DE102011016083A1 - Method for transmitting modulated radio frequency (RF) signals from transmitting station through RF-proof wall to receiving station, involves transforming data signals into waveform to overcome wall by overlay/Heterodyn transponder - Google Patents

Abstract

The data signals generated by transmitting station (100) are received by a first overlay or Heterodyn transponder (109) on one side of the wall (114). The signals are transformed to waveform to overcome RF-proof wall. The transformed waveform is transmitted to second overlay or Heterodyn transponder (105) on other side of the wall through the wall. The waveform is transformed into data signals with respect to corresponding receiving station (103). The data signals are transmitted to respective receiving station.

Description

The invention relates to methods of transmitting modulated electromagnetic fields over RF-dense walls. In this context, the invention also relates to methods to introduce modulated electromagnetic fields from the outside into a closed container and to be effective in the interior, even if these containers represent a metal-tight housing and thus a Faraday cage.

It is known from physics that a housing made of conductive material creates a field-free space in the interior of the room, because from the outside on the shielding shell passing electric fields are derived through the outer shell of the cage and magnetic field components are eliminated by eddy current formation, so that inside the cage forms a practically field-free space.

This also applies to almost all high-frequency electromagnetic fields and thus also to RF fields that are suitable for reading out an RFID transponder. A directed from the outside of a reader on a closed housing of conductive material RF field is therefore not able to get into the interior. Transponders that are located in a metal container and thus in such a Faraday cage can therefore not be recognized and read directly from outside.

To such Faraday cages, the interior of the passenger compartment of a motor vehicle, the interior of containers of various sizes (eg trolleys in an aircraft for storing food and drinks, large train, load and overseas containers, etc.) and of various shapes and forms Material (aluminum, steel, etc.) and much more can be counted. Even with conductive coated packaging material or films such field-free areas can arise almost instantaneously.

All such conductive, especially metallic housings (eg gearbox housings, engine housings, tanks, rooms in reinforced concrete structures, film packaging, etc.) exhibit these properties and are summarized below together under the term "container". The HF-dense interfaces to be considered are not limited to containers; a related limitation of the invention is thus not available. The application of the invention is possible in a wide environment. From a certain size, containers of very large dimensions represent only an HF-dense barrier which, viewed as such, must be regarded as a container with an infinite extent.

In general, it is not impossible to bring a high-frequency signal over an RF-dense barrier, eg. B. when the high-frequency signal is conducted by cable to the other side of the barrier and there (additionally processed or not) via a coil or an antenna used to build an electromagnetic field and / or emitted.

However, it is not always possible to provide such a cable guide; Also, it is not useful in all cases to provide this, z. If, for example, there are large pressure differences, gas permeability at break-through points (eg in potentially explosive atmospheres or corrosive environments) could be dangerous if tampering attempts should be ruled out, etc.

Transponders that are used to label products and objects are in the context of so-called Auto-ID, RFID applications or access systems u. a. are known and represent in the context to be seen radio partners of reading stations, which are often separated by such barriers. In this case, active, semi-active or passive transponders are firmly connected to a product or object to be identified. By means of a reader which generates an electromagnetic field and both supplies the transponder with energy and transmits data to it with this field, such a transponder can be recognized, read its data content and, via this detour z. B. the object can be identified as such.

Other, more extensive applications are possible with such a technology.

In the state of the art, the presence of the transponder, switching states and even analog values of a reader unit can be transmitted by means of a transponder, each transponder (individually viewed) standing for only one possible function (an object, a switch, an analog value, a sensor value, etc.). If more than one function is to be included in a system, then you need i. a. also several transponders and possibly more than just a reader. The use of these marking and transmission techniques should be possible with the technique according to the invention as far as possible across barriers, which attenuate HF very strongly.

The numerous existing and necessary compromises for these techniques are not solved by this invention, but are affected. This applies both to the frequency selection and the determination of the transmission energy.

It should also be noted that using transponders in the context of RFID concepts realized applications can be designed with different goals that need to be considered.

Methods are known from the prior art, with which wireless switching functions are realized in that a reading station detects the presence of a transponder and switches the function of a system or device recognizing an acceptable transponder, or this task to the control of a technical unit then directs, so that then controls the respectively to be switched or operated target function.

In these techniques, the presence of a (valid) transponder securely detected by the reading station triggers the actual switching function via the reading unit. Here it should be decided whether a valid for switching functions transponder such switching functions may also trigger outward on the container wall away or not.

However, this is assigned to the switch problem and therefore does not affect the technique to be seen here in the foreground.

Techniques are further known from the prior art, with which switching functions can be transmitted wirelessly by z. B. a reading station, the state of a transponder, which can be activated or deactivated by a switching function, interrogates and switches the so-called switching state according to the function of a system or device, or this task to the control of a technical unit forwards, so that then serves the respective target function to be switched or operated.

In these techniques triggered by means of switching function activated or deactivated, thereby u. U. also permanently located in the detection field of a reading station transponder from the actual switching function, which is also mediated in this context via the reading unit. This is also assigned to the switch problem and therefore does not affect the technique to be seen here in the foreground, ie. H. The planned switching strategy should not be affected.

