WO2021115536A1

WO2021115536A1 - Variable capacitor system for impedance matching

Info

Publication number: WO2021115536A1
Application number: PCT/DE2020/101039
Authority: WO
Inventors: Christoph Bromberger
Original assignee: Kiefel Gmbh
Priority date: 2019-12-09
Filing date: 2020-12-08
Publication date: 2021-06-17

Abstract

The invention relates to a variable capacitor system (1) for impedance matching, a matching network (4) comprising said type of variable capacitor system (1), a system (10) comprising said type of matching network (4) and to a use of the variable capacitor system (1) for impedance matching, formed by a parallel or series connection of a variable transducer (11) with a capacitor (12). The invention also relates to a method (100) for controlling said type of impedance matching network (4).

Description

VARIABLE CONDENSER SYSTEM FOR IMPEDANCE ADAPTATION

Field of invention

The invention relates to a variable capacitor system for impedance matching, a matching network with such a variable capacitor system, a system comprising such a matching network and a use of the variable capacitor system for impedance matching, and a method for regulating such a matching network for impedance matching.

Background of the invention

A signal source is connected to a load via a dual directional coupler and a variable matching network for impedance matching. The signal source has an output with an internal source impedance, the load an input with a load impedance. The variable matching network has an input connected to the output of the signal source via the directional coupler and an output connected to the input of the load. The signal source emits a source signal with a signal frequency. In the input of the variable matching network, an input impedance acts on the source signal, which is transported by means of the directional coupler from the signal source to the input of the variable matching network. The signal with a source impedance is emitted from the output of the directional coupler. Part of the signal is reflected back to the source at the input of the variable matching network.

In addition to a directional coupler input which is connected to the output of the signal source, the directional coupler has a directional coupler output which is connected to the input of the variable matching network. The directional coupler also has a forward coupling port and a reverse coupling port. The directional coupler generates a forward signal on the forward coupling port which is proportional to the source signal. The directional coupler generates a backward signal on the backward coupling port, which is proportional to the portion of the source signal reflected back to the source at the input of the variable matching network. A mismatch between the source impedance and the input impedance can be determined from the ratio of the powers of the forward signal and the reverse signal according to the methods known from the prior art. In addition, the input impedance itself can be determined from the source impedance and the amount and phase of the forward and backward signal. The transformation effect of the variable matching network is influenced by the values of a first number of control signals. The aim of this influencing can be to minimize the mismatch.

From the document US 4,951,009 variable matching networks with a first variable reactance and a second variable reactance are known. The value of the first variable reactance is controlled with the aid of a first control signal, the value of the second variable reactance is controlled with the aid of a second control signal. In the automatic adjustment of the variable matching network, the most complete possible reduction in the amount of the input reflection is used as the target variable, the first control signal and the second control signal as control variables. As part of an automatic adjustment, the first control signal is applied with a variation of its value by a small amount with a first variation frequency and the second control signal with a variation of its value by a small amount with a second variation frequency. The change in the target variable is related to the variation in the manipulated variables. Starting from this, the target variable is optimized by suitable adaptation of the values of the manipulated variables.

Furthermore, prior art are so-called varactors, in which the change in capacitance is based on the change in a bias voltage across a space charge zone between oppositely doped semiconductor regions. If they also make electrically variable capacitance values available, they seem hardly suitable for building high-performance matching networks in an economically justifiable manner.

The prior art also knows capacitors with a field strength-dependent dielectric constant of a dielectric. Of course, these are only for Suitable for small-signal operation - the capacitance is modulated by applying a high AC voltage.

The disadvantage of the prior art is therefore that it does not provide any capacitors whose capacitance value can be changed rapidly and continuously in terms of their capacitance value.

Summary of the invention

The invention is based on the object of providing a variable capacitor which does not show the above disadvantages.

