Patent Grant
9160075
1. Field of Invention
The subject application relates to a multi-band antenna. More particularly, the subject application relates to a multi-band antenna for a portable communication device.
2. Description of Related Art
With various exterior designs of portable communication devices, portable communication devices having metal frames have become popular. Generally, in a design of an antenna for a portable communication device having a metal frame, the metal frame is cut into a plurality of discontinuous metal structures, so that the antenna can radiate radio frequency (RF) signals.
A conventional portable communication device utilizes a planar inverted-F antenna (PIFA) and a discontinuous metal frame to construct a multi-band antenna, such that requirements of lightness, thinness, short length, and small size of the portable communication device may be realized. However, constraints in the design of a multi-band antenna are encountered due to the spacing among an antenna main body, a system ground plane and the metal frame, increasing the difficulty of design. Moreover, this discontinuous metal structure may cause a frequency shift and radiation efficiency decline of resonant modes, thereby negatively affecting the communication quality of the portable communication device.
In view of foregoing, there is an urgent need in the related field to provide a solution.
In one or more various aspects, the subject application is directed to a multi-band antenna for a portable communication device. The portable communication device includes a first housing, a second housing and a substrate. The multi-band antenna includes a feeding portion, a system ground plane, a metal ring, a resonant cavity, a first and a second radiating portion. The system ground plane is disposed on the substrate. The metal ring is connected to the first housing, and forms a space with the first housing to accommodate the substrate, in which the metal ring is electrically coupled to the system ground plane through a plurality of ground ends. The resonant cavity is formed between the system ground plane and the metal ring, and to generate a first resonant mode with the metal ring. The first and the second radiating portion are disposed on the second housing, for generating a second and a third resonant mode, respectively.
In accordance with an embodiment of the present disclosure, the foregoing multi-band antenna further includes a first conductive portion and a second conductive portion. The first conductive portion is disposed on the second housing, and the first radiating portion is electrically coupled to one side of the first conductive portion. The second radiating portion is electrically coupled to another side of the first conductive portion, and the first conductive portion is electrically coupled to the feeding portion when the first housing and the second housing are connected to each other. The second conductive portion is disposed on the second housing and electrically coupled to the first conductive portion, and the second conductive portion is electrically coupled to the metal ring when the first housing and the second housing are connected to each other. Furthermore, when the first housing and the second housing are connected to each other, a projection of the first conductive portion with respect to a normalized view of the substrate at least partially overlaps the resonant cavity.
In accordance with an embodiment of the present disclosure, a transverse dimension of the metal ring, a longitudinal dimension of the metal ring and a first gap width of the resonant cavity are used to control at least one of a resonant frequency of the first resonant mode, a bandwidth of the first resonant mode and a return loss of the first resonant mode.
In accordance with an embodiment of the present disclosure, the foregoing multi-band antenna further includes a first metal element disposed in the resonant cavity. An electrical length of the first metal element is used to adjust a current path and control a resonant frequency of the first resonant mode.
In accordance with an embodiment of the present disclosure, when an electrical length of the second radiating portion is longer than an electrical length of the first radiating portion, a resonant frequency of the third resonant mode is smaller than a resonant frequency of the second resonant mode.
In accordance with an embodiment of the present disclosure, when an electrical length of the second radiating portion is shorter than an electrical length of the first radiating portion, a resonant frequency of the third resonant mode is larger than a resonant frequency of the second resonant mode.
In accordance with an embodiment of the present disclosure, the foregoing multi-band antenna further comprises a second metal element and a third metal element, both of which are disposed on the second housing and electrically coupled to the first conductive portion. An electrical length of the second metal element is used to adjust an impedance matching of the first radiating portion, and an electrical length of the third metal element is used to adjust an impedance matching of the second radiating portion.
In accordance with an embodiment of the present disclosure, the feeding portion is disposed on the substrate and comprises a metal spring. The metal spring is electrically coupled to the first conductive portion when the first housing and the second housing are connected to each other.
In accordance with an embodiment of the present disclosure, the first conductive portion, the second conductive portion, the first radiating portion and the second radiating portion are disposed on a first surface of the second housing.
In accordance with an embodiment of the present disclosure, the foregoing multi-band antenna further includes a third conductive portion disposed on the second housing. The third conductive portion is electrically coupled to the first conductive portion and penetrates through the first surface and a second surface of the second housing. When the first housing and the second housing are connected to each other, the feeding portion is electrically coupled to the first conductive portion via the third conductive portion.
In accordance with an embodiment of the present disclosure, the first conductive portion, the second conductive portion, the first radiating and the second radiating are disposed on a second surface of the second housing.
In accordance with an embodiment of the present disclosure, the metal ring is a continuous metal structure.
In summary, through implementing the disclosure of the foregoing multi-band antenna structures, the bandwidth of resonant modes, antenna gain and performance of the portable communication device can be improved, and interference with the antenna caused by outside objects can be reduced. Therefore, high communication quality of the portable communication device is ensured.
