WO2022159087A1

WO2022159087A1 - Antenna for devices

Info

Publication number: WO2022159087A1
Application number: PCT/US2021/014267
Authority: WO
Inventors: Cheng-Ming Lin; Chien-Pai Lai; Chun-Chih Liu
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2021-01-21
Filing date: 2021-01-21
Publication date: 2022-07-28

Abstract

Example devices with an antenna are described. In an example, the antenna may be implemented onto an antenna circuit board. The device may further include an antenna ground plane having a slot along it's a longitudinally extending first edge. The device may further include a feed element having a first end connected to the antenna circuit board at a connection point.

Description

ANTENNA FOR DEVICES

BACKGROUND

[0001] In electronic devices, an antenna may be used to transmit or receive electromagnetic signals from other neighboring electronic devices. Such electronic devices may have a metallic antenna which is excited by applying electromagnetic signals through any feeding arrangement. The applied electromagnetic signal may thus result in generation of electrical surface current on the surface of the antenna. Such electrical surface cunent in turn generates near field electromagnetic energy, based on which a Specific Absorption Ratio (SAR) value of the device may depend.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The following detailed description references the drawings, wherein: [0003] FIG. 1 illustrates a communication device comprising an example antenna, in accordance with an example of the present subject matter;

[0004] FIG. 2 illustrates an electronic device comprising an example antenna, in accordance with an example of the present subject matter;

[0005] FIG. 3 illustrates a computing device comprising an example antenna, in accordance with an example of the present subject matter; and

[0006] FIGS. 4-5 illustrate an example antenna assembly, in accordance with another example of the present subject matter.

[0007] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

DETAILED DESCRIPTION

[0008] Electronic devices, such as personal computers, mobile phones, tablet computers, wrist watches, and other hybrid functional devices, may include an antenna, which may enable wireless communication with other devices over a network. In order to communicate, the antenna converts an electromagnetic signal applied from an excitation source into a Radio Frequency (RF) wave which may be transmitted over air In a similar manner, antennas may be used for receiving the RF wave transmitted by another electronic device.

[0009] The antenna may be implemented as an antenna assembly on an eiectronic circuit board, such as a Printed Circuit Board (PCS). The eiectronic circuit board (referred to as a circuit board) may be connected to a ground piane. The ground plane is a large conducting surface which is connected to the ground terminal of a power supply and serves as a return path for current from different components of the circuit board. The antenna assembly may further include a feed line which may pass through the ground plane. The feed line is to provide electromagnetic signals to the antenna via a connection point. On applying electromagnetic signais through the feed line, the antenna may be excited to generate a RF wave for transmission through air to be received by other electronic devices .

[0010] The excitation of the antenna may result in generation of an electrical surface current. The electrical surface current may propagate on the surface of the circuit board. In some cases, the electrical surface current may transfer to the ground piane which in turn may contribute to near field electromagnetic energy, in an example, the intensity of near field electromagnetic energy may be comparatively high at the connection point between the feed line and the antenna due to the discontinuity in transmission of electromagnetic signals from feed line to antenna.

[0011] The presence of such near field electromagnetic energy thus may contribute to increase the Specific Absorption Ratio (SAR) value for the electronic device. To limit and control the SAR value increased due to the electrical surface current, the power level of the antenna is accordingly adjusted or reduced which in turn may reduce the antenna gain, and thereby may limit the efficiency of the antenna.

[0012] Examples of an electronic device comprising an antenna are described. The electronic device includes an antenna mounted on an electronic circuit board, such as a Printed Circuit Board (PCB). The electronic circuit board bearing the antenna may be coupled with an antenna ground plane. The antenna ground plane may further include a first edge which extends longitudinally along the electronic circuit board. Through the antenna ground plane, a feed element is provided. The feed element may extend along the first edge of the antenna ground plane, with one of the ends of the feed element connected to the electronic circuit board at a connection point. In addition, another end of the feed element may be connected to an external excitation source which may provide the electromagnetic signal to the antenna. The antenna ground plane may further include a slot. In an example, the slot is a through hole or groove which may be provided along the first edge of the antenna ground plane and may be located at the connection point between the feed element and the electronic circuit board with remaining portion of the feed element extending over the ground plane.

[0013] In operation, when the antenna is excited with an electromagnetic signal through the feed element, an electrical surface current may be generated on the surface of the electronic circuit board. In an example, the electromagnetic signals provided to the antenna may result in generation of an electromagnetic field which in turn may push the surface charges of the electronic circuit board to produce the electrical surface current. The generated electrical surface current may be transferred to the connected antenna ground plane.

