WO2018073650A1

WO2018073650A1 - Polygonal loop antenna, communication device and method for manufacturing antenna

Info

Publication number: WO2018073650A1
Application number: PCT/IB2017/001470
Authority: WO
Inventors: Fei Gao; Jinxing LU; Gang Shen
Original assignee: Alcatel Lucent
Priority date: 2016-10-20
Filing date: 2017-10-18
Publication date: 2018-04-26
Also published as: CN107968264B; CN107968264A

Abstract

Embodiments of the present disclosure relate to a polygonal loop antenna, a communication device and a method for manufacturing an antenna. For example, a polygonal loop antenna comprises: a radiation element, including a plurality of radiation units, each of the radiation units forming one side of the antenna; a plurality of capacitive elements, an even number of the capacitive elements being placed on each side of the antenna; and a plurality of feeding units, each of the feeding units is placed between two adjacent capacitive elements of the capacitive elements on each side of the antenna. Further, there is disclosed a corresponding communication device and method for manufacturing an antenna.

Description

POLYGONAL LOOP ANTENNA, COMMUNICATION DEVICE AND METHOD FOR MANUFACTURING ANTENNA

FIELD

[0001] Embodiments of the present disclosure generally relate to communication technologies, and more particularly, to a polygonal loop antenna, a corresponding communication device and a method for manufacturing an antenna.

BACKGROUND

[0002] The fourth generation (4G) and fifth generation (5G) standards aim to provide a higher speed for mobile communication. Multiple-input-multiple-output (MIMO) technology has been used in 4G Long-Term Evolution (LTE) wireless communication to provide a large channel capacity. In MIMO systems, antenna diversity such as widely used polarization diversity is used to enhance the performance of wireless communication systems. In addition to polarization diversity, pattern diversity technology is further used in MIMO systems to increase the system capacity. Pattern diversity technology can take advantage of the incoherence of the rays with totally different angle of arrival. Compared with an omnidirectional antenna, a directional antenna such as an antenna with a conical radiation pattern can significantly improve the system capacity.

[0003] However, the effects of pattern diversity on the capacity improvement are closely related to a radio environment. In a bad radio environment, for example, when the signal-to-noise ratio (SNR) is low, the effects of directional antennas on the capacity improvement are not so obvious. At present a reconfigurable antenna (RA) with pattern diversity has drawn wide attention in standardization work for 5G systems. However, no RA that is applicable to MIMO systems has been designed so far. With respect to an indoor positioning scenario, a pattern RA has been proposed to increase the accuracy of a positioning system. RAs used in an RSS-based positioning system are always large in size and difficult to be integrated in a MIMO antenna array.

SUMMARY

[0004] Generally, embodiments of the present disclosure propose a polygonal loop antenna, a corresponding communication device and a method for manufacturing an antenna.

[0005] In a first aspect, embodiments of the present disclosure provide a polygonal loop antenna. The antenna comprises: a radiation element, including a plurality of radiation units, each of the radiation units forming one side of the antenna; a plurality of capacitive elements, an even number of the capacitive elements being placed on each side of the antenna; and a plurality of feeding units, one of the plurality feeding units being placed between two adjacent capacitive elements of the capacitive elements on each side of the antenna.

[0006] In a second aspect, embodiments of the present disclosure provide a communication device, comprising at least one antenna according to the first aspect.

[0007] In a third aspect, embodiments of the present disclosure provide a method for manufacturing an antenna according to the first aspect. [0008] As is to be understood from the following description, according to embodiments of the present disclosure, there is provided a polygonal loop antenna structure. Each side of the antenna is formed by one radiation unit, an even number of capacitive elements is placed on the side, and one feeding unit is placed between two adjacent capacitive elements. Compared with a conventional antenna, the polygonal loop antenna according to embodiments of the present disclosure is thinner and smaller in size but has a relatively wide operating bandwidth and can produce more radiation states. Furthermore, a feeding network of the polygonal loop antenna is simple and easy to manufacture.

