Patent Application
20180366816
The disclosure generally relates to a communication device, and more particularly, to a communication device and an antenna system therein.
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 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, 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.
Wireless access points are indispensable elements that allow mobile devices in a room to connect to the internet at high speeds. However, since indoor environments have serious signal reflection and multipath fading, wireless access points should process signals in a variety of polarization directions and from a variety of transmission directions simultaneously. Accordingly, it has become a critical challenge for antenna designers to design a high-gain, multi-polarized antenna in the limited space of a wireless access point.
In an exemplary embodiment, the disclosure is directed to a communication device that includes an antenna system. The antenna system includes a first dual-polarized antenna, a second dual-polarized antenna, a first reflector, a second reflector, a first PIFA (Planar Inverted F Antenna), a second PIFA, a third PIFA, a first metal loop, a second metal loop, and a third metal loop. The first reflector is disposed adjacent to the first dual-polarized antenna. The second reflector is disposed adjacent to the second dual-polarized antenna. The first PIFA is at least partially formed by the first reflector. The second PIFA is at least partially formed by the first reflector and the second reflector. The third PIFA is at least partially formed by the second reflector. The first metal loop is disposed adjacent to the first PIFA. The first metal loop is floating and completely separated from the first PIFA. The second metal loop is disposed adjacent to the second PIFA. The second metal loop is floating and completely separated from the second PIFA. The third metal loop is disposed adjacent to the third PIFA. The third metal loop is floating and completely separated from the third PIFA.
The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
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.
Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . ”. The term “substantially” means the value is within an acceptable error range. One skilled in the art can solve the technical problem within a predetermined error range and achieve the proposed technical performance. Also, the term “couple” is intended to mean either an indirect or direct electrical connection. Accordingly, if one device is coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.
The first dual-polarized antenna 120 includes a first diamond-shaped dipole antenna element 121 and a second diamond-shaped dipole antenna element 122. The first diamond-shaped dipole antenna element 121 and the second diamond-shaped dipole antenna element 122 may be spaced apart to each other and perpendicular to each other, so as to achieve the dual-polarized characteristics. For example, if the first diamond-shaped dipole antenna element 121 has a first polarization direction and the second diamond-shaped dipole antenna element 122 has a second polarization direction, the first polarization direction may be perpendicular to the second polarization direction. The diamond-shape of each dipole antenna element is used to increase the high-frequency operation bandwidth of the antenna system 110. It should be noted that, in comparison to the first diamond-shaped dipole antenna element 121, two tip sharp corners of the second diamond-shaped dipole antenna element 122 are both cut and removed, so as to form two truncated tips 125 and 126. For example, the second diamond-shaped dipole antenna element 122 may include a positive radiation arm 123 and a negative radiation arm 124, and the positive radiation arm 123 and the negative radiation arm 124 may each have a substantially trapezoidal shape (a trapezoidal shape is generated by removing a tip sharp corner of a triangular shape). The positive radiation arm 123 and the negative radiation arm 124 are symmetrical. Such a design can reduce the coupling effect between the second diamond-shaped dipole antenna element 122 and the first PIFA 140 in the low-frequency band, thereby increasing the low-frequency isolation between adjacent PIFAs of the antenna system 110.
The first reflector 130 may have a frustum of a pyramidal shape (hollow structure) with a wide top opening and a narrow bottom plate. The wide top opening of the first reflector 130 faces the first dual-polarized antenna 120. Specifically, the wide top opening of the first reflector 130 has a relatively large rectangular shape, and the narrow bottom plate of the first reflector 130 has a relatively small rectangular shape. The first reflector 130 and the first dual-polarized antenna 120 are electrically isolated from each other. The first reflector 130 is configured to eliminate the back-side radiation of the first dual-polarized antenna 120 and to enhance the front-side radiation of the first dual-polarized antenna 120. Accordingly, the antenna gain of the first dual-polarized antenna 120 is increased. The invention is not limited to the above. In alternative embodiments, the first reflector 130 has a lidless triangular cylindrical shape or a lidless circular cylindrical shape (hollow structure), and its top opening still faces the first dual-polarized antenna 120, without affecting the performance of the invention.
