WO2020133997A1

WO2020133997A1 - Selectively driven ultra-wideband antenna arrays

Info

Publication number: WO2020133997A1
Application number: PCT/CN2019/093958
Authority: WO
Inventors: Ahmed Hassan Abdelaziz ABDELRAHMAN; Zhengxiang Ma
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2018-12-28
Filing date: 2019-06-29
Publication date: 2020-07-02

Abstract

A antenna array operable in an ultra-wide bandwidth, in which a ratio between a highest designed operating frequency and a lowest designed operating frequency exceeds 2: 1, includes antenna elements arranged in rows along a planar surface. The antenna elements have spacing between adjacent elements determined in accordance with a wavelength of the highest designed operating frequency. A feeding network is configured to feed different groups of antenna elements of the antenna array using signals in different frequency bands. An antenna element of the antenna array may be fed by a signal in one frequency band, by signals in more than one frequency band, or may not be fed at all.

Description

Selectively Driven Ultra-Wideband Antenna Arrays

CROSS-REFERENCE TO RELATED APPLIATIONS

This application claims priority to U.S. Provisional Patent Application Serial No. 62/786,217 that was filed on 28 December 2018 and entitled “Selectively Driven Ultra-Wideband Antenna Arrays” , the disclosure of which is incorporated herein in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to antenna systems, and, in particular embodiments, to selectively driven ultra-wideband antenna arrays.

BACKGROUND

Ultra-wideband (UWB) antennas and arrays are becoming increasingly important for high data rate communications, addressing spectrum congestion, and for high-resolution radar and tracking systems. For example, tightly coupled arrays (TCAs) are of particular interest due to their low-profile and UWB bandwidth capability. This capability provides considerable advantage over other wideband antenna arrays based on heavy ferrite ground planes, or large, non-conformal antenna elements.

SUMMARY

According to one aspect of the present disclosure, there is provided an apparatus that includes a first antenna array operable in a bandwidth in which a ratio between a highest designed operating frequency and a lowest designed operating frequency exceeds 2: 1. The first antenna array includes a plurality of antenna elements that is arranged in a number of rows along a planar surface, and the plurality of antenna elements has spacing between adjacent elements determined in accordance with a wavelength of the highest designed operating frequency. The apparatus further includes a feeding network configured to feed a first group of antenna elements of the plurality of antenna elements using signals in a first frequency band of a plurality of frequency bands, and to feed a second group of antenna elements of the plurality of antenna elements using signals in a second frequency band of the plurality of frequency bands, without feeding at least one antenna element in the first group of antenna elements using a signal in the second frequency band. By selecting limits as to highest designed (or planned) operating frequency and lowest designed (or planned) operating frequency, an antenna array can be provided that is optimized to receive and to transmit signals in a desired bandwidth.

According to another aspect of the present disclosure, there is provided a method that includes providing a first antenna array of a device for wireless communications in a bandwidth in which a ratio between a highest designed operating frequency and a lowest designed operating frequency exceeds 2: 1. The first antenna array includes a plurality of antenna elements that are arranged in a number of rows along a planar surface, and the plurality of antenna elements has spacing between adjacent elements determined in accordance with a wavelength of the highest operating frequency. The method further includes feeding, using a feeding network, a first group of antenna elements of the plurality of antenna elements using signals in a first frequency band of a plurality of frequency bands, and feeding, using the feeding network, a second group of antenna elements of the plurality of antenna elements using signals in a second frequency band of the plurality of frequency bands, without feeding at least one antenna element in the first group of antenna elements using a signal in the second frequency band.

In the above aspects of the present disclosure, a distance between two adjacent antenna elements in the first group of antenna elements may satisfy a requirement predetermined based on a wavelength of the first frequency band and the highest operating frequency. In one embodiment, the spacing between adjacent elements of the first antenna array may be in a range from 0.2λ to λ, and λ is the wavelength of the highest operating frequency. The first group of antenna elements may include all antenna elements of the first antenna array, or include a portion of antenna elements of the first antenna array. In one embodiment, at least one antenna element of the plurality of antenna elements is not fed. In one embodiment, the second group of antenna elements may be fed for transmission according to frequency division duplex (FDD) , and a first antenna element of the first antenna array not belonging to the second group of antenna elements may be fed by a signal in the second frequency band for reception according to the FDD.

In the above aspects of the present disclosure, the feeding network is configured to feed different groups of antenna elements using feed signals in different frequency bands. An antenna element of the first antenna array may be fed by a signal in one frequency band, by signals in more than one frequency band, or may not be fed at all. That is, not every antenna element of the first antenna array needs to be fed for all frequency bands in which the first antenna array is configured to operate. As a result, the number of signals in different bands that need to be fed to an antenna element of the first antenna array may be reduced, and the number of power splitter required for feeding the first antenna array may thus be reduced. This may in turn greatly reduce antenna feeding system complexity, lower antenna feeding cost, and reduce antenna system size.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a diagram of an embodiment of a wireless network;

FIG. 2 illustrates a diagram of a known antenna system;

FIG. 3 illustrates a diagram of an embodiment antenna system;

FIG. 4 illustrates a diagram of another embodiment antenna system;

FIG. 5 illustrates a diagram of another embodiment antenna system;

FIG. 6 illustrates a diagram of another embodiment antenna system;

FIG. 7 illustrates a diagram of another embodiment antenna system;

FIG. 8 illustrates a flowchart of an embodiment method for feeding an antenna array;

FIG. 9 illustrates a flowchart of an embodiment method for providing an antenna system;

FIG. 10 illustrates a block diagram of an embodiment processing system; and

FIG. 11 illustrates a block diagram of a transceiver.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Ultra-wide bandwidth (UWB) antenna arrays have shown benefits in telecommunications, e.g., providing high data rate, reducing traffic congestions, and increasing communications coverage. Tightly coupled array (TCA) antennas are one of candidates for UWB antenna arrays. However, a TCA requires that each array element of the TCA be fed by signals in all frequency bands for transmission and reception. This complicates the antenna system structure and also increases feeding cost.

Aspects of the present disclosure provide embodiment antenna systems operable in a UWB and methods for feeding antenna arrays. As used herein, the terms “ultra-wide bandwidth” , “UWB” and ultra-wide band” pertain to a bandwidth in which a ratio of the highest operating frequency to the lowest operating frequency exceeds 2: 1. An embodiment antenna system includes an antenna array and a feeding network for feeding the antenna array for communications. The antenna array includes antenna elements having spacing between adjacent elements determined in accordance with a wavelength of the highest operating frequency. The feeding network is configured to feed different groups of antenna elements using feed signals in different frequency bands. An antenna element of the antenna array may be fed by a signal in one frequency band, by signals in more than one frequency band, or may not be fed at all. That is, not every antenna element of the antenna array needs to be fed for all frequency bands in which the antenna array is configured to operate. As a result, the number of signals in different bands that need to be fed to an antenna element may be reduced, and the number of power splitter required may thus be reduced. This may in turn greatly reduce antenna system complexity, lower the cost for antenna feeding, and reduce sizes of antenna systems. Moreover, by selecting limits as to highest designed (or planned) operating frequency and lowest designed (or planned) operating frequency, an antenna array can be provided that is optimized to receive and to transmit signals in a desired bandwidth. The embodiments may be applied to antenna systems with reduced antenna feeding cost and reduced antenna system sizes. The embodiments may also be applied for frequency division duplex (FDD) communications, where a first group of antenna elements is fed for transmission in a frequency band, and a second group of antenna elements is fed for receiving in the frequency band.

