WO2022038003A1

WO2022038003A1 - Antenna

Info

Publication number: WO2022038003A1
Application number: PCT/EP2021/072321
Authority: WO
Inventors: Thomas Bolz; Michael Wilhelm ENGELS; Peter HILDENHAGEN; Benno JACOBS; Frank PANNES; Thomas PODREBERSEK; Matthias Rittweger
Original assignee: Hagenuk Marinekommunikation Gmbh; Thyssenkrupp Ag
Priority date: 2020-08-19
Filing date: 2021-08-10
Publication date: 2022-02-24
Also published as: DE102020210513A1

Abstract

The invention relates to an antenna (20) having a first hollow emitter (22a) and a second hollow emitter (22b). The hollow emitters are each designed to emit and/or receive electromagnetic radiation. The first hollow emitter (22a) is arranged sequentially with respect to the second hollow emitter (22b). The antenna further has an electrical component (24) and an electrical line, which is guided through the first and the second hollow emitter (22b) in order to make contact with the electrical component (24). The electrical line (28) has a shielding (28a), which is connected to the second hollow emitter (22b) by means of an electrical resistor (30).

Description

antenna

description

The invention relates to an antenna made up of tube-like radiators, through which radiators an electrical line is passed. Tube-like radiators are referred to below as hollow radiators. Compared to conventional antennas, which form a coaxial conductor due to their structure, this antenna has reduced parasitic resonances. The antenna is, for example, a dipole antenna with an electrical line routed through both radiators, the dipole antenna having an arrangement for reducing parasitic resonances. In other words, a termination to avoid internal parasitic resonances in antennas with internal cable connections along the antenna is shown.

For example, in the case of multifunction antennas, which consist of several individual antennas, antennas are arranged sequentially and thus one above the other in the main direction of use. The feeder cables (typically coaxial cables) from one antenna are routed through another antenna.

In particular if the antenna through which the feeder cable is routed is a dipole, the dipole can be short-circuited at least at a specific frequency to be radiated (resonant frequency). In other words, with open coaxial lines, even if they are caused by the dipole and an outer conductor of the coaxial line passed through and are not desired, an impedance transformation takes place depending on the frequency of the signal that is transmitted with the coaxial line. An open line end can be transformed into a high-frequency short circuit by means of a quarter-wave line transformation. This means that the (almost) infinite impedance at the open end of the coaxial line can be transformed into a short circuit (impedance is (almost) 0 ohms) at the feeding end of the coaxial line when operated with an AC voltage of the resonant frequency. The resonant frequency is at the wavelength (lambda) corresponding to the length of the coaxial line, or at odd multiples of the frequencies at which the open At the end of the coaxial line is transformed into an open circuit at the lower end of the coaxial line, are even multiples of ¹ A. This means that near the resonant frequencies, little or no energy is radiated by the dipole.

This problem has already been discussed in DE 102 39 874 B3. Here, three radiator elements are fed by means of coaxial lines lying one inside the other in order to prevent impedance transformation. More precisely, three radiating elements are used, which are combined in such a way that two radiating elements each form a dipole for a specific frequency range. One radiator element is decoupled by lambda/4 resonances, the other two radiator elements form the dipole. However, this solution can only be used for certain frequency ranges for which the lengths of the radiating elements are optimized and, since at least three radiating elements are required to form the antenna, requires a) a lot of space, b) a comparatively large amount of hardware in the form of the additional radiating element and c) a diplexer or a crossover network.

The object of the present invention is therefore to create an improved concept for antennas, in particular multifunctional antennas.

The object is solved by the subject matter of the independent patent claims. Further advantageous embodiments are the subject matter of the dependent patent claims.

Exemplary embodiments show an antenna with a first hollow radiator and a second hollow radiator, which are each designed to emit and/or receive electromagnetic radiation, the first hollow radiator being arranged sequentially with respect to the second hollow radiator (ie one behind the other in the longitudinal direction). Such an arrangement of two antennas is also referred to as a dipole. An electrical line that makes contact with an electrical component is passed through the first and the second hollow radiator. The electrical component is, for example, a further antenna, which can be operated in addition to, and advantageously independently of, the first and second radiators. the end From a different perspective, the antenna can also be referred to as a multifunction antenna, with the first and second radiators together forming a first antenna and the further radiator forming a second antenna. However, the electrical component can also be any other electrical load.

The electrical line has a shield which is connected to the second hollow radiator by means of an electrical resistor. The electrical resistance designates both a direct voltage resistance (also referred to as effective resistance) and an alternating voltage resistance (also referred to as reactance or inductive or capacitive resistance), e.g. a capacitor (capacitance) or a coil (inductance). An electrical line that has a shield is, for example, a coaxial cable. The first and the second hollow radiator can be excited with a further electrical line, for example also a coaxial cable.

