Antenna system

An antenna system includes a first antenna element, a second antenna element, and a circuit region. The first antenna element includes a first nonconductive support element and a first main radiation element. The first main radiation element is disposed on the first nonconductive support element. The second antenna element includes a second nonconductive support element and a second main radiation element. The second main radiation element is disposed on the second nonconductive support element. The second main radiation element is at least partially perpendicular to the first main radiation element. The circuit region is positioned between the first antenna element and the second antenna element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of Taiwan Patent Application No. 109146593 filed on Dec. 29, 2020, the entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

Field of the Invention

The disclosure generally relates to an antenna system, and more particularly, it relates to an almost omnidirectional antenna system.

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 user demand, mobile devices can usually perform wireless communication functions. Some devices cover a large wireless communication area; these include mobile phones using 2G, 3G, 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, 2500 MHz, and 2700 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 elements for wireless communication. If an antenna used for signal reception and transmission has a radiation pattern with any null, it will negatively affect the communication quality of the mobile device. Accordingly, it has become a critical challenge for antenna designers to design an almost omnidirectional antenna system.

BRIEF SUMMARY OF THE INVENTION

In an exemplary embodiment, the disclosure is directed to an antenna system that includes a first antenna element, a second antenna element, and a circuit region. The first antenna element includes a first nonconductive support element and a first main radiation element. The first main radiation element is disposed on the first nonconductive support element. The second antenna element includes a second nonconductive support element and a second main radiation element. The second main radiation element is disposed on the second nonconductive support element. The second main radiation element is at least partially perpendicular to the first main radiation element. The circuit region is positioned between the first antenna element and the second antenna element.

In some embodiments, the first antenna element and the second antenna element cover a first frequency band, a second frequency band, and a third frequency band. The first frequency band is from 699 MHz to 960 MHz. The second frequency band is from 1710 MHz to 2200 MHz. The third frequency band is from 2300 MHz to 2690 MHz.

In some embodiments, the second frequency band includes a first frequency interval, a second frequency interval, and a third frequency interval. The first frequency interval is from 1710 MHz to 1800 MHz. The second frequency interval is from 1800 MHz to 2000 MHz. The third frequency interval is from 2000 MHz to 2200 MHz.

In some embodiments, the first antenna element further includes a first feeding radiation element, a first radiation element, a shorting element, a second radiation element, a third radiation element, and a fourth radiation element. The first feeding radiation element has a first feeding point. The first main radiation element is coupled to the first feeding radiation element. The first radiation element is coupled to the first feeding radiation element. The first radiation element is coupled through the shorting element to a ground voltage. The second radiation element is coupled to the first feeding radiation element. The third radiation element is coupled to the first feeding point. The fourth radiation element is coupled to the ground voltage. The fourth radiation element is adjacent to the third radiation element. The first feeding radiation element, the first radiation element, the shorting element, the second radiation element, the third radiation element, and the fourth radiation element are disposed on the first nonconductive support element.

In some embodiments, the first main radiation element further includes a terminal U-shaped bending portion.

In some embodiments, the total length of the first feeding radiation element and the first main radiation element is shorter than or equal to 0.25 wavelength of the first frequency band.

In some embodiments, the first radiation element has a variable-width meandering shape.

In some embodiments, each of the second radiation element, the third radiation element, and the fourth radiation element substantially has an L-shape.

In some embodiments, the length of the first radiation element is shorter than or equal to 0.25 wavelength of the first frequency interval.

In some embodiments, the total length of the first feeding radiation element and the second radiation element is shorter than or equal to 0.25 wavelength of the second frequency interval.

In some embodiments, the length of the third radiation element is shorter than or equal to 0.25 wavelength of the third frequency interval.

In some embodiments, the length of the fourth radiation element is shorter than or equal to 0.25 wavelength of the third frequency band.

In some embodiments, the first antenna element further includes a first matching element and a second matching element. The first matching element and the second matching element are coupled to the first radiation element, and substantially extend away from each other. The first matching element and the second matching element are disposed on the first nonconductive support element.

