WO2017058177A1

WO2017058177A1 - Coupled slot antennas

Info

Publication number: WO2017058177A1
Application number: PCT/US2015/052962
Authority: WO
Inventors: Sung Oh; Philip Wright; Ken MACLEAN; Owen P COLUMBUS
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2015-09-29
Filing date: 2015-09-29
Publication date: 2017-04-06
Also published as: TW201712947A

Abstract

Examples described herein include examples of an antenna having a planar conductive body comprising an edge and a slot to form the coupled slot antenna comprising a first antenna arm coupled to the edge of the conductive body, and a second antenna arm coupled to the edge of the conductive body and separated from the first antenna arm by a coupling gap

Description

COUPLED SLOT ANTENNAS

BACKGROUND

[0001] Many types of mobile computing devices use wireless

communication protocols to transmit and receive wireless electronic signals corresponding to voice and data. The transmission or reception of various wireless electronic signals involve the use of various corresponding types of antennas. The directivity, efficiency, and frequency ranges of such antennas are often constrained by the limitations placed on the size, volume, and dimensions of the device in which the antennas are implemented. The trend for smaller and thinner mobile computing devices, such as tablets, smart phones, laptops, and the like, introduce additional complexity in antenna design for use in such devices.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 illustrates an example integrated slot antenna.

[0003] FIG.2 depicts a detailed view of an example integrated slot antenna.

[0004] FIG. 3 illustrates dimensional details of an example integrated slot antenna.

[0005] FIG.4 depicts a circuit equivalency of an integrated slot antenna.

[0006] FIG. 5 illustrates example frequency response of an integrated slot antenna.

[0007] FIG.6 illustrates an example mobile computing device equipped with an integrated slot antenna.

[0008] FIG. 7 illustrates a flowchart of an example method of forming an integrated slot antenna

DETAILED DESCRIPTION

[0009] The form factor of mobile computing devices, such as smart phones and tablet computers, are moving towards thinner housings with larger displays and smaller bezels. Such diminutive form factors result in smaller volumes in the housing available for high performance antennas used for electronic wireless communication. Fundamental laws of physics dictate the antenna design for a particular frequency bandwidth for use in a given volume. Implementations of the coupled slot antenna structures of the present disclosure allow for thin profile mobile computing devices while increasing the radiation performance of the antenna to address the gain-bandwidth limitations of physically small antennas. In particular, the present disclosure can address the volume constraints and increase antenna performance by using existing metal frames or decorative metal structures of the mobile computing device as antenna elements. Because examples of the present disclosure can be implemented in existing metal frames or decorative metal structures, increases in engineering costs and bill of material costs can be avoided.

[0010] Example implementations of the present disclosure include a coupled slot antenna structure that can generate two distinctive, but complimentary, antenna modes. As described herein, the two antenna modes can include a slot mode and a coupled monopole mode. The term "slot mode", as used herein, can refer to scenarios or modes of operation in which radiation is excited or detected in the slot. The term "coupled monopole mode", as used herein, can refer to scenarios or modes of operation in which radiation is excited or detected in the coupled arm antenna by a coupling effect to function as an open resonator for radio waves, oscillating with standing waves of voltage and current along its length. By using the two antenna modes, examples of the present disclosure can result in dual wideband resonances for wireless data communication.

[0011] FIG. 1 depicts an overview and a detailed view of a schematic diagram of a coupled slot antenna structure according to various

implementations of the present disclosure. As shown, the coupled slot antenna structure 130 can be disposed on the edge of a metal, or otherwise conductive, structural element 110. In the particular example shown, the conductive structural element 110 can be implemented as a chassis of a mobile computing device. [0012] As shown in the detailed view of FIG. 1 , the coupled slot antenna can include a region of the conductive body 110 having a slot 141 and a gap 133 formed therein to define a first antenna arm 135 and a second antenna arm 131. The slot 141 can provide clearance between the main bulk of the conductive body 110 and the antenna arms 135 and 131. In various implementations, the first antenna arm 135 and/or the conductive body 10 can be coupled to the signal feed connection 137. The location of the signal fee connection 137 can be determined based on the frequency bands at which the coupled slot antenna structure 130 will be used. Similarly, the lengths of the first antenna arm 135 and the second antenna arm 131 and the width of the coupling gap 133 can be based on the intended frequency bands.

