Abstract
The present invention provides a dual-polarized radiating element comprising a feeding arrangement and four dipole arms. The feeding arrangement comprises four slots, which extend from a periphery towards a center of the feeding arrangement and which are arranged at regular angular intervals forming a first angular arrangement. The four dipole arms extend outwards from the feeding arrangement and are arranged at regular angular intervals to form a second angular arrangement. The second angular arrangement of the four dipole arms is rotated with respect to the first angular arrangement of the four slots.
Claims
1. A dual-polarized radiating element, comprising: a feeding arrangement comprising four slots, the four slots extending from a periphery of the feeding arrangement towards a center of the feeding arrangement and being arranged at regular angular intervals so as to form a first angular arrangement; and four dipole arms, the four dipole arms extending outwards from the feeding arrangement and being arranged at regular angular intervals so as to form a second angular arrangement, wherein the second angular arrangement of the four dipole arms is rotated with respect to the first angular arrangement of the four slots, and wherein at least a part of each dipole arm extends upwards and/or downwards with respect to a feeding arrangement plane.
2. The dual-polarized radiating element according to claim 1, wherein the four slots and the four dipole arms, respectively, are arranged at 90° intervals, and the second angular arrangement of the four dipole arms is rotated by 45° with respect to the first angular arrangement of the four slots.
3. The dual-polarized radiating element according to claim 1, wherein adjacently arranged slots extend perpendicular to one another while non-adjacently arranged slots extend in-line with one another such that the four slots form two in-line extending slot pairs, and wherein the two in-line extending slot pairs define two orthogonal polarizations of the dual-polarized radiating element.
4. The dual-polarized radiating element according to claim 1, wherein each dipole arm is terminated at an outer end by a flap.
5. The dual-polarized radiating element according to claim 1, further comprising a parasitic director arranged above the feeding arrangement.
6. The dual-polarized radiating element according to claim 5, wherein the parasitic director extends outwards from the feeding arrangement less than each of the four dipole arms, and/or wherein each dipole arm comprises an outer part extending upwards with respect to a feeding arrangement plane, and the parasitic director is arranged in a recess defined within the four outer parts.
7. The dual-polarized radiating element according to claim 1, wherein the feeding arrangement comprises four first transmission lines, each first transmission line crossing one of the four slots.
8. The dual-polarized radiating element according to claim 7, wherein two first transmission lines crossing non-adjacent slots are combined into one second transmission line.
9. The dual-polarized radiating element according to claim 8, wherein the feeding arrangement comprises a printed circuit board (PCB) on which the four first transmission lines are combined into two second transmission lines, or wherein the radiating element comprises a PCB arrangement extending from a bottom surface of the feeding arrangement, on which PCB arrangement the four transmission lines are combined into two second transmission lines.
10. The dual-polarized radiating element according to claim 1, further comprising four flaps extending from the feeding arrangement, wherein each one of the four slots is extended on one of the four flaps.
11. The dual-polarized radiating element according to claim 1, wherein the feeding arrangement comprises a printed circuit board (PCB), on which the four slots are arranged and to which the four dipole arms are connected.
12. The dual-polarized radiating element according to claim 10, wherein the four flaps are connected to a printed circuit board (PCB) and are bent upwards with respect to a feeding arrangement plane and are arranged in between the four dipole arms, respectively.
13. The dual-polarized radiating element according to claim 12, wherein the four flaps and the four dipole arms are formed by four separate integral elements, each integral element comprising one dipole arm and two sub-flaps, and wherein each flap is formed by two sub-flaps of adjacent integral elements.
14. The dual-polarized radiating element according to claim 13, wherein each integral element is soldered at a respective dipole arm with one soldering point to the PCB and at each of two respective sub-flaps with one soldering point to the PCB.
15. The dual-polarized radiating element according to claim 1, wherein the feeding arrangement comprising a metal sheet, and wherein the four slots are cut outs in the metal sheet and the four dipole arms are formed by the metal sheet.