In this disclosure, the term coaxial cable is used for the electrical line (feed line) that contacts the electrical component. A part of the coaxial cable, namely the shielding (also known as the outer conductor), forms a coaxial line with the radiators. In order to be able to tell the two lines apart, the different terms coaxial cable and coaxial line are used. However, it should be noted that the coaxial cable is only one way of forming the electrical line. A coaxial cable typically has an inner conductor and an outer conductor. However, it is also possible for several inner conductors to be routed in one outer conductor. For this reason, the general term "electrical line" is used, which accordingly has one or more inner conductors and a shield (outer conductor).

The antenna may exhibit the absence of a crossover network, in particular a diplexer. This enables a smaller design of the antenna.

The idea is to terminate at least one of the resulting coaxial lines from the shielding (inner conductor of the resulting coaxial line) and the first or second radiator (each outer conductor of the resulting coaxial lines) using the resistor. This means that there is an electrical connection between the shield and the first and/or the second radiator are established via the resistor. If the resistor is chosen correctly, the impedance transformation into a high-frequency short circuit is prevented. The resulting coaxial line appears infinitely long due to a resistance that corresponds to the characteristic impedance of the parasitic coaxial waveguide, so that the coaxial line does not form any reflections at its open end and thus no high-frequency short circuit can form either. Alternatively, the resistance (here an AC voltage resistance) can also be selected in such a way that the resonant frequency is outside the frequency range of the first and second radiators (ie the dipole) in which the dipole is operated. Likewise, DC voltage resistors and AC voltage resistors can be combined in a resistor circuit. The resulting coaxial line is also referred to as a parasitic coaxial line.

If a pure DC voltage resistance is used, this advantageously corresponds approximately to the (line) characteristic impedance of the resulting coaxial line. The characteristic impedance can also be deliberately chosen to be slightly larger in order to keep the power loss in the ohmic resistance lower. If a resistance circuit as described below is used, the resulting complex resistance must be selected depending on the requirements of the antenna, i.e. in particular depending on the frequency band into which the resonant frequency is to be shifted.

In exemplary embodiments, the first hollow radiator and/or the second hollow radiator comprises a helix antenna. If a radiator of the dipole is designed as a helical antenna, the dipole can also emit circularly polarized waves in addition to its actual function, typically the emission of signals as vertically polarized waves. For this purpose, the helix antenna can be operated with a signal that differs from the signal with which the dipole is operated. Both signals can then be emitted independently of one another. In particular, the signal driving the helical antenna is fed into each of the helical turns with a phase shift of every 360 degrees divided by the number of helical turns. Furthermore, it should be noted that the solution presented in DE 102 39 874 B3 cited at the outset does not work with a helix antenna.

In exemplary embodiments, the resistor is arranged on the second hollow radiator, advantageously on an end face of the same, at which the electrical line emerges from the second hollow radiator. The second hollow radiator is the upper radiator, i.e. the electrical cable is then routed through both hollow radiators before the shielding of the electrical cable is connected to the second hollow radiator. This is advantageous because the antenna is still functional even if the lower radiator (first hollow radiator) transforms a short circuit to the middle, i.e. between the first and the second hollow radiator. If the electrical resistance is arranged at a different point, then the open end of the coaxial line transforms into the resistance in the form of a reactance and both resistances form a parallel circuit which then transforms into a complex impedance in the direction of the feed. This is also possible, but it is more complex to determine (or select) the correct electrical resistance.

Exemplary embodiments show that the resistor is part of a resistor circuit, the resistor being a DC resistor and the resistor circuit further comprising an AC resistor. The shield is electrically connected to the hollow radiator by means of the resistive circuit. This is advantageous because the resonant frequency can be shifted into a frequency range in which the antenna is not operated by means of the alternating voltage resistance. As a result, less power is dropped at the DC voltage resistor, so that, conversely, more power can be radiated. However, depending on the application, it is possible that the resonant frequency cannot keep a sufficient distance from the frequency range in which the antenna is operated. Then the radiation of the signal is also impaired at frequencies that are close to the resonance frequency. When the dipole is operated at these frequencies, the contribution of the DC resistance to the total resistance of the resistive circuit can improve the radiation of the signal. It is true that the DC resistance itself also dampens the radiation of the signal, since power drops at the DC resistance, but this attenuation is not as serious as the total reflection of the signal due to the impedance transformation.

