DE2235958A1 - ANTENNA SYSTEM - Google Patents

Description

PATENT AGENCY OFFICE

HOMSEN - TlEDtKB B ^ÜHLmC U * i * cnco

TEL. (OS11) 53 M11 TELEX; 5-24303 lopat 2235958

M11

F ⁴ ATE N Χ AN WALTE

Munich: Frtnkiurt / M .: Dlpl.-Chem. Dr. D. Thomsen Dlpi.-Ing. W. Welnkeuff

Dlpl.-Ing. H. Tledtke (Fuchihohl 71) Dipl.-Chern. Q ₁ Bühllng

Dipi.-iiiä. B. Chins ;; -. "■:; Dlpl.-Chem. Dr. U, Eggers

8,000 Munich 2

Kal «er-Ludwlg-Platz 6 ^ ¹

Matshüshita Eleotric Industrial Co. Ltd. Osaka _t Japan

Antenna system

The invention relates to antennas use a magnetic core,

With the invention, an antenna system is gesehaffen "the besitiat a magnetic core, which is provided with threaded disgusted him Bpuiieh - _t to time changes of Rernpermeäfeilität and changes in the inductances of the on the i & eim

κ »Antenna coil and output coil to cause Äür parametrl *

«Ö see amplification of the received signal» to thereby elfiö ver » ^ get stronger antenna output power *

The invention also provides an antenna system with a permanent magnet en seöehaffen, duren den

MOndilcii » Abrwtün, Intbctöftdtt * by T« l »fon, b * may * n schrlflllch * r BeWIllgang Po« t «(*» dt (Munich) Kto 11M74 Or »tdn« r 'BiinK (M0n * »n) Klo. 8! Β470Ι

Equal bias of the core is easily obtained.

The invention also provides a series antenna which is composed of a number of the above-mentioned antenna systems which are used as antenna elements and their directional characteristics can be controlled as required by adjusting the amplitude and phase of the parametric pump sources for the individual antenna elements.

The invention is illustrated below with reference to schematiecher Drawings of exemplary embodiments explained in more detail *

Pig * 1 shows a known antenna system with a magnetic core;

Figure 2 shows a graph of inductances and mutual inductances versus one Gleichetrom in the known antenna system according to Fig. 1;

3 shows an equivalent circuit for an embodiment of the Antenneney et one according to the invention;

Figure ¹ · I shows a perspective view of the Structures of the antenna system according to the invention;

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Pig. 5 shows a magnetic field in the magnetic core of the antenna system according to FIG. 4 by a current flowing in a pump coil is set;

Pig, Fig. 6 is a perspective view of an experimental arrangement showing the connection of a signal source and a load to the antenna system of Fig. 1 ;

FIG. 7 shows in a graphic representation that obtained with the arrangement according to FIG Power transmission gain, which is plotted against the internal resistance R, where the Load resistance R, used as a parameter;

8 to 11 show perspective views of other embodiments of the invention Antenna system;

Fig. 12 is a perspective view of the embodiment ¹ provided with coils of FIG. 8;

Figure 13 is a perspective view of the spooled embodiment of Figure 10; and

Fig. ΙΊ shows a pictorial representation of an invented 209885/1249

improper row pantpnne.

gin known antenna system with $ l $ p $ Magjjfjtkejin shown in Fig. 1, wherein the reference number I pin ^ n. ' kern btaeiehnet, made up of two separate)} ^

which are provided with an antenna coil 2 wound on it jDijB bjB |. <| e ^ Kprn ^ bsciinitte 1 pind but eirjei? Iphnitt 3 coupled together, to which an output coil | f | .ckgl | t | (5jb. In connection with the i

a wiiffcerer grain 5 provided. #uf deip

(6 wrapped, per through the 3jbr, opi | de_ρ ^{1 your Ke} ^ 5 ^^

^the J _f ^ j

djen bp | .d ^ Teilpn der Anfcenn ^ nspulje? ierftr.j? | Ck || p.

ff | f. ? The Induk | biyi | b ^ tfn JLa if ^ d ^ i of the / Ap-2 and the output coil k and dip Qegeij | L | riduk | ti ^ | between these coils; These inductances are over the values of one in the pulse coil 6 f | .ie ^ endfij

^ fie from Fig. 2

# «'FP ^ tWfcät La der Ant ^ n ^ pspufe 2 Ι || β mifijC ^ strpine hardly, while dfe Iijduk | biyi ^ t il and the Oegeninduktiyität M merkb'ar' gij) ß ^ e? .Lung of the qieichstroms on 'ein'e'n fef, chung each optimal
ep, uJe t unij of the output coil ^: ^ l the fr ^ uity of the pumping current can be changed ^ §ßv der

INSPECTED

In the known antenna system according to Pig. I will the mutual inductance between the antenna coil 2 and the outputBBpule Ί changed in the pump frequency, resulting in parametric amplification of a signal received by the antenna and achieving an amplified antenna output signal leads.

