteilen 22 der vertikalen Strahler 4a, 4b, 4c, 4d.
• Fig. 11:
  Strahler nach der Erfindung in einer ausreichenden Kavitätstiefe 12, welche durch Ausformung der leitenden Grundfläche 6 gestaltet ist, so dass der Strahler zum Beispiel ohne Erhebung über die Karosseriefläche in die Fahrzeugkarosserie integriert ist. Die Basisfläche 39 der Kavität 38 ist im Beispiel als gedruckte Leiterplatte gestaltet und die induktiv wirksamen Komponenten 13a -13d sind als gedruckte Induktivitäten 32a, 32b, 32c, 32d realisiert.
• Fig. 12:
  vergleichende Darstellung der auf ZL bezogenen Impedanzverläufe eines Strahlers mit kreisförmiger Ringleitung und vier vertikalen Strahlern nach der Erfindung in Kurve a) und eines Monopols mit Dachkapazität als Referenzstrahler 29 in Kurve b), jeweils im Frequenzbereich zwischen 100 MHz und 2 GHz und gleichen Resonanzfrequenzen fo = 1,54 GHz. Der unterschiedliche Charakter der beiden Strahler ist in ihrem Verhalten bei niedrigen Frequenzen begründet, wobei die Impedanz in Kurve a) dort induktiv ist und deren Realteil mit f⁴ wächst und die Impedanz in Kurve b) dort kapazitiv ist und deren Realteil langsamer, d.h. mit f², ansteigt.
• Fig. 13:
  Nachweis der vorteilhaften Frequenzselektivität der Antenne nach der Erfindung gemäß dem Impedanzverlauf a) in Figur 12 anhand des Frequenzverlaufs des VSWR, bezogen auf den Widerstand ZL nach Kurve a) in Figur 12 mit sehr niedrigen Werten im Frequenzbereich mit der Nutzbandbreite B um die Resonanzfrequenz fo und extrem günstigen hohen Werten des VSWR bei von fo weit abweichenden Frequenzen. Im Gegensatz hierzu sind die Werte des VSWR gemäß dem Impedanzverlauf b) in Figur 12 des Referenzstrahlers 29 im Nutzbereich um fo ungünstig groß und bei weitab liegenden Frequenzen ungünstig klein.
• Fig. 14:
  Beispiel eines Strahlers nach der Erfindung in Kombination mit einer Antenne für den Empfang zirkular polarisierter Satelliten-Funksignale auf einer höheren Frequenz fs als für den Funkdienst mit vertikaler Polarisation. Im Beispiel ist am unteren Ende der vertikalen Strahler 4 jeweils anstelle der gedruckten Induktivität 32a, 32b, 32c, 32d in Figur 11 ein frequenzselektiver Zweipol gestaltet, welcher beispielhaft jeweils aus der Parallelschaltung eines kapazitiv wirkenden Elements 26 und einer Induktivität 15a, 15b, 15c, 15d besteht, so dass bei der niedrigeren Frequenz die gewünschte induktive Wirkung und bei der höheren Frequenz fs die gewünschte kapazitive Wirkung der Blindelement-Schaltung 27a-d gegeben ist. Der Ringleiter 2 bildet bei der höheren Frequenz fs eine durch die kapazitive Wirkung der Blindelement-Schaltung 27 bedingte, in Resonanz befindliche Ringleitung mit Ausbildung einer umlaufenden Welle auf dieser Leitung, sodass zirkulare Polarisation bei dieser Frequenz fs gegeben ist.
• Fig. 15:
  a) zeigt die vorteilhafte Kombination eines Strahlers mit nicht zu breitem Ringleiter 2 nach der Erfindung mit einem im Wesentlichen stabförmigen Strahler 28 im Zentrum Z des Ringleiters 2 für einen weiteren Funkdienst bzw. mehrere weitere Funkdienste mit vertikaler Polarisation auf anderen Frequenzen als fo. Zur Vermeidung von Strahlungskopplung zwischen den beiden Strahlern ist der stabförmige Strahler 28 in Leiterstücke 24 unterteilt, deren elektrische Länge nicht größer ist als 3/8*λo. b) die Unterbrechungsstellen sind durch frequenzselektive Zweipole 25 überbrückt, welche bei der Frequenz fo hochohmig und in den Frequenzbereichen der anderen Funkdienste niederohmig sind.

The invention will be explained in more detail below with reference to exemplary embodiments. The accompanying figures show in detail:

