Antenna devices, arrays of antenna devices

Abstract

The antenna device includes a radiator configured to radiate electromagnetic signals in a direction parallel to a radiation axis of the antenna device, the radiator having a substantially planar shape perpendicular to the radiation axis, and a resonant structure adjacent to the radiator, the resonant structure having a substantially planar shape parallel to the radiator, the radiator configured to radiate electromagnetic signals in a first frequency band, and the resonant structure configured to have a resonant frequency within the first frequency band.

Description

[Technical field]

[0001] The present disclosure relates generally to the field of telecommunications devices, and more specifically to antenna devices and arrays of antenna devices. [Background technology]

[0002] In recent years, the rapid development of various wireless communication systems has resulted in the consideration of innovative antenna technologies including diversity antennas, reconfigurable antennas, etc. Such systems operate in different frequency bands and, as a result, require separate radiating elements for each frequency band. Typically, multiple antennas may be required at each site to provide an antenna dedicated to such systems. Thus, there is a dire need for a compact antenna as a single structure capable of serving all the required frequency bands. Furthermore, with the increasing demand for deeper integration of antennas with radios such as active antenna systems (AAS), new ways of extending the bandwidth of low profile antennas without compromising the antenna's key performance indicators (KPIs) are required.

[0003] Conventionally, an ever-increasing number of antenna arrays are integrated in the same housing. However, such integration of antenna arrays results in very complex antenna systems, strongly (or unfavorably) affecting the antenna form factor, which is fundamental for the commercial development of such antenna systems. However, such integration usually entails a significant cost. As a result, new concepts / architectures, different from conventional technologies, need to be developed to cover standard operating bands in antenna systems, including but not limited to modern base station antenna systems, maintaining the same Radio Frequency (RF) performance, and to easily integrate antenna elements with other components.

[0004] Furthermore, while considering the performance of the antennas (or radiating elements), integrating a larger number of antennas (and, consequently, frequency bands) together in a small space means a high level of coupling (undesired energy transfer) between them, which reduces the signal quality. Coupling between systems (or antennas) can be a significant limitation on the performance and therefore the capabilities offered by the antennas. It is therefore of great importance to suppress or reduce the level of coupling and mitigate its effects as much as possible. As a result, a need has arisen for antennas or systems with improved isolation between antenna arrays. In other words, a need has arisen for a system or method for detuning an antenna in a desired frequency band in order to eliminate unwanted coupling with adjacent antennas, especially for antenna systems with alternative frequency bands.

[0005] Furthermore, conventionally, a duplexer is coupled to the antenna system to separate the transmit (TX) and receive (RX) signal paths. The duplexer allows both TX and RX circuits to share the same antenna, saving space and cost, while separating the TX and RX signals from each other. Usually, the TX and RX signals occupy different frequency bands, in which case the duplexer can incorporate the functions of bandpass filtering and frequency multiplexing into the antenna device. However, as an additional device, the duplexer itself increases the physical footprint of the antenna, taking up extra space and additional cost. Furthermore, such conventional antenna devices consume more resources, i.e., they require more manpower, skill, or effort and time for their placement. Typically, the increased number of components results in more contacts, and more solder joints are required to electrically couple such contacts. Furthermore, for conventional antenna devices operating in multiple frequency bands, failure-free and interference-free communication always remains a challenge.

[0006] In view of the foregoing, therefore, a need exists to overcome the above-mentioned shortcomings associated with conventional antenna devices. Summary of the Invention

[0007] The present disclosure seeks to provide an antenna device and an array of antenna devices. The present disclosure seeks to provide a solution to the existing problems of construction and manufacturing complexity and installation associated with conventional antenna devices. The objective of the present disclosure is to provide a solution that at least partially overcomes the problems encountered in the prior art and to provide an improved antenna device that can be easily implemented and has low construction and manufacturing complexity. Furthermore, the antenna device of the present disclosure seeks to operate in multiple frequency bands, resulting in improved performance without the need for additional devices such as duplexers. Furthermore, the present disclosure seeks to provide a solution to the existing problem of inherent coupling between adjacent antenna devices operating in multiple frequency bands, minimizing the effects of antenna placement.

[0008] The object of the present disclosure is achieved by the solutions provided in the following independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.

[0009] In a first aspect, the present disclosure provides an antenna device, the antenna device including a radiator configured to radiate electromagnetic signals in a direction parallel to a radiation axis of the antenna device, the radiator having a substantially planar shape perpendicular to the radiation axis, and a resonant structure adjacent to the radiator, the resonant structure having a substantially planar shape parallel to the radiator, the radiator configured to radiate electromagnetic signals in a first frequency band, and the resonant structure configured to have a resonant frequency within the first frequency band.

[0010] The antenna device of the present disclosure is a low-profile, lightweight, compact antenna device that integrates more frequency bands and maintains a small form factor. The antenna device is compact in size and has lower complexity (i.e., structural and manufacturing complexity) compared to conventional antenna devices. For example, the antenna device does not use components such as probes or cables to connect feed lines, thereby reducing the overall complexity of the antenna device. Furthermore, the antenna device filters one or more frequency bands (i.e., sub-bands) based on the resonant frequencies associated with the resonant structures without implementing additional filters. Furthermore, the antenna device does not require any additional devices (such as duplexers) to operate within multiple frequency bands, and also eliminates or significantly minimizes coupling between adjacent antenna devices. As a result, the number of additional devices and components is reduced, thereby reducing the number of solder joints required for installation of the antenna device. As a result, the overall structural and manufacturing complexity associated with the antenna device is reduced, which reduces the installation effort in terms of time, cost, and labor. Furthermore, the directivity of the antenna device is improved by having a resonant structure parallel to the radiation direction and radiation axis of the radiator.

[0011] In the implementation, the resonant structure is placed in the reactive near field of the radiator.

[0012] In another implementation, the distance between the radiator and the resonant structure is less than or equal to the central wavelength λ of the first frequency band. central and is determined based on 0.001 to 0.1 λ central is determined to be between

[0013] In another implementation, the resonant structure is formed from one of a metal sheet, a printed circuit board, or a metal foil deposited substrate; and is attached to the radiator by one or more supports or to a substrate laminated to the radiator.

[0014] Implementing the resonant structures in this way makes the antenna device compact and reduces the constructional complexity and installation effort. Furthermore, implementing it as a metal sheet, a printed circuit board, or metallized plastic allows greater flexibility for designing the filters.

[0015] In another implementation, the radiator is a patch antenna and the antenna device further includes a director having a planar structure disposed parallel to and spaced apart from the radiator.

[0016] Compared with traditional antenna devices, patch antennas have a small profile, light weight, and low power consumption, as well as low cost, small size, and easy to manufacture and adapt.

[0017] In another implementation, the antenna device further includes at least one second resonant structure adjacent to the director, the resonant structure having a substantially planar shape parallel to the director; the second resonant structure configured to have a second resonant frequency within the first frequency band.

[0018] The director provides the antenna device with increased impedance bandwidth and high directivity, which is achieved directly or indirectly through the resonant structures acting as parasitic elements.

[0019] In another implementation, the resonant structure is configured to act as a parasitic element of an antenna device.

[0020] The resonant structures acting as parasitic elements significantly affect the input impedance of the antenna device with respect to the size and position of the resonant structures. Furthermore, improved bandwidth and / or improved radiation can be achieved directly or indirectly by the resonant structures (or parasitic elements).

[0021] In another implementation, the shape of the resonant structure is symmetric about a center point of the resonant structure.

[0022] In another implementation, the length of the resonant structure is determined based on the resonant frequency.

