Switchable broadband antenna

Abstract

A switchable broadband antenna (ANT) with an antenna feed point (SP) for feeding in an input signal, further comprising four antenna paths (AE) connected in parallel with respect to the antenna feed point, each having a matching circuit (AS), a divider circuit (TS), a control circuit (SS), and a dipole antenna element (DP), wherein two dipole antenna elements are arranged in a first polarization direction, and - the respective matching circuit (AS) is configured to establish an impedance match for the input signal between the antenna feed point (SP) and the divider circuit (TS), and - the respective divider circuit (TS) has two divider lines (TL1, TL2) between an input point (EP) and two output points (AP1, AP2), and the divider circuit (TS) is further configuredto symmetrically divide a signal provided to the input point (EP) via the matching circuit (AS) and feed it to the respective output point (AP1, AP2) of the divider circuit (TS), which is connected to the respective dipole antenna element (DP), and - the control circuit (SS) has two electronically controllable impedances (D1, D2), wherein the two electronically controllable impedances (D1, D2) are each arranged in opposite directions, and the control circuit (SS) is configured to provide respective control voltages to the respective electronically controllable impedances (D1, D2) so that different reflection factors are set between the two electronically controllable impedances (D1, D2) in order to switch the signal provided by the matching circuit (AS) and thus control the antenna characteristic of the switchable broadband antenna (ANT).

Description

[0001] The invention relates to a switchable broadband antenna.

[0002] For fifth or sixth generation mobile communications and the latest generation of Wi-Fi, broadband data transmissions using numerous frequency bands are to be used.

[0003] Such broadband data transmissions should be well adapted to a wide variety of applications and have a switchable antenna directional characteristic in order to achieve optimal adaptation of an application to an environment.

[0004] In addition, an antenna should be integrable, i.e. it should not have any external antennas and should be easy to manufacture.

[0005] All of these requirements are not yet met by a single antenna in the current state of the art.

[0006] Currently, broadband antennas have a fixed directional characteristic, whereby the directional characteristic can be switched between different antennas (antenna diversity).

[0007] It is therefore an object of the invention to provide a broadband antenna with switchable characteristics which is simple to manufacture and easy to integrate.

[0008] The object of the invention is achieved by a switchable broadband antenna with an antenna feed point for feeding in an input signal, further comprising four antenna paths connected in parallel with respect to the antenna feed point, each with a matching circuit, a divider circuit, a control circuit and a dipole antenna element, wherein two dipole antenna elements are arranged in a first polarization direction, and the further two dipole antenna elements are arranged in a second polarization direction, which is aligned normal to the first polarization direction, and the respective matching circuit is configured to establish an impedance match for the input signal between the antenna feed point and the divider circuit, and the respective divider circuit has two divider lines between an input point and two output points of the divider circuit with a common reference surface, and the divider circuit is further configured to symmetrically divide a signal provided to the input point via the matching circuit and supply it to the respective output point of the divider circuit, which is connected to the respective dipole antenna element, and the control circuit has two electronically controllable impedances, for each of which at least two predetermined reflection factors can be set, wherein one of the two divider lines of the divider circuit is connected to the reference surface of the divider circuit via one of the two electronically controllable impedances,and the control circuit is configured to provide respective control voltages to the respective electronically controllable impedances, so that different reflection factors are set between the two electronically controllable impedances in order to switch the signal provided by the matching circuit and thus control the antenna characteristic of the switchable broadband antenna.

[0009] This allows the antenna to achieve a very broadband response in the frequency range, for example 4 - 7 GHz, and to switch the dipoles to obtain an adjustable antenna characteristic.

[0010] It is advantageous if the two dipole antenna elements are arranged at a distance of approximately half the wavelength or an integer multiple of half the wavelength of the input signal from each other.

[0011] In difficult environments, the directional characteristic can be switched automatically, i.e. adaptively.

[0012] The existing polarization modes can increase diversity compared to separate antennas.

[0013] Switchable directional characteristics are particularly advantageous for different applications.

