WO1986001340A1

WO1986001340A1 - Antenna construction

Info

Publication number: WO1986001340A1
Application number: PCT/AT1985/000026
Authority: WO
Inventors: Frank Buschbeck; Ronald Eisenwagner
Original assignee: Österreichisches Forschungszentrum Seibersdorf Gmb
Priority date: 1984-08-20
Filing date: 1985-08-19
Publication date: 1986-02-27
Also published as: EP0190291A1

Abstract

The antenna comprises antenna elements of which the axes are perpendicular to each other with common phase center and presenting a directive effect with two radiation diagrams electrically controllable, said elements forming a reception plane by their axis. The elements are each connected to a multiplier of which the output is connected to a summing circuit at the output of which the signal for the receiver may be received. In order to suppress interference signals, a third antenna element is used which has also a radiation diagram of which the axis is perpendicular to the axis of the other two elements and which also has the same base center. To this third element (C) there is associated, as for the other two elements (AB), a multiplier (14) providing the voltages (Uc) which are entered with the voltages (UAUB) provided by the other multipliers in the summing circuit (12). Thus, the amplification, respectively the attenuation and a plurality of the voltages provided by the three antenna elements (A, B, C) with each multiplier (14) may be adjusted as desired and particularly continuously and with a variable sign, with respect to each other.

Description

Antenna arrangement.

The invention relates to an antenna arrangement according to the preamble of claim 1.

For the positioning of directional antennas (eg frame antennas or ferrite antennas), mechanical, remotely controllable rotating devices are used in order to be able to specify the desired reception direction or reception characteristic, or the most favorable reception conditions (maximum reception signal or minimum interference) from the reception location ¬ radiation). Antenna arrangements are also known, the directional characteristic of which can be changed continuously in one plane or by changing over in the area 2τf. In order to avoid the problems associated with mechanical turning devices (icing, lightning protection, position feedback, costs), a directional antenna should be constructed in such a way that the directional characteristic is continuously pivoted in any direction, using only electrical methods, while the mechanical position remains unchanged. To hide the fields, e.g. In addition to the pivoting of the equivalent known antenna about a vertical axis, it is also necessary to adjust its inclination in the vicinity of sources of interference. The best signal-to-interference ratio can be achieved in some cases if known. Receiving antennas are positioned in such a way that the interference source lies exactly in the plane from which the antenna does not pick up anything, even if the greatest possible useful signal does not occur in this position. Antenna arrangements of the type mentioned at the outset are particularly affected by close interference sources which have components outside the reception level.

In order to avoid the problems mentioned and to optimize the antenna characteristic, according to the invention, in the case of an antenna arrangement of the type mentioned at the beginning, male of the characterizing part of claim 1 provided. Advantageous embodiments of the invention are given in the subclaims, the description and the drawing.

The invention is explained in more detail below with reference to the drawing. 1 shows a schematic antenna structure, the antenna elements A, B, C being formed by rings, for example loop antennas;

2 shows a section through an antenna frame;

3 shows a schematic diagram;

Fig. 4 is a circuit diagram for reception operation;

5 shows a diagram for explaining the voltage compensation;

6 shows an embodiment of a circuit diagram for reception mode;

Fig. 7 shows a basic circuit for the transmission mode and

Fig. 8 is a schematic explanation of the transmission mode.

The antenna arrangement according to the invention is particularly suitable for long and medium wave reception, but also for reception in the meter wave range.

1 shows three antenna elements A, B, C designed as loop antennas, which are preferably of the same size and are each perpendicular to one another with their axes. It is preferred if the three axes run through a common intersection point M or run essentially as close as possible to a common intersection point or have a common phase center. The loop antennas A, B, C are magnetically decoupled from each other by the arrangement perpendicular to each other and can therefore be regarded as independent units or systems. Instead of loop antennas, ferrite rods perpendicular to one another can also be used, or loop antennas and ferrite rods can be combined. In principle, all antenna elements can be used that have a suitable directional characteristic and can be set up on a common phase center.