[0023] The length of the resonant structure is varied according to the implementation requirements to provide an optimal frequency range for the antenna device to operate in. This variation in length allows two or more multiple devices to operate without coupling, resulting in improved overall performance.

[0024] In another implementation, the resonant frequency is determined based on a second frequency band radiated by another antenna device positioned adjacent to the antenna device.

[0025] Determining the resonant frequency based on the frequency band of adjacent antenna devices allows multiple antenna devices to coexist and operate without coupling or interference during operation, allowing optimal operation for the antenna devices.

[0026] In a second aspect, the present disclosure provides an array of two or more antenna devices, the array comprising two or more antenna devices of the first aspect.

[0027] The use of two or more additional devices in combination with an antenna device allows the antenna device to operate in multiple frequency bands (i.e., two or more frequency bands). This can improve the overall capabilities of the antenna device and allows the antenna device to accommodate one or more antenna devices in its surroundings without degrading the performance of the antenna device. Furthermore, such measures allow multiple antenna devices to operate coexistently without interference or coupling between the two or more antenna devices. Furthermore, integrating multiple antenna devices into an array improves the overall performance and reduces the overall complexity and associated costs of the antenna device.

[0028] The array of antenna devices of the second aspect achieves all the advantages and benefits of the antenna devices of the first aspect.

[0029] In another implementation, an array of antenna devices includes a first antenna device operating in a first frequency band and having a first resonant structure tuned to a first resonant frequency, and further includes a second antenna device operating in a second frequency band and having a second resonant structure tuned to a second resonant frequency, where the first resonant frequency is determined based on the second frequency band and the second resonant frequency is based on the first frequency band.

[0030] Implementing the array in this manner and determining the resonant frequencies based on the frequency bands of adjacent antenna devices allows the antenna devices of the array to coexist and operate without coupling or interference during operation by detuning the frequency bands with high return loss, allowing optimal operation for the antenna devices. Additionally, such implementation allows for duplex operation of the array without the use of additional devices such as duplexers.

[0031] In another implementation, the array of antenna devices includes a first antenna device configured for an uplink and a second antenna device configured for a downlink.

[0032] Implementing an array of antenna devices in this manner allows for bidirectional communication with the antenna devices without the need for implementing duplexers, thereby reducing the physical implementation area and associated manufacturing costs.

[0033] In another implementation, the first frequency band overlaps with the second frequency band.

[0034] Even if there is overlapping of frequency bands, due to the overlapping regions being detuned by the antenna devices, no signal interference or scattering effects are incurred during operation of the antenna devices.

[0035] In another implementation, the first frequency band and the second frequency band each include a plurality of sub-bands, the sub-bands of the first frequency band being interleaved with the sub-bands of the second frequency band.

[0036] It will be appreciated that all implementations described herein can be combined. It should be noted that all devices, elements, circuits, units and means described herein can be implemented with software or hardware elements or any kind of combination thereof. All steps performed by various entities described herein, as well as functions described as being performed by various entities, are intended to mean that the respective entities are adapted or configured to perform the respective steps and functions. Even if in the following description of specific embodiments, a particular function or step performed by an external entity is not reflected in the description of the particular detailed elements of that entity performing that particular step or function, it should be clear to those skilled in the art that these methods and functions can be implemented with respective software or hardware elements or any kind of combination thereof. It will be appreciated that features of the present disclosure can be combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

[0037] Additional aspects, advantages, features, and objectives of the present disclosure will become apparent from the following detailed description of exemplary implementations and drawings, taken in conjunction with the accompanying claims. [Brief description of the drawings]

[0038] The foregoing summary and the following detailed description of exemplary embodiments will be best understood when viewed in conjunction with the accompanying drawings. For the purpose of illustrating the disclosure, exemplary configurations of the disclosure are shown in the drawings. The disclosure is not limited, however, to the particular methods and instrumentalities disclosed herein. In addition, those skilled in the art will appreciate that the drawings are not to scale. Wherever possible, similar elements will be designated with the same numerals. Embodiments of the present disclosure are now described, by way of example only, with reference to the following figures, in which: [Figure 1] FIG. 1 is a perspective view of an antenna device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is an exploded view of the antenna device of FIG. 1 with the surrounding wall removed, according to an embodiment of the present disclosure. [Diagram 3] FIG. 3 is a perspective view of an antenna device other than the antenna device of FIG. 1 according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a block diagram of an array of antenna devices according to an embodiment of the present disclosure. [Diagram 5] FIG. 5 is an example frequency band of an array of antenna devices of FIG. 4 according to an embodiment of the present disclosure. [Figure 6A] FIG. 6A is a graphical representation illustrating coupling between two antenna devices in two different frequency bands, according to an embodiment of the present disclosure. [Figure 6B] FIG. 6B is a graphical representation illustrating the effect of coupling between the two antenna devices of FIG. 6A in two different frequency bands, in accordance with an embodiment of the present disclosure. [Figure 7A] FIG. 7A is a graphical representation illustrating return loss and polarization of an electromagnetic signal radiated by a first antenna device in a first frequency band, according to an embodiment of the present disclosure. [Figure 7B] FIG. 7B is a graphical representation illustrating return loss and polarization of an electromagnetic signal radiated by a second antenna device in a second frequency band in accordance with an embodiment of the present disclosure. [Figure 8]FIG. 8 is an exemplary alternative embodiment of a resonant structure of an antenna device according to various embodiments of the present disclosure. [Figure 9] FIG. 9 is an exemplary alternative embodiment of a resonant structure of an antenna device according to various embodiments of the present disclosure. [Figure 10] FIG. 10 is an exemplary alternative embodiment of a resonant structure of an antenna device according to various embodiments of the present disclosure. [Figure 11] 11 is an exemplary alternative embodiment of a resonant structure of an antenna device according to various embodiments of the present disclosure. In the accompanying drawings, underlined numbers are used to represent the item that overlies or is adjacent to the underlined number. Numbers without underlines relate to the item identified by the line connecting the ununderlined number to the item. When a number is not underlined and has an associated arrow, the ununderlined number is used to identify the overall item to which the arrow points. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] The following detailed description illustrates embodiments of the present disclosure and ways in which they may be implemented. Although several modes of implementing the present disclosure are disclosed, those skilled in the art will recognize that other embodiments are possible for implementing or achieving the present disclosure.

[0040] FIG. 1 is a perspective view of an antenna device according to an embodiment of the present disclosure. Referring to FIG. 1, an antenna device 100 is shown. The antenna device 100 includes a radiator 102 and a resonant structure 104 (better shown in FIG. 2). The radiator 102 includes a substantially planar shape perpendicular to a radiation axis X. Further shown within the antenna device 100 is a first set of support structures 112 including a first support structure 112A, a second support structure 112B, a third support structure 112C, and a fourth support structure 112D.

[0041] The antenna device 100 may be referred to as a radiating element of an antenna, a radiating device, or an antenna element. The antenna device 100 is used for communication. For example, the antenna device 100 may be used in a wireless communication system. In some embodiments, an array of such antenna devices or one or more antenna devices may be used in a communication system. Examples of such wireless communication systems include, but are not limited to, base stations (evolved Node B (eNB), gNB, etc.), repeater devices, customer premises equipment, and other customized telecommunications hardware.