The change in the mutual inductance is attributable to changes in the permeability of the magnetic core 3. Accordingly it is necessary to obtain large changes in mutual inductance with small pumping current, one compared to the Reluctance (magnetic resistance) of the core 1 to choose sufficiently high reluctance of the core 3 to saturate during operation of the core. In the above structure in which the core 1 is divided into two separate sections, the Antenna efficiency, however, very low; Likewise, with such an arrangement of the cores 1 and 5 as shown in Fig. 1 requires a considerably large pump power and direct current power to activate these cores 1 and 5. Furthermore is the leakage flow is considerably large.

With ,, the invention are the aforementioned Disadvantages inherent in the conventional antenna system due to improvements in the core structure and the winding process of the coils is eliminated, so that the gain is extremely increased.

The efficiency of the conventional antenna system 209885/1249

lit low «because ea mainly uses the common inductance between the antenna coil and the output coil, which changes depending on the pumping current causing saturation of the magnetic core, and since it uses a magnetic core divided into two sections. According to the invention, the magnetic core and the coils are constructed and arranged in such a way that changes in the permeability of the core itself can be caused over time and, on the basis of this change, the external inductance between the antenna coil and the output coil is made variable in order to achieve a high degree of amplification. Likewise, the turns of the pump coil are arranged perpendicular to the turns of the other coil, ■ o that coupling between the antenna coil circuit and the output coil circuit is formed solely by the mutually variable inductance, which eliminates the otherwise possible deterioration in efficiency.

The principles of operation of the present invention are discussed first in connection with Pig. 3 explains where an equivalent circuit is shown for the antenna system according to the invention. In Fig. 3, L (t) represents an equivalent inductance, the changes in the inductances of the antenna coil and the output coil as a result of changes in permeability over time of the magnetic core taken into account. The circle on the left of the inductance L (t) (hereinafter referred to as the signal circle) consists of an antenna coil tuning reactance X ^. Here, V ”and FT represent those induced on the antenna coil Connection voltage or the resistance at the antennas * -

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BpulenanechlÜBsen at fles onanz. The circle, on Je _; r ^ r.echjkei *. Side of the inductance Lit) (hereinafter referred to as. Ausipnpkpelf.) 'Consists of an output coil, nabst4ijmjj? Eaktaij55 3U and a load H ,, .- In this ^ uiv ^ lenzgschaltung Egpj? Äf§tiert the loss resistance . Coils and the core · The quality factor Q of the circle traced above on the? iinkeri side of L (t), ie · of the ^ signal circle ^ es> large. Incidentally, this circle is not directly coupled to any circuit element, but rather d ^ r, ci | the pbjen called ^ inductivity

..The inductance LCt) ₁ which deals with. a change in angular freedom ω is generally given jni £

L (t) s L _Q + 2L ^ cosp t

Does a signal _{stream i ß} (t_) fly with a iiii <| uen? «K _b un4 a driver overcurrent i _p (jb) ΐη% of a frequency> M in the inductance
from L (t) au / stepped

V (t) »

By putting:

ORIGINAL INSPECTED

Using equations (2) and (3), the following relationships between voltages and currents can be obtained:

Ί ~

where the complex conjugate number to », = ^ * ^w e represents.

