Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
  • H03H7/002—Gyrators

Definitions

• the invention relates to a gyrator for AC signals.
• a gyrator is an electrical two-port device in which the voltage at the output is proportional to the current at the input, with the sign of the voltage changing when the input and output are reversed. If the current is an alternating current, it is thus converted either into an in-phase or into an opposite-phase alternating voltage, depending on which gate of the gyrator this current is presented.
• each gyrator is determined by its physical dimensions on a more or less narrow frequency band.
• a gyrator can also be realized as an active circuit comprising transistors and feedback-coupled operational amplifiers.
• a circuit requires a power supply and produces both noise and heat.
• a passive lower frequency gyrator is known in which the Faraday rotation in the ferrite is replaced by the planar Hall effect.
• both the coupling of the current into the Hall effect material and the tapping of the Hall voltage are hindered by high contact resistances, which impairs the efficiency of the gyrator.
• German Patent Application 10 2013 006 377.9 therefore pursues the approach of inductively coupling the Hall effect material to the outside world, in order to utilize the Hall effect and at the same time to avoid the losses due to contact resistance.
• fabrication is complex because of the complex, non-planar geometry, and inductive coupling requires highly permeable magnetic materials for low operating frequencies.
• a gyrator for AC signals has been developed.
• This includes a Hall effect material, means for enforcing this Hall effect material with a perpendicular to its plane or surface magnetic field, at least one input port for coupling an alternating current (I2) in the Hall effect material and at least one output port for decoupling an output voltage (U2; Ui) which is a measure of the Hall voltage generated by the injected alternating current.
• I2 alternating current
• Ui output voltage
• the Hall effect material may, for example, a gallium arsenide heterostructure, an electrically conductive monolayer / monolayer such as graphene or a other electrically conductive material in two dimensions. Its shape in the two dimensions in which it is conductive, in particular, can be round or nearly round. It is in principle subject to no restrictions. Ideally, it should be a topological body in the sense that it has a defined current direction for the input current in one spatial dimension and that a charge separation caused by the Hall effect can take place in another, ideally vertical spatial dimension.
• each gate is connected to a terminal electrode, which is electrically isolated from the Hall effect material and forms a capacitor with the Hall effect material.
• the alternating current is thus capacitively coupled into the Hall effect material, and the output voltage is capacitively decoupled from the Hall effect material.
• the capacitor advantageously has a capacity of at least 300 aF, preferably a capacity of at least 1 fF.
• connection electrode If only one terminal of a gate is connected to a connection electrode, the other connection may be connected to define a reference point for the input current or for the output voltage, for example outside the Hall effect material with a defined potential. If, in each case, only one connection is connected to a connection electrode by two or more gates, in particular all connections that are not connected to a connection electrode can be connected to the same defined potential outside the Hall effect material. They can then optionally be connected to each other.
• the insulation between the terminal electrodes and the Hall effect material may, for example, be a vacuum, an air gap or an insulating layer applied to the Hall effect material or applied around the Hall effect material.
• the Hall effect material may also be completely encapsulated in an insulating material.
• the terminal electrodes may be made of metal, doped semiconductors or other conductive materials without a large Hall effect.
• the connections between the terminals and the terminal electrodes and between the terminals and the outside world may be realized by conventional wires. It has been recognized that in the galvanic coupling of the Hall effect material to the prior art input and output ports, the direct contact of terminal electrodes with the Hall effect material imposed constraints that would have a local potential distribution unfavorable to efficiency Forcing Hall effect material. An electrically conductive terminal electrode forced the local potential in the entire area in which it applied directly to the Hall effect material to a common value. This compulsion abruptly ended at the edge of the connection electrode. In these peripheral areas, the potential in the Hall effect material made unsteady jumps. Even if the Hall effect material as such was perfect and had a Hall angle of approximately 90 degrees, locally energy was dissipated in the region of these jumps.
