Transmission line structure, antenna device comprising same, and method for producing a transmission line structure

Abstract

The invention relates, inter alia, to a transmission line structure comprising a ground plane and a conductor structure arranged above the ground plane. The conductor structure, together with the ground plane, forms at least part of a transmission line. The conductor structure comprises at least one inductive element in series with respect to the transmission line and, together with the ground plane, forms at least one capacitive element in parallel with respect to the transmission line. The conductor structure further comprises at least one capacitive element in series with respect to the transmission line and at least one inductive element in parallel with respect to the transmission line. The at least one inductive element in parallel with respect to the transmission line electrically interconnects the conductor structure and the ground plane. The at least one capacitive element in series with respect to the transmission line comprises two electrically conductive base layers and a dielectric layer. Either the base layers overlap at least in part and the dielectric layer is provided between the base layers or the at least one capacitive element in series with respect to the transmission line further comprises an electrically conductive cover layer arranged above the base layers, and the dielectric layer is provided between the base layers and the cover layer.

Description

[0001] Transmission line structure, antenna device comprising the same and method for producing a transmission line structure

[0002] Area

[0003] The invention relates to a transmission line structure, an antenna device comprising the transmission line structure and a method for producing a transmission line structure.

[0004] background

[0005] In electrical engineering, a transmission line is a structure for the wired transmission of electromagnetic waves. Transmission lines are used primarily in high-frequency technology, for example, in antennas or other (high-frequency) components such as filters, phase shifters, or transformers.

[0006] Antennas play an important role in various technical fields. An antenna can generally be understood as a technical device for transmitting and receiving electromagnetic waves, which converts conducted electromagnetic waves into free-space waves (transmitting antenna) and / or – conversely – electromagnetic waves arriving as free-space waves into conducted electromagnetic waves (receiving antenna).

[0007] The size of an antenna or a transmission line structure installed within it is related to the respective wavelength of electromagnetic waves to be transmitted and / or received by the antenna and is typically on the order of a quarter (monopole antenna) or half the wavelength (dipole antenna). At comparatively low frequencies (and thus comparatively long wavelengths), the size of an antenna is consequently comparatively large. For example, at a frequency of 600 MHz, the resulting (vacuum J) wavelength is 50 cm and consequently a size on the order of 25 cm (dipole antenna) or 12.5 cm (monopole antenna). Antennas with such a comparatively large size can be disadvantageous in applications where components with the smallest possible dimensions are typically desirable, such as in the automotive or mobile communications sectors.

[0008] The same applies (also) to other (high-frequency) components in which transmission line structures are used whose dimensions depend on a wavelength corresponding to a respective operating frequency.

[0009] Against this background, there is a need for transmission line structures and antennas with a reduced size. Furthermore, the transmission line structures and antennas should be as low-complexity and economically manufacturable as possible, as well as adaptable to frequency and / or size requirements (scalability), and compatible with existing (radio-frequency) components.

[0010] General description of some preferred embodiments

[0011] Based on this, it is an object of the present invention to provide a transmission line structure and an antenna device that have a reduced size, particularly with respect to a desired phase shift. Furthermore, the transmission line structure and the antenna device according to the invention should be as low-complexity and economical to manufacture as possible, be adaptable (scalable) to frequency and / or size requirements, and be compatible with existing (radio-frequency) components.

[0012] According to a first aspect of the present invention, this object is achieved by a transmission line structure according to claim 1. Preferred and advantageous embodiments of the transmission line structure are disclosed in the subclaims relating to the transmission line structure.

[0013] The transmission line structure according to the invention comprises a ground plane and a conductor structure arranged above the ground plane, which, together with the ground plane, forms at least part of a transmission line; wherein the conductor structure comprises at least one inductive element that is serial with respect to the transmission line and, together with the ground plane, forms at least one capacitive element that is parallel with respect to the transmission line; wherein the conductor structure further comprises at least one capacitive element that is serial with respect to the transmission line and at least one inductive element that is parallel with respect to the transmission line; wherein the at least one inductive element that is parallel with respect to the transmission line electrically connects the conductor structure and the ground plane to one another;and wherein the at least one capacitive element serial with respect to the transmission line comprises two electrically conductive base layers and a dielectric layer, wherein either;

[0014] • the base layers at least partially overlap and the dielectric layer is provided between the base layers, or

[0015] • the at least one capacitive element serial with respect to the transmission line further comprises an electrically conductive cover layer arranged over the base layers and the dielectric layer is provided between the base layers and the cover layer.

[0016] According to the first aspect of the present invention, a structure is provided in which a conductor structure, together with a ground plane, forms at least part of a transmission line. In preferred embodiments, the conductor structure and the ground plane together form a resonant transmission line structure. A resonant structure can be understood, for example, as a structure that behaves resonantly at at least one predetermined (operating) frequency, that is to say, for example, resonates. A conductor structure can be understood, for example, as an at least partially electrically conductive structure. In preferred embodiments, the conductor structure is therefore at least partially electrically conductive and / or the conductor structure comprises at least one at least partially electrically conductive element. An at least partially electrically conductive element can, for example, be a metal element (e.g.a metal section and / or a metal strip) and / or a wire element (e.g. a wire).

[0017] In preferred embodiments, the at least one electrically conductive element is an approximately perfect electrical conductor (PEC). An ideal electrical conductor can be understood, for example, as a theoretical / idealized material with infinite electrical conductivity or with zero electrical resistance. An approximately ideal electrical conductor can therefore be understood, for example, as a conductor with a comparatively very high electrical conductivity or a comparatively very low electrical resistance (e.g., silver, copper, gold, aluminum, etc.).

[0018] A wire element can be understood, for example, as a wire or a section of a wire. A wire can be understood, for example, as an at least partially flexible metal strand. A cross-section of a wire can be, for example, circular or polygonal, preferably quadrangular, and particularly preferably rectangular. In preferred embodiments, at least part of the conductor structure has a substantially flat shape.

[0019] A ground plane can be understood, for example, as an at least partially electrically conductive surface that is electrically connected to a ground potential, preferably zero ground potential. The ground plane can also be referred to, for example, as a ground plate and / or be formed as a metal plate. In preferred embodiments, the ground plane thus comprises a metal surface, the ground plane is at least partially electrically conductive, and / or the ground plane is electrically connected to a ground potential, preferably zero ground potential. In preferred embodiments, the ground plane is an approximately ideal electrical conductor.

[0020] A surface, in particular a metal or mass surface, can be understood, for example, as a substantially planar, in particular a metal or mass structure. In preferred embodiments, the mass surface therefore has a substantially planar shape. A substantially planar shape can be understood, for example, as meaning that the dimensions of the shape in two spatial directions are significantly larger than the dimensions of the shape in a third spatial direction. Significantly larger can mean, for example, at least a factor of 2 larger, preferably at least a factor of 5 larger, particularly preferably at least a factor of 10 larger.

[0021] A transmission line can be understood, for example, as a structure for the wired transmission of electromagnetic waves. For example, a transmission line can comprise a pair of conductors over which an electromagnetic field can be transmitted. In preferred embodiments, the ground plane and the conductor structure arranged above the ground plane form at least part of a pair of conductors over which an electromagnetic field can be transmitted.

[0022] The fact that the conductor structure is arranged above the ground plane can be understood, for example, to mean that the conductor structure is arranged at the top within the transmission line structure in a case in which the ground plane is arranged at the bottom within the transmission line structure. In preferred embodiments, the ground plane is therefore arranged at the bottom within the transmission line structure and / or the conductor structure is arranged at the top within the transmission line structure, in particular above the ground plane. In preferred embodiments, the conductor structure is therefore arranged at a distance from the ground plane. The conductor structure comprises at least one inductive element that is series with the transmission line and, together with the ground plane, forms at least one capacitive element that is parallel with the transmission line.

[0023] An inductive element that is serial with respect to a transmission line can be understood, for example, as an element that provides an inductance along a transmission direction of the transmission line. A serial inductive element can therefore be understood, for example, as an element that acts and / or appears as a serial inductance. In other words, an inductive element that is serial with respect to a transmission line can be understood, for example, as an element that is a part, in particular only, of one conductor of a conductor pair that forms the transmission line. In preferred embodiments, the at least one inductive element that is serial with respect to the transmission line is formed, preferably exclusively, as part of the conductor structure and / or along a transmission direction of the transmission line.In preferred embodiments, the inductive element which is serial with respect to the transmission line in particular does not connect the conductor structure and the ground plane to one another.

[0024] In preferred embodiments, the at least one inductive element connected in series with the transmission line comprises and / or corresponds to at least one at least partially electrically conductive element. In particularly preferred embodiments, the at least one inductive element connected in series with the transmission line comprises at least one substantially planar and / or rectangular metal element (e.g., a metal strip).

[0025] A capacitive element parallel to a transmission line can be understood, for example, as an element that provides a capacitance transverse to a transmission direction of the transmission line. A parallel capacitive element can therefore be understood, for example, as an element that acts and / or appears as a parallel capacitance. In other words, a capacitive element parallel to a transmission line can be understood, for example, as an element that provides a capacitance between the conductors of a conductor pair that forms the transmission line.In preferred embodiments, the at least one capacitive element parallel with respect to the transmission line is formed by the conductor structure and the ground plane and / or between the conductor structure and the ground plane and / or the at least one capacitive element parallel with respect to the transmission line is arranged transversely to a transmission direction of the transmission line.

[0026] In preferred embodiments, the at least one capacitive element parallel with respect to the transmission line comprises, corresponds to, and / or forms at least one capacitor. A capacitor can be understood, for example, as a device that stores electrical energy in an electric field, e.g., by accumulating electrical charge on two surfaces arranged close to one another and insulated from one another. In preferred embodiments, at least a portion of the conductor structure forms a first surface of a capacitor and / or at least a portion of the ground plane forms a second surface of the capacitor. In the case of the parallel capacitive element, the first and second surfaces of a capacitor formed in this way can be insulated from one another, for example, by a dielectric (e.g., air) arranged between the first and second surfaces.

[0027] A transmission line with series inductive and parallel capacitive elements can, for example, be referred to as a right-handed (RH) transmission line. In preferred embodiments, the at least part of a transmission line formed by the conductor structure together with the ground plane therefore comprises at least a part of a right-handed transmission line (RH-TL). In other words, in preferred embodiments, the conductor structure, together with the ground plane, forms at least a part of a right-handed transmission line.

[0028] Furthermore, the conductor structure encompassed by the transmission line structure comprises at least one capacitive element in series with respect to the transmission line and at least one inductive element in parallel with respect to the transmission line.

[0029] An inductive element that is parallel with respect to a transmission line can be understood, for example, as an element that provides an inductance transverse to a transmission direction of the transmission line. A parallel inductive element can therefore be understood, for example, as an element that acts and / or appears as a parallel inductance. In other words, an inductive element that is parallel with respect to a transmission line can be understood, for example, as an element that provides an inductance between the conductors of a conductor pair that forms the transmission line. In preferred embodiments, the at least one inductive element that is parallel with respect to the transmission line is therefore arranged transversely to a transmission direction of the transmission line and / or electrically connects the conductor structure and the ground plane to one another.