P 8

i «and W ₃

If the tuning reactances X- = -

and

g .J ₂ C ₂ ) of the signal and output circuits according to Fig. 3 are set in such a way that these circuits _{are matched to the Wirikeifrerechneri u> e} or ^ ₂ , the relationships between the voltages and currents in these circuits result from the equation ( ¹ O:

^R s -

Then, using equation (5), the power transfer _gain G t2 at resonance

and

) Are obtained with:

t2

s «Ta« TI

(6)

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ORIGINAL fNSPECTED

where <χ * 'and R, - and Rm ₁ total series resistances

¹ W ^R T1
of the signal or output circuit. The negative sign of the denominator in equation (6) means that a negative input resistance can be formed by the inductance that changes over time and that oscillations are also possible. Equation (6) gives the condition for the oscillation with:.

d ₌ - _s ι (7)

^R Ta ' ^R Tl

If the output circuit is tuned to ^, the power transfer gain G., can be obtained in the same way with:

^R a ^R
In this case the maximum gain is ^ / ^lv>

Fig. Ι shows an example of the structure of the antenna system, the operation of which is based on the above-mentioned principles. In FIG. K , the reference number 7 denotes a magnetic core which has two spaced apart openings or passages 8 and 8. The reference number 9 denotes an antenna coil which is partially wound around the entire body of the core 7 and in which some of its turns 10 run through the openings 8 and 8. Reference numeral 11 denotes an output coil which is wound so that

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all of its turns run through the openings θ and 8 *. The reference number 12 denotes a pump coil which is wound on the part of the core between the openings 8 and 8 ¹ so that its winding is perpendicular to the winding of the antenna and the output coils 9 and 11, respectively.

Pig. Figure 5 shows this by the current in the pump coil 12 in the core 7 of the construction described above generated magnetic field. Since parts of the core 7 are magnetized around the openings 8 and 8 *, the permeability of these parts is changed. Thus, the inductances of the change The antenna coil 9 and the output coil 11, which are wound on the core parts around the openings 8 and 8 ', at the pump frequency. The core 7 should have at least two openings, such as the openings 8 and 8 'described above.

Whether the antenna system according to Pig. ¹ I actually works according to the principles described above, was investigated with an experimental circuit shown in FIG. In this circuit, the magnetic core and the type of winding of the individual coils are the same as for the structure according to FIG. 4, so that they will not be described further. A signal source 13 with a frequency of 1 MHz and an internal resistance R is connected between the connections of the antenna coil 9. To the output coil 11 is a

Load resistor FL connected in series with a tuning capacitor C ₂ .

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The experimental circuit described above was operated under parametrisehern pumps at a pumping frequency of H MHz for measuring the Leistungstibertragungsverstär- effect for an output frequency of ^ O ^ = 3 MHz. The power transmission _{gain G ^ 2} results in this case from equation (6):

t2

12th

5,

Fig; 7 shows the results of measurements of the power transmission gain Gijji plotted against the internal resistance H- using the load resistance R ^ as a parameter. w "ie from Fig refer 7 is \ is -. be seen as a result of the negative resistance - the gain, the greater my the internal resistance R" is the vibration is sfeatt at a certain internal resistance value The following table provides values of the internal resistance Rg at.. , at which the oscillation starts for certain values of the load resistance R ^:

Load resistance Ri in ohms

Internal resistance, R ^ in ohms for the onset of ^{g of} the oscillation

0 IO 20

5.5

2.5

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From the table above and from equation (7) the oscillation condition, the values of ^u _e ^{U /} p ^L l ^and the equivalent resistance R_ for the loss are determined with:

and R- ^s 15 (ohms).

Dashed curves in Fig. 7 represent results of calculating the line transmission gain Q _fc2 from the above values and using equation (9). It can be seen that the measured values shown by the solid curves agree well with the calculated values, and this takes good account of the fact that the embodiment of the antenna system according to the invention described above operates in accordance with the principles set out above.

Thus, in the antenna system according to the invention, the antenna coil and the output coil provide the function of time-varying inductance, and through this function can parametric amplification of the received signal for obtaining an amplified antenna output signal.

Since a completely closed magnetic loop is formed, the leakage flux is also very small, and the Feed power and DC power are reduced.

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Eb other embodiments are now described, use the permanent magnets for the (magnetic) preload.

In the embodiments of Figs. 8 and 9 are Permanent magnets provided in close contact with the magnetic core, which is the same as the magnetic core 7 of FIG. In the embodiments according to FIGS. 10 and 11, permanent magnets are used provided at a distance from the magnetic core 7.

In the embodiment of FIG. 8, two permanent magnets 50 are fixed in close contact on opposite sides of a portion of the core between openings 8 and 8 ^1.

Fig. 12 shows the core 7 of FIG. 8, which with individual Coils is provided.