• Fig. 1 :
  Emitter 1 according to the invention with a circular, for example, wire-shaped ring conductor 2 in height h over a conductive base 6 extending, with N = 3 at ring line crosspoints 7a, 7b, 7c connected to the ring conductor vertical radiators 4a, 4b, 4c, wherein two vertical radiators 4b, 4c are connected at their lower end via ground connection points 3b 3c to the conductive base 6 and at the lower end of one of the vertical radiators 4a, the radiator feed 5 is formed, via which the radiator 1 is energized. All the vertical radiators 4a, 4b, 4c have inductively effective components 13a, 13b, 13c for effecting the low-resistance resonance at approximately the center frequency fo of the vertical polarization service.
• Fig. 2 :
  Emitter according to the invention as in FIG. 1 However, with square or rectangular, for example, surface designed ring conductor 2 and 8 larger conductor width and with N = 4 loop coupling points 7a, 7b, 7c, 7d for coupling the four vertical radiators 4a, 4b, 4c, 4d, at its four vertices.
• Fig. 3 :
  Emitter according to the invention as in FIG. 2 , However, with the special feature that the width of the ring conductor 2 is selected such that within the outer boundary of the ring conductor 2, a closed, conductive surface is formed.
• Fig. 4a and Fig. 4b
  Comparison of the impedance curves of a radiator with square ring conductor 2 according to the invention according to Fig. 4b and a rod monopole with square roof capacitance and base point inductance Lm 15 as the reference radiator 29 according to FIG 4a in the complex, on ZL-related impedance level in each case near the frequency of the resonant frequency fo = 1.4 GHz at the same height h = 1cm and the same edge length 23 of 2cm of the square roof capacity of the reference radiator 29 and the square shaped ring conductor 2 with the conductor width 8 of 2mm of the radiator 1 according to the invention. The same outer dimensions of the two radiators 1 and 29 initially cause the same relative radiator belt widths of Brel = 3.6%. Those with the extremely low resonance resistance Rsm / ZL = 0.06 according to Fig. 4a However, the associated difficulty of matching the emitter impedance to ZL requires a great deal of technical effort and a reduction in the effective relative bandwidth of the emitter complemented by a matching network 35. The merit of the present invention is that these disadvantages in a radiator according to the invention with Rs / ZL = 0.85 according to Fig. 4b can be omitted in practice.
• Fig. 5 :
  Course of the relative to ZL radiation resistance at the resonant frequency fo as a function of the relative geometric radiator height h / λo = h 'of the reference radiator 29 (dash-dotted lines) and the radiator 1 according to the invention (N = 4) in FIG. 4b , The curves N = 3, N = 4 or N = 5 refer to radiator 1 after the Invention with one designed as a regular triangle, regular square or pentagon ring conductor 2 with the same relative radiator band width Brel. The range shown for h '> 0.025 (see marker) identifies the usable value range for h' if the requirement 0.5 <Rs / ZL <2 (see borderlines) is to be met by way of example.
• Fig. 6 :
  Impedance curves of radiators according to the invention with external dimensions as in FIG. 4b , but with a conductor width 8 of 5 mm in FIG. 6a and the peculiarity in FIG. 6b in that the width of the ring conductor 2 is chosen such that a closed surface is formed within the outer boundary of the ring conductor 2. A comparison of the impedance curves in the FIGS. 6a and 6b shows that the resistance Rs / ZL at the resonant frequency fo is only slightly affected by the design difference of the radiators. Furthermore, it can be seen that the relative bandwidths Brel = 3.6% of the two radiators in the FIGS. 6a or 6b in the context of verifiability in practice. The extremely slight difference in the effect of the different ring conductors 2 is taken into account by slight rebalancing of the inductances 15a, 15b, 15c, 15d.
• Fig. 7 Figure 12 shows the vertical directional diagram in dB calibration of a radiator according to the invention with a 5.57dBi and 5.31dBi directivity, respectively, enhanced by a 5.7dBi and 5.31dBi versus a small electric elementary radiator (4.77dBi) by the spaced-apart vertical radiators 4a-d.
• Fig. 8 :
  Azimuthal directional diagram for flat radiation of in FIG. 7 discussed spotlight with only slight deviation from the circular diagram with variations between 5.57dBi and 5.31 dBi. Fig. 9 :
• Exemplary realization of a beam according to the invention with rectangular ring conductor 2 with outer transverse dimension 16 and outer longitudinal dimension 17 and
  Design of the vertical radiator in such a way that the necessary for resonance inductively effective components 13a -13d in the individual radiators respectively Forming vertical radiator parts 20 and horizontal beam splitter 21 are given. By choosing the appropriate dimensions, adaptation to ZL can be achieved at the radiator feed point 5 without further adaptation elements, so that the antenna connection point 24 is provided by the radiator feed point 5.
• Fig. 10 :
  Example as in FIG. 9 but with oblique beam parts 22 of the vertical radiators 4a, 4b, 4c, 4d.
• Fig. 11 :
  Emitter according to the invention in a sufficient cavity depth 12, which is designed by shaping the conductive base 6, so that the radiator is integrated, for example, without elevation over the body surface in the vehicle body. The base surface 39 of the cavity 38 is designed in the example as a printed circuit board and the inductively active components 13a -13d are realized as printed inductors 32a, 32b, 32c, 32d.
• Fig. 12 :
  Comparative representation of the ZL related impedance curves of a radiator with circular loop and four vertical radiators according to the invention in curve a) and a monopole with roof capacity as a reference radiator 29 in curve b), respectively in the frequency range between 100 MHz and 2 GHz and the same resonant frequencies fo = 1.54 GHz. The different character of the two emitters is due to their behavior at low frequencies, the impedance in curve a) is there inductive and their real part with f ⁴ grows and the impedance in curve b) is capacitive there and the real part slower, ie with f ² , increases.
• Fig. 13 :
  Detection of the advantageous frequency selectivity of the antenna according to the invention in accordance with the impedance curve a) in FIG FIG. 12 based on the frequency curve of the VSWR, based on the resistance ZL according to curve a) in FIG. 12 with very low values in the frequency domain with the useful bandwidth B around the resonant frequency fo and extremely favorable high values of the VSWR at frequencies which differ far from fo. In contrast, the values of the VSWR are according to the Impedance curve b) in FIG. 12 of the reference radiator 29 in the useful range to fo unfavorably large and unfavorably small at far frequencies.
• Fig. 14 :
  Example of a radiator according to the invention in combination with an antenna for receiving circularly polarized satellite radio signals at a higher frequency fs than for the vertical polarization service. In the example, at the lower end of the vertical radiator 4 respectively in place of the printed inductance 32a, 32b, 32c, 32d in FIG. 11 a frequency-selective dipole designed, for example, each of the parallel circuit of a capacitive element 26 and an inductance 15a, 15b, 15c, 15d, so that at the lower frequency, the desired inductive effect and at the higher frequency fs the desired capacitive effect of the dummy element Circuit 27a-d is given. The ring conductor 2 forms at the higher frequency fs due to the capacitive effect of the dummy element circuit 27, resonant ring line with the formation of a rotating wave on this line, so that circular polarization is given at this frequency fs.
• Fig. 15 :
  a) shows the advantageous combination of a radiator with not too wide ring conductor 2 according to the invention with a substantially rod-shaped radiator 28 in the center Z of the ring conductor 2 for another service or several other radio services with vertical polarization at frequencies other than fo. To avoid radiation coupling between the two radiators, the rod-shaped radiator 28 is divided into conductor pieces 24 whose electrical length is not greater than 3/8 * λo. b) the interruption points are bridged by frequency-selective two-pole 25, which are high-impedance at the frequency fo and low in the frequency ranges of the other radio services.