16. The dual-polarized radiating element according to claim 10, further comprising a metal sheet including the four flaps, the four flaps being bent upwards or downwards with respect to a feeding arrangement plane and being arranged in between the four dipole arms, respectively.
17. An antenna, comprising: at least one dual-polarized radiating element according to claim 1, wherein two dipole arms of the at least one dual-polarized radiating element extend along a longitudinal axis of the antenna, and wherein two dipole arms of the at least one dual-polarized radiating element extend along a lateral axis of the antenna.
18. The antenna according to claim 17, wherein each slot of the at least one dual-polarized radiating element extends at an angle of 45° with respect to the longitudinal axis of the antenna.
19. The antenna according to claim 17, further comprising: a plurality of additional first column dual-polarized radiating elements arranged along the longitudinal axis of the antenna in at least a first column, and a plurality of additional second column radiating elements arranged along the longitudinal axis of the antenna in at least two second columns disposed side-by-side the at least one first column, wherein dipole arms of the first column dual-polarized radiating elements extend between the second column radiating elements in the at least two second columns.
20. The antenna according to claim 19, wherein the antenna is configured for multiband operation, and wherein the first column dual-polarized radiating elements are configured to radiate in a first frequency band, and wherein the second column radiating elements are configured to radiate in a second frequency band.
21. The antenna according to claim 17, wherein a plurality of additional dual-polarized radiating elements are interleaved with a plurality of second additional radiating elements that form a massive Multiple Input Multiple Output (mMIMO) array.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1) The above-described aspects and implementation forms of the present invention will be explained in the following description of specific embodiments in relation to the enclosed drawings in which:
(2) FIG. 1 shows a radiating element according to an embodiment of the present invention;
(3) FIG. 2 shows a radiating element according to an embodiment of the present invention;
(4) FIG. 3 compares current-density plots of a radiating element according to an embodiment of the present invention with a conventional square-shaped radiating element;
(5) FIG. 4 shows a device according to an embodiment of the present invention;
(6) FIG. 5 shows the device of FIG. 4 in a side view;
(7) FIG. 6 shows a device according to an embodiment of the present invention;
(8) FIG. 7 shows a device according to an embodiment of the present invention;
(9) FIG. 8 shows a dielectric support structure for a device according to an embodiment of the present invention;
(10) FIG. 9 shows a device according to an embodiment of the present invention;
(11) FIG. 10 shows a device according to an embodiment of the present invention;
(12) FIG. 11 shows a device according to an embodiment of the present invention;
(13) FIG. 12 shows a VSWR of a radiating element according to an embodiment of the present invention;
(14) FIG. 13 shows a radiation pattern of a radiating element according to an embodiment of the present invention;
(15) FIG. 14 shows a radiating element according to an embodiment of the present invention working in a multiband antenna architecture;
(16) FIG. 15 shows an antenna according to an embodiment of the present invention;
(17) FIG. 16 shows a device according to an embodiment of the present invention;
(18) FIG. 17 shows a device according to an embodiment of the present invention;
(19) FIG. 18 shows a device according to an embodiment of the present invention;
(20) FIG. 19 shows parts of a device according to an embodiment of the present invention;
(21) FIG. 20 shows a device according to an embodiment of the present invention;
(22) FIG. 21 shows a radiating element according to an embodiment of the present invention working in a multiband antenna architecture;
(23) FIG. 22 shows a radiating element according to an embodiment of the present invention working in a multiband antenna architecture; and
(24) FIG. 23 shows a radiating element according to an embodiment of the present invention working in a multiband antenna architecture integrated with a mMIMO array.
DETAILED DESCRIPTION OF EMBODIMENTS
(25) FIG. 1 shows a dual-polarized radiating element 100 according to an embodiment of the present invention. The radiating element 100 comprises a feeding arrangement 101, and four dipole arms 103. It further exhibits a specific angular arrangement of its components.
(26) The feeding arrangement 101 comprises four slots 102, which extend from a periphery towards a center of the feeding arrangement 101, and which are arranged at regular angular intervals 104, which forms a first angular arrangement. In particular, two adjacent slots 102 in the first angular arrangement are arranged with an angle α in between. Further, each of the slots 102 extends from the periphery of the feeding arrangement 101 to a center portion of the feeding arrangement 101, preferably in a radial manner.