• the terminal electrode and the Hall effect material act as plates of a capacitor, a charge present on one of these two plates induces a corresponding polarization charge on the other plate. This is done according to the general rules of electrostatics, according to which
• Influence of a charge present on a plate on the other plate depends on continuous functions of the distance to this charge. Therefore, the constraints imposed by the potential distribution distribution electrode in the Hall effect material are not discontinuous from the outset. The occurrence of "hot spots", at which energy is dissipated, in the range of potential jumps can thus advantageously be reduced or even completely prevented.
• the capacitor specifies boundary conditions for the spatial distribution of the potential in the Hall effect material, which allow a continuous potential curve in the region of the Hall effect material, the edge of the connection electrode directly opposite.
• an output electrode is sufficient if the other terminal of the output gate is connected to a suitable reference point outside the Hall effect material. If the input gate and the output gate are reversed, the sign of the output voltage reverses so that it becomes in-phase with the input current.
• both terminals of the input port are each connected to a connection electrode (input electrode), wherein both input electrodes are electrically from
• Hall effect material are insulated and each form a capacitor with the Hall effect material. Then the alternating current between the two input electrodes can be driven by the Hall effect material. This gives the current a defined direction through the Hall effect material, which in turn determines the direction in which charge separation occurs.
• both terminals of the output gate are each connected to a terminal electrode (output electrode), wherein both output electrodes are electrically isolated from the Hall effect material and each form a capacitor with the Hall effect material. Then, the output voltage between both terminals of the output port corresponds to the voltage in the Hall effect material that drops between the two output electrodes. This output voltage is free from an external reference point and thus more meaningful.
• Both measures can be combined with one another, in particular in a particularly advantageous embodiment of the invention.
• a gyrator with three gates can be produced, for example, from the aforementioned embodiment with four connection electrodes, by connecting an input terminal and an output terminal to one another and as a terminal of the third gate be understood. This can optionally also be grounded.
• the operation of a three-gate gyrator is described on the assumption that it is a lossless "ideal" device (J. Shekel, Proceedings of the IRE 41 (8), 1014 (1953)) have this ideal characteristic when the Hall angle ⁇ of the Hall effect material is approximately 90 °.
• a gyrator with 3, 5 or 6 ports can also be used, for example, as a circulator.
• the gates can then be arranged in a cyclic order in such a way that an input current presented at a gate can be tapped at the next gate in the series as an in-phase output voltage, but at the previous gate in the series as an antiphase output voltage.
• the Hall effect material in at least two spatial dimensions has such an extent that it contains at least one million mobile electrons in both spatial dimensions along each of these spatial dimensions.
• the Hall effect and thus the action of the gyrator are almost fully established. If the dimensions of the material are further increased, only a comparatively slight increase can be achieved. Small structures are technically more difficult to manufacture than solid bodies, such as disks, from the Hall effect material. This requires less of the precious Hall effect material to make it.
• the Hall effect material may advantageously have an extension of at least 100 nm, preferably at least in at least two spatial dimensions
• Straight structures with a size of at least 1 ⁇ offer a particularly good compromise between material savings and complexity of production, since they can be manufactured with technically less demanding diffraction-limited lithography.
• connection electrode input electrode
• connection electrode output electrode
• c (s) For which range of frequencies co this boundary condition can be satisfied depends on the course of c (s).
• the c (s) most suitable for a range of desired operating frequencies co of the gyrator can be determined, for example, by parameter optimization or variational calculation.
• the solutions of the homogeneous case determine the qualitative behavior of the inhomogeneous case.
• Natural frequencies of the homogeneous case lead to poles in the inhomogeneous case in which the potential distribution becomes discontinuous and "hot spots" arise, in which energy is dissipated, corresponding to the frequencies at which the capacitively coupled Hall effect material magnetoplasmon resonances
• ⁇ for the gyrator
• the solutions of the differential equation are very benign in the sense that no impulses and therefore no energy-dissipating "hot spots" in the
• the Hall effect material is a quantum Hall effect material with a Hall angle ⁇ of 90 °
• the calculation of the together with Joule's heat as scalar product j (f) ⁇ VF (F) at each location F in the Hall effect material zero, since both vectors are always perpendicular to each other.
• the angle between the two vectors corresponds to the Hall angle ⁇ .