[0030] In preferred embodiments, the at least one inductive element parallel to the transmission line comprises at least one at least partially electrically conductive element. In particularly preferred embodiments, the at least one inductive element parallel to the transmission line comprises at least one wire element and / or at least one flat metal element with a rectangular cross-section (e.g., a metal strip).

[0031] A capacitive element that is serial with respect to a transmission line can be understood, for example, as an element that provides a capacitance along a transmission direction of the transmission line. A series capacitive element can therefore be understood, for example, as an element that acts and / or appears as a serial capacitance. In other words, a capacitive element that is serial with respect to a transmission line can be understood, for example, as an element that is a part, in particular only, of one conductor of a conductor pair that forms the transmission line. In preferred embodiments, the at least one capacitive element that is serial with respect to the transmission line is formed, preferably exclusively, as part of the conductor structure and / or along a transmission direction of the transmission line.

[0032] In preferred embodiments, the at least one capacitive element connected in series with the transmission line comprises, corresponds to, and / or forms at least one capacitor. In preferred embodiments, the two electrically conductive base layers and / or the electrically conductive cover layer form surfaces of at least one capacitor. The surfaces of this at least one capacitor can be insulated from one another, for example, by the dielectric layer. In particularly preferred embodiments, the electrically conductive base layers and / or the dielectric layer together form at least one capacitor.

[0033] In this case, either the base layers overlap at least partially and the dielectric layer is provided between the base layers, or the at least one capacitive element that is serial with respect to the transmission line further comprises an electrically conductive cover layer arranged above the base layers, and the dielectric layer is provided between the base layers and the cover layer. In preferred embodiments, the base layers and / or the cover layer are approximately ideal electrical conductors.

[0034] In preferred embodiments, the dielectric layer comprises a dielectric substrate. In particularly preferred embodiments, the dielectric layer comprises at least one plastic, for example, at least one polyimide, and / or the dielectric layer is provided, for example, as a polyimide film. Alternatively or additionally, the dielectric layer can comprise, for example, a thin, structured printed circuit board (PCB), a PTFE (polytetrafluoroethylene)-based dielectric, and / or other dielectric materials than those mentioned above.

[0035] A transmission line with series capacitive and parallel inductive elements can, for example, be referred to as a left-handed (LH) transmission line. In preferred embodiments, the at least one part of a transmission line formed by the conductor structure together with the ground plane further comprises at least a part of a left-handed transmission line (LH-TL). In other words, in preferred embodiments, the conductor structure, together with the ground plane, forms at least a part of a left-handed transmission line.

[0036] The conductor structure encompassed by the transmission line structure, together with the ground plane, forms at least part of a right-handed transmission line and at least part of a left-handed transmission line. Such a transmission line can be referred to, for example, as a composite right- / left-handed (CRLH) transmission line. In preferred embodiments, the transmission line is therefore a CRLH transmission line (CRLH-TL). The transmission line structure can therefore also be referred to as a CRLH transmission line structure.

[0037] A CRLH transmission line can also be referred to as a metamaterial, in particular a one-dimensional one. A metamaterial can be understood, for example, as a material that has properties that are rarely or never observed in naturally occurring materials. In particular, a metamaterial can be understood as an artificially produced structure whose permeability to electric and magnetic fields (permittivity or (magnetic) permeability) deviates from the permeability of naturally occurring (i.e., conventional) materials to such fields. This is the case with the transmission line structure according to the invention - as explained in more detail below - so that it can also be referred to, for example, as a metamaterial structure.

[0038] Because the transmission line structure according to the invention at least partially forms a composite right- / left-handed transmission line, it has electromagnetic properties which, at least for certain frequencies, advantageously enable a reduction in an electromagnetic wavelength in the transmission line structure or - conversely - a reduction in the required size of a component, in particular a high-frequency component, in which the transmission line structure is used and whose size depends on a given electromagnetic wavelength (for example, is intended to have resonant properties at this wavelength). This is made possible in particular by the fact that the structure according to the invention forms a composite right- / left-handed structure which has a permittivity and / or magnetic permeability that depends on a permittivity oradvantageously differs from the magnetic permeability of transmission line structures without such structures (which, for example, do not contain a metamaterial and / or do not form a CRLH structure). In this way, a desired phase shift (e.g., by 90°) can be achieved on a significantly shorter section of the transmission line structure, as may be required, for example, for a monopole resonance of a monopole antenna.

[0039] In preferred embodiments, a size, in particular a length, of the transmission line structure according to the invention is therefore at least a factor of 1.5, preferably at least a factor of 1.75, particularly preferably at least a factor of 2 smaller than a size of transmission line structures without CRLH elements. By virtue of the transmission line structure according to the invention having a reduced size, in particular at at least one predetermined resonant frequency, the transmission line structure enables the provision of high-frequency components (in which the transmission line structure is installed) with a likewise reduced size. High-frequency components (e.g., antennas) with a reduced size are particularly desirable in the automotive and / or mobile communications sectors (e.g., in mobile phones). The reduced size can advantageously reduce the space or room required by the transmission line structure.

[0040] In preferred embodiments, the transmission line structure is a transmission line structure for and / or for use in a, preferably wavelength-dependent, high-frequency component. A, particularly wavelength-dependent, high-frequency component can be understood, for example, as an antenna, preferably a monopole or dipole antenna, a filter, a phase shifter, and / or a transformer.

[0041] The transmission line structure according to the invention also has a comparatively low complexity and can be manufactured economically (as is often required in the automotive sector, for example). In particular, at least parts of the conductor structure and / or the ground plane can be produced using economical

[0042] Manufacturing processes, e.g., using a punching and / or bending process (also known as a punching and bending process or punching and bending technology), can be used. Furthermore, the reduced size allows for advantageous material savings.

[0043] Furthermore, it has been shown that the transmission line structure according to the invention is advantageously scalable due to its design, thus adaptable to frequency and / or size requirements. In particular (but not only) the capacitive and / or parallel inductive elements of a transmission line structure according to the invention, which are serial with respect to the transmission line, can be adapted in their dimensions to desired frequencies, in particular comparatively low (e.g., mobile radio frequencies) (e.g., between approximately 600 MHz and 1 GHz).

[0044] Finally, the transmission line structure according to the invention is compatible with existing components, in particular since the ground plane is (still) suitable for use in existing structures and / or components.

[0045] In preferred embodiments, the conductor structure comprises a layered structure. In preferred embodiments, the layered structure together with the at least one inductive element that is parallel with the transmission line forms the conductor structure. In other words, in preferred embodiments, the conductor structure consists of the layered structure and the at least one inductive element that is parallel with the transmission line. A layered structure can be understood, for example, as a structure that comprises and / or consists of one or more layers. In preferred embodiments, the layered structure comprises the electrically conductive base layers, the dielectric layer, the cover layer and / or the at least one inductive element that is series with the transmission line and / or consists of these layers and / or elements.Furthermore, in preferred embodiments, at least a portion of the layer structure, together with the ground plane, forms the at least one capacitive element parallel to the transmission line. In preferred embodiments, the layer structure has a substantially flat shape. Such a layer structure is particularly economical to manufacture and also particularly scalable.

[0046] In preferred embodiments, the ground plane and the conductor structure arranged above the ground plane form at least part of a microstrip line. A microstrip line can be understood, for example, as a transmission line consisting of a first, at least partially electrically conductive structure separated from a second, at least partially electrically conductive structure by a dielectric medium. The first and second, at least partially electrically conductive structures can, for example, have a substantially planar shape.

[0047] In preferred embodiments, the ground plane is flat or curved. This allows for improved geometric adaptability, for example, to existing or additional components, particularly high-frequency components. Whether the ground plane is flat or curved can therefore depend, for example, on the installation situation, particularly the mechanical one.

[0048] In preferred embodiments, the transmission line structure itself (likewise) forms a conductor structure. The conductor structure encompassed by the transmission line structure can thus be understood, for example, as an inner conductor structure, while the transmission line structure (itself) can be understood, for example, as an outer conductor structure that encompasses and / or is formed by the inner conductor structure and the ground plane. In preferred embodiments, the conductor structure arranged above the ground plane is therefore an inner conductor structure and / or the transmission line structure is an outer conductor structure.

[0049] In preferred embodiments, the transmission line structure further comprises a dielectric interlayer arranged between the ground plane and the conductor structure, which dielectric interlayer preferably consists at least partially of air and / or only partially of a solid. In other words, in preferred embodiments, the dielectric interlayer consists at least not only of a solid, for example, in the form of a dielectric substrate.

[0050] The dielectric intermediate layer can also comprise a solid, for example in the form of a dielectric substrate. The dielectric substrate and / or the solid can comprise and / or correspond to, for example, polyimide, polyethylene, PTFE (polytetrafluoroethylene), ceramic (e.g., steatite, aluminum oxide), and / or mica. For example, the dielectric intermediate layer can be designed as a mechanical support body (e.g., in the form of a plastic injection-molded part) on which the conductor structure rests, spaced from the ground plane. Alternatively or additionally, the dielectric intermediate layer can further comprise, for example, or consist of a material having a permeability number that is greater, preferably significantly greater, than 1, particularly in the high-frequency range.A permeability number significantly greater than 1 can, for example, be understood as a permeability number that is more than 5% greater than 1.

[0051] In particularly preferred embodiments, however, the intermediate layer consists predominantly of air and / or the intermediate layer at least not exclusively of a solid and / or a dielectric substrate. In other words, in preferred embodiments, the transmission line structure is not only designed as a printed circuit board, or the transmission line structure is not realized solely in the form of a printed circuit board, in particular a structured one. A printed circuit board (PCB) can be understood, for example, as a carrier for electronic components that contains, among other things, insulating layers made of a non-conductive substrate (e.g., a solid).

[0052] It has been shown that transmission line structures with an intermediate layer that consists at least partially of air and / or only partially of a solid material are particularly low in complexity and can be manufactured particularly economically (for example by means of a punching and / or bending process). In particular, the production of such structures requires less (or no) dielectric substrate and (also) no further processing of the substrate. For example, in a transmission line structure with an intermediate layer that consists predominantly of air, both a printed circuit board and the provision of electrical vias for connecting conductive layers of the printed circuit board can be dispensed with. Furthermore, it has been shown that such transmission line structures are particularly suitable for use in high-frequency components (such as, for example,Antennas) are advantageous because they have improved radiation characteristics.

[0053] In preferred embodiments, the dielectric intermediate layer is preferably arranged directly above and / or on the ground plane and / or, preferably directly below the conductor structure. In preferred embodiments, the conductor structure is furthermore preferably arranged directly above and / or on the intermediate layer. An arrangement of a first surface, layer or structure directly above / on / below a second surface, layer or structure can be understood, for example, that the first surface, layer or structure is arranged above / on / below the second surface, layer or structure in such a way that the first surface, layer or structure is in contact with the second surface, layer or structure and / or rests against the second surface, layer or structure.