FIG. 1 illustrates a network 100 for communicating data. The network 100 comprises a base station 110 having a coverage area 112, a plurality of mobile devices 120, and a backhaul network 130. As shown, the base station 110 establishes uplink (dashed line) and/or downlink (dotted line) connections with the mobile devices 120, which serve to carry data from the mobile devices 120 to the base station 110, and vice-versa. Data carried over the uplink/downlink connections may include data communicated between the mobile devices 120, as well as data communicated to/from a remote-end (not shown) by way of the backhaul network 130. As used herein, the term “base station” refers to any component (or collection of components) configured to provide wireless access to a network, such as an enhanced base station (eNB or gNB compliant with various 4G and 5G standards promulgated by 3GPP, and evolutions of such standards) , a macro-cell, a femtocell, a Wi-Fi access point (AP) , or other wirelessly enabled devices. Base stations may provide wireless access in accordance with one or more wireless communication protocols, e.g., long term evolution (LTE) , LTE advanced (LTE-A) , 3GPP Rel. 15 and subsequent release, High Speed Packet Access (HSPA) , Wi-Fi 802.11a/b/g/n/ac, ax and other 802.11xx standards. As used herein, the term “mobile device” refers to any component (or collection of components) capable of establishing a wireless connection with a base station, such as a user equipment (UE) , a mobile station (STA) , and other wirelessly enabled devices. In some embodiments, the network 100 may comprise various other wireless devices, such as relays, low power nodes, etc.

It would be desirable for a base station to include antennas that provide communications in frequencies of an ultra-wide bandwidth (UWB) . In this case, the base station may be able to support communications in different communications bands. This may help reduce traffic congestions, and increase communications coverage. UWB antennas and arrays are becoming increasingly desirable for various communication systems, such as high-resolution radar and tracking systems, high data rate telecommunication systems, and multi-waveform, multi-function front-ends. As used herein, the terms “ultra-wide bandwidth” , “UWB” and ultra-wide band” pertain to a bandwidth in which a ratio of the highest operating frequency to the lowest operating frequency is greater than 2: 1. Tightly coupled array (TCA) antennas have emerged as candidates for UWB multifunctional antenna applications. TCAs are generally based on extending an effective length of array elements through strong mutual couplings with neighboring elements, which may imitate a conventional element length required for low frequency bands.

FIG. 2 illustrates a diagram of an example antenna system 200. The antenna system 200 includes a TCA 210 and a feeding network 220 for feeding the TCA 210. The TCA 210 includes a plurality of antenna elements 212, indicated by individual elements E ₁₁, E ₁₂, …E ₄₄, that are arranged in a plurality of rows 213 and columns 215. Each element 212 of the TCA 210 is represented by E _ij, where i = 1, 2, ..., n representing the ith row of the TCA 210, and j = 1, 2, ..., m representing the jth column of the TCA 210. E _ij represents the element in the ith row and the jth column of the TCA 210. The antenna elements of the array 210 are equally spaced and closely arranged to one another on a planar surface, so that the array of antenna elements is tightly coupled electrically, magnetically, or both. In some examples, two antenna elements are tightly coupled when coupling strength between the two antenna elements is greater than -16dB. In a typical example, spacing of two neighboring array elements in the same row or column, e.g., spacing 214 between elements E ₁₂, E ₁₃ or spacing 216 between elements E ₁₂, E ₂₂, may be equal to half of a wavelength at the highest designed (planned) operating frequency of the TCA. That is, the spacing is λ _h/2, where λ represents a wavelength, and λ _h represents a wavelength of the highest designed operating frequency for which the TCA is designed. In this regard, it is to be appreciated that TCAs can be provided for specific wavelengths or wavelength bands, in which case element spacing is provided accordingly. Neighboring array elements in the same row may be coupled, electrically, magnetically, or both, more tightly than neighboring array elements in adjacent rows. Such a TCA has demonstrated features such as low profile (or low height) , high antenna efficiency, and small array areas or sizes that are of potential benefit for communications, including UWB. For example, TCA in the art have demonstrated a bandwidth exceeding 4: 1 (which is a ratio of a highest frequency to a lowest frequency) . Spacing between a TCA and its associated electrical ground may merely be one-tenth of a wavelength of the lowest frequency of operation (i.e., λ/10) . Radiation efficiencies may be greater than 50%across a frequency range of a TCA antenna.

The antenna elements may be in the form of small dipoles, arranged to form a tightly coupled dipole array (TCDA) . The dipoles are capacitively coupled, and placed above a conducting ground plane. Communications using the TCDA in UWB may be achieved by tuning capacitive gaps between neighboring dipole tips. This makes it possible to support an almost uniform current along the coupled dipoles across a wide frequency range so that the radiation resistance stays constant.

FIG. 2 illustrates a 4x4 TCA (i.e., 4

rows

213 and 4 columns 215, thus including 16 antenna elements 212 (E ₁₁ -E ₄₄) in total) , for illustrative purposes. However, TCAs may vary in size and configuration, such as 4x6, 8x8, 66x16, etc. Each of the antenna elements 212 has a respective feed port, i.e., P1-P16, by which the antenna elements 212 are respectively fed with feed signals.

Conventionally, for a TCA operating at multiple different frequency bands, each of the array elements of the TCA is fed at all of the multiple frequency bands for transmission and reception. For example, if the TCA 210 operates in N frequency bands, each antenna element 212 is fed by a combination of N signals from the N respective frequency bands. A combining network is provided for each antenna element, which combines N signals at the N frequency bands to generate a combined feed signal, and feeds the combined feed signal to each antenna element through a respective feed port. Thus, for feeding the 16 elements of

TCA

210, 16 combining networks are needed. Each combining network may have a number of input nodes for receiving a number of feed signals in different frequency bands. The number of input nodes may be equal to the number of frequency bands that the TCA may operate. FIG. 2 shows a combining network 1 (222) that has N input nodes I ₁, I ₂, ... I _N. The combining network 222 combines N signals S ₁₁, S ₂₁, ..., S _N1 in the N frequency bands and feeds a combined signal to the feed port P1 for antenna element E ₁₁. Similarly, a combining network 2 (224) combines N signals S ₁₂, S ₂₂, ..., S _N2 in the N frequency bands (received from N input nodes I ₁, I ₂, ... I _N of the combining network 224) and feeds a combined signal to the feed port P2 for antenna element E ₂₁. A combining network 16 (226) combines N signals S ₁₁₆, S ₂₁₆, ... S _N16 in the N frequency bands and feeds a combined signal to the feed port P16 for antenna element E ₁₄. In this example, Sij represents a feed signal in the ith frequency band for feeding feed port Pj, where i = 1, 2, ..., N, representing N frequency bands, and j = 1, 2, ..., 16, representing 16 feed ports of the TCA 210. All the other antenna elements of the TCA 210 are fed similarly. For example, for element E ₂₃ having the feed port P11, a combining network 11 is provided, which combines N signals S ₁₁₁, S ₂₁₁, ..., S _N11, and feeds a combined feed signal to the feed port P11.