[0013] Regions 139 represent areas in which insulating material can be disposed to further tune and/or isolate the radiation performance of the coupled slot antenna structure 130. Then insulating material can include various compositions of plastics, resin, tape, fiberglass, carbon, and the like.

[0014] FIG. 2 depicts a close-up view of an example implementation of the present disclosure. In the particular example shown in FIG. 2, the coupled slot antenna structure 130 can be formed at the edge of a metal chassis of a mobile computing device. As such, the first antenna arm 135 and the second antenna arm 131 can have an L-shaped profile that makes up an edge or exterior surface of the mobile computing device. Accordingly, the coupled slot antenna can be formed by initially bending or machining the L-shaped profile of the first antenna ami, also referred to herein as the "feed arm", 135 and the second antenna arm, also referred to herein as the "coupled arm", 131. This can include casting, milling, bending, or stamping the conductive metal body 110 to have the L-shaped profile at the edge at which the coupled slot antenna will be located.

[0015] With the L-shaped profile established for the antenna arms, the slot 141 and the coupling gap 133 can be formed by etching, milling, cutting, or otherwise removing the conductive material of the conductive body 110 in the region of the slot 141 and coupling gap 133. [0016] With the slot 141 and the coupling gap 133 formed, the signal source connection 137 can be coupled to the first antenna arm 135 and/or the conductive body 110. The relative placement of the signal source connection 137 in the slot 141 can be based on the frequency bands and desired performance of the coupled slot antenna structure 130. As such, the signal source connection can be located anywhere along the length of the slot 141.

[0017] The coupled slot antenna structure 130 can be driven by applying an electrical driving signal having particular voltage, current, and/or frequency to the signal source connection 137. In response to the driving signal, the coupled slot antenna structure 130 can capacitively couple the coupled slot structure that includes the coupled arm 131 and/or the coupling gap 133 to generate a slot mode antenna radiation. Because of the feed arm 135 and the coupled arm 131 are separated by the coupling gap 133, the coupled slot antenna structure 130 can also generate a coupled monopole mode antenna radiation. As such, the driving signal applied to the signal source connection 137 can simultaneously generate the two distinctive antenna modes (e.g., the slot mode and the monopole mode).

[0018] In implementations in which the coupled slot antenna structure 30 is used for dual band wireless network communication protocols (e.g., IEEE 802.11), the slot mode antenna radiation can be centered around 2.44 GHz and the coupled monopole mode radiation can be centered around 5.4 GHz.

[0019] The dimensions of the feed arm 135, the coupled arm 131, the coupling gap 133, the slot 141, and the placement of the signal source connection 137 can be determined based on the frequency bandwidths defined in a particular wireless communication protocol. As such, the position of the signal source connection 137 relative to the end feed arm side of the slot 141 can be defined by distance 303, depicted in FIG. 3. Similarly, the position of the signal fee connection 137 relative to the coupling gap 133 can be defined by the distance 305. The length 309 of the coupling arm 131 can be determined in response to the length of the feed arm 135, the width 301 of the slot 141, the width 307 of the coupling gap 133, and/or the placement of the signal fee connection 137. The width 301 of the slot 141 and the width of the coupling gap 307 can similarly be determined in response to the intended frequency bands and the dimensions of the other components of the coupled slot antenna structure 130.

[0020] FIG. 4 depicts a schematic representation of an example coupled slot antenna structure according to various implementations of the present disclosure. In particular, FIG. 4 depicts the electronic schematic equivalents of the various components of the coupled slot antenna structure. The couple arm 131 can correspond to a conductor of a particular length and width coupled to a ground voltage. The ground voltage can be an absolute ground (e.g., 0V) or a relative ground (e.g., a non-zero positive or negative voltage).