• the capacitance per length c (s) can be varied, for example, by varying the overlap of the connection electrode with the Hall effect material and / or the thickness and / or the dielectric constant of the insulation between connection electrode and Hall effect material. But it can also be varied in a further particularly advantageous embodiment of the invention for the duration of the gyrator.
• means are provided for acting on the insulating region between at least one connection electrode and the Hall effect material with an electric bias field, which changes the spatial distribution of the capacitance over the region of the connection electrode.
• the capacitor then advantageously contains a ferroelectric or a nonlinear dielectric as insulation between the terminal electrode and the Hall effect material.
• connection electrodes along an outer periphery of the Hall effect material are arranged to each other such that in opposite directions along this circumference of a connection electrode to the adjacent connection electrode respectively Paths whose lengths do not differ by more than 10%.
• the terminal electrodes are then distributed uniformly along the outer circumference of the Hall effect material. If, for example, the Hall effect material is in the form of a circular ring or circular disk, in the case of a gyrator with two input electrodes belonging to an input gate and two output electrodes belonging to one output gate, ie a total of four connection electrodes, the connection electrodes are each 90 ° along the circumference offset from each other.
• the outer circumference of the Hall effect material has a self-similar, in particular fractal, structure at least in a partial area in which one of the terminal electrodes forms a capacitor with it.
• a self-similar, in particular fractal, structure is one of the structures with the greatest length L, while at the same time minimizing material consumption, which can still be regarded topologically as one body, so that there exists a defined current direction and a direction for charge separation by the Hall effect ,
• connection electrode partially overlap a flat region of the Hall effect material, either on one side or on both sides, each spaced by a suitable insulation.
• connection electrode instead of a fractal structure, another highly tortuous structure may be used, such as an interdigitating structure as used for metal electrodes of thin film capacitors.
• the matrix Y 2 of the complex conductance is given by where y e is (co) even and y is 0 (co) odd functions of frequency ⁇ , ⁇ is the conductivity of the Hall material.
• ⁇ is the conductivity of the Hall material.
• a necessary prerequisite for this symmetrical form of the matrix ⁇ 2 ( ⁇ ) is that the capacitors formed by all the connecting electrodes, each with the Hall effect material, have the same capacitances. Therefore, in a particularly advantageous embodiment of the invention, the capacitors formed by all the connection electrodes each with the Hall effect material have capacitances which differ from one another by at most 10%.
• connection electrodes with the Hall effect material each form a capacitor whose capacitance is constant at least in sections.
• W is the length of the section on which the capacitance per unit length c (s) is constant
• c is the constant value of c (s) in this section.
• the value of ⁇ adjusts the impedance of the gyrator and, in particular, matches the devices or components of the outside world connected to the gates. As a rule, one strives to increase ⁇ to bring the impedance close to the standard impedance for high frequency applications of 50 ⁇ .
• the matrix is ⁇ 3 ( ⁇ ) of the complex conductance
• the prerequisite for the symmetrical shape of the matrix ⁇ 3 ( ⁇ ) is that the three gates are each connected to terminal electrodes, which together form equal capacitances with the Hall effect material. This can be achieved, for example, by connecting in each case one connection of one of the three gates to a connection electrode and all three connection electrodes forming equal capacities with the Hall effect material. Equal capacities for all three goals can also be achieved with four connection electrodes, two of which each have half the capacity of the Hall effect material as the other two. The two Terminal electrodes with half the capacity are then connected together and assigned to the same gate.
• the Hall effect material therefore forms a capacitor with at least one connection electrode along at least one outer circumference of at least 2%, preferably between 50% and 70%, of the length of this outer circumference.
• Hall effect material a capacitor. If the Hall effect material is present as a stacking of several such layers, for example in the form of slices, the gyratory effect, ie the amount of the proportionality constant between output voltage and input current, is advantageously increased and edge effects of the capacitor are reduced.
• the Hall effect material is a quantum Hall effect material.
• the Hall angle ⁇ by which the charge separation is tilted from the current direction through the material, is then approximately 90 °.