[0014] Further, excitation of antenna via the feed element may results in generation of a magnetic current around the aperture formed by the slot provided on the antenna ground plane. The magnetic currents thus generated around the aperture may cancel the electrical surface current propagating on the antenna ground plane or reduce the effect of electrical surface current. This in turn may reduce the near field electromagnetic energy which may be caused due to the discontinuity in the transmission of electromagnetic signals from the feed element to the electronic circuit board. In the present example, such reduction in near field electromagnetic energy may further reduce the SAR value for the electronic device and improve the antenna gain as well.

[0015] In another example, the longitudinally extending antenna ground plane may include a plurality of slots along the first edge. In one example, the first of the plurality of slots may be located at the connection point between the feed element and electronic circuit board, and the remaining portion of the feed element may extend over the remaining plurality of slots. It may be noted that, the pattern of extension of feed element over the antenna ground plane, and the location or dimension of plurality of slots may change based on the type and function performed by different devices. Further, in addition to the electronic device, the above described antenna assembly may be implemented on variety of different devices, such as computing devices, communication devices, without limiting the scope of the present subject matter. The aforementioned configuration of the antenna assembly provides higher antenna gain as well as reduced SAR value with similar input applied. The slots may be of any shape. Examples of such shapes include, but may not be limited to, rectangle, square, circle, or oval.

[0016] The above aspects and other examples are further described in conjunction with the figures, and in associated description below. It may be noted that the description and figures merely illustrate principles of the present subject matter. Therefore, various arrangements that encompass the principles of the present subject mater, although not explicitly described or shown herein, may be devised from the description, and are included within its scope. These and other examples are provided in further detail in conjunction with FIGS. 1-5, [0017] FIG. 1 illustrates an example communication device 100 comprising an antenna 102 implemented as part of an antenna assembly. As would be explained, the present antenna assembly facilitates reduction of SAR value without adversely impacting antenna gain for a given power input applied to the antenna 102. In an example, the antenna 102 may be implemented within an antenna circuit board 104. In an example, the antenna 102 may be physically implemented, such as mounted, microchipped, or embedded onto the antenna circuit board 104,

[0018] The antenna circuit board 104 is further coupled to an antenna ground plane 106. The antenna ground plane 106 may be a conductive portion of the antenna circuit board 104, which may be further connected to a power supply ground terminal of the communication device 100. The antenna ground plane 106 may, amongst other things, serve as a return path for current from different components of the communication device 100 on the antenna circuit board 104. [0019] The antenna ground plane 106 may include a first edge 108 extending longitudinally along the antenna circuit board 104. Although depicted having a rectilinear shape, the antenna ground plane 106 may be of any other shape, without deviating from the scope of the present subject matter. The communication device 100 may further include a feed element 110 having a first end 112. The feed element 110 may be an insulated conducting wire capable of providing electromagnetic signal to the antenna circuit board 104. In an example, the first end 112 may be connected to the antenna circuit board 104 at a connection point 114. A second end of the feed element 110 may be connected to an external excitation source for providing electromagnetic signal to the antenna circuit board 104 via the connection point 114.

[0020] The antenna ground plane 106 may further include a first slot 116 and a second slot 118 located along the first edge 108. In an example, the first slot 116 and second slot 118 are through spaces formed on the antenna ground plane 106. Although depicted having a rectilinear shape, the first slot 116 and the second slot 118 may be of any shape. Examples of such shapes include, but is not limited to, rectangle, square, circle, or oval, without deviating from the scope of the present subject matter. In an example, the position of the first slot 116 and the second slot 118 on the antenna ground plane 106 may depend on the extension of the feed element 110 over the antenna ground plane 106. In one example, the first slot 116 may be located at the connection point 114 between the first end 112 of the feed element 110 and the antenna circuit board 104 with the remaining portion of the feed element 110 extending over the second slot 118.