[0009] It should be appreciated that contents as described in the SUMMARY portion are not intended to limit key or important features of embodiments of the present disclosure or used to limit the scope of the present disclosure. Other features of the present disclosure will become easier to understand from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other features, advantages and aspects of various embodiments of the present disclosure will become apparent from the following detailed illustration with reference to the accompanying drawings in which the same or similar reference numerals denote the same or similar elements, wherein:

[0011] Fig. 1 shows a perspective view of a shared aperture antenna with two radiation states;

[0012] Figs. 2(a), 2(b) and 2(c) show top view, side view and bottom view of such an antenna respectively;

[0013] Fig. 3 shows a perspective view of a square loop antenna (SLA) with the hybrid high impedance surface (HHIS) loaded;

[0014] Fig. 4 shows a perspective view of a capacitively coupled SLA;

[0015] Figs. 5(a) and 5(b) show perspective view and top view of a polygonal loop antenna according to some other embodiments of the present disclosure; [0016] Fig. 6 shows a reflection coefficient curve of an antenna according to the present disclosure;

[0017] Fig. 7 shows a three-dimensional radiation pattern of an antenna according to some embodiments of the present disclosure;

[0018] Figs. 8(a) and 8(b) show a two-dimensional radiation pattern of an antenna according to some embodiments of the present disclosure;

[0019] Fig. 9 shows co-polarized component and cross-polarized component of a radiation pattern of an antenna in the elevation plane according to some embodiments of the present disclosure;

[0020] Figs. 10(a) and 10(b) show 3D radiation patterns of an antenna with respect to four antenna configurations according to some embodiments of the present disclosure; and

[0021] Fig. 11 shows a block diagram of a communication device according to some embodiments of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

[0022] Embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Although some embodiments of the present disclosure have been illustrated in the accompanying drawings, the present disclosure can be implemented in various manners, and should not be construed to be limited to embodiments disclosed herein. On the contrary, those embodiments are provided for the thorough and complete understanding of the present disclosure. It should be understood that the accompanying drawings and embodiments of the present disclosure are merely for the illustration purpose, rather than limiting the protection scope of the present disclosure.

[0023] The term "communication device" used herein refers to a device capable of receiving and transmitting radio signals in a wireless communication network. Examples of the communication device include a network device and a terminal device.

[0024] The term "network device" used herein refers to other entity or node with specific function in a base station or communication network. The "base station (BS)" may represent a node B (NodeB or NB), an Evolved Node B (eNodeB or eNB), a remote radio unit (RRU), a radio-frequency head (RH), a remote radio head (RRH), a repeater, or a low power node such as a Picocell, a Femto cell and the like. In the context of the present disclosure, the terms "network device" and "base station" may be used interchangeably, and generally, the eNB is taken as an example of the network device, for the sake of discussion.

[0025] The term "terminal device" or "user equipment (UE)" used herein refers to any terminal device that can perform wireless communication with the base station or one another. As an example, the terminal device may include a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), a mobile station (MS) or an access terminal (AT), and the above on-board devices. In the context of the present disclosure, the terms "terminal device" and "user equipment" may be used interchangeably for the sake of discussion.

[0026] The terms "comprise", "include" and their variants used here are to be read as open terms that mean "include, but is not limited to". The term "based on" is to be read as "based at least in part on". The term "one embodiment" is to be read as "at least one embodiment"; the term "another embodiment" is to be read as "at least one other embodiment". Definitions of other terms will be presented in description below.

[0027] As described above, a reconfigurable antenna (RA) with pattern diversity has drawn wide attention in standardization work for 5G systems. However, conventional antenna solutions have disadvantages such as low gain, narrow bandwidth, complex large three-dimensional (3D) structure and the like, which would limit the performance of MIMO antenna arrays. MEVIO antennas require the RA to be small enough as a basic element.