The description of the operation of a radiator according to the invention can be graphically based on a comparison with the already mentioned above as a reference radiator 29 monopole rod radiator in Fig. 4a with roofing capacity 11 and an inductance Lm, 15 at the base point according to the prior art. His Fußpunktsimpedanz at the radiator feed 5 is at capacitive capacitive and, given the choice of a suitable inductance Lm 15 at the frequency fo of a radio service considered here, can assume a low-resistance resonance of the character of a series resonant circuit with the resonance impedance Rsm / ZL = 0.06 which is very low in relation to ZL = 50 ohms. This known impedance characteristic is shown by way of example in the frequency environment of the resonance fo = 1.5 GHz for the illustrated radiator with the specified dimensions and the resonance resistor Rsm / ZL = 0.06 which is extremely unfavorable for an impedance transformation in the resistor ZL.

In contrast to the reference radiator 29 in FIG. 4a consists of the radiator according to the invention in the FIGS. 1 and 4b from a ring conductor 2, on whose circumference at least three vertical radiators 4a, 4b, 4c and 4d are arranged, wherein the ring line 2 is excited via one of the vertical radiators 4a and the other vertical radiators 4b, 4c and 4d respectively via an inductance 15 are electrically conductively connected to the conductive base 6. In a particularly preferred embodiment of an antenna according to the invention, the vertical radiators 4a-c and d azimuthally distributed approximately the same and the inductance 15 of all radiators are chosen approximately equal. Depending on the dimensions of the ring conductor 2 and its height h above the base surface 6 results with a suitable choice of inductors 15 according to the invention at the radiator feed 5 in the frequency environment of the desired resonant frequency fo the impedance characteristic of a low-resistance series resonance, as shown in the FIGS. 4b . 6a . 6b and in FIG. 12 , Curve a) is shown. Upon excitation of a radiator according to the invention at the radiator feed 5 at frequencies far below the resonant frequency fo, the measurable impedance there is the same character as that of an electrically small loop antenna whose radiation resistance increases with f ⁴ and the reactance proportional to the frequency f. It is for example in FIG. 1 by the ingenuity of the current in the fed radiator 4a to the two streams in the other vertical radiators 4b and 4c easily understand that largely cancel the vertically polarized radiation contributions in the vertical radiators. Only in the frequency neighborhood of the resonant frequency fo are the currents in all vertical radiators in the same direction, so that the vertically polarized radiation contributions add together in a completely supportive manner. According to the invention results in the crucial phenomenon that the real part the impedance at the radiator feed 5 is about the square of the number N of the vertical radiator greater than a reference radiator 29 of the same geometric height h according to equation (2), so that at electrically low height h / λo and with a suitable choice of the number N of the vertical Emitter 4, the emitter impedance can be designed much closer to the target impedance ZL for impedance matching. According to the invention, in approximation for the resonance resistance of the radiator at the frequency fo: $$\frac{\mathit{Rs}}{\mathit{ZL}}=\frac{\mathit{rsm}}{\mathit{ZL}}*{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">N</figure-callout>}}^2\approx 32*{\left(\frac{H}{\lambda \mathrm{<figure-callout\; id="2"\; label="O"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">O</figure-callout>}}\right)}^2*{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">N</figure-callout>}}^2$$

Here, as a particular advantage of a radiator according to the invention that the bandwidth of its impedance curve is not smaller than that of a reference radiator 29 with the same outer dimensions of the roof capacitance 11 and the ring conductor 2 in the FIGS. 4a or 4b and at the same heights h / λo, so that approximately the same bandwidth factor BF = BFm according to equation (1) applies to the two radiators. A comparison of the bandwidths of the impedance curves in the FIGS. 4b for the radiator according to the invention with the inductors 15 of about 25nH each and in FIG. 4a for the reference radiator 29, within the detectable accuracy, the same values for the relative bandwidth of Brel = 3.6% are obtained. This is determined in each case by the frequency spacings of the impedances with + 45 ° and -45 ° phase around the resonance frequency fo -1.5 GHz.