The first PIFA 140 is at least partially formed by the first reflector 130. The first PIFA 140 includes a radiation element 141, a grounding element 142, and a feeding element 143. A slot 144 is formed between the radiation element 141 and the grounding element 142. The slot 144 has a varying width so as to increase the low-frequency operation bandwidth of the first PIFA 140. The radiation element 141 and the grounding element 142 of the first PIFA 140 may be a portion of a sidewall of the first reflector 130. The slot 144 may have a varying-width L-shape, and it can at least partially separate the radiation element 141 from the grounding element 142. Specifically, the narrowest portion 145 of the slot 144 is positioned at the middle of the slot 144. Based on the narrowest portion 145, the width of an upper portion of the slot 144 above the narrowest portion 145 gradually increases, and the width of a lower portion of the slot 144 below the narrowest portion 145 also gradually increases. The feeding element 143 may be a coaxial cable. The feeding element 143 extends across the narrowest portion 145 of the varying-width L-shape of the slot 144, and is further coupled to the radiation element 141, so as to excite the first PIFA 140. Such a design can improve the low-frequency impedance matching of the first PIFA 140.
In some embodiments, the first PIFA 140 covers a low-frequency band from 746 MHz to 894 MHz, and the first dual-polarized antenna 120 covers a high-frequency band from 1710 MHz to 2155 MHz. Therefore, the antenna system 110 of the exemplary embodiment of the present invention can support at least the multiband and wideband operation of LTE (Long Term Evolution) Band 13/Band 5/Band 4/Band 2. Furthermore, the multi-polarized property of the antenna system 110 can help to solve the problem of multipath fading in indoor environments.
In some embodiments, the element sizes of the antenna system 110 are as follows. The total length L2 of the first diamond-shaped dipole antenna element 121 is substantially equal to 0.5 wavelength (λ/2) of the central frequency of the aforementioned high-frequency band. The total length L2 of the second diamond-shaped dipole antenna element 122 is substantially equal to 0.5 wavelength (λ/2) of the central frequency of the aforementioned high-frequency band. The total length L3 of the slot 144 of the first PIFA 140 is substantially equal to 0.25 wavelength (λ/4) of the central frequency of the aforementioned low-frequency band. The width W1 of the open end of the slot 144 is substantially equal to the width of the narrowest portion 145 of the slot 144. The length from the open end of the slot 144 to the narrowest portion 145 is slightly longer than the length from the closed end of the slot 144 to the narrowest portion 145. In order to generate constructive interference, the distance D1 between the first reflector 130 and the first dual-polarized antenna 120 (or the second diamond-shaped dipole antenna element 122) is slightly longer than 0.25 wavelength (λ/4) of the central frequency of the aforementioned high-frequency band. The above element sizes are calculated according to many simulation results, and they are arranged for optimizing the gain of all PIFAs of the antenna system 110 and the isolation between the PIFAs. According to the practical measurement, after the two tip sharp corners of the second diamond-shaped dipole antenna element 122 are both cut and removed, the isolation between any two adjacent PIFAs of the antenna system 110 is increased from about 9.8 dB to about 11 dB. Such a design can significantly improve the radiation performance of the antenna system 110.
In some embodiments, the antenna system 110 further includes a second dual-polarized antenna 120-2, a second reflector 130-2, and a second PIFA 140-2. The second dual-polarized antenna 120-2 is disposed opposite to or adjacent to the first dual-polarized antenna 120. The second reflector 130-2 is configured to reflect the radiation energy from the second dual-polarized antenna 120-2. The second PIFA 140-2 is at least partially formed by the second reflector 130-2. The structures and functions of the second dual-polarized antenna 120-2, the second reflector 130-2, and the second PIFA 140-2 are the same as those of the first dual-polarized antenna 120, the first reflector 130, and the first PIFA 140, and the only difference is that they are arranged facing different directions.
In some embodiments, the antenna system 110 further includes a third dual-polarized antenna 120-3, a third reflector 130-3, and a third PIFA 140-3. The third dual-polarized antenna 120-3 is disposed opposite to or adjacent to the first dual-polarized antenna 120. The third reflector 130-3 is configured to reflect the radiation energy from the third dual-polarized antenna 120-3. The third PIFA 140-3 is at least partially formed by the third reflector 130-3. The structures and functions of the third dual-polarized antenna 120-3, the third reflector 130-3, and the third PIFA 140-3 are the same as those of the first dual-polarized antenna 120, the first reflector 130, and the first PIFA 140, and the only difference is that they are arranged facing different directions.
