Multiband loop antenna for wi-fi 6e

Abstract

The invention relates to a multiband loop antenna (100) which comprises: a first, electrically conductive, L-shaped substructure (110) on a first layer (151) of a printed circuit board (150); and a second, electrically conductive, L-shaped substructure (120) on the first layer (151) of the printed circuit board (150), the first substructure (110) and the second substructure (120) being capacitively coupled to one another in a coupling region (108). The antenna (100) also comprises an electrically conductive first reference region (105), the first substructure (110) and the second substructure (120) being arranged on the first layer (151) of the printed circuit board (150) in such a way that they form a loop together with the first reference region (105). Furthermore, the antenna (100) comprises a feed line (115) which is electrically conductively coupled to the second substructure (120).

Description

[0001] Multi-band loop antenna for Wifi 6E

[0002] The invention relates to a multi-band loop antenna for transmitting or receiving radio signals, wherein the loop antenna is implemented on a circuit board.

[0003] An electronic device configured to communicate via a wireless communications network typically comprises at least one antenna for receiving and / or transmitting radio signals. The electronic device can be designed to receive and transmit radio signals over a plurality of different frequency bands, in particular over two different frequency bands or frequency ranges. For this purpose, the device can comprise a multi-band antenna, in particular a dual-band antenna. Exemplary dual-band antennas can be provided, for example, for the frequency bands 2.3 - 2.6 GHz and 4.7 - 7.0 GHz, i.e. for WLAN (Wireless Local Area Network) 6E. It may be necessary or desirable to efficiently expand the bandwidth of at least one of the frequency bands, for example, in order to also be able to receive and / or transmit WLAN frequencies at 6 to 7 GHz.

[0004] Antennas typically require a reference ground or reference plane to function. The size and shape of such a reference ground typically have a significant influence on the function and radiation characteristics of an antenna. An antenna is often intended to be used as a printed circuit board structure or as an attached metal structure (e.g., as a stamped and bent part) in printed circuit boards of different sizes. The different sized printed circuit boards represent differently pronounced reference grounds for an antenna. Furthermore, plastic in the vicinity of the antenna (e.g., due to a housing) can also influence the properties of an antenna. As a result, a new antenna tuning is typically required for each printed circuit board geometry and / or application. This type of antenna tuning can be achieved, for example, by changing the antenna structure.

[0005] This document addresses the technical problem of providing a (multi-band or dual-band) antenna with one or more extended frequency bands that can be efficiently integrated (in particular, without requiring dedicated antenna tuning) on ​​circuit boards of different sizes and / or in different environments. In other words, the goal is to provide a multi-band antenna with at least one extended frequency band that is insensitive to variations in the antenna's environment.

[0006] The problem is solved by the independent claim. Advantageous embodiments are described, among others, in the dependent claims.

[0007] According to one aspect, a multi-band loop antenna is described. The multi-band loop antenna described in this document can be efficiently implemented on differently dimensioned circuit boards and / or in different environments or applications (in particular in different devices). A circuit board typically comprises an electrically conductive first (outer) layer (e.g., a front layer) and an electrically conductive second (outer) layer (e.g., a bottom layer). The one or more layers can be electrically insulated from one another by one or more dielectric layers. The first and second layers can each contain an electrically conductive material, in particular copper. In particular, the first and second layers can each consist of an electrically conductive material, in particular copper.In this case, the electrically conductive material may have been removed from the respective layer at least in part, in particular in order to form a free space or a gap between an (electrically conductive) antenna structure (with a first and a second partial structure) and an (electrically conductive) reference region.

[0008] The multi-band loop antenna comprises a first, electrically conductive, L-shaped substructure on the first layer of the circuit board. The first substructure can have a first resonant frequency. In particular, the first substructure can form a first L-antenna for a first frequency range around the first resonant frequency. The first frequency range can cover 2.3–2.6 GHz. In particular, the first frequency range can be limited to the range 2.3–2.6 GHz.