[0014] In addition, the directional characteristic can be adjusted only after the antenna has been installed, thus facilitating operation and maintenance and offering a high degree of diversity.

[0015] Furthermore, signals can be generated with at least two such groups that offer a high degree of polarization and spatial diversity.

[0016] As an electronically controllable impedance, for example, a PIN diode, a varactor diode, a field-effect transistor or a MEMS (microelectromechanical system, for example a high-frequency switch) with a corresponding circuit can be used.

[0017] The two electronically controllable impedances each switch between at least two predetermined reflection states of the controllable impedance with respective, different reflection factors using the control voltages provided by the control circuit.

[0018] The respective control voltage is directly related to the desired impedance, which is used to set a respective reflection factor at the location of the controllable impedance on the line.

[0019] The reflection factors on both divider lines serve to control the dipole antenna accordingly and thus obtain an adjustable antenna characteristic.

[0020] The respective required control voltage is predetermined in connection with the respective controllable impedance implemented and optionally with a necessary circuit for controlling the selected controllable impedance, which is included in the control circuit.

[0021] The term reflection factor or reflection coefficient is the amplitude ratio between reflected and incident wave at the transition to another propagation medium, such as a change in the characteristic impedance in a line, or at a disturbance point, which can be formed by the controllable impedance.

[0022] However, the reflection factors of the respective controllable impedance can also be in a range between "-1" and "+1", which represent a short circuit or an open circuit, in order to ensure that the reflections of the signal in the divider lines overlap constructively or destructively.

[0023] A reflection factor of "-1" corresponds to a short circuit, i.e. a total reflection with a phase inversion at the short-circuited end of a line.

[0024] A reflection factor of "+1" corresponds to an open circuit, i.e. a total reflection without phase inversion at the open end of a line.

[0025] A reflection factor of "0" corresponds to an ideal match to the characteristic impedance of the line, so no reflection occurs.

[0026] In a preferred embodiment, more than two predetermined reflection factors can also be set, such as three, four or more predetermined reflection factors.

[0027] For example, with three predefined reflection states of the controllable impedance or its reflection factors, it is possible to switch between the "logical" states "-1", "0" and "+1" for each controllable impedance.

[0028] A "logical" state for the controllable impedance corresponds to a predetermined reflection state or reflection factor of the controllable impedance, which includes a reflection magnitude and a reflection phase value.

[0029] This can be used to obtain an even more variable adjustable antenna characteristic.

[0030] Preferably, there is a distance of greater than one in the magnitude of the reflection factors between these two reflection states.

[0031] This can be achieved in a simple way by having the two reflection factors of the electronically controllable impedances differ, for example, by the sign, such as a reflection factor of "-1" and "+1", i.e. an inverse phase between the electronically controllable impedances.

[0032] Optionally, the controllable reflection factor can be approximately the same in magnitude and preferably have a magnitude greater than 0.5.

[0033] In the present context, a "counter-rotating arrangement" of PIN diodes as electronically controllable impedances means that the two reflection factors of the electronically controllable impedances differ by the sign, thus causing a reflection in the signals fed into the two divider lines with a difference of 180° compared to the respective other signal of the other divider line, in order to achieve that the reflections of the signal in the two divider lines respectively overlap constructively or destructively.

[0034] In other words, signals fed into the two divider lines are reflected in opposite directions at the electronically controllable impedances, which can be achieved with oppositely modulated reflection factors of the electronically controllable impedances in the respective divider lines.

[0035] The control circuit provides, for example, predefined control voltages to the respective electronically controllable impedance, which configure the electronically controllable impedance so that a predetermined reflection factor is set, for example "-1" and "+1".

[0036] In a further development of the invention, it is provided that in the respective antenna path the divider circuit is realized on a circuit carrier with a first side and a second side, and the two divider lines are arranged on the first side and the common reference surface on the second side.

[0037] This makes the construction of the antenna much easier.

