Patent Publication Number: US-9419338-B2

Title: Antenna apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an antenna apparatus, and particularly relates to an antenna apparatus for improving a radiation pattern. 
     2. Description of Related Art 
     With the development of communication technology, the application of wireless communication technology in electronic products increases day by day, which results in the diversification of communication products. For example, cell phones, personal digital assistants (PDAs) with wireless network capability, and the global positioning system (GPS) are all related to wireless communication. In recent years, since consumers have more demands regarding the functions of communication products, communication products with various functions and designs have been developed, and computer network products with wireless communication capability have become more popular recently. 
     As for wireless communication products, the most crucial point is the design of an antenna, because the design quality of the antenna tends to influence the quality of communication. Generally, antennas include internal antennas and external antennas. External antennas include monopole antennas, dipole antennas and helix antennas. Internal antennas include planar inverted F antennas (PIFA) and microstrip antennas. The planar inverted F antennas are widely used in communication products. 
     The conventional wireless communication techniques mainly use patch antennas to generate a broadside radiation patterns. However, due to the space required by a patch antenna, patch antennas may not be applicable in miniatured communication products. As a result, the conventional way of handling this issue is to use the planar inverted F antennas to reduce the space taken by the antenna. However, the radiation patterns of the planar inverted F antennas are prone to be influenced by the components disposed around, so the distribution of the radiation patterns of the planar inverted F antennas is limited. 
     SUMMARY OF THE INVENTION 
     The invention provides an antenna apparatus capable of improving a radiation pattern of an antenna. 
     An antenna apparatus of the invention includes a radiating plate, a ground layer, a dielectric layer, and a parasitic antenna. The radiating plate is configured to receive or emit a radio frequency signal. The ground layer is configured for grounding. The dielectric layer is disposed between the radiating plate and the ground layer, and the radiating plate and the ground layer are parallel with each other. The parasitic antenna is connected with the ground layer, and an extending direction of the parasitic antenna is parallel to a normal direction of the ground layer. 
     In an embodiment of the invention, the radiating plate includes a feed-in part and a short circuit part. The feed-in part has a feed-in point. The radiating plate is electrically connected with a feed-in line through the feed-in part. The short circuit part is electrically connected with the ground layer. 
     In an embodiment of the invention, the radiating plate has an open slot, such that the radiating plate forms a C-shaped pattern, and an opening of the C-shaped pattern is adjacent to the feed-in part and the short circuit part. 
     In an embodiment of the invention, the parasitic antenna is disposed beside the opening of the C-shaped pattern. 
     In an embodiment of the invention, the C-shaped pattern has a long axis and a short axis, the opening of the C-shaped pattern is at a position close to the short axis and close to a side where the feed-in part and the short circuit part are disposed. 
     In an embodiment of the invention, a length of the C-shaped pattern is a multiple of a quarter of a wavelength of a frequency transmitted or received by the antenna apparatus. 
     In an embodiment of the invention, the antenna apparatus is a planar inverted F antenna. 
     In an embodiment of the invention, the radiating plate has a feed-in point. 
     In an embodiment of the invention, a geometric shape of the radiating plate includes rectangle, triangle, circle, and ellipse. 
     In an embodiment of the invention, the parasitic antenna is disposed external to an area of the radiating plate projected onto the ground layer. 
     In an embodiment of the invention, the antenna apparatus is a patch antenna. 
     In an embodiment of the invention, a length of the parasitic antenna is a multiple of a quarter of a wavelength of a frequency transmitted or received by the antenna apparatus. 
     In an embodiment of the invention, the ground layer is located on a printed circuit board. 
     Based on the above, the parasitic antenna that extends in the direction parallel to the normal direction of the ground layer is disposed on the ground layer in the invention to improve the radiation pattern of the antenna, thereby facilitating the communication quality of the electronic product using the antenna apparatus. 
     To make the above features and advantages of the invention more comprehensible, embodiments accompanied with drawings are described in detail as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side view illustrating an antenna apparatus according to an embodiment of the invention. 
         FIG. 2A  is a schematic side view illustrating an antenna apparatus according to another embodiment of the invention. 
         FIG. 2B  is a schematic oblique view illustrating the antenna apparatus in the embodiment shown in  FIG. 2A . 
         FIGS. 2C and 2D  are schematic views illustrating a laptop computer disposed with an antenna apparatus according to an embodiment of the invention. 
         FIG. 3  is a schematic oblique view illustrating an antenna apparatus according to another embodiment of the invention. 
         FIG. 4  is a schematic oblique view illustrating an antenna apparatus according to another embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     It is to be understood that both the foregoing and other detailed descriptions, features and advantages are intended to be described more comprehensively by providing an embodiment accompanied with figures hereinafter. The language used to describe the directions such as up, down, left, right, front, back or the like in the reference drawings is regarded in an illustrative rather than in a restrictive sense. Thus, the language used to describe the directions is not intended to limit the scope of the invention. 