[0028] In addition, with respect to the indoor positioning scenario, a pattern RA has been proposed to increase the accuracy of a positioning system using the received signal strength (RSS). Compared to methods of time of arrival (TOA), time difference of arrival (TDOA), and angle of arrival (AOA), an RSS-based approach is more viable. On the one hand, the approach can exploit the existing wireless infrastructures and thus reduce capital expenditures (CAPEX). On the other hand, all current standard commodity radio technologies, such as Wi-Fi, ZigBee, active radio frequency identification (RFID), Bluetooth and the like, provide RSS measurements, and consequently the same algorithms on RSS measurements can be applied across different system platforms. However, complex multipath effects exist in unpredictable indoor environments, which include shadowing (such as, blocking a signal), reflection (such as, radio waves bouncing off an object), diffraction (such as, radio waves spreading in response to obstacles), and refraction (such as, radio waves bending as they pass through different mediums) and the like. The RSS measurements will be attenuated in unpredictable ways due to these effects. The utilization of the pattern RA may improve the accuracy of the RSS-based positioning system. Nevertheless, as discussed above, RAs used in the RSS-based positioning system are usually large in size and difficult to be integrated in MIMO antenna arrays. In this case, there is a need to design an efficient antenna layout in small size and thickness but with large bandwidth, so as to be applied to MIMO systems.

[0029] There has been proposed a method for increasing the operating bandwidth without increasing the size of an antenna. Figs. 1, 2(a), 2(b) and 2(c) show perspective view, top view, side view and bottom view of an exemplary antenna 100 designed using this method, respectively. As shown in Fig. 1, the antenna 100 includes a circular radiation patch 110, a grounded substrate 120 and a feeding patch 130. In this example, the substrate 120 has a thickness H of 3.7 millimeters, and may select a Rogers RT/duroid® 5880 (tm) substrate. The substrate 120 has a permittivity of 2.2 and a dielectric loss tangent of 0.0009. The feeding patch 130 is connected with a feeding probe 140 and has a distance of hi to the radiation patch 110. Five shoring posts 150-1 to 150-5 (collectively referred to as shoring posts 150) are placed around the feeding patch 130 and the feeding probe 140.

[0030] As shown in Fig. 2(c), the shoring post 150-1 is connected to the ground via two coupling capacitors 210. The shoring posts 150-2 to 150-5 may be connected to the ground through PIN diodes 220 or may not be connected to the ground. A direct current (DC) control signal may be fed via the shoring post 150-1 after passing through an RF choke 230, as shown in Fig. 2(b). Accordingly, a DC path is formed from the shoring post 150-1 through the radiation patch 110 to the rest shoring posts 150-2 to 150-5. Thus, a broadside radiation pattern and a conical radiation pattern can be obtained from such an antenna layout.

[0031] In addition, a square loop antenna (SLA) has been proposed for beam adaptive application. Typically, an SLA has four feeding points. When one feeding point is excited at a time, the beam may be steered in four different space quadrants, and thus four radiation states may be produced. However, this antenna has three major drawbacks that restrict its implementation: (a) it has a large thickness of a quarter wavelength; (b) it has a limited bandwidth; (c) it has a radiation pattern with strong sidelobes.

[0032] In view of these drawbacks, several solutions have been proposed. One method is to load the hybrid high impedance surface (HHIS) to SLA. Fig. 3 shows a perspective view of an exemplary HHIS-loaded SLA 300. As shown in this figure, the SLA 300 has feeding points 305, 310, 315 and 320 disposed on four sides respectively. This method of loading HHIS can significantly reduce the thickness of the antenna. For example, the thickness of the antenna is reduced to ^ ^{713 6} at the frequency of 4.7 GHz. However, the implementation of this design is complicated. For example, many apertures have to be punched, which wastes manpower and material costs, as shown in Fig. 3. Moreover, the antenna is still large in size.

[0033] Fig. 4 shows another SLA 400, which employs capacitively coupling. As shown in this figure, each of the four sides of the SLA 400 has a length of 1_1; and the substrate has a length of L. Feeds 405, 410, 415 and 420 are disposed on the four sides respectively. At each feed 405, 410, 415 or 420, there is provided a rectangular metal patch that is l_pi wide and Wpi thick. A Wi wide gap is formed between each metal patch and the antenna, so that capacitively coupling is effected. Furthermore, a g_\ wide opening is provided on each side of the SLA 400. Such a layout can significantly reduce the thickness of the antenna and thus is easy to implement. However, in the antenna layout, single resonance is formed between each metal patch and the corresponding antenna opening, which leads to some losses in operating bandwidth.