[0038] A conventional circuit carrier material for a double-sided printed circuit board such as FR4 can be used.

[0039] In a further development of the invention, it is provided that in the respective antenna path the dipole antenna elements are also arranged on the circuit carrier of the divider circuit.

[0040] This further simplifies the construction of the antenna.

[0041] In a further development of the invention, it is provided that the dipole antenna elements are arranged on the second side of the circuit carrier in the respective antenna path.

[0042] This makes the construction of the antenna much easier.

[0043] In a further development of the invention, it is provided that in the respective antenna path the dipole antenna elements are connected to the reference surface of the divider circuit.

[0044] This makes the construction of the antenna much easier.

[0045] In a further development of the invention, it is provided that in the respective antenna path, the reference surface of the divider circuit has an electrically non-conductive separating strip which extends between the output points of the two divider lines towards the input point.

[0046] This results in a particularly high symmetry of the antenna, which has a positive effect on a homogeneous antenna pattern.

[0047] In a further development of the invention, it is provided that a feed circuit for feeding and controlling the two electronically controllable impedances of the control circuit is inserted into the respective antenna path.

[0048] This makes it particularly easy to provide the control voltage for controlling the electronically controllable impedances.

[0049] It is clear that different control voltages are used for the two electronically controllable impedances used, depending on whether they are operated in the forward direction or in the reverse direction, since the electronically controllable impedances are operated with different polarity (conductive or blocking).

[0050] In a further development of the invention, it is provided that the feed circuit in the divider circuit is inserted before the feed point in the respective antenna path.

[0051] This makes it particularly easy to provide the control voltage for controlling the electronically controllable impedances.

[0052] In a further development of the invention, it is provided that in the respective antenna path the output points of the divider circuit are each connected to the dipole antenna element via an ohmic resistor.

[0053] This makes it easy to adjust the antenna pattern to suit a specific application. The resistance makes it particularly easy to adapt the antenna to the requirements of different applications.

[0054] In a further development of the invention, it is provided that more than four antenna paths (AE) connected in parallel with respect to the antenna feed point are arranged, each with a matching circuit (AS), a divider circuit (TS), a control circuit (SS) and a dipole antenna element (DP).

[0055] This allows for an even more flexible controllable antenna with regard to the resulting directional characteristic, since more antenna paths can be controlled individually.

[0056] An embodiment of the invention will now be explained in more detail with reference to the following figures. The figures show Fig. 1 shows a circuit carrier with an antenna according to the invention. Fig. 2 shows an equivalent circuit diagram for an antenna element of the antenna according to the invention. Fig. 3a shows a diagram with a feed point of the antenna. Fig. 3b shows a diagram of the circuit carrier at the transition between a matching circuit and a feed circuit. Fig. 3c shows simulated field strengths of the circuit carrier in the region of an antenna element. Fig. 3d shows a diagram of a divider circuit. Figs. 4a to 4d show radiation patterns of the antenna in various radiation characteristics. Figs. 5a and 5b show transmission patterns of the antenna in various radiation configurations. Figs. 6a and 6b show insulation patterns of the antenna in various radiation configurations. Figs. 7a and 7b show emitted power patterns of the antenna in various radiation configurations. Fig. 8a to 8fRadiation patterns of the antenna at different frequencies, Fig.9a and 9b simulated field strength distributions of the antenna in different radiation configurations, Fig. 9c and 9d detailed enlargements of simulated field strength distributions of the previous figure. .

[0057] Fig. 1 shows a circuit with a switchable broadband antenna ANT according to the invention.

[0058] The antenna ANT has an antenna feed point SP for feeding in an input signal, for example in the form of a corresponding radio frequency connector.

[0059] Furthermore, four antenna paths AE connected in parallel with respect to the antenna feed point are included.

[0060] The antenna paths AE each have a matching circuit AS, a divider circuit TS, a control circuit SS and a dipole antenna element DP.

[0061] Two dipole antenna elements are arranged in a first polarization direction and at a distance of approximately an integer multiple of half the wavelength of the input signal from each other.