[0054] In other words, in preferred embodiments, a space between the conductor structure and the ground plane is substantially filled with a dielectric (e.g., air and / or a dielectric material) or there is substantially a vacuum in this space.

[0055] In preferred embodiments, the at least one inductive element which is serial with respect to the transmission line is formed at least in sections as a planar conductor section and / or the conductor structure comprises at least one planar conductor section which, together with the ground surface, forms the at least one capacitive element which is parallel with respect to the transmission line.

[0056] In other words, in preferred embodiments, the at least one inductive element which is serial with respect to the transmission line is formed at least in sections as a conductor section with a substantially planar shape and / or the conductor structure comprises at least one conductor section with a substantially planar shape, which preferably together with at least a section of the ground plane forms the at least one capacitive element which is parallel with respect to the transmission line (e.g. in the form of a capacitor).

[0057] The planar conductor section or the conductor section with a substantially planar shape can, for example, comprise and / or correspond to at least one substantially planar and / or rectangular-shaped metal element (e.g., a metal strip). In particular, such planar sections / elements / structures exhibit comparatively low manufacturing complexity and are therefore particularly economical to produce (e.g., by means of a punching and / or bending process).

[0058] In preferred embodiments, the at least one inductive element parallel to the transmission line is arranged at a respective edge of the at least one planar conductor section. In other words, in preferred embodiments, a region in which the at least one inductive element parallel to the transmission line borders and / or is connected to the at least one planar conductor section is not located within a surface formed by the at least one planar conductor section (as is the case, for example, with so-called vias for connecting conductive layers of a printed circuit board).

[0059] Instead, in preferred embodiments, said region is located at the edge of and / or, preferably directly adjacent to said surface. An edge can be understood, for example, as an outer section of the at least one planar conductor section, i.e., for example, the outer 30%, preferably the outer 20%, particularly preferably the outer 10% of the surface formed by the at least one planar conductor section, in particular with respect to a width and / or length of this surface. In particularly preferred embodiments, the at least one inductive element parallel with respect to the transmission line is arranged directly and / or laterally at the respective edge. A lateral arrangement can be understood, for example, as an arrangement lateral or transverse to a longitudinal direction (e.g., the direction of a primary spatial extent) of the at least one planar conductor section.

[0060] It has been shown that arranging the at least one parallel inductive element at an edge of the at least one planar conductor section, preferably laterally and / or directly at the edge, contributes to particularly low complexity and cost-effective manufacturability of the transmission line structure. In particular, this eliminates the need for substrate processing (e.g., by providing vias), and enables cost-effective production, for example, by means of a punching and / or bending process.

[0061] In preferred embodiments, the at least one inductive element parallel with the transmission line has one or more bent, curved and / or kinked sections. In other words, in preferred embodiments, the at least one inductive element parallel with the transmission line is bent, curved and / or kinked at least in sections. A bent, curved or kinked section can be understood, for example, as a section that has at least one bend, curvature or at least one kink. A bend / curvature can be understood, for example, as an arc-shaped deviation from a direction, in particular a straight direction, or from a course, in particular a straight course. A kink can be referred to, for example, as a point at which something is sharply angled and / or bent, in particular from a straight course.

[0062] Alternatively or additionally, the at least one in relation to the

[0063] In preferred embodiments, the inductive element parallel to a transmission line has one or more straight, L-shaped and / or meandering sections. A straight section can be understood, for example, as a section that has no bend, no curvature and no kink. An L-shaped section can be understood, for example, as a section that has an L-shape at least from one viewing direction. An L-shape can, for example, comprise two elongated sections that form a substantially right angle, in particular an angle that is substantially 90°, for example neglecting manufacturing tolerances. An L-shaped section can, for example, (also) be referred to as a jib-shaped section. An L-shaped section can be understood as a preferred embodiment of a kinked section.A meandering section can be understood, for example, as a section that comprises and / or consists of several, preferably closely spaced, turns, loops, and / or kinks. A meandering section can be understood as a preferred embodiment of a bent, curved, and / or kinked section, particularly depending on whether the turns and / or loops are bent, curved, and / or kinked.

[0064] It has been shown that parallel inductive elements with one or more bent, curved, and / or kinked sections, in particular with one or more L-shaped and / or meandering sections, enable a further reduction in the overall size, in particular in the overall height, of the transmission line structure. This is because the provision of parallel inductive elements with bends, curvatures, and / or kinks, in particular in an L-shape and / or meandering, allows an overall length required for a respective electromagnetic wavelength to be provided in a spatially advantageous manner, namely with a comparatively low overall height. Furthermore, bends, curvatures, and / or kinks, preferably in an L-shape and / or meandering form, can be produced economically, for example by means of a punching and / or bending process.In preferred embodiments, the at least one inductive element that is series with the transmission line, the at least one inductive element that is parallel with the transmission line, and / or the ground plane are formed in one piece. In other words, in preferred embodiments, the at least one inductive element that is parallel with the transmission line is formed in one piece with the at least one inductive element that is series with the transmission line and / or with the ground plane. The aforementioned elements and / or the ground plane are formed in one piece, for example, if the conductor structure or the transmission line structure (which comprises the aforementioned elements and / or the ground plane) was produced exclusively by means of primary shaping, forming and / or separating and / or not by joining. In preferred embodiments, the conductor structure and / or the transmission line structure therefore do not comprise a joined (e.g.B. glued, welded and / or soldered) section for joining the aforementioned elements.

[0065] Transmission line structures with integrally formed elements and / or ground planes exhibit particularly low manufacturing complexity, particularly since no joining step(s) is / are required, and can therefore be manufactured particularly cost-effectively, for example, using a punching and / or bending process (respective examples of a separating or forming process). Furthermore, such transmission line structures have proven particularly robust due to the absence of joints. Avoiding joints is particularly desirable in the automotive sector, as joints age comparatively quickly, especially under stress due to varying thermal conditions, and can therefore be prone to failure.

[0066] In preferred embodiments, the at least one inductive element arranged parallel with respect to the transmission line comprises at least two inductive elements arranged symmetrically with respect to the conductor structure. In other words, in preferred embodiments, the conductor structure has at least two symmetrically arranged inductive elements that electrically connect the conductor structure and the ground plane. In preferred embodiments, each of the two symmetrically arranged inductive elements provides a double inductance 2LL, so that the two symmetrically arranged inductive elements, in particular when connected in parallel, provide a total inductance LL.It has been found that transmission line structures with such symmetrically arranged inductive elements, in particular, exhibit (even) further improved structural stability, since any forces acting on the transmission line structure (e.g., during assembly) are distributed even more effectively in this way. Furthermore, transmission line structures with symmetrically arranged inductive elements, in particular, exhibit an advantageous, particularly symmetrical distribution of the electromagnetic fields.

[0067] In preferred embodiments, the at least one inductive element that is serial with respect to the transmission line, the at least one capacitive element that is parallel with respect to the transmission line, the at least one capacitive element that is serial with respect to the transmission line and the at least one inductive element that is parallel with respect to the transmission line together form at least one CRLH cell, which together with the ground plane forms at least in sections a CRLH transmission line.

[0068] In preferred embodiments, an inductive element in series with respect to the transmission line, a capacitive element in parallel with respect to the transmission line, a capacitive element in series with respect to the transmission line and an inductive element in parallel with respect to the transmission line together form exactly one CRLH cell.

[0069] In preferred embodiments, the at least one CRLH cell comprises precisely one CRLH cell. Such embodiments are particularly advantageous with regard to reducing the overall size, in particular the overall length, since they enable a particularly short implementation of the transmission line structure according to the invention. In preferred embodiments, the at least one CRLH cell comprises and / or corresponds to at least one CRLH unit cell. A unit cell (also referred to as an elementary cell) can be understood, for example, as a repeating basic unit from which larger cells (e.g., the crystal lattice of a solid-state material) are constructed. Analogous to this understanding, the at least one CRLH unit cell in preferred embodiments is a repeating basic unit which, together with the ground plane, forms a, preferably one-dimensional, metamaterial.In preferred embodiments, at least a portion of the at least one CRLH unit cell is arranged periodically, in particular regularly and / or at equal intervals from one another, within the conductor structure. In preferred embodiments, each of the at least one CRLH unit cell is arranged substantially flat in the same plane and / or adjacent to one another. The conductor structure can, for example, comprise one, two, three, four, or more CRLH unit cells.

[0070] Alternatively or additionally, in preferred embodiments, the at least one CRLH cell comprises at least one CRLH cell with dimensions that differ from the dimensions of at least one further one of the at least one CRLH cell. In other words, in preferred embodiments, the at least one CRLH cell comprises at least one CRLH cell with variable dimensions and / or, in preferred embodiments, at least one of the at least one CRLH cell is not a CRLH unit cell. In preferred embodiments, furthermore, at least a portion of the at least one CRLH cell is not arranged periodically within the conductor structure. In other words, according to preferred embodiments, a targeted deviation is made from a periodic arrangement and / or from uniform dimensions of the at least one CRLH cell in order to achieve certain desired electromagnetic properties of the conductor structure, and thus of the transmission line structure.Thus, CRLH cells with dimensions that differ from the dimensions of a CRLH unit cell are particularly advantageous for taking so-called fringing fields into account in a resonant design of the transmission line structure, since such fringing fields lead to a change in the length required for resonance of at least one section of the conductor structure. Providing at least one CRLH cell with dimensions that differ from the dimensions of at least one other of the at least one CRLH cell, in particular at least one CRLH unit cell, therefore advantageously makes it possible to take such fringing fields into account, thereby achieving improved resonance properties of the transmission line structure.

[0071] Furthermore, it has been shown that providing at least one CRLH cell with variable dimensions, thus deviating from the uniformity of the at least one CRLH cell, enables a stepped impedance of the transmission line structure. Such a stepped impedance can advantageously increase the bandwidth of the transmission line structure.

[0072] In preferred embodiments, the conductor structure further comprises at least one exclusively right-handed conductor section, which, together with the ground plane, forms, at least in sections, an exclusively right-handed transmission line. In other words, in preferred embodiments, the transmission line structure comprises both at least part of a composite right-handed / left-handed (CRLH) transmission line and at least part of an exclusively right-handed (RH) transmission line. In preferred embodiments, the conductor structure comprises exactly one or exactly two exclusively right-handed conductor sections, so that the transmission line structure comprises exactly one or exactly two exclusively right-handed transmission lines or parts thereof.

[0073] An exclusively right-handed transmission line can be understood, for example, as a transmission line with only serial inductive or parallel capacitive elements (as is the case with a conventional microstrip line, for example). Alternatively or additionally, an exclusively right-handed transmission line can be understood, for example, as a transmission line without parallel inductive or serial capacitive elements (as is also the case with a conventional microstrip line, for example).

[0074] In preferred embodiments, the at least one exclusively right-handed conductor section therefore comprises inductive elements that are exclusively serial with respect to the transmission line and / or, together with the ground plane, forms capacitive elements that are exclusively parallel with respect to the transmission line. Alternatively or additionally, the at least one exclusively right-handed conductor section does not comprise an inductive element that is parallel with respect to the transmission line and / or a capacitive element that is serial with respect to the transmission line.