The object of the invention is achieved by a variable capacitor system for impedance matching from a parallel or series connection of a variable transducer with a capacitor. The capacitor used here does not need to be a variable capacitor, as the transducer itself is the variable actuator that, together with the capacitor in parallel or in series, acts like a variable overall capacitor without having to use a variable capacitor in the circuit. The transducer, which can be switched quickly, provides a rapidly and continuously variable overall capacitor in the form of the variable capacitor system.

The present invention thus provides a variable capacitor which does not exhibit the foregoing disadvantages of the prior art.

In one embodiment, the capacitor is a capacitor with a fixed capacitance value or a variable capacitance value, the capacitor for the latter preferably being designed as a vacuum capacitor or a variable capacitor. The capacitor and the transducer can be arranged as a parallel circuit.

In a further embodiment, the capacitor system further comprises an electronic control device which allows a capacitor value for the variable Adjust the capacitor system at least by means of the variable transducer for impedance matching

In another embodiment, the transducer is a high power, high frequency transducer. In a further embodiment, the transducer has a soft magnetic iron core, ferrite core or a saturable ferromagnetic core.

In a further embodiment, the transducer has a ring core, a rod core or an EI core. In the case of an EI core, the shell design is formed, for example, from alternately layered stacks of E- and I-shaped sheets. The invention further relates to a variable matching network for impedance matching, comprising one or more variable capacitor systems according to the invention as an actuator.

The invention further relates to a system comprising a signal source, a load, a directional coupler and a variable matching network according to the invention, the signal source being connected to the load via the directional coupler and the variable matching network for impedance matching.

The invention further relates to the use of one or more variable capacitors according to the invention of a matching network for impedance matching in a system according to the invention. It has been established that transducers are unsuitable for high frequency power matching networks because of inherent losses. Contrary to this prejudice, impedance-variable matching networks according to the invention are also suitable for matching extreme impedance ratios of 100: 1 in the range of 27 MHz and 50 kW high-frequency power. The invention also relates to a method for regulating a variable matching network according to the invention for impedance matching, comprising the following steps:

Measuring transformation matrices of the variable matching network for a set of predefined value tuples of a number of control signals; Measuring an input impedance seen into the input of the matching network for any tuple of values;

Determining a predefined value tuple that best approximates the arbitrary value tuple from the set of predefined value tuples of a number of control signals and one of the predefined value tuples in accordance with the transformation matrices; and

Calculating the load impedance on which the input impedance is based on the basis of the predefined value tuple that approximates as closely as possible and the associated transformation effect according to one of the transformation matrices.

Knowing the load impedance allows extensive conclusions to be drawn about the state of the load, which in many cases facilitate precise process control. The matching network can be used for a welding press, for example. For example, if the load is a package made of PVC film to be welded using high frequency, the remaining thickness and the temperature reached of the film package can be calculated from the area of the welding tool and the load impedance, provided that the temperature-dependent material parameters of the PVC film are known. This greatly simplifies precise process management.

A “matching network” is an electrical network that is suitable for impedance matching. "Impedance matching", also known as power matching, is used in high-frequency technology to optimally match a source of a signal to a load. If the impedance is not matched when transporting high-frequency power, this leads to standing waves on the line; this increases the load on the line, while at the same time not the full power is transferred from the generator to the load. On a line with completely standing wave no energy can be transported. The matching network can include capacitive and / or inductive elements. In the case of a welding press according to the invention, for example, a time-varying input impedance can be seen in the high-frequency input of the welding press. This can typically be in the region of 1 ohm. In contrast to a constant load, the impedance of the source must therefore be adapted to a load impedance that changes over time. Furthermore, the variable matching network according to the invention has an RF input and an RF output. The HF input of the welding press is connected to the HF output of the variable matching network. A high-frequency source feeds high-frequency power into the HF input of the variable matching network and, via the variable matching network, high-frequency power into the welding press. The high frequency source has an RF output with a source impedance. This source impedance can typically be 50 ohms. The HF output of the high frequency source is connected to the HF input of the matching network. High frequency power is optimally transmitted between a source and a load when the input impedance of the load and the output impedance of the source are complex conjugate at the operating frequency.

