Dual polarization antenna device
The dual polarization antenna device with symmetric coplanar striplines and parallel plate transmission lines addresses unbalanced feeding issues in square dipoles, ensuring stable patterns and broader bandwidth by reducing manufacturing complexity and interference.
Patent Information
- Application Number
- PCT/EP2024/070066
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-16
- Publication Date
- 2026-01-22
AI Technical Summary
Existing square dipole antennas face challenges with unbalanced feeding, leading to self-resonating effects, increased manufacturing complexity, and limited operational bandwidth due to bulky ground planes and the need for additional power splitters, which interfere with satellite communications.
A dual polarization antenna device with coplanar striplines and parallel plate transmission lines arranged symmetrically to provide a balanced feed for square dipoles, reducing the footprint and manufacturing complexity while maintaining high symmetry and stability.
The solution achieves stable element patterns with narrow vertical beams, minimizing interference with satellites and enabling broader bandwidth operation by avoiding self-resonance effects.
Smart Images
Figure EP2024070066_22012026_PF_FP_ABST
Abstract
Description
[0001] Dual polarization antenna device
[0002] TECHNICAL FIELD
[0003] The disclosure relates to the field of wireless communications and antenna design for high-bandwidth services and wide-area coverage, for example for a communication network. The disclosure relates to a dual polarization antenna device and particularly, to a balanced feed square dipole.
[0004] BACKGROUND
[0005] The recent standardization of a communication network will enable operators to provide ubiquitous high- bandwidth services and wide-area coverage in the near feature, thereby accelerating the digital transformation process of various countries. The communication network spectrum is defined in the band 5925 - 7125 MHz and as such is a compromise between good coverage of sub-6 GHz communications and high bandwidth of mmWaves, however it can cause interference with the uplink of satellite links. Therefore, there is the need to use antenna elements with narrow vertical beam to limit the power radiated towards satellites. A good candidate to fulfill such requirements is the class of antennas of square dipoles.
[0006] SUMMARY
[0007] This disclosure provides a solution for a high symmetry feed suitable for square dipole antennas that allows to achieve stable element patterns that can be used at a communication network frequencies.
[0008] The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.
[0009] Embodiments of the disclosure present a dual polarization antenna device with two coplanar striplines (CPSs) arranged in a symmetric fashion with respect to the antenna symmetry axis feed of the dual-polarization antenna. Each CPS is interconnected to a parallel plate transmission line (PPTL) realizing the required power splitter operation for the square dipole featuring a small footprint. Such arrangement provides a balanced feed for the dualpolarization radiator enabling higher frequencies operation and broader bandwidth by avoiding self-resonance effects known in this class of antennas.
[0010] In order to describe the disclosure in detail, the following terms and notations will be used.
[0011] RF Radio Frequency
[0012] LTE Long Term Evolution
[0013] 5 G Fifth generation technology standard for broadband cellular networks mmWave Millimeter wave
[0014] CPS Coplanar stripline
[0015] PPTL Parallel plate transmission line
[0016] ML Microstrip line
[0017] PCB Printed circuit board In this disclosure, microstrip lines, parallel plate transmission lines and coplanar striplines are described.
[0018] A microstrip line is an electrical transmission line that can be fabricated with any technology where a conductor is separated from a ground plane by a dielectric layer known as "substrate". Microstrip lines are used to convey microwave-frequency signals. A microstrip line is an unbalanced transmission line which is characterized by its asymmetric E-field.
[0019] A parallel plate transmission line is an electrical transmission line consisting of two parallel conducting plates separated by a dielectric slab of a uniform thickness. At microwave frequencies parallel plate transmission lines can be fabricated on a dielectric using printed circuit technology. A parallel plate transmission line is a balanced transmission line which is characterized by its symmetric E-field.
[0020] A coplanar stripline (CPS) is an electrical transmission line consisting of a dielectric substrate with two parallel strip conductors separated by a narrow gap. Both conductors are on the same side of the substrate, and hence are coplanar. A coplanar stripline is a balanced transmission line which is characterized by its symmetric E-field.
[0021] In this disclosure, square dipole antennas and dual polarization antennas are described.
[0022] A dual polarization antenna is an antenna that is capable of receiving and transmitting radiofrequency signals with two distinct forms of polarization (usually horizontal and vertical polarization or +45° / -45° slant polarization), simultaneously.
[0023] Square dipole antennas are good element candidates to provide narrower beams compared to cross dipoles due to the fact that each polarization is fed at two distinct locations resulting in an array factor effect. Typically, those elements are used at frequencies lower than 6 GHz and are fed with MLs at their antenna feeding locations. MLs requires a somewhat large ground plane and a signal line that can become electrically too bulky if the substrate is not proportionally reduced with the higher operational frequency.