In the embodiment of Figure 9, permanent magnets are attached in close contact on opposite sides of portions of the core on both the upper and lower sides of each opening 8 and 8 '. The coils are wound in the same way as in the embodiment of FIG. The pump coil 12 is wound onto part of the core between the openings 8 and 8 ¹ . The output coil 11 is wound in such a way that all of its turns run through the openings and hit the permanent magnets.

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wraps are attached to core sections on one side of each opening θ and 8 · are attached.

In the construction of the embodiment according to FIG. 8 or Fig · 9ι in which the permanent magnets 50 or 51 in close proximity Contact attached to the core 7, the coils are partially wound on the permanent magnets. This is acceptable though the permanent magnets 50 or 51 have a sufficiently high resistance

a value, for example about 10 ohm-cm, as at Ferrite magnets. However, for low resistance metal magnets, winding the coils onto the magnets will result to undesirable large core losses.

The embodiment of Fig. 10 uses channel-shaped magnets 53 on opposite sides of the core 7 are attached with their legs 52 formed from a non-magnetic material in close contact with the core. With With this structure, it is possible to change the bias field formed by the permanent magnets 53 in the core 7 the strength of the non-magnetic material. In this embodiment, the pump coil 12 is immediately on wound the core portion between the openings 8 and 8 * on the inside of each permanent magnet 53. In this case For example, either metal magnets or ferrite magnets can be used as permanent magnets 53.

The embodiment of Fig. 11 is also used channel-shaped permanent magnets 5Ί on the inside of a

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~ ¹⁵ ~ 2235SSa

Have a recess a non-magnetic material 55. These magnets 5k Bind are placed on the top and bottom edges of the core 7. In this case, it is of course possible to change the bias field generated by the permanent magnets 5 * 1 in the core by changing the thickness of the non-magnetic material layer 55. In this embodiment, the coils are wound in the same way as in the previous embodiments.

In the above-described embodiments of FIGS. 8 to 13 * in which the bias field is generated by the permanent magnets in the core, no bias source is required, so that the associated circuit structure can be simplified. Likewise, there is no possibility of causing displacements from the resonance due to fluctuations in the bias voltage source, so that steady operation can be ensured. Furthermore , the adjustment of the bias field generated by the permanent magnets in the core can easily be carried out »

The antenna system Jc described with reference to FIG. H can be used as an antenna element for series antennas. Sol before row antennas can bring about advantages over the known row antennas.

In the known series antennas, phase shifters and Attenuators either between the associated row element lind the transmitter or between the row element and

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when the receivers are switched on, switched on in a suitable manner or a lumped constant or distributed constant circuit is provided.

Such phase shifters or attenuators or circuits with lumped or distributed constants are adjusted either electrically or mechanically to achieve the desired directional characteristics of the row antenna create.

These phase shifters and attenuators or circuits with lumped or distributed constants may only cause minor energy losses through their insertion. With the commonly used ferrite phase sliders and diode phase shifters, however, result in energy losses from 1 to 2 dB. Furthermore, with a single phase shifter, the variable phase range is limited, and where broader Phase ranges are to be detected, it is necessary to use different phase shift units in combination, which is inevitably accompanied by an increase in energy losses. Therefore, the number of phase shifters inserted in combination is limited by the increase in energy loss.

Furthermore, in the case of inserted circuits with lumped or distributed constants, the amplitude and Phase of the current in the antenna elements can not be changed independently, so that the setting of the directional characteristics disadvantageously encounters extreme difficulties.

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Pig. 1 * \ shows a series antenna according to the invention. This row antenna consists of two row elements 101 and 102, each of which is the antenna system according to FIG.

In each of these elements, the permeability of the magnetic core 7 is changed by the pump current i = I_cos ( ¹ V t + θ) flowing in the pump coil 12 at the pump frequency *. This change causes changes in the inductances of the antenna coil 9 and the output coil 11 at the pumping frequency. In other words, the antenna coil 9 and the output coil function as a variable inductance element. This variable inductance L (t) is given by:

L (t) = L ₀ + 2L ₁ COS (tot + θ)

Power is transmitted through this variable inductance L (t) between the signal received by the element and the pump signal, d. H. the received signal will subjected to parametric amplification. Thus, a strong antenna output signal from the output coil 11 can be obtained. If it is now assumed that a received signal