An “input-side matching” occurs when, while the high-frequency source feeds a high-frequency signal into the RF input of the variable matching network, the output impedance of the high-frequency source is matched to the input impedance of the variable matching network. The input impedance effective into the high-frequency signal in the HF input of the variable matching network therefore represents the load impedance for the high-frequency source. Power is optimally transmitted between the output of the high-frequency source and the RF input of the variable matching network when the output impedance of the high-frequency source and the input impedance of the variable matching network are complex conjugate to one another.

An “output-side adjustment” is related to the output of the variable adjustment network, if the variable adjustment network, on the other hand, is used as a “source” for High frequency power for the welding press works. Power is optimally transferred between the output of the variable matching network and the RF input of the welding press when the output impedance of the variable matching network and the input impedance of the welding press are complex conjugate to one another. If the variable matching network is essentially reciprocal and lossless, then there is an input-side adaptation precisely when there is an output-side adaptation.

A “transformation effect” describes the adaptation effect of the adaptation network, which can be controlled by a set of control variables at control inputs of the variable adaptation network. The transformation effect is measured between the input and the output of the variable matching network. The transformation effect cannot be limited to mapping input impedance to output impedance. Every “tuple” (also called “value tuple”) of control variables has a transformation effect.

A “transformation matrix” or “transformation effects matrix” is understood to be a one or more dimensional matrix with one or different transformation effects as matrix elements. The transformation effect (s) associated with the transformation matrix are selected by given circumstances (such as the state of the load, etc.). A transformation effect is determined by a tuple of control variables. The variable matching network according to the invention can in many cases be approximated as a linear system. Therefore, the transformation effect matrix can be, for example, an S-matrix. In an exemplary embodiment, the transformation effect can be measured directly with a vector network analyzer as an S-matrix if both the source and load impedance of the matching network are sufficiently close to 50 ohms. In another exemplary embodiment, the transformation effect in a non-linear matching network can be measured with a sufficiently powerful signal. The value of the load impedance of the welding press can be calculated on the basis of the input impedance of the network (eg the load impedance of a welding press transformed by the matching network) and the S-matrix. This can also apply to the calculation of the losses in the matching network. The Transformation effects can therefore be much more extensive than just a (complex) quotient of output and input impedance (not: signal).

"Control signals", also called "control variables" or "controlled variables" or similar, are understood to mean, for example, currents that are applied to the control inputs of the network. A set of control variables is referred to as “tuple” or “value tuple”. If a (first) transformation effect of the matching network is set, for example with the help of two independent currents II and 12, a value tuple would be a pair of specific values of these two control currents. Another tuple of values with different values of control currents results in a further transformation effect. The control variables or control currents II and 12 can be varied independently of one another in a range from e.g. 0A to as required. This creates a value tuple table, with each entry being assigned to a transformation effect.

Before the variable load to be measured is first applied (e.g. before the first welding in a welding press), transformation matrices of the variable matching network are measured for each value tuple from a set of predefined value tuples from a number of control signals in a method according to the invention. In each case, a transformation effect of the matching network according to the invention is measured for a predefined finite set of tuples of control variables t. The “transformation matrices for a set of predefined tuples of values for a number of control signals” are understood to mean, for example, the set of measured transformation effects of the matching network for predefined currents at a discrete support load. These transformation effects are also called “first transformation effect (s)”. The elements of the set are tuples of control variables, and each tuple from the set is assigned a measured transformation effect of the variable adaptation network. As an example, a transformation effect TW1 could be determined and included in the set of transformation matrices that are present for streams II and 12 via the matching network. A transformation effect TW2 could be determined in the same way for currents 13 and 14. The set and its elements, the tuples, are not changed at runtime Subsequently, in a step of the method according to the invention, an input impedance seen into the input of the matching network is measured for any tuple of values of control signals. With a variable load and with any value tuple (also called "second value tuple") of control signals (eg any II and 12), this input impedance seen into the input of the matching network is measured. The input impedance of the variable matching network and the output impedance of the high-frequency source for a welding press are typically in a range in which the power transport of high-frequency power is sensibly possible, for example 50 ohms. Directional couplers can accordingly be suitable for measuring forward and backward HF signals. The input impedance of the welding press, on the other hand, is typically in the region of 1 ohm. It is difficult to measure impedances here. In order to be able to measure the transformation effect of the variable matching network (from 50 ohms to 1 ohm), measuring adapters that can shift the 1 ohm back to around 50 ohms would be required. However, these are disadvantageous during the welding process. According to the invention, a transformation effect of the variable matching network and the impedance measured into its input are therefore used to calculate the impedance with which the output of the variable matching network is terminated, i.e. the input impedance of the welding press.