Consequently, as the size of a TCA increases, i.e., the number of antenna elements to be fed increases, an increasing number of power splitters will be required to generate feed signals for feeding the TCA in different frequency bands using combining networks. This complicates the antenna system structure and also increases cost for feeding..

Aspects of the present disclosure provide embodiment antenna systems operable in a UWB and methods for feeding antenna arrays of the antenna systems. As discussed above, a UWB in this disclosure refers to a bandwidth in which a ratio of the highest designed (planned) operating frequency to the lowest designed (planned) operating frequency exceeds 2. The antenna arrays may have low profile, and provide high antenna efficiency. According to some embodiments, an antenna array may be configured to operate in the UWB including multiple frequency bands, and spacing between adjacent antenna elements may be determined based on the wavelength of the highest operating frequency. Different groups of antenna elements in the antenna array may be selected and fed by feed signals of different frequency bands using a feeding network. An antenna element may not be fed, fed by a signal of one band, or fed by signals of multiple bands. As a result, the number of signals in different bands that need to be combined for feeding an antenna element may be reduced, and the number of power splitter required may thus be reduced. This may in turn greatly reduce antenna system complexity, lower the cost for antenna feeding, and reduce size of antenna systems. The embodiments may be used to increase the bandwidth of base station antennas to cover all sub-6GHz cellular bands within same antenna array aperture. The embodiments may also be applied to ultra-wideband massive multi-input and multi-output (MIMO) base station antennas.

FIG. 3 illustrates a diagram of an embodiment antenna system 300. The antenna system 300 includes an antenna array 310 and a feeding network 320 for feeding the antenna array 310. The antenna array 310 is operable in the UWB. That is, the antenna array may be configured to operate in a bandwidth having a ratio of the highest operating frequency to the lowest operating frequency of the antenna array that is greater than 2: 1. For example, the antenna array 310 is operable at multiple frequency bands, where a ratio of the highest operating frequency to the lowest operating frequency among the multiple frequency bands is greater than 2:1. Examples of a frequency band may include 700MHz, 900 MHz, 1.7GHz, 1.8GHz, 2.1GHz, 2.6GHz, 3.5GHz, or 4.9 GHz. The antenna array 310 includes a plurality of antenna elements 312, indicated by individual elements E ₁₁, E ₁₂, …E ₄₄, that are arranged in a plurality of rows 313 and columns 315 along a planar surface. An antenna element 312 of the antenna array 310 herein is referred to as a physical antenna radiating element. Throughout this disclosure, the terms of “antenna element” , “array element” , and “element” are used interchangeably. FIG. 3 illustrates a 4x4 antenna array including 16 elements. However, those of ordinary skill in the art would recognize that the antenna array 310 may have various sizes (i.e., having various numbers of rows and columns) . For example, the antenna array 310 may be an n*m array (i.e., having n rows and m columns) , such as 4x4, 6x6, 16x16, 66x16, 64x64, etc. For the convenience of illustration, each array element of the antenna array 310 is represented by E _ij, where i = 1, 2, ..., n representing the ith row of the antenna array 310, and j = 1, 2, ..., m representing the jth column of the antenna array 310. E _ij represents the element in the ith row and the jth column of the antenna array 310.

The antenna elements 312 of the antenna array 310 are equally spaced. Spacing of antenna elements of an antenna array may be referred to as spacing of the antenna array in the present disclosure, and may be defined as a distance between two adjacent antenna elements in the same row or column of the antenna array (e.g., as shown by spacing 314 between elements E ₁₂ and E ₁₃ in the first row, or spacing 316 between elements E ₁₂ and E ₂₂ in the second column) . In some embodiments, spacing of an antenna array may be determined based on the wavelength of the highest operating frequency of the antenna array. For example, the spacing of the antenna array 310 may be in a range of {0.2λ _h, λ _h} , where λ _h is the wavelength of the highest operating frequency of the antenna array 310. In this case, the spacing may be represented by s = α*λ _h, where s represents the spacing of the antenna array 310, and α is a coefficient having a value from 0.2 to 1. In general, the spacing of an antenna array may be determined such that the antenna array provides required beam forming performance for communications. Although the antenna array 310 is illustrated similarly to the TCA 210 in FIG. 2, the antenna array 310 is merely illustrated in such a way for illustrative convenience. The antenna array 310 may be a TCA, a tapered slot antenna (TSA) array, or other applicable antenna arrays operable in UWB.

Each of the antenna elements 312 has a corresponding feed port for receiving feed signals. FIG. 3 illustrates 16 feed ports P1, P2, ..., P16 corresponding to the 16 respective antenna elements 312. The antenna array 310 may be configured to operate in one or more frequency bands (i.e., N bands, where N is an integer greater than or equal to one) . In this example, N = 3, i.e., the antenna array 310 is configured to operate in three frequency bands (i.e., bands 1-3) corresponding to operating frequencies f1, f2, and f3, respectively. The operating frequency f1 is the highest frequency among f1, f2, and f3, f2 = 1/2 *f1, and f3 = 1/4 *f1. The three frequencies correspond to wavelengths of λ ₁, λ ₂, and λ ₃, respectively, λ ₁= λ _h, λ ₂ = 2λ ₁ and λ ₂ = 4λ ₁ . The spacing of the antenna array 310 is s = α*λ ₁, and α is in a range of {0.2, 1} .

The feeding network 320 includes 16 combining networks 322-332 connected to the 16 feed ports P1-P16, respectively, for feeding the corresponding antenna elements. Thus, each element has a feed port, and each feed port is associated with a combining network. Each of the combining networks includes a number of input ports for receiving feed signals. The number of input nodes of a combining network may be equal to or greater than the number of frequency bands that the antenna array may operate. In this example, each combining network includes three input nodes I ₁-I ₃ for receiving feed signals from the three frequency bands respectively. I ₁ is for band 1, I ₂ is for band 2, and I ₃ is for band 3. A combing network combines input signals from different bands and outputs a combined feed signal to a feed port of an element. Thus, an input node of a combining network may also be understood as a feed port of an element, and consequently, the element is associated with a number of feed ports (i.e., input nodes of its associated combining network) . A combing network may be implemented in hardware, software, or a combination of hardware and software. A combining network may also be referred to as a combining circuit or a combing module. In the example of FIG. 3, instead of feeding each antenna element using signals of all the three frequency bands, a group of antenna elements are selected from the antenna array 310 to be fed for each frequency band. Multiple groups of antenna elements are selected for multiple frequency bands. The groups of antenna elements may be referred to as feeding groups. Each feeding group corresponds to a frequency band. Rules may be defined for selecting such group of antenna elements for each frequency band. In some embodiments, the following rules may be used to select feeding groups for different frequency bands. These rules may be applied for antenna arrays that have spacing determined based on the highest operating frequency of the antenna arrays.

Rule 1: For the highest operating frequency (f _h with a corresponding wavelength λ _h) of an antenna array, all elements are fed. That is, all elements of the antenna array are selected to be fed by signals in the highest frequency band. Thus, the corresponding feeding group includes all elements of the antenna array.