[0075] The combination of a CRLH transmission line with an RH transmission line advantageously enables dual mode operation of the transmission line structure with a higher operating frequency as the fundamental frequency and a lower operating frequency as the higher order resonant frequency.

[0076] In preferred embodiments, at least one virtual ground element is provided on the ground plane, via which the at least one inductive element parallel with respect to the transmission line electrically connects the conductor structure and the ground plane. A virtual ground element can be understood, for example, as a point in an electrical circuit that has a ground potential despite flowing electrical currents, but is not itself electrically connected, in particular directly, to a ground, in particular via a so-called galvanic contact. In preferred embodiments, the virtual ground element is thus configured to maintain a constant potential despite flowing electrical currents.In preferred embodiments, the virtual ground element comprises an electrically conductive layer, which is preferably designed as an approximately ideal electrical conductor, and at least one dielectric layer arranged between the ground surface and the electrically conductive layer. Preferably, the at least one inductive element parallel to the transmission line is electrically connected to the electrically conductive layer. The dielectric layer can, for example, have a material-dependent permittivity e. r have.

[0077] The provision of at least one virtual ground element makes it possible to dispense with the need to solder the at least one inductive element parallel to the transmission line to the ground plane. This advantageously provides a more robust transmission line structure that can also be manufactured economically, in particular without soldering.

[0078] In preferred embodiments, the transmission line structure further comprises at least one further conductor structure arranged above the ground plane, which together with the ground plane forms at least a part of at least one further transmission line, wherein the at least one further conductor structure is arranged substantially perpendicular and / or substantially parallel to the conductor structure, wherein preferably a part of the conductor structure simultaneously forms a part of the at least one further conductor structure. In other words, the (first) conductor structure and the at least one further conductor structure in preferred embodiments form at least in sections substantially a right angle to one another and / or run at least in sections substantially parallel to one another, thus together forming, for example, a substantially L-shaped, L-shaped or U-shaped structure.In particular, such L-shaped, 11-shaped, or U-shaped transmission line structures advantageously enable dual-frequency operation. Furthermore, since a part of the (first) conductor structure preferably simultaneously forms part of the at least one further conductor structure, a particularly compact design is achieved. In preferred embodiments, each of the CRLH (unit) cells is divided into two or more CRLH cells, whereby a coverable bandwidth of the transmission line structure can advantageously be (even) further increased. In preferred embodiments, therefore, at least one of the at least one CRLH cell comprises at least two CRLH sub-cells. For example, the at least one of the at least one CRLH cell can comprise two CRLH half-cells, three CRLH third-cells, four CRLH quarter-cells, etc. A half-cell, third-cell, quarter-cell, etc.For example, a CRLH cell can be understood as having a width of one half, one third, one quarter, etc. of the width of a CRLH (unit) cell.

[0079] In preferred embodiments, the transmission line structure further comprises at least one short-circuit connection element for establishing a short-circuit connection between the conductor structure and the ground plane. A short-circuit connection can be understood, for example, as an electrical connection that is completely or almost completely resistance-free. An electromagnetic resonance can advantageously develop between the short-circuit connection and an open end or open edge of the conductor structure (e.g. a λ / 4 resonance; with the electromagnetic wavelength λ). In other words, in preferred embodiments, the short-circuit connection and the open end or the open edge form reflective terminations of the transmission line structure, by which the transmission line structure is delimited, such that an electromagnetic resonance develops between these reflective terminations. An open end orAn open edge of a conductor structure can be understood, for example, as a section of the conductor structure that is preferably directly adjacent to a dielectric medium, preferably air. Such an open end / edge can, for example, receive and / or emit electromagnetic radiation.

[0080] In preferred embodiments, the short-circuit connection element is arranged at an end section of the conductor structure with respect to a longitudinal axis of the conductor structure, and the short-circuit connection element establishes the short-circuit connection between the end section of the conductor structure and the ground plane. In other words, in preferred embodiments, the short-circuit connection element is arranged, for example, at a head piece of the conductor structure and electrically connects it to the ground plane. By arranging the short-circuit connection element at an end section of the conductor structure, the entire length of the conductor structure is utilized, whereby the conductor structure—and thus the transmission line structure—can advantageously have an even further reduced size.

[0081] In preferred embodiments, the conductor structure has at least one section for receiving and / or emitting electromagnetic radiation. In preferred embodiments, the at least one section for receiving and / or emitting electromagnetic radiation is formed as an open end of the conductor structure.

[0082] The aforementioned object(s) are further achieved by the further aspects of the present invention.

[0083] A second aspect of the present invention relates to an antenna device, in particular a PIF antenna device, comprising a transmission line structure according to the first aspect. An antenna device can, for example, comprise and / or correspond to an antenna. An antenna can be understood, for example, as a device for emitting and / or receiving electromagnetic waves. A PIF antenna device can, for example, be referred to as a P1FA (Planar Inverted F Antenna, P1FA). Thus, the PIF antenna device according to preferred embodiments of the second aspect, comprising a (CRLH) transmission line structure according to the first aspect, can, for example, be referred to as a (CRLH) PIFA.Considering that the (CRLH) transmission line structure according to the first aspect can be referred to, for example, as a metamaterial structure, the PIF antenna device according to preferred embodiments of the second aspect can further be referred to, for example, as a metamaterial-based P1FA.

[0084] A P1FA can, for example, be understood to mean a specific type of so-called stripline or patch antenna. In preferred embodiments, the P1F antenna device therefore comprises and / or corresponds to a stripline and / or patch antenna. A stripline and / or patch antenna can, for example, comprise a first, smaller metal plate (which can, for example, form part of a conductor structure) arranged above a second, larger metal plate (which can, for example, form a ground plane). Together, the two metal plates of a stripline or patch antenna can form a resonant transmission line structure. Analogously, in preferred embodiments, the transmission line structure according to the first aspect (comprising a conductor structure and a ground plane) forms a resonant part of a (P1F) antenna device.

[0085] As already explained above, since the transmission line structure according to the first aspect, due to its special electromagnetic properties, causes a reduction in the electromagnetic wavelength in the transmission line structure, - conversely - a reduction in the size of the transmission line structure according to the first aspect is possible.

[0086] As a result, the antenna device according to the second aspect, which comprises a transmission line structure according to the first aspect, has a significantly reduced size compared to antennas without a CRLH structure, thus enabling the provision of a significantly reduced antenna, which is particularly (but not only) advantageous for applications in the automotive / mobile communications sector or at low frequencies (e.g., between 600 MHz and 1 GHz).

[0087] In preferred embodiments, the antenna device according to the second aspect further comprises a feed line to which the conductor structure and / or the ground plane can be connected and / or are connected. A feed line (also referred to as an antenna feed line or antenna feed) can be understood, for example, as an electrical conductor system that connects a transmitter and / or receiver to an antenna device. In preferred embodiments, the feed line is therefore configured to connect the antenna device, preferably the conductor structure and / or the ground plane, to a transmitter and / or a receiver.

[0088] A third aspect of the present invention relates to a method for producing a transmission line structure, in particular a transmission line structure according to the first aspect, the method comprising: providing a ground plane; and providing a conductor structure arranged above the ground plane, which together with the ground plane forms at least part of a transmission line; wherein the conductor structure comprises at least one inductive element that is in series with the transmission line, at least one capacitive element that is in series with the transmission line, and at least one inductive element that is parallel with the transmission line, and wherein the conductor structure, together with the ground plane, further forms at least one capacitive element that is parallel with the transmission line.wherein the at least one inductive element, parallel with respect to the transmission line, electrically connects the conductor structure and the ground plane; and wherein the at least one capacitive element, series with respect to the transmission line, comprises two electrically conductive base layers and a dielectric layer, wherein either;

[0089] • the base layers at least partially overlap and the dielectric layer is provided between the base layers, or

[0090] • the at least one capacitive element in series with the transmission line further comprises an electrically conductive cover layer arranged above the base layers, and the dielectric layer is provided between the base layers and the cover layer. According to the third aspect of the present invention, a method for producing a transmission line structure is provided, with which, in particular, a transmission line structure according to the first aspect can be produced.

[0091] In preferred embodiments, the method, in particular the provision of the conductor structure, comprises one or more steps of a punching and / or bending process. In other words, in preferred embodiments, the provision of the conductor structure in particular comprises one or more steps of a punching and / or bending process, wherein alternatively or additionally, the provision of the ground plane may (also) comprise one or more such steps. In preferred embodiments, at least the conductor structure is thus produced using one or more such steps.

[0092] A punching process can be understood, for example, as a separation process for producing at least one substantially flat component from at least one material (e.g., sheet metal, cardboard, etc.), for example, using at least one punching press and / or at least one cutting tool. A punching process can, for example, comprise at least one punching step.

[0093] A bending process can be understood, for example, as a forming process for forming at least one formable material (e.g., sheet metal) along an axis, for example, into a V-, U-, or channel shape. A bending process can, for example, comprise at least one bending step.

[0094] It has been found that producing a transmission line structure using one or more steps of a punching and / or bending process is comparatively low in complexity and particularly economical. Thus, a transmission line structure that is produced, in particular exclusively, using one or more steps of a punching and / or bending process can advantageously be produced without joining processes (e.g., welding, soldering, etc.). Alternatively, but in particular in addition to the one or more steps of a punching and / or bending process, the process can further comprise, for example, one or more steps of at least one further manufacturing process (e.g., a milling process, a welding process, a drilling process, a deep-drawing process, an embossing process, a coating process, etc.).

[0095] The preferred embodiments described above in this description should also be understood as being disclosed in all combinations with one another. In particular, preferred embodiments should be understood as being disclosed with respect to the different aspects. In particular, the preceding or following description of method steps according to preferred embodiments of the method for producing a transmission line structure should also disclose corresponding features of preferred embodiments of the transmission line structure. Likewise, the preceding or following description of features of preferred embodiments of the transmission line structure should also disclose corresponding method steps of preferred embodiments of the method for producing a transmission line structure.