[0009] Furthermore, the multi-band loop antenna comprises a second, electrically conductive, L-shaped substructure on the first layer of the circuit board. The second substructure can be configured for a second resonant frequency and thus for a second frequency range. The second substructure can form a second L-shaped antenna for the second frequency range around the second resonant frequency. The second frequency range can comprise 4.7–7.0 GHz. In particular, the second frequency range can be limited to the range 4.7–7.0 GHz.

[0010] The multi-band loop antenna has a feed line through which a transmitted RF (radio frequency) signal can be fed into the antenna and / or a received RF signal can be fed out of the antenna. The feed line is electrically conductively coupled to the second substructure, in particular to the first leg of the second substructure.

[0011] The multi-band loop antenna is thus fed via the second substructure for the second frequency range, so that the first substructure (for the first frequency range) is fed indirectly via the second substructure. This increases the quality of matching in the first frequency range.

[0012] The first substructure and the second substructure are preferably capacitively coupled to one another in a coupling region. The coupling region can be configured such that an RF signal with a frequency from the first frequency range is transmitted via the coupling region (e.g., from the feed line of the multi-band loop antenna (via the second substructure) to the first substructure or from the first substructure (via the second substructure) to the feed line).

[0013] The multi-band loop antenna further comprises an electrically conductive first reference region, which may, for example, be connected to a ground potential. The area of ​​the first reference region is typically significantly larger than the area of ​​the two substructures, in particular by a factor of 5 or more, or 10 or more.

[0014] The first substructure and the second substructure are preferably arranged on the first layer of the circuit board such that, together with the first reference area, they form a loop or frame. Thus, a loop antenna composed of multiple substructures, each for a different frequency range, can be provided. This makes it possible to provide a multi-band loop antenna that is insensitive to changes in the antenna's environment and can thus be flexibly integrated into different devices.

[0015] The first substructure can be electrically conductively connected to the first reference region and can in particular be designed as a parasitic element of the multi-band loop antenna.

[0016] The first partial structure can have a first leg and a second leg, which together form the L-shape. The first leg can be shorter than the second leg. The first leg of the first partial structure can extend, in particular perpendicularly, along a longitudinal axis (or along a y-axis of a Cartesian coordinate system) away from the first reference area, in particular from a transverse edge of the first reference area. The second leg of the first partial structure can run along a transverse axis (or along an x-axis of the Cartesian coordinate system).

[0017] Correspondingly, the second partial structure can have a first leg and a second leg, which together form an L-shape. The first leg can be shorter than the second leg. The first leg of the second partial structure can extend, in particular perpendicularly, along the longitudinal axis away from the first reference area, in particular from the transverse edge of the first reference area.

[0018] The second leg of the first substructure can extend, in particular perpendicular to the first leg of the first substructure, along the transverse axis (or along the x-axis of the Cartesian coordinate system) to the second substructure. Similarly, the second leg of the second substructure can extend, in particular perpendicular to the first leg of the second substructure, along the transverse axis to the first substructure. The second legs of the two substructures can run parallel to each other.

[0019] The first L-shaped substructure and the second L-shaped substructure can thus be arranged relative to one another such that together they have a U-shape. In this way, a multi-band loop antenna can be provided in a particularly efficient and compact manner. The second leg of the first substructure can adjoin the second leg of the second substructure in the coupling region. Furthermore, the second leg of the first substructure and the second leg of the second substructure can run parallel to one another, in particular in the coupling region. Furthermore, a part of the second leg of the first substructure and a part of the second leg of the second substructure can run directly next to one another in the coupling region and be spaced from one another by an electrically insulating (non-conductive) coupling gap.In other words, the second leg of the first partial structure and the second leg of the second partial structure can be arranged offset from one another along the longitudinal axis in the coupling region and overlapping one another along the transverse axis.

[0020] In a preferred example, the part of the second leg of the first substructure and the part of the second leg of the second substructure that run directly adjacent to one another in the coupling region each correspond to 30% or more, in particular 50% or more, of the leg length of the respective second leg. Optionally, 80% or more, in particular 90% or more, of the leg length of the second leg of the second substructure and 40% or more of the leg length of the second leg of the first substructure can run directly adjacent to one another (and overlap along the transverse axis). This allows a particularly reliable capacitive coupling to be formed between the substructures.

