Patent Application
20140118207
1. Technical Field
The disclosure generally relates to antennas, and particularly to a wideband antenna assembly having a reduced size.
2. Description of Related Art
In wireless communication devices such as mobile phones and personal digital assistants, antenna devices to transmit and exchange radio data by transmitting and receiving electromagnetic waves are an essential element.
To realize a suitability of wireless communication devices for different communication systems, wideband antenna are used to allow transmission and receiving of multiple frequency bands for different communication systems. However, many wideband antennas have complicated structures and large sizes, making it difficult to miniaturize portable electronic devices.
Therefore, there is room for improvement within the art.
Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure.
The base board 10 is made of dielectric material such as epoxy resin glass fiber. In this embodiment, the dielectric coefficient of the dielectric material is εr. The base board 10 is substantially a flat board including a first surface 101 and a second surface 102 parallel and opposite to the first surface 101.
The ground plane 20 is positioned on the first surface 101 and configured to provide ground for the antenna assembly 100. In this embodiment, the ground plane 20 is a layer of conductive foil, such as copper foil, plated on the first surface 101.
In this embodiment, the feed portion 30 is a microstrip line. A first end of the feed portion 30 is attached to the second surface 102 and extends to the first surface 101 with a second end of the feed portion 30 attached to the first surface 101. The first end of the feed portion 30 is electrically connected to a radio frequency (RF) circuit positioned inside the wireless communication device and configured to obtain current from the RF circuit to transmit radio signals. The second end of the feed portion 30 partially overlaps the ground plate 20. In this embodiment, the feed portion 30 is a strip-shaped body of even width. In addition, the width, length, and the shape can be adjusted to make the antenna assembly 100 have a maximal bandwidth.
The radiating portion 50 is formed on the ground plane 20 by removing a portion of the ground plane 20 (i.e. the layer of the conductive foil on the base board 10 to expose the dielectric material of the base board 10) and forming a slot antenna. The radiating portion 50 includes a first exposed dielectric portion 51, a second exposed dielectric portion 53, and a third exposed dielectric portion 55. In this embodiment, the first exposed dielectric portion 51 and the second exposed dielectric portion 53 are parallel and oppositely positioned strips. The third exposed dielectric portion 55 is also a strip and positioned between the first exposed dielectric portion 51 and the second exposed dielectric portion 55 with two ends of the third exposed dielectric portion 55 perpendicularly connected to the first exposed dielectric portion 51 and the second exposed dielectric portion 53. The first exposed dielectric portion 51, the second exposed dielectric portion 53, and the third exposed dielectric portion 53 form a substantially H-shaped closed structure.
Referring to
Referring to
Referring to
In addition, a distance between the third exposed dielectric portion 55 and one end of the first exposed dielectric portion 51 is defined as L1. A distance between the third exposed dielectric portion 55 and one end of the second exposed dielectric portion 53 is defined as L3. A distance between third exposed dielectric portion 55 and another end of the second exposed dielectric portion 53 is defined as L4. Bandwidths of the first frequency band, the second frequency band, and the third frequency band of the antenna assembly 100 can be adjusted by changing a second group of parameters which comprise Ws, Ls, f, b, and w. Specifically, a first central frequency fr1, a second central frequency fr2, and a third central frequency fr3 corresponding to the first frequency band, the second frequency band, and the third frequency band satisfy formulas (1)-(3):
Wherein, c and εeff represent speed of light and dielectric coefficient, and satisfy formula (4):
In use, the signals are fed into the feed portion 30 and obtain different paths for the flow of current by the feed portion 30 and the radiating portion 50, to generate different signals so that the antenna assembly 100 can enter a resonance mode at the first central frequency about 1.575 GHz, at the second central frequency about 2.4 GHz, and at the third central frequency about 5.2 GHz, and work effectively in the first frequency band, the second frequency band about 2.38 GHz-2.834 GHz, and the third frequency band about 4.66 GHz-6.3 GHz.
Referring to
The antenna assembly 100 forms the radiating portion 50 by exposing portions of the ground plane 20 and coupling the radiating portion 50 with the feed portion 30. Because of the exposed radiating portion 50, a size of the antenna assembly 100 is small and is advantageous in the miniaturization of the wireless communication device.
It is believed that the exemplary embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 101140224 | Oct 2012 | TW | national |
