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1. WO2007109512 - ANTENNE À COUCHES MULTIPLES DESTINÉE À DES APPLICATIONS SANS FIL

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

MULTIPLE LAYER ANTENNA FOR WIRELESS APPLICATIONS

FIELD OF THE INVENTION
This invention relates generally to wireless communication applications, and more specifically, to multiple layer antennas for wireless communication applications.

BACKGROUND OF THE INVENTION
Most devices that communicate wirelessly include one or more antennas to transmit and receive wireless signals. For instance, during wireless data
transmissions, antennas convert electrical signals into electromagnetic fields, which wirelessly radiate to remote communication devices. This conversion between electrical signals and electromagnetic fields is highly dependent upon the physical structure and resonance behavior of the antennas. As is common in communication fields, there is a ubiquitous desire to reduce the size of communication systems without diminishing electrical performance. This task, however, proves exceedingly difficult, as physical reductions to the antennas often alters their resonance behavior, which in turn degrades wireless communications.
Figure 1 shows a communication system 100. Referring to Figure 1, the communication system 100 includes an antenna 110 for communicating wirelessly. The antenna 1 10 is a metal trace formed on a top face of a printed circuit board (PCB) 120, and designed to have a resonance behavior optimized for a predetermined wireless signal frequency. The antenna 1 10 converts electrical signals from circuitry 130 into the electromagnetic fields and transmits the electromagnetic fields as wireless signals. The antenna 110 also receives electromagnetic fields and converts them into electrical signals for the circuitry 130. The circuitry 130 exchanges the electrical signals with the antenna 1 10 through an antenna interface 140. Although antenna 110 adequately transmits and receives wireless signals, the footprint that the antenna 1 10 requires on the PCB 120 limits the ability of system designers to reduce the overall size of the communication system 100. Since the footprint of the antenna 1 10 consumes a significant portion of the PCB 120, the need remains for an antenna with a reduced footprint that does not degrade electrical performance.

Docket No. 5087-251 1 CD06012 DESCRIPTION OF THE DRAWINGS
The invention may be best understood by reading the disclosure with reference to the drawings.
Figure 1 is a block diagram of a communication system.
Figures 2-4 are block diagrams of embodiments of a wireless communication device.
Figure 5 is a flowchart of the wireless communication device shown in Figures 2-4.

DETATLED DESCRIPTION
Figures 2-4 are block diagrams of embodiments of a wireless communication device 200. Specifically, Figure 2 shows a top view embodiment of the wireless communication device 200, Figure 3 shows a bottom view embodiment of the wireless communication device 200, and Figure 4 shows a cross-sectional side view embodiment of the wireless communication device 200.
Referring to Figures 2-4, the wireless communication device 200 includes a multi-layer antenna for transmitting and receiving wireless communications. The multi-layer antenna includes a first antenna layer 210 and a second antenna layer 230. The first and second antenna layers 210 and 230 may have a resonance behavior that optimizes wireless transmissions and receptions at a predetermined signal frequency. The first antenna layer 210 may be formed on a top surface of a base 240 and a second antenna layer 230 may be formed on a bottom surface of the base 240. For instance, the first and second antenna layers 210 and 230 may be configured in a stack with the base 240 separating the antenna layers 210 and 230. By stacking the first and second antenna layers 210 and 230, the multi-layer antenna has a reduced footprint or requires a base 240 with less surface area. Although Figures 2-4 show two antenna layers 210 and 230 formed on opposite sides of the base 240, some embodiments may include more than two antenna layers and/or form them on various sides or portions of the base 240.
The first and second antenna layers 210 and 230 are preferably aligned, e.g., according to their vertical members, allowing electrical signals to propagate in same direction through the vertical members. This alignment of the first and second antenna layers 210 and 230 may prevent cancellation of wireless signals generated by first and second antenna layers 210 and 230 due to destructive interference.