[0042] The radiator 102 is configured to radiate electromagnetic signals along an X direction of the antenna device 100. It will be apparent that an electromagnetic signal is radiated when the antenna device 100 is in operation. The term "electromagnetic signal" includes signal propagation due to simultaneous periodic variations in the strength of electric and magnetic fields, and includes radio waves, microwaves, infrared, light, ultraviolet, X-rays, and gamma rays. The term "radiation axis" refers to an axis having the same direction as the electromagnetic signal radiated from the radiator 102. The radiator 102 has a substantially planar shape perpendicular to the radiation axis X. The term "substantially planar" refers to the shape of the radiator 102, i.e., a flat, uninterrupted shape that may include perforations or openings, depressions, or other interruptions therein. It will further be understood that the shape of the radiator 102 may be curved or bent. As shown in FIG. 1, the radiator 102 has a substantially planar shape and is disposed in a direction perpendicular to the radiation axis X. The radiator 102 is configured to radiate electromagnetic signals in a first frequency band. An electromagnetic signal must occupy a range of frequencies over which it carries most of its energy, called the bandwidth. The term "frequency band" may refer to a communication channel or may be sub-divided into various frequency bands depending on the implementation, such as a first frequency band, a second frequency band, etc. In one example, the first frequency band may be defined by a frequency range, i.e., 1.7 GHz to 2.0 GHz. In another example, the second frequency band may be defined by a frequency range, i.e., 1.8 GHz to 2.2 GHz.

[0043] According to an embodiment, the radiator 102 is a patch antenna. The term "patch antenna" refers to a type of low-profile antenna that may be mounted on a flat surface such as a flat radiating patch. In particular, the flat radiating patch forms the portion of the radiator 102 that is configured to radiate electromagnetic signals along the X-direction. Generally, the radiator 102 is constructed of a flat rectangular sheet or "patch" of metal, mounted on top of a larger metal sheet called the ground plane. In an implementation, the radiator 102 is a metal patch radiator. Advantageously, patch antennas offer a lightweight, low-profile, planar configuration. Furthermore, patch antennas offer ease of manufacture and integration with other devices, such as other antenna devices.

[0044] In an embodiment, the resonant structure 104 is disposed on the radiator 102 of the antenna device 100. The term "resonant structure" refers to an element of the antenna device 100 that is configured to resonate at a desired frequency during operation. The desired frequency is a frequency at which the resonant structure 104 is preferred to filter the electromagnetic signal radiated by the antenna device 100. In this sense, the resonant structure 104 detunes the radiator 102 at the resonant frequency of the resonant structure 104. The resonant structure 104 is disposed adjacent to the radiator 102 at a predetermined distance from the radiator 102. The resonant structure 104 has a substantially planar shape parallel to the radiator 102. The resonant structure 104 has a cross-shaped structure (as shown in FIG. 2) with two elongated arms (also called stubs). Furthermore, the resonant structure 104 has a uniform shape, i.e., the physical dimensions of the resonant structure 104, such as the width and length of the cross-shaped structure of the resonant structure 104, are uniform. It will be apparent that primarily the appropriate length allows the resonant structure 104 to resonate at a desired frequency during operation. Typically, the length L of the stub is made uniform, and thus the size of the resonant structure 104 achieves the desired operating frequency. However, it will be understood by those skilled in the art that the shape and size of the resonant structure 104 may be changed without limiting the scope of the disclosure. Furthermore, the size and shape of the resonant structure 104 may be changed to accommodate a desired resonant frequency. Alternatively, the resonant frequency may be changed by changing the size and shape of the resonant structure 104. For example, the length of the stub may be changed to provide the antenna device 100 with a dual resonance.

[0045] According to an embodiment, the shape of the resonant structure 104 is symmetrical with respect to a center point of the resonant structure 104. In particular, the symmetrical cross-shaped structure of the resonant structure 104 enables the antenna device 100 to exhibit dual polarization characteristics, i.e., to respond simultaneously to radio waves of both horizontal and vertical polarization. Furthermore, it will be apparent that if the antenna device 100 is configured to exhibit single polarization characteristics, i.e., to respond only to one direction of polarization, either horizontal or vertical, the resonant structure 104 does not have to be configured to have an asymmetrical structure.

[0046] As shown in FIG. 1, the resonant structure 104 has a cross-shaped structure. Moreover, the cross-shaped structure is symmetrical about the center point of the resonant structure 104. In other words, the center point of the resonant structure 104 divides the resonant structure 104 into two equal halves or equal mirror images for each half of the resonant structure 104 about the center point. That is, the length L of each elongated arm or stub is the same. Optionally, the length L of the stubs can be changed according to the implementation without limiting the scope of the disclosure.

[0047] The resonant structure 104 is configured to have a resonant frequency within a first frequency band. The resonant structure 104 is configured to operate at a resonant frequency within the first frequency band of the radiator 102. The term “resonant frequency” refers to a frequency at which the resonant structure 104 filters a sub-band within the first frequency band associated with the antenna device 100.

[0048] In an embodiment, the resonant structure 104 is disposed in the reactive near-field of the radiator 102. The term "reactive near-field" refers to a region adjacent to an antenna (such as the antenna device 100). In this region, the electric field (or E-field) and the magnetic field (or H-field) of an electromagnetic signal are 90 degrees out of phase with each other and are therefore reactive. In general, the reactive near-field is a region where strong inductive and capacitive effects from currents and charges present in an antenna device (such as the antenna device 100) operable to generate an electromagnetic component (such as an electromagnetic signal) do not behave as in far-field radiation, i.e., the inductive and capacitive effects decrease in power more quickly with distance from the radiator (such as the radiator 102) than the effects of far-field radiation. As shown in FIG. 1, the resonant structure 104 is disposed at a distance from the radiator 102 and in the reactive near-field of the radiator 102.

[0049] According to an embodiment, the resonant structure 104 is spaced apart from the radiator 102, and the distance D between the radiator 102 and the resonant structure 104 is equal to or smaller than the central wavelength λ of the first frequency band. central The term "center wavelength" refers to the midpoint of a spectral bandwidth (such as a first frequency band) in which the filter (or resonant structure 104) operates. Typically, the distance D between the radiator 102 and the resonant structure 104 is maintained by using support tabs (as shown in FIG. 2). In operation, the distance D in the first frequency band is between 0.001 and 0.1 λ. central For example, the speed of light (c) is determined to be between 3×10 8 m / s and assuming a corresponding central wavelength equal to 1.85 GHz for the first frequency band, the distance D between the radiator 102 and the resonant structure 104 will be in the range of 0.0162 cm to 1.62 cm.

[0050] According to an embodiment, the resonant structure 104 is formed from either a metal sheet, a printed circuit board, or a metal-deposited dielectric material foil. In one example, the resonant structure 104 may be implemented as a single-layer printed circuit board, a multi-layer printed circuit board, a flexible PCB, or a flexi-rigid PCB. Additionally, the resonant structure 104 may be formed using folded metal sheets, such as copper, aluminum, iron, and other metal sheets. Additionally, the resonant structure 104 may be a dielectric material foil with metallization deposits. In an implementation, a dielectric (or very thin plastic) foil with metallization deposits is used. In another implementation, the resonant structure 104 is a laser-cut metal sheet. Substrates using dielectric material foils are formed using metallization, which is achieved by printing conductive traces or paths on one or both sides of the substrate. The substrate can be a thermoplastic part, a metal board, a semiconductor sheet, and the like. Dielectric foil materials include, but are not limited to, bakelite or FR4 glass-epoxy. Furthermore, the printing of the conductive traces may be performed using at least one of aerosol jet, inkjet, or screen printing. Furthermore, the resonant structure 104 is attached to the radiator 102 by one or more supports 118 (also called support tabs) or to a substrate (not shown) laminated to the radiator 102. The one or more supports (also called support tabs) are provided at specific locations throughout the radiator 102 to hold the resonant structure 104 at a distance D from the radiator 102. The "substrate" refers to the mechanical support of the radiator 102. To provide this support, the substrate is primarily made of a dielectric material (such as the dielectric material of a dielectric foil), which may affect the electrical performance of the antenna device 100.

