This Application claims priority of Taiwan Patent Application No. 100140659, filed on Nov. 8, 2011, the entirety of which is incorporated by reference herein.
1. Field of the Invention
The present invention relates to a wireless signal transmission device, and in particular relates to a wireless signal transmission device transmitting circular polarized signals.
2. Description of the Related Art
Conventional circular polarized satellite signal receivers are made by inserting a medium sheet into a linear polarized signal receiver to transform the linear polarized signal receiver into a circular polarized signal receiver. However, the medium sheet inserted in the polarized signal receiver reduces signal isolation (Cx-pol, which is defined by a ratio of Co-polarization to Cross-polarization) thereof, and the signal transmission efficiency of the conventional circular polarized satellite signal receiver is therefore poor.
A wireless signal transmission device is provided. The wireless signal transmission device includes a reflective surface and a receiver. The reflective surface reflects a wireless signal. The receiver receives the wireless signal reflected from the reflective surface. The receiver includes a receiver body, a wave guide, a transmission unit and a medium sheet. The wave guide includes an opening end and a connection end, wherein the connection end is connected to the receiver body. The transmission unit is disposed in the wave guide adjacent to the connection end, wherein the transmission unit receives the wireless signal. The medium sheet is disposed in the wave guide, wherein the medium sheet comprises a first section and a second section, the first section is adjacent to the transmission unit, the second section is adjacent to the opening end, the first section has a first dielectric constant, the second section has a second dielectric constant, and the first dielectric constant is smaller than the second dielectric constant.
In the wireless signal transmission device of the embodiment of the invention, the first section adjacent to the transmission unit is made of PP, which has a lower dielectric constant. The Noise Factor of the wireless signal transmission device is therefore improved. The second section adjacent to the opening end is made of ABS, which has a higher dielectric constant. The signal isolation (Cx-pol) and signal transmission efficiency of the wireless signal transmission device is therefore improved. In one embodiment, the wireless signal transmission device improves high band (11.7 GHz˜12.2 GHz) circular polarized signal transmission efficiency.
The Applicant discovered that by utilizing the PP made first section with a lower dielectric constant adjacent to the transmission unit and by utilizing the ABS made second section with higher dielectric constant adjacent to the opening end, the Noise Factor and the signal isolation (Cx-pol) of the wireless signal transmission device can be improved simultaneously.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
With reference to
In the wireless signal transmission device of the embodiment of the invention, the first section 241 adjacent to the transmission unit 23 is made of PP, which has a lower dielectric constant. The Noise Factor of the wireless signal transmission device is therefore improved. The second section 242 adjacent to the opening end 221 is made of ABS, which has a higher dielectric constant. The signal isolation (Cx-pol) and signal transmission efficiency of the wireless signal transmission device is therefore improved. In one embodiment, the wireless signal transmission device improves high band (11.7 GHz ˜12.2 GHz) circular polarized signal transmission efficiency.
The Applicant discovered that by utilizing the PP made first section 241 with lower dielectric constant adjacent to the transmission unit 23 and by utilizing the ABS made second section 242 with higher dielectric constant adjacent to the opening end 221, the Noise Factor and the signal isolation (Cx-pol) of the wireless signal transmission device can be improved simultaneously. In one embodiment, when the difference between the first dielectric constant of the first section and the second dielectric constant of the second section is within the range of 0.5˜1, transmission improvement is significant. In another embodiment, the difference between the first dielectric constant of the first section and the second dielectric constant of the second section can be 0.5, 0.8 or 1. After experimentation, when the difference between the first dielectric constant of the first section and the second dielectric constant of the second section is 1, an improved Xpol performance of the wireless signal transmission device can be achieved, for example, the first dielectric constant can be 2.3 and the second dielectric constant can be 3.3.
In the embodiment above, PP and ABS are utilized in the medium sheet. However, the invention is not limited thereby. The material of the medium sheet can be changed for different transmission requirements. In a modified example, as shown in
With reference to
The medium sheet 24 comprises a first end 243 and a second end 244, the first end 243 is toward the transmission unit 23, the second end 244 is toward the opening end 221 of the wave guide 22, a first distance d1 is formed between the first end 243 and the transmission unit 23, and a second distance d2 is formed between the second end 244 and the opening end 221 of the wave guide 22. In this embodiment, the first distance dl is about 6.5 mm˜6.9 mm, and the second distance d2 about 9.5 mm˜9.8 mm.
With reference to
With reference to
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 a 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 is to be understood that the invention is not limited to the disclosed embodiments. To 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 |
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100140659 A | Nov 2011 | TW | national |
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Number | Date | Country | |
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20130115873 A1 | May 2013 | US |