[0096] Further advantageous preferred embodiments can be found in the following detailed description of some preferred embodiments, particularly in conjunction with the figures. However, the figures are intended only for the purpose of clarification and not to determine the scope of protection. The figures are not to scale and are intended merely to reflect the general concept by way of example. In particular, features contained in the figures should in no way be considered a necessary component. Brief description of the figures

[0097] The invention is explained in more detail below with reference to some drawings. They show:

[0098] Fig. 1a-lc show schematic perspective views (Fig. 1a, 1b) and a schematic side view (Fig. 1c) of an exemplary PIF antenna;

[0099] Fig. 2a, 2b are schematic representations of respective circuit diagrams of an exemplary exclusively right-handed transmission line (Fig. 2a) and an exemplary CRLH transmission line (Fig. 2b);

[0100] Fig. 3 is a schematic representation of a dispersion relation of an exemplary CRLH transmission line;

[0101] Fig. 4a is a schematic perspective view of an embodiment of a transmission line structure according to the invention;

[0102] Fig. 4b is a schematic representation of a circuit diagram of the embodiment according to Fig. 4a;

[0103] Fig. 5a, 5b a schematic side view (Fig. 5a) and a schematic representation of a circuit diagram (Fig. 5b) of an exemplary series capacitive element;

[0104] Fig. 5c is a schematic side view of another exemplary series capacitive element;

[0105] Fig. 6 is a schematic perspective view of another embodiment of a transmission line structure according to the invention; Figs. 7a, 7b are a schematic side view (Fig. 7a) and a schematic representation of a circuit diagram (Fig. 7b) of another exemplary series capacitive element;

[0106] Fig. 7c is a schematic side view of another exemplary series capacitive element;

[0107] Fig. 8a-8c are schematic perspective views of exemplary parallel inductive elements;

[0108] Fig. 9 is a schematic perspective view of an exemplary virtual mass element;

[0109] Fig. 10 is a schematic perspective view of exemplary symmetrically arranged parallel inductive elements;

[0110] Fig. 11a, 11b a respective schematic perspective view of two further embodiments of a transmission line structure according to the invention;

[0111] Fig. 12 is another schematic representation of a dispersion relation of an exemplary CRLH transmission line;

[0112] Fig. 13 is a schematic diagram of an exemplary CRLH transmission line;

[0113] Fig. 14 is a schematic perspective view of an embodiment of an antenna device according to the invention; Fig. 15 is a schematic representation of a relative signal strength of the reflection (S11 parameter) as a function of a frequency for the embodiment according to Fig. 14;

[0114] Fig. 16 is a schematic representation of a dispersion relation of the embodiment according to Fig. 14;

[0115] Fig. 17a-17e are respective schematic perspective views of further embodiments of an antenna device according to the invention;

[0116] Fig. 18a-18c show respective schematic perspective views of further embodiments of an antenna device according to the invention.

[0117] Detailed description of some preferred embodiments

[0118] Fig. 1a, 1b and 1c show schematic perspective views (Fig. 1a, 1b) and a schematic side view (Fig. 1c) of an exemplary PIF antenna (P1FA) 1.

[0119] PIF antennas describe a common antenna type with a relatively flat, compact design, which is used particularly for mobile radio frequencies, e.g., in smartphones, for indoor antennas for radio coverage in buildings, e.g., using so-called distributed antenna systems (DAS), and for antennas on cars, e.g., between the interior rearview mirror and the windshield or as a so-called shark fin antenna.

[0120] P1FA 1 comprises a flat metal strip 12 (an example of a flat conductor section) which is connected by means of a narrow flat metal section 20 (an example of a short-circuit connection element) at an edge of a short section of the metal strip 12 (an example of an end section of a conductor structure) to an electrically conductive ground plane 11 running parallel to the metal strip 12. A λ / 4 resonance (with wavelength λ) can form between the short-circuit connection formed by the metal section 20 and the open edge of the metal strip 12 shown on the right in Figs. 1a and 1b (an example of an open end or an open edge of a conductor structure), so that the P1FA 1 can emit and / or receive electromagnetic radiation at the open edge of the metal strip 12 (an example of a section for receiving and / or emitting electromagnetic radiation).

[0121] The wavelength X for an X / 4 or monopole resonance in a P1FA based on a microstrip line is approximately determined by the following equation: SMSL + w r + h = X / 4, with the length SMSL of the metal strip 12, the width w of the metal strip 12 and the width w s of the metal section 20 (with w r = w - w s ) and the height h of the metal strip 12 above the ground plane 11 (corresponding to the height of the P1FA 1). The length, in particular the total length, of the P1FA 1 in the case of resonance thus corresponds to a quarter of the free-space wavelength X. Rearranged for the length SMSL of the metal strip 12 and with X = c / f, the formation of an X / 4 resonance results in: SMSL = c / (4-f) - h - w r The height h can, for example, be between 0.5 and 50 mm. The width w of the metal strip 12 can, for example, be between 1 and 100 mm.

[0122] As shown in Figs. 1b and 1c, the P1FA 1 can further be fed in a suitable region between the metal strip 12 and the ground plane 11 by means of a coaxial line 30 (an example of a feed line), wherein an outer conductor of the coaxial line 30 is electrically connected to the ground plane 11 and an inner conductor of the coaxial line 30 is electrically connected to the metal strip 12 (the feed line is not shown in Fig. 1 for reasons of clarity). Between the metal strip 12 and the ground plane 11, there is air (an example of a dielectric interlayer) in the P1FA 1.

[0123] As can be seen in Figs. 1a to 1c, a P1FA has a comparatively flat, compact design and, in particular, a comparatively low overall height h. However, particularly in automotive applications, comparatively low (e.g., mobile radio) frequencies between 600 MHz and 1 GHz result in undesirably large sizes for corresponding PIFAs. In particular, the overall height and length of a PIFA should (also) be as small as possible without accepting significant performance losses. For example, for a PIFA with a height h = 5 mm and a frequency of 600 MHz (corresponding to a vacuum wavelength of 50 cm), the overall length SMSL is approximately 12 cm (according to the above equation).

[0124] Figs. 2a and 2b show schematic representations of respective circuit diagrams of an exemplary exclusively right-handed transmission line (Fig. 2a) and an exemplary CRLH transmission line (Fig. 2b). A circuit diagram can be understood in particular as an equivalent circuit diagram.

[0125] As shown in Fig. 2a, the right-handed transmission line includes an inductive element having an inductance LR in series with the transmission line and a capacitive element having a capacitance CR in parallel with the transmission line. As shown in Fig. 2b, in addition to the elements of the right-handed transmission line of Fig. 2a, the CRLH transmission line further includes a capacitive element having a capacitance CL in series with the transmission line and an inductive element having an inductance LL in parallel with the transmission line. Together, the inductive and capacitive elements in Fig. 2b form at least part of an exemplary CRLH transmission line.

[0126] Fig. 3 shows a schematic representation of a dispersion relation of an exemplary CRLH transmission line. The y-axis shows the frequency f as a function of the phase constant β, which is calculated as the quotient of 2θ and the electromagnetic wavelength X, i.e., according to β=2θr / λ. The two straight lines 51, 53 show the dispersion relation according to the equation f = ±βc / (2θr) with the speed of light c. The dispersion relation of the CRLH transmission line comprises a right-handed branch 52 (β > 0) and a left-handed branch 54 (β < 0). While the right-handed branch 52 approaches the straight line 51 at higher frequencies, the left-handed branch 54 deviates significantly from the straight line 53. Thus, for a given operating frequency fop (English: operating frequency), a left-handed wavelength ÄLH 56 results, which is significantly shorter than a corresponding free-space wavelength ATEM 55 of a transverse electromagnetic wave (English:: Transverse Electromagnetic Mode, TEM) (a larger value of the phase constant ß leads to a lower value for X).

[0127] Fig. 3 thus illustrates how an exemplary CRLH transmission line enables a reduction in an electromagnetic wavelength or, conversely, a reduction in the required size of a transmission line structure at a given operating frequency. In other words, Fig. 3 shows that a CRLH transmission line or a CRLH transmission line structure exhibits electromagnetic wave propagation characteristics that advantageously differ from the propagation characteristics of electromagnetic waves in naturally occurring materials or on conventional waveguides (represented by straight line 51, whose reflection 53 is shown for illustrative purposes only).

[0128] Fig. 4a shows a schematic perspective view of an embodiment of a transmission line structure according to the invention. The transmission line structure 100 comprises a ground plane 110 and a conductor structure 120 arranged above the ground plane. Ground plane 110 and conductor structure 120 together form at least part of a transmission line.

[0129] The conductor structure 120 comprises four equally sized metal strips 130, 132, 134, 136 (an example of the at least one inductive element arranged in series with respect to the transmission line), which, together with the ground plane 110, form a plurality of capacitive elements arranged in parallel with respect to the transmission line. A width of the conductor structure 120 can be, for example, between 1 and 100 mm, preferably between 2 and 50 mm. A height of the conductor structure 120 above the ground plane 110 can be, for example, between 0.5 and 50 mm, preferably between 1 and 20 mm. A respective distance between the metal strips 130, 132, 134, 136 can be, for example, between 0.1 and 5 mm, preferably between 0.2 and 2 mm.

[0130] The conductor structure 120 further comprises five, in particular double, capacitors (an example of the at least one capacitive element serially connected to the transmission line), of which only the capacitor 140 is provided with reference numerals for reasons of clarity. The capacitor 140 comprises two base layers formed by respective sections of the metal strips 130, 132, a cover layer 144, and a dielectric layer 142 between the base layers and the cover layer 144, which, for example, has a material-dependent permittivity e r The material-dependent permittivity e r can be, for example, between 1 and 10, preferably between 2 and 4, and can also be variable and / or, in particular electronically, controllable.

[0131] The other capacitors are constructed essentially analogously to capacitor 140, wherein in the two outer capacitors, a base layer is formed by respective sections of the outer metal strips 170, 172. A respective width b of the three inner capacitors (shown in Fig. 5a) can be, for example, between 0.05 and 30 mm, preferably between 0.2 and 10 mm. For the two outer capacitors, a respective width b c for example between 0.1 and 60 mm, preferably between 0.4 and 20 mm, the width b c in preferred embodiments is (approximately) twice the width b (ie b c = 2b).

[0132] As shown in Fig. 4a, the respective length of the capacitors can correspond to the width of the conductor structure 120. However, it is understood that the respective length of the capacitors can also be shorter than the width of the conductor structure, for example. The respective length of the capacitors can be, for example, between 1 and 100 mm, preferably between 2 and 50 mm.

[0133] The conductor structure 120 further comprises four identically designed wire elements (an example of the at least one inductive element parallel with respect to the transmission line) which electrically connect the conductor structure 120 and the ground plane 110 to one another and of which, for reasons of clarity, only the wire element 150 is provided with a reference numeral. The wire element 150 is arranged on an edge 131 of the metal strip 130. A respective width of a cross-section of the wire element 150 and of the further wire elements shown in Fig. 4a can be, for example, between 0.1 and 5 mm, preferably between 1 and 3 mm. A respective length of the wire element 150 and of the further wire elements shown in Fig. 4a can be, for example, between 1 and 300 mm, preferably between 3 and 50 mm.

[0134] Finally, there is a gap 160 between the conductor structure 120 and the ground plane 110, in which there is, in particular predominantly, air (an example of a dielectric interlayer).

[0135] Although the inductive elements parallel with respect to the transmission line are illustrated in Fig. 4a and in some other figures as wire elements with a substantially square cross-section, in preferred embodiments the inductive elements parallel with respect to the transmission line correspond to flat metal elements (e.g., metal strips) with a substantially rectangular cross-section, as illustrated, for example, in Figs. 11a, 11b. A respective thickness of these metal elements can, for example, correspond to a thickness of a respective sheet from which the conductor structure 120 was manufactured (e.g., by means of a stamping and / or bending process).

[0136] The ground plane 110, the metal strips 130, 132, 134, 136, the outer metal strips 170, 172, the cover layer 144 of the capacitor 140 and the cover layers of the further capacitors can in particular be designed as approximately ideal electrical conductors.

