Electronic device

An electronic device includes a first metal element, a second metal element, a feeding radiation element, a first radiation element, a second radiation element, a third radiation element, and a matching radiation element. The first metal element is coupled to a ground voltage. The second metal element is separated from the first metal element. The first radiation element and the second radiation element are coupled to the feeding radiation element. The third radiation element is coupled to the second metal element, and is adjacent to the first radiation element and the second radiation element. An antenna structure is formed by the feeding radiation element, the first radiation element, the second radiation element, the third radiation element, and the matching radiation element. A sensing pad is formed by the second metal element and the third radiation element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of Taiwan Patent Application No. 108143909 filed on Dec. 2, 2019, the entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

Field of the Invention

The disclosure generally relates to an electronic device, and more particularly, it relates to an electronic device for integrating an antenna structure with a sensing pad.

Description of the Related Art

With the advancements being made in mobile communication technology, mobile devices such as portable computers, mobile phones, multimedia players, and other hybrid functional portable electronic devices have become more common. To satisfy consumer demand, mobile devices can usually perform wireless communication functions. Some devices cover a large wireless communication area; these include mobile phones using 2 G, 3 G, and LTE (Long Term Evolution) systems and using frequency bands of 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, 2300 MHz, and 2500 MHz. Some devices cover a small wireless communication area; these include mobile phones using Wi-Fi and Bluetooth systems and using frequency bands of 2.4 GHz, 5.2 GHz, and 5.8 GHz.

Antennas are indispensable components of mobile devices for wireless communication. To meet the requirements of SAR (Specific Absorption Rate) set by the government, a designer often controls RF (Radio Frequency) power relative to an antenna by incorporating a proximity sensor (P-sensor) into a mobile device. However, the sensing pad of a proximity sensor tends to interfere with the antenna and degrade the radiation efficiency of the antenna. Accordingly, there is a need to propose a novel solution to overcome this problem with the prior art.

BRIEF SUMMARY OF THE INVENTION

In an exemplary embodiment, the disclosure is directed to an electronic device that includes a first metal element, a second metal element, a feeding radiation element, a first radiation element, a second radiation element, a third radiation element, and a matching radiation element. The first metal element is coupled to a ground voltage. The second metal element is separated from the first metal element. A positive electrode of a signal source is coupled to the feeding radiation element, and a negative electrode of the signal source is coupled to the first metal element. The first radiation element is coupled to the feeding radiation element. The second radiation element is coupled to the feeding radiation element. The second radiation element and the first radiation element substantially extend in opposite direction. The third radiation element is coupled to the second metal element, and is adjacent to the first radiation element and the second radiation element. The matching radiation element is coupled to the feeding radiation element. An antenna structure is formed by the feeding radiation element, the first radiation element, the second radiation element, the third radiation element, and the matching radiation element. A sensing pad is formed by the second metal element and the third radiation element.

In some embodiments, the electronic device further includes a system ground plane, a conductive gel layer, an isolation gel layer, and a dielectric substrate. The system ground plane provides the ground voltage. The conductive gel layer is configured to attach the first metal element to the system ground plane. The isolation gel layer is configured to attach the second metal element to the system ground plane. The feeding radiation element, the first radiation element, the second radiation element, the third radiation element, and the matching radiation element are disposed on the same surface of the dielectric substrate.

In some embodiments, the combination of the feeding radiate element, the first radiation element, and the second radiation element substantially has a T-shape.

In some embodiments, the third radiation element substantially has a U-shape.

In some embodiments, the second metal element substantially has an L-shape with a hollow region.

In some embodiments, the antenna structure covers a first frequency band, a second frequency band, and a third frequency band. The first frequency band is from 704 MHz to 960 MHz. The second frequency band is from 1710 MHz to 2170 MHz. The third frequency band is from 2300 MHz to 2700 MHz.

In some embodiments, the third radiation element includes a connection portion, a first extension portion, and a second extension portion. The connection portion is coupled between the first extension portion and the second extension portion. The first extension portion is adjacent to the first radiation element and the second radiation element. The connection portion and the second extension portion are coupled to the second metal element.

In some embodiments, the total length of the connection portion and the first extension portion of the third radiation element is substantially equal to 0.25 wavelength of the first frequency band.