[0024] This means that more accurate manufacturing processes are required to avoid unbalanced feeding and related distortion of antenna patterns. Moreover, an unbalanced feed of square dipole give rise to unwanted self-resonating effects, (spikes in the S-parameters and radiation patterns) limiting the operational bandwidth of such antennas. Square dipoles require a power splitter per each polarization which is typically on the vertical feed stalk or at the base of the antenna itself requiring additional footprint.
[0025] Therefore, to relax manufacturing accuracy, reduce costs, and have a power splitter with small footprint while maintaining high balanced feed, a new square dipole antenna with a simple and effective feed is presented in this disclosure. The new square dipole antenna is also referred to as dual polarization antenna device hereinafter. This new square dipole antenna allows to achieve improved pattern stability being less dependent on substrate thickness therefore enabling an easier implementation of square dipole antennas. Embodiments of the disclosure present a dual-polarized square dipole fed by CPSs arranged in a symmetric fashion with respect to the radiator. In the antenna design, CPSs are used to feed the radiator. Each pair of CPS intersects with a PPTL which is the main transmission line on the feed stalk of the antenna (the part between the base and the top of the antenna). In the antenna design, a PPTL is used on the feed stalk. The intersection between CPS and PPTL realizes a power splitter with small footprint.
[0026] According to a first aspect, the disclosure relates to a dual polarization antenna device comprising: a planar radiator) arranged at an antenna radiator plane spanned by two antenna symmetry axes, each antenna symmetry axis being associated with a polarization of a polarization characteristic of the antenna device, the planar radiator comprising four metallic parts, each metallic part arranged in a respective quadrant of the antenna radiator plane; two coplanar striplines, each coplanar stripline arranged along a respective one of the two antenna symmetry axes, wherein each coplanar stripline comprises two stripline sections coplanar arranged with respect to each other, each stripline comprising two terminals and a feeding point between the two terminals, wherein each terminal of a coplanar stripline is electrically connected to respective two of the four metallic parts of the radiator for feeding the radiator; and two antenna feeding lines being electrically connected to feed the radiator via the two coplanar striplines at the feeding points of the respective coplanar striplines.
[0027] Such a dual polarization antenna device provides a high symmetiy feed suitable for square dipole antennas that allows to achieve stable element patterns. The dual polarization antenna device can be designed with narrow vertical beam to limit the power radiated towards satellites.
[0028] The antenna device allows to relax manufacturing accuracy, reduce costs, and have a small footprint power splitter while maintaining high balanced feed. Such antenna device allows to achieve improved pattern stability being less dependent on substrate thickness therefore enabling an easier implementation of square dipole antennas.
[0029] In an exemplary implementation of the antenna device, the four metallic parts of the planar radiator are symmetrically arranged with respect to the two antenna symmetry axes. This feature together with the abovedescribed implementation of the coplanar striplines, where each terminal of a coplanar stripline is electrically connected to respective two of the four metallic parts of the radiator for feeding the radiator allows to feed the antenna in a highly balanced way and allows differential feeding.
[0030] In an exemplary implementation of the antenna device, the four metallic parts of the planar radiator have a trapezoidal shape and are arranged in the antenna radiator plane with a 90° rotational symmetry. Such antenna device can achieve high self-interference cancellation due to the symmetrical design.
[0031] In an exemplary implementation of the antenna device, the two antenna feeding lines extend to the antenna radiator plane in a central section of the antenna radiator plane between the two pair of terminals. This allows to implement the antenna device in a compact design by three PCBs, one for the antenna radiator plane, and two others for the two antenna feeding lines. Such antenna device can be easily manufactured. In an exemplary implementation of the antenna device, the two coplanar striplines are arranged at a central section of the antenna radiator plane. This allows to easily implement power splitting between the coplanar striplines and the antenna feeding lines without the need to design an ad hoc power splitter device.
[0032] In an exemplary implementation of the antenna device, each of the two antenna feeding lines comprises a parallel plate transmission line and a number of vias for interconnection to the two coplanar striplines. Both the CPS and the parallel plate transmission line feature a highly symmetric E-field that is used to feed the planar radiator, therefore realizing a highly balanced antenna feed.
[0033] In an exemplary implementation of the antenna device, an interconnection of the two antenna feeding lines to the two coplanar striplines implements a power splitting operation. Thus, the power splitting operation can be achieved by the antenna device due to its design without the need to design an ad hoc power splitter device.