[0137] Because the transmission line structure 100 comprises at least one series inductive element (metal strips 130, 132, 134, 136), at least one parallel capacitive element (formed from metal strips 130, 132, 134, 136 and ground plane 110), at least one series capacitive element (e.g. (double) capacitor 140) and at least one parallel inductive element (e.g. wire element 150), the transmission line structure 100 forms at least part of a CRLH transmission line, whereby the wavelength of an electromagnetic wave forming on the transmission line structure 100 at a given operating frequency can be significantly reduced compared to the wavelength of an electromagnetic wave forming on transmission line structures without CRLH elements and thus a desired phase shift (e.g. by 90°) can be achieved (as explained above).

[0138] Fig. 4b shows a schematic representation of a circuit diagram of the embodiment according to Fig. 4a. In particular, Fig. 4b shows a circuit diagram of two CRLH unit cells with length p, as well as a circuit diagram of a section of an (exclusively right-handed) microstrip line (MSL) with length SMSL. The section of the microstrip line with length SMSL can be formed, for example, by a corresponding section of the metal strip 170 shown in Fig. 4a (an example of an exclusively right-handed conductor section) together with the ground plane 110.

[0139] The inductance Lk can be, for example, between 0.1 and 100 nH, preferably between 0.5 and 20 nH. The capacitance CR can be, for example, between 0.05 and 10 pF, preferably between 0.1 and 5 pF. The capacitance CL can be, for example, between 0.01 and 100 pF, preferably between 0.5 and 20 pF. The inductance LL can be, for example, between 0.05 and 200 nH, preferably between 1 and 50 nH. The length p of a CRLH unit cell can be, for example, between 1 and 100 mm, preferably between 2 and 20 mm. In preferred embodiments, the length p is less than a quarter of a free-space wavelength corresponding to a predetermined operating frequency.

[0140] Fig. 5a shows a schematic side view of an exemplary series capacitive element in the form of a (double) capacitor 140 (twin-C capacitor). As already explained in connection with Fig. 4a, the capacitor 140 comprises two base layers, which are formed by respective sections of the metal strips 130, 132, a cover layer 144 and a dielectric layer 142 between the base layers and the cover layer 144. The metal strips 130, 132 and the cover layer 144 can in particular be designed as approximately ideal electrical conductors. Electric fields 146 can form between the cover layer 144 and the base layers. A respective individual capacitor of the (double) capacitor 140 has a width b. A distance d is between the base layers and the cover layer 144. The width b can be, for example, between 0.05 and 30 mm, preferably between 0.2 and 10 mm.The distance d can be, for example, between 0.005 and 3 mm, preferably between 0.025 and 0.25 mm.

[0141] Fig. 5b shows a schematic representation of a circuit diagram of the (double) capacitor 140 with the total capacitance CL, which can be, for example, between 0.01 and 100 pF, preferably between 0.5 and 20 pF. In preferred embodiments, each of the at least one capacitive element serial with respect to the transmission line comprises exactly two capacitive sub-elements serial with respect to the transmission line, wherein preferably a total capacitance CL of each of the at least one capacitive element serial with respect to the transmission line corresponds exactly to the reciprocal of the sum of two reciprocal double capacitances, wherein each serial capacitive sub-element provides a double capacitance (CL = ((2CL) -1 + (2CL) -1 )' 1). Fig. 5c shows a schematic side view of another exemplary series capacitive element in the form of another (double) capacitor 140a with two base layers formed by respective sections of the metal strips 130a, 132a, a cover layer 144a, and a dielectric layer 142a between the base layers and the cover layer 144a. In contrast to the dielectric layer 142 in capacitor 140, the dielectric layer 142a extends beyond an extent of the cover layer 144a, thereby achieving particularly economical manufacturability of the series capacitive element, since, for example, a polyimide film or a dielectric substrate provided with the cover layer 144a can be applied with less effort in this case. A respective distance between the metal strips 130a, 132a and the cover layer 144a can be, for example, between 0.005 and 3 mm, preferably between 0.025 and 0.25 mm.

[0142] Fig. 6 shows a schematic perspective view of another embodiment of a transmission line structure according to the invention. The transmission line structure 100' comprises a ground plane 110' and a conductor structure 120' arranged above the ground plane. The ground plane 110' and the conductor structure 120' together form at least part of a transmission line.

[0143] The conductor structure 120' comprises four similarly sized metal strips 130', 132', 134', 136' (an example of the at least one inductive element arranged in series with respect to the transmission line), which, together with the ground plane 110, form a plurality of capacitive elements arranged in parallel with respect to the transmission line. A width of the conductor structure 120' can be, for example, between 1 and 100 mm, preferably between 2 and 50 mm. A height of the conductor structure 120' above the ground plane 110' can be, for example, between 0.5 and 50 mm, preferably between 1 and 20 mm.

[0144] The conductor structure 120' further comprises five capacitors (an example of the at least one capacitive element serially connected to the transmission line), of which only the capacitor 140' is provided with reference numerals for reasons of clarity. The capacitor 140' comprises two base layers formed by respective portions of the metal strips 130', 132' and which at least partially overlap, as well as a dielectric layer 142' between the overlapping base layers. The dielectric layer 142' can, for example, have a material-dependent permittivity e r The material-dependent permittivity e rcan be, for example, between 1 and 10, preferably between 2 and 4, and can be variable and / or, in particular electronically, controllable. The other capacitors shown in Fig. 6 are constructed essentially analogously to capacitor 140', wherein in the two outer capacitors, a base layer is formed by respective sections of the outer metal strips 170', 172'. In the two outer capacitors, a respective width b c for example between 0.1 and 60 mm, preferably between 0.4 and 20 mm, the width b c in preferred embodiments is (approximately) twice the width b (ie b c = 2b).

[0145] The conductor structure 120' further comprises four wire elements (an example of the at least one inductive element parallel with respect to the transmission line) which electrically connect the conductor structure 120' and the ground plane 110' to one another and of which two are each identical to one another. For reasons of clarity, only the two differently designed, adjacent wire elements 150' and 151' are provided with a reference numeral. A respective width of a cross-section of the wire elements 150', 151' and the further wire elements shown in Fig. 6 can be, for example, between 0.1 and 5 mm, preferably between 1 and 3 mm. A respective length of the wire elements 150', 151' and the further wire elements shown in Fig. 6 can be, for example, between 1 and 300 mm, preferably between 3 and 50 mm.

[0146] The ground plane 110', the metal strips 130', 132', 134', 136' and the outer metal strips 170', 172' can be designed, for example, as approximately ideal electrical conductors. Because the transmission line structure 100' each has at least one series inductive element (metal strips 130', 132', 134', 136'), at least one parallel capacitive element (formed from metal strips 130', 132', 134', 136' and ground plane 110'), at least one series capacitive element (e.g., capacitor 140') and at least one parallel inductive element (e.g.,Wire element 150'), the transmission line structure 100' forms at least part of a CRLH transmission line, whereby - just as in the case of the transmission line structure 100 - the wavelength of an electromagnetic wave forming on the transmission line structure 100' at a given operating frequency can be significantly reduced compared to the wavelength of an electromagnetic wave forming on transmission line structures without CRLH elements and thus a desired phase shift (e.g. by 90°) can be achieved on a significantly shorter section of the transmission line structure (as explained above).

[0147] The circuit diagram of the exemplary embodiment according to Fig. 4a, shown schematically in Fig. 4b, applies accordingly to the exemplary embodiment according to Fig. 6. The section of the microstrip line with the length SMSL shown in Fig. 4b can be formed, for example, by a corresponding section of the metal strip 170' shown in Fig. 6 (an example of an exclusively right-handed conductor section) together with the ground plane 110'. The exemplary value ranges for the inductance LR, the capacitance CR, the capacitance CL, the inductance LL and the length p of a CRLH unit cell mentioned above in connection with Fig. 4b also apply accordingly to the exemplary embodiment according to Fig. 6.

[0148] Fig. 7a shows a schematic side view of another exemplary series capacitive element in the form of a capacitor 140'. As already explained in connection with Fig. 6, the capacitor 140' comprises two base layers, which are formed by respective sections of the metal strips 130', 132' and which at least partially overlap, as well as a dielectric layer 142' between the overlapping base layers. An electric field 146' can form between the base layers. Capacitor 140' has a width b. There is a distance d between the base layers. The width b can be, for example, between 0.05 and 30 mm, preferably between 0.2 and 10 mm. The distance d can be, for example, between 0.005 and 3 mm, preferably between 0.025 and 0.25 mm.

[0149] Fig. 7b shows a schematic representation of a circuit diagram of the capacitor 140' with the capacitance CL, which can be, for example, between 0.01 and 100 pF, preferably between 0.5 and 20 pF.

[0150] Fig. 7c shows a schematic side view of another exemplary series capacitive element in the form of another capacitor 140a' with two base layers formed by respective sections of the metal strips 130a', 132a', which at least partially overlap, and with a dielectric layer 142a' between the overlapping base layers. Unlike the dielectric layer 142' in capacitor 140', the dielectric layer 142a' extends beyond the area where the base layers overlap, thereby achieving particularly economical manufacturability of the series capacitive element, since, for example, a polyimide film or a dielectric substrate provided with the metal strip 132a' can be applied with less effort in this case. The distance between the metal strips 130a', 132a' can be, for example, between 0.005 and 3 mm, preferably between 0.025 and 0.25 mm.

[0151] Fig. 8a-8c show schematic perspective views of exemplary parallel inductive elements in the form of wire elements 150a, 150b, 150c. For reasons of clarity, only one exemplary metal strip 130 of a corresponding conductor structure 120 (not shown in Fig. 8a-8c) is shown in each case. In an embodiment advantageous for the inductive effect, the wire element has a small width, i.e. a width that is preferably less than half the length (i.e. the extension in the propagation direction of the electromagnetic wave) of the metal strip 130 (limited downwards by a required mechanical stability) and the greatest possible length.

[0152] The wire elements 150a, 150b, 150c are each arranged at an edge of the metal strip 130. The wire element 150a has a kink (an example of a kinked section), so that the wire element 150a has an overall L-shaped section. The wire element 150b has no bent, curved, and / or kinked sections, so that the wire element 150b has only straight sections. The wire element 150c has a plurality (eight in total) of kink (an example of a plurality of kinked sections), so that the wire element 150c has a plurality of meandering sections.

[0153] In particular, wire elements 150a and 150c enable a further reduction of the overall size, in particular the overall height, of a transmission line structure, since by providing one or more bends, an overall length required for a respective electromagnetic wavelength can be provided in a spatially advantageous manner, namely with a comparatively low overall height.

[0154] In general, this design of the wire elements makes it possible to realize the parallel inductance required for shortening the wavelength independently of the geometric parameters that are decisive for the optimal design of the antenna or the transmission line.

[0155] Wire element 150b has the lowest complexity and can therefore be manufactured particularly economically.