       FIG. 1  is a schematic side view illustrating an antenna apparatus according to an embodiment of the invention. Referring to  FIG. 1 , an antenna apparatus  100  includes a radiating plate  102 , a ground layer  104 , a dielectric layer  106 , and a parasitic antenna  108 . The dielectric layer  106  is disposed between the radiating plate  102  and the ground layer  104 , and the radiating plate  102  and the ground layer  104  are parallel to each other. The radiating plate  102  may be a metal plate or a plate-like component with metal coated on its surface, and the radiating plate  102  is configured to receive or emit a radio frequency signal. The ground layer  104  may be a ground metal plate or a ground plane on a printed circuit board (PCB) for grounding. 
     In addition, the parasitic antenna  108  is connected with the ground layer  104 . The parasitic antenna  108  is disposed external to an area of the radiating plate  102  projected onto the ground layer  104 , and an extending direction of the parasitic antenna  108  is parallel to a normal direction of the ground layer  104 . In addition, a length of the parasitic antenna  108  is a multiple of a quarter of a wavelength of a frequency transmitted or received by the antenna apparatus  100 . By disposing the parasitic antenna  108  perpendicular to the ground layer  104  on the ground layer  104 , a radiation pattern generated by the antenna apparatus  100  is allowed to be more condensed upwardly. Namely, signals radiated by the antenna apparatus  100  may be directed more consistently to the extending direction of the parasitic antenna  108 , thereby facilitating a communication quality of an electronic product using the antenna apparatus  100 . 
       FIG. 2A  is a schematic side view illustrating an antenna apparatus according to another embodiment of the invention.  FIG. 2B  is a schematic oblique view illustrating the antenna apparatus in the embodiment shown in  FIG. 2A . As shown in  FIGS. 2A and 2B , in this embodiment, an antenna apparatus  200  is a patch antenna, a radiating plate  202  is a rectangular metal plate or a plate-like component with metal coated on its surface, and there is a feed-in point FI on the radiating plate  202 . The feed-in point FI may be connected with one end of a feed-in line (now shown), whereas another end of the feed-in line may be connected with a signal source (not shown), such that the signal source may feed signals to the feed-in point FI through the feed-in line, thereby sending the signals in a form of electromagnetic waves through the radiating plate  202 . When a coaxial cable serves as the feed-in line, one end of a core conductor for signal transmission may be connected to the feed-in point FI, and another end that serves as an outer conductor for signal shielding is connected with the ground layer  104 . 
     It should be noted that although the embodiment is described with the radiating plate  202  in a rectangular shape as an example, the shape of the radiating plate  202  is not limited thereto. In some embodiments, the radiating plate  202  may be shaped in other geometric forms, such as rectangle, triangle, circle, and ellipse, etc. In addition, a position of the feed-in point FI is not limited to the position shown in  FIG. 2A , either. The designer may modify the position of the feed-in point FI according to the requirements in practical use. 
     Furthermore, the parasitic antenna  108  is not limited to be perpendicular to the ground layer  104 . The parasitic antenna  108  may be disposed as an adjustable antenna as well.  FIGS. 2C and 2D  are schematic views illustrating a laptop computer disposed with an antenna apparatus according to an embodiment of the invention. A laptop computer  250  shown in  FIG. 2C  includes a top cover  251  and a bottom cover  252 . The top cover  251  further includes a display surface  251 A. In this embodiment, the antenna apparatus  200  is disposed in the top cover  251 , and an angle of the parasitic antenna  108  may be adjusted toward the Z-axis direction, i.e. parallel to an extending direction of a plane of the top cover  251 , to obtain preferable signal transmission. It should be noted that the angle of the parasitic antenna  108  is not limited thereto. The angle of the parasitic antenna  108  may range within an included angle of the normal direction of the top cover  251  and the plane thereof. Referring to  FIG. 2D , when the top cover is folded to the bottom cover  252  and the display surface  251 A faces outside, the parasitic antenna  108  may stop functioning as being shielded by other components disposed in the bottom cover  252  of the laptop computer  250 . And a signal-receiving signal direction then is a direction that the radiating plate  202  faces, i.e. the signal-receiving direction is still the z-axis direction. 
       FIG. 3  is a schematic oblique view illustrating an antenna apparatus according to another embodiment of the invention. The antenna apparatus  300  shown in  FIG. 3  is a planar inverted F antenna. A radiating plate  302  further includes a feed-in part  302 A and a short circuit part  302 B extending toward a direction of the ground layer  104  in addition to a part parallel with the ground layer  104 . The short circuit part  302 B is electrically connected with the ground layer  104 , and the feed-in part  302 A has the feed-in point FI to be connected with the feed-in line (not shown) for receiving the signals from the signal source (not shown) and transmitting the signals to the radiating plate  302  parallel with the ground layer  104 , thereby transmitting the signals in the form of electromagnetic waves. In addition, the radiating plate  302  parallel with the ground layer  104  includes an open slot OP, such that the radiating plate  302  parallel with the ground layer  104  is presented in a C-shaped pattern, and an opening of the C-shaped pattern is adjacent to the feed-in part  302 A and the short circuit part  302 B. 