[0021] In operation, on application of electromagnetic signal through the external excitation source via the feed element 110, the antenna 102 may be excited, as a result of which the applied electromagnetic signal is converted to transmittable RF waves. During such excitation, an electrical surface current may propagate on the surface of the antenna circuit board 104, which in turn is transferred to the antenna ground plane 106. On the other hand, due to such excitation through feed element 110, a magnetic current may be generated at apertures defined by the first slot 116 and the second slot 118. The magnetic current thus generated may cause to reduce the effects of electrical surface current produced in the antenna ground plane 106. This in turn may further reduce ‘near field’ electromagnetic energy that may have been produced due the electrical surface current. This in turn may further lead to reduction of the SAR value for the communication device 100. In an example, the intensity of near field electromagnetic energy cause due to electrical surface current may be comparatively high at the connection point 114 between the feed element 110 and the antenna circuit board 104 due to the discontinuity in transmission of electromagnetic signals from feed dement 110 to antenna circuit board 104. To this end, the electrical surface current on the surface of the antenna ground plane 106 may get cancelled by the magnetic current resulting in reduced near field electromagnetic energy around the first slot 116 and the second slot 118, [0022] The above example has been explained with respect to the communication device 100 having an antenna ground plane 106 with the first slot 116 and the second slot 118. The present subject matter, however, is not limited to such communication devices wherein the antenna ground plane 106 has the first slot 116 and the second slot 118. The present subject mater may include other types of devices, such as a computing device. These and other exampies are further explained in conjunction with FIGS, 2-3.

[0023] FIG. 2 Illustrates an example electronic device 200 comprising an antenna 202, as per an example. The electronic device 200 may be similar to the communication device 100 (as described with respect to FIG. 1). The electronic device 200 may include an electronic circuit board 204 comprising an antenna 202. In one exampie, the antenna 202 may be mounted, microchipped, or embedded onto the electronic circuit board 204.

[0024] Within the electronic device 200, the electronic circuit board 204 is further coupled to an antenna ground plane 206. In an example, the antenna ground plane 206 is a large conducting surface which is connected to the ground terminal of the power supply and serves as a return path for current from electronic circuit board 204. The antenna ground plane 206 may extends longitudinally along the antenna circuit board 204. In an example, the antenna ground plane 206 may include a first edge 208 which may extend longitudinally along the electronic circuit board 204. In another example, the antenna ground plane 206 may be mechanically, yet removably, coupled to the electronic circuit board 204. The longitudinally extending antenna ground plane 206 may further include a slot 210 along its first edge 208. The slot 210 is a through space formed on the antenna ground plane 206 having a defined shape. Example of such shapes include, but may not be limited, rectangle, square, circle, or oval. In another example, the antenna ground plane 206 may further include a second slot, such as the second slot 118 (as described in conjunction with FIG. 1).

[0025] The electronic device 200 may further include a feed element 212 passing through the first edge 208 of the antenna ground plane 206. The feed element 212 may further include a first end 214 connected to the electronic circuit board 204 at a connection point 216, such that the connection point 216 is accommodated in the slot 210. The first end 214 of the feed eiement 212 connects the antenna 202 with an external excitation source. Examples of such feed eiement 212 include, but may not be limited to, an optical fibre cable, coaxial cable, twin-lead cable, or a ladder line cable. In case of microwave frequencies, the feed element 212 may be an appropriate waveguide.

[0026] in an example, the feed element 212 may further include a second end which may be connected to an externa! excitation source for inputting an electromagnetic signal to the electronic circuit board 204. In one example, the slot 210 is located at the connection point 216 between the feed element 212 and the electronic circuit board 204 with the remaining portion of the feed element 212 extending through the antenna ground plane 206.

[0027] Similar to the operation of the communication device 100, upon excitation of the antenna 202, a magnetic current may be generated at the aperture defined by the siot 210 which may reduce effect of a portion of the electrical surface current produced in the antenna ground plane 206, This in turn may further reduce the near field electromagnetic energy caused due to the discontinuity at the interconnection of the feed eiement 212 with the electronic circuit board 204. Such reduction in near field electromagnetic energy may further reduce the SAR value for the electronic device 200 and improves antenna gain as well.

[0028] FIG. 3 illustrates an example computing device 300 comprising an antenna 302, as per an exampie. The computing device 300 may be similar to the communication device 100 and electronic device 200 (as described with respect to FIG. 1-2) The computing device 300 may include an antenna circuit board 304 onto which the antenna 302 may be mounted, microchipped, or embedded. The antenna Circuit board 304 is further coupled to an antenna ground piane 306 which in turn include a first edge 308. In one example, the first edge 308 of the antenna ground plane 306 may extends longitudinally along the antenna circuit board 304. Although depicted having the illustrated shape and orientation, the antenna ground plane 306 may be of any shape and may be positioned in any manner, without deviating from the scope of the present subject matter.