[0156] Fig. 9 shows a schematic perspective view of an exemplary virtual ground element 180, via which a wire element 150 electrically connects a metal strip 130 (which may, for example, be encompassed by a conductor structure) and a ground plane 110. The virtual ground element 180 comprises a dielectric layer 183 and an electrically conductive cover layer 182, on which a galvanic contact 181 is provided. A galvanic contact can be understood, for example, as a contact that establishes a direct electrical connection. A direct electrical connection can be understood, for example, as a continuous, in particular material, electrical connection using a material with high electrical conductivity (e.g., copper).In preferred embodiments, the virtual ground element 180 is configured to maintain a constant potential despite flowing electrical currents and thus to “virtually” electrically connect the metal strip 130 to the ground surface 110.

[0157] Fig. 10 shows a schematic perspective view of exemplary symmetrically arranged parallel inductive elements in the form of wire elements 150d, which electrically connect a metal strip 130 (which may, for example, be encompassed by a conductor structure) and a ground plane 110. The two wire elements 150d are arranged symmetrically, in particular with respect to the metal strip 130 and / or a conductor structure encompassing the metal strip. A transmission line structure with such symmetrically arranged inductive elements 150d has (even) further improved structural stability. Furthermore, transmission line structures with such symmetrically arranged inductive elements 150d, in particular, have an advantageous, particularly symmetrical distribution of the electromagnetic fields.

[0158] It is understood that the geometric dimensions of the elements and structures illustrated in Figs. 8a-8c, 9, and 10 can, in particular, correspond to the exemplary geometric dimensions of corresponding elements and structures specified above. Figs. 11a and 11b show a respective schematic perspective view of two further embodiments of a transmission line structure according to the invention.

[0159] While in the transmission line structure in Fig. 11a all parallel inductive elements are formed on the same side of a conductor structure of the transmission line structure, in the transmission line structure in Fig. 11b the parallel inductive elements are formed alternately on opposite sides of a conductor structure of the transmission line structure.

[0160] While the equilateral arrangement (Fig. 11a) results in stronger magnetic coupling between the inductive elements, the alternating arrangement (Fig. 11b) reduces the effect of magnetic coupling between the parallel inductive elements (this can, for example, simplify the design of the geometry of the wire elements used). Furthermore, it has been shown that the base layers forming the series inductive elements can be selected (even) shorter with an alternating arrangement of the parallel inductive elements (as exemplified in Fig. 11b), which advantageously allows the overall length to be reduced (even) further.

[0161] In preferred embodiments, the at least one inductive element parallel with respect to the transmission line is therefore formed either exclusively on a single longitudinal side of the conductor structure or alternately on opposite longitudinal sides of the conductor structure.

[0162] It is understood that the geometric dimensions, the inductances and / or the capacitances of the (elements of) the transmission line structures 100" shown in Figs. 11a and 11b can correspond in particular to the above-specified exemplary geometric dimensions, inductances and capacitances of corresponding elements and transmission line structures. Fig. 12 shows a further schematic representation of a dispersion relation of an exemplary CRLH transmission line. The y-axis shows the phase constant ß as a function of the frequency f. The straight line 62 shows the dispersion relation according to the equation ß=2irf / c with the speed of light c. Curve 61 shows the dispersion relation -ß(CRLH) of a balanced CRLH transmission line as a function of the frequency f. A passband of the CRLH transmission line lies between approximately 0.8 GHz and 4.8 GHz (reference symbol 63, 64).

[0163] As can be seen in Fig. 12, the phase constant -ß(CRLH) according to the dispersion relation 61 at a frequency of 1 GHz is approximately a factor of 3 larger than the phase constant ß=2irf / c according to the dispersion relation 62 (about 60 m _1 / 20 no 1). As a result, the wavelength X corresponding to the phase constant -ß(CRLH) is approximately a factor of 3 smaller according to dispersion relation 61 than in the case of dispersion relation 62. This advantageously enables a reduction of the overall length of the CRLH transmission line required for a desired phase shift by approximately this factor. In other words, Fig. 12 shows that a CRLH transmission line or CRLH transmission line structure has propagation properties for electromagnetic waves that advantageously differ from the propagation properties of electromagnetic waves in naturally occurring materials or on conventional transmission line structures (represented by straight line 62).

[0164] Fig. 13 shows a schematic representation of a circuit diagram of an exemplary CRLH transmission line. The CRLH transmission line shown comprises (at least) two CRLH (unit) cells, each with a length p, which can be, for example, between 1 and 100 mm, preferably between 2 and 20 mm. It is further understood that the inductances LR, L and capacitances CR, CL shown in Fig. 13 can correspond in particular to the exemplary inductances and capacitances specified with reference to Fig. 4b. Fig. 14 shows a schematic perspective view of an embodiment of an antenna device according to the invention.The antenna device 1000 comprises a transmission line structure 100 (an example of a transmission line structure according to the first aspect) with a conductor structure 120 and a ground plane 110, as well as a short-circuit connection element 200 for establishing a short-circuit connection between an end portion of the conductor structure 120 and the ground plane 110. A metal strip 134 encompassed by the conductor structure 120 has, on its side shown on the right in Fig. 14, an open edge (an example of an open end or an open edge of a conductor structure), at which the antenna device 1000 can emit and / or receive electromagnetic radiation (an example of a portion for receiving and / or emitting electromagnetic radiation).The short-circuit connection element 200 between the conductor structure 120 and the ground plane 110 enables the formation of a resonance, in particular a λ / 4 resonance, between the short-circuit connection element 200 and the open end or edge of the metal strip 134.

[0165] It is understood that the geometric dimensions, the inductances and / or the capacitances of the (elements of the) antenna device 1000 or the transmission line structure 100 may in particular correspond to the above-specified exemplary geometric dimensions, inductances and capacitances of corresponding elements, antenna devices and transmission line structures.

[0166] Because the antenna device 1000 comprises the transmission line structure 100 (as an example of a transmission line structure according to the first aspect), which can have a significantly reduced size due to its special electromagnetic properties (as explained above), the antenna device 1000 has a significantly reduced size compared to antennas, in particular PIFAs, without a CRLH structure, which is particularly advantageous in the automotive and / or mobile communications sectors.

[0167] Thus, the quantity s shown in Fig. 14 ra length of a, in particular exclusively, right-handed section, which at operating frequencies of 0.915 GHz or 0.5 GHz can be, for example, 10 mm. Furthermore, the length SCRLH denotes a total length of the three CRLH cells of the conductor structure 120. SCRLH corresponds to the product of the number N of CRLH cells and the length p of each individual CRLH cell, i.e. SCRLH = Np. At the stated operating frequencies, the number N can be, for example, 3 and the length p, for example, 10 mm. The length, in particular the total length, of the conductor structure 120 or the transmission line structure 100 and thus of the antenna device 1000 can therefore advantageously be, for example, (only) 40 mm at the stated operating frequencies.

[0168] In contrast, the length SMSL of a P1FA with a microstrip line without CRLH structure (for example, the P1FA 1 shown in Fig. 1a) is calculated according to SMSL = c / (4-f)-h for the mentioned operating frequencies and with h = 5 mm to be 76.91 mm (at 0.915 GHz) or 144.9 mm (at 0.5 GHz).

[0169] Consequently, the conductor structure 120 and thus the transmission line structure 100 or the antenna device 1000 can, purely by way of example, have a length, in particular a total length, of (only) 40 mm in order to be able to operate at the operating frequencies of 0.5 GHz and 0.915 GHz, whereas a P1FA with a microstrip line without a CRLH structure must have a length of approximately 77 mm (at 0.915 GHz) or approximately 145 mm (at 0.5 GHz) at these operating frequencies in order to be able to operate resonantly. Thus, the transmission line structure 100 or the antenna device 1000 advantageously enable a reduction in size, in particular in length, by a factor of approximately 1.925 or 3.625, respectively. In preferred embodiments, the antenna device 1000 further comprises a feed line (not shown in Fig. 14) to which the conductor structure 120 and / or the ground plane 110 can be connected and / or are connected.In preferred embodiments, the antenna device 1000 is a PIF antenna device (PIFA). Since the transmission line structure 100 may be referred to as a CRLH transmission line structure (see above), the antenna device 1000 may therefore be referred to, for example, as a CRLH PIFA.

[0170] Fig. 15 shows a schematic representation of a relative signal strength of the reflection (S11 parameter) as a function of a frequency for the exemplary embodiment according to Fig. 14. As can be seen in Fig. 15, the relative signal strength is maximum at the two operating frequencies 71, 72 of the antenna device 1000. A phase shift of -90° occurs at the operating frequency 71, and a phase shift of -270° occurs at the operating frequency 72. The first operating frequency 71 is 0.915 GHz, and the second operating frequency 72 is 0.5 GHz.

[0171] Fig. 16 shows a schematic representation of a dispersion relation of the exemplary embodiment according to Fig. 14. The y-axis shows the phase constant β as a function of the frequency f. The straight line 81 shows the dispersion relation according to the equation β = 2ir-f / c with the speed of light c. The curve 82 shows the dispersion relation of an exemplary CRLH-PIFA. As can be seen in Fig. 16, the phase constant -β(CRLH) according to the dispersion relation 82 is considerably greater at the two operating frequencies 83, 84 than the phase constant β = 2irf / c according to the dispersion relation 81, so that the wavelength X corresponding to the phase constant -β(CRLH) for a CRLH-PIFA is considerably smaller than in the case of the dispersion relation 81, which advantageously enables a reduction in the size of the exemplary CRLH-PIFA, particularly at a given frequency. In other words, Fig. 16 shows that the embodiment of a CRLH-PIFA according to Fig.14 has propagation properties for electromagnetic waves which differ advantageously from the propagation properties of electromagnetic waves in naturally occurring materials or on ordinary waveguides or on ordinary transmission line structures (represented by the straight line 81).

[0172] Figs. 17a-17e show respective schematic perspective views of further embodiments of an antenna device according to the invention. The antenna devices 1000a-1000e each comprise a transmission line structure 100a-100e with a respective conductor structure 120a-120e and a respective ground plane 110a-110e.

[0173] The size s rdenotes a respective length of a, in particular exclusively, right-handed section of the conductor structures. Furthermore, the length SCRLH denotes a total length of the respective CRLH cells of the conductor structures, and the length p denotes a length of a respective CRLH (unit) cell.

[0174] The antenna devices 1000a-1000e further comprise a respective short-circuit connection element 200a-200e for establishing a short-circuit connection between the conductor structures 120a-120e and the ground planes 110a-110e.

[0175] In preferred embodiments, the antenna devices 1000a-1000e further comprise a feed line (not shown in Figs. 17a-17e) to which the conductor structures 120a-120e and / or the ground planes 110a-110e are electrically connectable and / or connected. In preferred embodiments, the antenna devices 1000a-1000e are PIF antenna devices (PIFAs).

[0176] Fig. 17a shows an antenna device 1000a with a transmission line structure 100a with (only) one double capacitor, (only) one wire element, and (only) one CRLH cell. The antenna device 1000a is particularly advantageous with regard to a desired reduction in size, in particular in length, since it comprises a particularly short implementation of a transmission line structure according to the invention or represents a particularly short implementation of an antenna device according to the invention.