If there is complex conjugate matching between the high-frequency source and the input of the variable matching network, no power is reflected back from the input of the variable matching network into the output of the high-frequency source. The transformation effect of the variable matching network is set with the aid of control signals. It is possible to measure the reflection of the source power at the input of the variable matching network and to minimize it with the help of the control variables. For example, the power delivered by the high-frequency source to the variable matching network can be maximized. If the variable matching network were reciprocal and loss-free, the output of the variable matching network to the welding press would thereby also be maximized. In practice, however, it can actually happen that essentially the entire high-frequency power of the high-frequency source is converted into heat in the matching network. In this case, too, no power is reflected back to the high-frequency source at the input of the variable matching network, and “matching” prevails there. Therefore, only on the basis of measurements of the reflection at the input of the variable matching network, which can easily be measured, it is not possible to distinguish whether the power is essentially completely delivered to the welding press, essentially completely burned in the variable matching network, or whether there is any case in between .

Therefore it is not reliable to measure only the reflection between the high frequency source and the variable matching network. In the course of a weld, the impedance that affects the input of the welding press changes, as, for example, the geometry and conductivity of the foil to be welded changes. This also changes the reflection of the power between the high-frequency source and the input of the variable matching network. If the control signals are regulated in such a way that the reflection at the input of the matching network is minimized, a case would be possible in which the power is no longer output from the variable matching network to the welding press, but instead is burned in the variable matching network. The weld can then come to a standstill and the variable matching network can be damaged.

It is therefore advantageous to know the transformation effect of the variable adaptation network for each set of control variables so that, based on the measured reflection at the input of the variable adaptation network and the known transformation effect in the currently available set of control variables, one can see into the welding press Can calculate input impedance. The instantaneous losses in the variable matching network can also be calculated. Furthermore, this knowledge is advantageous, since the knowledge can be used to select the setting of the control signals in such a way that excessive power losses in the matching network can be avoided. However, it is not possible to measure the transformation effect of the variable matching network in advance for every possible set of control variables. It must be limited to the measurement of a finite set of predefined discrete value tuples of a number of control signals.

In a further step of a method according to the invention, a predefined value tuple that best approximates any value tuple is determined from the set of predefined value tuples of a number of control signals, as well as one of the predefined value tuples. In order to determine the variable load impedance, in addition to the measured input impedance, the currently prevailing transformation effect, the “second transformation effect”, is required via the matching network. The currently prevailing transformation effect cannot, however, be measured and is therefore approximately replaced by a transformation matrix, that is to say a first transformation effect, of the abovementioned set of transformation matrices. In an alternative embodiment, instead, several interpolation points close to the currently applied tuple of control signals are selected, for which interpolation points the transformation effects have been measured, and interpolation is carried out between these in order to be able to approximately determine the transformation effect for the currently applied tuple of control signals. In this embodiment too, the transformation effect of the variable matching network is approximately determined for the currently applied tuple of control signals.