[0051] According to another embodiment, the antenna device 100 further comprises a director 106 having a planar structure arranged parallel to and away from the radiator 102. The "director" 106 refers to an element of the antenna device 100 configured to increase the energy gain and directivity of the radiation, i.e., the electromagnetic signal of the radiator 102. The term "director" refers to an element configured to increase the radiation of a driven element (such as the radiator 102) in its own direction. Advantageously, the director 106 is arranged parallel to the radiator 102 so as to enhance the radiation of the radiator 102. In general, the director 106 is a parasitic element. Alternatively, the director 106 receives its energy from the radiator 102. The director 106 is configured to enhance the radiation, i.e., the radiation of the radiated electromagnetic signal, in terms of energy. Alternatively, the director 106 enhances the directivity of the radiator 102. In general, the size of the director (such as director 106) is smaller than the size of the driven elements (such as radiators 102). As shown in FIG. 1, the size of the director 106 is smaller than the size of the radiators 102. In one example, the size of the director 106 is 5% smaller or shorter than the driven elements, i.e., the radiators 102.

[0052] According to an embodiment, the antenna device 100 further includes at least one second resonant structure (such as resonant structure 108) adjacent to the director 106. The second resonant structure 108 is disposed adjacent to the director 106 and has a similar shape to the resonant structure 104 disposed adjacent to the radiator 102, in which case the second resonant structure 108 is smaller than the first resonant structure 104. The second resonant structure 108 has a substantially planar shape parallel to the director 106. Typically, the second resonant structure 108 is disposed adjacent to and parallel to the director 106. Collectively, the radiator 102, the director 106, and each resonant structure, i.e., the first resonant structure 104 and the second resonant structure 108, are disposed parallel to each other and perpendicular to the radiation axis X of the radiator 102. Furthermore, the second resonant structure 108 is configured to have a second resonant frequency within the first frequency band. The second resonant frequency may be different from the first resonant frequency within the first frequency band. However, to achieve an increased rejection level for a frequency band (such as the first frequency band), the second resonant frequency may be the same as the first resonant frequency. Collectively, the first and second resonant frequencies allow for multiple regions within the first frequency band, in which case the radiator 102 is detuned, i.e., detuned at the resonant frequency.

[0053] According to an embodiment, the resonant structures (e.g., the resonant structure 104, the second resonant structure 108) are configured to function as a filter operating at a resonant frequency (e.g., a first resonant frequency, a second resonant frequency, respectively). In particular, the first resonant structure 104 and the second resonant structure 108 are arranged in such a manner that they function as a filter operating at a resonant frequency (e.g., a first resonant frequency for the resonant structure 104, a second resonant frequency for the second resonant structure 108). Here, the resonant structures 104, 108 are configured to reject or filter out sub-bands of a first frequency band, e.g., from 1.8 GHz-1.9 GHz. Alternatively, the antenna device 100 is detuned in the first frequency band.

[0054] According to an embodiment, the resonant structures 104, 108 are configured to function as parasitic elements of the antenna device 100. The term "parasitic element" refers to an element that depends on a feed from another element (such as the radiator 102). In other words, a parasitic element does not have its own feed and helps indirectly to enhance the radiation (or electromagnetic signal). In particular, the resonant structures 104, 108 (i.e., parasitic elements) are not directly connected to a feed. Alternatively, the resonant structures 104, 108 function as parasitic elements and draw power from adjacent elements (such as the radiator 102). As shown in FIG. 1, the resonant structure 104 is electrically coupled to the radiator 102 and draws energy therefrom, and does not have a direct connection to the feed or feed system of the antenna device 100.

[0055] According to an embodiment, the antenna device 100 includes two sets of support structures 112, 114, where a first set of support structures 112 is disposed between the director 106 and the second resonant structure 108, and a second set of support structures 114 (as shown in FIG. 2) is disposed between the radiator 102 and a base 124. The base 124 may be implemented as a PCB and may include, for example, a reflector implemented as a metal layer in the PCB.

[0056] Each set of support structures, i.e., the first set of support structures 112 and the second set of support structures 114, is electrically non-conductive. Furthermore, the first set of support structures 112 is configured to hold the director 106 at a height H from the radiator 102. As shown in FIG. 1, each support structure of the first set of support structures 112 includes two ends, i.e., a first end and a second end, in which the first end of each support structure of the first set of support structures 112 is attached to the director 106 and the second end of each support structure of the first set of support structures 112 is attached to the surrounding wall 110 (which constitutes the antenna cavity) of the antenna device 100. Typically, each of the two sets of support structures 112, 114 is made of plastic and is electrically non-conductive. Each of the two sets of support structures 112, 114 may be formed from a single piece. The antenna device 100 is covered using an enclosing wall 110, the distance of which from the antenna device 100 is adapted based on the implementation. The term "enclosing wall" refers to a wall that surrounds the antenna device, preferably made of a conductive material such as a metal.

[0057] According to an embodiment, the second resonant structure 108 may include extensions at each end of the cross-shaped structure of the second resonant structure 108 and be mechanically coupled to the first set of support structures 112. At each end of the resonant structure 108, two extensions (forming a V-shaped structure) may be disposed and mechanically coupled to two of the four support structures of the first set of support structures 112. As an example, at the first end of the resonant structure 108, the two extensions at the first end of the resonant structure may be coupled to the first support structure 112A and the second support structure 112B. Similarly, at the second end of the resonant structure 108, the two extensions at the second end of the second resonant structure 108 may be coupled to the second support structure 112B and the third support structure 112C, and so on.

[0058] According to an embodiment, the length L of the resonant structures 104, 108 is determined based on the resonant frequency. In general, the length L of the resonant structures 104, 108 follows an inverse relationship with respect to the resonant frequency. For example, the higher the resonant frequency, the shorter the length L of the resonant structures 104, 108, and vice versa. Alternatively, the resonant structures 104, 108 with higher resonant frequencies are shorter in length for electromagnetic signals, while the resonant structures 104, 108 with lower frequency radio signals are longer. As shown in FIG. 1, the length L of the first resonant structure 104 is greater than the length (not shown) of the resonant structure 108, such that the first resonant frequency of the first resonant structure 104 is lower when compared to the second resonant frequency of the second resonant structure 108. Specifically, the length L of the first resonant structure 104 is determined based on the first resonant frequency in the first frequency band, while the length (e.g., length L) of the second resonant structure 108 is determined based on the second resonant frequency in the first frequency band.

[0059] FIG. 2 is an exploded view of an antenna device 100 according to an embodiment of the present disclosure. Referring to FIG. 2, an exploded view of the antenna device 100 is shown. As shown, the antenna device 100 includes a radiator 102, a director 106, a first resonant structure 104, and a second resonant structure 108. The antenna device further includes a feed arrangement (not shown) disposed below the radiator 102 and above a ground layer (not shown), and a feed cavity 122 in which the feed arrangement may reside. Furthermore, the ground layer and the feed arrangement may be formed using a printed circuit board, and may further include electrical connections and wiring to enable feeding of power from the feed arrangement to the antenna device 100.

[0060] As further shown, each of the first resonant structure 104 and the second resonant structure 108 includes a number of perforations disposed at different locations on each of the radiating structures 104, 108. As shown, the first resonant structure 104 includes nine perforations disposed throughout the first resonant structure 104. Specifically, each end of the first resonant structure 104 includes two perforations, which may or may not be equally spaced relative to the other. Apart from the perforations at each end of the resonant structure 104, there is a perforation at a substantially central location. Notably, the perforations are disposed at specific locations throughout the resonant structure 104 to accommodate the first set of support tabs 118. The term "support tab" refers to a protrusion of material attached to or extending from any structure, such as the radiator 102 or the resonant structure 104, and is used to hold or secure the structure in a desired position.

