1. Field of the Invention
The present invention relates to an antenna module for reducing frequency shift and a portable electronic device employing the same.
2. Discussion of the Related Art
As the demand for thin and light cellular phones grows, the design of hidden antennas has become increasingly popular. To minimize the volume of cellular phones, the traces of antennas have to be adequately designed to keep the volume of cellular phones down yet simultaneously achieve stable signal strengths.
Nowadays, high frequency antennas and low frequency antennas are often used together in cellular phones. The antennas are susceptible to interference from electromagnetic waves. As a consequence, to prevent the antennas from electromagnetic interference, the antennas are oriented away from circuit boards of the cellular phones. Additionally, the high frequency antenna and low frequency antenna need to be spaced from each other to avoid a coupling effect, which deteriorates the radiation efficiency. However, for clamshell/flip phones, such a design is only beneficial when the clamshell/flip phone is in an opened state. When the clamshell/flip phone is closed, the radiation efficiency may be deteriorated by frequency shift resulting from the antennas being too close to the cover of the clamshell/flip phones and the variation of the ground area. That is to say, the radiation efficiency of the clamshell/flip phones with such design is ineffective when the clamshell/flip phone is in a closed state.
Therefore, what is needed is an antenna module for reducing frequency shift and a portable electronic device employing the antenna.
Many aspects of the antenna module can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon clearly illustrating the principles of the present antenna module. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
The antenna set 40 includes a first antenna 42, a second antenna 44, a feed point 46 and a ground 48. The first antenna 42 and the second antenna 44 are mainly mounted on the external end surface 22 of the antenna holder 21, and the feed point 46 and the ground 48 are arranged on the top surface 24 of the antenna holder 21. In the exemplary embodiment, the first antenna 42 is a high frequency antenna and the second antenna 44 is a low frequency antenna. Thus, the first antenna 42 is shorter than the second antenna 44. As shown in
The first antenna 42 includes a main portion 422, a first connecting portion 424 and a second connecting portion 426. The main portion 422 is mainly mounted on the upper edge 22a of the middle portion 222. The first connecting portion 424 extends from the main portion 422 and is mounted on the top surface 24 so that the first connecting portion 424 connects to the feed point 46. The second connecting portion 426 extends from the first connecting portion 424 and is mounted on the top surface 24 as a meandering-line structure. In addition, the second connecting portion 426 electrically connects to the ground 48 arranged on the top surface 24.
The second antenna 44 includes a front section 442, a main section 444, a bent section 446 and an end section 448. For clearness, dotted lines are shown in
The bent section 446 further includes a first bent portion 4461 and a second bent portion 4462. The first bent portion 4461 extends from the main section 444 and is upwardly bent. The second bent portion 4462 extends from the first bent portion 4461 and is bent in a further direction of the first antenna 42 so that it is mounted on the upper edge 22a of the external end surface 22 and does not overlap the first antenna 42. In this way, the first bent portion 4461 and the second bent portion 4462 can prevent the second antenna 44 from being affected by the circuit board within the flip cover 102 as the portable electronic device is in a closed state thereby improving the radiation efficiency of the antenna module 20.
Referring to
As described above, the antenna module 20 may be used by various cellular phones, beyond the cellular phone illustrated, and/or with other devices needing an antenna module that facilitates the achievement of fully open and fully closed positions.
It is believed that the present 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 invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.
Number | Date | Country | Kind |
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200810301375.6 | Apr 2008 | CN | national |