[0029] The longitudinally extending antenna ground plane 306 may further include a feed element 310 extending along the first edge of the antenna ground plane 306. In an example, the feed element 310 may be any type of insulated cable which may enable propagation of electromagnetic signal through it. The feed element 310 may further include a first end 312 which may be connected to the antenna circuit board 304 at a connection point 314. In an example, the feed element 310 makes an electrical connection with the antenna ground plane 306 through the connection point 314. To reduce the near field electromagnetic energy, the antenna ground plane 306 may further include a plurality of slots 316-1, 316-2, 316-N (referred to as slots 316) along its first edge 308. In an example, the plurality of slots 316 are arranged equidistant with respect to each other and the feed element 310 extends over the plurality of slots 316. In one example, the first slot 316-1 of the plurality of slots 316 may be located at the connection point between the feed element 310 and the antenna circuit board 304 with the remaining portion of the feed element 310 may extend over the remaining slots 316.

[0030] Although depicted having a certain shape and iocation, the slots 316 may be of any shape and positioned based on the extension of the feed element 310 over the antenna ground plane 306. Examples of shapes include, but may not be limited to, rectangle, square, circle, or oval. The feed element 310 may further include a second end which may be connected to an external excitation source to provide electromagnetic signals to the antenna circuit board 304 through the connection point 314. In an example, the external excitation source includes an energy source which provide adequate input to the antenna circuit board 304. Although depicted extending along the first edge 308 of the antenna ground plane 306, the feed element 310 may extends over the antenna ground plane 306 in any other way, without deviating from the scope of the present subject matter,

[0031] As described previously, the extension of the feed element 310 over the slots 316 may generate a magnetic current around the aperture formed by the slots 316 which may reduce the effect of a portion of the electrical surface current propagating on the surface of the antenna ground plane 306. This in turn may further reduce near field electromagnetic energy caused due the surface electric current, which may reduce the SAR value for the computing device 300. The generation of electncai and magnetic current on an antenna assembly is further explained in detail in conjunction with FIG. 4-5.

[0032] FIG. 4-5 illustrate an antenna assembly 400, as per an example. The antenna assembly 400 may be implemented in a variety of devices, such as the communication device 100, the electronic device 200, and the computing device 300, The antenna assembly 400, thus described, may be implemented in any other device that is to transmit or receive electromagnetic signals for communication.

[0033] In the present example, the antenna assembly 400 includes a circuit board 402 onto which an antenna 404 may be provided. In an example, the antenna 404 may be a monopole antenna or a microstrip antenna. In another example, the antenna 404 may be a patch antenna, an inverted-F antenna, or a planar inverted-F antenna (PIFA). In such example, the antenna 404 along with other RF-based components (not shown in FIG. 4) may be implemented and manufactured as part of the circuit board 402. In yet another example, the antenna 404 may be Wireless wide area network (WWAN) antenna. Wireless local area network (WLAN) antenna, Ultra-Wide Band (UWB) antenna, Ultra High Frequency (UHF) antenna, and Microwave antenna.

[0034] The antenna assembly 400 may further include an antenna ground plane 406 having a first edge 408 extending along the circuit board 402. The antenna ground plane 406 may be a conductive portion of the circuit board 402 which is connected to a power supply ground terminal of a device within which the antenna assembly 400 may be implemented. The antenna ground plane 406 may, amongst other things, serve as a return path for current from different components of the device (such as the communication device 100, the electronic device 200, or the computing device 300) on the circuit board 402.

[0035] The antenna assembly 400 may further include a feed element 410 having a first end 412, which may be connected to the circuit board 402 at a connection point 414. In an example, the feed element 410 may further include a second end 420 connected to an external excitation source (not shown in FIG. 4-5) for inputting electromagnetic signal to the circuit board 402. In an example, the feed element 410 may extend along the first edge 408 of the antenna ground plane 406. The antenna ground plane 406 may further include a first slot 416 and a second slot 418.The first slot 416 and the second slot 418 may be one of a groove, slit, opening or aperture provided along a first edge 408 of the antenna ground plane 406. Although depicted having a certain shape and position, the first slot 416 and the second slot 418 may be of any shape and may be positioned on the antenna ground plane 406 based on the extension of the feed element 410 over the antenna ground plane 406, without deviating from the scope of the present subject matter. In one example, the first slot 416 may be positioned at the connection between the feed element 410 and the circuit board 402 with the remaining portion of the feed eiement 410 extends over the second slot 418. In addition to the first slot 416 and the second slot 418, the antenna ground plane 406 may include an additional number of slots. In an example, the dimension of the first slot 416, the second slot 418, and any additional number of slots may depend on the type of feed element extending along the antenna ground plane.