[0061] Typically, the plurality of perforations (i.e., nine perforations) in the first resonant structure 104 are configured to receive a first set of support tabs 118 including nine support tabs 118A-I, such as a first support tab 118A, a second support tab 118B, etc. through a ninth support tab (a central support tab). Each of the plurality of perforations (e.g., nine perforations) in the first resonant structure 104 is configured to receive a second end of each of the nine support tabs 118A-I. Typically, the support tabs 118A-I are used to hold the first resonant structure 104 at a distance D from the radiator 102.

[0062] Similarly, the second resonant structure 108 includes five perforations disposed throughout the second resonant structure 108 (similar to the first resonant structure 104). Specifically, each end of the second resonant structure 108 includes a single perforation. Apart from the single perforation at each end of the resonant structure 108, there is a perforation at a substantially central location of the second resonant structure 108. Typically, the plurality of perforations (or the five perforations) are provided to receive a second set of support tabs including five support tabs 120A-E, i.e., the first support tab 120A, the second support tab 120B, etc. through the fifth support tab 120E (the central support tab). Each of the plurality of perforations (e.g., the five perforations) of the second resonant structure 108 is configured to receive a second end of each of the five support tabs 120A-E.

[0063] In particular, the support tabs 118, 120 are formed as an integral part of the support structures 112, 114. In other words, the support tabs 118A-I are part of the first set of support structures 118, and the second set of support tabs 120A-E are part of the second set of support structures 114.

[0064] FIG. 3 illustrates a perspective view of the antenna device 100 and another antenna device 300 (similar to the antenna device 100) according to an embodiment of the present disclosure. Referring to FIG. 3, two antenna devices are shown, i.e., the antenna device 100 and the other antenna device 300, which are separated or separated by a predetermined distance. The antenna device 300 (or the second antenna device) is similar to the antenna device 100 in terms of shape and structure. Typically, the antenna device 300 includes a second radiator 302, a first resonant structure 304 disposed adjacent to the second radiator 302, and a director 306 (like the director 106 of the antenna device 100) disposed at a distance from the second radiator 302. Furthermore, the other antenna device 300 includes a second resonant structure 308 adjacent to the director 306. In particular, the two antenna devices 100, 300 are spaced apart from an enclosing wall (such as the enclosing wall 110), and the distance of the enclosing wall from the antenna devices 100, 300 is adapted based on the implementation. The term "enclosing wall" refers to a wall that encloses one or more antenna devices, preferably made of a conductive material such as metal. It will be appreciated by those skilled in the art that the distance between the two antenna devices and the distance between the antenna devices and the enclosing wall may be varied without limiting the scope of the disclosure. In the implementation, the separation between the two antenna devices, i.e., the antenna device 100 and another antenna device 300, is about 0.6λ. i In this case, λ i is the central wavelength of the antenna device, λ centralThe first antenna device 100 and the other antenna device 300 are configured to operate in a first frequency band and a second frequency band, respectively. Typically, the antenna device 100 includes a resonant structure 104 and a resonant structure 108 configured to filter one or more sub-bands of the first frequency band, in which case the other antenna device 300 may operate. Similarly, the second antenna device 300 includes a first resonant structure 304 and a second resonant structure 308 configured to filter one or more sub-bands of the second frequency band, in which case the antenna device 100 may operate.

[0065] According to an embodiment, the first frequency band and the second frequency band each include a plurality of sub-bands, in which the sub-bands of the first frequency band are interleaved with the sub-bands of the second frequency band. Typically, the sub-bands of each frequency band, such as the first frequency band and the second frequency band, at least partially overlap with each other. Furthermore, the operating sub-bands of each frequency band may alternate with each other. The term "operating sub-band" refers to a sub-band operating in some antenna device. In one example, the first sub-band of the first frequency band may be accompanied by the first sub-band or the second sub-band of the second frequency band. In an exemplary scenario, a first frequency band ranging from 1.4 GHz to 2 GHz may include multiple sub-bands, such as a first sub-band ranging from 1.71 GHz to 1.785 GHz and a second sub-band ranging from 1.805 GHz to 1.88 GHz, and a second frequency band ranging from 1.6 GHz to 2.4 GHz may include multiple sub-bands, such as a third sub-band ranging from 1.92 GHz to 1.98 GHz and a fourth sub-band ranging from 2.11 GHz to 2.17 GHz, where interleaved sub-bands exist in the overlapping region of the two frequency bands, and the sub-bands operating within the two frequency bands are defined by resonant frequencies associated with the resonant structures 104 and 108. The resonant frequencies associated with the resonant structures 104 and 108 may be selected based on a desired band of operation. Each of the multiple sub-bands, such as the first, second, third, and fourth sub-bands, may exist in alternative forms based on various implementation objectives. In one example, the first sub-band may be used for uplink communications, while the fourth sub-band may be used for downlink communications.

[0066] According to an embodiment, the resonant frequency (such as the first resonant frequency) is determined based on a second frequency band associated with another antenna device 300 (also referred to as the second antenna device) located adjacent to the antenna device 100. The first resonant frequency is determined based on the second frequency band of the other antenna device 300. Typically, the resonant frequency, such as the first resonant frequency associated with the first resonant structure 104, is based on a sub-band within the second frequency band of the other antenna device 300. Similarly, the resonant frequency, such as the second resonant frequency associated with the second resonant structure 304, is based on a sub-band within the first frequency band. The selective implementation of the two antenna devices allows each antenna device, i.e. the antenna device 100 and the other antenna device 300, to operate together without degrading performance by rejecting a sub-band within the first frequency band or the second frequency band, in which case the coupling between the two antenna devices 100, 300 is high.

[0067] According to an embodiment, the first antenna device 100 and the other antenna device 300 may be configured to operate in combination as a system with a duplexer. The first resonant structure 104 and the second resonant structure 304 may be configured to operate in combination as a duplexer during operation of the two antenna devices. The term "duplexer" refers to an electronic device that allows bidirectional (duplex) communication in a single path. Here, the resonant structures 104, 304 enable the antenna devices 100, 300 to operate together, allowing the antenna devices 100, 300 to perform bidirectional communication (e.g., uplink and downlink) simultaneously within a single frequency band. In an implementation, the antenna device 100 is capable of performing a downlink in a first frequency band, and the other antenna device 300 is capable of performing an uplink in a second frequency band. Alternatively, the uplink and downlink operations may be reversed. Advantageously, the antenna device 100 does not require any additional components (such as duplexers) for operation, thereby reducing overall size and complexity.

[0068] 4 is a block diagram of an array of antenna devices 400 according to an embodiment of the present disclosure. The array of antenna devices 400 may be any of the antenna devices 100 or antenna The antenna device 300 (shown and described in connection with FIGS. 1-3 ) should be understood in combination with the antenna device 300 (shown and described in connection with FIGS. 1-3 ). The array 400 includes two or more antenna devices (such as the antenna device 100 and another antenna device 300). The array 400 of antenna devices includes a plurality of antenna devices arranged in an array or grid format. For example, the array 400 of antenna devices includes an antenna device 402 (similar to the antenna device 100) and an antenna device 404 (similar to the another antenna device 300). The antenna devices 402, 404 may be connected to a single receiver or transmitter by a feed line that provides power to such antenna devices 402, 404 in a specific phase relationship to operate together as a single antenna. As mentioned herein, the antenna device 100 may operate at dual frequencies in a first frequency band, and similarly, the another antenna device 300 may operate at dual frequencies in a second frequency band. Thus, the array 400 of antenna devices may operate at one or both of the dual frequencies simultaneously. Further, each antenna device 402, 404 in the array 400 may be configured to either transmit or receive an electromagnetic signal (such as the electromagnetic signal radiated by the radiator 102).