In some embodiments, the antenna system 110 further includes a fourth dual-polarized antenna 120-4, a fourth reflector 130-4, and a fourth PIFA 140-4. The fourth dual-polarized antenna 120-4 is disposed opposite to or adjacent to the first dual-polarized antenna 120. The fourth reflector 130-4 is configured to reflect the radiation energy from the fourth dual-polarized antenna 120-4. The fourth PIFA 140-4 is at least partially formed by the fourth reflector 130-4. The structures and functions of the fourth dual-polarized antenna 120-4, the fourth reflector 130-4, and the fourth PIFA 140-4 are the same as those of the first dual-polarized antenna 120, the first reflector 130, and the first PIFA 140, and the only difference is that they are arranged facing different directions.
In some embodiments, the communication device 100 further includes a metal elevating pillar 160 and a top reflective plate 170. The metal elevating pillar 160 is coupled to the first reflector 130, the second reflector 130-2, the third reflector 130-3, and the fourth reflector 130-4. The metal elevating pillar 160 may have a hollow structure for accommodating a variety of electronic circuit elements, such as a processor, an antenna switching module, and a matching circuit. The metal elevating pillar 160 is configured to support the antenna system 110. The top reflective plate 170 is also coupled to the first reflector 130, the second reflector 130-2, the third reflector 130-3, and the fourth reflector 130-4. The top reflective plate 170 is perpendicular to the first reflector 130, the second reflector 130-2, the third reflector 130-3, and the fourth reflector 130-4. The top reflective plate 170 is configured to reflect the radiation toward the zenith direction, so as to enhance the antenna gain of the antenna system 110. In alternative embodiments, the communication device 100 further includes a nonconductive antenna cover (radome) (not shown). The nonconductive antenna cover has a hollow structure (e.g., a hollow circular cylinder or a hollow square cylinder, which has a top lid but no bottom lid). The antenna system 110 and the top reflective plate 170 are both completely inside the nonconductive antenna cover. The nonconductive antenna cover is configured to protect the antenna system 110 from interference from the environment. For example, the nonconductive antenna cover may have waterproofing and sun-protection functions.
Please refer to
The first dual-polarized antenna 120 and the second dual-polarized antenna 120-2 each includes a first diamond-shaped dipole antenna element 121 and a second diamond-shaped dipole antenna element 122. It should be understood that the first dual-polarized antenna 120 and the second dual-polarized antenna 120-2 have the same structures but are arranged in different directions, and only the first dual-polarized antenna 120 is introduced herein as an example. The first diamond-shaped dipole antenna element 121 and the second diamond-shaped dipole antenna element 122 may be spaced apart to each other and perpendicular to each other. Two tip sharp corners of the second diamond-shaped dipole antenna element 122 are both cut and removed, so as to form two truncated tips 125 and 126. For example, the second diamond-shaped dipole antenna element 122 may include a positive radiation arm 123 and a negative radiation arm 124, and the positive radiation arm 123 and the negative radiation arm 124 may each have a substantially trapezoidal shape. The positive radiation arm 123 and the negative radiation arm 124 are symmetrical. It should be noted that as shown in
The first reflector 630 is disposed adjacent to the first dual-polarized antenna 120, and is configured to reflect the radiation energy from the first dual-polarized antenna 120. The second reflector 630-2 is disposed adjacent to the second dual-polarized antenna 120-2, and is configured to reflect the radiation energy from the second dual-polarized antenna 120-2. 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). The first reflector 630 and the second reflector 630-2 may each have a frustum of a pyramidal shape with a wide top opening and a narrow bottom plate. The wide top opening of the first reflector 630 faces the first dual-polarized antenna 120. For example, the wide top opening of the first reflector 630 may have a relatively large rectangular shape, and the narrow bottom plate of the first reflector 630 may have a relatively small rectangular shape, but it is not limited thereto. The first reflector 630 and the first dual-polarized antenna 120 are electrically isolated from each other. The wide top opening of the second reflector 630-2 faces the second dual-polarized antenna 120-2. For example, the wide top opening of the second reflector 630-2 may have a relatively large rectangular shape, and the narrow bottom plate of the second reflector 630-2 may have a relatively small rectangular shape, but it is not limited thereto. The second reflector 630-2 and the second dual-polarized antenna 120-2 are electrically isolated from each other. In some embodiments, the first reflector 630 and the second reflector 630-2 are symmetrical with respect to the central axis SLM1 of the antenna system 600.