For electrical decoupling of the individual antenna elements A, B, C, a capacitive shielding (foils, metal mesh or the like) can be provided.

Fig. 2 shows a section through an antenna element, the turns 1 of which are surrounded by mutually insulated wires by a shield 2, which may be connected to the receiver ground. An insulation layer 3 made of plastic, e.g. PVC, surrounds the shield 2. The outside of the antenna elements are covered with a covering 4 made of metal, e.g. AI, surrounded as lightning protection. In order not to disturb the magnetic field, the shield 2 or the sheath 4 are designed in such a way that they do not form closed turns, so that the formation of short-circuit turns is avoided. To this end, the shields can be interrupted or overlap if the insulation is mutual. The shield 2 or the casing 4 are not absolutely necessary.

The arrangement of the antenna elements with respect to the common center should be centrically symmetrical if possible. Deviations of the antenna elements from the common center should be as small as possible compared to the received wavelength damit so that the phase zero crossings are as possible take place simultaneously in the individual antenna elements.

Fig. 3 shows a schematic diagram illustrating how the magnetic component of the incoming signal H in the individual antenna elements A, B, C individual voltages

U, U and U induce which individual voltages to form the voltage X Y z fertilize the voltage U supplied to the receiver

S way to be linked.

4 shows a basic circuit for one of the antenna elements, for example a loop antenna or a ferrite rod, of an antenna arrangement according to the invention. A frame A is connected to a preamplifier 6 or impedance converter 6 or the like. An isolating transformer 5 for decoupling (FIG. 6) or preamplifier 6 are, however, not absolutely necessary. The preamplifier amplifies the individual voltage U of the frame A and the amplified voltage U is ^x 1 A connected to the input 9 of a controllable multiplier 14, preferably a 4-quadrant multiplier. If necessary, the preamplifier 6 is integrated in the multiplier 14. A control variable, for example a voltage, a digital control variable, or the like, is applied to the control input 15 of the multiplier 14, or the control takes place manually or mechanically. The output 11 of the multiplier 14 supplies a voltage U _f thereof

A value of the product of the input variable U with the tax

1: A large (which must be able to have both signs).

In particular, the multiplier 14 multiplies the input voltage by a factor such that the voltage U

A in particular steadily assume all values between the -1 to +1 times the voltage U present at the input 9

₁ A can. Depending on the desired value of the output voltage U

A the control size is changed or set, for which purpose an electronic adjusting device 16 can be provided, unless manual or mechanical actuation takes place. 6 shows as a multiplier an inversion device 8 with a voltage divider 10, for example a potentiometer. the inversion device 8 provides an output 7

Voltage value (-U) available, the amount

1A is the same as the voltage value (U) of the signal arriving from the preamplifier 6, but has the opposite sign, as a result of which the voltage zero crossings occur simultaneously at their inputs and outputs. The inversion device 8 can be an inverting amplifier, a transformer, a variometer or another known device for phase inversion. Between the input 9 of the inversion device 8, at which the amplified voltage U of the frame A is present, and the output 7, at which the never-inverse voltage -U

1 A is present, a variable voltage divider 10, e.g. a potentiometer, switched, at the tap 11 the

Output voltage U is removable, which between

A - and + U is continuously adjustable. This setting 1 A 1 A can be used with a potentiometer e.g. manually or using mechanical adjustment devices. The adjustment of the potentiometer 10 is equivalent to the change in the control variable of the multiplier 14. It is essential that voltages U at the output 11 of the controllable

A multipliers 14 can be made available which, depending on the desired direction of reception of the received signal between their maximum value and its inverse value, are in particular continuously controllable or adjustable.