[0069] The array of antenna devices 400 may include two or more antenna devices such as the antenna device 100. In such a case, the array of antenna devices 400 may be operable in one or more frequency bands (e.g., a first frequency band, a second frequency band), i.e., one, two, or more than one frequency band. Furthermore, the two or more antenna devices 402, 404 of the array of antenna devices 400 may be connected to multiple receivers or transmitters via feed lines in a feeding arrangement, which is configured to provide power to such two or more antenna devices 402, 404 in a specific phase relationship to operate together as a single antenna or multiple antennas to communicate with multiple wireless communication devices. Furthermore, examples of multiple wireless communication devices include, but are not limited to, user equipment (e.g., smartphones), customer premises equipment, repeater devices, fixed wireless access nodes, and other communication devices or telecommunication hardware.

[0070] According to an embodiment, the array of antenna devices 400 includes a first antenna device 402 operating in a first frequency band and having a first resonant structure (such as resonant structure 104) tuned to a first resonant frequency, and a second antenna device 404 operating in a second frequency band and having a second resonant structure (such as resonant structure 304) tuned to a second resonant frequency. In an embodiment, the first antenna device 402 operating in the first frequency band and the second antenna device 404 operating in the second frequency band form a dual band array 400, where the first resonant frequency of the first antenna device 402 defines a rejection sub-band in the first frequency band of the first antenna device 402 and the second resonant frequency of the second antenna device 404 defines a rejection sub-band in the second frequency band of the second antenna device 404. In particular, the two antenna devices 402, 404 have interleaved frequency bands and are closely spaced, so that coupling between the two antenna devices 402, 404 tends to be high, and as a result, the antenna elements that make up the array 400 are tuned in a broadband manner.

[0071] In the implementation, the first antenna device 402 operating in a first frequency band is detuned at a first resonant frequency based on an operating sub-band of the second frequency band of the second antenna device 404. For example, a first sub-band ranging from 1.8 GHz to 1.9 GHz is rejected by the first antenna device 402. In other words, the first antenna device 402 is detuned at a first resonant frequency associated with a first resonant structure in the first operating sub-band of the second antenna device 404.

[0072] Conversely, the second antenna device 404 operating in the second frequency band is detuned in a second resonant frequency associated with the second resonant structure based on the operating sub-band of the first frequency band of the first antenna device 402. For example, in the second frequency band ranging from 1.8 GHz to 2.2 GHz, a first sub-band ranging from 1.7 GHz to 1.8 GHz and a second sub-band ranging from 1.9 GHz to 2.0 GHz are rejected by the second resonant structure of the second antenna device 404. In other words, the second antenna device 404 is detuned in the first operating sub-band and the second operating sub-band of the first antenna device 402.

[0073] FIG. 5 is an example frequency band 500 of an array 400 of antenna devices 402, 404 according to an embodiment of the present disclosure. FIG. 5 will be described in conjunction with elements from FIGS. 1, 2, 3, and 4. Referring to FIG. 5, a graphical representation 500 of an example first frequency band 504 and an example second frequency band 506 of an array 400 of antenna devices 402, 404 is shown. The operating characteristics of the first antenna device and the second antenna device, i.e., the type of operation performed by each of the two antenna devices, are also shown. In an implementation, the first frequency band 504 includes a first sub-band 504A, where the first antenna device performs uplink operations, and the second frequency band 506 includes a second sub-band 506A, where the second antenna device performs downlink operations. An "overlap region" 502 represents an area where the first frequency band 504 and the second frequency band 506 coincide with each other. Alternatively, the overlap region 502 is formed by a partial overlap of the first frequency band 504 and the second frequency band 506, the overlap region 502 including the first overlap region 502A and the second overlap region 502B, and further, the first antenna device performs uplink operations in the second overlap region 502B and the second antenna device performs downlink operations in the first overlap region 502A. In particular, the sub-overlap regions 502A, 502B included in the overlap region 502 are also sub-bands of the first frequency band 504 and the second frequency band 506. In one example, the first frequency band 504 includes the Digital Cellular System (DCS) 1800 MHz band and the second frequency band 506 includes the International Mobile Telecommunications (IMT) 2100 MHz band. Furthermore, the two antenna devices in operation may experience coupling in or near the overlap region 502.

[0074] Thus, in order to eliminate coupling between the two antenna devices in operation, one or more sub-bands from each of the first frequency band 504 and the second frequency band 506 are rejected by the resonant structures of the first and second antenna devices, respectively. Specifically, in the first frequency band 504, a sub-band (e.g., first overlap region 502A) ranging from 1.8 GHz to 1.9 GHz is rejected by the first antenna device, allowing the second antenna device to operate in the rejected sub-bands without coupling. Similarly, in the second frequency band 506, a sub-band (e.g., first sub-band 504A) ranging from 1.7 GHz to 1.8 GHz and a sub-band (e.g., second overlap region 502B) ranging from 1.9 GHz to 2.0 GHz are rejected by the second antenna device, allowing the first antenna device to operate in the rejected sub-bands.

[0075] According to the embodiment, the first frequency band 504 and the second frequency band 506 include a plurality of sub-bands including, but not limited to, a first sub-band 504A, a second sub-band 506A, and an overlap region 502. Furthermore, the overlap region 502 includes two sub-bands, namely, a first overlap region 502A and a second overlap region 502B. Furthermore, the sub-bands of the first frequency band 504 are interleaved with the sub-bands of the second frequency band 506 forming the overlap region 502. Alternatively, the sub-bands of the overlap region 502, namely, the first overlap region 502A and the second overlap region 502B, are included within both the first frequency band 504 and the second frequency band 506. Typically, the sub-bands of each frequency band, such as the first frequency band 504 and the second frequency band 506, at least partially overlap each other. Additionally, the operating sub-bands of each frequency band 502, 504 may be alternated with respect to the other.

[0076] According to an embodiment, the first antenna device 402 is configured for uplink and the second antenna device 404 is configured for downlink. Here, the array 400 of antenna devices 402, 404 is configured for uplink and downlink operations. Specifically, uplink operations are performed by the first antenna device 402 and downlink operations are performed by the second antenna device 404. Typically, the uplink and downlink operations performed by the first antenna device 402 and the second antenna device 404, respectively, are performed in different sub-bands of a first frequency band and a second frequency band. In one example, a first frequency band 504 ranging from 1.4 GHz to 2 GHz may include multiple sub-bands, such as a first sub-band 504A ranging from 1.71 GHz to 1.785 GHz and a third sub-band, such as a second overlap region 502B ranging from 1.92 GHz to 1.98 GHz. The second frequency band 506, which ranges from 1.6 GHz to 2.4 GHz, may include a second sub-band, such as a first overlap region 502A, which ranges from 1.805 GHz to 1.88 GHz, and a fourth sub-band, such as a second sub-band 506A, which ranges from 2.11 GHz to 2.17 GHz. Each of the multiple sub-bands, such as the first, second, third, and fourth sub-bands, may be used for various implementation purposes. In one example, the first sub-band 504A and the third sub-band 502B may be used for uplink communication, and the second sub-band 502A and the fourth sub-band 506A may be used for downlink communication by the two antenna devices 402, 404.