The first PIFA 640 is at least partially formed by the first reflector 630. The second PIFA 640-2 is at least partially formed by a combination of the first reflector 630 and the second reflector 630-2. The third PIFA 640-3 is at least partially formed by the second reflector 630-2. The first PIFA 640 includes a radiation element 641, a grounding element 642, and a feeding element 643, and a slot 644 is formed between the radiation element 641 and the grounding element 642. It should be understood that the first PIFA 640, the second PIFA 640-2, and the third PIFA 640-3 have the same structures but are arranged in different directions, and only the first PIFA 640 is introduced herein as an example. The radiation element 641 and the grounding element 642 of the first PIFA 640 may be a portion of a sidewall of the first reflector 630. The slot 644 may have an equal-width L-shape, and it can at least partially separate the radiation element 641 from the grounding element 642. The feeding element 643 extends across the slot 644, and is further coupled to the radiation element 641. However, the invention is not limited to the above. In alternative embodiments, the slot 644 has a varying-width L-shape, and its details are similar to those described in the embodiments of
The first metal loop 150 is disposed adjacent to the first PIFA 640. The first metal loop 150 is floating, and is completely separated from the first PIFA 640. The second metal loop 150-2 is disposed adjacent to the second PIFA 640-2. The second metal loop 150-2 is floating, and is completely separated from the second PIFA 640-2. The third metal loop 150-3 is disposed adjacent to the third PIFA 640-3. The third metal loop 150-3 is floating, and is completely separated from the third PIFA 640-3. For example, the first metal loop 150, the second metal loop 150-2, and the third metal loop 150-3 may each have a hollow rectangular shape. It should be understood that the first metal loop 150, the second metal loop 150-2, and the third metal loop 150-3 have the same structures but are arranged in different directions, and only the first metal loop 150 is introduced herein as an example. The first PIFA 640 is positioned between the first metal loop 150 and the narrow bottom plate of the first reflector 630. A rectangular hollow portion 151 may be formed inside the first metal loop 150. In some embodiments, the first metal loop 150 and the third metal loop 150-3 are symmetrical with respect to the central axis SLM1 of the antenna system 600.
In some embodiments, the first PIFA 640, the second PIFA 640-2, and the third PIFA 640-3 can each cover a low-frequency band from 746 MHz to 894 MHz, and the first dual-polarized antenna 120 and the second dual-polarized antenna 120-2 can each cover a high-frequency band from 1710 MHz to 2155 MHz.
In some embodiments, the communication device 600 further includes a top reflective plate 670 and a bottom reflective plate 680. The top reflective plate 670 and the bottom reflective plate 680 are both coupled to the first reflector 630 and the second reflector 630-2. The top reflective plate 670 and the bottom reflective plate 680 are both perpendicular to the first reflector 630 and the second reflector 630-2. The top reflective plate 670 and the bottom reflective plate 680 are configured to enhance the antenna gain of the antenna system 610.