In some embodiments, the total length of the feeding radiation element and the first radiation element is substantially equal to 0.25 wavelength of the second frequency band.

In some embodiments, the total length of the feeding radiation element and the second radiation element is substantially equal to 0.25 wavelength of the third frequency band.

DETAILED DESCRIPTION OF THE INVENTION

In order to illustrate the purposes, features and advantages of the invention, the embodiments and figures of the invention are shown in detail as follows.

FIG. 1is a top view of an electronic device100according to an embodiment of the invention. For example, the electronic device100may be applied to a smart phone, a tablet computer, or a notebook computer. As shown inFIG. 1, the electronic device100at least includes a first metal element110, a second metal element120, a feeding radiation element130, a first radiation element140, a second radiation element150, a third radiation element160, and a matching radiation element170. The feeding radiation element130, the first radiation element140, the second radiation element150, the third radiation element160, and the matching radiation element170may all be made of metal materials, such as copper, silver, aluminum, iron, or their alloys. It should be understood that the electronic device100may further include other components, such as a display device, a speaker, a touch control module, a power supply module, and a housing, although they are not displayed inFIG. 1.

For example, both of the first metal element110and the second metal element120may be made of copper foils. The first metal element110may substantially have a rectangular shape or a square shape. The first metal element110is coupled to a ground voltage VSS. The second metal element120may substantially have an L-shape with a hollow region125. The hollow region125may be a rectangular non-metal region. The second metal element120is completely separated from the first metal element110. In other words, a separate gap GS1may be formed between the second metal element120and the first metal element110, such that the second metal element120can be electrically isolated from the first metal element110.

FIG. 2is a partial sectional view of the electronic device100according to an embodiment of the invention. In the embodiment ofFIG. 2, the electronic device100further includes a system ground plane180and a conductive gel layer191. The system ground plane180can provide the ground voltage VSS. The conductive gel layer191may be made of a conductive material. The conductive gel layer191is configured to attach the first metal element110to the system ground plane180, such that the first metal element110is considered as an extension grounding portion of the system ground plane180.

FIG. 3is a partial sectional view of the electronic device100according to an embodiment of the invention. In the embodiment ofFIG. 3, the electronic device100further includes a system ground plane180and an isolation gel layer192. The system ground plane180can provide the ground voltage VSS. The isolation gel layer192may be made of a nonconductive material. The isolation gel layer192is configured to attach the second metal element120to the system ground plane180, such that the second metal element120is floating and ungrounded. However, the invention is not limited thereto. In alternative embodiments, adjustments are made and the second metal element120is partially coupled to the system ground plane180, without affecting the performance of the invention.

The feeding radiation element130may substantially have a straight-line shape. Specifically, the feeding radiation element130has a first end131and a second end132. A positive electrode of a signal source199is coupled to the first end131of the feeding radiation element130, and a negative electrode of the signal source199is coupled to the first metal element110. In some embodiments, the signal source199is an RF (Radio Frequency) module. The positive electrode of the signal source199may be further coupled through a central conductive line of a coaxial cable to the feeding radiation element130. The negative electrode of the signal source199may be further coupled through a conductive housing of the coaxial cable to the first metal element110.

The first radiation element140may substantially have a straight-line shape, which may be substantially perpendicular to the feeding radiation element130. Specifically, the first radiation element140has a first end141and a second end142. The first end141of the first radiation element140is coupled to the second end132of the feeding radiation element130. The second end142of the first radiation element140is an open end.

The second radiation element150may substantially have a straight-line shape, which may be substantially perpendicular to the feeding radiation element130. Specifically, the second radiation element150has a first end151and a second end152. The first end151of the second radiation element150is coupled to the second end132of the feeding radiation element130. The second end152of the second radiation element150is an open end. The second end152of the second radiation element150and the second end142of the first radiation element140may substantially extend in opposite directions. In some embodiments, the combination of the feeding radiate element130, the first radiation element140, and the second radiation element150substantially has a T-shape.