Docket No. 5087-251 2 CD06012 Λn antenna inter-connector 220 couples the first and second antenna layers 210 and 230 through the base 240. The antenna inter-connector 220 may be a conducting via that allows electrical signals to pass between the first and second antenna layers 210 and 230. The first and second antenna layers 210 and 230 may be metal traces or any other medium capable of transmitting and/or receiving wireless signals. The base 240 may be a printed circuit board (PCB) or any other medium capable of coupling the multi-layer antenna.
The base 240 may include a bottom metal plate 270 on the bottom surface that may be coupled to circuitry 250 and the first antenna layer 210. The first antenna layer 210 may couple to the base 240 with at a connection point 280. The connection point 280 may be a conducting via that electrically couples the first antenna layer 210 to a ground.
The wireless communication device 200 includes circuitry 250 for exchanging electrical signals with the first antenna layer 210 through an antenna interface 260. During wireless transmissions, the circuitry 250 provides electrical signals to the first antenna layer 210 through the antenna interface 260, where the first and second antenna layers 210 and 230 convert the electrical signals into wireless signals for transmission. The first and second antenna layers 210 and 230 convert the electrical signals into wireless signals according to the resonance behavior of the multi-layer antenna. In some embodiments, the first and second antenna layers 210 and 230 may convert the electrical signals into electromagnetic field signals that radiate wirelessly from the first and second antenna layers 210 and 230.
During wireless reception, the first and second antenna layers 210 and 230 receive wireless signals, convert them into electrical signals, and provide them to the circuitry 250 through the antenna interface 260. In some embodiments, the first and second antenna layers 210 and 230 may convert electromagnetic field signals into the electrical signals. The first and second antenna layers 210 and 230 convert the wireless signals into electrical signals according to the resonance behavior of the multi-layer antenna. The wireless communication device 200 may be any device or located within any device that communicates wirelessly, such as USB modules or peripheral devices, cell phones, computers, personal digital assistants (PDAs), etc.
Figure 5 is a flowchart of the wireless communication device 200 shown in Figures 2-4. Referring to Figure 5, when transmitting wireless signals with a multilayer antenna, a first antenna layer 210 receives electrical signals in the form of a

Docket No. 5087-251 3 CD06012 transmission current 310 and converts the electrical signals into wireless signals. The first antenna layer 210 may receive the transmission current 310 from the circuitry 250 (Figures 2 and 4) via the antenna interface 260 (Figures 2-4). The antenna interface 260 may also include a connection point 280 that may couple the first antenna layer 210 to a ground.
This electrical-to-wireless signal conversion occurs by propagating the transmission current 310 through the first and second antenna layers 210 and 230, where the resonance behavior of the antenna layers 210 and 230 generates electromagnetic field signals. These electromagnetic field signals radiate wirclessly from the first and second antenna layers 210 and 230.
In some embodiments, each antenna layer 210 and 230 generates an electromagnetic field signal from the electrical signals. Accordingly, the wireless communication device 200 may minimize transmission-field interference between these multiple electromagnetic field signals according to the physical alignment of the first and second antenna layers 210 and 230 and the flow of the transmission current 310 along their vertical members.
The transmission current 310 flows between the two antenna layers 210 and 230 through the antenna inter-connector 220. To avoid possible far-field cancellation of the electromagnetic field signals generated by the first and second antenna layers 210 and 230, the first and second antenna layers 210 and 230 are aligned according to their vertical members. This alignment of the first and second antenna layers 210 and 230 allows the transmission current 310 to propagate in same direction through the vertical members, thus minimizing constructive interference between electromagnetic fields generated and transmitted by the first and second antenna layers 210. Although Figure 5 shows a transmission current flow embodiment, the first and second antenna layers 210 and 230 may induce a current flow that is similarly aligned, yet in the opposite direction, responsive to the reception of wireless signals.
By utilizing multiple sides of the base 240 and intelligently aligning current flow through the first and second antenna layers 210 and 230, embodiments of the present invention may reduce an antenna footprint without degrading electrical performance. Thus, the addition of a multi-layer antenna allows system designers the freedom to reduce the overall size of their wireless communication devices.
One of skill in the art will recognize that the concepts taught herein can be tailored to a particular application in many other advantageous ways. In particular,

Docket No. 5087-251 4 CD06012 those skilled in the art will recognize that the illustrated embodiments are but one of many alternative implementations that will become apparent upon reading this disclosure. For instance, the configuration of the first and second antenna layers 210 and 230 shown and described above is one of many embodiments for multiple layer antennas. Those skilled in the art will recognize various multi-layer antenna implementations.
The preceding embodiments are exemplary. Although the specification may refer to "an", "one", "another", or "some" embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment.

Docket No. 5087-251 5 CD06012