The output 11 of the multiplier 14 is fed to a summing device 12, which also supplies the correspondingly set voltages U and U of the further antenna elements B and C, respectively, from circuits of the same structure and connected to the respective other antenna elements Bt are. C The voltages U, U and U are taking into account their signs summed and at the output 13 of the summing device 12, the voltage U arises as an antenna signal for the em

S recipient. At the same time, the voltage U can be

S large can be used for the actuating device 16, which in turn has three outputs 17 for the individual

Antenna elements A, B and C assigned multipliers 14 to maximize or optimize the received signal by adjusting the gain.

This arrangement ensures that the voltages U,, -

Ά ^u _ ö •, have no phase shift, ie. their zero crossings occur simultaneously. This is a necessary condition for the desired function.

F _(r (j _en reception operation there are two major types of reception:

1.) Setting to maximum reception signal and 2) Setting to minimum sensitivity from a certain direction, e.g. the direction of an interference signal to optimize the useful / interference signal ratio.

The procedure for receiving is as follows:

From the essentially symmetrical arrangement of the three antenna elements A, B, C around a common center ', it follows that the received wave in all three antenna elements voltages U, U, U, with the same

X Y 7

Phase position (simultaneous voltage zero crossings) generated. In order to achieve the two reception conditions mentioned above, the voltages are derived from the antenna elements A, B, C via the controllable multipliers 14 or the inversion devices 8 with the potentiometer 10, where, for example, voltages U can be generated by the

A full value of the amplified antenna signal (e.g. U)

1 A above zero to full inverse (180o phase-shifted)

Value (-U) can be set. It is noted in FIG. 1A that the output voltages U

A always have the same or inverse phase position as the signal voltages U present at input 9.

I Ά

1. Setting for maximum reception: In order to achieve a maximum reception signal, the multipliers 14 or voltage dividers (potentiometers 10) located in the individual circuits associated with the respective antenna elements A, B or C are each set in such a way (the potentiometers 10 are, for example, adjusted to their end positions) so that the individual voltages U, U, and U can be

A B C fen and the sum signal U of the individual voltages reaches its maximum value, in this case the multipliers do not weaken the incoming voltages; if necessary, they could even strengthen them.

This setting can be done manually, i.e. according to the volume of the receiver, by observation of measuring devices or automatically with electronic tracking or adjustment devices 16, e.g. by means of electronic regulation of the control variables of the multipliers. 16- denotes an adjusting device for setting or programming 16 for maximum reception or for minimum sensitivity from one direction.

2. Setting for minimal sensitivity from one direction:

Minimal sensitivity from a certain direction (interference suppression) is achieved by the output signals or voltages U of the multipliers 14

A or the voltage divider or potentiometer 10 each

Antenna element can be set so that the

Total voltage U of the jammer as close as possible

S zero volts is adjusted. In general, the signal to be received will not have its maximum possible value. If the interference signal is suppressed, the signal / interference ratio will nevertheless have a clear maximum. The effect of this procedure corresponds to the rotation of a frame antenna around two axes. Since the suppression of jammers is often local fields, the magnetic field of which is not horizontal, the adjustable "inclination" of the receiving axis is very important.

It is particularly advantageous that with the arrangement according to the invention, small signals can be made easily receivable without mechanical movement of the antennas, even if strong transmitters overlay the signal to be received or the signal from nearby directions

Signal is affected by reflections at the receiving location. After the interference signals, which can easily be compared with the amount of the useful signal, have been balanced, the desired signals can be amplified well, even if they are not received with maximum strength, since the interfering signals are eliminated. In particular, this plays a role in masking out local fields in which the direction of the incoming signals deviates from the horizontal.

In order to carry out an automatic setting of the desired reception characteristic, the actuating device can be designed so that it can be switched over between the two mentioned operating modes by 16 '. FIG. 5 explains the principle of interference suppression to simplify the explanation using two-dimensional diagrams. 5 are two mutually perpendicular

Antenna elements A, B (loop antennas) are shown. H

N represents the magnetic vector of the desired received signal, H the magnetic vector of a jammer. The Vek

St tor H induces the voltage U and in the frame A.