Rule 2: For an operating frequency (f with a corresponding wavelength λ) in a frequency band, whose wavelength is a multiple of λ _h (λ = k*λ _h, where k = 2, 3, ..., K) , a group of elements are selected from the antenna array and fed by signals in the frequency band. The corresponding feeding group includes a portion of the elements in the antenna array. The group of elements are selected such that spacing (i.e., a distance represented by d) between adjacent antenna elements to be fed in the group is equal to α *λ. That is, d = α *λ, where α = 0.2～1 as discussed above.

Rule 3: Minimize common elements among two or more groups selected when selecting a group according to Rule 2. A common element of two groups is referred to as an element that belongs to both the two groups.

Rule 4: Minimize coupling between groups when selecting a group according to Rule 2 and/or Rule 3. For example, elements less close to each other may have less coupling than elements that are closer to each other.

Taking the antenna array 310 as an illustrative example, three groups of elements (i.e., groups 1-3 for frequencies f1-f3, respectively) are selected for the three bands. According to Rule 1, for f1, i.e., the highest frequency, all the elements 312 (i.e., E ₁₁-E ₄₁) are fed by signals in band 1. Thus, the first group (group 1) includes all of the elements 312 in the antenna array 310, which are fed for band 1. For f2, because f2 = f1/2 and according to Rule 2, every the other element (in row and column) in the antenna array 310 may be selected and fed by signals in band 2. For example, E ₁₁, E ₁₃, E ₃₁ and E ₃₃ may be selected as the group 2 and fed by signals in band 2. The distance between E ₁₁ and E ₁₃, between E ₃₁ and E ₃₃, between E ₁₁ and E ₃₁, and between E ₁₃ and E ₃₁, are equal to d = 2* (α*λ ₁) = α *λ2. Other variations for the group 2 may also be possible, as long as the above rules are followed, e.g., the elements in the group 2 have a spacing of 2α*λ ₁. For example, E ₂₁, E ₂₃, E ₄₁ and E ₄₃ may be selected. In another example, E ₂₂, E ₂₄, E ₄₂ and E ₄₄ may be selected. For f3, because f3 = f1/4, according to Rule 2, every four elements (in row and column) in the antenna array 310 may be selected and fed by signals in band 3. For example, E ₁₁ may be selected into the group 3. However, if E ₁₁ is already selected into the group 2 (e.g., group 2 includes E ₁₁, E ₁₃, E ₃₁ and E ₃₃) , according to Rule 3, E ₁₁ may be avoided to be selected into group 3. In this case, E ₁₂ may be a candidate for group 3 because it is not selected into any other groups according to Rule 3. However, according to Rule 4, E ₂₁ (or other element in row 2 or 4) may be a better choice because coupling between the rows may be weaker than that between elements in the same row. According to Rule 4, group 3 may be selected from row 2 or row 4. Table 1 below shows an embodiment of feeding groups selected for feeding the antenna array 310.

Table 1

Table 2 shows another embodiment of feeding groups selected for the antenna array 310.

Table 2

FIG. 3 illustrates a feeding arrangement according to Table 2. Feed signals are represented by Sij in the ith frequency band for feeding feed port Pj, where i = 1, 2, 3, representing the 3 frequency bands, and j = 1, 2, ..., 16, representing the 16 feed ports. According to Table 2, E ₁₁ is fed for band 1 and band 3. Thus, a signal S ₁₁ in band 1 and a signal S ₃₁ in band 3 are input into input nodes I ₁ and I ₃ of combining network 322 for feeding feed port P1. E ₁₁ is not fed for band 2, and no signal in band 2 will be input into the combining network 1. A reactive load (RL) 341 is used to terminate the input node I2. That is, the input node I2 is connected to a ground through the RL 341. A RL may be a circuit that presents a capacitive or inductive load. E ₂₁, E ₂₃, E ₄₁ and E ₄₃ each is fed for both band 1 and band 2. Thus, a signal S ₁₂ in band 1 and a signal S ₂₂ in band 2 are input into input nodes I ₁ and I ₂ of combing network 2 for feeding P2. Similarly, S ₁₄ and S ₂₄ in respective band 1 and band 2 are input into combining network 4 for feeding P4, S ₁₉ and S ₂₉ in respective band 1 and band 2 are input into combining network 9 for feeding P9, and S ₁₁₁ and S ₂₁₁ in respective band 1 and band 2 are input into combining network 11 for feeding P11. Since E ₂₁, E ₂₃, E ₄₁ and E ₄₃ are not fed for band 3,

RLs

342, 343, 344 and 345 are used to terminal I ₂ of the respective combining

networks

324, 326, 328 and 330. The rest of the elements (i.e., E ₁₂, E ₁₃, E ₁₄, E ₂₂, E ₂₄, E ₃₁-E ₃₄, E ₄₂ and E ₄₄) are only fed for band 1. Thus a signal in band 1 is fed into each of the rest of elements. For example, a signal S ₁₁₆ in band 1 is input into I ₁ of combing network 16 for feeding P16. The other input nodes (I ₂, I ₃) of combining network 16 each is terminated using a RL 346 and 347, respectively. The RLs used for terminating input nodes of the same combining network or different combining networks may have the same value or different values. A value of a RL for a combining network may be determined such that a predetermined criterion is satisfied, e.g., return loss of the combining network satisfies a predetermined threshold. For example, the return loss should be greater than 10 dB, within the operation bandwidth required for a corresponding frequency band.

In some embodiments, patterns may be defined to specify what elements may be selected as members of a feeding group to be fed for a frequency band corresponding to an operating frequency. The patterns may be referred to as feeding patterns. Different feeding patterns may be configured or re-configured. Table 3 below provides an example of feeding patterns configured for operating frequencies in different bands. Each feeding pattern is associated with an operating frequency. In this example, pattern 0 is a default pattern for the highest operating frequency, where all elements of the antenna array are fed. Those of ordinary skill in the art would recognize that various feeding patterns may be configured which may be different than those shown in Table 3. Designing the feeding patterns may be based on the Rules 1-4 discussed above, or other rules that may be applicable. The patterns may be configured such that the antenna array may be fed to provide sufficient beam forming performance using feeding networks with reduced complexity.

Table 3

Table 3 shows that, for an operating frequency that is a fraction 1/n (n = 2, 3, ... ) of the highest operating frequency, that is, its corresponding wavelength is a multiple n of the wavelength corresponding to the highest operating frequency, every n elements may be selected to be fed generally. As an illustrative example, a 4x12 antenna array operates in 4 operating bands corresponding to operating frequencies f1-f4, f1 is the highest operating frequency, f2 = f1/3, f3 = f1/4, and f4 = f1/6. The 48 elements are represented by E _ij, where i = 1, 2, 3, 4, and j = 1, 2, ..., 12. Feeding groups corresponding to the four operating frequencies may be determined based on Table 3, and Table 4 below shows feeding groups determined in this example. Table 4 shows the feeding patterns applied for corresponding operating frequencies, and two possible options (i.e., Option 1 and Option 2) showing example elements selected for feeding. As can be seen from Table 4, Option 2 requires less elements to be fed than Option 1. This may be due to the finite size (4x12) of the example antenna array. Sufficient number of elements may be selected for feeding for each frequency band so that sufficient antenna gain may be obtained.