If there is an actual tuple of control variables during commissioning (during a welding process) with a variable load (e.g. foil during welding) - for example one for which the transformation effect of the variable adaptation network has not already been measured in advance - a Such an approximation tuple from the set of tuples of control variables determines that the approximation tuple among all tuples from the set of tuples corresponds as closely as possible to the actual tuple, and the transformation effect of the variable matching network on the approximation tuple is used as an approximation to the actual transformation effect (ie the “second transformation effect”) of the variable matching network is used for the actual tuple of control variables.

In a further step of the method according to the invention, the load impedance on which the input impedance is based is approximately calculated based on the best possible approximating predefined value tuple and from the associated transformation effect according to the transformation effect matrix. In this case, the current impedance of the load is calculated from the input impedance measured above and the approximately known current transformation effect of the matching network, or determined approximately at its actual value. If the current load impedance is known, a new tuple of control signals can be determined by means of which the load impedance can be better matched to the desired load impedance for the amplifier by the variable matching network. Here, too, one can be selected from the predetermined transformation effects from the transformation effects matrix in which the approximately known impedance of the variable load is transformed as best as possible to the desired load impedance for the amplifier. In one embodiment, it is possible to interpolate between the known tuples of control signals and the associated, previously measured transformation effects in order to arrive at a suitable tuple of control signals by means of which the desired load impedance for the amplifier can be realized.

By iterating impedance measurement and adapting the control signals, a load change can be followed with the variable matching network in such a way that the amplifier is always operated with sufficient matching regardless of the fluctuations in the load impedance.

In other words, a first transformation effect belongs to a value tuple from the set of value tuples for which the transformation effect of the variable matching network has been measured in advance. The “second” transformation effect is that associated with any tuple of control signals occurring during the operation of the variable matching network Transformation effect. In general, this tuple will not be from the set, but can be appropriately approximated by a suitable tuple from the set. In this case, the second transformation effect is approximated by the transformation effect for the specific tuple or by suitable interpolation between such tuples and the transformation effects associated with the tuples. A tuple from the set that best approximates the second tuple can be selected as a certain tuple, or a new tuple that interpolates suitably between tuples from the set, in which case an interpolating new transformation effect would also have to be assigned to it. Starting from the input reflection of the variable matching network - which can be measured well in an environment of, for example, 50 ohms - and the approximation to the actual transformation effect of the variable matching network, an approximation to the input impedance of the welding press is determined, and from the approximation to the input impedance of the welding press and the approximation An estimate of the current power losses in the variable matching network can be obtained from the actual transformation effect.

With the help of this information it is possible to always select the control variables of the variable matching network, for example computer-controlled, so that the portion of the high-frequency power of the high-frequency source delivered to the welding press is maximized, and not just the portion of the reflected at the input of the variable matching network High frequency power of the high frequency source is minimized. Furthermore, the losses in the variable matching network can be controlled and thermal damage to the variable matching network can be avoided.

With the method according to the invention, a variable matching network has a fast regulating speed at which, at the same time, a global optimum of the mismatching is reliably achieved at the input of a variable matching network with a first number of control signals. The state of the art typically measures at most the high-frequency power emitted by the source, but mostly only the DC power consumed by the source, around that of the weld metal or Estimate the high-frequency power consumed by the welding source. With the method according to the invention, the power consumed by the weld metal or welding press is determined much more precisely than in the prior art. Application of the method according to the invention then allows a significantly more precise control of the weld.