[0062] The other two dipole antenna elements are arranged in a second polarization direction, which is aligned normal to the first polarization direction, and at a distance of approximately an integer multiple of half the wavelength of the input signal from each other.

[0063] The dipole antenna DP has differential feed points on its antenna elements.

[0064] The electronically controllable impedances D1, D2 in the form of PIN diodes activate one of the two signal paths of the divider circuit TS and deactivate the other.

[0065] This allows the direction in which the signal is fed to the differential feed point of the antenna ANT to be decided.

[0066] In one embodiment, two electronically controllable impedances are used, one or the other of which is activated and switched as a short circuit.

[0067] Essentially, one of the signal paths, i.e. the respective divider line TL1, TL2, is deactivated by line transformations starting from the activated PIN diode D1, D2 generating suitable impedances at the node point and at the respective side of the differential antenna feed point.

[0068] At the node point, an open-circuit-like impedance is generated on this side, while at the antenna feed point, it is a short-circuit-like impedance.

[0069] The optimal parameters of the signal paths, such as impedances and lengths of the line segments, depend on the impedance of the antenna feed point and the desired input impedance at the node.

[0070] The activated path then carries the signal from the node to the other side of the differential feed point, unaffected by the deactivated path.

[0071] Due to the selected position of the high-frequency switches D1, D2 and the line parameters, an extremely broadband polarity switching can be generated. The respective matching circuit AS is configured to produce an impedance match for the input signal between the antenna feed point SP and the divider circuit TS.

[0072] The respective divider circuit TS has two divider lines TL1, TL2 between an input point EP and two output points AP1, AP2 of the divider circuit TS with a common reference surface BF.

[0073] The divider circuit TS is further configured to symmetrically divide a signal provided to the input point EP via the matching circuit AS and to supply it to the respective output point AP1, AP2 of the divider circuit TS, which is connected to the respective dipole antenna element DP.

[0074] The two output points AP1, AP2 of the divider circuit TS are connected by a connecting line TV, creating a signal divider.

[0075] The control circuit SS has two electronically controllable impedances D1, D2, wherein one of the two divider lines TL1, TL2 of the divider circuit TS is connected to the reference surface BF of the divider circuit TS via one of the two electronically controllable impedances D1, D2.

[0076] The two PIN diodes D1, D2 are arranged in opposite directions.

[0077] The control circuit SS is configured to provide a control DC voltage SS to the respective electronically controllable impedances D1, D2 in order to switch the signal provided by the matching circuit AS and thus to control the antenna characteristic of the switchable broadband antenna ANT.

[0078] The antenna ANT has four antenna paths AE which are connected in parallel.

[0079] In the respective antenna path AE, the divider circuit TS is realized on a circuit carrier with a first side and a second side, for example FR4.

[0080] The two divider lines TL1, TL2 are arranged on the first side and the common reference surface BF is arranged on the second side.

[0081] In the respective antenna path AE, the dipole antenna elements DP are also arranged on the circuit carrier of the divider circuit TS, namely on the second side of the circuit carrier, and the dipole antenna elements DP are connected to the reference surface BF of the divider circuit TS.

[0082] The reference surface BF of the divider circuit TS has an electrically non-conductive separating strip ST, i.e. a slot, which extends between the output

[0083] Points AP1, AP2 of the two divider lines TL1, TL2 to the input point EP.

[0084] Furthermore, a feed circuit ES for feeding and controlling the two electronically controllable impedances D1, D2 of the control circuit SS is inserted into the respective antenna path AE, in this example between the matching circuit AS and the divider circuit TS, i.e. before the feed point EP in the respective antenna path AE.

[0085] Optionally, in the respective antenna path AE, the output points AP1, AP2 of the divider circuit TS can each be connected to the dipole antenna element DP via an ohmic resistor.

[0086] Fig. 2 represents an equivalent circuit diagram for an antenna element of the antenna according to the invention.