[0034] To solve these and other potential problems, embodiments of the present disclosure provide a polygonal loop antenna, each side of which is formed by a radiation unit. An even number of capacitive elements are placed on each side of the antenna, and a feeding unit is placed between two adjacent capacitive elements. Compared with a traditional antenna, the polygonal loop antenna according to embodiments of the present disclosure has a smaller size and thickness but a larger bandwidth and can form more adaptive radiation beams. [0035] The principles and specific embodiments of the present disclosure are illustrated in detail hereinafter with reference to Figs. 5(a) and 5(b), which show a perspective view and a top view of an exemplary polygonal loop antenna 500 according to some embodiments of the present disclosure respectively.

[0036] In this example, the antenna 500 is implemented as a square loop antenna, namely SLA. However, it should be understood this is merely for the illustration purpose. In other embodiments, the antenna 500 may have any other appropriate number of sides. For example, the antenna 500 may be implemented as a triangular loop, a pentagonal loop and the like.

[0037] As shown in these figures, the antenna 500 includes a radiation element 505 that includes four radiation units 510-1, 510-2, 510-3 and 510-4 (collectively referred to as radiation units 510). The antenna 500 may radiate a received feeding signal via the radiation element 505, which will be further described later. In this example, each radiation unit 510 is implemented as a metal conducting strip for a corresponding radiation function. As shown in Fig. 5(b), the metal conducting strip has an exemplary length l_a of 40 mm and an exemplary width w_a of 1.6 mm. Usually, the resonant frequency of the SLA is inversely proportional to its average circumferential length, so the average perimeter of the antenna 500 in this example is ( ^4x(^{/« "} "^«) ) = 153.6 mm, producing a resonant frequency about 3.5 GHz. Therefore, requirements of the LTE band 3.4-3.6GHz can be satisfied.

[0038] The antenna 500 further includes a plurality of capacitive elements 520- 1 to 520-8 (collectively referred to as capacitive elements 520). In this example, two capacitive elements are placed on each side. It should be understood this is merely exemplary and not limiting. Any appropriate even number of capacitive elements may be placed on each side of the antenna. For example, in some embodiments, four capacitive elements 520 may be placed on each side.

[0039] According to an embodiment of the present disclosure, the capacitive element 520 may be implemented as any appropriate capacitive element that is currently available or to be developed later. In this example, as shown in Fig. 5(b), the capacitive element 520 is an interdigital capacitor, where has a length / of 4mm, a width vty of0.3 mm and a gap gf of 0.2 mm.

[0040] The capacitive element 520 should be placed on each side of the antenna 500 without reducing the radiation efficiency. In this embodiment, the capacitive element 520 shoul be close to a feeding port as much as possible. A loaded capacitive value and the location of the antenna may be adjusted to further reduce the thickness of the antenna, and meanwhile, the operating bandwidth or radiation efficiency of the antenna will be affected. In some embodiments, the capacitive elements 520- 1 and 520-2 are embedded in a corresponding metal conducting strip (that is, the radiation unit 510- 1). [0041] According to an embodiment of the present disclosure, the antenna 500 further includes a plurality of feeding units 530- 1, 530-2, 530-3 and 530-4 (collectively referred to as feeding units 530). On each side of the antenna 500, a feeding unit 530 is placed between two adjacent capacitive elements 520. In this example, each feeding unit 530 includes a feeding probe 540-1, 540-2 540-3 or 540-4 respectively (collectively referred to as feeding probes 540). The size of the feeding probe 540 may be designed according to actual demands. In this example, the feeding probe 540 has a diameter of 1.3 mm.

[0042] As shown in the figure, the feeding probes 540 touch the radiation units 510 at corresponding feeding points 550-1, 550-2, 550-3 and 550-4 (collectively referred to as feeding points 550). The feeding probe 540 is used for receiving a feeding signal. Subsequently, the feeding signal is radiated by the radiation element 505, as described above.

[0043] Like a conventional SLA, a plurality of tilted beams can be controlled by feeding one feeding probe (for example, the feeding probe 540-1) at a time while remaining other feeding probes (for example, the feeding probes 540-2, 540-3 and 540-4) open. Therefore, a plurality of radiation states may be formed. The produced tilted beam is directed oppositely to the corresponding feeding point. In this way, the antenna 500 can produce a plurality of tilted beams, each of which may be controlled by selecting a corresponding feeding port.