In one embodiment, at least one of the impedances can be well below 50 ohms, so that one or more adapters are required that push the 50 ohms of your VNA sufficiently close to the desired impedances. For example, such an adapter can transform at an operating frequency of 50 ohms to 5 ohms (and, conversely, from 5 ohms to 50 ohms). Here, the transformation effect of the adapter must first be determined. This can be done through simulation. In a further embodiment, two adapters can be measured "back to back" (50R- 5R, 5R-50R) and then inserted between the two adapters (e.g.) 5-ohm lines of different lengths (50R-> 5R, line, 5R-> 50R). From the assumption of the symmetry of the adapter and the S-matrices determined with different lengths of the lines with the VNA, the S-matrix of the adapter can be inferred. In a further step, an arrangement, adapter 50R-> 5R, matching network (for example from 5R to 50R) ”with the VNA, with both sides being approximately 50R, is then measured. After this measurement, the effect of the adapter can be calculated, which is also called "de-embedding". In this way one can determine the transformation effect of a large number of meaningful matching networks (e.g. as S-matrices).

In one embodiment, the method comprises the further steps:

Choice of a first whole number n;

Choosing a minimum and a maximum for each control signal;

Selection of the first set of value tuples as a tuple of n equidistant values between the respective minimum and maximum of the respective control signal, the “first set” corresponding to the predefined value tuples of a number of control signals. The higher the number n is selected, the more precise the adjustment of the adaptation is, since the steps between the minimum and maximum are smaller. However, a suitable choice for n must be made here based on the circumstances (control, load, etc.), since more adjustment steps also take more time. The level of the respective control signal is meant as the minimum and maximum of each control signal. A computer-controlled search algorithm can find out, for example, a minimum and a maximum, ie a range of values for each control variable for optimal adaptation to the given load. These minima and maxima can be selected from the value tuple table. In this way, the amount of value tuples can be selected for the method according to the invention. This embodiment has the advantage that, for. B. a subsequent application can be carried out within an “optimal” minimum / maximum of the control signals. This enables the application to run in a particularly time-efficient manner. It also has the advantage that a particularly time-efficient process can protect sensitive semiconductor components in the high-frequency source.

In one embodiment, the method comprises the further steps:

Determination of a third value tuple from the number of control signals, or from the set of predefined value tuples, a number of control signals and a second transformation effect in such a way that the mismatch between the load impedance transformed by means of the second transformation effect and the source impedance among all value tuples from the set of value tuples adopts a minimum; and

Setting the control signals to the values given by the third value tuple. By using a model for the variable matching network, the mismatch can be minimized in one step, and an optimum mismatch is achieved immediately. The loss of signal power between the input and output of the variable matching network also follows from the transformation effect.

In an alternative embodiment, the method comprises the further steps:

Determination of a fourth value tuple from the first number of control signals or from the set of predefined value tuples Number of control signals and a second transformation effect such that the part of the power of the source signal delivered to the input of the load at the load impedance among all value tuples from the first set, or from the set of predefined value tuples one

Number of control signals assumes a maximum; and

Set the control signals to those given by the fourth value tuple

Values.

The variable matching network generally has losses. In the case of low losses in the variable matching network, the third and fourth value tuples do not differ significantly; the minimization of the mismatch to the source impedance and the maximization of the power delivered to the load take place with the same value tuples. With increasing losses in the matching network, this is no longer necessarily the case. If the power delivered to the load is to be maximized even with non-negligible losses in the variable matching network, this is advantageously achieved by this alternative embodiment.

In a preferred embodiment of the alternative embodiment, the method includes the further step of determining the power delivered to the load at the load impedance from the power of the source signal, the source impedance and the transformation effect of the variable matching network when the control signals are set to the values given by the fourth value tuple . In particular if the load represents a plasma for processing semiconductor wafers, the precise knowledge (and, based on this, control) of the power delivered to the load is of great importance. In the above embodiment, it is possible to determine the power delivered to the load more precisely than if this, as is customary in the prior art, is only approximated by the power of the source signal.

It goes without saying that the above-described embodiments or features thereof can also be combined with one another in any combinations that differ from the claims and their references in order to provide solutions to the above object within the scope of the present invention. Brief description of the figures

In addition, further features, effects and advantages of the present invention are explained with reference to the attached drawing and the following description. Components which at least essentially correspond in terms of their function in the individual figures are identified here with the same reference symbols, the components not having to be numbered and explained in all figures.