Techniques are also known from the prior art, by means of which sensor elements, which can have an influence on the properties of a transponder (for example on the antenna adaptation, on the backscatter frequency or on the frequency of the local oscillator), can convey analog data. If the transponder is queried by a reading station, then it can win and forward a response proportional to the analog or sensor value.

Thus, in the prior art, the presence of transponders, switching states and also analog values can be detected wirelessly by means of a transponder application and made accessible to a reading unit, each transponder (individually viewed) standing for only one (and only one) possible function (a switch , an analog value, a sensor value, etc.). If more than one function is needed in a system, then you need i. a. also several transponders and possibly more than just one reader.

The techniques according to the invention should make it possible to use the transponder unrestrictedly over the container walls or barrier, but nevertheless exert an influence.

So i. a. limited the range of RFID techniques. The inventive technique increases u. For example, the range of "normal" RFID technology may be because the behavior of the wall penetration assembly may be considered as an amplifier. Thus, transponders that are located on the other side of a wall of a reading station u. U. still be reached from a distance from which otherwise a communication would not be possible. This can have an advantageous effect, but it can also prove to be a disadvantage.

Another limitation arises from the choice of frequency. Transponder and reader frequency must i. a. be coordinated and match each other. The fields of application are quite different. Namely, the higher the frequency can be selected in a normal RFID application, the greater (with comparable energy use) the action radius can be configured per se. The wall penetration works only on defined frequencies, whereby input and output frequency are not necessarily the same, but can be the same. The wall transfer must therefore be tailored to the respective operating frequencies, but this is self-evident.

At a very high frequency, it is practically impossible to use transponders in problematic environments (metal, liquids, etc.). However, transponders that operate at relatively low frequencies (eg 125 kHz and smaller) can also be used in problematic environments. Both transponder types can coexist in a large container. However, the smaller the frequency behind a wall, the greater the need to generate the generated fields, which are normally generated by high energy reserve readers for powering and reaching the transponder. Here, the same thing would have to be generated by a component of the arrangement according to the invention located on the back of the wall, but this is generally not possible. Thus, transponders at a given distance behind the wall, which could normally still be reached by a reading station in front of the wall, u. U. not reached anymore. This can prove to be a disadvantage to consider.

This leaves the problem that in a given environment electromagnetic fields, the u. U. are designed and used only for low frequencies, can overcome an even smaller spatial distance, while electromagnetic fields with high frequencies that are better suited for longer distances, u. U. even further.

In this environment, and taking into account the various application goals when using transponders, the invention solves the problem of a modulated RF signal emitted by a reading device for the purpose of transponder identification (of transponders that are behind a wall) directed to the RF wall is directed to the other side without wall opening. The RF signal, without altering its essential characteristics, is passed through the wall and behind the wall to effect as if the reading station is behind the wall. In addition, data is to be received from the transponders located there, to be routed back via the wall and sent there as a normal transponder response signal to the reading device.

Thus, the invention also solves the problem of guiding a modulated signal for the purpose of content detection in the interior of a container to take effect inside to take in the interior of the container data from the transponder located there, this on the container wall to the outside conduct and in turn there to transmit as a normal transponder response signal of the reading device.

The reader should not even notice on one side of the wall that there is a barrier between it and a transponder and the transponders on the other side should react as if the reader is in the normal application environment without a wall.

According to the invention, this object is achieved in that the signal generated by a reading station is received by means of a resonator-assisted reception concept or an equivalent arrangement and by means of an overlay or mixing concept (of so-called heterodyne and / or heterodyne transponders) using additional signal frequency sources for the reference transmitter , local oscillators or other signal sources can be used) is transformed to a signal with a very low signal frequency. This low-frequency signal can penetrate the wall by means of magnetic or electric fields, sound or light without major problems. On the other side of the wall (also by means of heterodyne transponder or heterodyne) this low frequency is also mixed with a signal from a local oscillator and transformed into a (different) RF signal with the same or different frequency as in front of the wall. The frequency used by the reading unit in front of the wall can thus and so on. U. also be used behind the wall, or be converted to a very different frequency. The respective modulation of the primary interrogation signal is maintained.

In this case, the energy for the low-frequency signal, which can also overcome light, sound, vibration, etc., the wall by means of magnetic or electric fields, from the signal of the local oscillator (or another source) can be obtained, so that with only low energy received signal contents can be passed through the wall.

The low-frequency signal, which is finally present on the other side of the wall, is again mixed here with the signal of a local oscillator (or another source), and thus transformed again to a high, suitable frequency. The high-frequency signal formed in this case can substantially meet its energy requirement from this signal of the local oscillator, so that the energy requirement can also be suitably satisfied on this other wall side.

In this context, special material properties may play a role and should be considered. In fact, almost always materials show a frequency-dependent attenuation curve, which can sometimes change abruptly. Sometimes, in the frequency response (sometimes in surprising places), there are attenuation minima that can be well used for transmission. Various modern textiles and metamaterials have such places very clearly. Since the reading stations and the transponder i. a. Using frequency ranges (eg ISM frequencies), these and the frequency of any attenuation minimum present in a given material, are usually not compatible.

In this case, it is sufficient to transform the frequency used by the reading stations in each case by means of heterodyning or heterodyne transponder with the method according to the invention to the frequency with the best wall permeability, to send them through the wall and there to transform back to the ISM frequency.