[0077] According to an embodiment, the first frequency band 504 overlaps with the second frequency band 506. The first frequency band 504 may differ from the second frequency band 506, and such difference may be substantial or may not be substantial. Furthermore, the first frequency band 504 may at least partially overlap with the second frequency band 506. Thus, the array of antenna devices 400 forms a dual band antenna device, i.e., configured to radiate an electromagnetic signal (e.g., a first electromagnetic signal) simultaneously in two frequency bands 504, 506. In one example, an array 400 including at least a first antenna device (e.g., antenna device 402) operating in a first frequency band, such as 1710-1980 MHz, and at least a second antenna device (e.g., second antenna device 404) operating in 1805 MHz-2170 MHz overlaps in the region from 1805 MHz to 1980 MHz (e.g., overlap region 502).

[0078] FIG. 6A is a graphical representation 600A illustrating a return loss and coupling level c associated with a first antenna device 402 in a first frequency band 504, according to an embodiment of the present disclosure. FIG. 6A will be described with reference to elements from FIGS. 1, 2, 3, 4, and 5. Referring to FIG. 6A, a graphical representation 600A illustrating a return loss and coupling level c associated with a first antenna device (similar to antenna device 100) in a first frequency band 504 is shown. Here, the first antenna device, including two resonant structures (e.g., first resonant structure 104 and second resonant structure 108 of FIG. 1), is configured to reject a sub-band 602 (encircled by a solid line) that spans the range of 1.8 to 1.9 GHz. In particular, the two resonant structures are used together to provide a wider sub-band for the second antenna device (such as the second antenna device 404) to operate, since each resonant structure (such as the first resonant structure 104 and the second resonant structure 108) individually would be too narrow. As a result, the antenna device is detuned to a return loss (RL) worse than -2 dB at frequencies ranging from 1.8 to 1.9 GHz, as shown by the solid line. Furthermore, as shown, the first antenna device is configured to operate in sub-bands within the first frequency band, namely the first sub-band 604A and the second sub-band 604B, in which (or due to) the return loss is very low or negligible. As further shown, the first curve 612A and the second curve 612B show the return loss associated with each polarization in the first antenna device 402. As further shown, a third curve 614 shows the resulting coupling level between the two polarizations at the first antenna device.

[0079] FIG. 6B is a graphical representation 600B illustrating return loss and coupling levels associated with a second antenna device 404 in a second frequency band 506 according to an embodiment of the present disclosure. FIG. 6B will be described with reference to elements from FIGS. 1, 2, 3, 4, 5, and 6A. Referring to FIG. 6B, a graphical representation 600B illustrating return loss and coupling levels associated with a second antenna device (similar to another antenna device 300) in a second frequency band 506 is shown. Here, the second antenna device includes two resonant structures (e.g., the first resonant structure 304 and the second resonant structure 308 of FIG. 3) that are configured to reject a first sub-band 606 (encircled by a solid line) that ranges from 1.7 to 1.8 GHz and a second sub-band 608 (encircled by a solid line) that ranges from 1.9 to 2.0 GHz. In particular, two resonant structures are used respectively to provide two separate sub-bands (encircled by dotted lines) in which the first antenna device operates. As a result, the second antenna device (e.g., second antenna device 404) is detuned to a return loss (RL) worse than -2 dB at frequencies ranging from 1.7 to 1.8 GHz and frequencies ranging from 1.9 to 2.0 GHz, as shown by dashed lines. As further shown, the second antenna device is configured to operate in a sub-band, namely, the third sub-band 610, within the second frequency band 506, in which the return loss is very low or negligible. As further shown, a first curve 616A and a second curve 616B show the return loss associated with each polarization at the second antenna device 404. As further shown, a third curve 618 shows the resulting coupling level between the two polarizations at the second antenna device.

[0080] Referring to Figure 7A, a graphical representation 700A is shown illustrating the mutual coupling between two conventional antenna devices operating without a resonant structure in terms of co-polarization (Copol) coupling and cross-polarization (Xpol) coupling. Figure 7A will be described with reference to elements from Figures 1, 2, 3, 4, 5, 6A, and 6B. Typically, co-polarization refers to the desired polarization of the antenna device, and cross-polarization (Xpol) refers to an orthogonal pair of desired polarizations of the antenna device. The graphical representation 700A represents coupling values ​​(or coupling levels) on the Y-axis with respect to frequency (in gigahertz (GHz)) on the X-axis. The coupling level values ​​related to the co-polarized and cross-polarized curves are represented in decibels (dB). A first co-polarized curve 706A of the first antenna device is represented by a solid line and a second co-polarized curve 706B of the second antenna device 404 is represented by a dotted line. Similarly, a first cross-polarized curve 708A of the first antenna device is represented by a solid line and a second cross-polarized curve 708B of the second antenna device is represented by a dotted line. In particular, the cross-polarized coupling level is smaller than the co-polarized coupling level.

[0081] FIG. 7B is a graphical representation 700B illustrating the effect on antenna coupling between two antenna devices (e.g., first antenna device 100, second antenna device 300) operating in two different frequency bands, such as first frequency band 504, second frequency band 506, respectively, according to an embodiment of the present disclosure. FIG. 7B will be described with reference to elements from FIGS. 1, 2, 3, 4, 5, 6A, 6B, and 7A. Referring to FIG. 7B, a graphical representation 700B is shown illustrating mutual coupling between two antenna devices operating in resonant structures (e.g., first resonant structure 104, second resonant structure 304) in terms of co-polarized (Copol) coupling and cross-polarized (Xpol) coupling. The graphical representation 700B represents coupling levels on the Y-axis versus frequency in gigahertz (GHz) on the X-axis. The coupling level values ​​associated with the co-polarized and cross-polarized curves are represented in decibels (dB). A first curve 716A illustrates a coupling level associated with a first antenna device operating in a first frequency band 504 due to co-polarized (Copol) coupling. Similarly, a second curve 716B illustrates a coupling level associated with a second antenna device operating in a second frequency band 506 due to co-polarized coupling. As further illustrated, a first curve 718A illustrates a coupling level associated with a first antenna device operating in a first frequency band 504 due to cross-polarized (Xpol) coupling. A second curve 718B illustrates a coupling level associated with a second antenna device operating in a second frequency band 506 due to cross-polarized coupling.

[0082] It is clear from Fig. 7B that there is a drop in the value of the coupling levels associated with both the first and second antenna devices due to the presence of the resonant structures. More specifically, the first antenna device is detuned in two sub-bands enclosed by solid lines, namely the second sub-band (e.g. 1.8 GHz to 1.9 GHz) and the fourth sub-band (e.g. 2.1 GHz to 2.2 GHz), and the second antenna device is detuned in two sub-bands enclosed by dotted lines, namely the first sub-band (e.g. 1.7 GHz to 1.8 GHz) and the third sub-band (e.g. 1.9 GHz to 2.0 GHz).

[0083] As shown in relation to and in comparison with FIG. 7A, the first curve 706A and the second curve 706B associated with the conventional antenna device of FIG. 7A operating without a resonant structure have a higher value of co-polarized coupling compared to the first curve 716A and the second curve 716B associated with the two antenna devices operating with a resonant structure. In particular, the reduction in the value of the co-polarized coupling level as shown by 720A, 720B, 720C, 720D can be understood as a result of the specific detuning of the two antenna devices. In particular, the first antenna device detuned at the fourth sub-band, the second sub-band, surrounded by a solid line, shows a reduction in the co-polarized coupling level shown by 720A, 720C, and the second antenna device detuned at the third sub-band, the first sub-band, surrounded by a dotted line, shows a reduction in the co-polarized coupling level shown by 720B, 720D.

[0084] The reduction in the value of the co-polarized coupling represents a significant improvement in the performance of the two antenna devices due to the reduced coupling level. Advantageously, a low value of coupling is achieved while the first antenna device and the second antenna device are operating together. In other words, only a small amount of energy is transferred from one antenna device to the other antenna device. As a result, the two antenna devices can function or operate at a very close spacing, minimizing the effects of antenna placement.