The third radiation element160may substantially have a variable-width U-shape. Specifically, the third radiation element160includes a connection portion164, a first extension portion165, and a second extension portion166. The connection portion164is coupled between the first extension portion165and the second extension portion166. The first extension portion165and the second extension portion166may be substantially parallel to each other. The length of the first extension portion165may be longer than the length of the second extension portion166. The width W1of the connection portion164may be larger than the width W2of the first extension portion165, and may also be larger than the width W3of the second extension portion166. The first extension portion165of the third radiation element160is adjacent to the first radiation element140and the second radiation element150. A coupling gap GC1may be formed between the first extension portion165and each of the first radiation element140and the second radiation element150. Both of the connection portion164and the second extension portion166of the third radiation element160are coupled to the second metal element120. In some embodiments, the feeding radiation element130, the first radiation element140, the second radiation element150, and the matching radiation element170may all be positioned between the first extension portion165and the second extension portion166of the third radiation element160.

The matching radiation element170may substantially have a straight-line shape, which may be substantially parallel to the second radiation element150. Specifically, the matching radiation element170has a first end171and a second end172. The first end171of the matching radiation element170is coupled to the first end131of the feeding radiation element130. The second end172of the matching radiation element170is an open end, which is adjacent to the connection portion164of the third radiation element160. The second end172of the matching radiation element170and the second end152of the second radiation element150may substantially extend in the same direction. It should be noted that the term “adjacent” or “close” over the disclosure means that the distance (spacing) between two corresponding elements is smaller than a predetermined distance (e.g., 10 mm or shorter), but often does not mean that the two corresponding elements directly touch each other (i.e., the aforementioned distance/spacing therebetween is reduced to 0).

In a preferred embodiment, an antenna structure is formed by the feeding radiation element130, the first radiation element140, the second radiation element150, the third radiation element160, and the matching radiation element170. In addition, a sensing pad is formed by the second metal element120and the third radiation element160. Thus, the electronic device100can have both functions of proximity detection and signal transmission, and it is considered as a hybrid antenna. Since the antenna structure is well integrated with the sensing pad, the total size of the electronic device100is significantly reduced.

FIG. 4is a diagram of radiation efficiency of the antenna structure of the electronic device100according to an embodiment of the invention. The horizontal axis represents operation frequency (MHz), and the vertical axis represents radiation efficiency (dB). As shown inFIG. 4, a first curve CC1represents the operation characteristic of the electronic device100when the antenna structure has not been integrated with the sensing pad, and a second curve CC2represents the operation characteristic of the electronic device100when the antenna structure has been integrated with the sensing pad. According to the measurement ofFIG. 4, the incorporation of the sensing pad does not negatively affect the radiation performance of the antenna structure so much. Furthermore, the antenna structure of the electronic device100can cover a first frequency band FB1, a second frequency band FB2, and a third frequency band FB3. The first frequency band FB1may be from 704 MHz to 960 MHz. The second frequency band FB2may be from 1710 MHz to 2170 MHz. The third frequency band FB3may be from 2300 MHz to 2700 MHz. Thus, the antenna structure of the electronic device100can support at least the wideband operation of LTE (Long Term Evolution).

In some embodiments, the operation principles of the electronic device100are described as follows. The connection portion164and the first extension portion165of the third radiation element160are excited by the feeding radiation element130, the first radiation element140, and the third radiation element150using a coupling mechanism, so as to generate the first frequency band FB1. The feeding radiation element130and the first radiation element140are excited to generate the second frequency band FB2. The feeding radiation element130and the second radiation element150are excited to generate the third frequency band FB3. The matching radiation element170is configured to fine-tune the impedance matching of the first frequency band FB1, the second frequency band FB2, and the third frequency band FB3, thereby increasing the total operation bandwidth of the antenna structure. In addition, when a human body is close to the electronic device100, a virtual capacitor is formed between the human body and the sensing pad composed of the second metal element120and the third radiation element160. By analyzing the capacitance of the virtual capacitor, the electronic device100can estimate the distance to the human body, so as to control the RF power relative to the antenna structure and reduce the corresponding SAR (Specific Absorption Rate).