(27) The four dipole arms 103 extend outwards from the feeding arrangement 101, and are arranged at regular angular intervals 105, which forms a second angular arrangement. In particular, two adjacent dipole arms 103 in the second angular arrangement are arranged with an angle θ in between. A dipole arm 103 is a structural element extending from the feeding arrangement 101, with a length in extension direction that is larger than its width. Preferably, each of the dipole arms 103 has further a width that is smaller than the width of the feeding arrangement 101 side, from which it extends.
(28) The second angular arrangement of the four dipole arms 103 is rotated 106 with respect to the first angular arrangement of the four slots 102, particularly by an angle Φ 106.
(29) FIG. 2 shows another radiating element 100 according to an embodiment of the present invention, which builds on the radiating element 100 shown in FIG. 1. Identical elements in these two FIGS. 1 and 2 are provided with the same reference signs.
(30) In particular, the radiating element 100 of FIG. 2 has the four slots 102 and four dipole arms 103, which are here respectively arranged at 90° intervals each. Further, the angular arrangements of the dipole arms 103 and the slots 102 are here rotated with respect to each other by 45°. Accordingly, the radiating element 100 extends with its dipole arms 103 mainly in two perpendicular directions (referred to as vertical and horizontal directions, respectively), but the polarizations of the radiating element 100 will lie at ±45° to these horizontal and vertical directions. FIG. 2 specifically shows that adjacently arranged slots 102 extend perpendicular to another, and that non-adjacently arranged slots 102 extend in line with another in this radiating element 100. Thus, two in line extending slot pairs are defined.
(31) The two in line extending slot pairs define the two ±45° orthogonal polarizations of the dual-polarized radiating element 100, when it is operated. To this end, the radiating element 100 is fed in operation preferably like a conventional square dipole, whereby the four slots 102 of the feeding arrangement 101 are particularly fed symmetrically 2-by-2.
(32) FIG. 2 also shows that each of the four slots 102 ends in a symmetrically bent, more or less U-shaped slot 201. The purpose of the four slots 201 is to extend the total length of each of the four slots 102, particularly for impedance matching purposes. Since the length of the four slots 102 cannot be extended further to a center portion of the feeding arrangement 101 (due to a lack of space in the middle), they can only be extended to the sides and backwards. In order to thereby maintain the symmetry, the bent slot 201 preferably have the same pattern at both sides of a slot 102. This leads to the symmetrically bent slots 201, preferably the shown U-shaped ones.
(33) The feeding arrangement 101 shown in FIG. 2 comprises a PCB 205, and the four dipole arms 102 are soldered to the PCB 205 through soldering pins 206. The soldering pins 206 cross the PCB 205 from bottom to top. Capacitive coupling between the four dipole arms 102, and to the PCB 205, is possible. However, in this case the coupling area should be dimensioned accordingly, in order to achieve enough coupling. It should also be ensured that the distance between the dipole arms 102 and the PCB 205 is small and stable.
(34) Preferably, the dipole arms 102 do not extend only horizontally and vertically, but—as shown in FIG. 2—also in the third perpendicular dimension, i.e. along a z-axis. In other words, at least a part 203 of each dipole arm 102 preferably extends upwards and/or downwards with respect to the feeding arrangement plane in which the feeding arrangement is arranged 101. In FIG. 2, each dipole arm 103 extends upwards in a part 203. By extending in the z-axis, the dipole arms 102 can be made longer electrically, without increasing their footprint. Furthermore, also a distance to ground can be increased, which reduces the capacitance to ground, and therefore increases the working bandwidth. Most importantly, all these advantages come for free, because the total height of the radiating element 100 does not need to be increased. This is explained below with respect to FIG. 4.