The subject application can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows:
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to attain a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
In an embodiment of the present invention, the system ground plane 120 is disposed on the substrate 13, the metal ring 130 is connected to the first housing 11 and cooperatively construct as a portion of the exterior (appearance), and the metal ring 130 and the first housing 11 cooperatively form a space to accommodate the substrate 13, related electronic components (such as an electronic component 14 and an electronic component 15) and related electronic circuits. In this manner, the metal ring 130 acts as a segment of the bezel and/or an outer frame, and can also be regarded as a portion of the exterior (appearance). Moreover, the metal ring 130 can be electrically coupled to the system ground plane 120 via a ground end 131 and a ground end 132.
The resonant cavity 140 is formed between the system ground plane 120 and the metal ring 130 to construct a slot antenna with the metal ring 130 and generate a first resonant mode (or a first high-frequency mode), for example, an operating frequency band(s) of DCS-1800 and/or PCS-1900.
In this embodiment, a transverse dimension L of the metal ring 130, a longitudinal dimension W of the metal ring 130 and a first gap width G1 of the resonant cavity 140 are used to control at least one of a resonant frequency of the first resonant mode, a bandwidth of the first resonant mode and a return loss of the first resonant mode. In practice, the transverse dimension L of the metal ring 130 can be 65 mm, the longitudinal dimension W of the metal ring 130 can be 16 mm and the first gap width G1 of the resonant cavity 140 can be 6 mm, in order to precisely control the resonant frequency (also known as the central operating frequency) of the first resonant mode within the operating frequency bands of DCS-1800 and PCS-1900, namely, between 1710 MHz and 1990 MHz.
In an embodiment of present invention, the multi-band antenna 100 further includes a first metal element 171. The first metal element 171 is disposed inside the resonant cavity 140, and may be electrically coupled to the system ground plane 120 via the metal ring 130. The electrical length of the first metal element 171 is used to adjust a length of a current path for controlling the resonant frequency of the first resonant mode. For example, when the electrical length of the first metal element 171 is increased, the current path is lengthened, and accordingly the central operating frequency of the first resonant mode is decreased.
The first radiating portion 161 can be disposed on the second housing 12. When the first housing 11 and the second housing 12 are connected to each other, the first radiating portion 161 can be electrically coupled to the feeding portion 110 for generating a second resonant mode. Similarly, the second radiating portion 162 can be disposed on the second housing 12. When the first housing 11 and the second housing 12 are connected to each other, the second radiating portion 162 can be electrically coupled to the feeding portion 110, for generating a third resonant mode.
In an embodiment of present invention, the multi-band antenna 100 further includes a first conductive portion 151 and a second conductive portion 152. The first conductive portion 151 can be disposed on the second housing 12. The first radiating portion 161 is electrically coupled to one side of the first conductive portion 151, and the second radiating portion 162 is electrically coupled to another side of the first conductive portion 151. When the first housing 11 and the second housing 12 are connected to each other, the first conductive portion 151 can be electrically coupled to the feeding portion 110. The second conductive portion 152 can be disposed on the second housing 12 and electrically coupled to the first conductive portion 151. When the first housing 11 and the second housing 12 are connected to each other, the second conductive portion 152 can be electrically coupled to the metal ring 130.
In this embodiment, when the first housing 11 and the second housing 12 are connected to each other, a projection of the first conductive portion 151 with respect to the normalized view of the substrate 13 at least partially overlaps the resonant cavity 140. In practice, the first conductive portion 151 and the resonant cavity 140 would not directly be connected with each other. It is partially with projection overlap from the view of the normalized plane.
In an embodiment of the presented invention, when the electrical length (or resonant path) of the second radiating portion 162 is longer than the electrical length of the first radiating portion 161, the resonant frequency (also known as the central operating frequency) of the third resonant mode (or the first low frequency mode, e.g., GSM-900) is smaller than the resonant frequency of the second resonant mode (or the second high frequency mode, e.g., UMTS-2100). On the other hand, when the electrical length of the second radiating portion 162 is shorter than the electrical length of the first radiating portion 161, the resonant frequency of the third resonant mode is larger than the resonant frequency of the second resonant mode.
In an embodiment of the present invention, the multi-band antenna 100 further includes a second metal element 172 and a third metal element 173. Both of the metal elements 172, 173 are disposed on the second housing 12 and electrically coupled to the first conductive portion 151, in which the electrical length of the second metal element 172 is used to adjust an impedance matching of the first radiating portion 161, and the electrical length of the third metal element 173 is used to adjust an impedance matching of the second radiating portion 162. Therefore, by adjusting the electrical length of the second metal element 172, at least one of the resonant frequency, the bandwidth and return loss of the second resonant mode can be controlled. Similarly, by adjusting the electrical length of the third metal element 173, at least one of the resonant frequency, the bandwidth and return loss of the third resonant mode can be controlled. It is noted that the second metal element 172 and the third metal element 173 are not the essential elements of this embodiment, and a person skilled in the art can dispose related matching circuits on the substrate 13 to realize impedance matching, and this embodiment is not intended to limit the present invention.