[0021] The coupling gap can correspond to a particular free space or insulator material occupied gap having a width 407 between the couple arm 131 and the feed arm 135. As such, the total distance between one end of the coupled arm 131 and the coupling gap 133 is equivalent to the difference between the distance D1 405 and the width G1 407 of the coupling gap 133.

[0022] The signal source connection 137 because it is coupled to the conductive body 110, can be represented as being coupled to ground and the feed arm 135 at a particular point along the length L1 403. The feed arm 135 can also be depicted as a length L1 403 of conductor coupled to ground.

[0023] FIG. 5 depicts a graph 505 of the return loss of an example coupled slot antenna structure having a particular configuration for use in dual band wireless network communication. As shown, the structure of the coupled slot antenna structure can include two relatively wide bandwidths of frequencies 501 and 503 centered at 2.4 GHz and 5 GHz. The slot mode radiation resonates around 2.4 GHz in the coupled monopole mode radiation resonates around 5 GHz.

[0024] FIG. 6 depicts an example mobile computing device 600 in which various examples of the present disclosure can be implemented. As shown, the mobile computing device 600 can include a processor 621. The processor 621 can be coupled to a coupled slot antenna structure 130 and/or a memory 623. The memory 623 can include any combination of transitory and non- transitory computer readable media. As such, the memory 623 can include volatile and nonvolatile memory technologies for storing computer executable code for implementing or driving various examples of the present disclosure. In various examples, the computer executable code stored in the memory 623 can include instructions for performing various operations described herein

[0025] For example, the processor 621 can execute signal driving code 630 that includes instructions for generating signals for driving the signal source connection 137 of the coupled slot antenna structure 130 as described herein. In various other examples, the processor 621 can execute the multi- band wireless communication protocol code 630 to generate signals for driving the signal source connection 137 to generate wireless communication signals using the coupled slot antenna structure 130 using the two antenna modes. In related implementations, the processor 621 can execute executable code stored in the memory 623 to detect wireless communication signals received by or excited in the coupled slot antenna structure 130 to implement two-way data communications.

[0026] As described herein, various examples of the present disclosure can be implemented as any combination of executable code and hardware. For example, implementations can include computer executable code executed by a processor 621 or mobile computing device 600 to cause two antenna mode resonances in the coupled slot antenna structure 130 to communicate according to a particular wireless communication protocol. As such, the functionality of processor 621 or mobile computing device 600 described herein can be implemented as executable code that includes instructions that when executed by the processor cause the processor to perform operations, or generate signals that cause other devices (e.g., components of the mobile computing device 600) to perform operations, in accordance with various implementations and examples described herein.

[0027] For example, the functionality for driving signal source connection 137 can be implemented as executable signal driving code 630 stored in the memory 623 and executed by processor 621. Similarly, the functionality for modulating the drive signals to communicate wirelessly using a corresponding multi-band wireless communication protocol can be implemented as multi- band wireless communication protocol code 640 stored in memory 623 and executed in processor 621 [0028] The processor 621 may be a microprocessor, a micro-controller, an application specific integrated circuit (ASIC), or the like. According to an example implementation, the processor 621 is a hardware component, such as a circuit.

[0029] The memory 623 can include any type of transitory or non- transitory computer readable medium. For example the memory 623 can include volatile or non-volatile memory, such as dynamic random access memory (DRAM), electrically erasable programmable read-only memory (EEPROM), magneto-resistive random access memory (MRAM), memristor, flash memory, floppy disk, memristor array, a compact disc read only memory (CD-ROM), a digital video disc read only memory (DVD-ROM), or other optical or magnetic media, and the like, on which executable code may be stored.

[0030] FIG. 7 depicts a flowchart of an example method 700 for generating two antenna modes in a coupled mode antenna structure 130. The method 700 can begin at box 710 by providing a coupled slot antenna structure 130 in a mobile computing device or other computing device. As described herein, the coupled slot antenna structure 130 can be integrated into a metal or conductive body 110 of the mobile computing device. As such, a chassis or decorative metal housing of a mobile computing device can be used to implement examples of the coupled slot antenna structure 130 described herein. Providing the coupled slot antenna structure 130 can include forming the conductive body 110 to include the feed arm 135 and the coupled arm 131 separated from the conductive body 110 by a slot 141 and from each other by a coupling gap 133.