[0034] In an exemplary implementation of the antenna device, a first one of the two coplanar striplines is formed along a straight line in the antenna radiator plane; and a second one of the two coplanar striplines forms a crossover below or above the first coplanar stripline, in order to avoid short circuiting between the two coplanar striplines. The straight line and crossover avoids any short circuiting between the two coplanar striplines.
[0035] In an exemplary implementation of the antenna device, the dual polarization antenna device comprises: a multilayer printed circuit board comprising a first metal layer and a second metal layer; wherein the four metallic parts of the planar radiator and the two coplanar striplines are formed by the first metal layer of the multi-layer printed circuit board. This allows to efficiently produce the antenna device by using PCB technology.
[0036] In an exemplary implementation of the antenna device, a first one of the two coplanar striplines is formed by the first metal layer along a straight line; and a second one of the two coplanar striplines is formed by the first metal layer and the second metal layer of the multi-layer printed circuit board and vias between the first metal layer and the second metal layer, the vias forming a crossover between the two coplanar striplines without short circuiting the two coplanar striplines. Accordingly, a crossover between the two coplanar striplines is formed to avoid any short circuiting.
[0037] In an exemplary implementation of the antenna device, the dual polarization antenna device comprises: a second multi-layer printed circuit board comprising a first metal layer and a second metal layer; and a third multi-layer printed circuit board comprising a first metal layer and a second metal layer; wherein a first antenna feeding line of the two antenna feeding lines is formed by the first metal layer and the second metal layer of the second multilayer printed circuit board; and wherein a second antenna feeding line of the two antenna feeding lines is formed by the first metal layer and the second metal layer of the third multi-layer printed circuit board. The antenna feeding lines are formed from the metal layers of the printed circuit boards by using PCB technology.
[0038] In an exemplary implementation of the antenna device, each of the second multi-layer printed circuit board and the third multi-layer printed circuit board are arranged orthogonally with respect to each other and with respect to the first multi-layer printed circuit board; wherein each of the second multi-layer printed circuit board and the third multi-layer printed circuit board comprises protrusions which are inserted into corresponding cutouts on the first multi-layer printed circuit board. The second multi-layer printed circuit board and the third multi-layer printed circuit board may also have cutouts to enable their mechanical intersection. By such protrusions and cutouts, the antenna device can be easily formed by inserting the PCBs with respect to each other.
[0039] In an exemplary implementation of the antenna device, the dual polarization antenna device comprises: one or more metal rings formed by at least one of the first metal layer and the second metal layer of the multi-layer printed circuit board in the near field region of the radiator, wherein the one or more metal rings are configured to optimize the input impedance of the dual polarization antenna device. By such metal rings, the input impedance of the antenna device can be adjusted and optimized.
[0040] In an exemplary implementation of the antenna device, the dual polarization antenna device comprises: two pairs of metal rods; wherein a first antenna feeding line of the two antenna feeding lines is formed by a first pair of the two pairs of metal rods; and wherein a second antenna feeding line of the two antenna feeding lines is formed by a second pair of the two pairs of metal rods. The transmission lines from the antenna base to the CPS can be made of metallic rods, therefore minimizing dielectric losses and requiring only one substrate for the radiator and CPSs to be used for the entire antenna. This allows further simplification in production.
[0041] In an exemplary implementation of the antenna device, the dual polarization antenna device is forming a dual polarization square dipole antenna.
[0042] The dual polarization square dipole antenna allows to create narrow vertical beam to limit the power radiated towards satellites.
[0043] BRIEF DESCRIPTION OF THE DRAWINGS
[0044] Further embodiments of the disclosure will be described with respect to the following figures, in which:
[0045] Figure 1 shows a 3-dimensional representation of a dual polarization antenna device 100;
[0046] Figure 2 shows the dual polarization antenna device 100 of Figure 1 from the bottom side;
[0047] Figure 3 shows another perspective of the dual polarization antenna device 100 of Figure 1;
[0048] Figure 4 shows another perspective of the dual polarization antenna device 100 of Figure 1;
[0049] Figure 5 shows a 3-dimensional representation of a dual polarization antenna device 200;
[0050] Figure 6 shows the dual polarization antenna device 200 of Figure 4 from the bottom side;
[0051] Figure 7 shows a 3-dimensional representation of the dual polarization antenna device 100 shown in Figure 1 where only the metallic parts 700 of the coplanar striplines and antenna feeding lines are shown; and
[0052] Figure 8 shows another perspective of the metallic parts 700 of the coplanar striplines and antenna feeding lines shown in Figure 7. DETAILED DESCRIPTION OF EMBODIMENTS
[0053] In the following detailed description, reference is made to the accompanying drawings, which form a part thereof, and in which is shown by way of illustration specific aspects in which the disclosure may be practiced. It is understood that other aspects may be utilized and structural or logical changes may be made without departing from the scope of the disclosure. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the disclosure is defined by the appended claims.