In an embodiment of the present invention, the feeding portion 110 can be disposed on the substrate 13 and have a metal spring (or a pogo pin) 111. When the first housing 11 and the second housing 12 are connected to each other, the metal spring 111 can be electrically coupled to the first conductive portion 151 for feeding an interior radio frequency (RF) signal, processed from an RF circuit (not shown) on the substrate 13, to the feeding portion 110, and then transmitting the signal to (a) the first radiating portion 161 and/or the second radiation portion 162, and (b) the first conductive portion 151, the second conductive portion 152 and the metal ring 130. Similarly, an external RF signal can also be fed to the RF circuit and related electrical components on the substrate 13 via the same path, and an explanation of the operation in this regard will not be repeated herein.
In an embodiment of the present invention, the first conductive portion 151, the second conductive portion 152, the first radiation portion 161 and the second radiation portion 162 are disposed on a first surface S1 of the second housing 12. In addition, the multi-band antenna further includes a third conductive portion 153 disposed on the second housing 12. The third conductive portion 153 is electrically coupled to the first conductive portion 151 and penetrates through the first surface S1 and a second surface S2 of the second housing 12. When the first housing 11 and the second housing 12 are connected to each other, the feeding portion 110 is electrically coupled to the first conductive portion 151 via the third conductive portion 153.
In an embodiment of the present invention, the metal ring 130 is a continuous metal structure. The structure of the bezel and/or outer frame of the portable communication device 10 is complete when the metal ring 130 is connected with the first housing 11, so that the performance of the multi-band antenna is minimally interfered with by external objects. In addition, the first housing 11 can be constructed using metal or non-metal. In this embodiment, the electronic element 14 (e.g., a vibrator) and the electronic element 15 (e.g., a microphone) and related electronic circuits can be disposed on the substrate 13 without arranging slot(s), to utilize the space of the portable communication device 10 efficiently.
It is noted that when the first housing 11 and the second housing 12 are connected to each other, the feeding portion 110, the first conductive portion 151, the second conductive portion 152, the third conductive portion 153, the first radiating portion 161, the second radiating portion 162, the second metal element 172 and the third metal element 173 can form an overall structure of a PIFA. The PIFA can connect to the ground end 131 and the ground end 132 via the second conductive portion 152, in which both the ground ends 131, 132 are disposed on the metal ring 130. All the parts of the PIFA can be formed using typical iron elements, copper foil, laser direct structuring (LDS) or by coating conducting liquid and/or paint, and perforation techniques may additionally be used. Furthermore, there is a second gap width G2 between the first radiating portion 161 and an edge of the second housing 12, and the second gap width G2 can be adjusted to control at least one of the resonant frequency of the second resonant mode, the bandwidth of the second resonant mode and the return loss of the second resonant.
For example, within the frequency band of the first resonant mode DCS-1800/PCS-1900 and the second resonant mode UMTS-2100, namely 1710 MHz˜2170 MHz, the radiation efficiency of the first multi-band antenna 100 is larger than 44%. On the other hand, within the frequency band of the third resonant mode GSM-900, namely 880 MHz˜960 MHz, the radiation efficiency of the first multi-band antenna 100 is larger than 36%.
In an embodiment of the present invention, the first conductive portion 251, the second conductive portion 252, the first radiating portion 261 and the second radiating portion 262 are disposed on the second surface S2 of the second housing 22. Therefore, when the first housing 21 and the second housing 22 are connected to each other, the feeding portion 210 can be directly electrically coupled to the first conductive portion 251 for feeding RF signals, without having to go through the third conductive portion 153 as shown in
In summary, through implementing the features of the subject application, a multi-band antenna with slot antenna(s) and PIFA(s) can be constructed and the space inside the portable communication device can be increased. Moreover, the interference caused by external objects can be reduced by deploying a continuous metal ring. Therefore, the bandwidth, the antenna gain, and the antenna radiation efficiency of the portable communication device can be improved, and the communication quality of the portable communication device is ensured.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.
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| Number | Date | Country |
|---|---|---|
| 101682119 | Nov 1995 | CN |
| Entry |
|---|
| SeongTae Jeong et al.: “Design and analysis of Multi-band antenna for mobile handset applications”, Antennas and Propagation Society International Symposium, 2009. APSURSI' 09. IEEE, IEEE, Piscataway, NJ, USA, Jun. 1, 2009, pp. 1-4. |
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| Number | Date | Country | |
|---|---|---|---|
| 20130135156 A1 | May 2013 | US |