Table 4

For an operating frequency whose corresponding wavelength is not a multiple of the wavelength of the highest operating frequency, in one embodiment, the feeding patterns shown in Table 3 may also be used based on the value of the operating frequency falling in a particular frequency range. Table 5 below shows an example of frequency ranges and associated feeding patterns. For example, if an operating frequency is 0.41f _h, which falls in the range of 0.36 f _h ≤ f ≤ 0.55f _h, then pattern 1 in Table 3 may be used to select a feeding group to be fed for this operating frequency. In another example, if an operating frequency is 0.19f _h, which falls in the range of 0.18 f _h ≤ f ≤ 0.22f _h, then pattern 4 in Table 3 may be used. Those of ordinary skill in the art would recognize that the frequency range and the associated patterns may also vary. For example, pattern 0 may be used for frequencies in the range of 0.5f _h ≤ f ≤ f _h, and pattern 1 may be used for frequencies in the range of 0.25f _h ≤ f ≤ 0.5f _h, etc.

Frequency Range	Feeding Pattern ID
0.55 f _h ≤ f ≤ f _h	0
0.36 fh ≤ f ≤ 0.55fh	1
0.27 fh ≤ f ≤ 0.36fh	2
0.22 fh ≤ f ≤ 0.27fh	3
0.18 fh ≤ f ≤ 0.22fh	4
0.15 fh ≤ f ≤ 0.18fh	5
0.13 fh ≤ f ≤ 0.15fh	6
0.12 fh ≤ f ≤ 0.13fh	7
0.11 fh ≤ f ≤ 0.12fh	8

Table 5

In some embodiments, the frequency range and the associated patterns may be determined such that the following criterion is satisfied:

where the “Feeding Spacing” represents spacing between adjacent elements in a feeding group that are to be fed. For example, feeding spacing of group 2 in Table 2 is the distance between E ₂₁ and E ₂₃, between E ₄₁ and E ₄₃, or between E ₂₁ and E ₄₁. λ represents the wavelength of the corresponding operating frequency, and θ is the maximum beam scanning angle. Table 5 is an example using a θ of approximately 60 degrees.

FIG. 4 illustrates a diagram of another embodiment antenna system 400. The antenna system 400 includes an antenna array 410 and a feeding network 420. The antenna array 410 is a 4x4 array similar to the antenna array 310 in FIG. 3 and operable in UWB. The antenna array 410 includes a plurality of antenna elements 412, indicated by individual elements E ₁₁, E- ₁₂, …E ₄₄, that are arranged in 4

rows

413 and 4 columns 415. Each array element 412 of the antenna array 410 is represented by E _ij, where i = 1, 2, ..., n representing the ith row of the antenna array 410, and j = 1, 2, ..., m representing the jth column of the antenna array 410. E _ij represents the element in the ith row and the jth column of the antenna array 410. Each of the antenna elements 412 has a corresponding feed port for receiving feed signals. FIG. 4 illustrates 16 feed ports P1, P2, ..., P16 corresponding to the 16 antenna elements 412. The feeding network includes 16 combing networks 1-16 (i.e., 422-430) , each is connected to a respective feed port P1-P16, and provides a feeding signal to the respective feed port P1-P16. Each combining network has N input nodes I ₁-I _N for taking N feed signals in N frequency bands, respectively. N may be an integer that is greater than 1. The spacing of the antenna array 410 may be based on the wavelength at the highest operating frequency of the antenna array 410. For example, the spacing may be in a range of {0.2λ _h, λ _h} , where λ _h is the wavelength of the highest operating frequency f _h at which the antenna array 410 may operate. The antenna array 410 in this example is configured to operate in two frequency bands (i.e., band 1 and band 2) corresponding to two operating frequencies f1, f2, where f1 = f _h /4 and f2 = f _h/2.

Based on Table 3, the

feeding patterns

3 and 1 may be used to determine feeding groups to be fed for the two operating frequencies f1 and f2, respectively. For example, E ₂₁ may be selected according to feeding pattern 3 for f1, and E ₁₁, E ₁₃, E ₃₁ and E ₃₃ may be selected according to feeding pattern 1 for f2. In another example, E ₁₁ may be selected according to feeding pattern 3 for f1, and E ₂₁, E ₂₃, E ₄₁ and E ₄₃ may be selected according to feeding pattern 1 for f2, which case is shown in FIG. 4. In this case, E ₁₁ is only fed for band 1, and E ₂₁, E ₂₃, E ₄₁ and E ₄₃ are only fed for band 2. All the other elements will not be fed. As shown, a signal S ₁₁ in band 1 is input into the input node I ₁ of combining network 1 which is used to provide feed signals to E ₁₁. Other input nodes of combining network 1 are terminated by RLs because no feed signals in other bands are needed to feed E ₁₁. A signal S ₂₂ in band 2 is input into the input node I ₂ of combining network 2 which is to provide feed signals to E ₂₁. Other nodes, such as I ₁ and I _N, of combining network 2 are all terminated by RLs because no feed signals in other bands are needed to feed E ₂₁. A signal S ₂₄ in band 2 is input into the input node I ₂ of combining network 4 which is to provide feed signals to E ₄₁. Other nodes of combining network 4 are terminated by RLs. Similarly, each of combining

networks

9 and 11 providing respective feed signals to E ₂₃ and E ₄₃, receives a signal in band 2 at the input node I2 (not shown) , and has other input nodes terminated by RLs (not shown) . The rest of elements are not fed, and thus the corresponding combining networks (i.e., combining networks 3, 5-8, 10, 12-16) have all input nodes terminated by RLs. For example, as shown, the input nodes of combining

networks

3 and 16 are terminated by RLs. Some or all of the RLs used to terminate input nodes of the combining networks in FIG. 4 may have different values or same values.

The embodiments may be used for frequency division duplex (FDD) communications. FDD is a technique where different frequencies are used for transmission and receiving at the same time through the same antenna. To avoid interference between transmitted signals and received signals in the same frequency band for FDD communications, duplexers are required to separate the transmitted signals and received signals. This consequently complicates antenna systems. According to some embodiments, different antenna elements may be selected to be fed for transmitting and receiving signals in the same band. For example, a group of antenna elements may be selected, in a similar way as discussed above with respect to FIGs. 2-4, for transmission in a first frequency band, and an element that is not selected, either for transmission or receiving in any frequency band, may be selected for receiving signals in the first frequency band. In this case, duplexer may be avoided for separating transmission and receiving signals for FDD.

FIG. 5 shows an example for feeding different elements for transmission and receiving in the same frequency band. FIG. 5 illustrates a diagram of another embodiment antenna system 500 operable in UWB. The antenna system 500 includes an antenna array 510 and a feeding network 520. The antenna array 510 is a 4x4 array similar to the antenna array 310 in FIG. 3 or 410 in FIG. 4. The antenna array 510 includes a plurality of antenna elements, indicated by individual elements E ₁₁, E ₁₂, …E ₄₄, that are arranged in 4

rows

513 and 4 columns 515. Each array element is represented by E _ij, where i = 1, 2, ..., n representing the ith row of the antenna array 510, and j = 1, 2, ..., m representing the jth column of the antenna array 510. E _ij represents the element in the ith row and the jth column of the antenna array 510. Each of the antenna elements has a corresponding feed port for receiving feed signals, i.e., P1, P2, ..., P16. The feeding network 520 includes 16 combing networks 1-16, each of which is connected to a respective feed port P1-P16, and provides a feed signal to the respective feed port P1-P16. In this example, each combining network has 3 input nodes I ₁-I ₃ for taking 3 feed signals in 3 frequency bands, respectively. The combining networks may have any number of input nodes. The spacing of the antenna array 510 may be determined based on the wavelength of the highest operating frequency of the antenna array 510. For example, the spacing may be in a range of {0.2λ _h, λ _h} , where λ _h is the wavelength of the highest operating frequency f _h at which the antenna array 510 may operate.