In some embodiments, second antenna element further includes a second feeding radiation element, a fifth radiation element, a sixth radiation element, a seventh radiation element, and an eighth radiation element. The second feeding radiation element has a second feeding point. The second main radiation element is coupled through the fifth radiation element to the second feeding radiation element. The fifth radiation element is coupled through the sixth radiation element to the ground voltage. The seventh radiation element is coupled to the second feeding radiation element. The eighth radiation element is coupled to the ground voltage. The second feeding radiation element, the fifth radiation element, the sixth radiation element, the seventh radiation element, and the eighth radiation element are disposed on the second nonconductive support element.

In some embodiments, the fifth radiation element and the second feeding radiation element are substantially perpendicular to each other.

In some embodiments, the total length of the second feeding radiation element, the fifth radiation element, and the second main radiation element is shorter than or equal to 0.25 wavelength of the first frequency band.

In some embodiments, each of the sixth radiation element, the seventh radiation element, and the eighth radiation element substantially has an L-shape.

In some embodiments, the total length of the second feeding radiation element, the fifth radiation element, and the sixth radiation element is shorter than or equal to 0.5 wavelength of the first frequency interval.

In some embodiments, the total length of the second feeding radiation element and the seventh radiation element is shorter than or equal to 0.25 wavelength of the second frequency interval or the third frequency interval.

In some embodiments, the length of the eighth radiation element is shorter than or 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 below.

FIG. 1is a diagram of an antenna system100according to an embodiment of the invention. The antenna system100may be applied to a mobile device, such as a phone, a tablet computer, or a notebook computer. As shown inFIG. 1, the antenna system100includes a first antenna element200, a second antenna element300, and a circuit region400. The first antenna element200includes a first main radiation element220and a first nonconductive support element299. The first main radiation element220is disposed on the first nonconductive support element299. The second antenna element300includes a second main radiation element330and a second nonconductive support element399. The second main radiation element330is disposed on the second nonconductive support element399. The shapes of the first main radiation element220and the second main radiation element330are not limited in the invention, and they may both be made of metal materials, such as silver, copper, aluminum, iron, or their alloys. The circuit region400is positioned between the first antenna element200and the second antenna element300. The circuit region400may be coupled to a system ground plane (not shown). The circuit region400can accommodate one or more circuit components, such as a processor, a memory device, and/or a battery, although they are not displayed inFIG. 1. It should be noted that the second main radiation element330of the second antenna element300is at least partially perpendicular to the first main radiation element220of the first antenna element200. For example, the angle θ between a portion of the second main radiation element330and the first main radiation element220may be from 45 to 135 degrees, or may be from 60 to 120 degrees, such as about 90 degrees. According to practical measurements, such an at least partially orthogonal design can effectively suppress all of the nulls of the antenna system100, and therefore the antenna system100can provide an almost omnidirectional radiation pattern.

In some embodiments, both the first antenna element200and the second antenna element300of the antenna system100can cover a first frequency band, a second frequency band, and a third frequency band. For example, the first frequency band may be from 699 MHz to 960 MHz, the second frequency band may be from 1710 MHz to 2200 MHz, and the third frequency band may be from 2300 MHz to 2690 MHz. Specifically, the second frequency band may include a first frequency interval from 1710 MHz to 1800 MHz, a second frequency interval from 1800 MHz to 2000 MHz, and a third frequency interval from 2000 MHz to 2200 MHz. Therefore, the antenna system100can support at least the wideband operations of LTE (Long Term Evolution) and the next 5G (5th Generation Wireless System) communication.

The following embodiments will introduce the detail structures of the first antenna element200and the second antenna element300. It should be understood that these figures and descriptions are merely exemplary, rather than limitations of the invention.