[0044] To further enhance the performance of the antenna, in some embodiments, the capacitive elements 520 may be placed symmetrically around the corresponding feeding point 550. A distance between the capacitive elements 520 may be designed according to actual demands. In this example, two adjacent capacitive elements 520 have a distance of 4 mm.

[0045] The antenna 500 further includes a hexagonal substrate 560. In this example, the substrate 560 uses a three-layered laminated material, for example, may be select as a Taconic RF-60 (tm) laminated shelf. The substrate 560 has a total thickness of 5.4 mm and a side length Lof 80 mm. As shown in the figure, in this example, an angle of intersection between two adjacent radiation units 510 is opposite to one side of the substrate 560, which further reduces the size of the antenna. It should be understood the substrate may be designed into any appropriate shape according to actual demands. The scope of the present disclosure is not limited in this regard.

[0046] According to an embodiment of the present disclosure, there is provided a method for reducing the size and thickness of a conventional antenna while increasing the operating bandwidth thereof. The antenna as proposed may be a shared aperture reconfigurable antenna which is much smaller than the reconfigurable antenna based on selecting each sub-element. The thickness is approximately ⁰⁰⁶³^^o at 3.5 GHz, which is thinner than the conventional antenna 300 (for example, 0.074λο) shown in Fig. 3 and is slightly thicker than the antenna (0.045λο) shown in Fig. 4 but has 3 times bandwidth of the structure shown in Fig. 4. The size and thickness are directly related to the cost and compactness of the antenna. The reduction in size and thickness makes it possible for a MIMO antenna array to use the RA while keeping a compact structure for the whole system. The antenna can be applied to MIMO and positioning in 5G systems by virtue its small size and thickness, wide bandwidth as well as high reconfigurability, .

[0047] With reference to Figs. 6 to 10, illustration is presented below regarding the radio-frequency (RF) performance of a polygonal loop antenna according to an embodiment of the present disclosure. The illustrated RF performance is the RF performance when the feeding point 530-1 of the antenna is excited, which is analyzed and simulated on the basis of Ansoft HFSS.

[0048] Fig. 6 shows a reflection coefficient curve 600 of the antenna 500. The curve 600 is obtained using a generator impedance of 50 Ω . As shown in this figure, the reflection coefficient meets a criterion below -10 dB within a frequency band range from 3.35 GHzto 3.90 GHz. In particular, the reflection coefficient is below -15 dB within a frequency band range from 3.4 GHzto 3.79 GHz. The respective bandwidths of the two frequency bands account for 15.2% and 10.8% of the entire frequency band. The operating bandwidth of the antenna 500 increases significantly compared with the conventional antenna. In addition, the introduction of the interdigital capacitor leads to two adjacent resonant frequency points and brings an improved operating bandwidth with a reduced thickness of the antenna.

[0049] Figs. 7, 8(a) and 8(b) show a radiation pattern of the antenna 500 respectively, among which Fig. 7 shows a 3D radiation pattern 700 and Figs. 8(a) and 8(b) show two-dimensional (2D) radiation patterns 810 and 820 of the antenna 500 respectively. The patterns 700 and 800 are tested at 3.5 GHz that is the center frequency point. [0050] As shown in Fig. 7, the antenna 500 generates a tilted radiation pattern in the quadrant. When the feeding point 530-1 is excited while other feeding points 530-2, 530-3 and 530-4 remain open circuited, the radiation direction of the antenna 500 is opposite to the excited feeding points 530-1. The 2D pattern 810 shown in Fig. 8(a) is obtained by cutting the 3D pattern 700 along <* = ¹⁸⁰ . As shown in this figure, the peak point is directed to ^{61 = 43 >}^ = ¹⁸⁰ . The antenna 500 has a maximum realized gain of 7.7 dBi in the direction of the maximum radiated field.