The antenna array 510 in this example is configured to operate in band 1 for FDD communications, where the antenna array 510 operates at frequency f1 in band 1 for transmission, and at frequency f2 in band 1, which is different than f1, for receiving. In this example, both f1 and f2 fall in the range of 0.22 f _h ≤ f ≤ 0.27f _h. Feeding pattern 3 is used to select elements to be fed according to in Table 5. Thus, based on feeding pattern 3, only one element in the 4x4 antenna array 510 may need to be fed. For example, E ₁₁ (or E ₁₂, E ₃₁, or E ₄₄) may be selected to be fed for communication in band 1. However, instead of feeding one element for both transmission and receiving, two elements may be selected, with one fed for transmission and the other fed for receiving. For example, E ₁₁ is fed for transmission, and one of the rest elements may be selected to be fed for receiving. Rule 4 described above may be applied when selecting the two elements. For example, to reduce coupling between two elements selected for respective transmission and receiving, the two elements may be located in different rows, or have a maximal distance among the elements of the antenna array 510. Accordingly, in one example, E ₁₁-E ₁₄ may be good candidates to be selected for transmission, and E41-E ₄₄ may be good candidates to be selected for receiving, or vice versa. FIG. 5 illustrates an example where E ₁₁ is fed for transmission and E ₄₁ is fed for receiving for the 4x4 antenna array 510. As shown, combining network 1 is fed by a signal S ₁ in band 1, and other input nodes, i.e., I ₂ and I ₃, of combining network 1 are terminated by RLs. Combining network 4 is fed by a signal S ₂ in band 1, and other input nodes, i.e., I ₂ and I ₃, of combining network 4 are terminated by RLs. The rest of elements are not fed, and their associated combining networks are terminated by RLs. For example, input nodes I ₁-I ₃ of combining

networks

2, 3, and 16 are terminated by RLs, respectively.

It should be noted that, in a case where the antenna array 510 has a larger size, e.g., 8x4, and E ₁₁ is selected to be fed for transmission, according to the feeding pattern 3, another element E ₅₁ will also be selected for transmission. In this case, E ₄₁ may not be selected to be fed for receiving because it is very close to E ₅₁. Instead, one of E ₃₁-E ₃₄ may be fed for receiving. Similarly according to the feeding pattern 3, one of E ₇₁-E ₇₄ may also be fed for receiving. In one example, E ₁₁ and E ₅₁ are selected for transmission, and E ₃₁ and E ₇₁ are selected for receiving. In another example, E ₃₄ and E ₇₄ are selected for receiving. Corresponding combining networks may be arranged for feeding the selected elements similar to what is shown in FIG. 5.

FIG. 6 illustrates a diagram of another embodiment antenna system 600. The antenna system 600 includes an antenna array 610 and a feeding network 620. The antenna array 610 is similar to the

antenna array

310 or 410. As shown, the antenna array 610 includes a plurality of antenna elements, indicated by individual elements E ₁₁, E ₁₂, …E ₄₄, that are arranged in 4

rows

613 and 4 columns 615. Each array element is represented by E _ij, where i = 1, 2, ..., n representing the ith row of the antenna array 610, and j = 1, 2, ..., m representing the jth column of the antenna array 610. E _ij represents the element in the ith row and the jth column of the antenna array 610. The spacing of the antenna array 610 may be determined based on the wavelength of the highest operating frequency of the antenna array 610. For example, the spacing may be in a range of {0.2λ _h, λ _h} , where λ _h is the wavelength of the highest operating frequency f _h at which the antenna array 610 may operate. Each of the antenna elements has a corresponding feed port for receiving feed signals, P1, P2, ..., P16. The feeding network 620 includes 16 combing networks 1-16, each is connected to a respective feed port P1-P16, and provides a feeding signal to the respective feed port P1-P16. In this example, each combining network has 3 input nodes I ₁-I ₃ for taking feed signals in 3 frequency bands, respectively. The combining networks may have any number of input nodes.

Each input node of a combining network may be connected to a feed signal or a RL through a switch. As shown, for example, the input node I ₁ of combining network 1 may be connected to a feed signal S ₁₁ in band 1 or a RL through a switch 632, the input node I ₂ of combining network 1 may be connected to a feed signal S ₂₁ in band 2 or a RL through a switch 634, and the input node I ₃ of combining network 1 may be connected to a feed signal S ₃₁ in band 3 or a RL through a switch 636. Similarly, the input node I ₁ of combining network 16 may be connected to a feed signal S ₁₁₆ in band 1 or a RL through a switch 638, the input node I ₂ of combining network 16 may be connected to a feed signal S ₂₁₆ in band 2 or a RL through a switch 640, and the input node I ₃ of combining network 16 may be connected to a feed signal S ₃₁₆ in band 3 or a RL through a switch 642. Depending on the elements selected for feeding in different bands, these switches may be switched to connect an input node to a feed signal or a RL. For example, if E ₁₁ is selected to be fed for f1 and f3 as shown in FIG. 3, then the switch 632 may be switched to connect I ₁ of combining network 1 to S ₁₁, the switch 634 may switched to connect I ₂ of combining network 2 to the RL, and the switch 636 may be switched to connect I ₃ of combining network 1 to S ₃₁. In this way, the feeding network 620 becomes configurable, providing flexibility to generate different combined feed signals to feed an antenna element, or to terminate the antenna element using reactive loads.

For an antenna array configured to operate in UWB including multiple frequency bands, different groups of antenna elements may be selected to be fed for different frequency bands in accordance with predefined rules, e.g., Rules 1-4 as discussed above, or predefined patterns, e.g., Table 3 or Table 5 as discussed above. Selection of the different groups may be predetermined, e.g., by designers and/or service providers during a design stage. The antenna array is thereafter fed according to the predetermined selection of the different groups. In some embodiments, the antenna array may be configured with different feeding configurations. Each feeding configuration may specify one or more groups of antenna elements selected to be fed for respective frequency bands. Service providers may determine which feeding configurations may be used to feed the antenna array. Feeding networks, such as the feeding network 620 may be used to provide feed signals to the antenna array, where each input node of a combining network may be connected to a feed signal or a RL through a switch.