[0021] Parts of the second legs of the two substructures can thus together form a capacitor for capacitive coupling of the two substructures in order to provide a multi-band loop antenna in an efficient and compact manner.

[0022] The first leg of the first substructure and the first leg of the second substructure can each extend (along the longitudinal axis) toward a specific (transverse) edge of the circuit board. The antenna can be configured such that the second leg of the first substructure is positioned closer to the (transverse) edge of the circuit board in the coupling region than the second leg of the second substructure. In particular, at least a portion of the second leg (or the entire second leg) of the second substructure can be shielded from the (transverse) edge of the circuit board by a portion of the second leg of the first substructure. The second substructure can thus be positioned at a relatively large distance (compared to the first substructure) from the (transverse) edge of the circuit board.In this way, the sensitivity of the antenna can be further reduced, especially if the second substructure is designed for a (second) frequency range with higher frequencies than the first substructure.

[0023] The electrically non-conductive coupling gap between the second leg of the second substructure and the second leg of the first substructure preferably has a gap width that corresponds to 50% or more of the width of the second leg of the second substructure and / or the width of the second leg of the first substructure. Thus, a relatively wide coupling gap can be provided between the second legs of the first and second substructures. This can reduce the sensitivity of the antenna to manufacturing tolerances.

[0024] The first and / or second substructures can have a width that is increased relative to the leg width of the legs in a transition region between the legs of the respective substructure (particularly at the point where the two legs of the respective substructure are connected to each other). By increasing the width of a substructure in the transition region, the bandwidth of the frequency range of the respective substructure can be increased.

[0025] The legs of the first substructure can have a total length that depends on the first resonant frequency. In particular, the first substructure can be designed as a λ / 4 radiator with respect to the first resonant frequency. Alternatively or additionally, the (to be achieved) first resonant frequency can depend on the total length of the legs of the first substructure and on at least one property, in particular the capacitance, of the coupling region between the first substructure and the second substructure.

[0026] The legs of the second substructure can have a total length that depends on the second resonant frequency. In particular, the second resonant frequency (to be achieved) can depend on the total length of the legs of the second substructure and on at least one property, in particular the capacitance, of the coupling region between the first substructure and the second substructure. The different frequency ranges of the multi-band loop antenna can thus be precisely defined by the total length of the legs and / or the design of the coupling region.

[0027] The first reference region may have a channel-shaped (non-conductive) recess that extends from the transverse edge of the reference region and / or from the first leg of the second substructure. The feed line of the antenna may extend from the first leg of the second substructure within the channel-shaped recess (as a (straight-line) extension of the first leg of the second substructure) away from the second substructure to the feed point of the antenna.

[0028] The channel-shaped recess and the feed line can extend perpendicular to the transverse edge of the reference region in a first section. Furthermore, the channel-shaped recess and the feed line can extend parallel to the transverse edge of the reference region in a second section directly adjacent to the first section. Furthermore, the channel-shaped recess and the feed line can extend perpendicular to the transverse edge of the reference region and away from the second substructure in a third section directly adjacent to the second section. The channel-shaped recess and the feed line can each have right-angled transitions between the individual sections.

[0029] The channel-shaped recess and the feed line can thus have a path that includes several consecutive straight sections, each running perpendicular to each other. This allows the requirements of a Wi-Fi 6E antenna to be met in a particularly efficient and reliable manner.

[0030] The first leg of the first partial structure can extend from a first point on the transverse edge of the first reference region along (and parallel to) the longitudinal axis away from the transverse edge of the first reference region. In a corresponding manner, the first leg of the second partial structure can extend at a second point on the transverse edge of the first reference region along (and parallel to) the longitudinal axis away from the transverse edge of the first reference region. Furthermore, the first reference region can have a longitudinal edge at a third point on the transverse edge of the first reference region, which extends along (and parallel to) the longitudinal axis away from the transverse edge of the first reference region (up to the transverse edge of the printed circuit board).