However, this represents only a special case of the method according to the invention, because the use of low frequencies in the wall transfer based on the finding that a good wall permeability is located in the low frequency range. Of course, if a certain higher frequency has equally good or even better wall permeability, then it is comparably suitable and certainly offers some advantages.

When using sound (ultrasound) to transmit the signals across a barrier of given material and given wall thickness resonance points may occur in which the transmission with the sound used at a defined frequency can work very well, but also very bad. Such effects are to be considered in the same sense as a material property (although in this case they may not be).

When using sound (ultrasound) to transmit signals across a barrier, there may be different resonance points in each layer, especially in stratified structures, where the transmission with the sound used in the respective layer at a defined frequency can work particularly well. In this case, it may make sense to perform the adaptation of the frequencies in a stepped manner (for each layer individually) to the respective "layer frequency". For this purpose, overlay or heterodyne transponders must be provided at each material layer beginning and at each material layer end, which make the respective adaptation to the best possible frequency of the next stage. In this case, it is even conceivable to bridge some partial layers by wire. In this context, thought is given to residual garbage cast in several layers in which special measuring transponders have been welded in. Also sublayers with such effects are to be considered in the same sense as a material property (although in this case they may not be).

It should be noted as a special feature in applications in closed cavities that such cavities can themselves have resonator properties (also for electromagnetic fields). Certain frequencies that enter or are generated inside the container may depend on the material of the wall and the material of the content, on the construction (eg length / height / width), also the location of the antenna, but also on the antenna (Variable) content of the container dependent, standing in the cavity interior waves and / or constructive or destructive interference, so that within the container in certain places good or bad working conditions can be present, which are hardly predictable.

Thus, the choice of the frequencies used in the interior of the particular application is subject to more accurate evaluation. Under certain circumstances, it is therefore necessary to work inside a container with more than one frequency and u. U. also staggered frequency concepts are to be included. Such concepts can be realized by multiple use of the technique of the invention.

A suitable construction of the arrangement allows to activate the local oscillators (or the other sources for providing the signal at a second frequency) only when a received signal is already present and / or a signal carried by the wall. Thus, power-saving concepts of the invention can be realized. It is also u. U. possible, through the wall, z. B. by means of a low-frequency inductive coupling to transport enough energy to provide so behind the wall enough energy for the application can. This is especially useful for permanently messed-up, sealed or secured containers, barrels and areas.

For further description, it is useful to define the terms used.

The method partly uses a "resonator-assisted reception concept" during reception. Resonators of the type used here usually have only two functional components, namely an inductance and a capacitance and have i. a. no direct contact with other parts of a circuit. This special property, that they are only there to vibrate and to collect energy in these vibrations, distinguishes their function from a "normal oscillatory circuit". They are therefore referred to here as a distinction to other resonant circuits as "resonators", although of course they also represent a resonant circuit in itself.

The use of such resonant structures makes it possible to collect enough energy at the respective place, disconnect and transfer energy and data over a considerable distance. In a sense, such a resonator neither belongs to the primary circuit (even if it is located close to it) nor to the secondary circuit (even if it is located in its vicinity). On the other hand, these resonators belong both to the primary-side circuit (even if they are arranged on the secondary side) also to the secondary-side circle (even if they are arranged on the primary side). In another sense, an LC resonator on the one hand a parallel resonant circuit (consequent with the ability to current overshoot), on the other hand, a series resonant circuit (consequent with the possibility of voltage overshoot). There is no further, energy-withdrawing galvanic tap At the resonant structure, both aspects are inseparable, equivalent and simultaneous (with the need to take this into account in component selection).

Resonators on the same frequency, each one transmitter side (also: "primary side") and a receiver side (also "secondary side") arranged, so to speak form functional units, which are referred to as "resonator pairs".

The use of several resonators designed for the same and / or different frequencies is possible and this may support the same or different frequencies.

The terms "overlay transponder", "heterodyne transponder" and / or "heterodyne transformer" and also "transponder" already used are often used essentially interchangeably. This happens because of a generally difficult concept or word assignment.

• – zum Empfang bzw. zur Aufnahme eines oder mehrerer Signale (drahtlos, aber durchaus auch an materiegebundenen, z. B. Schall) geeignet ist und die
• – (praktisch gleichzeitig, aber nicht unbedingt zur gleichen Zeit) zum Aussenden und/oder zur Weitergabe eines oder mehrerer, anderer Signale (ebenfalls drahtlos oder materiegebundenen, i. a. auf einer anderen Frequenz)

geeignet ist. Das Kunstwort „Transponder”, gebildet aus „Transceiver” und „Responder”, beschreibt ja eben genau diesen Umstand; dabei ist „Transponder” ein dem Fachmann bekannter Begriff.As a "transponder" is to be seen any kind of entity that

• - to receive or to receive one or more signals (wireless, but certainly also to matter-bound, eg., Sound) is suitable and the
• - (virtually simultaneously, but not necessarily at the same time) to broadcast and / or transmit one or more other signals (also wireless or matter-bound, generally on a different frequency)

suitable is. The artificial word "transponder", formed of "transceiver" and "responder", precisely describes this circumstance; In this case, "transponder" is a term known to the expert.