[0087] An input signal is fed into the antenna feed point SP.

[0088] The matching circuit AS adjusts the impedances between the antenna feed point SP and the divider circuit TS accordingly and also takes into account a total of four antenna paths AE connected in parallel.

[0089] The matching circuit AS transforms the characteristic impedance of the divider circuit TS from 50 ohms to an amount of 200 ohms for a single antenna path AE.

[0090] The four antenna paths, each with an input resistance of 200 ohms, are connected in parallel, which in turn results in an input resistance of 50 ohms for the antenna ANT at the antenna feed point SP.

[0091] The ES supply circuit enables the supply and control of the two electronically controllable impedances D1, D2 in the form of PIN diodes by means of a control voltage (bias).

[0092] The control voltage is provided by the control circuit SS in the form of a DC voltage.

[0093] The divider is formed by two divider lines TL1, TL2 and a connecting line TV between the input point EP and the output points AP1, AP2.

[0094] The dipole halves of the dipole DP are each connected to one of the output points AP1, AP2.

[0095] Fig. 3a shows a spatial representation of the antenna ANT with the antenna feed point SP.

[0096] Fig. 3b shows a spatial representation of the circuit carrier at the transition between an adaptation circuit AS and a feed-in circuit ES.

[0097] Fig. 3c shows a representation of simulated field strengths of the circuit carrier in the area of ​​an antenna element.

[0098] Fig. 3d shows a representation of the divider circuit TS, comprising two electronically controllable impedances D1, D2 of the control circuit SS.

[0099] Each of the two divider lines TL1, TL2 of the divider circuit TS is connected to the reference surface BF of the divider circuit TS via one of the two electronically controllable impedances D1, D2.

[0100] The lines of the two divider lines TL1, TL2 are located on the first side of the circuit board, and the reference surface BF and the dipole DP are located on the second side of the circuit board.

[0101] The reference surface BF of the divider circuit TS has an electrically non-conductive separating strip ST, i.e. a slot.

[0102] The slot extends between the output points AP1, AP2 of the two divider lines TL1, TL2 to the input point EP.

[0103] Depending on the design, the length of the slot can be only approximately the width of the dipole DP, or it can extend to the input point EP.

[0104] The two PIN diodes D1, D2 are each arranged in opposite directions with respect to the reference surface BF and are connected to it, for example with a through-hole.

[0105] Fig. 4a to Fig. 4d represent radiation patterns of the antenna in different radiation characteristics.

[0106] The antenna's radiation patterns show the elevation over the azimuth angle, with four options for the respective radiation angle being adjustable: Wide in azimuth and narrow in elevation Narrow in azimuth and wide in elevation Narrow in azimuth and narrow in elevation Wide in azimuth and elevation with a zero in the normal axis of the dipoles

[0107] All four variants can be operated in two polarization modes.

[0108] These variants cover a wide range of directional characteristics that are advantageous for different applications.

[0109] In addition, at least two such groups can generate signals that offer a high degree of polarization and spatial diversity.

[0110] This applies to each of the four adjustable directional patterns. High diversity is crucial for modern wireless systems with MIMO functionality.

[0111] In Fig. 4a a narrow radiation characteristic of the antenna can be seen.

[0112] In Fig. 4ba wide radiation characteristic of the antenna can be seen.

[0113] In Fig. 4c The antenna's radiation pattern can be seen in the form of a horizontal stripe.

[0114] In Fig. 4d The antenna's radiation pattern can be seen in the form of a vertical stripe.

[0115] The electronic switching of the directional characteristics and polarization modes makes it very easy to select the best antenna configuration, which can also be done after installation.

[0116] The result is a controllable antenna in a small design that can be easily integrated into radio products.

[0117] Due to the high bandwidth, 5 GHz and 6 GHz WLAN can be covered with the same antenna.

[0118] Fig. 5a and Fig. 5b show passband diagrams of the antenna in different radiation configurations.

[0119] The desired frequency ranges for the target applications are also shown in the diagrams.