[0031] The first, second, and third locations can be arranged one behind the other along the transverse edge of the first reference area and / or along the transverse axis. The first location can be arranged on a longitudinal edge of the circuit board. Furthermore, the first location, the second location, and the third location can be arranged at the same height along the longitudinal axis (i.e., without offset from one another along the transverse axis). Furthermore, the second location is preferably arranged between the first location and the third location. This allows for particularly robust feeding of the antenna.

[0032] As already explained above, the multi-band loop antenna has an electrically conductive second layer of the circuit board. In particular, the multi-band loop antenna has an electrically conductive second reference region on the second layer of the circuit board (wherein the second reference region can be at ground potential). The second reference region and the first reference region can be arranged to overlap one another at least partially or completely. Furthermore, the first reference region and the second reference region (apart from the channel-shaped recess for the antenna feed line) can be of the same design and / or dimension. The second reference region on the second layer can be electrically conductively connected to the first reference region on the first layer via one or more vias (i.e. via one or more electrical lines).By providing a second reference range, the sensitivity of the multi-band loop antenna to environmental changes can be further reduced.

[0033] The transverse edge of the first reference region and a corresponding transverse edge of the second reference region can run parallel to each other. The distance between the transverse edge of the first reference region and the transverse edge of the second reference region can correspond to the vertical distance between the first layer and the second layer (along the z-axis of the Cartesian coordinate system) and / or exceed the vertical distance between the first layer and the second layer by a maximum of 10%. In other words, the transverse edges of the two reference regions can be arranged directly above one another (at least in some regions) on different layers of the circuit board. This can apply correspondingly to the longitudinal edges of the two reference regions. In this way, a multi-band loop antenna can be provided that can be used in a particularly flexible manner in different environments.

[0034] As already explained above, the first substructure can have a transition region in a transition between the first leg and the second leg of the first substructure, in which the width of the first leg (along the transverse axis) increases smoothly, in particular linearly, from a first width to a second width. The second width can, for example, be larger than the first width by a factor of 2 to 2.5.

[0035] The transition region can begin at a first distance along the longitudinal axis from the transverse edge of the first reference region and end at a second distance along the longitudinal axis from the transverse edge of the first reference region in the second leg of the first substructure. By providing such a transition region, the bandwidth of the first frequency range can be adjusted (in particular, broadened).

[0036] According to a further aspect, an electrical device, in particular a domestic appliance or a household appliance, is described which comprises a communication unit for wireless communication (in particular via WLAN), wherein the communication unit has the multi-band loop antenna described in this document.

[0037] It should be noted that the devices and systems described in this document can be used both alone and in combination with other devices and systems described in this document. Furthermore, any aspects of the devices and systems described in this document can be combined in a variety of ways. In particular, the features of the claims can be combined in a variety of ways.

[0038] The invention is described in more detail below using exemplary embodiments.

[0039] Figure 1a shows the upper or first outer layer of a circuit board with an antenna;

[0040] Figure 1b shows the lower layer or the second outer layer of a printed circuit board;

[0041] Figure 1c shows a cross-section through a circuit board with an antenna;

[0042] Figures 2a and 2b show exemplary dimensions of the first and second layers of the printed circuit board antenna; and

[0043] Figure 3 shows an example frequency response of a printed circuit board antenna.

[0044] As stated at the beginning, this document addresses the provision of a (dual-band) antenna that can be efficiently integrated onto differently dimensioned and / or designed circuit boards and / or into different environments, and that features at least one extended frequency band. The (dual-band) antenna is specifically designed for WLAN (Wireless Local Area Network) 6E radio communication in the 2.4 GHz and 5-6 GHz frequency bands.