(35) As further shown in FIG. 2, the dipole arms 102 are preferably terminated with flaps 204, which make the dipole arms 102 again electrically longer, without increasing their footprint. Preferably, as shown in FIG. 2, the flaps 204 are bent downwards. However, it is also possible to have upwards or downwards bent flaps 204, and even a bending of flaps 204 back towards the feeding arrangement 101 is possible. Examples of alternative flaps 204 will be provided with respect to other figures further below. Also described further below is an optional support 800 for the radiating element 100.
(36) FIG. 3 shows a comparison of simulations of a current-density plot in a radiating element 100 (left side) according to FIG. 2, and in a conventional square-shaped radiating element 300 (right side). In the conventional radiating element 300, most of the current is concentrated in slots 302 of a feeding arrangement 301, whereas in the radiating element 100 the dipole is reshaped in such a way, that the current flows horizontally and vertically instead. The horizontal and vertical components of the current are equal, and the combination generates the ±45° polarizations. This advantageously allows to maximize the surface efficiency of the radiating element 100, which means that practically the whole surface of the radiating element 100, i.e. both of the feeding arrangement 101 and the dipole arms 103, contributes to the radiation. The amount of metallic surface is thus optimized. In the conventional square-shaped radiating element 300, there is a big surface amount that practically does not contribute to the radiation. Nevertheless, its presence inside, for instance, a multiband antenna, will create shadows on and interference with other radiating elements working in different, especially in higher frequency bands.
(37) For the radiating element 100, the feeding of the slots 102 is, as for a conventional square dipole, but the current distribution corresponds more to a cross dipole. Therefore, advantages of both dipole kinds are combined, and the radiating element 100 has broadband characteristics, but at the same time a very small footprint.
(38) FIG. 4 shows another radiating element 100 according to an embodiment of the present invention. The radiating element 100 of FIG. 4 builds on the radiating element 100 shown in FIG. 3. Identical elements in these two FIGS. 3 and 4 are provided with the same reference signs. FIG. 4 shows a radiating element 100 that further comprises a parasitic director 401, which is preferably arranged above the feeding arrangement 101. The parasitic director 401 further helps to achieve the required bandwidth, and at the same time to minimize the dimensions of the radiating element 100.
(39) FIG. 5 shows a side view of the radiating element 100 that is shown in FIG. 4. In FIG. 5, it shows that preferably the parasitic director 401 extends outwards from the feeding arrangement 101 less than each one of the four dipole arms 103. Thus, the parasitic director 401 does not increase the width and length of the radiating element 100 in the horizontal and vertical directions, respectively. Further, additionally or optionally, each dipole arm 103 may comprise, as shown in FIG. 5, an outer part 203 that extends upwards with respect to the feeding arrangement plane. Then, the parasitic director 401 is preferably arranged in a recess 501, which is defined within the four outer parts 203. Thus, the parasitic director 401 does also not increase the height of the radiating element 100. Further, as mentioned above, the dipole arms 103 are extended electrically in length due to the parts 203, however, preferably not above the above plane of the parasitic director 401. The height of the radiating element 100 of FIG. 4 is, for example assuming an operating frequency band of 690-960 MHz, about 65 mm. That means, the height of the radiating element 100 is about 0.15λ at 690 MHz, and even below 0.15λ at 960 MHz, wherein λ is the wavelength corresponding to the respective frequencies. That is, it is a low profile radiating element 100.
(40) FIG. 6 shows another radiating element 100 according to an embodiment of the present invention in a bottom view. Elements shown in FIG. 6 and identical elements in the previous figures, are provided with the same reference signs. The PCB 205 carrying the feeding arrangement 101 and the slots 102, 201 is visualized transparent in FIG. 6, so that the crossings between the (feeding) transmission lines 601 and the slots 102 can be easily seen.
(41) FIG. 6 shows that the feeding arrangement 101 preferably further comprises four transmission lines 601, wherein each transmission line 601 crosses one of the four slots 102. The transmission lines 601 are preferably short-ended microstrip lines. The transmission lines 601 are particularly used for feeding the four slots 102, and are combined, in order to feed two non-adjacent slots 102 in an identical manner. This leads to the dual polarization of the radiating element 100. In FIG. 6, the combination of the four transmission lines 601 into two transmission lines 602 is carried out on a PCB arrangement 603. In particular, this PCB arrangement 603 extends from a bottom surface of the feeding arrangement 101. The PCB arrangement 603 may specifically extend orthogonally from the feeding arrangement 101. Because the four transmission lines 601 are combined into the two transmission lines 602, firstly a feeding signal can be transmitted from the PCB arrangement 603 to, for example, a PCB 205 of the feeding arrangement 101, and secondly the radiating element 100 can be grounded.