• some Hall effect materials without quantum Hall effect such as arsenic, antimony, bismuth, ⁇ -tin (gray tin), graphite and thin layers of doped semiconductors.
• quantum Hall effect materials such as arsenic, antimony, bismuth, ⁇ -tin (gray tin), graphite and thin layers of doped semiconductors.
• the Hall effect material has a Hall angle ⁇ as close as possible to 90 °, and requires the lowest possible magnetic field.
• the Hall properties should not suffer from the further processing steps to make the finished Gyrator device. It is advantageous if the Hall effect material is easily patternable and machinable and if multiple layers of this material can be easily connected in parallel to increase the capacitance of the capacitor.
• ⁇ is the conductivity having in two dimensions the unit ampere per volt.
• R e is an operator that rotates a vector through the angle ⁇ about an axis that is parallel to the magnetic field traversed by the Hall effect material and perpendicular to the plane in which the two-dimensional electron gas is movable , ü is any unit vector in this plane.
• E ⁇ 7) is the gradient of the potential field V (7). At the low frequencies of interest, the laws of electrostatics suffice to describe the fields inside the Hall effect material. V satisfies the Laplace equation
• the capacitive terminal electrodes provided according to the invention introduce along the outer circumference of the Hall effect material a local capacitance c (s) per unit length as a function of the location s on this outer circumference. In the area of Final electrodes is c (s) finite; in the gaps between the terminal electrodes, c (s) drops to zero. There is a general connection between the capacitance C of a capacitor and the charge Q stored on it
• FIG. 1 shows a simple embodiment of the gyrator according to the invention.
• the Hall effect material H is present here as a circular disk. Along the circumference of this circular disc, each offset by 90 ° to each other, four metallic terminal electrodes are arranged, which each form a capacitor with the Hall effect material H. Via two opposite input electrodes C A and C B , an alternating current I H is driven by the Hall effect material. Due to the Hall effect in conjunction with a magnetic field perpendicular to the plane of the drawing, an electric Hall field E H is generated which is perpendicular to the current direction. This leads to a charge separation in the field direction.
• the terminal electrode C is isolated by a dielectric D against the Hall effect material H.
• a voltage source S two auxiliary electrodes Fi and F 2 are now fed, between which a variable electric field is built up. With this field, ⁇ inside the dielectric D can be set to the desired value.
• FIG. 3 shows an exemplary embodiment of a gyrator according to the invention, in which the Hall effect material H has a fractal structure.
• the Hall effect material H surrounded completely by points surrounded by a dielectric forms analogously to FIG. 1 with the four connection electrodes C 1A , C 1 B , C 2 A and C 2 B one capacitor each.
• the fractal shape extends the outer circumference of the Hall effect material H without this taking up more space. It is a mold with minimal consumption of Hall effect material per unit length of outer circumference.
• FIG. 4 shows a further exemplary embodiment of a gyrator according to the invention, in which the Hall effect material H has a fractal structure.
• the material is composed of many small hexagons, whereby contact resistances between these hexagons are neglected.
• the Hall effect material H forms one capacitor each with the three connection electrodes Ci, C 2 and C 3 .
• the paths from one connection electrode to the other two (adjacent) connection electrodes are the same in each case; it is approximately of C 2 to C as far as C 2 to C. 3
• the holes in the structure of the Hall effect material H reduce the Material consumption, but the material is still a whole topological body.

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• 2013
  • 2013-11-29 DE DE102013018011.2A patent/DE102013018011B4/de not_active Expired - Fee Related
• 2014
  • 2014-10-31 JP JP2016534909A patent/JP6556131B2/ja not_active Expired - Fee Related
  • 2014-10-31 EP EP14812707.9A patent/EP3075073B1/de active Active
  • 2014-10-31 CN CN201480065070.3A patent/CN106416065B/zh not_active Expired - Fee Related
  • 2014-10-31 WO PCT/DE2014/000558 patent/WO2015078426A1/de not_active Ceased
  • 2014-10-31 US US15/037,201 patent/US9712129B2/en not_active Expired - Fee Related

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