However, as already explained above, an antenna based on the reference radiator 29 with a matching network 35 for transforming the radiator impedance into the target impedance ZL undergoes a bandwidth reduction, which is not subject to a radiator according to the invention due to its favorable radiator impedance. In addition, results in a radiator according to the invention, the additional advantage that the bandwidth factor is practically independent of the conductor width 8 in FIG. 2 , If the vertical radiators 4a-d according to the invention are attached approximately to the outer boundary of the ring line 2, then the currents on the outer boundary of the ring line contribute to the formation of the radiator properties, so that the bandwidth factor of the conductor width 8 is virtually independent to the special case that the ring conductor by a closed area, as in FIG. 6b , is formed. The impedances of the radiators according to the invention in the FIGS. 4b . 6a and 6b show in comparison with increasing ring conductor width 8 only insignificantly changing resonance resistance Rs at the frequency fo. Thus, the bandwidth of the radiator according to the invention is mainly dependent on the relative radiator height, ie with (h / λo) ² and the capacitance of the ring conductor 2 according to its outer boundary. However, it is practically independent of the ring conductor width 8 and the diameter d of a mechanically intrinsically stable wire-shaped ring conductor 2, as can be seen from a comparison of the in the FIGS. 6a and 6b specified bandwidths. This results in the significant advantage in designing an antenna for vehicles that the space in the center Z of the radiator can be provided for combination with other radiators for other radio services.

Particularly for the design of combination antennas for a number of radio services in a confined space on vehicles, the frequency selectivity of a radiator 1 according to the invention is of particular advantage. This can be clearly seen from the comparison of the frequency response of the VSWR values of a radiator 1 according to the invention with resonant frequency fo = 1.53 gigahertz FIG. 13 , Curve a), and a reference radiator 29 with the same external dimensions in curve b). In the frequency neighborhood of the resonance frequency, the inventive advantage of the effortless adaptation of the impedance of the radiator according to the invention to ZL = 50 ohms with respect to the reference radiator 29 with a VSWR value of more than 20 dB. On the other hand, the VSWR values of the reference radiator 29 are far greater than the resonance frequency on average by about 20 dB, so that a radiator according to the invention is much more decoupled from adjacent antennas for other radio services, such as telephone services with strong transmission radiation.

As already mentioned above FIG. 5 described there is the relationship between the resonance resistance at the frequency fo on the relative geometric height h / λo = h 'of the radiator in FIG. 4b applied for N = 4. In comparison with the curves for N = 3 and N = 5, it can be seen that, with a suitable choice of the number N of vertical radiators on a ring conductor 2 designed as an N-corner, the resonance resistance is within a large value range of h ', which is of interest for practical use. = h / λo near the Target resistance ZL can be designed. The dot-dash curve for the impedance of the monopole with roofing capacity as a reference radiator 29 with the same external dimensions shows the comparison of more than an order of magnitude deviating low values.

In FIG. 7 the vertical radiation pattern of a radiator according to the invention is shown with an advantageously increased gain over a prior art antenna according to the prior art and FIG. 8 shows the azimuthal circular diagram with the azimuthal fluctuation Gmax-Gmin ~ 0.26 dB. The gain increase in the frequency environment of the resonant frequency f o is due to the spacing of the vertical radiators 4a-4c and their action as a radiator group with co-excited currents, but on the other hand causes only the above-mentioned slight azimuthal gain fluctuation at not too great a distance.

Although the requirement for a small geometric antenna height h represents one of the main tasks for the design of a vehicle antenna and in particular for antennas which in the frequency range around 1.5 GHz, such as for the DAB broadcast service in the L-frequency band, an antenna height of h = 1 cm, that is, h / λo = 1/20, is required, the expansion of the loop 2 is not limited to similarly small values. The advantage associated with the radiator according to the invention is that the transverse extent of the ring conductor 2, which is related to the wavelength λo, is not limited to similarly small values, as is the case for its height h. This makes it possible to increase the bandwidth of the radiator at the same relative radiator height h / λo, or alternatively to reduce the height further with the same bandwidth. By way of illustration, the example of a radiator according to the invention with a circular loop 2 as in FIG. 1 , but with four azimuthally equally distributed vertical radiators 4a-4c and the same height h = 1 cm serve, which at a relative diameter of D / λo = 0.32 at the frequency around 1.5 GHz, the relative bandwidth Brel = B / fo ~ 9% owns. In comparison, the in the FIGS. 4b . 6a and 6b given relative bandwidths Brel~3,6% about the ratio between the length of the square boundary of the ring line 2 to the circumference of the circular loop smaller. The capacity of the ring conductor 2 is thus given approximately by the extended length of its outer boundary and contributes linearly to the formation of the bandwidth B of the impedance around the resonance frequency fo.

Advantageously, the azimuthal radiation pattern is given even with comparatively large transverse expansions of the ring conductor 2 as a circular diagram. In the above example of a circular ring antenna and the relative diameter of D / λ o = 0.32, the stretched length of a ring conductor section between two adjacent ring line crosspoints 7a-7b etc. is one-quarter wavelength = λ o / 4th Although the distance between two opposed vertical radiators is D / λ o = 0.32 and is thus no longer small compared to the wavelength λ o, the azimuthal fluctuation of the radiator gain is less than 0.3 dBi.