[0085] In an embodiment, the antenna device 100 and the antenna device 300 may each include two or more resonant structures (e.g., resonant structure 104, resonant structure 304) operating in either the first frequency band or the second frequency band. Specifically, the antenna device 100 or another antenna device 300 may include either three or four resonant structures arranged in pairs of two resonant structures at each site (i.e., radiator 102 or director 106) or singly at either site. The two or more resonant structures may be configured to operate separately to detune or filter individual sub-bands in either frequency band, or to operate in conjunction to detune or filter a common sub-band in a more efficient manner. In an exemplary scenario, the antenna device 100 includes a total of three resonant structures, where two of the three resonant structures are located on the top and bottom of either the radiator 102 or the director 106, in other words, two resonant structures are located on the radiator 102 and the third resonant structure is located on the director 106, or vice versa. In another exemplary scenario, another antenna device 300 includes a total of four resonant structures arranged in pairs at each site, i.e., two resonant structures are located on the top and bottom of the radiator 302 and another two resonant structures are located on the top and bottom of the director 306. Beneficially, two or more resonant structures (such as the antenna device 100) may be implemented separately to individually filter two or more smaller sub-bands in either the first or second frequency band (e.g., for another antenna device 300 to operate), or two or more resonant structures (such as the first antenna device) may be implemented together to filter a larger sub-band in either the first or second frequency band (e.g., for another antenna device 300 to operate).

[0086] 8-11 are alternative embodiments of resonant structures of antenna devices according to various embodiments of the present disclosure. FIG. 8-11 is described in relation to elements from FIG. 1, 2, 3, 4, 5, 6A, 6B, 7A, 7B. Referring to FIG. 8-11, alternative embodiments of resonant structures (e.g., resonant structures 104, 108, 304, 308, etc.) of an antenna device (such as antenna device 100 or another antenna device 300) are shown. In particular, the alternatives are alternative implementations or possible configurations of the resonant structures that may be applied to an antenna device such as antenna device 100 or antenna device 300 depending on implementation requirements, without limiting the scope of the disclosure. Typically, the size and shape of the resonant structures are changed to set the resonant frequency depending on implementation requirements. It will be understood by those skilled in the art that the change in the shape and size of the resonant structure does not limit its function or application, but only limits the associated resonant frequency. In particular, the change in the resonant frequency is brought about by the change in the size and shape of the stubs associated with the resonant structure. The term "stub" refers to a length of transmission line or waveguide that is connected to one end of an antenna device. Traditionally, stubs are used in antenna impedance matching circuits, frequency selective filters, and resonant circuits for UHF electronic oscillators and RF amplifiers. In particular, stub implementations are used to match a transmission line to an antenna or load, where the match depends on the spacing between the two wires of the stub and the point where the transmission line is connected to the stub.

[0087] Referring to FIG. 8, a resonant structure 800 having dual coupled stubs is shown, where the length of the stubs is varied to set the resonant frequency of the resonant structure 800 .

[0088] 9, there is shown a resonant structure 900 having a double coupled stub with an additional resonant square 902 in the center of the resonant structure, where the length of the stub and the size of the resonant square 902 are varied to set the resonant frequency of the resonant structure 900.

[0089] Referring to FIG. 10, a star-shaped resonant structure 1000 is shown. As shown, the star-shaped resonant structure has seven ends that make up four stubs, and each stub may have a different length. In an implementation, a first stub 1002, as depicted by line 1000A, has a different length from a second stub 1004, as depicted by line 1000B, and the different stub lengths of the first stub 1002 and the second stub 1004 provide the resonant structure 1000 with dual resonance (or dual resonant frequencies). Typically, each stub (such as the first stub 1002, the second stub 1004, etc.) has a different length from each other, causing the resonant structure 1000 to provide different resonant frequencies.

[0090] 11, a resonant structure 1100 having a cross shape is shown. As shown, the cross-shaped resonant structure 1100 (similar to resonant structures 104 or 108 of FIG. 1) has two stubs configured as a cross or cross-shaped structure, where the length of the cross (or cross-shaped structure) sets the resonant frequency of the resonant structure 1100.

[0091] Modifications to the embodiments of the present disclosure described above are possible without departing from the scope of the present disclosure, which is defined by the appended claims. Words such as "including," "comprising," "incorporating," "having," and "is," used to describe and claim the present disclosure, are intended to be construed in a non-exclusive manner, i.e., allowing for the presence of items, components, or elements not expressly described. References to the singular are also construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance, or exemplar." Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments and / or does not exclude the incorporation of features from other embodiments. The word "optionally" is used herein to mean "provided in some embodiments and not provided in other embodiments." It will be appreciated that certain features of the present disclosure that are described in the context of separate embodiments, for clarity, may also be provided in combination in a single embodiment. Conversely, for brevity, various features of the invention that are described in the context of a single embodiment may also be provided separately or in any suitable combination, as appropriate, in any other described embodiment of the present disclosure.

Claims

1. 13. An antenna device comprising: a radiator configured to radiate electromagnetic signals in a direction parallel to a radiation axis of the antenna device and having a substantially planar shape perpendicular to the radiation axis; a first resonant structure adjacent to the radiator, the first resonant structure having a substantially planar cross-shaped structure parallel to the radiator, the first resonant structure acting as a parasitic element; a director having a planar structure disposed parallel to and spaced from the radiator; at least one second resonant structure adjacent to the director and configured to act as a parasitic element; the radiator is a patch antenna and is configured to radiate the electromagnetic signal in a first frequency band, the first resonant structure has a substantially planar shape parallel to the director and is configured to have a first resonant frequency in the first frequency band, and the second resonant structure has a second resonant frequency in the first frequency band and is configured to be smaller than the first resonant structure.

2. 2. The antenna device of claim 1, wherein the first resonant structure is disposed in a reactive near field of the radiator.

3. 3. The antenna device according to claim 1, wherein the distance between the radiator and the first resonant structure is less than the central wavelength λ of the first frequency band. central and is determined based on 0.001 to 0.1 λ central The antenna device is determined to be between

4. 4. An antenna device according to any one of claims 1 to 3, wherein the first resonant structure is formed from one of a metal sheet, a printed circuit board, or a substrate having a metallized foil; and is attached to a radiator by one or more supports or to a substrate laminated to the radiator.

5. 5. An antenna device according to claim 1, wherein the shape of the first resonant structure is symmetrical about a centre point of the first resonant structure.

6. 6. An antenna device according to any one of the preceding claims, wherein a length of the first resonant structure is determined based on the first resonant frequency.

7. 7. An antenna device as claimed in any one of claims 1 to 6, wherein the first resonant frequency is determined based on a second frequency band radiated by another antenna device arranged adjacent to the antenna device.

8. 8. An array of antenna devices comprising two or more antenna devices according to any one of claims 1 to 7.

9. 9. The array of claim 8, a first antenna device operating in the first frequency band, the first antenna device having the first resonant structure tuned to the first resonant frequency; and a second antenna device operating in a second frequency band, the second antenna device having the second resonant structure tuned to the second resonant frequency; wherein the first resonant frequency is determined based on the second frequency band, and the second resonant frequency is determined based on the first frequency band.

10. 10. The array of claim 9, wherein the first antenna device is configured for an uplink and the second antenna device is configured for a downlink.

11. 11. An array according to claim 9 or 10, wherein the first frequency band overlaps with the second frequency band.

12. 12. The array of claim 9, wherein the first frequency band and the second frequency band each include a plurality of sub-bands, the sub-bands of the first frequency band being interleaved with the sub-bands of the second frequency band.

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