(42) For instance, a ground of the PCB arrangement 603 may be connected (e.g. soldered) to a ground of the feeding arrangement 101. The PCB arrangement 603 may also be connected to an additional PCB, which serves, for instance, as a transition between the radiating element 100 and a feeding network. Other implementations, like a direct connection to a phase shifter, or a direct connection to a coaxial cable, are also possible.
(43) FIG. 7 shows another radiating element 100 according to an embodiment of the present invention, in which the transmission lines 601 are combined into transmission lines 702 in a different manner than in FIG. 6. Nevertheless, identical elements in the two FIGS. 6 and 7 are provided with the same reference signs. In particular, in FIG. 7 the combination of the four transmission lines 601 into two transmission lines 702 is carried out on the feeding arrangement 101, particularly, on the PCB 205 of the feeding arrangement 101. Thereby, the number of total soldering points can be reduced, since only two signal paths are present, instead of four. Furthermore, slots in the center of the PCB 205 can be divided into four small slots, which offers advantages in terms of isolation between different frequency bands.
(44) FIG. 8 shows a dielectric support 800, onto which the radiating element 100 according to an embodiment of the present invention can be mounted. This is also indicated in the previous figures showing the radiating elements 100. The dielectric support 800 advantageously ensures mechanical stability of the radiating element 100, and ensures that a distance from the radiating element 100 to an antenna reflector, as well as a distance from a parasitic director 401 to the radiating element 100, is stably maintained. The dielectric support 800 may specifically comprise support feet 804, which also define a distance of the radiating element 100 to, for example, a feeding network or to the antenna reflector. Further, the support 800 can include support elements 802, in order to stably support the four dipole arms 102 of the radiating element 100. The support 800 can also comprise attachment means 803, which are configured to hold the feeding arrangement 101, and preferably the parasitic director 401.
(45) FIG. 9 shows a radiating element 100 according to an embodiment of the present invention. Elements in FIG. 9 and identical elements in the previous figures, are provided with the same reference signs. In FIG. 9 the feeding arrangement 101 of the radiating element 100 is made out of one single bent metal sheet together with the dipole arms 103, instead of comprising a PCB 205 and the four dipole arms 103 attached thereto. In particular, the feeding arrangement 101 comprises a metal sheet 901, wherein the four slots 102 are preferably cutouts in the metal sheet 901, and also the four dipole arms 103 are formed by the metal sheet 901. This has, for example, the advantage that the metal sheet 901 can be easily designed with four further flaps 902, which may be arranged in between the four dipole arms 102. The further flaps 902 may be bent upwards or downwards with respect to the feeding arrangement plane. Furthermore, the slots 102 may further extend along the flaps 902. Thereby, the extending slots 102 may actually divide each of the four flaps 902 into to two sub-flaps, as it is shown in FIG. 9. By means of the flaps 902, the slots 102 can be either be electrically extended without changing the size of the feeding arrangement 101, or the size of the feeding arrangement 101 can be reduced without reducing the length of the slots 102. In FIG. 9, the flaps 902 are bent downwards, and furthermore slightly back towards the feeding arrangement 101. However, the flaps 902 could also be bent upwards, in order to allow a better integration with an array of other radiating elements that are less high than the radiating element 100. Further, as shown in FIG. 9, also the dipole arms 103 can have additional bends, for instance, side flaps 903 for increasing the electrical width of the dipole arm 102. The side flaps 903 may be formed by bending the dipole arms 103 along their extension direction. The slots 102 can be fed by transmission lines on a PCB e.g. arranged below the metal sheet 901. In a further embodiment the slots 102 may be fed using a suitable cable feed e.g. arranged below the metal sheet 901.