[0031] At box 720, the processor 621 or other component of a mobile computing device can generate a first signal to drive the signal source connection 137 to capacitively couple the coupled antenna arm 131 to generate a first antenna mode. As described herein, the first antenna mode can include a slot antenna mode having frequency resonances at

approximately 2.4 GHz for use in wireless network communication protocols. [0032] At box 730, the processor 621 or other component of the mobile computing device can generate a second signal to drive the signal source connection 137 to cause a second antenna mode in the feed arm antenna 135. The second antenna mode can include a coupled monopole mode antenna radiation with frequency resonances at approximately 5 GHz for use in a wireless network communication protocol. In some implementations, the first and second signals can be the same signal.

[0033] These and other variations, modifications, additions, and improvements may fall within the scope of the appended claims(s). As used in the description herein and throughout the claims that follow, "a", "an", and "the" includes plural references unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the elements of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or elements are mutually exclusive.

Claims

What is claimed is:

1. An couple slot antenna comprising:

a planar conductive body comprising an edge and a slot to form the coupled slot antenna comprising:

a first antenna arm coupled to the edge of the conductive body; and

a second antenna arm coupled to the edge of the conductive body and separated from the first antenna arm by a coupling gap.

2. The couple slot antenna of claim 1 wherein the conductive body comprises a metal chassis of a mobile computing device.

3. The couple slot antenna of claim 2 wherein the chassis comprises a housing of the mobile computing device.

4. The couple slot antenna of claim 1 wherein the slot comprises free space adjacent, or an insulating material coupled, to the planar conductive body, the first antenna arm, and the second antenna arm.

5. The couple slot antenna of claim 1 wherein the first antenna arm comprises a first length and the second antenna arm comprises a second length, the first length being longer that the second length.

6. The couple slot antenna of claim 5 further comprising a signal source connection coupled to the planar conductive body on a first side of the slot and coupled to the first antenna arm on a second side of the slot at a particular location along the first length of the first antenna arm.

7. The couple slot antenna of claim 5 wherein the first length, the second length, the particular location along the first length, and a dimension of the coupling gap are dimensioned to generate a first antenna mode and a second antenna mode when the signal source connection is driven with a oarticular sianal.

8. The couple slot antenna of claim 7 wherein the first antenna mode is a slot mode.

9. The couple slot antenna of claim 7 wherein the second antenna mode is a coupled monopole mode.

10. A method comprising;

providing a planar conductive body comprising an edge and a slot to form a coupled slot antenna comprising:

a first antenna arm coupled to the edge of the conductive body and extended in a first direction parallel to the edge;

a second antenna arm coupled to the edge of the conductive body and extended in a second direction parallel to the edge and separated from the first antenna arm by a coupling gap; and

a signal source connection coupled to the planar conductive body on a side of the slot and coupled to the first antenna arm at a particular location; and

driving the signal source connection to generate a first antenna mode and a second antenna mode. i i . The method of claim 10, wherein first antenna mode is a slot mode and the second antenna mode is a coupled monopole mode.

12. The method of claim 10, wherein the first antenna mode and the second antenna mode are compatible with a multi-band wireless data communication protocol.

13. An mobile computing device comprising:

a processor;

a planar conductive body comprising an edge and a slot to form a coupled slot antenna comprising: a first antenna arm coupled to the edge of the conductive bodv and extended in a first direction Darallel to the edae:

a memory comprising executable code comprising instructions that when executed by the processor cause the processor to drive the signal source connection to generate a first antenna mode and a second antenna mode using the first antenna arm and the second antenna arm.

14. The mobile computing device of claim 13, wherein the instructions that cause the processor to drive the signai source further cause the processor to generate wireless communication signals.

15. The mobile computing device of claim 14, wherein the wireless

communication signals are compatible with a multi-band wireless data communication protocol.