The formation of a (above all by multiplicative linkage, but not only thereby formed) mixed signal, or one (ia by an additive link, but not only thereby formed) overlay signal are undoubtedly known, technical processes. The terms "mixed signal" or "superposition" and "superposition signal" are also known terms. The "mixing" of signals as well as the "overlay" z. As fields, a known, elemental, physical events based. The mixing or superposition signal thus generated (not only in a technical unit) is known to be generated from two signals with (usually) different frequencies.

It is now more general (also and especially technical) usage to presuppose a specific property of a technical unit as an adjective of the normal designation, and then to tie it together in the context of a substantiation into a concept. (Thus, a designation such as "an infrared light-sensing instrument measuring temperature" using a "infrared thermometer" will eventually become "infrared thermometer" or "IR thermometer", although "clay-built" as "clay building "But no one has ever seen a thermometer made of infrared"). Here the language offers liberties in the interpretation to which we appeal.

In the same sense, a description should be used here, so z. B. "one of two signals with different frequency a mixing or overlay signal forming and from the mixed or overlay signals a signal with a third frequency dissipative, both transmitting and receiving wireless unit" (which is yes here) in several steps meaningful and linguistically perfect in a term pack. It should be noted that the ultimately unavoidable numerical assignment (indexing) to the signals and frequencies on the one hand remains unique and helpful in a description as helpful.

From this point of view, the objects that are in focus here, which are "... transmitting and receiving radio units ...", are elements known from the state of the art, which in this context are characterized by (not introduced by us) ) Designation "transponder" are to be named. Alternatively, they may alternatively be referred to as "transformers" (frequency conversion).

Also, "a two signals with different frequencies a mixing or overlay signal forming ... wireless unit ...." is known in the art by the so-called heterodyne technique (of receivers), but i. a. Include a multiplicative link between the signals. The property to be described in the present context can thus be clearly preceded by the preposition of "heterodyne", "overlay" or "mixed" in the sense of a "description describing the nature of the technical unit" of the respective designation of the technical unit. (Otherwise "heterodyne receiver" would not be allowed).

Thus, it is merely normal usage to speak in this context of a "heterodyne transponder", "heterodyne transformer" or "superposition transponder" to represent the technical characteristics of the object to be described.

The fact associated with the inventive concept also that always three signals or three signal frequencies are necessary for the design of the transponder functions seen here, leads to the fact that the three signal frequencies are always distinguished by the terms "first frequency" (as a property of a "first Signal ")," second frequency "(as a property of a" second signal ") and" third frequency "(as a property of a" third signal "). The terms "first signal" and "a signal with a first frequency" are often equivalent in context; however, the term "first signal" can be used more unspecifically.

The following definition applies (cf. ): a first signal ( 53 ) (of three signals that generally occur in the function of the object), the one transponder ( 57 ), will have a defined carrier frequency range (ie, one, but possibly also have multiple frequencies). In the context of the "special" transponders considered here, such a "first signal" can always be understood as "a first signal with (at least) a first frequency" and can also be designated as such. However, since quite a few signals with these properties can reach the receiving part of the transponder, the case "(at least) a signal with (at least) a first frequency" also occurs quite well. This seems to be clear to us. (The phrase "a second signal with a second frequency" ( 55 ), "A second signal having at least a first, second frequency" and "(at least) a second signal having (at least) a first, second frequency" is then also clear and clear).

It has been found that the distinctness of the three signals in the normal speech flow achievable with this choice of words is useful in the description.

Of course, these terms also serve as a delimitation against the known in the art transponder. However, the name does not represent a new, fictional word creation.

One uses, as described, also following the normal usage, for the assignment of the three signals always occurring in connection with this specific transponder one, seen from the perspective of the transponder and the meaning of these signals suitable, firmly maintained and thus unique numbering, then lies the terminology used in this work. "First signal" and "first frequency" are in this sense their own terms.

From the DE 10 2008 056 928 the applicant knows the overlay transponders so defined. In these there are at least three resonators, two of which are provided for receiving a first signal at a first frequency or for providing a second signal at a second frequency (at their respective resonant frequencies). These two signals produce a superposition signal or a mixed signal. From the resulting frequency mixture new frequencies are formed (by non-linear function). Again by means of resonators energy is collected on these newly formed frequencies, provided and also brought to the broadcast.

• – Einen ersten Resonator (27a) zum Sammeln von Energie auf einer ersten Frequenz für ein zu empfangendes erstes Signal (23),
• – einen zweiten Resonator (27b) zum Sammeln von Energie auf einer zweiten Frequenz (die aus beliebiger Quelle (22) bereitgestellt werden kann oder die direkt genutzt wird),
• – eine Nichtlinearität (27d) (oder Mischeinheit), durch die aus dem Überlagerungssignal mit der ersten und zweiten Frequenz neue Frequenzen, z. B. die Differenzfrequenz entstehen und
• – einen dritten Resonator (27c), der Energie auf einer dieser neu entstandenen Frequenz sammelt und zur Nutzung bereitstellt, und u. U. dieses Signal (24) (mit der neu erzeugten dritten Frequenz) auch wieder abstrahlt.