(46) FIG. 10 shows yet another radiating element 100 according to an embodiment of the present invention, which builds for instance on the radiating element 100 shown in FIG. 2. Identical elements in these two FIGS. 2 and 10 are provided with the same reference signs. In FIG. 10, the flaps 204 terminating the dipole arms 103 are not only bent downwards, but also back towards the feeding arrangement 101. This provides further electrical length to the dipole arms 103. Further, the optional parasitic capacitor 401 is shown to be arranged above the feeding arrangement 101, and particularly within the extension length of the four dipole arms 103.
(47) FIG. 11 shows another radiating element 100 according to an embodiment of the present invention, which builds on the radiating element 100 shown in FIG. 1. Identical elements in these two FIGS. 1 and 11 are provided with the same reference signs. Here, in FIG. 11, the dipole arms 103 extend outwards from the feeding arrangement 101 and are terminated by upward bent flaps 204, respectively, for increasing their electrical length. Also, the optional PCB arrangement 603 extending from the feeding arrangement 101 is shown. The PCB arrangement 603 may serve also as mechanical support, for instance, instead of the support 800.
(48) Notably, with respect to the above-described radiating elements 100, the decision of whether terminating flaps 204 of the dipole arms 103 are bent upwards or downwards can be decided after a detailed optimization process of the radiating element 100. The decision can, for instance, depend on the arrangement of the radiating element 100 on an antenna, particularly together with other radiating elements arranged side-by-side the radiating element 100.
(49) FIGS. 12 and 13 show RF performance of the radiating element 100 according to an embodiment of the present invention. Specifically, the Voltage Standing Wave Ratio (VSWR) and the radiation pattern of the radiating element 100 are shown. FIG. 12 specifically shows that the VSWR is below 16.5 dB (1.35:1) from 690-960 MHz. FIG. 13 shows that the radiation pattern is symmetric, the 3 dB beamwidth is around 65 degree and the Cross-polar discrimination is above 10 dB in the range from +60 to −60 degree.
(50) FIG. 14 shows, how the radiating element 100 according to an embodiment of the present invention can advantageously be arranged in a multiband antenna architecture. At both sides of the radiating element 100, there are provided other radiating elements 1400, for instance, configured to work in a higher frequency band like in HB arrays. Due to the shape of the radiating element 100, a distance between the other radiating elements 1400 on either side of the radiating element 100 can be minimized, namely by arranging the other radiating elements 1400 nested with the dipole arms 103 that extend from the feeding arrangement 101 of the radiating element 100. Therefore, either the dimensions of the multiband antenna architecture can be reduced, or the number of HB arrays within the same dimensions of the architecture can be increased.
(51) FIG. 15 shows in this respect an antenna 1500 according to an embodiment of the present invention. The antenna 1500 comprises three columns of radiating elements, each column extending along a longitudinal axis 1501 of the antenna 1500. In particular, the radiating elements 100 are arranged in a first column 1504, which is located in between and side-by-side two second columns 1503 comprising the other radiating elements 1400. Preferably, the second columns 1503 are HB arrays, and the first column 1504 is an LB array. FIG. 15 again shows, how two of the dipole arms 103 of each radiating element 100 extend between two of the other radiating elements 1400 in the HB arrays, i.e. they extend along a lateral axis 1502 of the antenna 1500. The other two dipole arms 103 of each radiating element 100 extend along the longitudinal axis 1501 of the antenna 1500. This allows a very dense packing of the respective HB and LB arrays. However, as also desired, the radiation polarizations defined by the slots 102 of the radiating elements 100 are still ±45° with respect to the longitudinal axis 1501 of the antenna 1500.