[0054] It is understood that comments made in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if a specific method step is described, a corresponding device may include a unit to perform the described method step, even if such unit is not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary aspects described herein may be combined with each other, unless specifically noted otherwise.
[0055] Figure 1 shows a 3-dimensional representation of a dual polarization antenna device 100.
[0056] The dual polarization antenna device 100 comprises a planar radiator 110 arranged at an antenna radiator plane 120 spanned by two antenna symmetiy axes 120a, 120b. Each antenna symmetry axis 120a, 120b is associated with a polarization of a polarization characteristic of the antenna device 100. The planar radiator 110 comprises four metallic parts 110a, 110b, 110c, HOd. Each metallic part 110a, 110b, 110c, HOd is arranged in a respective quadrant of the antenna radiator plane 120 as can be seen from Figure 1.
[0057] The dual polarization antenna device 100 comprises two coplanar striplines 130, 140. Each coplanar stripline is arranged along a respective one of the two antenna symmetry axes 120a, 120b. Each coplanar stripline comprises two stripline sections 130a, 130b, 140a, 140b coplanar arranged with respect to each other. Each stripline comprises two terminals 151, 152, 154, 155 as depicted in Figure 1 and a feeding point 153, 156 between the two terminals 151, 152, 154, 155. Each terminal 151, 152, 154, 155 of a coplanar stripline 130, 140 is electrically connected to respective two of the four metallic parts 110a, 110b, 110c, 1 lOd of the radiator 110 for feeding the radiator 110. As can be seen from the exemplary configuration of Figure 1, terminal 151 is electrically connected to metallic parts 110a and 1 lOd; terminal 152 is electrically connected to metallic parts 110b and 110c; terminal 154 is electrically connected to metallic parts 110c and HOd; terminal 155 is electrically connected to metallic parts 110a and 110b.
[0058] The dual polarization antenna device 100 comprises two antenna feeding lines 160, 170 which are electrically connected to feed the radiator 110 via the two coplanar striplines 130, 140 at the feeding points 156, 153 of the respective coplanar striplines 130, 140.
[0059] Both of the lines 130, 140 and 160, 170 implement antenna feeding lines, where the feeding lines 130, 140 may be referred to as “primary antenna feeding lines” and the feeding lines 160, 170 may be referred to as “secondary antenna feeding lines”. In an exemplary implementation, the feeding lines 160, 170 or secondary feeding lines 160, 170 may be implemented as parallel plate transmission lines (PPTLs).
[0060] The four metallic parts 110a, 110b, 110c, HOd of the planar radiator 110 may be symmetrically arranged with respect to the two antenna symmetry axes 120a, 120b as shown in Figure 1.
[0061] The four metallic parts 110a, 110b, 110c, 1 lOd of the planar radiator 110 may have a trapezoidal shape and may be arranged in the antenna radiator plane 120 with a 90° rotational symmetry, as shown in the exemplary design of Figure 1.
[0062] The two antenna feeding lines 160, 170 may extend to the antenna radiator plane 120 in a central section of the antenna radiator plane 120 between the two pair of terminals 151, 152, 154, 155 as shown in Figure 1.
[0063] The two coplanar striplines 130, 140 may be arranged at a central section of the antenna radiator plane 120 as can be seen in Figure 1.
[0064] Each of the two antenna feeding lines 160, 170 may comprise a parallel plate transmission line (PPTL, partially shown in Figure 1) and a number of vias 210 for interconnection to the two coplanar striplines 130, 140.
[0065] An interconnection of the two antenna feeding lines 160, 170 to the two coplanar striplines 130, 140 may implement a power splitting operation.
[0066] The above-mentioned interconnection of antenna feeding hnes 160, 170 and coplanar striplines 130, 140 may realize a power splitting operation at each feeding point 153, 156. For sake of clarity, Figures 7 and 8 highlight the primary and secondary feeding lines of the dual polarization antenna device 100.
[0067] A first one 140 of the two coplanar striplines 130, 140 may be formed along a straight line in the antenna radiator plane 120. A second one 130 of the two coplanar striplines 130, 140 may form a crossover below or above the first coplanar stripline 140 as shown in Figure 1, in order to avoid short circuiting between the two coplanar striplines 130, 140.