From this, the construction of a unit operating independently of the primary transmitting unit and the destination receiving unit (just a superimposition transponder, cf. ), which can be designed actively (with its own power supply), semi-passive (power supply only for defined functions, not for signal transmission) or passive (without its own power supply) and which contains the following functional components (cf. ):

• A first resonator ( 27a ) for collecting energy at a first frequency for a first signal to be received ( 23 )
• A second resonator ( 27b ) for collecting energy at a second frequency (from any source ( 22 ) or that is used directly),
• - a nonlinearity ( 27d ) (or mixing unit), by the new signals from the overlay signal with the first and second frequencies, z. B. arise the difference frequency and
• A third resonator ( 27c ), which collects energy at one of these newly created frequencies and makes it available for use, and u. U. this signal ( 24 ) (with the newly generated third frequency) also radiates again.

In the teaching of reception techniques, the so-called heterodyne receivers or heterodyne receivers provide well-known reception techniques (cf. ; Details with the same meaning are u. U. referred the same). Here are the from an antenna ( 6 ) carrier frequency signals (after a possibly after the antenna circuit following low-noise amplification ( 7 )) of a mixing stage ( 8th ). In such a mixer, the signal received by the antenna is transmitted with a signal ( 10 ) from a local oscillator ( 9 ) (ia multiplicatively) linked.

The aim of such a link is the simulation of a mathematical operation, z. B. a multiplication. If the received signal ( 5 ) with such a signal ( 10 multiplied), this results in the so-called mixing or superposition signal ( 11 ) of the z. B. after a low or high pass filtering ( 12 ) the so-called intermediate frequency signal remains.

It can be shown in general that with the antenna ( 6 ) received carrier frequency signal ( 5 ) and the low-frequency or higher-frequency intermediate-frequency signal ( 11 ) have the same signal characteristics relevant here, from which it follows that all the proportions of the high-frequency carrier signal are retained in the low-frequency (but also in the high-frequency) signal component of the mixed signal, including all modulation-related manipulations on the high-frequency carrier signal, regardless of the type of modulation (amplitude, Frequency, phase, or any other modulation designed). It has - albeit with a limited bandwidth - the same time and spectral course in principle, as well as the received high-frequency signal, only the spectrum is now in another place in the frequency domain.

The signal ( 10 ) of the local oscillator ( 9 ) causes u. U. also an amplification of the received components, wherein the energy for this gain can be obtained from the energy of the signal of the local oscillator.

In this sense, such an arrangement also represents a frequency transformer for adapting the one (received) frequency range to a second (intermediate) frequency range and is therefore (see the above definition) hereinafter referred to as "heterodyne transformer" or "heterodyne Transponder "are generally detected.

• – ein (erstes) Signal (5) auf einer ersten Frequenz f₁,
• – verwendet intern ein (weiteres) zweites Signal (10) mit einer (anderen) zweiten Frequenz f₂,
• – bildet aus diesen beiden Signalen mittels Mischstufe (8) (i. a. aktiv) ein (weiteres) drittes Signal (11) aus, das eine (andere) dritte Frequenz f₃ aufweist und
• – sendet (nach Filterung (12)) ein Signal (15) mit dieser dritten Frequenz f₃ wieder aus.

In summary, therefore, receives a heterodyne transformer or heterodyne transponder

• A (first) signal ( 5 ) at a first frequency f ₁ ,
• - internally uses a (further) second signal ( 10 ) with a (different) second frequency f ₂ ,
• - forms from these two signals by means of mixing stage ( 8th ) (ia active) a (further) third signal ( 11 ), which has a (other) third frequency f ₃ and
• - sends (after filtering ( 12 )) a signal ( 15 ) with this third frequency f ₃ again.

• – Einen Antennenkreis (6) (16) zum Empfang von Signalen (5) auf einer ersten Frequenz, die
• – evtl. noch durch einen rauscharmen Verstärker (7) verstärkt wird,
• – einen lokalen Oszillator (9) zum Bereitstellen eines zweiten Signals (10) mit einer zweiten Frequenz (das aber auch aus einer beliebig anderen Quelle bereitgestellt werden kann),
• – eine (aktive) Mischeinheit (8), die die beiden Signale (i. a. multiplikativ) verknüpft und das Mischprodukt (11) nach einer Filterung (12)
• – evtl. noch einmal durch eine Verstärkerstufe (13) verstärkt, auf
• – einen zweiten Antennenkreis (14) (17) schaltet und dieses so zur Abstrahlung bereitstellt (15).

For this purpose, a heterodyne transformer or heterodyne transponder contains the following functional components:

• - an antenna circuit ( 6 ) ( 16 ) for receiving signals ( 5 ) on a first frequency, the
• - possibly with a low-noise amplifier ( 7 ),
• A local oscillator ( 9 ) for providing a second signal ( 10 ) with a second frequency (but which can also be provided from any other source),
• An (active) mixing unit ( 8th ), which links the two signals (ia multiplicatively) and the mixed product ( 11 ) after filtering ( 12 )
• - possibly again through an amplifier stage ( 13 ), up
• A second antenna circuit ( 14 ) ( 17 ) and this provides for the radiation ( 15 ).

The overlay transponders described above are thus to be clearly distinguished with respect to their arrangements of such heterodyne transformers or heterodyne transponders.

A superimposition transponder can be designed to be passive, semi-active or active, wherein the superimposition of the resonator (passive) received first signal (with the first frequency) and the signal with the - provided anyway - second frequency i. a. passively, and the (passive) provision of a signal with the third frequency derived from the superimposition signal also takes place by means of a resonator.