FIG. 2is a perspective view of the first antenna element200according to an embodiment of the invention. In the embodiment ofFIG. 2, the first antenna element200includes a first feeding radiation element210, a first main radiation element220, a first radiation element230, a shorting element240, a second radiation element250, a third radiation element260, a fourth radiation element270, and a first nonconductive support element299. The first feeding radiation element210, the first main radiation element220, the first radiation element230, the shorting element240, the second radiation element250, the third radiation element260, and the fourth radiation element270may all be made of metal materials, and they may all be disposed on the first nonconductive support element299. In addition, the first nonconductive support element299has a first surface E1and a second surface E2which are substantially perpendicular to each other.

The first feeding radiation element210may substantially have a straight-line shape, which may be positioned on the first surface E1of the first nonconductive support element299. Specifically, the first feeding radiation element210has a first end211and a second end212. A first feeding point FP1is positioned at the first end211of the first feeding radiation element210. The first feeding point FP1may be further coupled to a signal source (not shown). For example, the signal source may be an RF (Radio Frequency) module for exciting both the first antenna element200and the second antenna element300.

The first main radiation element220may substantially have a meandering shape, which may extend from the second surface E2onto the first surface E1of the first nonconductive support element299. Specifically, the first main radiation element220has a first end221and a second end222. The first end221of the first main radiation element220is coupled to the second end212of the first feeding radiation element210. The second end222of the first main radiation element220is an open end. In some embodiments, the first main radiation element220further includes a terminal U-shaped bending portion225, which is adjacent to the second end222of the first main radiation element220. It should be noted that the term “adjacent” or “close” over the disclosure means that the distance (spacing) between two corresponding elements is shorter than a predetermined distance (e.g., 5 mm or shorter), or means that the two corresponding elements are touching each other directly (i.e., the aforementioned distance/spacing therebetween is reduced to 0).

The first radiation element230may substantially have a variable-width meandering shape (with a widening portion235), which may be positioned on the first surface E1of the first nonconductive support element299. Specifically, the first radiation element230has a first end231and a second end232. The first end231of the first radiation element230is coupled to a first connection point CP1on the first feeding radiation element210. The second end232of the first radiation element230is an open end.

The shorting element240may substantially have a straight-line shape, which may be positioned on the first surface E1of the first nonconductive support element299. The widening portion235of the first radiation element230is coupled through the shorting element240to a ground voltage VSS (e.g., 0V).

The second radiation element250may substantially have an L-shape, which may be positioned on the first surface E1of the first nonconductive support element299. Specifically, the second radiation element250has a first end251and a second end252. The first end251of the second radiation element250is coupled to the second end212of the first feeding radiation element210. The second end252of the second radiation element250is an open end.

The third radiation element260may substantially have an L-shape, which may be positioned on the first surface E1of the first nonconductive support element299. Specifically, the third radiation element260has a first end261and a second end262. The first end261of the third radiation element260is coupled to the first feeding point FP1. The second end262of the third radiation element260is an open end. For example, the second end262of the third radiation element260and the second end232of the first radiation element230may extend in the same direction.

The fourth radiation element270may substantially have an L-shape, which may be positioned on the first surface E1of the first nonconductive support element299. Specifically, the fourth radiation element270has a first end271and a second end272. The first end271of the fourth radiation element270is coupled to the ground voltage VSS. The second end272of the fourth radiation element270is an open end. For example, the second end272of the fourth radiation element270and the second end262of the third radiation element260may extend in opposite directions and away from each other. The fourth radiation element270is adjacent to but separate from the third radiation element260. A coupling gap GC1may be formed between the fourth radiation element270and the third radiation element260.

In some embodiments, the first antenna element200further includes a first matching element280and a second matching element290, which may both be made of metal materials. The first matching element280may substantially have a bending straight-line shape, which may extend from the first surface E1onto the second surface E2of the first nonconductive support element299. Specifically, the first matching element280has a first end281and a second end282. The first end281of the first matching element280is coupled to a second connection point CP2on the first radiation element230. The second end282of the first matching element280is an open end. The second matching element290may substantially have a straight-line shape, which may be positioned on the first surface E1of the first nonconductive support element299. Specifically, the second matching element290has a first end291and a second end292. The first end291of the second matching element290is coupled to a third connection point CP3on the first radiation element230. The second end292of the second matching element290is an open end. For example, the second end292of the second matching element290and the second end282of the first matching element280may extend away from each other. In addition, a crisscross shape may be formed by the first radiation element230, the first matching element280, and the second matching element290. It should be understood that the first matching element280and the second matching element290are optional components, which are removable in other embodiments.