(52) FIG. 16 shows another radiating element 100 according to an embodiment of the present invention, which builds on the radiating element 100 shown in FIG. 1. Identical elements in these two FIGS. 1 and 11 are provided with the same reference signs. Here, in FIG. 16, the radiating element comprises four further flaps 1600 extending from the feeding arrangement 101. In particular, the four flaps 1600 are connected to a PCB 205, and are preferably bent upwards with respect to the feeding arrangement plane. The four flaps 1600 are arranged in between the four dipole arms 103, respectively. Each one of the four slots 102 further extends along the flaps 1600, that means, it is electrically extended on one of the four flaps 1600. Thereby, each flap 1600 may be formed by two sub-flaps 1601 creating one slot extension, as it is shown in FIG. 16. Accordingly, the radiating element 1600 comprises in this case eight sub-flaps 1601.
(53) The radiating element 100 shown in FIG. 16 is particularly advantageous for integrating an array of many such radiating elements 100 with another array of other radiating elements 1400, for instance with a mMIMO array. This is due to the fact that the shown modifications of the radiating element 100 improve the isolation and squint of closely spaced mMIMO radiating elements 1400 in such a mMIMO array. For instance, the size of the PCB 205 can be reduced without sacrificing length of the slots 102, which is enabled by the flaps 1600 allowing to electrically extend the slots 102. The flaps 1600 are preferably folded upwards, in order to minimize the squint of the lower-lying mMIMO array.
(54) Furthermore, the size of the parasitic director 401 may also be minimized to minimize the radiating element 100 as a whole. Any loss of bandwidth that results from this size decrease of the parasitic director 401 can preferably be compensated by increasing at the same time the height of the radiating element 100. Additionally, in contrast to the parasitic director 401 shown in FIG. 4, 10 or 11, the shape of the parasitic director 401 may be changed. The parasitic director 401 shown in FIG. 16 does not have any flaps or arms extending from its central part. Preferably, the parasitic director 401 has an octagonal shape as it is shown in FIG. 16. Preferably, four sides of the octagonal parasitic director 401 are arranged at the same positions and at the same angular intervals of the second angular arrangement formed by the dipole arms 103. Preferably, the other four sides of the octagonal parasitic director 401 are arranged at the same positions and at the same angular intervals of the first angular arrangement formed by the four slots 102. Alternatively, however, the director 401 may also have a round shape, or a shape with more than eight sides.
(55) The radiating element 100 of FIG. 16 can be further optimized for integration with a mMIMO array by having preferably dipole arms 103 that are folded downwardly. That is, at least a part 204 of each dipole arm 103 extends downwards with respect to the feeding arrangement plane. Optionally, the dipole arms 103 are further bent back towards the feeding arrangement 101.
(56) FIG. 17 shows the radiating element 100 of FIG. 16 in a top view. The first and second angular intervals 105 and 106 of the four slots 102 and the four dipole arms 103, respectively, are shown, and the above-described preferred shape and orientation of the preferred octagonal parasitic director 401 is illustrated.
(57) FIG. 18 shows a radiating element according to an embodiment of the present invention, which builds on the radiating element 100 shown in FIG. 16. The radiating element 100 in FIG. 18 is shown without a parasitic director 401. The four slots 102 can thus be seen well, here they are provided on the PCB 205, and it can be seen how they extend onto the four flaps 1600. It can also be seen that each flap 1600 is preferably soldered with two soldering points 206 to the PCB 205. In particular, in case of the flaps 1600 being formed by sub-flaps 1601 creating the slot extensions, each sub-flap 1601 is preferably soldered with one soldering point 206 to the PCB 205 as shown in FIG. 18. Further, each dipole arm 103 is preferably soldered with one soldering point 206 to the PCB 205. These soldering points 206 improve the mechanical stability of the radiating element 100 and also electrical continuity is provided.
(58) FIG. 19 shows exemplary parts of a radiating element 100 according to an embodiment of the present invention, for instance, parts of the radiating element 100 of FIG. 18. Here in FIG. 19, each one of the four flaps 1600 is formed by two-sub flaps 1601. Further, the four dipole arms 103 and the four flaps 1600 are formed by four separate integral elements 1900. Each integral element is formed by one dipole arm 103 and two (opposing) sub-flaps 1601, particularly with one sub-flap 1601 being arranged on either side of the dipole arm 103. For instance, two metallic sub-flaps 1601 with a metallic dipole arm 103 in-between them may form one integral element 1900. The four integral elements 1900 are arranged such in the radiating element 100 that their diploe arms 103 are arranged at the regular intervals 105 forming the second angular arrangement, preferably that their dipole arms 103 are arranged at 90° intervals. Further, the four integral elements 1900 are arranged such in the radiating element 100 that two sub-flaps 1601 of two adjacent integral elements 1900 form one flap 1600 and accordingly create an extension for one of the four slots 102. Such a particular arrangement of integral elements 1900 is shown in FIG. 19.