Heterodyne transformers or heterodyne transponders can be configured semi-actively or actively (but only to a very limited extent passive) because the mixer i. a. will be an active circuit, the amplifier circuits as well.

Both arrangements show, however, despite differences in each other in transition constructive properties and undoubtedly a similar function:
An overlay transponder receives a signal at a first frequency f ₁ , transmits a signal at frequency f ₃ again and uses an additional signal with the frequency f ₂ for this transformation. The combination of f ₁ and f ₂ is generally additive and can be done passively.

A heterodyne transponder receives a signal at a first frequency f ₁ , sends out a signal at frequency f ₃ again and uses an additional signal with the frequency f ₂ for this transformation. The combination of f ₁ and f ₂ is generally multiplicative and is generally active.

Both constructions flow into each other fluently and both are as external units on the one hand neither the transmitter nor the receiver attributable, on the other hand both the transmitter and the receiver.

shows the typical switching arrangement of a heterodyne transponder, above as a circuit diagram ( 1a ), below as a block diagram ( 1b ). The respective transponder arrangement ( 1a ) 1b ) receives from a transmitting station ( 2 ) incoming carrier signal ( 5 ) having a first frequency f ₁ , by means of an antenna arrangement ( 6 ) 16 ), whose structure can be designed differently depending on the frequency range used. A local oscillator ( 9 ) the required signal ( 10 ) with the second frequency f ₂ , but this signal can also be generated by any other method or supplied to the unit.

The resulting mixed signal ( 11 ) contains frequencies that can be filtered by a suitable filter stage ( 12 ) can be filtered out specifically. The filtered signal (after any amplification ( 13 )) via a further coil arrangement ( 14 ) or antenna ( 17 ) on another, third frequency f ₃ ( 15 ).

shows the arrangement of an overlay transponder ( 21 ) 30 ) and ( 40 ).

In the above is a transmitting station ( 20 ) and an overlay transponder ( 21 ), which at a first frequency f _{1 is} a signal ( 23 ) from the transmitting station ( 20 ) receives wirelessly, and after appropriate transformation a signal at a third frequency f ₃ passes ( 24 ). The signal ( 25 ) with the frequency f ₂ , which normally comes from a local oscillator, is used here with the transmission arrangement ( 22 ) via a transmitting or antenna arrangement ( 27b ) provided.

• – für den Empfang eines Signals auf einer ersten Frequenz (33),
• – für die Übernahme eines Signals (35) von einem (fiktiven) Generator (34) auf einer zweiten Frequenz f₂ und
• – zum Sammeln von Energie auf einer dritten Frequenz f₃, die zur Abstrahlung eines Signals (39) vorgesehen.

A real construction is with the the overlay transponder consists of three circuits mounted on a (not necessarily flexible) board ( 30 ), (in also ( 47 )) have been applied. The from a first coil ( 31a ), a second coil ( 32a ) and a third coil ( 36a ) with associated capacitors ( 31b ) 32b ) and ( 36b ) existing resonator arrangements should be designed to be passive and are

• For receiving a signal at a first frequency ( 33 )
• - for receiving a signal ( 35 ) of a (fictional) generator ( 34 ) on a second frequency f ₂ and
• For collecting energy at a third frequency f ₃ , which is used to emit a signal ( 39 ) intended.

The shows the used function symbol for an overlay transponder, which is to be inferred from the previously shown immediately: This function symbol is in principle a side view of , The carrier material of the board ( 47 ) carries on one side the printed coil / capacitor arrangement ( 48 ) for collecting and radiating energy at a third frequency ( 49 ), on the opposite side the two resonator arrangements ( 43 ) and ( 46 ) for receiving signals ( 42 ) on a first frequency transmitted by a transmitter ( 41 ) in the direction of the overlay transponder ( 40 ) are radiated. On this page is also the resonator ( 46 ) for collecting energy at a second frequency ( 45 ) whose origin in the function symbol is only indicated by a generator symbol ( 44 ) should be indicated. In fact, the origin of this second frequency is determined by the respective applications and is not intended exclusively by a local oscillator ( 44 ) to be provided. The required nonlinearity must be additionally provided (not shown).

The assignment of the components involved in the event in the overlay transponder are in the three representations . and recognizable by comparison.

Regardless of the details, with the representation of an overlay transponder by the function symbol of the and with the representation of a heterodyne transponder of the representation of the idea according to the invention take place. The presentation of the can be used for both types of transponders, the functional assignment of the displayed elements is seen as the same in both cases:
A receiving arrangement (ie a resonator in the overlay transponder and an antenna circuit in the case of the heterodyne transponder) is shown in FIG the upper rectangle ( 58 ) on the left side of the board ( 57 ) of the function symbol. The wirelessly received signal ( 53 ) is indicated by a radio symbol in the to represented ( 52 ) 53 ) 54 ).

An arrangement for providing a second signal having a second frequency ( 55 ) ( 56 ) is the underlying rectangle ( 60 ). The associated signal ( 56 ) with this second frequency can be received; In this case, this is also indicated by a radio symbol ( 56 ) or can be generated by a local oscillator, which is then indicated by a corresponding generator symbol ( 55 ), etc.