FIG. 7 illustrates a diagram of another embodiment antenna system 700. The antenna system 700 is able to provide dual polarization. The antenna system 700 includes a first antenna array and a second antenna array interleaved along a planar surface. The first antenna array includes a plurality of elements 702 represented by E ¹ _ij, where i = 1, 2, ..., n representing the ith row of the first antenna array, and j = 1, 2, ..., m representing the jth column of the first antenna array. E ¹ _ij represents the element in the ith row and the jth column of the first antenna array. The plurality of first elements 702 are indicated as being arranged in a generally “landscape” orientation in FIG. 7. The second antenna array is an array that is identical to the first antenna array but rotated (counter-clockwise or clockwise) by 90 degrees along the planar surface. The second antenna array includes a plurality of elements 712 represented by E ² _ij. The second elements 712 are indicated as being arranged in a generally “portrait” orientation in FIG. 7. First elements 702 and second elements 712 are arranged in alternating columns of elements, as shown in the drawing figure. However, other arrangements of first elements 702 and second elements 712 are encompassed by this disclosure. The first antenna array provides a first polarization, and the second antenna array provides a second polarization that is orthogonal to the first polarization. Each of the first antenna array and the second antenna array may be similar to the antenna array 310 (FIG. 3) , or 410 (FIG. 4) . Each of the first antenna array and the second antenna array operates in UWB including a plurality of frequency bands. Spacing of the first antenna array or the second antenna array is determined based on the wavelength of the highest operating frequency of the first antenna array and the second antenna array. For example, the spacing may be in a range of {0.2λ _h, λ _h} , where λ _h is the wavelength of the highest operating frequency f _h at which the first and the second antenna arrays may operate. Each of the first antenna array and the second antenna array may be fed by a feeding network as discussed with respect to any one of FIGs. 3-6.

FIG. 8 illustrates a flowchart of an embodiment method 800 for feeding an antenna array. The method 800 may be indicative of operations at an apparatus, such as a base station, that has one or more antennas for communications. As shown at step 802, the method 800 feeds a first antenna array of a device for wireless communications in an ultra-wide bandwidth, where a first group of antenna elements in the first antenna array is fed using signals in a first frequency band of a plurality of frequency bands. The first antenna array includes a plurality of antenna elements that are arranged in a number of rows in a planar surface, and the array of antenna elements has spacing determined based on a wavelength of a highest operating frequency of the first antenna array. The first group of antenna elements excludes a first antenna element in the first antenna array. In one example, the method 800 may feed the first antenna element by a signal in a frequency band of the plurality of frequency bands that is different than the first frequency band. I In another example, the method 800 may terminate a feed port of the first antenna element using a reactive load. In some embodiments, the method may also, at step 804, feed a second group of antenna elements in the first antenna array using signals in a second frequency band of the plurality of frequency bands. The second group of antenna elements is different than the first group of antenna elements, and at least one antenna element in the second group of antenna elements is fed without using a signal in the first frequency band.

FIG. 9 illustrates a flowchart of an embodiment method 900 for providing an antenna system. As shown, at step 902, the method 900 provides a first antenna array of a device for wireless communications in a bandwidth in which a ratio between a highest operating frequency and a lowest operating frequency exceeds 2: 1. The first antenna array includes a plurality of antenna elements that are arranged in a number of rows along a planar surface, and the plurality of antenna elements have spacing between adjacent elements determined in accordance with a wavelength of the highest operating frequency. At step 904, the method 900 feeds, using a feeding network, a first group of antenna elements of the plurality of antenna elements using signals in a first frequency band of a plurality of frequency bands. At step 906, the method 900 feeds, using the feeding network, a second group of antenna elements of the plurality of antenna elements using signals in a second frequency band of the plurality of frequency bands, without feeding at least one antenna element in the first group of antenna elements using a signal in the second frequency band.

FIG. 10 illustrates a block diagram of an embodiment processing system 1000 for performing methods described herein, which may be installed in a host device. As shown, the processing system 1000 includes a processor 1004, a memory 1006, and interfaces 1010-1014, which may (or may not) be arranged as shown in FIG. 10. The processor 1004 may be any component or collection of components adapted to perform computations and/or other processing related tasks, and the memory 1006 may be any component or collection of components adapted to store programming and/or instructions for execution by the processor 1004. In an embodiment, the memory 1006 includes a non-transitory computer readable medium. The

interfaces

1010, 1012, 1014 may be any component or collection of components that allow the processing system 1000 to communicate with other devices/components and/or a user. For example, one or more of the

interfaces

1010, 1012, 1014 may be adapted to communicate data, control, or management messages from the processor 1004 to applications installed on the host device and/or a remote device. As another example, one or more of the

interfaces

1010, 1012, 1014 may be adapted to allow a user or user device (e.g., personal computer (PC) , etc. ) to interact/communicate with the processing system 1000. The processing system 1000 may include additional components not depicted in FIG. 10, such as long term storage (e.g., non-volatile memory, etc. ) .

In some embodiments, the processing system 1000 is included in a network device that is accessing, or part otherwise of, a telecommunications network. In one example, the processing system 1000 is in a network-side device in a wireless or wireline telecommunications network, such as a base station, a relay station, a scheduler, a controller, a gateway, a router, an applications server, or any other device in the telecommunications network. In other embodiments, the processing system 1000 is in a user-side device accessing a wireless or wireline telecommunications network, such as a mobile station, a user equipment (UE) , a personal computer (PC) , a tablet, a wearable communications device (e.g., a smartwatch, etc. ) , or any other device adapted to access a telecommunications network.

In some embodiments, one or more of the

interfaces

1010, 1012, 1014 connects the processing system 1000 to a transceiver adapted to transmit and receive signaling over the telecommunications network. FIG. 11 illustrates a block diagram of a transceiver 1100 adapted to transmit and receive signaling over a telecommunications network. The transceiver 1100 may be installed in a host device. As shown, the transceiver 1100 comprises a network-side interface 1102, a coupler 1104, a transmitter 1106, a receiver 1108, a signal processor 1110, and a device-side interface 1112. The network-side interface 1102 may include any component or collection of components adapted to transmit or receive signaling over a wireless or wireline telecommunications network. The coupler 1104 may include any component or collection of components adapted to facilitate bi-directional communication over the network-side interface 1102. The transmitter 1106 may include any component or collection of components (e.g., up-converter, power amplifier, etc. ) adapted to convert a baseband signal into a modulated carrier signal suitable for transmission over the network-side interface 1102. The receiver 1108 may include any component or collection of components (e.g., down-converter, low noise amplifier, etc. ) adapted to convert a carrier signal received over the network-side interface 1102 into a baseband signal. The signal processor 1110 may include any component or collection of components adapted to convert a baseband signal into a data signal suitable for communication over the device-side interface (s) 1112, or vice-versa. The device-side interface (s) 1112 may include any component or collection of components adapted to communicate data-signals between the signal processor 1110 and components within the host device (e.g., the processing system 1000, local area network (LAN) ports, etc. ) .

The transceiver 1100 may transmit and receive signaling over any type of communications medium. In some embodiments, the transceiver 1100 transmits and receives signaling over a wireless medium. For example, the transceiver 1100 may be a wireless transceiver adapted to communicate in accordance with a wireless telecommunications protocol, such as a cellular protocol (e.g., long-term evolution (LTE) , etc. ) , a wireless local area network (WLAN) protocol (e.g., Wi-Fi, etc. ) , or any other type of wireless protocol (e.g., Bluetooth, near field communication (NFC) , etc. ) . In such embodiments, the network-side interface 1102 comprises one or more antenna/radiating elements. For example, the network-side interface 1102 may include a single antenna, multiple separate antennas, or a multi-antenna array configured for multi-layer communication, e.g., single input multiple output (SIMO) , multiple input single output (MISO) , multiple input multiple output (MIMO) , etc. The network-side interface 1102 may include an antenna array as discussed above with respect to FIGs. 3-7 which is fed as described above. In other embodiments, the transceiver 1100 transmits and receives signaling over a wireline medium, e.g., twisted-pair cable, coaxial cable, optical fiber, etc. Specific processing systems and/or transceivers may utilize all of the components shown, or only a subset of the components, and levels of integration may vary from device to device.