In exemplary embodiments, the resistor is part of a resistor network, with the resistor network having a further resistor which is (electrically) arranged in parallel with the resistor. In this way, the current flow is divided across the resistors so that (with the same choice of resistors) there is a symmetrical current flow. Thus, the power that is dropped across a resistor is reduced. The resistor therefore does not get as hot and has a longer service life. Furthermore, the radiation characteristics are less affected with a symmetrical and parallel distribution of the current of the signal on the hollow radiator than with a punctiform superimposition.

Analogously, a method for producing an antenna is shown with the following steps: providing a first hollow radiator and a second hollow radiator, which are each designed to emit and/or receive electromagnetic radiation; arranging the first and second hollow radiators sequentially;

providing an electrical component; passing an electrical line through the first hollow radiator and the second hollow radiator; contacting the electrical component with the electrical line; Electrically connecting a shielding of the electrical line to the second hollow radiator by means of an electrical resistor.

Preferred embodiments of the present invention are explained below with reference to the accompanying drawings. Show it:

FIG. 1 shows a schematic representation of an antenna in an embodiment, wherein FIG. 1a shows a schematic plan view and FIG. 1b shows a schematic sectional representation of the antenna;

2 shows a schematic representation of the antenna in further exemplary embodiments, with FIG. 2a showing a schematic top view and FIG. 2b a schematic sectional representation of the antenna, and with FIG. 2c showing an optional exemplary resistor circuit of the antenna. Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical elements, objects and/or structures that have the same function or have the same effect are provided with the same reference symbols in the different figures, so that the elements shown in different exemplary embodiments Description of these elements is interchangeable or can be applied to each other.

1 shows a schematic representation of an antenna 20 from two perspectives. FIG. 1a discloses a plan view of the antenna 20 and FIG. 1b shows a schematic sectional illustration along the section plane A-A, which is drawn in FIG. 1a. The antenna 20 will now be described with reference to both drawings. The antenna 20 has a first hollow radiator 22a and a second hollow radiator 22b. The hollow radiators 22 are designed to emit and/or receive electromagnetic radiation. An electrical component 24 is arranged (in the main direction of use) above the two hollow radiators 22. The electrical component 24 is not shown in FIG. 1a for reasons of clarity.

Such a sequential arrangement of two hollow radiators 22a, 22b, which are excited at two opposite end faces 26a, 26b with a 180° phase-shifted signal, is also referred to as a dipole.

An electrical line 28 is routed through the first and the second hollow radiator 22 in order to make (electrical) contact with the electrical component 24 . The electrical line 28 has a shield 28a and at least one signal line 28b. For reasons of clarity, however, only one signal line is referred to below. At least the signal line 28b is electrically connected to the electrical component 24 . However, it is also possible to additionally connect the shielding 28a to the electrical component 24 .

This arrangement now results in two coaxial lines. The first coaxial line has the first hollow radiator 22a as the outer conductor and the inner conductor shield 28a. The second coaxial line has the second hollow radiator 22b as the outer conductor and the shielding 28a as the inner conductor. The two hollow radiators are each fed on facing end faces 26a, 26b. The ends of the resulting coaxial lines are accordingly located on the opposite end faces 26c, 26d of the corresponding coaxial line. If the coaxial line is now excited with a high-frequency signal whose wavelength corresponds to a quarter of the length of the coaxial line, this leads to a low-impedance connection between the corresponding hollow radiator 22a, 22b and the shielding 28a at the point at which the hollow radiators are fed. The consequence of this is that the first and the second hollow radiator cannot emit signals with frequencies that are close to the resonance frequencies.

For this reason, the shielding 28a is connected to the second hollow radiator 22b by means of an electrical resistor 30. Although the electrical resistance 30 leads to an attenuation of the signal during emission, this is less than the influence of the impedance transformation on the emission of the signal. Furthermore, the influence of the damping can be reduced with a resistance circuit described below with reference to FIG. 2c.

The resistor 30 is placed at the open end of the resulting coaxial line of the second hollow radiator 22b and the shield 28a. The open end is located on the end face 26d of the second hollow radiator 22b, which is opposite the electrical component 24. The arrangement of the resistor at the end of the resulting coaxial line is advantageous in that no new open coaxial line is created between the resistor and the end of the resulting coaxial line. Furthermore, the resistor can additionally or alternatively also be arranged between the shielding 28a and the first waveguide 22a. This would then advantageously also be at the open end of the resulting coaxial line, which is located at the end face 26c of the first waveguide 22a. Since the arrangement of the resistor on one of the two resulting coaxial lines means that at least the hollow radiator that is in contact with the electrical resistor remains active and only the other hollow radiator is short-circuited with the shielding, which means that the antenna at least still functions as a monopole it is not absolutely necessary to also terminate the other of the two hollow radiators, ie to connect it to the shielding 28a with a resistor.