     As shown in  FIG. 3 , the C-shaped pattern of the radiating plate  302  has a long axis X and a short axis Y, and the opening of the C-shaped pattern is close to the short axis Y and close to a side at which the feed-in part  302 A and the short circuit part  302 B are disposed. In addition, the parasitic antenna  108  is disposed beside the opening of the C-shaped pattern, so as to make a radiation pattern generated by the antenna apparatus  300  more condensed upwardly, thereby improving a communication quality of an electronic product using the antenna apparatus  300 . The length of the parasitic antenna  108  is a multiple of a quarter of a wavelength of a frequency transmitted or received by the antenna apparatus  300 , and a length of the C-shaped pattern (indicated by a length of a dotted line shown in  FIG. 3 ) is also a multiple of a quarter of the wavelength of the frequency transmitted or received by the antenna apparatus  300 . 
     It should be noted that the opening of the C-shaped pattern described above is not limited to a position shown in the embodiment of  FIG. 3 . The designer may dispose the opening of the C-shaped pattern to a different position according to practical use. The antenna  108  is then disposed in a different position as the position of the opening of the C-shaped pattern differs. In addition, the C-shaped pattern is not limited to necessarily have the long and short axes. For example, the C-shaped pattern may substantially be a circular pattern having an opening. 
     In some embodiments, the pattern of the radiating plate  302  parallel to the ground layer  104  may not be limited to the C-shaped pattern. The designer may design an antenna pattern for the radiating plate  302  as required according to practical use. By disposing the parasitic antenna  108  perpendicular to the ground layer  104  on the ground layer  104 , the radiation pattern of the antenna apparatus becomes condensed upwardly, thereby facilitating the communication quality of the electronic product using the antenna apparatus. 
     It should be noted that the embodiment regarding the parasitic antenna  108  of the antenna apparatus is only an exemplary embodiment. The parasitic antenna  108  is not required to be strictly perpendicular to the ground layer  104  in practical use. For example,  FIG. 4  is a schematic oblique view illustrating an antenna apparatus according to another embodiment of the invention. Referring to  FIG. 4 , an antenna apparatus  400  of this embodiment differs from the antenna apparatus  200  in that the parasitic antenna  108  includes a vertical part  108 A, a first extension part  108 B, and a second extension part  108 C, while the length of the parasitic antenna  108  in total is still a multiple of a quarter of a wavelength of a frequency transmitted or received by the antenna apparatus  400 . The vertical part  108 A and the first extension part  108 B are located at a first side S 1  of the radiating plate  202 . One end of the vertical part  108 A is connected with the ground layer  104 , and an extending direction of the vertical part  108 A is parallel to the normal direction of the ground layer  104 . One end of the first extension part  108 B is connected with another end of the vertical part  108 A, and an extending direction of the first extension part  108 B is parallel to the first side S 1  of the radiating plate  202  and the ground layer  104 . In addition, an included angle of a plane formed by the first extension part  108 B and the first side S 1  and a plane of the radiating plate  202  ranges between 15° and 80°, a horizontal distance between the first extension part  108 B and the first side S 1  of the radiating plate  202  is a first length t 1 , and the first length t 1  substantially ranges between 1 to 3 mm. Moreover, the second extension part  108 C is connected with another end of the first extension part  108 B, an extending direction of the second extension part  108 C is parallel to a second side S 2  of the radiating plate  202 , and a horizontal distance between the second extension part  108 C and the second side S 2  of the radiating plate  202  is a second length t 2 , and the second length t 2  substantially ranges between 1 to 3 mm. A total length of the vertical part  108 A, the first extension part  108 B, and the second extension part  108 C is greater than or equal to one-eighth of the wavelength of the frequency transmitted or received by the antenna apparatus  300  Besides, in some embodiments, shapes of the first extension part  108 B and the second extension part  108 C are not limited to the shapes of the first extension part  108 B and the second extension part  108 C shown in this embodiment. In some embodiments, the first extension part  108 B and the second extension part  108 C may be in different shapes to extend to the above of the radiating plate  202 , so as to adjust a radiation pattern of the antenna apparatus  400 . 
     In view of the above, the parasitic antenna that extends in the direction parallel to the normal direction of the ground layer is disposed on the ground layer in the invention to improve the radiation pattern of the antenna, thereby facilitating the communication quality of the electronic product using the antenna apparatus. 
     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 and their equivalents.