N NA in frame B the voltage U. The interference vector H induces

NB St in frame A the voltage U and in frame B the voltage

Traffic jam . These variables are projected onto the other frame in FIG. 5, since a magnet vector which is perpendicular to the frame or which is incident in the frame axis induces the greatest voltage.

A point U = is obtained from point 18 of frame A.

18A U + U; at point 18 of frame B one obtains U =

NA stA 18B

U + U NB StB

If the interference voltage U is to be rendered ineffective by an addition, a multiplier, e.g. the voltage U is reduced and inverted, so

StA that U = -U. This can be done by

StA StB-speaking setting of multiplier 14 of frame A

U to a gain factor k = - StB. j _{n in} this case are at the entrances of the ^stA

Summing unit 12 following voltages:

_stB

U

StB U

= - NA + U.

^U S „tA ^NB It can be seen from this that with this choice of k the interference signal no longer appears at the output of the summation device, but only an undisturbed signal pangsignal U.

It can be seen that complete interference compensation or balancing can only ever take place for a single interference signal; a residual signal remains from all other signals.

If several interference signals arrive, either one of these interference signals can be balanced by appropriate selection of the factors k or an improvement in the ratio of the received signal to all ^" somewhat attenuated interference signals can be achieved.

The three values of k can easily be set iteratively, e.g. in a corresponding iteration device, which can be part of the adjusting device 16, in order to use the individual voltages U, U and

18A 18B U to be able to combine the value O. 18C Is a potentiometer 10 in this summation

Middle position or if the manipulated variable is 0, the

Voltage value zero is tapped at the tap of this potentiometer 10 or multiplier or the voltage U

A is zero and the associated antenna element is not involved in the summation.

It is possible with an antenna arrangement according to the invention, with the provision of a plurality of receivers and evaluation circuits of the type described, each associated with them, to simultaneously receive transmissions coming from different directions on different frequencies and to suppress interference in order to ensure interference-free reception from different sources To get directions or frequencies. For example, at points 18, 18 ', any number of evaluation circuits 12, 14, 16 can be can be connected in time so that different directional characteristics can be generated simultaneously or different interference sources can be switched off for different signals to be received. It is obvious that with an antenna arrangement according to the invention, including an evaluation circuit, only one jamming transmitter can be masked out per receiving transmitter.

The shape of the antenna elements does not matter; these can be round or angular. However, they should be as similar as possible to one another. The antenna elements are preferably arranged in a mechanically fixed manner. It is essential that they have a directional characteristic with at least one zero point.

The antenna arrangement can be used for direction finding purposes, e.g. the signal to be found is balanced, since the factors k or the relationships underlying these voltages induced by a signal in the individual antenna elements allow conclusions to be drawn about the position of the signal direction or the straight line between the transmitter and Antenna arrangement can be pulled. In this case, the signals of the actuating device 16 are fed to a computer which calculates the position of the signal direction, or the ratios of the voltages or the factors of a display device are fed in and used further. With this antenna arrangement, however, only the position of the transmission line, but not the direction of the transmission, can be determined.

7 shows a basic circuit of an antenna arrangement according to the invention for the transmission mode. An HF - 1 ^* 2 -

The generator or transmitter 25 emits the transmission voltage, which is supplied to the individual antenna elements A, B, C already described via a voltage setting device 26. With the voltage adjusting devices 26, e.g. Vario¬ meters, multipliers, amplifiers or the like. The three antenna elements A, B, C can each be supplied with high-frequency currents of the same or inverse phase and with individually adjustable amplitude of the transmission current. From the addition of the fields of the three orthogonally aligned. Antenna elements result in a direction predetermined by vectorial addition for the radiation axis of the antenna arrangement. Due to the relative setting of the three transmission currents J, J j

A 'B, C in relation to one another in the direction and size, the magnetic axis of the antenna arrangement or the transmission vector U can thus be set in any direction in space. With the • voltage control devices 26, the individual values of the voltage or of the current relative to one another can be set between their -1 to + 1 times the value, in particular continuously as desired.