In some embodiments, the element sizes of the electronic device100are described as follows. The total length L1of the connection portion164and the first extension portion165of the third radiation element160may be substantially equal to 0.25 wavelength (λ/4) of the first frequency band FB1of the antenna structure. The total length L2of the feeding radiation element130and the first radiation element140may be substantially equal to 0.25 wavelength (λ/4) of the second frequency band FB2of the antenna structure. The total length L3of the feeding radiation element130and the second radiation element150may be substantially equal to 0.25 wavelength (λ/4) of the third frequency band FB3of the antenna structure. In the third radiation element160, the width W1of the connection portion164may be at least 5 times the width W2of the first extension portion165, and may also be at least 5 times the width W3of the second extension portion166. The length L4of the matching radiation element170may be longer than the total length L2of the feeding radiation element130and the first radiation element140, and may also be longer the total length L3of the feeding radiation element130and the second radiation element150. The width of the coupling gap GC1may be from 0.5 mm to 2 mm. The width of the separate gap GS1may be from 0.5 mm to 10 mm. The above ranges of element sizes are calculated and obtained according to many experiment results, and they help to optimize the operation bandwidth and impedance matching of the antenna structure of the electronic device100, and to maximize the detectable distance of the sensing pad of the electronic device100.

FIG. 5is a top view of an electronic device500according to another embodiment of the invention.FIG. 5is similar toFIG. 1. In the embodiment ofFIG. 5, the electronic device500further includes a system ground plane580, a dielectric substrate595, and a proximity sensor598. The dielectric substrate595may be an FR4(Flame Retardant4) substrate, a PCB (Printed Circuit Board), or an FCB (Flexible Circuit Board). The feeding radiation element130, the first radiation element140, the second radiation element150, the third radiation element160, and the matching radiation element170may all be disposed on the same surface E1of the dielectric substrate595. The first metal element110and the second metal element120may partially extend onto the surface E1of the dielectric substrate595. The proximity sensor598may be coupled to any position on the sensing pad composed of the second metal element120and the third radiation element160, such as any end of the second metal element120. As mentioned above, the first metal element110may be electrically connected to the system ground plane580, and the second metal element120may be separated from the first metal element110and not electrically connected to the system ground plane580. It should be noted since the second metal element120has the hollow portion125, such a design can significantly reduce the undesired capacitance between the second metal element120and the system ground plane580, thereby effectively increasing the detectable distance of the sensing pad. According to practical measurements, if the second metal element120does not have any hollow portion125(i.e., like a complete rectangular shape), the detectable distance of the sensing pad of the electronic device500may be only about 5 mm, but if the second metal element120has the hollow portion125(i.e., like an L-shape), the detectable distance of the sensing pad of the electronic device500may be increased to about 15 mm and improved by about 200%.

For example, the proposed electronic device100(or500) may be applied to a convertible mobile device600which includes an upper cover housing611, a display frame612, a keyboard frame613, a base housing614, and a hinge element615. By using the hinge element615, the convertible mobile device600can operate in a notebook mode or a tablet mode. It should be understood that the upper cover housing611, the display frame612, the keyboard frame613, the base housing614are equivalent to the so-called “A-component”, “B-component”, “C-component” and “D-component” in the field of notebook computers. Specifically, the proposed electronic device100(or500) may be disposed in the internal space between the keyboard frame613and the base housing614.

FIG. 6is a view of the convertible mobile device600operating in the notebook mode according to an embodiment of the invention.FIG. 7is a view of the convertible mobile device600operating in the tablet mode according to an embodiment of the invention. The arrows inFIG. 6andFIG. 7represent the testing directions of SAR. It should be noted that since the sensing pad is integrated with the antenna structure of the electronic device100(or500), the sensing pad can maintain a sufficient detectable distance (e.g., 15 mm or longer), regardless of the notebook mode or the tablet mode of the convertible mobile device600. The convertible mobile device600including the electronic device100(or500) has higher probability of passing the SAR test limited by the law.

The invention proposes a novel electronic device for effectively integrating an antenna structure with a sensing pad. According to practical measurements, the invention not only improves the operation performance of the antenna structure but also increases the probability of passing the SAR test, and therefore it is suitable for application in a variety of small-size mobile communication devices.

Note that the above element sizes, element shapes, and frequency ranges are not limitations of the invention. An antenna designer can fine-tune these settings or values according to different requirements. It should be understood that the electronic device of the invention is not limited to the configurations ofFIGS. 1-7. The invention may merely include any one or more features of any one or more embodiments ofFIGS. 1-7. In other words, not all of the features displayed in the figures should be implemented in the electronic device of the invention.