The drawing show:

Fig.l: a schematic representation of a variable capacitor system according to the invention;

2: a schematic representation of a matching network according to the invention;

3: a schematic representation of a system according to the invention; and FIG. 4: a schematic representation of a method according to the invention.

Working examples

Fig.l shows schematically the inventive variable capacitor system 1 for an impedance matching from a parallel or series connection of a variable transducer 11 with a capacitor 12 in Fig.la, the capacitor system 1 due to the variable transducer 11 acts like a variable capacitor according to Fig.lb . The capacitor 12 in the capacitor system 1 can be a capacitor with a fixed capacitance value or with a variable capacitance value, in the latter case the capacitor 12 is preferably designed as a vacuum capacitor or variable capacitor, the capacitor 12 and the transducer 11 then being arranged as a parallel circuit. The capacitor system 1 can furthermore comprise an electronic control device 13 which allows a capacitor value for the variable capacitor system 1 to be set at least by means of the variable transducer 11 for impedance matching. Here, the transducer 11 can be a Be high-performance high-frequency transducer. The transducer 11 can have a soft magnetic iron core, ferrite core, a ring core, a rod core, an EI core or a saturable ferromagnetic core.

2 schematically shows the matching network 4 according to the invention, comprising one or more variable capacitor systems 1 as an actuator for impedance matching. For this purpose, the matching network 4 can comprise one or more variable transducers 11 as variable actuators 41.

3 shows schematically the system 1 according to the invention comprising a signal source 2, a load 5, a directional coupler 3 and a variable matching network 4 according to the invention, the signal source 2 being connected to the load 5 via the directional coupler 3 and the variable matching network 4 for impedance matching.

4 schematically shows the method 100 according to the invention for regulating a variable matching network 4 according to the invention for impedance matching, comprising a measurement 110 of transformation matrices of the variable matching network 4 for a set of predefined value tuples of a number of control signals; a measurement 120 of an input impedance seen into the input of the matching network 4 for an arbitrary value tuple; determining 130 a predefined value tuple that best approximates the arbitrary value tuple from the set of predefined value tuples of a number of control signals and one of the predefined value tuples in accordance with the transformation matrices; and calculating 140 the load impedance on which the input impedance is based on the basis of the predefined value tuple, which approximates as best as possible, and of the associated transformation effect in accordance with one of the transformation matrices. Here, according to step 150, by selecting a first whole number n and selecting a minimum and a maximum for each control signal and selecting the set of predefined value tuples, a number of control signals can be performed as a tuple of n equidistant values between the respective minimum and maximum of the respective control signal become. Furthermore, the method can include the steps of determining 160 a third value tuple from the set of predefined value tuples of a number of control signals and a second transformation effect such that the mismatch between the load impedance transformed by means of the second transformation effect and the source impedance assumes a minimum among all value tuples from the set of value tuples; and setting 162 the control signals to the values given by the third value tuple. Alternatively, the method can include the further steps of determining 170 a fourth value tuple from the set of predefined value tuples of a number of control signals and a second transformation effect such that the part of the power of the source signal delivered to the input of the load at the load impedance among all value tuples from the Set of predefined value tuples of a number of control signals assumes a maximum; and setting 172 the control signals to the values given by the fourth value tuple. When setting the control signals to the values given by the fourth tuple of values, the further step of determining 180 the power delivered to the load at the load impedance from the power of the source signal, the source impedance and the transformation effect of the variable matching network 4 can take place.

At this point, it should be explicitly pointed out that features of the solutions described above or in the claims and / or figures can optionally also be combined in order to also be able to implement or achieve cumulatively explained features, effects and advantages.