[0045] Figures 1a and 1b show an exemplary antenna 100 integrated on a circuit board 150. In particular, Fig. 1a shows the (electrically conductive) upper (first) layer 151 of the circuit board 150, and Fig. 1b shows the (electrically conductive) lower (second) layer 152 of the circuit board. As shown in Fig. 1c, one or more dielectric layers 130 and, if appropriate, one or more (electrically conductive) intermediate layers (not shown) are located between the upper (i.e., first) layer 151 and the lower (i.e., second) layer 152. The electrically conductive layers 151, 152 can comprise a layer of metal, in particular copper. The metal can be removed (e.g., etched away) in partial regions of the layers 151, 152 in order to form different electrically conductive partial regions within a layer 151, 152, wherein the partial regions can be at least partially electrically insulated from one another.

[0046] The first layer 151 has an electrically conductive antenna structure that forms a magnetic antenna or a loop antenna. The antenna structure has a first (L-shaped) substructure 110, which is designed as an antenna for a first frequency or for a first frequency range (approximately 2.3-2.6 GHz). For this purpose, the legs 111, 112 of the first L-shaped substructure 110 can together have a specific total length to form a λ / 4 radiator for the first frequency range.

[0047] The antenna structure further comprises a second (L-shaped) substructure 120, which is designed as an antenna for a second frequency or for a second frequency range (approximately 4.7-7 GHz). For this purpose, the legs 121, 122 of the second L-shaped substructure 120 can together have a specific total length to form a λ / 4 radiator for the second frequency range (optionally in combination with a property, in particular the capacitance, of the coupling region 108 between the two substructures 110, 120).

[0048] The two L-shaped partial structures 110, 120 are arranged on the first layer 151 of the printed circuit board 150 such that the partial structures 110, 120, together with the reference region 105, form a loop on the first layer 151. In particular, the first leg 111 of the first partial structure 110 can extend away from the reference region 105 (in particular perpendicularly from the transverse edge 161 of the reference region 105 along the y-axis (i.e., the longitudinal axis) of the Cartesian coordinate system). The second leg 112 of the first partial structure 110 can then run perpendicular to the first leg 111 of the first partial structure 110 (and thus parallel to the transverse edge 161 of the reference region 105). In a corresponding manner, the first leg

[0049] 121 of the second substructure 120 extend away from the reference area 105 (in particular perpendicularly from the transverse edge 161 of the reference area 105 along the y-axis (ie the longitudinal axis) of the Cartesian coordinate system). The second leg

[0050] 122 of the second partial structure 120 can then run perpendicular to the first leg 121 of the second partial structure 120 (and thus parallel to the transverse edge 161 of the reference area 105).

[0051] The second legs 112, 122 of the two substructures 110, 120 can run parallel to each other in the coupling region 108, with a coupling gap 102 located between the second legs 112, 122 of the two substructures 110, 120. The gap width of the gap 102 and / or the length of the overlap of the second legs 112, 122 of the two substructures 110, 120 can be selected to provide an optimized compromise between the strongest possible capacitive coupling of the two substructures 110, 120 on the one hand and the strongest possible selectivity and / or delimitation of the two frequency ranges on the other. Alternatively or additionally, the gap width and / or the length of the gap 102 can be selected or specified to set the second resonant frequency for the second frequency range.

[0052] The first leg 111 of the first partial structure 110 is electrically conductively connected to the reference region 105 (in particular to the transverse edge 161 of the reference region 105).

[0053] The frequency selectivity of the respective frequency range can be adjusted or adapted by adjusting the leg width of the legs 111, 112, 121, 122 of the substructures 110, 120. Reducing the leg width typically reduces the bandwidth of a frequency range, while increasing the leg width 106 increases the bandwidth of the frequency range.

[0054] Alternatively or additionally, a wider (compared to the leg width) (electrically conductive) transition region 113 can be arranged at the transition between the two legs 111, 112 of a substructure 110. By using a transition region 113 with an increased width, the bandwidth of the frequency range can be increased.

[0055] The antenna 100 can have a reference region 155 on the second layer 152 of the circuit board 150, which can be arranged directly opposite the reference region 105 of the first layer 151. The two reference regions 105, 155 can be electrically connected to one another via electrically conductive vias or through-holes 131.