In FIG. 8, the radiation axis of the individual antenna elements is designated X, Y and Z and the antenna

A B C NEN elements A, B, C indicated.

In the antenna element A, the transmission current J supplied to the antenna element A generates a signal vector M, in the

"A tenneele ent B becomes a signal vector M from the transmission current J

B B and a signal vector M is generated in the antenna element C by the transmission current J_. These individual vectors thus add up to the transmit signal vector U, which changes in its spatial direction and size by changing the components M M, M in the desired manner.

A B C is changeable.

The respective voltage regulating devices 26 can be manually or electronically input with control units 27. be set to deliver the desired voltage or current values.

It is noted that the currents or voltages supplied to the individual antenna elements A, B and C should have the same or inverse phase position.

The antenna elements A, B, C shown in FIGS. 4 and 5 and in FIG. 7 can be the same antenna elements or can be assigned to the same antenna arrangement, but can also be different or further antenna elements, of which an arrangement for the Reception and one for sending. In the first case, the antenna elements can be connected or connected accordingly to the receiving or transmitting circuits (e.g. at points 19, 19 'or 18, 18' in Fig. 4).

For radio communication with a distant partner via ground and / or spatial waves, it is advantageous if the incoming signal is first set to maximum reception strength for the transmitter to be answered by correspondingly setting the amplification factors k ^, k ₂ , k, of the multipliers . The gain factors (kk,) set or required for this purpose are supplied to the voltage setting devices 26 of the transmission circuit by detection units or storage units (for example in the actuating device 16). In this way, the currently optimal response transmission path can be found and the transmission antenna can be controlled accordingly. If the suppression of a jamming transmitter is necessary for the optimization of the reception, only the setting of the transmission characteristics for the reply transmission for the incoming signal can optimize the reception, ie the ratio of the useful signal to the jamming signal can be minimized, so that both optimal reception and maximum transmission mode can also be achieved. It is noted that the transmission circuit (FIG. 7) with the antenna elements is also seen as an invention.

Claims

Claims:

1. Antenna arrangement with an electrically controllable directivity with two directional characteristics, with their axes perpendicular to one another, antenna elements with a common phase center, such as Frames, ferrite rods or the like, which define with their axes a reception plane, which antenna elements are each connected to a multiplier, in particular a controlled amplifier, the outputs of the two multipliers being connected to a summation device, at the output of which the signal for the receiver can be removed, characterized in that for masking signals, for example Interference signals with components outside the reception level, e.g. Fields of local interference sources, a third antenna element, also having a directional characteristic, e.g. Frame, ferrite rod or the like. Is provided, which is perpendicular with its axis to the axes of the other two antenna elements and the same

Phase center has that the third receiving element (C) as well as the two other antenna elements (A, B) is assigned a multiplier (14), in particular a controlled amplifier, from which voltage values (U_) can be tapped together with the voltage values (U U_.) of the two other multipliers are fed to the summing device (12), and that the amplification or attenuation and the polarity of those supplied by all three antenna elements (A, B, C). Voltages (U, U U) with the respective multipliers (14) can be set arbitrarily in relation to one another, in particular continuously and with a variable sign.

2. Arrangement according to claim 1, characterized in that the signals supplied by the antenna elements (A, B, C)

(UU U_) in these can be multiplied by factors (k ₁ , k ₂ , k_) between -1 and +1.

3. Arrangement according to claim 1 or 2, characterized in that the signals supplied by the antenna elements (A, B, C) (ü _v X, U _v Y, UZ_) each have a preamplifier (6) connected upstream of the respective multipliers (14). for the preamplification, in particular in each case of the same size.