It goes without saying that the exemplary embodiment explained above is only a first embodiment of the present invention. In this respect, the configuration of the invention is not limited to this exemplary embodiment. List of the reference symbols used

1 variable capacitor system according to the invention

11 transducer

12 capacitor

13 Control device

2 signal source

3 directional couplers

4 variable matching network according to the invention 41 actuators in the variable matching network

5 load

10 system according to the invention

100 Procedure for regulating a variable matching network for impedance matching

110-180 steps of the method according to the invention

Claims

Patent claims:

1. A variable capacitor system (1) for impedance matching from a parallel or series connection of a variable transducer (11) with a capacitor (12).

2. The variable capacitor system (1) according to claim 1, characterized in that the capacitor (12) is a capacitor with a fixed capacitance value.

3. The variable capacitor system (1) according to claim 1, characterized in that the capacitor (12) is a capacitor with a variable capacitance value, preferably the capacitor (12) is designed as a vacuum capacitor or variable capacitor.

4. The variable capacitor system (1) according to claim 2 or 3, characterized in that the capacitor (12) and the transducer (11) are arranged as a parallel circuit.

5. The variable capacitor system (1) according to any one of the preceding claims, characterized in that the capacitor system (1) further comprises an electronic control device (13) which allows a capacitor value for the variable capacitor system (1) at least by means of variable transducer (11) for impedance matching.

6. The variable capacitor system (1) according to any one of the preceding claims, characterized in that the transducer (11) is a high-performance high-frequency transductor.

7. The variable capacitor system (1) according to one of the preceding claims, characterized in that the transducer (11) has a soft magnetic iron core, ferrite core or a saturable ferromagnetic core.

7. The variable capacitor system (1) according to one of the preceding claims, characterized in that the transducer (11) has a ring core, a rod core or an EI core.

8. A variable matching network (4) for impedance matching comprising, as an actuator, one or more variable capacitor systems (1) according to one of the preceding claims.

9. A system (10) comprising a signal source (2), a load (5), a directional coupler (3) and a variable matching network (4) according to claim 8, wherein the signal source (2) via the directional coupler (3) and the variable matching network (4) is connected to the load (5) for impedance matching.

10. Use of one or more variable capacitors (1) of a matching network (4) according to claim 8 for impedance matching in a system (10) according to claim 9.

11. The method (100) for regulating a variable matching network (4) for impedance matching according to claim 8, comprising the following steps: V ennessen (110) of transformation matrices of the variable matching network (4) for a set of predefined value tuples of a number of control signals;

Measuring (120) an input impedance seen into the input of the matching network (4) for any value tuple;

Determining (130) a predefined value tuple that best approximates the arbitrary value tuple from the set of predefined value tuples of a number of control signals and one of the predefined value tuples according to the transformation matrices; and calculating (140) the load impedance on which the input impedance is based on the basis of the best possible approximating predefined value tuple and of the associated transformation effect according to one of the transformation matrices.

12. The method (100) according to claim 11, comprising the further steps (150):

Choice of a first whole number n;

Choosing a minimum and a maximum for each control signal; and selection of the set of predefined value tuples of a number of control signals as a tuple of n equidistant values between the respective minimum and maximum of the respective control signal.

13. The method (100) according to claim 11 or 12, comprising the further steps:

Determining (160) a third value tuple from the set of predefined value tuples of a number of control signals and a second transformation effect such that mismatch between the load impedance transformed by means of the second transformation effect and the source impedance assumes a minimum among all value tuples from the set of value tuples; and

Setting (162) the control signals to the values given by the third value tuple.

14. The method (100) according to claim 11 or 12, comprising the further steps:

Determination (170) of a fourth value tuple from the set of predefined value tuples of a number of control signals and a second transformation effect such that the part of the power of the source signal delivered to the input of the load at the load impedance among all value tuples from the set of predefined value tuples of a number of control signals assumes a maximum; and

Setting (172) the control signals to the values given by the fourth value tuple.

15. The method (100) according to claim 14, comprising the further step of determining (180) the power delivered to the load at the load impedance from the power of the source signal, the source impedance and the transformation effect of the variable matching network (4) when setting the control signals to the values given by the fourth value tuple.