[0177] In particular, the antenna device 1000a has a total length of less than 1.5 p (2 p / 2 + PT / 2, rnitp < p). In this context, the antenna device 1000a can be considered, for example, as an embodiment of a CRLH-P1FA based on one and a half (1.5) CRLH (unit) cells.

[0178] The antenna devices 1000b, 1000c, and 1000e shown in Figs. 17b, 17c, and 17e further comprise, in addition to the CRLH cells, exclusively right-handed conductor sections 170b, 170c, and 170e, which, together with the ground planes 110b, 110c, and 110e, form exclusively right-handed transmission lines, at least in sections. The CRLH cells each contribute a negative phase shift, while the exclusively right-handed conductor sections 170 each contribute a positive phase shift.

[0179] Fig. 17d shows a region 5 in which electromagnetic fringing fields make an effective contribution to a right-hand portion of the conductor structure 120d. By taking this effective contribution into account, the conductor structure 120d, in particular the section of the conductor structure 120d located to the right of the rightmost wire element, and thus the transmission line structure 100d and the antenna device 1000d, can advantageously be designed (even) shorter. In preferred embodiments, the conductor structure is therefore designed such that an effective contribution of electromagnetic fringing fields is taken into account.

[0180] It is understood that the geometric dimensions, the inductances and / or the capacitances of the (elements of the) antenna devices 1000a-1000e or the transmission line structures 100a-100e may in particular correspond to the above-specified exemplary geometric dimensions, inductances and capacitances of corresponding elements, antenna devices and transmission line structures.

[0181] Figs. 18a-18c show respective schematic perspective views of further embodiments of an antenna device according to the invention. In addition to the wire element forming the respective CRLH (unit) cell, the antenna devices 10001 (Fig. 18a) and 10001 (Fig. 18c) each comprise a further wire element. In the antenna device 10001, this additional wire element replaces the short-circuit connection element.

[0182] In the example of the antenna device 1000k (Fig. 18b), the width WSH of the short-circuit connection element corresponds approximately to half the width WMSL of the conductor structure, i.e., WSH = WMSL / 2. However, it is understood that the width WSH may, in particular, also be less than half the width WMSL and / or that the short-circuit connection element may be arranged at any position at the edge of the conductor structure (e.g., at the front (as shown in Fig. 18c), at the rear, or at a position in between).

[0183] It is understood that the geometric dimensions, the inductances and / or the capacitances of the (elements of the) antenna devices 10001, 1000k and 10001 or the corresponding transmission line structures may in particular correspond to the above-specified exemplary geometric dimensions, inductances and capacitances of corresponding elements, antenna devices and transmission line structures.

[0184] Furthermore, the above statements regarding the antenna devices 1000a-1000e shown in Figs. 17a-17e apply accordingly to the antenna devices 10001, 1000k, and 10001. In particular, the above statements regarding the antenna device 1000a shown in Fig. 17a also apply accordingly, since the antenna devices 10001, 1000k, and 10001 each also comprise (only) one CRLH (unit) cell, whereby the size of these antenna devices is advantageously particularly small. Against this background, the antenna devices 10001, 1000k, and 10001 can (also) be regarded, for example, as embodiments of a CRLH-P1FA based on one and a half (1.5) CRLH (unit) cells.

[0185] The invention is not limited to the embodiments or exemplary embodiments illustrated in the figures. The embodiments or exemplary embodiments of the present invention described in this specification and the optional features and properties cited in relation thereto are also to be understood as disclosed in all combinations with one another. In particular, the description of a feature encompassed by an embodiment or exemplary embodiment should not be understood in this case to imply that the feature is essential or essential for the function of the embodiment or exemplary embodiment, unless explicitly stated otherwise.

[0186] Furthermore, common measures for improving transmission properties of transmission line structures and (PlF) antenna devices - such as the insertion of slots and / or recesses in respective conductor structures or base layers and / or in respective ground planes (e.g. in order to increase a usable bandwidth) - in combination with the described transmission line structures or

[0187] Antenna devices are understood to be disclosed.

[0188] Terms used in the claims such as "comprise," "have," "include," "contain," and the like do not exclude further elements or steps. The phrase "at least partially" encompasses both "partially" and "completely." The phrase "and / or" is intended to indicate that both the alternative and the combination are disclosed, thus "A and / or B" means "(A) or (B) or (A and B)." The use of the indefinite article does not exclude a plurality. A single device can perform the functions of several units or devices mentioned in the claims. Reference symbols indicated in the claims are not to be construed as limitations on the means and steps employed.

[0189] List of reference symbols

[0190] I PIF antenna (P1FA)

[0191] 5 stray field area

[0192] II Ground plane

[0193] 12 metal strips

[0194] 20 metal sections

[0195] 30 coaxial cable

[0196] 51, 53 straights

[0197] 52 Right-handed branch

[0198] 54 Left-handed branch

[0199] 55 free space wavelength

[0200] 56 Left-handed wavelength

[0201] 61 Curve

[0202] 62 straight

[0203] 63, 64 Cutoff frequencies of the passband

[0204] 71.72 operating frequencies

[0205] 81 straight

[0206] 82 Curve

[0207] 83, 84 Operating frequencies

[0208] 100 transmission line structure

[0209] 110 Ground plane

[0210] 120 ladder structure

[0211] 130-136 metal strips

[0212] 131 Edge of the metal strip 130

[0213] 140 Capacitor

[0214] 142 Dielectric layer

[0215] 144 Top layer 146 Electric fields

[0216] 150 wire element

[0217] 160 gap

[0218] 170, 172 Outer metal strips

[0219] 180 Virtual mass element

[0220] 181 Galvanic contact

[0221] 182 Top layer

[0222] 183 Dielectric layer

[0223] 200 short-circuit connection element

[0224] 1000 antenna device

Claims

P a t e n t a n s p r ü c h e 1.A transmission line structure comprising a ground plane and a conductor structure arranged above the ground plane, which conductor structure together with the ground plane forms at least part of a transmission line; wherein the conductor structure comprises at least one inductive element that is series with the transmission line and, together with the ground plane, forms at least one capacitive element that is parallel with the transmission line; wherein the conductor structure further comprises at least one capacitive element that is series with the transmission line and at least one inductive element that is parallel with the transmission line; wherein the at least one inductive element that is parallel with the transmission line electrically connects the conductor structure and the ground plane; and wherein the at least one capacitive element that is series with the transmission line comprises two electrically conductive base layers and a dielectric layer, wherein either. • the base layers at least partially overlap and the dielectric layer is provided between the base layers, or • the at least one capacitive element serial with respect to the transmission line further comprises an electrically conductive cover layer arranged over the base layers and the dielectric layer is provided between the base layers and the cover layer.

2. Transmission line structure according to claim 1, further comprising a dielectric layer arranged between the ground plane and the conductor structure Intermediate layer, which preferably consists at least partly of air and / or only partly of a solid.

3. Transmission line structure according to one of the preceding claims, wherein the at least one inductive element which is serial with respect to the transmission line is formed at least in sections as a planar conductor section and / or wherein the conductor structure comprises at least one planar conductor section which, together with the ground surface, forms the at least one capacitive element which is parallel with respect to the transmission line.

4. Transmission line structure according to claim 3, wherein the at least one inductive element parallel with respect to the transmission line is arranged at a respective edge of the at least one planar conductor section.

5. A transmission line structure according to any one of the preceding claims, wherein the at least one inductive element parallel with respect to the transmission line has one or more bent, curved and / or kinked sections.

6. Transmission line structure according to one of the preceding claims, wherein the at least one inductive element parallel with respect to the transmission line has one or more straight, L-shaped and / or meandering sections.

7. Transmission line structure according to one of the preceding claims, wherein the at least one inductive element which is serial with respect to the transmission line, the at least one inductive element which is parallel with respect to the transmission line and / or the ground plane are formed in one piece.

8. Transmission line structure according to one of the preceding claims, wherein the at least one parallel with respect to the transmission line inductive element comprises at least two inductive elements arranged symmetrically with respect to the conductor structure.

9. Transmission line structure according to one of the preceding claims, wherein the at least one inductive element which is in series with respect to the transmission line, the at least one capacitive element which is in parallel with respect to the transmission line, the at least one capacitive element which is in series with respect to the transmission line and the at least one inductive element which is in parallel with respect to the transmission line together form at least one CRLH cell which, together with the ground plane, forms at least in sections a CRLH transmission line.

10. Transmission line structure according to one of the preceding claims, wherein the conductor structure further comprises at least one exclusively right-handed conductor section which, together with the ground plane, forms at least in sections an exclusively right-handed transmission line.

11. Transmission line structure according to one of the preceding claims, wherein at least one virtual ground element is provided on the ground plane, via which the at least one inductive element parallel with respect to the transmission line electrically connects the conductor structure and the ground plane.

12. Transmission line structure according to one of the preceding claims, further comprising at least one further conductor structure arranged above the ground plane, which together with the ground plane forms at least a part of at least one further transmission line, wherein the at least one further conductor structure is arranged substantially perpendicular and / or substantially parallel to the conductor structure, wherein preferably a part of the conductor structure simultaneously forms a part of the at least one further conductor structure.

13. Transmission line structure according to one of the preceding claims, further comprising at least one short-circuit connection element for establishing a short-circuit connection between the conductor structure and the ground plane.

14. The transmission line structure according to claim 13, wherein the short-circuit connection element is arranged at an end portion of the conductor structure with respect to a longitudinal axis of the conductor structure, and wherein the short-circuit connection element establishes the short-circuit connection between the end portion of the conductor structure and the ground plane.

15. Transmission line structure according to one of the preceding claims, wherein the conductor structure has at least one section for receiving and / or emitting electromagnetic radiation.

16. Antenna device, in particular PIF antenna device, comprising a transmission line structure according to one of the preceding claims.

17. Antenna device according to claim 16, further comprising a feed line to which the conductor structure and / or the ground plane are connectable and / or connected.

18. A method for producing a transmission line structure, in particular a transmission line structure according to one of claims 1 to 15, the method comprising: Providing a ground plane; and providing a conductor structure arranged above the ground plane, which together with the ground plane forms at least part of a transmission line; wherein the conductor structure comprises at least one inductive element serial with respect to the transmission line, at least one capacitive element serial with respect to the transmission line, and at least one inductive element parallel with respect to the transmission line, and wherein the conductor structure together with the ground plane further forms at least one capacitive element parallel with respect to the transmission line; wherein the at least one inductive element parallel with respect to the transmission line electrically connects the conductor structure and the ground plane; and wherein the at least one capacitive element serial with respect to the transmission line comprises two electrically conductive base layers and a dielectric layer, wherein either • the base layers at least partially overlap and the dielectric layer is provided between the base layers, or • the at least one capacitive element serial with respect to the transmission line further comprises an electrically conductive cover layer arranged over the base layers and the dielectric layer is provided between the base layers and the cover layer.

19. Method according to claim 18, wherein the method, in particular the provision of the conductor structure, comprises one or more steps of a punching and / or bending process.

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