[0056] Thus, in conjunction with Figures 1a and 1b, an antenna 100 is described that has L-antennas as substructures 110, 120. An L-antenna is an antenna in the shape of the letter "L." By interleaving two L-antennas 110, 120, it is possible (together with the reference region 105) to form a loop antenna that has two resonant frequencies. The capacitive coupling between the two L-antennas 110, 120 in the coupling region 108 makes it possible to adjust the second resonant frequency of the antenna 100 (for the second frequency range).

[0057] The reference region 105 of the first layer 150 has a channel-shaped recess 117, which extends from the transverse edge 161 of the reference region 105 (along the y-axis) away from the transverse edge 161 of the reference region 105 and / or from the second partial structure 120. The channel-shaped recess 117 has differently aligned sections, in particular

[0058] • a first section extending from the transverse edge 161 of the reference area 105 along (and parallel to) the y-axis (away from the transverse edge 161 of the reference area 105 and / or the second substructure 120);

[0059] • a subsequent second section extending along (and parallel to) the x-axis; and

[0060] • a subsequent third section extending along (and parallel to) the y-axis (away from the transverse edge 161 of the reference region 105 and / or the second substructure 120).

[0061] An electrically conductive feed line 115 runs within the channel-shaped recess 117 (in a manner corresponding to the course of the channel-shaped recess 117), which is electrically conductively connected to the second partial structure 120 at the transverse edge 161 of the reference region 105 and which has a feed point 107 at the opposite end for coupling or decoupling a signal into or out of the antenna 100.

[0062] The input and output of RF signals from the antenna 100 can thus be effected via the second substructure 120, whereby a particularly robust antenna for WLAN 6E can be provided.

[0063] Figures 2a and 2b show exemplary dimensions of the antenna 100 shown in Figures 1a to 1c. In particular, Figure 2a (for the first layer 151) shows along the x-axis:

[0064] • the length 201 of the second section of the channel-shaped recess 117 and / or the feed line 115;

[0065] • the width 202 of the channel-shaped recess 117; • the distance 203 between the first leg 111 of the first partial structure 110 and the first leg 121 of the second partial structure 120;

[0066] • the width 204 of the first leg 111 of the first partial structure 110 (before the widening in the transition area 113);

[0067] • the distance 205 of the first leg 121 of the second partial structure 120 from the reference area 105 (in particular from the longitudinal edge 162 of the reference area 105);

[0068] • the distance 206 of the second leg 112 of the first partial structure 110 from the reference area 105 (in particular from the longitudinal edge 162 of the reference area 105);

[0069] • the length 207 of the second leg 112 of the first substructure 110 (starting from the end of the spread of the first leg 111 of the first substructure 110 in the transition region 113);

[0070] • the total length 208 of the second leg 112 of the first partial structure 110 (starting from the outer longitudinal edge of the first leg 111 of the first partial structure 110);

[0071] • the total length 209 of the second leg 122 of the second partial structure 120 (starting from the outer longitudinal edge of the first leg 121 of the second partial structure 120);

[0072] • the width 210 of the first leg 121 of the second substructure 120;

[0073] • the width 211 of the first leg 111 of the first substructure 110 (at the end of the widening in the transition region 113); and / or

[0074] • the length 212 of the coupling region 108;

[0075] Furthermore, Figure 2a (for the first layer 151) shows along the y-axis:

[0076] • the length 221 of the third section of the channel-shaped recess 117 and / or the feed line 115;

[0077] • the length 222 of the first section of the channel-shaped recess 117 and / or the feed line 115;

[0078] • the length 223 of the first leg 121 of the second substructure 120;

[0079] • the length 224 of the first leg 111 of the first substructure 110;

[0080] • the distance 225 of the beginning of the transition region 113 from the transverse edge 161 of the reference region 105; • the width 226 of the second leg 112 of the first partial structure 110;

[0081] • the width 227 of the coupling gap 102 between the second leg 122 of the second substructure 120 and the second leg 112 of the first substructure 110; and / or

[0082] • the width 228 of the second leg 122 of the second substructure 120.