Jc t
If current I_e flows in the aforementioned element with variable inductance L (t), the voltage e generated in the element with variable inductance is:

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e *

-j (o ₊ to) t + θ ^{P 8}

-j (o ₊ to) t + θ -j -j (« _p - ^ ₈ ) L ₁ C ^{P 8 P} J · I ₈ (10)

Furthermore, the output voltages e ^ p and e _down nmung of the output
given as follows:

when coordinating the output circuit to ip + u> _) or (UX -u>)

P S ρ Β

j (^ _n +) t + θ _η

^e up ^s J «" p * " _e ) -V ^PP · I ₈ - .. («)

j (^ _n - ⁰ Jt + θ ^and «down ³ -J ^ p.- ^w a>^# H ^e ' ¹ S - · ⁽¹²⁾

The coefficient L ^, in the above variable inductance depends on the material and structure of the magnetic core and the coil construction and is proportional to the amplitude of the pumping current. Thus, the amplitude and phase of the antenna output signal can be controlled by changing the amplitude and phase of the pump current.

If the output circle is matched to (w + ^{4 O, are}

ρ s

the antenna output signals _{e UD} and e _{UD of} the row antenna elements 101 and 102 are given as follows:

^e u _P

1. (13)

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and e ⁽²⁾ () ^{(2) P 8}

_{+ θ} (2) ₊ 4 cos

^{p 2}

i _R

.D

where k * 2Τά / Λ and "A is the wavelength. When these two output voltages are combined, the resulting voltage e is given as follows:

Jiw _D + ω) t
+ ta _s ) e ^v

The directional characteristics D (v) of the row antenna are likewise given as follows:

The sizes L ₁ * ¹ ^ and L ^ ² ^ for the antenna elements

101 and 102 are each the amplitude of the parametric pump

(1) The currents in these elements 101 and 102 are proportional, θ 'and θ ^v ' are identical to the phases of the parametric pump sources of antenna elements 101 and 102, respectively the desired

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th directional characteristics obtained. The directional characteristics are the same controllable by changing the amplitude and phase of the parametric pump source.

Because the antenna elements above provide high gain and because they are directly connected to the transmitter or receiver are coupled »is it possible» a row of antennas with obtain extremely high efficiency. Such a highly effective array of antennas can of course be constructed in the same way using the antenna elements according to FIGS be.

As stated above, with the invention it is possible to provide a highly efficient series antenna which can provide an amplified antenna output signal. A DC bias voltage can also be used with the invention (of the magnetic field) can be easily obtained.

With the invention, an antenna system is thus created that uses a magnetic core that is on it wound coils is provided so that changes in the permeability of the core itself over time are shown. With the Changes in the core permeability over time are the inductances of the antenna coil wound on the core and Output coil for parametric amplification of the received signal changed to obtain an amplified antenna output signal. Likewise, by using a number

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such antenna systems a series antenna, with desired and controllable directional characteristics.

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Claims (4)

Claims 1. Antenna system, characterized by a magnetic core (7) for receiving electromagnetic waves, the one Number of openings (8, 8 '), a first coil (12) serving as a pump coil for changing the permeability of the magnetic core (7) »with this first coil (12) on one part of the core (7) is wound between adjacent openings (8, 8 '), and two second coils (9 * H) * through the are connected by the pumping coil (12) generated magnetic flux and are wound such that its winding is perpendicular to the winding of the first coil (12), one (11) of this second coil (9 * H) is wound onto the core (7) in such a way that all of its turns pass through the openings (8, 8 ') run, while the other (9) of these second coils (9 * H) is wound with some of its turns around the entire body of the core (7) and with its remaining turns through the openings (8, 8 ¹ ) is performed. 2. Antenna system according to claim 1, characterized by at least one permanent magnet (50 »51» 53 »5Ό, the one for generating a bias field in the core (7) is attached to this. 3. Antenna system according to claim 2, characterized by non-magnetic spacers (52, 55) which are provided individually between the permanent magnets (53 »5Ό and the core (7) and the intensity of the through the 209885/1249 Magnet in the magnetic core (7) set bias field make changeable. 4. Use of an antenna system according to one of the preceding claims in a series antenna, wherein with the first coil (12) a device is connected ι which independently the amplitude and phase of a through the first coil (12) controls flowing pump current and thereby the directional characteristics of the row antenna can be maintained as desired and controllable. 209885/1249