[0068] The dual polarization antenna device 100 may comprise: a multi-layer printed circuit board 180 comprising a first metal layer 181 and a second metal layer 182 as shown in Figure 1. The four metallic parts 110a, 110b, 110c, HOd of the planar radiator 110 and the two coplanar striplines 130, 140 may be formed by the first metal layer 181 of the multi-layer printed circuit board 180.
[0069] A first one 140 of the two coplanar striplines 130, 140 may be formed by the first metal layer 181 along a straight line. A second one 130 of the two coplanar striplines 130, 140 may be formed by the first metal layer 181 and the second metal layer 182 of the multi-layer printed circuit board 180 and vias 210 (as shown in Figure 2) between the first metal layer 181 and the second metal layer 182. The vias 210 are forming a crossover between the two coplanar striplines 130, 140 without short circuiting the two coplanar striplines 130, 140.
[0070] The dual polarization antenna device 100 may comprise: a second multi-layer printed circuit board 190 comprising a first metal layer 191 and a second metal layer 192; and a third multi-layer printed circuit board 193 comprising a first metal layer 194 and a second metal layer 195 as shown in Figure 1.
[0071] A first antenna feeding line 160 of the two antenna feeding lines 160, 170 may be formed by the first metal layer 191 and the second metal layer 192 of the second multi-layer printed circuit board 190. A second antenna feeding line 170 of the two antenna feeding lines 160, 170 may be formed by the first metal layer 194 and the second metal layer 195 of the third multi-layer printed circuit board 193.
[0072] Each of the second multi-layer printed circuit board 190 and the third multi-layer printed circuit board 193 are arranged orthogonally with respect to each other and with respect to the first multi-layer printed circuit board 180 as shown in Figure 1.
[0073] Each of the second multi-layer printed circuit board 190 and the third multi-layer printed circuit board 193 may comprise protrusions 250 as shown in Figure 1, which are inserted into corresponding cutouts 251 on the first multi-layer printed circuit board 180. The second 190 and third 193 multi-layer printed circuit board have also cutouts to enable their mechanical intersection.
[0074] The dual polarization antenna device 100 may comprise: one or more metal rings 230 as shown in Figure 2 which may be formed by at least one of the first metal layer 181 and the second metal layer 182 of the multi-layer printed circuit board 180 in the near field region of the radiator 110. The one or more metal rings 230 may be configured to optimize the input impedance of the dual polarization antenna device 100.
[0075] The dual polarization antenna device 100 may form a dual polarization square dipole antenna.
[0076] In the following, further embodiments of the dual polarization antenna device 100 are described.
[0077] Figure 1 shows an optimal implementation of the solution described above, e.g., a square dipole antenna with high symmetry feed that allows to achieve stable element patterns.
[0078] Gray shades represent metallic parts while white sections represent the substrate on which the metal is located. The substrate can be any dielectric material like PCB or even simply air. In Figure 1 the antenna 100 can be implemented with PCB technology but the substrate can be of any other type.
[0079] There are three PCB parts 180, 190, 193 in the implementation, although one single multidimensional monolithic dielectric piece can be used. This depends on manufacturing technology. On the upper PCB 180, there are four metallic parts 110a, 110b, 110c, HOd (trapezoidal shape) composing the radiator which features 90-degree rotational symmetry. The radiator shape can be arbitrary and the symmetry feature is not a requirement but is the preferable choice for balanced performance between the two polarizations of the antenna.
[0080] The radiator 110 is connected to CPSs 130, 140 which are the primary feeding lines for both polarizations. The CPSs 130, 140 are located in the central region of the radiator 110 and their main feature is the high degree of symmetry with respect to the radiator 110 The radiator 110 and the CPS 130, 140 are on the same substrate, that is the upper PCB 180.
[0081] One CPS 140 is located on the top side of the upper substrate 180 while the other one 130 is present on both sides to achieve a suitable line crossover, that is without intersection between the CPSs 130, 140. The crossover of one CPS 130 is realized by using vias (metallic rods connecting both sides of the substrate). In general, the CPS can be on both sides depending on the configuration, therefore their relative position to each other and the radiator is not relevant for the idea.
[0082] Figure 1 shows also two additional substrates 190, 193 each of which has a transmission line, in particular a PPTL, which is the secondary type feeding of the antenna 100. Those two substrates 190, 193 are orthogonal to the upper substrate 180 for mechanical stability, but this is not a mandatory requirement. In Figure 1 one can see only one side of each PPTL, the other side is not visible as it is on the opposite side of each substrate.