The two signals (with the first and second frequencies) are superimposed additively in the overlay transponder simply by the spatial proximity of the two coils and can thereby form a signal mixture that is characterized by a nonlinearity ( , ( 27a )) provides new signal components. All components needed for this and everything else that this arrangement still needs, is simply the board ( 57 ) thought unspecifically assigned.

The collection of energy from such a newly formed frequency component of the beat signal is again realized by means of a resonator (in the superposition transponder) and is in the function symbol the rectangle on the other side ( 59 ) of the board ( 57 ) arranged arranged. In a heterodyne transponder, the filter stage and the corresponding antenna arrangement can be seen integrated therein.

The signal emitted here again ( 54 ) (ie the third signal with a third frequency) is again represented by a radio symbol ( 54 )

Thus, there is the following situation: by means of the heterodyne transformers or overlay transponders, frequency adjustments between frequency-incompatible radio stations can be realized both upwards and downwards. If these stations are active or semi-active, they can also be considered as reinforcing elements.

In principle, a frequency down-conversion can result in a few kilohertz or even hertz, so that extremely low frequencies that can be used for wall penetration can be formed. But also suitable damping windows are usable. The adaptation of the frequencies and bandwidths to the required baud rate must be observed.

Since overlay transponders and / or heterodyne transponders are capable of both up and down conversion, it is possible to negotiate a distance up to a first overlay transponder with a relatively high frequency, with this overlay transponder a frequency conversion (to a very low frequency or up) a frequency window), with this (low or appropriate) frequency to penetrate a dense wall, on the back of the wall to resume this signal with another heterodyne transponder or heterodyne and transform to another frequency, and behind this wall with this Frequency turn a larger distance to the target transponder to bridge.

The shows the principle of this transmission: a transmitting station ( 61 ) with antenna ( 62 ) or a similar arrangement ( 72 ) transmits an arbitrarily modulated signal on a defined carrier frequency ( 67 ) ( 73 ) with a first frequency in the direction of a wall which is not permeable to this HF ( 69 ). At a defined distance to this wall there is an overlay transponder ( 78 ) has the resonators suitable for receiving this signal, or a heterodyne transponder ( 66 ), whose antenna arrangement is designed appropriately. Both alternatives use the signal of a local oscillator (eg 77 )) (or a signal of other origin) with a second frequency.

The wall penetrating low frequency signal ( 68 ) ( 70 ) does not necessarily have to be electromagnetic in nature, but can use a very different carrier medium, eg. As sound (ultrasound, vibration, etc.), magnetic and electric fields, light, etc.

If this frequency is very low, it is u. U. also able to act as an electromagnetic field ( 68 ) to penetrate the wall and hits in this example on the other side of the wall on a resonator structure ( 71 ), which stimulates it. This resonator structure may, in turn, be part of a superposition transponder composed of this signal and a signal of a (different) local oscillator ( 76 ) forms a mixed signal from which a signal with the sum frequency is formed by means of a filter arrangement and can be radiated on the other side of the barrier ( 75 ).

If this sum frequency now comes on this side of the wall to the radiation, then also this signal has again all characteristics, which also the original signal wist.

Are the frequencies of the local oscillators used in these two transponders ( 77 ) ( 76 ), then the signal emitted behind the wall ( 75 ) exactly the same frequency as the signal ( 73 ), which had been used by the reading station.

Since the modulation characteristics of the signal are retained in the second superimposition transponder in this case as well, the overall function of this arrangement, which consists of two heterodyne or superposition transponders, can be functionally interpreted as if the signal had ( 73 ) ( 67 ) of reading stations ( 72 ) ( 61 ) simply penetrates the RF-dense wall.

At this point, the symmetry of the arrangement is to be considered: The overlay transponders used on both sides of the wall are identical in construction and have practically the same functionality for the outward and return journey. This is not the case when using heterodyne transponders; here separate branches must be set up for the round trip.

The example of shows a transmission of high-frequency signals by means of low-frequency, electromagnetic fields through a barrier ( 94 ) using two overlay transponders ( 82 ) ( 83 ). Between a transmitting station ( 81 ) and a receiving station ( 84 ) is one, for the frequency used by these stations, impenetrable barrier ( 94 ). That of the station ( 81 ) sent signal ( 95 ), which may have any modulation, reaches the overlay transponder located on the same side of the barrier ( 82 ). An on the frequency of the transmitting station ( 81 ) tuned resonator ( 96 ) collects energy in the transponder on this frequency.

The overlay transponder ( 82 ) receives a second signal from any source, symbolized here by a generator symbol ( 85 ), with a second frequency, from which by means of a second resonator ( 86 ) Energy is provided. The two fields of the inductors of the resonators ( 96 ) 86 ) overlap and form an electromagnetic sum field.

A nonlinearity ( 97 ) generates signals with new frequencies from this field frequency mixture.

Here the focus is on the formation of a low frequency, so that in this example only the difference frequency comes into question, to which this superimposition transponder a third resonator ( 98 ), which collects energy at this third frequency from the frequency mixture formed and provides.

The resulting low-frequency signal component is suitable for non-permeable higher-frequency barrier ( 94 ) to overcome ( 87 ) and gets to the other side of the barrier.

On this side of the barrier is another overlay transponder ( 83 ), with a resonator ( 99 ), which is also tuned to this low difference frequency and collects energy from the low frequency signal coming through the wall. This (practically identical) overlay transponder also uses a signal from a local oscillator ( 93 ) which provides on this side of the barrier a second frequency signal.