[0120] In Fig. 5a The antenna's passband S-parameters can be seen in a stripe configuration.

[0121] The transmission S-parameters between a first antenna (first part of the index) with vertical stripe configurations V1, V2 or horizontal stripe configuration H1, H2, and a second antenna (second part of the index) with vertical stripe configurations V1, V2 or horizontal stripe configuration H1, H2 are shown.

[0122] In Fig. 5b The antenna's passband S-parameters are visible in a narrow / wide configuration.

[0123] They are the pass-through S-parameters between a first antenna (first part of the index) with narrow configuration N1, N2 or wide configuration W1, W2, and a second antenna (second part of the index) with narrow configuration N1, N2 or wide configuration W1, W2.

[0124] Fig. 6a and Fig. 6b show isolation diagrams of the antenna in different radiation configurations for an antenna bandwidth of approximately 4-7 GHz.

[0125] In Fig. 6a Isolation S-parameters of the antenna can be seen in a stripe configuration.

[0126] The transmission S-parameters between a first antenna (first part of the index) with vertical stripe configurations V1, V2 or horizontal stripe configuration H1, H2, and a second antenna (second part of the index) with vertical stripe configurations V1, V2 or horizontal stripe configuration H1, H2 are shown.

[0127] In Fig. 6bIsolation S-parameters of the antenna in a narrow / wide configuration can be seen.

[0128] They are the pass-through S-parameters between a first antenna (first part of the index) with narrow configuration N1, N2 or wide configuration W1, W2, and a second antenna (second part of the index) with narrow configuration N1, N2 or wide configuration W1, W2.

[0129] Fig. 7a and Fig. 7b show emitted power diagrams of the antenna in different radiation configurations for an antenna bandwidth of approximately 4-7 GHz.

[0130] In Fig. 7a Emitted power of the antenna can be seen in a narrow / wide configuration.

[0131] The performances for narrow antenna characteristics N1, N2 and wide antenna characteristics W1, W2 are shown.

[0132] In Fig. 7b Emitted power from the antenna can be seen in a stripe configuration.

[0133] The performances for vertical stripe configurations V1, V2 and horizontal stripe configuration H1, H2 are shown.

[0134] Fig. 8a to Fig. 8f show radiation patterns of the antenna at different frequencies.

[0135] Fig. 8a shows a radiation field distribution at a frequency of 4 GHz.

[0136] Fig. 8b shows a radiation field distribution at a frequency of 5.1 GHz.

[0137] Fig. 8c shows a radiation field distribution at a frequency of 5.9 GHz.

[0138] Fig. 8d shows a radiation field distribution at a frequency of 6.5 GHz.

[0139] Fig. 8e shows a radiation field distribution at a frequency of 7.2 GHz.

[0140] Fig. 8f shows a radiation field distribution at a frequency of 7.5 GHz.

[0141] Fig. 9a and Fig. 9bshow simulated field strength distributions of the antenna in different radiation configurations, in which two spatially distributed maxima (spatial diversity) and different radiation directions (pattern diversity) are recognizable.

[0142] Fig. 9c and Fig. 9d show simulated field strength distributions of the previous figures in an enlarged view, in which different polarizations (polarization diversity) can be seen, whereby the antennas have the same polarization or the opposite polarization (left hand circular polarization, LHCP for short, or right hand circular polarization, RHCP for short).

[0143] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included. List of reference symbols

[0144] AZ Azimuth AE Antenna element, antenna path AP1, AP2 Output point of the divider circuit AS Matching circuit BF Reference surface, ground C Capacitor DP Dipole antenna elements EL Elevation EP Input point of the divider circuit ES Feed circuit f Frequency L1, L2 Coil P, P_N1, P_N2, P_W1, P_W2 Radiated power in watts SP Feed point of the antenna SS Control circuit TL1, TL2 Divider line TV Divider connecting line TS Divider circuit S_V1V1, S_V2V2, S_H1H1, S_H2H2, S_N1N1, S_N2N2, SW1W1, S_W2W2, S_V1V1, S_V1H2, S_V1H1, S_V2H2, S_V2H1, S_H2H1, S_N2W2, S_N2N1, S_N1W1,S_W2N1, S_W2W1, S_N1W1 ST S parameters