[0083] Furthermore, Figure 2b shows (for the second layer 152):

[0084] • the length 241 of the transverse edge 161 of the first and / or second reference area 105, 155; and / or

[0085] • the length 242 of the longitudinal edge 162 of the first and / or second reference area 105, 155.

[0086] Preferred values ​​of the above dimensions of the antenna 100 (in particular for an antenna 100 for the frequency bands 2.2 - 2.7 GHz and 4.8 - 7.0 GHz) are (each in mm and possibly with a possible deviation of up to ±10%):

[0087] • Dimension 201: 7.34; and / or

[0088] • Dimension 202: 1.1015; and / or

[0089] • Dimension 203: 11.1617; and / or

[0090] • Dimension 204: 2.5842; and / or

[0091] • Dimension 205: 9.1979; and / or

[0092] • Dimension 206: 9.5727; and / or

[0093] • Dimension 207: 8.5875; and / or

[0094] • Dimension 208: 13.8251; and / or

[0095] • Dimension 209: 7.0932; and / or

[0096] • Dimension 210: 0.4540; and / or

[0097] • Dimension 211: 5.2376; and / or

[0098] • Dimension 212: 6.6392; and / or

[0099] • Dimension 221: 3.4102; and / or

[0100] • Dimension 222: 3.0523; and / or

[0101] • Dimension 223: 4.4580; and / or

[0102] • Dimension 224: 5.5856; and / or

[0103] • Dimension 225: 2.9323; and / or

[0104] • Dimension 226: 1.8863; and / or • Dimension 227: 1.1276; and / or

[0105] • Dimension 228: 0.9324; and / or

[0106] • Dimension 241: 23.3978; and / or

[0107] • Dimension 242: 7.4719.

[0108] The printed circuit board 150 can, for example, have a thickness of 1.5 mm. The above-mentioned

[0109] Values ​​can vary by up to ±10% (especially to tune the resonance frequencies). Furthermore, the values ​​can be scaled by a common factor F if necessary.

[0110] Fig. 3 shows an exemplary frequency response 300 with a resonance frequency in the first frequency range 301 and another resonance frequency in the second frequency range 302.

[0111] The antenna 100 described in this document can absorb possible fluctuations in the environment of the antenna 100 (with or without plastic) and can make the input impedance of the antenna 100 virtually independent of the environmental conditions of the antenna 100. Furthermore, the described antenna 100 has a relatively small footprint.

[0112] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and figures are intended only to illustrate the principle of the proposed devices and systems.