[0083] Figure 2 shows the dual polarization antenna device 100 of Figure 1 from the bottom side.
[0084] The CPSs 130, 140 (only partially shown in Figure 2, see top side shown in Figure 1) are interconnected to PPTLs 160, 170 whose transition realize a power splitter with small footprint. The transition requires electrical continuity therefore soldering material should be used (not shown in Figures), or continuous metallization must be ensured. This depends on the technology. The CPS 130, 140 have a number of vias 210 to allow interconnection with PPTLs 160, 170.
[0085] At the bottom of the upper substrate 180 a ring 230 is present, which helps in obtaining the correct input matching of the antenna 100. The presence of the ring 230 is optional.
[0086] The PPTLs 160, 170 at one side are connected to the CPSs 130, 140 while on the other end shall be connected to other feeding hnes (corporate feeding network) which are independent parts of this idea (not shown). The PPTLs 160, 170 have a larger width at the base of the antenna 100 as can be seen from Figure 2 for ensuring better soldering area to the rest of the antenna array system. This different width at one end of the PPTLs is just optional.
[0087] The shape of the substrates at the bottom of the antenna 100 is optimized to be fitted into bigger array system but the shape does not play any key role as it can be arbitrary. Figure 3 shows another perspective of the dual polarization antenna device 100 of Figure 1 and specifically the other metallic side of the second PPTL 170. This is just to point out that the PPTL 170 is made out of two equal metallic parts, each on both sides of the substrate.
[0088] Figure 3 also shows some of the vias 210 for interconnection of the PPTL 170 to the respective coplanar stripline 140.
[0089] In this perspective, it can be seen that the second multi-layer printed circuit board 190 and the third multi-layer printed circuit board 193 are arranged orthogonally with respect to each other and with respect to the first multilayer printed circuit board 180.
[0090] Both, the second multi-layer printed circuit board 190 and the third multi-layer printed circuit board 193 comprise protrusions 250 which are inserted into corresponding cutouts 2 1 on the first multi-layer printed circuit board 180.
[0091] Figure 4 shows another perspective of the dual polarization antenna device 100 of Figure 1 and specifically the metallic side of the first PPTL 160. This is again to point out that the PPTL 160 is also made out of two equal metallic parts, each on both sides of the substrate 190.
[0092] As can be seen from Figure 4, each coplanar stripline comprises two terminals 151, 152, 154, 155 as depicted in Figure 1 and a feeding point 153, 156 between the two terminals 151, 152, 154, 155. The first coplanar stripline 140 (in vertical direction in Figure 4) comprises the two terminals 151, 152 and the first coplanar stripline 140 is fed via the feeding point 153 between these two terminals 151, 152.
[0093] The second coplanar stripline 130 (in horizontal direction in Figure 4) comprises the two terminals 154, 155 and the first coplanar stripline 130 is fed via the feeding point 156 between these two terminals 154, 155.
[0094] The CPS and PPTL feeding described above with respect to Figures 1 to 4 is an optimal solution to feed a square dipole antenna in a highly balanced way. This is because the feeding is highly differential as it should be in an ideal type of excitation. Indeed, all the signal lines and the associated ground metallic parts required for a differential feeding are completely symmetric and equal to each other in this implementation, which is a main requirement for any transmission line to achieve differential type of feeding. As a matter of fact, signal and ground lines cannot be distinguished between each other.
[0095] This configuration also allows to minimize the footprint of the power splitter required to feed this class of antennas.
[0096] The benefit of the high balanced feeding is enabling this class of antennas (square dipoles) to achieve stable radiation patterns (close to ideal patterns) at higher frequency and broader bandwidth due to self-resonances avoidance. The latter (e.g., self-resonances) is a known effect in such antennas occurring when the feeding is not very well balanced. Figure 5 shows a 3-dimensional representation of a dual polarization antenna device 200. A variation of the embodiments of Figures 1 to 4 is presented in Figures 5 and 6.
[0097] In contrast to the embodiments shown in Figures 1 to 4, the dual polarization antenna device 200 comprises: two pairs of metal rods 240 as shown in Figures 5 and 6. A first antenna feeding line 160 of the two antenna feeding lines 160, 170 may be formed by a first pair of the two pairs of metal rods 240. A second antenna feeding line 170 of the two antenna feeding lines 160, 170 may be formed by a second pair of the two pairs of metal rods 240.
[0098] The two bottom substrates with their PPTLs are substituted by metallic rods 240 that work as transmission lines. Each polarization has two rods (signal and ground) which should be fed differentially at the base of the antenna. The metallics rods 240 provide the same symmetry features as PPTLs as described above with respect to Figures 1 to 4.