2a and 2b show the antenna 20 in further exemplary embodiments. However, only the differences from FIGS. 1a and 1b are presented. The resistor 30 is part of a resistor network comprising the resistor 30 and the further resistor 30'. The arrangement of any number of other resistors in the network is possible. The resistor 30 and the additional resistor 30', if any additional resistors are arranged in the network, including any additional resistors, are arranged in parallel between the shielding 28a and the second hollow radiator 22b.

Advantageously, the resistor 30 and the further resistor 30' and optionally any further resistors are arranged symmetrically. I.e. a distance or, in the case of a round hollow radiator, an angle between the resistors is the same in each case. The explanations for the resistor 30 can be applied analogously to the individual resistors of the resistor network. Furthermore, the symmetry also relates to the resistance value of the resistors. This means that the parallel resistors advantageously have the same resistance value, in particular the resistance circuits described below each have the same total resistance if the resistance circuits are arranged in a resistance network.

2c shows a resistance circuit 32. The resistance circuit comprises a plurality of resistances, in particular a combination of ohmic and reactive resistances. Here the resistor 30 as well as a capacitor 30a and a coil 30b are shown as further AC resistors. The resistance circuit is connected between the shielding 28a and the second hollow radiator 22b instead of the resistor 30 from FIG. 1a, FIG. 1b or FIG. 2a, FIG. 2b. To maintain symmetry, the additional resistor 30' should also be replaced with the same resistor circuit. This also applies to any other resistors. With such a resistance circuit, which also has at least one AC voltage resistance, the resonant frequency of the resulting coaxial line can be shifted to a frequency range of of the antenna is not used to radiate signals. The use of the resistance circuit is advantageous in order to be able to reduce the direct voltage resistance and thus to reduce the attenuation of the signal to be radiated by the direct voltage resistance.

Although the resistance circuit can be determined by calculation, it is more practical to determine it by measurement. In this way, the input resistance can be measured over the frequency between the two hollow radiators. The shift of the resonance frequency by exchanging the reactive elements is observed and thus optimized towards the desired resonance frequency.

Although some aspects have been described in the context of a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Similarly, aspects that have been described in connection with or as a method step also represent a description of a corresponding block or detail or feature of a corresponding device.

The embodiments described above are merely illustrative of the principles of the present invention. It is understood that modifications and variations to the arrangements and details described herein will occur to those skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein. Reference list:

20 antenna

22 hollow radiator 24 electrical component

26 end faces

28 electric line

30 electrical resistance

32 resistance circuit

Claims

patent claims

1 . Antenna (20) with the following features: a first hollow radiator (22a) and a second hollow radiator (22b), which are each designed to emit and/or receive electromagnetic radiation, the first hollow radiator (22a) being sequential to the second hollow radiator (22b ) is arranged; an electrical component (24); an electrical line which is passed through the first and the second hollow radiator (22b) in order to contact the electrical component (24); wherein the electrical line (28) has a shield (28a) which is connected to the second hollow radiator (22b) by means of an electrical resistor (30).

2. Antenna (20) according to claim 1, wherein the first hollow radiator (22a) and/or the second hollow radiator (22b) comprises a helix antenna.

3. Antenna (20) according to one of the preceding claims, wherein the resistor (30) is arranged on an end face (26b) of the second hollow radiator, at which the electrical line (28) emerges from the second hollow radiator (22b).

4. Antenna (20) according to any one of the preceding claims, wherein the resistor (30) is a direct voltage resistor or an alternating voltage resistor, in particular a coil or a capacitor. The antenna (20) of any preceding claim, wherein the resistor (30) is part of a resistor circuit (32), the resistor (30) being a DC resistor, and wherein the resistor circuit (32) further comprises an AC resistor, the shield (28a ) is electrically connected to the hollow radiator (22) by means of the resistance circuit (32). An antenna (20) according to any one of the preceding claims, wherein the resistor (30) is part of a resistor network, the resistor network comprising a further resistor (30') arranged in parallel with the resistor (30). Antenna (20) according to one of the preceding claims, wherein the antenna has the absence of a crossover network, in particular a diplexer. Method for manufacturing an antenna (20) with the following steps:

providing a first hollow radiator (22a) and a second hollow radiator (22b), which are each designed to emit and/or receive electromagnetic radiation;

arranging the first and second hollow radiators sequentially;

providing an electrical component (24);

passing an electrical line (28) through the first hollow radiator (22a) and the second hollow radiator (22b); contacting the electrical component (24) with the electrical lead;

Connecting a shield (28a) of the electrical line (28) electrically to the second hollow radiator (22b) by means of an electrical resistor (30).

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