Claims

PATENT CLAIMS 1) Multi-band loop antenna (100) comprising - a first, electrically conductive, L-shaped substructure (110) on a first layer (151) of a printed circuit board (150); wherein the first substructure (110) is designed for a first resonant frequency; - a second, electrically conductive, L-shaped substructure (120) on the first layer (151) of the printed circuit board (150); wherein the second substructure (120) is designed for a second resonant frequency; wherein the first substructure (110) and the second substructure (120) are capacitively coupled to one another in a coupling region (108); - an electrically conductive first reference region (105); wherein the first partial structure (110) and the second partial structure (120) are arranged on the first layer (151) of the printed circuit board (150) such that they form a loop together with the first reference region (105); wherein the first partial structure (110) and the second partial structure (120) each have a first leg (111, 121), each extending along a longitudinal axis away from a transverse edge (161) of the first reference region (105), and each have a second leg (112, 122), each extending along a transverse axis parallel to the transverse edge (161) of the first reference region (105); and - a feed line (115) which is electrically conductively coupled to the second substructure (120). 2) Multi-band loop antenna (100) according to claim 1, wherein - the first reference area (105) has a channel-shaped recess (117) which extends from the transverse edge (161) of the first reference area (105) away from the second partial structure (120); and - the feed line (115) extends from the first leg (121) of the second partial structure (120) within the channel-shaped recess (117) away from the second partial structure (120) to a feed point (107) of the antenna (100). 3) Multi-band loop antenna (100) according to claim 2, wherein the channel-shaped recess (117) and the feed line (115) extend in a first section perpendicular to the transverse edge (161) of the first reference area (105). 4) Multi-band loop antenna (100) according to claim 3, wherein the channel-shaped recess (117) and the feed line (115) - extend parallel to the transverse edge (161) of the first reference area (105) in a second section directly adjoining the first section; and - in a third section directly adjoining the second section, extend perpendicular to the transverse edge (161) of the first reference region (105) and away from the second partial structure (120). 5) Multi-band loop antenna (100) according to one of the preceding claims, wherein - the first leg (111) of the first partial structure (110) extends at a first location of the transverse edge (161) of the first reference region (161) along the longitudinal axis away from the transverse edge (161) of the first reference region (105); - the first leg (121) of the second partial structure (120) extends at a second location of the transverse edge (161) of the first reference region (161) along the longitudinal axis away from the transverse edge (161) of the first reference region (105); - the first reference region (105) has, at a third location of the transverse edge (161) of the first reference region (161), a longitudinal edge (162) which extends along the longitudinal axis away from the transverse edge (161) of the first reference region (105); and - the second position is located between the first position and the third position. 6) Multi-band loop antenna (100) according to claim 5, wherein the first location is arranged on a longitudinal edge of the circuit board (150). 7) Multi-band loop antenna (100) according to one of claims 5 to 6, wherein the first location, the second location and the third location are arranged at the same height along the longitudinal axis. 8) Multi-band loop antenna (100) according to one of the preceding claims, wherein - the second leg (112) of the first partial structure (110) adjoins the second leg (122) of the second partial structure (120) in the coupling region (108); and / or - the second leg (112) of the first partial structure (110) and the second leg (122) of the second partial structure (120) run parallel to one another, in particular in the coupling region (108); and / or - at least a part of the second leg (112) of the first partial structure (110) and at least a part of the second leg (122) of the second partial structure (120) run directly next to one another in the coupling region (108) and are spaced from one another by an electrically non-conductive coupling gap (102). 9) Multi-band loop antenna (100) according to claim 8, wherein the part of the second leg (112) of the first partial structure (110) and the part of the second leg (122) of the second partial structure (120) which run directly next to one another in the coupling region (108) each correspond to 30% or more, in particular 50% or more, of a leg length (208, 209) of the respective second leg (112, 122). 10) Multi-band loop antenna (100) according to claim 9, wherein 90% or more of the leg length (209) of the second leg (122) of the second substructure (120) is arranged in the coupling region (108) directly adjacent to the second leg (112) of the first substructure (120). 11) Multi-band loop antenna (100) according to one of claims 8 to 10, wherein - the first leg (111) of the first partial structure (110) and the first leg (121) of the second partial structure (120) extend towards a transverse edge of the printed circuit board (150); and - the second leg (112) of the first partial structure (110) is arranged in the coupling region (108) closer to the transverse edge of the printed circuit board (150) than the second leg (122) of the second partial structure (120). 12) Multi-band loop antenna (100) according to one of claims 8 to 11, wherein the electrically non-conductive coupling gap (102) between the second leg (122) of the second substructure (120) and the second leg (112) of the first substructure (110) has a gap width (227) which corresponds to 50% or more of a width (226, 228) of the second leg (122) of the second substructure (120) and / or the second leg (112) of the first substructure (110). 13) Multi-band loop antenna (100) according to one of the preceding claims, wherein - the first partial structure (110) has a transition region (113) between the first leg (111) and the second leg (112) of the first partial structure (110), in which a width (204, 208) of the first leg (111) increases smoothly, in particular linearly, from a first width (204) to a second width (208); and - the transition region (113) begins at a first distance (225) along the longitudinal axis from the transverse edge (161) of the first reference region (105) and ends at a second distance (224) along the longitudinal axis from the transverse edge (161) of the first reference region (105) in the second leg (112) of the first partial structure (110). 14) Multi-band loop antenna (100) according to one of the preceding claims, wherein the first partial structure (110), in particular the first leg (111) of the first partial structure (110), is electrically conductively connected to the first reference region (105). 15) Household appliance comprising a communication unit with a multi-band loop antenna (100) according to one of the preceding claims.

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