[0051] Fig. 9 shows a co-polarized component 910 and a cross-polarized component 920 of the radiation pattern of the antenna 500 in an elevation plane. Due to the current flow in the linear direction, the main lobes are linearly polarized in the ^E" direction. Because of that, the cross-polarized component has a very low magnitude, and thus is invisible in the elevation cut of the pattern. The cross-polarized component is displayed if the pattern is cut along the azimuth. The cross-polarized component is lldB lower than the co-polarized component, which is better than the conventional antenna. In addition, there is no cross-polarized sidelobe in the direction of the co-polarized main lobe. The main beams have a half-power azimuth beam width of about 60°. Where capacitive elements are symmetrically loaded on two sides of each of the feeding points 530-1 to 530-4 in the antenna 500, the radiation patterns obtained by exciting the feeding points 530-2, 530-3 and 530-4 are expected to be the same as the pattern obtained by exciting one feeding point 530-1.

[0052] Figs. 10(a) to 10(d) show 3D radiation patterns

with respect to four antenna configurations. In the configuration shown in Fig. 10(a), ( _max is 42^° and <Z>_max is 180^° <*- ^{= 180°} ; in Fig. 10(b), 6>_max is 42^° and <Z>_max is 270^° ; in Fig. 10(c), 6>_max is 42^° and <P_max is 360^° ; in Fig. 10(d), ( _max is 42^° and <P_max is 90^° . Hence, each of the four configurations radiates a tilted beam in a different space quadrant, thus realizing a pattern reconfigurable antenna.

[0053] Fig. 11 shows a block diagram of a communication device 1100 which is applicable to implement the embodiments of the present disclosure. As shown in this figure, the communication device 1100 includes a controller 1110. The controller 1110 controls operations and functions of the communication device 1100. For example, in some embodiments, the controller 1110 may execute various operations by means of instructions 1130 stored in a memory 1120 coupled to the controller 1110. The memory 1120 may be of any appropriate type that is applicable to a local technical environment, and may be implemented using any appropriate data storage techniques, including without limitation to, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems. Though only one memory unit is shown in Fig. 11, there may be a plurality of physically different memory units in the device 1100.

[0054] The controller 1110 may be of any appropriate type that is applicable to a local technical environment, and may include without limitation to, a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), as well as one or more processors in a processor based multi-core processor architecture. The device 1100 may also comprise multiple controllers 1110. The controller 1110 is coupled to a transceiver 1140 that may receive and transmit radio signals by means of one or more antennas 1150 and/or other component. All features described with reference to Figs. 5 and 10 are applicable to the antenna 1150, which is ignored here. [0055] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. [0056] For example, embodiments of the present disclosure can be described in the general context of machine-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0057] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0058] In the context of this disclosure, a machine readable medium may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but is not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0059] Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

[0060] Although the subject matter has been described in a language that is specific to structural features and/or method actions, it is to be understood the subject matter defined in the appended claims is not limited to the specific features or actions described above. On the contrary, the above-described specific features and actions are disclosed as an example of implementing the claims.

Claims

I/We Claim:

1. A polygonal loop antenna, comprising:

a radiation element including a plurality of radiation units, each of the radiation units forming one side of the antenna;

a plurality of capacitive elements, an even number of the capacitive elements being placed on each side of the antenna; and

a plurality of feeding units, one of the plurality feeding units being placed between two adjacent capacitive elements of the capacitive elements on each side of the antenna.

2. The antenna according to claim 1, wherein the feeding unit comprises:

a feeding probe for receiving a feeding signal and touching the radiation unit at a feeding point.

3. The antenna according to claim 2, wherein the two adjacent capacitive elements are symmetrically placed on two sides of the feeding point.

4. The antenna according to claim 1, further comprising:

a polygonal substrate, an angle of intersection between two adjacent radiation units of the radiation units being opposite to one side of the substrate.

5. The antenna according to claim 1, wherein the radiation units include a metal conducting strip.

6. The antenna according to claim 5, wherein one of the capacitive elements is embedded in the metal conducting strip.

7. The antenna according to Claim 1, wherein the capacitive elements include an interdigital capacitor.

8. A communication device, comprising at least one antenna according to any one of claims 1 to 7.

9. A method for manufacturing an antenna according to any one of claims 1 to 7.