[0036] In operation, on application of electromagnetic signal through the external excitation source via feed element 410, the antenna 404 of the circuit board 402 is excited to convert the applied electromagnetic signal to Radio Frequency (RF) waves transmittable over air. On the other hand, on receiving RF waves, the antenna 404 is excited to convert the RF waves into electromagnetic signal. During such excitations, an electrical surface current, such as electrical surface current 502, may propagate on the surface of the circuit board 402, which in turn is transferred to the antenna ground plane 406. In an example, applied electromagnetic signal may generate an electromagnetic field which in turn may pushes the surface charges of the electronic circuit board around to form such electrical surface current.

[0037] The excitation of antenna 404 through feed element 410 may result in generation of a magnetic current, such as magnetic current 504, around the aperture formed by the first slot 416 and the second slot 418. It may be noted that, the discontinuity in transmission of electromagnetic signals from the feed eiement 410 to the circuit board 402 at the connection point 414 may results in higher near field electromagnetic energy around the connection point 414. To this end, effects of the electrical surface current 502 propagating on the surface of the antenna ground plane 406 around the first slot 416 and the second slot 418 is reduced significantly. Due to such reduction in electrical surface current 502, the near fieId electromagnetic field is reduced resulting in reduction of SAR value.

[0038] Although implementations of present subject matter have been described in language specific to structural features and/or methods, it is to be noted that the present subject matter is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained in the context of a few implementations for the present subject matter.

Claims

Claims:

1. A communication device comprising: an antenna circuit board, wherein the antenna circuit board comprises an antenna; an antenna ground plane comprising a first edge extending longitudinal!/ along the antenna circuit board; a feed element having a first end, wherein the feed element extends aiong the first edge of the antenna ground plane and the first end of the feed element is connected to the antenna circuit board at a connection point; and a first slot and a second slot provided along the first edge of the antenna ground plane, wherein the first slot is located at the connection point between the feed element and the antenna circuit board.

2. The communication device as claimed in claim 1 , wherein a shape of the first slot and the second slot is rectangle, square, circle, or oval.

3. The communication device as claimed in claim 1 , wherein the feed element further comprises a second end, wherein the second end is connected to an external excitation source of an electromagnetic signal.

4. The communication device as claimed in claim 1, where the antenna ground plane further comprises a further plurality of slots positioned along the first edge of the antenna ground plane.

5. The communication device as claimed in claim 4, wherein the first slot, the second slot, and the further plurality of slots are arranged linearly and equidistant from each other.

6. The communication device as claimed in claim 4, wherein the feed element extends through the further plurality of slots.

7. The communication device as claimed in claim 1, wherein the antenna is a Wireless wide area network (WWAN) antenna, Wireless locai area network (WLAN) antenna, Ultra-Wide Band (UWB) antenna, Ultra High Frequency (UHF) antenna, or Microwave antenna.

8. An electronic device comprising: an electronic circuit board; an antenna provided onto the electronic circuit board; an antenna ground plane comprising a first edge extending longitudinally along the electronic circuit board, wherein the antenna ground plane further comprises a slot positioned along the first edge of the antenna ground plane; and a feed element comprising a first end extending along the first edge of the antenna ground plane and connected to the electronic circuit board at a connection point, wherein the connection point is accommodated in the slot.

9. The electronic device as claimed in claim 8, wherein the antenna ground plane further comprises a second slot positioned on first edge of the antenna ground plane.

10. The electronic device as claimed in claim 8, wherein the feed element further comprises a second end connected to an excitation source to provide an electromagnetic signal to the electronic circuit board through the connection point.

11. The electronic device as claimed in claim 9, wherein the feed element extends along the antenna ground plane and through the second slot.

12. A computing device comprising: an antenna circuit board, wherein the antenna circuit board comprises an antenna; an antenna ground plane comprising a first edge extending longitudinally along the antenna circuit board; a feed element comprising a first end extending along the first edge of the antenna ground plane, wherein the first end of the feed element is connected to the antenna circuit board at a connection point; and a plurality of slots provided along the first edge of the antenna ground plane, wherein a first slot of the plurality of slots is positioned at the connection point between the feed element and the antenna circuit board..

13. The computing device as claimed in claim 12, wherein the feed element is to provide an electromagnetic signal to the antenna circuit board through the connection point.

14. The computing device as claimed in claim 12, wherein the feed element further comprising a second end connected to an external excitation source to feed an electromagnetic signal to the antenna circuit board.

15. The computing device as claimed in claim 12, wherein a dimension of the plurality of slots is based on the feed element extending along the antenna ground plane.