In the following, some advantageous forms for the realization of radiators are carried out according to the invention.

In a simple and economical design of a ring conductor 2 with the vertical radiators 4, the ring conductor 2 is designed as a closed approximately wire-shaped ring, with which the vertical radiator 4 are galvanically connected. This ring conductor 2 with radiators 4 can be economically punched from sheet metal and produced by subsequent bending of the radiator 4. Advantageously, the conductive base in the region of the radiator 1 is designed as a printed circuit board. In this, the inductors 15, for example, as spiral-shaped conductor tracks, as in FIG. 11 indicated, printed introduced, wherein at one end of one of the inductors 15 a connection pad is printed as a radiator junction. The prefabricated radiator part can be easily connected to the lower ends of the vertical radiators with the inductors 15 - for example by soldering - whereby a mechanically extremely stable radiator construction is given. This mechanical stability is of great advantage, in particular with regard to the narrow relative bandwidth of some radio services, which counteracts detuning due to mechanical vibrations and ensures high reproducibility in the production process.

In such a radiator with galvanically coupled vertical radiators 4, the ring conductor 2 in the horizontal plane surface and its outer boundary in Be designed substantially symmetrically to its center Z, wherein the inner boundary of the ring conductor 2 inner is designed in such a way that along the circumference of the ring conductor width B is smaller than 1/4 of the measured over the center Z horizontal extension of the ring conductor. As a result, the space around the center Z of the ring conductor 2 is advantageously available for the exemplary design of further antennas.

As already stated above, the similarity of the currents in the vertical radiators 4 is important for the resulting optimal support of the vertically polarized radiation. This is particularly advantageous to achieve when the ring conductor 2 is circular or designed as a regular polygon with N corners and over the circumference L of the circle or at the corners of the N-corner over the circumference of the length L of the ring conductor 2 in number N mutually identical vertical radiators 4a-d in the same length elongated lengths L / N of the structure away from each other via the conductor loop coupling points 7a-d to the ring conductor 2 are galvanically coupled 6. In this case, according to the invention, the resonance at the frequency fo is brought about by designing the inductively active components 13a-d of the vertical radiators 4a-d. To produce the resonance of the ring line radiator 1, the vertical radiators 4a-d can likewise be connected in each case at an interruption point with an inductance 15a-d of the inductive components 13a-d necessary for this purpose.

In a particularly advantageous implementation of the invention, the components 13a-d inductively active in the vertical radiators 4b-d have approximately the same size in all vertical radiators 4a-d, so that-as already stated above-at resonance in these radiators 4a-d flow equal direction currents of about the same size. However, this condition is not necessarily met meticulously for a basic perception of the advantages achieved by the invention in terms of a favorable radiator impedance. By maintaining the equality of the currents, however, optimum conditions can be achieved with regard to the radiator impedance and the azimuthal directional independence of the directional diagram.

The choice of an interruption point for switching on concentrated inductive components is carried out for the production of the radiator 1 particularly low at the lower end of a rod-shaped vertical radiator 4a-d. There can each a concentrated inductance 32 a-32 c between the lower end of the rod-shaped vertical radiator 4 a - d and the conductive base 6 and the terminal located there of the radiator feed 5 are connected. The other terminal of the radiator feed 5 is formed on the conductive base 6. As already indicated above, the inductors 15a-d can advantageously be designed as printed inductances 32a-d on the electrically conductive base 6 designed as an electrically conductive printed circuit board, each at one end with the vertical radiator 4a-d and at the other End are connected to the electrically conductive base 6 and also designed on the coated circuit board a connection of the radiator feed 5.

In a further advantageous embodiment of the invention, the inductors 32a-d can be omitted if the inductively active components 13a-13d are each realized by shaping the vertical radiators 20. For this purpose, vertical radiator parts 20 and horizontally extending radiator parts 21 are formed, so that the in FIG. 1 shown necessary inductive components 13a - 13c are achieved even at a small height h. Here, the design of the vertical radiator parts 20 and the horizontally extending radiator parts 21 in FIG. 9 also combined by oblique radiator parts 22, as in FIG. 10 represented, or carried by meandering radiator parts. A radiator 1 with such vertical radiators 4a-c can be produced, for example, economically from a piece punched from sheet metal and subsequent bending, and the vertical radiators are connected at their lower end to the conductive base 6 or to the radiator junction 5 formed there. A particularly economical solution for use in vehicles is to be achieved by choosing the appropriate dimensions of the radiator 1 in such a way that at the radiator feed 5 adaptation to ZL without matching network 35 is given and the radiator feed 5 -. In accordance with the general illustration in FIG. 4a bottom left - the antenna connection point 34 forms an antenna 36 adapted to ZL.

If the resonant resistance Rs is too low, the impedance matching to ZL can be effected simply by selecting the resonant frequency fo in such a way that the slight detuning of the resonance of the radiator between the radiator feed point 5 occurs at a slightly higher frequency f in the frequency band of the radio service and the adjacent ground terminal 3a occurring impedance is inductive. By parallel connection of a capacitance between radiator feed point 5 and the adjacent ground connection point 3a, impedance matching to ZL can be achieved in a simple manner, whereby the radiator feed point 5 likewise forms the antenna connection point 34 of an antenna 36 adapted to ZL.