(59) The four integral elements 1900 improve further the mechanical stability of the radiating element 100. Each integral element 1900 is preferably soldered at its dipole arm 103 with one soldering point 206 to the PCB 205, and at each of its two sub-flaps 1601 with one soldering point 206 to the PCB 205 for the best mechanical stability. However, it is also possible to form the four dipole arms 103 and the four flaps 1600, respectively, in a different manner. In particular, two sub-flaps 1601 forming one flap 1600 need not necessarily belong to two separate integral elements 1900, but could be formed by a single integral piece, like the flaps 902 shown in FIG. 9.
(60) FIG. 20 shows a radiating element 100 according to an embodiment of the present invention, which builds on the radiating element shown in FIG. 16. The further flaps 1600 and the extensions of the slots 102 on each of these flaps 1600 are well visible. Further, it can be seen that a PCB arrangement 603 may extend from the bottom surface of the feeding arrangement 101, particularly from the PCB 205. On the PCB arrangement 603 preferably four transmission lines 601 that are coming from the PCB 205 are combined into two transmission lines 602.
(61) FIG. 21 shows a radiating element 100 according to an embodiment of the present invention, which builds on the radiating element 100 of FIG. 16, and is working in a multiband antenna architecture. The radiating element 100 is arranged such that its dipole arms 103 extend between the other radiating elements 1400 that are arranged in at least two columns. Preferably, these other radiating elements 1400 form a mMIMO array. It can be seen that due to the fact that the radiating elements 100 comprises the upwards bent flaps 1600, wherein the flaps 1600 electrically extend each of the four slots 102, the form factor of the radiating elements 100 can be made much smaller. Therefore, the other radiating elements 1400 are less shadowed. Accordingly, the squint of the mMIMO array and its radiating elements is minimized.
(62) FIG. 22 shows a radiating element 100 according to an embodiment of the present invention working in a multiband antenna architecture with other radiating elements 1400. For purposes of illustration, a conventional, disc-shaped radiating element 2200 is shown in comparison to the radiating element 100, as it would be arranged if integrated with the array of other radiating elements 1400. It can be seen that the radiating element 100, due to its small footprint and its smarter space filling, results in a much lower shadowing effect on the other radiating elements 1400 than the conventional radiating element 2200.
(63) FIG. 23 shows a plurality of radiating elements 100 according to embodiments of the present invention working in a multiband antenna architecture integrated with a mMIMO array. The radiating elements 100 are preferably arranged in at least one column along the longitudinal axis 1501 or direction of the antenna 1500. In case of more than one column, these columns are separated along the lateral axis 1502 or direction of the antenna 1500. The other radiating elements 1400 form the mMIMO array, which preferably includes the other radiating elements 1400 arranged in a plurality of columns. The radiating elements 100 may be arranged in gaps or in increased radiating element spacings or in vacant positions created by left-out radiating elements 100 in these columns, respectively. The radiating elements 100 are thus preferably interleaved with the plurality of other radiating elements 1400. Thereby, different types and/or sizes of dual-polarized radiating elements 100 can be used, for instance, to operate in different kinds of frequency bands in overlap with the mMIMO array.
(64) In summary, the detailed description and the figures show, that and how the radiating element 100 is made low profile, but is at the same time provided with broadband characteristics. Furthermore, that and how the radiating element 100 has a shape that minimizes interference with other radiating elements 1400 arranged side-by-side in a multiband antenna 1500, and minimizes the width of the antenna 1500.
(65) The present invention has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed invention, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.