4. Arrangement according to one of claims 1-3, characterized in that the multipliers (14) with actuating or Steuereinrichtun¬ gene (16) for optimizing the ratio of the desired received signal (U _M ) and simultaneously incident Störsig¬ signal (third-party transmitter ) can be controlled in the signal (U_) emitted by the summation device (12).

5. Arrangement according to one of claims 1-4, characterized in that in order to maximize the desired received signal (ü) the respective multipliers (14) with actuating or control devices. (16) can be set to a maximum value.

6. Arrangement according to one of claims 1-5, characterized in that in the presence of only one directed interference signal in the reception spectrum, the interference component in the output signal (U _ς ) of the summation device (12) by means of the adjustable multiplicators (14) brought to zero or is balanced.

7. Arrangement according to one of claims 1-6, characterized in that the multipliers (14) are formed from amplifiers with adjustable amplification ratio and adjustable transmission polarity.

8. Arrangement according to one of claims 1-7, characterized in that the multipliers are 4-quadrant multipliers.

9. Arrangement according to one of claims 1-7, characterized in that as a multiplier (14) an inversion device (8), e.g. an inverting amplifier is provided with which one of the voltage supplied by an antenna element

⁽ U ₁ -, U _1B , U ₁ ⁾ corresponding inverse voltage ^(_u ι _A '~ ^U _I B' ~ ^U 1C can be generated, an adjustable voltage divider (10), for example a potentiometer, being connected in parallel to the inversion device (8) at which the selected voltage value (U _A , U _B , U _C ) can be tapped.

10. Arrangement according to one of claims 1-9, characterized in that the multipliers (14) is assigned a common actuating or control device (16), for example .. a manually or electronically actuated control regulator.

11. Arrangement according to one of claims 1-10, characterized in that the output signal (U_) of the summation device (12) of the actuating or Steuereinrichtunq (16) for the Multiplikato¬ ren (14) is supplied.

12. Arrangement according to one of claims 1-11, characterized in that, for example for direction finding purposes to determine the position or orientation of a straight line through the transmitter and the antenna arrangement or the like., A display or detection device and / or if appropriate, a storage unit is provided for the values of the respective amplification or for the amplification factors (k ₁ , k ₂ , k_) or for the inversion of the individual multipliers (14), and / or that the amplification values or the amplification factors of the individual multipliers of a computing unit are supplied in particular for evaluation.

13. Arrangement according to one of claims 1-12, characterized in that the antennas having a common phase center: -, elements (A, B, C) are constructed essentially centrally symmetrically.

14. Arrangement according to one of claims 1-13, characterized in that in order to take advantage of the respective instantaneous optimal transmission path, the values of the respective amplification or the amplification factors (k ^ k-. -) determined for maximum reception each have a controllable voltage adjusting device ( 26) are fed to an antenna element (A, B, C) or controllable voltage adjusting devices (26) are fed to a separate arrangement of three further antenna elements of the same structure.

15. Arrangement in particular according to one of claims 1-14, characterized in that with the adjustable voltage control devices (26), the antenna elements (A, B, C) of the transmitter depending on the desired direction of the signal to be transmitted

Transmitting high-frequency current (J A-, J_ Ώ., J_) can be supplied, which has the same or inverse phase and individually adjusted amplitude to the phase of the transmission signal (U) to be emitted.

16. The arrangement according to claim 14 or 15, characterized in that the voltage adjusting devices (26) are formed by variometers, multiplicators or amplifiers.

17. Arrangement according to one of claims 1 to 16, characterized in that the voltage adjusting devices (26) are assigned electrically or manually operated control units (27) or the values for the respective amplification or the amplification factor from the detection device or storage unit gates (k ^ k- ^ k- or are fed for inversion.

18. Arrangement according to one of claims 1 to 17, characterized in that the antenna elements (A, B, C) can optionally be connected to the multipliers (14) or the voltage adjusting devices (26).