In an advantageously easy to manufacture basic shape of a radiator 1 according to the invention, the ring conductor 2 is designed as a square, at the corners of each a ring line crosspoint 7 with a galvanically connected there vertical radiator 4, 4a-d is formed. Three of the radiators 4, 4b-d are connected to the electrically conductive base 6 for coupling to a ground terminal 3b-d via an inductor 13b-d to the ground terminal 3b-d and a radiator 4, 4a, optionally over an inductor 13a connected to the radiator feed 5.

For a radiator - for example, for the above-mentioned radio service DAB in the L-frequency band at a center frequency of f~1.5 GHz - in an advantageous embodiment of the invention, the resonance frequency fo is approximately equal to the center frequency f of the service and the pages of The squares are approximately equal to λo / 10 and the heights h, 9 are approximately equal to λo / 20. A radiator with these external dimensions can advantageously be designed in such a way that there is impedance matching at ZL at the radiator feed point 5 and thus the antenna connection point 34 is provided by the latter.

On the smoothness of the surface of a vehicle body are made primarily for aesthetic reasons, but also for reasons of wind noise high demands. For this purpose, a radiator according to the invention advantageously offers the possibility of sunk the radiator and to integrate without significant loss of its radiation properties in the vehicle body. For this purpose, as in FIG. 11 illustrated, the substantially extending in a base plane E1 conductive base surface 6 at the location of the ring conductor 2 as an upwardly open conductive cavity 38, the conductive cavity base surface 6a in the cavity depth 12 parallel to and below the base plane E1 located base plane E2. In this cavity, the ring conductor 2 in a further horizontal loop level E in height h, 9 extending over the cavity base surface 6a introduced in such a manner that the conductive cavity base surface 6a, the projection surface of the ring conductor 2 at the lying below the conductive surface plane E1 base surface plane E2 at least covers and the cavity side surfaces 40 at each point a contour in have the way that a sufficiently large cavity spacing 10 between the ring conductor 2 and the cavity 38 is given at each point. Naturally, a sinking of the radiation resistance Rs is associated with the recessed installation of a radiator. In particular, in this context too, the increase of the radiation resistance by a factor N ² according to the invention relative to a reference radiator 29 is of particular importance.

In a further advantageous embodiment of the invention, the emitter 1, which is designed for vertical polarization for a radio service to the frequency fo, extended in its function for the reception of circularly polarized satellite radio signals of a satellite service at a frequency fs> fo, as exemplified in Fig. 14 is shown. In contrast to the function for the vertical polarization with in-phase and co-current flows in the vertical radiators 4a-c, the phases of the currents in these radiators are adjusted in such a way that the ring conductor 2 is operated together with the conductive base 6 as a loop, so that at the frequency fs a resonant structure is formed in such a way that is adjusted by feeding via one of the vertical radiator 4d with radiator feed 5 on the loop the current distribution of a current line wave in a single direction of rotation, the phase difference over an azimuthal cycle is just 2π , The supply of the radiator for the function of the circular polarization can also be done at the radiator feed point 5 in an advantageous manner. A radiator for the reception of circularly polarized satellite signals is known from DE 10 2009 040 910 There, for example, in Fig. 17, wherein the feed is given to a vertical radiator via a capacitance and the connection of the other radiator to the electrically conductive base surface 6 also over capacity. For combining the two functions in a radiator according to the present invention, as in Fig. 14a , Is the inductors 15a-d of the coupled to the conductive ground plane vertical radiator 4a-c and the one vertical radiator 4d with radiator feed 5 each have a capacitive element 26a-d connected in parallel. Thus, as in Fig. 14b represented, in each case a dummy element circuit 27a-d given, which for the service at the frequency f continue to have the required inductive effect and at the frequency fs for the satellite service the capacitive effect determining the resonance and the direction of rotation of the rotating shaft.

In a further advantageous embodiment of the invention, the space which can be designed in the center of the ring conductor 2 is used for attaching a further vertically polarized antenna, as shown by way of example in FIG 15A is shown with a rod-shaped antenna 28. For this purpose, a vertical substantially rod-shaped antenna for at least one further radio service can advantageously be designed along a vertical center line VZ. To suppress the radiation coupling between the radiator 1 according to the invention and the other vertically polarized rod-shaped antenna 28 whose conductor is subdivided in such a way by interruption points 14 into separate conductor pieces 24, that the extended lengths 19 of the conductor pieces 24 is not greater than 3/8 the wavelength λo are chosen and the interruption points 14 by frequency-selective dipole 25, as in Fig. 15b shown, bridged. The frequency-selective dipoles 25 are low impedance in the frequency ranges of the other radio services and in the frequency range which is associated with the radiator 1 with ring conductor 2, high-impedance perform. The design of rod-shaped, radiation-isolated antennas bridged by frequency-selectively bridged interruption points is known from the DE103 04 911 ,

Finally, it may be necessary for reasons of increased mechanical stability requirements, for example, to perform the ring conductor 2 as stable as possible. In this case, the ring conductor 2 can essentially be defined by the boundary of a closed conductive surface, as in FIG Fig. 3 , the ring line coupling points 7a, 7b, 7c, 7d are each formed in the vicinity of this boundary. The electrical properties, such. As the radiation resistance Rs at the resonant frequency fo, are only insignificantly influenced by the representation of the ring conductor 2 as a closed surface due to the essential for the function currents along the boundary of the surface. This also applies to the relative radiator bandwidth Brel.