In this superimposition transponder, the inductances of the two resonators ( 99 ) and ( 106 ) a sum field from which arise in a known manner by a nonlinearity, new frequencies. On this side of the barrier is through the third resonator ( 119 ) in the overlay transponder ( 83 ) again energy from the frequency mixture, but now collected at the sum frequency, provided and in the direction of the receiving station ( 84 ).

If the frequency of local generators ( 85 ) and ( 93 ) is equal, then the frequencies of the signals are left ( 95 ) and right ( 118 ) from the barrier equal and the transmitting station ( 81 ), the receiving station ( 84 ) to reach.

In Below, the same is shown again with the introduced function symbols: The carrier signal coming from a transmitter ( 91 ) is transmitted from the left-side overlay transponder to a carrier signal ( 88 ) with one to penetrate the barrier ( 94 ) suitable frequency, penetrates ( 88 ) the barrier and is returned to the original carrier frequency by a right-side overlay transponder ( 92 ). For this purpose, both superposition transponders set local oscillators ( 89 ) ( 90 ) with the same frequency.

represents the principle of such a transfer over a barrier by means of another medium, here exemplified by ultrasound:
The transmitting station ( 100 ) sends a signal with arbitrary modulation ( 110 ) in the direction of a wall ( 114 ), on which there are two overlay transponders on both sides.

The first overlay transponder ( 109 ) receives the signal ( 110 ) by means of a resonator and transforms it by means of a second signal ( 101 ), a nonlinearity ( 112 ), and a third resonator ( 108 ) on a low, here ultrasonic frequency.

This can z. B. a piezoelectric element ( 117 ), which, with its capacitance, together with a suitably dimensioned inductance ( 108 ), directly provides the required resonator at the difference frequency and at the same time allows ultrasonic coupling into the wall.

The ultrasound signal ( 115 ) penetrates the wall ( 114 ) and reaches the piezo element ( 116 ) of a practically identical overlay transponder ( 105 ). This piezo element is part of a resonator, which consists of the capacitance of this piezo element ( 116 ) and an inductance ( 107 ) and collects energy from the received ultrasound signal.

The resulting oscillating resonator provides by the integrated inductance ( 107 ) provides an alternating field that matches the field of the local oscillator ( 102 superimposed) supplied signal from which the non-linearity ( 113 ) gives rise to a frequency mixture with a summation field component from which the third resonator draws and radiates energy ( 104 ), which finally determines the target receiving component ( 103 ) reached.

The combination of the capacitance of the piezo element and an inductance used here for a resonator is not necessarily the most favorable; an LC resonator with inductively coupled Piezo element can u. May (but not always) provide better results.

Finally, it should be mentioned that the frequency transformation must, of course, take into account the bandwidth of the signals required for the respective modulation.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008056928 [0057]

Claims (9)

A method for transmitting modulated high-frequency signals from a transmitting station via an RF-dense wall to a receiving station, characterized in that each directly in front of and behind the RF-dense wall overlay or heterodyne transponders are used, which as autonomous to be seen units neither to the respective Transmitters still belong to the respective receiver, - wherein a first heterodyne transponder or heterodyne on one side of the wall - receives the signals generated by a transmitting station, - transforms these signals to a waveform with which the RF-dense wall can be overcome, - and in this form sends through the wall to the other side and - a second heterodyne transponder on the other side of the wall - receives the signals coming through the wall, - transforms these into signals which are adapted to the respective receiving station and - in the room behind the Wand radiated, whereby the signals received in front of the wall are passed to the respective receiving station behind the wall. A method according to claim 1, characterized in that the wall penetrating signals by means of electromagnetic, magnetic or electric fields, by means of light, and infrared, by means of sound, and ultrasound, vibrations or vibrations are transmitted. Method according to one of claims 1 to 2, characterized in that the wall penetrating signals are transmitted by wire or by capacitive coupling, inductive coupling, optical coupling, or mechanical coupling and sound coupling to the other side of the wall. Method according to at least one of Claims 1-3, characterized in that the signals received in front of the wall and the signals passed on behind the wall can operate with the same or different frequency. Method according to at least one of claims 1-4, characterized in that the signal used in the heterodyne or heterodyne transponder with a second frequency, which is used to form a heterodyne signal from the received signal at a first frequency, wired or wirelessly supplied to the superimposition transponder is what can be done by local oscillators or from any other source, so reference transmitter, optical transmission, wired supply, sound source, by means of electromagnetic fields. Method according to at least one of claims 1-5, characterized in that the signal used in the heterodyne or heterodyne transponder with a second frequency, which is used to form a heterodyne signal from the received signal having a first frequency, on both sides, the same or the wall can be different Method according to at least one of Claims 1-6, characterized in that the upward or downward adjustment of signal frequencies taking place on both sides of an HF-tight wall takes place in several stages using a plurality of overlay transponders. A method according to claim 7, characterized in that the adaptation in stages within an RF-dense wall at the layer boundaries of the layers from which the wall may be constructed, takes place stepwise. Method according to at least one of claims 1-8, characterized in that the supply of a signal at the required second frequency or the activation of the local oscillators by the receipt of another signal, preferably the signal with the first receiving carrier frequency, is carried out to low-current To be able to train concepts.

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