In some embodiments, the communication device 600 further includes an electronic-circuit metal box 660, a first additional reflector 681, and a second additional reflector 682. The electronic-circuit metal box 660 may have a hollow structure for accommodating a variety of electronic circuit elements, such as a processor, an antenna switching module, and a matching circuit. The electronic-circuit metal box 660 is disposed adjacent to the back side of the first reflector 630 and the back side of the second reflector 630-2. Alternatively, the electronic-circuit metal box 660 may be directly touch both the narrow bottom plate of the first reflector 630 and the narrow bottom plate of the second reflector 630-2. Such an arrangement of the electronic-circuit metal box 660 can free-up much of the circuit design area on a main PCB (Printed Circuit Board). The first additional reflector 681 and the second additional reflector 682 may each be implemented with its own respective rectangular metal plane. The first additional reflector 681 is coupled to the electronic-circuit metal box 660, and is disposed adjacent to the first PIFA 640. The first PIFA 640 may have a vertical projection on the first additional reflector 681, and the whole vertical projection of the first PIFA 640 may be inside the first additional reflector 681. The first additional reflector 681 is configured to eliminate the back-side radiation of the first PIFA 640 and to enhance the front-side radiation of the first PIFA 640. The second additional reflector 682 is coupled to the electronic-circuit metal box 660, and is disposed adjacent to the third PIFA 640-3. The third PIFA 640-3 may have a vertical projection on the second additional reflector 682, and the whole vertical projection of the third PIFA 640-3 may be inside the second additional reflector 682. The second additional reflector 682 is configured to eliminate the back-side radiation of the third PIFA 640-3 and to enhance the front-side radiation of the third PIFA 640-3. In some embodiments, the first additional reflector 681 and the second additional reflector 682 are symmetrical with respect to the central axis SLM1 of the antenna system 600.
In some embodiments, the antenna system 610 is a beam switching antenna assembly for selectively using any one of the first dual-polarized antenna 120 and the second dual-polarized antenna 120-2 and selectively using any adjacent two of the first PIFA 640, the second PIFA 640-2, and the third PIFA 640-3, so to perform signal reception and transmission. For example, the second PIFA 640-2 may be always enabled, either the first dual-polarized antenna 120 or the second dual-polarized antenna 120-2 may be enabled (the other one may be disabled), and either the first PIFA 640 or the third PIFA 640-3 may be enabled (the other one may be disabled).
In some embodiments, the element sizes of the antenna system 610 are as follows. The distance D3 between the first metal loop 150 and the first PIFA 640 (or between the second metal loop 150-2 and the second PIFA 640-2, or between the third metal loop 150-3 and the third PIFA 640-3) may be from 5 mm to 15 mm, such as 9.55 mm. The length of each rectangular hollow portion of the first metal loop 150, the second metal loop 150-2, and the third metal loop 150-3 may be from 0.25 to 0.5 wavelength (λ/4 to λ/2) of the central frequency of the low-frequency band of the antenna system 610. The angle θ1 between the first PIFA 640 and the electronic-circuit metal box 660 (or between the first PIFA 640 and the first additional reflector 681) may be from 20 to 40 degrees, such as 30 degrees. The angle θ2 between the third PIFA 640-3 and the electronic-circuit metal box 660 (or between the third PIFA 640-3 and the second additional reflector 682) may be from 20 to 40 degrees, such as 30 degrees. The angle θ3 between the first PIFA 640 and the third PIFA 640-3 may be smaller than 180 degrees. For example, the angle θ3 between the first PIFA 640 and the third PIFA 640-3 may be from 100 to 140 degrees. The average distance D4 between the first PIFA 640 and the first additional reflector 681 may be equal to 0.25 wavelength (λ/4) of the central frequency of the low-frequency band of the antenna system 610. The average distance D5 between the third PIFA 640-3 and the second additional reflector 682 may be equal to 0.25 wavelength (λ/4) of the central frequency of the low-frequency band of the antenna system 610. The above ranges of element sizes are calculated and obtained according to many experiment results, and they help to optimize the operation bandwidth, the radiation pattern, the antenna gain, and the impedance matching of the antenna system 610 of the communication device 600.
The communication device 600 of
The invention proposes a communication device whose antenna system has the advantages of high isolation and high antenna gain. The invention is suitable for application in a variety of indoor environments, so as to solve the problems of poor communication quality due to signal reflection and multipath fading in conventional designs.
Note that the above element sizes, element parameters, 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 communication device and antenna system of the invention are not limited to the configurations of
Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having the same name (but for use of the ordinal term) to distinguish the claim elements.
While the invention has been described by way of example and in terms of the preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 106120151 | Jun 2017 | TW | national |
This application is a Continuation-In-Part of application Ser. No. 15/691,640, filed on Aug. 30, 2017, which claims the priority of Taiwan Patent Application No. 106120151 filed on Jun. 16, 2017, and the entirety of which are incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15691640 | Aug 2017 | US |
| Child | 16053705 | US |