With respect to the antenna theory of the first antenna element200, the first feeding radiation element210and the first main radiation element220are excited to generate the aforementioned first frequency band. The first feeding radiation element210, the first radiation element230, the second radiation element250, and the third radiation element260are excited to generate the aforementioned second frequency band. The fourth radiation element270is excited to generate the aforementioned third frequency band. Furthermore, the incorporations of the shorting element240, the first matching element280, and the second matching element290can help to fine-tune the impedance matching of the first antenna element200.

In some embodiments, the element sizes of the first antenna element200are described as follows. The total length L1of the first feeding radiation element210and the first main radiation element220may be shorter than or equal to 0.25 wavelength (λ/4) of the first frequency band of the antenna system100. The length L2of the first radiation element230may be shorter than or equal to 0.25 wavelength (λ/4) of the first frequency interval of the antenna system100. The total length L3of the first feeding radiation element210and the second radiation element250may be shorter than or equal to 0.25 wavelength (λ/4) of the second frequency interval of the antenna system100. The length L4of the third radiation element260may be shorter than or equal to 0.25 wavelength (λ/4) of the third frequency interval of the antenna system100. The length L5of the fourth radiation element270may be shorter than or equal to 0.25 wavelength (λ/4) of the third frequency band of the antenna system100. The width of the coupling gap GC1may be shorter than 4 mm. The above ranges of element sizes and element parameters are calculated and obtained according to many experiment results, and they help to optimize the operation bandwidth and the impedance matching of the first antenna element200.

FIG. 3is a perspective view of the second antenna element300according to an embodiment of the invention. In the embodiment ofFIG. 3, the second antenna element300includes a second feeding radiation element310, a fifth radiation element320, a second main radiation element330, a sixth radiation element340, a seventh radiation element350, an eighth radiation element360, and a second nonconductive support element399. The second feeding radiation element310, the fifth radiation element320, the second main radiation element330, the sixth radiation element340, the seventh radiation element350, and the eighth radiation element360may all be made of metal materials, and they may all be disposed on the second nonconductive support element399. In addition, the second nonconductive support element399has a third surface E3and a fourth surface E4which are substantially perpendicular to each other.

The second feeding radiation element310may substantially have a straight-line shape, which may be positioned on the third surface E3of the second nonconductive support element399. Specifically, the second feeding radiation element310has a first end311and a second end312. A second feeding point FP2is positioned at the first end311of the second feeding radiation element310. The second feeding point FP2may be further coupled to the aforementioned signal source.

The fifth radiation element320may substantially have a straight-line shape, which may be positioned on the third surface E3of the second nonconductive support element399. The fifth radiation element320may be substantially perpendicular to the second feeding radiation element310. Specifically, the fifth radiation element320has a first end321and a second end322. The first end321of the fifth radiation element320is coupled to the second end312of the second feeding radiation element310.

The second main radiation element330may substantially has a meandering shape, which may extend from the third surface E3onto the fourth surface E4of the second nonconductive support element399. Specifically, the second main radiation element330has a first end331and a second end332. The first end331of the second main radiation element330is coupled to the second end322of the fifth radiation element320. The second end332of the second main radiation element330is an open end. That is, the second main radiation element330is coupled through the fifth radiation element320to the second feeding radiation element310. In some embodiments, the second main radiation element330further includes a terminal extension bending portion335, which is adjacent to the second end332of the second main radiation element330. The terminal extension bending portion335of the second main radiation element330may be substantially perpendicular to the aforementioned first main radiation element220. In some embodiments, the angle between the terminal extension bending portion335of the second main radiation element330and the first main radiation element220may be from 45 to 135 degrees, or may be from 60 to 120 degrees, such as about 90 degrees.