It should be appreciated that one or more steps of the embodiment methods provided herein may be performed by corresponding units or modules. For example, a signal may be transmitted by a transmitting unit or a transmitting module. A signal may be received by a receiving unit or a receiving module. A signal may be processed by a processing unit or a processing module. Other steps may be performed by a combining unit/module, a feeding unit/module, an inputting unit/module, a determining unit/module, a switching unit/module, a configuring unit/module, and/or a terminating unit/module. The respective units/modules may be hardware, software, or a combination thereof. For instance, one or more of the units/modules may be an integrated circuit, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs) .

While this disclosure has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the disclosure, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.

Claims

An apparatus comprising:

a first antenna array operable in a bandwidth in which a ratio between a highest designed operating frequency and a lowest designed operating frequency exceeds 2: 1, the first antenna array comprising a plurality of antenna elements that are arranged in a number of rows along a planar surface, the plurality of antenna elements having spacing between adjacent elements determined in accordance with a wavelength of the highest designed operating frequency;

a feeding network configured to feed a first group of antenna elements of the plurality of antenna elements using signals in a first frequency band of a plurality of frequency bands, and to feed a second group of antenna elements of the plurality of antenna elements using signals in a second frequency band of the plurality of frequency bands, without feeding at least one antenna element in the first group of antenna elements using a signal in the second frequency band.
The apparatus of claim 1, wherein a distance between two adjacent antenna elements in the first group of antenna elements satisfies a predetermined requirement based on a wavelength of the first frequency band and the highest operating frequency.
The apparatus as recited in any one of claims 1-2, wherein the feeding network comprises a plurality of combining networks providing feed signals to the respective plurality of antenna elements, each combining network comprising a plurality of input nodes receiving signals in the respective frequency bands, and an output node outputting a combined feed signal.
The apparatus of claim 3, wherein a combining network corresponding to the at least one antenna element in the first group of antenna element has an input node connected to a ground plane through a reactive load.
The apparatus as recited in any one of claims 1-4, wherein the spacing is in a range from 0.2λ to λ, wherein λ is the wavelength of the highest designed operating frequency.
The apparatus as recited in any one of claims 1-5, wherein the plurality of frequency bands comprises a frequency ranging from 700 MHz to 6 GHz.
The apparatus of claim 1, wherein at least one antenna element of the plurality of antenna elements is not fed.
The apparatus as recited in any one of claims 1-7, wherein the first group of antenna elements comprises all antenna elements of the first antenna array.
The apparatus as recited in any one of claims 1-7, wherein the first group of antenna elements comprises a portion of antenna elements of the first antenna array.
The apparatus of claim 9, wherein an antenna element in the first group of antenna elements is located in a row that is different than the second group of antenna elements.
The apparatus as recited in any one of claims 1-7 and 9-10, wherein each of the first group of antenna elements is different than the second group of antenna elements.
The apparatus as recited in any one of claims 1-11, wherein the second group of antenna elements comprises two antenna elements in a same row, the two antenna elements being separated by at least a third antenna element in the same row.
The apparatus as recited in any one of claims 1-12, wherein the second group of antenna elements comprises antenna elements arranged across the number of rows according to a predetermined pattern.
The apparatus as recited in any one of claims 1-13, wherein the apparatus is a base station.
The apparatus as recited in any one of claims 1-14, wherein the second group of antenna elements is fed for transmission by the apparatus according to frequency division duplex (FDD) , and a first antenna element of the first antenna array not belonging to the second group of antenna elements is fed by a signal in the second frequency band for reception by the apparatus according to the FDD.
The apparatus as recited in any one of claims 1-15, further comprising:

a second antenna array that is identical to the first antenna array, the second antenna array being rotated by 90 degrees along the planar surface and interleaved with the first antenna array along the planar surface, the first antenna array and the second antenna array being configured to operate to provide dual polarization.
The apparatus as recited in any one of claims 1-16, wherein the first antenna array is a tightly coupled array (TCA) .
The apparatus as recited in any one of claims 1-17, wherein the first antenna array is a tapered slot antenna (TSA) array.
A method comprising:

providing a first antenna array of a device for wireless communications in a bandwidth in which a ratio between a highest designed operating frequency and a lowest designed operating frequency exceeds 2: 1, the first antenna array comprising a plurality of antenna elements that are arranged in a number of rows along a planar surface, and the plurality of antenna elements having spacing between adjacent elements determined in accordance with a wavelength of the highest designed operating frequency;

feeding, using a feeding network, a first group of antenna elements of the plurality of antenna elements using signals in a first frequency band of a plurality of frequency bands; and

feeding, using the feeding network, a second group of antenna elements of the plurality of antenna elements using signals in a second frequency band of the plurality of frequency bands, without feeding at least one antenna element in the first group of antenna elements using a signal in the second frequency band.
The method of claim 19, wherein at least one antenna element of the plurality of antenna elements is not fed.
The method of claim 19, further comprising:

connecting a feed port of an antenna element of the plurality of antenna elements to a ground plane through a reactive load.
The method of claim 21, further comprising:

configuring the reactive load according to a predetermined criterion.
The method as recited in any one of claims 19-22, wherein the spacing is in a range from 0.2λ to λ, wherein λ is the wavelength of the highest designed operating frequency.
The method as recited in any one of claims 19-23, wherein the plurality of frequency bands comprises a frequency ranging from 700 MHz to 6 GHz.
The method as recited in any one of claims 19-24, wherein the first group of antenna elements comprises all antenna elements of the first antenna array.
The method as recited in any one of claims 19-24, wherein the first group of antenna elements comprises a portion of antenna elements of the first antenna array.
The method of claim 26, wherein an antenna element in the first group of antenna elements is located in a row that is different than the second group of antenna elements.
The method as recited in any one of claims 19-24 and 27, wherein each of the first group of antenna elements is different than the second group of antenna elements.
The method as recited in any one of claims 19-28, wherein the first group of antenna elements is determined according to a predetermined pattern.
The method as recited in any one of claims 19-29, wherein the device is a base station.
The method as recited in any one of claims 19-30, wherein the second group of antenna elements is fed for transmission by the apparatus according to frequency division duplex (FDD) , and a first antenna element of the first antenna array not belonging to the second group of antenna elements is fed by a signal in the second frequency band for reception by the apparatus according to the FDD.
The method as recited in any one of claims 19-31, further comprising:

feeding a second antenna array that is identical to the first antenna array, the second antenna array being rotated by 90 degrees along the planar surface and interleaved with the first antenna array along the planar surface, the first antenna array and the second antenna array being configured to operate to provide dual polarization.
The method as recited in any one of claims 19-32, wherein the first antenna array is a tightly coupled array (TCA) .
The method as recited in any one of claims 19-32, wherein the first antenna array is a tapered slot antenna (TSA) array.