[0099] The radiator and CPS with their substrate are supported entirely by the rods 240. The four rods 240 pass through the upper dielectric to realize mechanical stability. Any other type of dielectric supports can also be used to realize mechanical stability. The cross section of the rods 240 can be circular but it can be arbitrarily, e.g., square shape or others.
[0100] Figure 6 shows the dual polarization antenna device 200 of Figure 5 from the bottom side. The transmission lines from the antenna base to the CPS are made out of metallic rods therefore minimizing dielectric losses and requiring only one substrate for the radiator and CPSs to be used for the entire antenna 200.
[0101] Figure 7 shows a 3-dimensional representation of the dual polarization antenna device 100 shown in Figure 1 where only the metallic parts 700 of the coplanar striplines and antenna feeding lines are shown.
[0102] Figure 7 clearly shows the different design of the two coplanar striplines 130, 140. The first one 140 is formed along a straight line in the antenna radiatorplane and the one 130 of the two coplanar striplines 130, 140 is forming a crossover below the first coplanar stripline 140, in order to avoid short circuiting between the two coplanar striplines 130, 140.
[0103] The vias 210 made of metal are shown which interconnect the coplanar striplines 130, 140 to the two antenna feeding lines 160, 170.
[0104] Figure 7 also shows a feeding point 156 for electrical connection between the coplanar stripline 130 and the antenna feeding line 160.
[0105] Figure 8 shows another perspective of the metallic parts 700 of the coplanar striplines and antenna feeding lines shown in Figure 7. Figure 8 shows the bottom side of the metallic parts 700 shown in Figure 7. Figure 8 also shows a feeding point 153 for electrical connection between the coplanar stripline 140 and the antenna feeding line 170.
[0106] Figures 7 and 8 show the first and second coplanar striplines 130, 140 and the two antenna feeding lines 160, 170 along with vias 210.
[0107] The solution presented here can be used to realize the unit antenna element of an arbitrary big array. The disclosed solution is suitable but not limited to antenna arrays of a communication network in the future.
[0108] While a particular feature or aspect of the disclosure may have been disclosed with respect to only one of several implementations, such feature or aspect may be combined with one or more other features or aspects of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms "include", "have", "with", or other variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprise". Also, the terms "exemplary", "for example" and "e g." are merely meant as an example, rather than the best or optimal. The terms “coupled” and “connected”, along with derivatives may have been used. It should be understood that these terms may have been used to indicate that two elements cooperate or interact with each other regardless whether they are in direct physical or electrical contact, or they are not in direct contact with each other.
[0109] Although specific aspects have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations may be substituted for the specific aspects shown and described without departing from the scope of the disclosure. This application is intended to cover any adaptations or variations of the specific aspects discussed herein.
[0110] Although the elements in the following claims are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.
[0111] Many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the above teachings. Of course, those skilled in the art readily recognize that there are numerous applications of the disclosure beyond those described herein. While the disclosure has been described with reference to one or more particular embodiments, those skilled in the art recognize that many changes may be made thereto without departing from the scope of the disclosure. It is therefore to be understood that within the scope of the appended claims and their equivalents, the disclosure may be practiced otherwise than as specifically described herein.
Claims
CLAIMS:
1. A dual polarization antenna device (100) comprising: a planar radiator (110) arranged at an antenna radiator plane (120) spanned by two antenna symmetry axes (120a, 120b), each antenna symmetry axis (120a, 120b) being associated with a polarization of a polarization characteristic of the antenna device (100), the planar radiator (110) comprising four metallic parts (110a, 110b, 110c, 1 lOd), each metallic part (110a, 110b, 110c, 1 lOd) arranged in a respective quadrant of the antenna radiator plane (120); two coplanar striplines (130, 140), each coplanar stripline arranged along a respective one of the two antenna symmetry axes (120a, 120b), wherein each coplanar stripline comprises two stripline sections (130a, 130b, 140a, 140b) coplanar arranged with respect to each other, each stripline comprising two terminals and a feeding point (153, 156) between the two terminals, wherein each terminal of a coplanar stripline (130, 140) is electrically connected to respective two of the four metallic parts (110a, 110b, 110c, 1 lOd) of the radiator (110) for feeding the radiator (110); and two antenna feeding lines (160, 170) being electrically connected to feed the radiator (110) via the two coplanar striplines (130, 140) at the feeding points (156, 153) of the respective coplanar striplines (130, 140).