Claims

1. A switchable broadband antenna (ANT) with an antenna feed point (SP) for feeding in an input signal, further comprising four antenna paths (AE) connected in parallel with respect to the antenna feed point, each having a matching circuit (AS), a divider circuit (TS), a control circuit (SS), and a dipole antenna element (DP), wherein two dipole antenna elements are arranged in a first polarization direction, and the further two dipole antenna elements are arranged in a second polarization direction, which is aligned perpendicular to the first polarization direction, and - the respective matching circuit (AS) is configured to establish an impedance match for the input signal between the antenna feed point (SP) and the divider circuit (TS), and - the respective divider circuit (TS) has two divider lines (TL1, TL2) between an input point (EP) and two starting points (AP1,AP2) of the divider circuit (TS) having a common reference surface (BF), and the divider circuit (TS) is further configured to symmetrically divide a signal provided to the input point (EP) via the matching circuit (AS) and supply it to the respective output point (AP1, AP2) of the divider circuit (TS), which is connected to the respective dipole antenna element (DP), and - the control circuit (SS) has two electronically controllable impedances (D1, D2), for each of which at least two predetermined reflection factors can be set, wherein one of the two divider lines (TL1, TL2) of the divider circuit (TS) is connected to the reference surface (BF) of the divider circuit (TS) via one of the two electronically controllable impedances (D1, D2), wherein the two electronically controllable impedances (D1, D2) are each arranged in opposite directions, and the Control circuit (SS) is designed toto provide respective control voltages to the respective electronically controllable impedances (D1, D2) so that different reflection factors are set between the two electronically controllable impedances (D1, D2) in order to switch the signal provided by the matching circuit (AS) and thus control the antenna characteristic of the switchable broadband antenna (ANT).

2. Broadband antenna (ANT) according to the preceding claim, wherein in the respective antenna path (AE) the divider circuit (TS) is realized on a circuit carrier with a first side and a second side, and the two divider lines (TL1, TL2) are arranged on the first side and the common reference surface (BF) on the second side.

3. Broadband antenna according to the preceding claim, wherein in the respective antenna path (AE) the dipole antenna elements (DP) are also arranged on the circuit carrier of the divider circuit (TS).

4. Broadband antenna according to the preceding claim, wherein in the respective antenna path (AE) the dipole antenna elements (DP) are arranged on the second side of the circuit carrier.

5. Broadband antenna according to the preceding claim, wherein in the respective antenna path (AE) the dipole antenna elements (DP) are connected to the reference surface (BF) of the divider circuit (TS).

6. Broadband antenna according to the preceding claim, wherein in the respective antenna path (AE) the reference surface (BF) of the divider circuit (TS) has an electrically non-conductive separating strip (ST) which extends between the output points (AP1, AP2) of the two divider lines (TL1, TL2) to the input point (EP).

7. Broadband antenna according to one of the preceding claims, wherein a feed circuit (ES) for feeding and controlling the two electronically controllable impedances (D1, D2) of the control circuit (SS) is inserted into the respective antenna path (AE).

8. Broadband antenna according to the preceding claim, wherein the feed circuit (ES) in the divider circuit (TS) is inserted before the feed point (EP) in the respective antenna path (AE).

9. Broadband antenna according to one of the preceding claims, wherein in the respective antenna path (AE) the output points (AP1, AP2) of the divider circuit (TS) are each connected to the dipole antenna element (DP) via an ohmic resistor.

10. Broadband antenna according to one of the preceding claims, wherein more than four antenna paths (AE) connected in parallel with respect to the antenna feed point are arranged, each with a matching circuit (AS), a divider circuit (TS), a control circuit (SS) and a dipole antenna element (DP).

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