The sixth radiation element340may substantially have an L-shape, which may be positioned on the third surface E3of the second nonconductive support element399. Specifically, the sixth radiation element340has a first end341and a second end342. The first end341of the sixth radiation element340is coupled to the ground voltage VSS. The second end342of the sixth radiation element340is coupled to the second end322of the fifth radiation element320. That is, the fifth radiation element320is coupled through the sixth radiation element340to the ground voltage VSS. In some embodiments, the first end341of the sixth radiation element340is adjacent to the second feeding point FP2, such that a loop structure is almost formed by the second feeding radiation element310, the fifth radiation element320, and the sixth radiation element340.

The seventh radiation element350may substantially have an L-shape, which may be positioned on the third surface E3of the second nonconductive support element399. Specifically, the seventh radiation element350has a first end351and a second end352. The first end351of the seventh radiation element350is coupled to the second end312of the second feeding radiation element310. The second end352of the seventh radiation element350is an open end. For example, the second end352of the seventh radiation element350may extend toward the second main radiation element330.

The eighth radiation element360may substantially have an L-shape, which may be positioned on the third surface E3of the second nonconductive support element399. Specifically, the eighth radiation element360has a first end361and a second end362. The first end361of the eighth radiation element360is coupled to the first end341of the sixth radiation element340and the ground voltage VSS. The second end362of the eighth radiation element360is an open end. For example, the second end362of the eighth radiation element360and the second end352of the seventh radiation element350may substantially extend in orthogonal directions.

With respect to the antenna theory of the second antenna element300, the second feeding radiation element310, the fifth radiation element320, and the second main radiation element330are excited to generate the aforementioned first frequency band. The second feeding radiation element310, the fifth radiation element320, the sixth radiation element340, and the seventh radiation element350are excited to generate the aforementioned second frequency band. The eighth radiation element360is excited to generate the aforementioned third frequency band.

In some embodiments, the element sizes of the second antenna element300are described as follows. The total length L6of the second feeding radiation element310, the fifth radiation element320, and the second main radiation element330may be shorter than or equal to 0.25 wavelength (λ/4) of the first frequency band of the antenna system100. The total length L7of the second feeding radiation element310, the fifth radiation element320, and the sixth radiation element340may be shorter than or equal to 0.5 wavelength (λ/2) of the first frequency interval of the antenna system100. The total length L8of the second feeding radiation element310and the seventh radiation element350may be shorter than or equal to 0.25 wavelength (λ/4) of the second frequency interval or the third frequency interval of the antenna system100. The length L9of the eighth radiation element360may be shorter than or equal to 0.25 wavelength (λ/4) of the third frequency band of the antenna system100. The distance D1between the first end341of the sixth radiation element340and the second feeding point FP2may be from 0.5 mm to 1.5 mm. The distance D2between the second end352of the seventh radiation element350and the second main radiation element330may be from 3 mm to 4 mm. The above ranges of element sizes and element parameters are calculated and obtained according to many experiment results, and they help to optimize the operation bandwidth and the impedance matching of the second antenna element300.

FIG. 4is a radiation pattern of a conventional antenna system. As shown inFIG. 4, the radiation pattern of the conventional antenna system usually has a non-ideal null (indicated by a dash-line box410), and thus the whole communication quality is degraded.

FIG. 5is a radiation pattern of the antenna system100according to an embodiment of the invention. According to the measurement ofFIG. 5, if the second main radiation element330of the second antenna element300is designed to be at least partially perpendicular to the first main radiation element220of the first antenna element200, the null of the antenna system100will be effectively eliminated (indicated by a dash-line box510). Therefore, the whole communication quality is significantly improved.

The invention proposes a novel antenna system. In comparison to the conventional technology, the proposed antenna system of the invention can almost eliminate all nulls and provide an almost omnidirectional radiation pattern, and therefore it is suitable for application in a variety of 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 antenna system of the invention is not limited to the configurations ofFIGS. 1-5. The invention may merely include any one or more features of any one or more embodiments ofFIGS. 1-5. In other words, not all of the features displayed in the figures should be implemented in the antenna system of the invention.