Starting from the bandwidth of an electrically small radiator, the bandwidth B can theoretically by a factor of 2π / In2 be increased by additions to a matching network at the antenna connection point 34 assuming an arbitrarily complicated, but lossless matching network, as cited in the cited document in the AEÜ is. However, the magnification factors that can be achieved in practice are all the smaller, with reasonable economic outlay, the further the radiator impedance deviates from the target impedance ZL. Naturally, losses increase the bandwidth, but to the same extent reduce the radiation gain of an antenna. Thus, the radiator 1 according to the invention is always superior to the reference radiator 29 with matching network even when supplementing with a matching network and taking into account losses in terms of radiation gain and achievable bandwidth.

List of terms

• Spotlight 1
• Ring conductor 2
• Ground connection point 3a, 3b 3c, 3d
• vertical radiators 4, 4a, 4b, 4c, 4d, 4e
• Spotlight 5
• Conductive base 6, 6a, 6b
• Ring line coupling points 7,7a, 7b, 7c, 7d
• Conductor width 8
• Distance of height h, 9
• Cavity distance 10
• Roof capacity 11
• Cavity depth 12
• inductively effective components 13, 13a -13g
• Unterbrechungsstelle14
• Inductance 15, 15a, 15b, 15c, 15d
• Outer transverse dimension 16
• External longitudinal dimension 17
• inner transverse dimension 18
• stretched length 19
• vertical radiator part 20
• horizontal radiator part 21
• obliquely extending radiator part 22
• Edge length 23
• Conductor pieces 24
• Frequency selective dipole 25
• capacitive element 26
• Blind element circuit 27
• rod-shaped radiator 28th
• Reference emitter 29
• Microstrip conductors 30, 30a, 30b, 30c
• Power divider and phase shifter network 31
• Printed inductance 32a, 32b, 32c, 32d,
• Printed circuit board 33
• Antenna connection point 34
• Matching network 35
• Antenna 36
• Distance 37
• Cavity 38
• Cavity base surface 39
• Cavity side surfaces 40
• Cavity distance 41
• Bandwidth B
• Relative bandwidth Brel
• Resonant frequency fo
• Field Wave Resistance of Free Space Zo
• Effective height of the electrically short monopole emitter hem
• Capacity of the electrically short monopole emitter
• Speed of light co
• Free space wavelength λo
• Geometric height h
• Wire diameter d
• Circle diameter D
• Antenna factor of the electrically short monopole radiator BFm
• Antenna factor of the radiator according to the invention BF
• Constant k
• Base plane E1
• Base plane E2
• Ring line level E3
• Number of crosspoints N
• normalized resistance (target impedance) ZL
• Radiation resistance at the resonant frequency Rs
• Reactance X
• Elongated length of the ring line radiator L
• vertical center line VZ

Claims (15)