2. The dual polarization antenna device (100) of claim 1, wherein the four metallic parts (110a, 110b, 110c, 1 lOd) of the planar radiator (110) are symmetrically arranged with respect to the two antenna symmetry axes (120a, 120b).
3. The dual polarization antenna device (100) of claim 1 or 2, wherein the four metallic parts (110a, 110b, 110c, 1 lOd) of the planar radiator (110) have a trapezoidal shape and are arranged in the antenna radiator plane (120) with a 90° rotational symmetry.
4. The dual polarization antenna device (100) of any of the preceding claims, wherein the two antenna feeding lines (160, 170) extend to the antenna radiator plane (120) in a central section of the antenna radiator plane (120) between the two pair of terminals.
5. The dual polarization antenna device (100) of any of the preceding claims, wherein the two coplanar striplines (130, 140) are arranged at a central section of the antenna radiator plane (120).
6. The dual polarization antenna device (100) of any of the preceding claims, wherein each of the two antenna feeding lines (160, 170) comprises a parallel plate transmission line and a number of vias (210) for interconnection to the two coplanar striplines (130, 140).
7. The dual polarization antenna device (100) of any of the preceding claims, wherein an interconnection of the two antenna feeding lines (160, 170) to the two coplanar striplines (130, 140) implements a power splitting operation.
8. The dual polarization antenna device (100) of any of the preceding claims, wherein a first one (140) of the two coplanar striplines (130, 140) is formed along a straight line in the antenna radiator plane (120); and wherein a second one (130) of the two coplanar striplines (130, 140) forms a crossover below or above the first coplanar stripline (140), in order to avoid short circuiting between the two coplanar striplines (130, 140).
9. The dual polarization antenna device (100) of any of the preceding claims, comprising: a multi-layer printed circuit board (180) comprising a first metal layer (181) and a second metal layer (182); wherein the four metallic parts (110a, 110b, 110c, 1 lOd) of the planar radiator (110) and the two coplanar striplines (130, 140) are formed by the first metal layer (181) of the multi-layer printed circuit board(180).
10. The dual polarization antenna device (100) of claim 9, wherein a first one (140) of the two coplanar striplines (130, 140) is formed by the first metal layer(181) along a straight line; and wherein a second one (130) of the two coplanar striplines (130, 140) is formed by the first metal layer (181) and the second metal layer (182) of the multi-layer printed circuit board (180) and vias (210) between the first metal layer (181) and the second metal layer (182), the vias forming a crossover between the two coplanar striplines (130, 140) without short circuiting the two coplanar striplines (130, 140).
11. The dual polarization antenna device (100) of claim 9 or 10, comprising: a second multi-layer printed circuit board (190) comprising a first metal layer (191) and a second metal layer (192); a third multi-layer printed circuit board (193) comprising a first metal layer (194) and a second metal layer (195); wherein a first antenna feeding line (160) of the two antenna feeding lines (160, 170) is formed by the first metal layer (191) and the second metal layer (192) of the second multi-layer printed circuit board (190); and wherein a second antenna feeding line (170) of the two antenna feeding lines (160, 170) is formed by the first metal layer (194) and the second metal layer (195) of the third multi-layer printed circuit board (193).
12. The dual polarization antenna device (100) of claim 11, wherein each of the second multi-layer printed circuit board (190) and the third multi-layer printed circuit board (193) are arranged orthogonally with respect to each other and with respect to the first multi-layer printed circuit board (180); wherein each of the second multi-layer printed circuit board (190) and the third multi-layer printed circuit board (193) comprises protrusions (250) which are inserted into corresponding cutouts (251) on the first multi-layer printed circuit board (180).
13. The dual polarization antenna device (100) of any of claims 9 to 12, comprising: one or more metal rings (230) formed by at least one of the first metal layer (181) and the second metal layer (182) of the multi-layer printed circuit board (180) in the near field region of the radiator (110), wherein the one or more metal rings (230) are configured to optimize the input impedance of the dual polarization antenna device (100).
14. The dual polarization antenna device (200) of any of claims 1 to 10, comprising: two pairs of metal rods (240); wherein a first antenna feeding line (160) of the two antenna feeding lines (160, 170) is formed by a first pair of the two pairs of metal rods (240); and wherein a second antenna feeding line (170) of the two antenna feeding lines (160, 170) is formed by a second pair of the two pairs of metal rods (240).
15. The dual polarization antenna device (200) of any of the preceding claims, forming a dual polarization square dipole antenna.
Citation Information
Patent Citations
Ultra compact ultra broad band dual polarized base station antenna
US20180261929A1