An electric radiator (1) for vertically polarized radio signals for a narrow frequency bandwidth service by a frequency f o with the free space wavelength λ o in the GHZ frequency range, comprising at least one substantially horizontally oriented conductor loop arranged above a conductive base (6) Radiator feed point (5) for electromagnetic excitation of the conductor loop relative to the conductive base (6),
characterized in that - The conductor loop is designed by a polygonal or elliptical / circular closed ring conductor (2) extending in a substantially horizontal plane with the height h smaller λo / 6 on the conductive base (6), - At the circumference of the ring conductor (2) approximately equally distributed at least three conductor loop coupling points (7) with the ring conductor (2) electromagnetically coupled and the conductive base (6) extending vertical radiator (4, 4a-d) are present, at least two of the vertical radiators (4, 4a-d) are electromagnetically coupled to the electrically conductive base (6) at ground connection points (3b-d) and a vertical radiator (4a) is excited via the radiator feed (5) at its lower end . - Which with the electrically conductive base (6) between its conductor loop crosspoints (7a-d) and each coupled to a ground terminal (3a, 3b) vertical radiator (4b-d) and the excitation via the radiator feed (5) vertical radiator (4a), between its conductor loop coupling point (7a) and the radiator feed (5) each have inductively active components (13a-d), so that at the radiator feed (5) at the frequency fo a low-impedance resonance of the character of a series resonance given is. Radiator according to claim 1,
characterized in that
the ring conductor (2) in the horizontal plane and its outer boundary is substantially symmetrical to its center Z designed and its inner boundary is designed in such a way that along the circumference of the ring conductor width B is smaller than 1/4 of the via the center Z of the ring conductor (2) measured horizontal extension of the ring conductor. (2) Emitter according to at least one of claims 1 or 2,
characterized in that
the ring conductor (2) is circular or designed as a regular polygon with N corners and over the circumference L of the circle or at the corners of the N-corner over the circumference of the length (L) of the ring conductor (2) N mutually identical vertical radiator (4a-d) in the same lengthwise extended distances (L / N) of the ring conductor structure from each other via the conductor loop coupling points (7a-d) to the ring conductor (2) galvanically (6) are coupled and the resonance at the frequency fo by design the inductively effective components (13a-d) of the vertical radiator (4a-d) is given. Radiator according to at least one of claims 1 to 3,
characterized in that
for producing the resonance of the ring line radiator (1), the vertical radiators (4a-d) are respectively connected at an interruption point with an inductance (15a-d) of the inductive reactance XL required for this purpose,
and or
that in the vertical radiators (4b-d) inductively active components in all vertical radiators (4a-d) have approximately the same size, so that at resonance in these radiators (4a-d) flow directionally equal currents of approximately the same size. Radiator according to at least one of the preceding claims,
characterized in that
the inductively active components (15a-d) are designed as concentrated inductors (32a-32c) respectively at the lower end of the vertical radiators. Radiator according to at least one of the preceding claims,
characterized in that
the resonant frequency fo is chosen in such a way that the slight detuning of the resonance of the radiator occurring at a slightly higher frequency f in the frequency band of the radiator is thus inductive in the impedance occurring between the radiator feed point (5) and the adjacent ground connection point (3a) in that when a capacitor is connected in parallel between the radiator feed point (5) and the adjacent ground connection point (3a) there is impedance matching to a predetermined target impedance ZL and the radiator feed point (5) forms the antenna connection point (34) of an antenna adapted to ZL. Radiator according to at least one of the preceding claims,
characterized in that
the resonant frequency fo is chosen in such a way that the slight detuning of the resonance of the radiator occurring at a slightly lower frequency f in the frequency band of the radiator, the impedance occurring between radiator feed point (5) and the adjacent ground terminal (3a) is capacitive in such a way in that when an inductance is connected in parallel between the radiator feed point (5) and the adjacent ground connection point (3a) there is impedance matching to a predefined target impedance ZL and the radiator feed point (5) forms the antenna connection point (34) of an antenna adapted to ZL. Radiator according to at least one of the preceding claims,
characterized in that
the ring conductor (2) is designed as a square, at the corners of which a ring line coupling point (7) with a vertical emitter (4, 4a-d) galvanically connected thereto is formed, and three emitters (4, 4b-d) with the electric senior Base (6) for connection to a ground terminal (3b-d) are each connected via an inductor (13b-d) to a ground terminal (3b-d) and a radiator (4, 4a) via an inductance (13a ) is connected to the radiator feed point (5). Radiator according to at least one of the preceding claims,
characterized in that
the resonant frequency fo is chosen to be approximately equal to the center frequency f of the radio service and the sides of the square are approximately equal to λo / 10 and the height h is approximately equal to λo / 20, so that at the radiator feed point (5) impedance matching to a predetermined target impedance ZL prevails and by the latter the antenna connection point (34) is given. Radiator according to at least one of the preceding claims,
characterized in that
the inductors (32a-d) are designed in printed circuit technology on the electrically conductive base plate (6) designed as an electrically conductive printed circuit board, which in each case at one end with the vertical radiator (4, 4a-d) and at the other end with the electric conductive base (6) or also designed on the coated circuit board radiator feed (5) are connected. Radiator according to at least one of the preceding claims,
characterized in that
the inductively effective components (13a-g) necessary for resonance are each given by shaping the vertical radiators (4a-c) in such a way that vertical radiator parts (20) and horizontal radiator parts (21) in the vertical radiators (4a-c) or meandering or oblique radiator parts are present. Radiator according to at least one of the preceding claims,
characterized in that
the electrically conductive base surface (6) running substantially in a base plane (E1) is formed at the location of the ring conductor (2) as an electrically conductive cavity (38) which is open at the top and whose electrically conductive cavity base surface (6a) is in one extending in the cavity depth (12) parallel to and below the base plane (E1) located base plane (E2) and in which the ring conductor (2) in a further horizontal loop level (E) in height h running is introduced above the cavity base surface (6a) and the cavity base surface (6a) covers at least the vertical projection surface of the ring conductor (2) on the base surface plane (E1) below the base surface plane (E2) and the electrically conductive layer Cavity side surfaces (40) at each point have a contour in such a way that a sufficiently large cavity spacing (10) between the ring conductor (2) and the cavity (38) at each point given is. Radiator according to at least one of the preceding claims,
characterized in that
the emitter (1) is designed for the additional reception of circularly polarized satellite radio signals of a satellite service at a frequency fs> f, wherein the ring conductor (2) forms a ring line together with the conductive base (6), so that at the frequency fs a resonance structure in the manner is formed that is set by feeding via the one of the vertical radiator (4d) with radiator feed (5) on the loop, the current distribution of a current line wave in a single direction of rotation, the phase difference over an azimuthal cycle is just 2π, the inductors (15a-d) of the coupled to the conductive ground plane vertical radiator (4a-c) and the one vertical radiator (4d) with radiator feed (5) each have a capacitive element (26) is connected in parallel, so that in each case a dummy element circuit ( 27) is given, which for the service at the frequency f continue to gef ordered inductive action and at the frequency fs for the satellite service has the determining the resonance and the direction of rotation of the rotating wave capacitive effect. Radiator according to at least one of the preceding claims,
characterized in that
in the center Z of the ring conductor (2) along a vertical center line VZ, a vertical rod-shaped antenna for at least one other service is divided into separate conductor pieces by interruption points such that the stretched lengths (14) of the conductor pieces (24) are not greater than 3 / 8 the wavelength λo are selected and the interruption points are bridged by frequency-selective dipole (25), which in the frequency ranges of the other radio services are low-impedance and in the, the emitter (1) with ring conductor (2) associated with high impedance. Radiator according to at least one of the preceding claims,
characterized in that
the ring conductor (2) is essentially given by the boundary of a closed conductive surface and the ring line coupling points (7a, 7b, 7c, 7d) are each formed in the vicinity of this boundary.

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