The present invention relates a negative refractivity medium, and more particularly to a dielectric resonator for a negative refractivity medium.
With the advance of science and technology, the wireless communication products used in various fields, including industry, science and medicine, are gradually diversified. Among them, in-vehicle phones and mobile phones grow especially fast. The state-of-the-art communication devices feature portability and low power consumption. The high frequency and middle high-frequency performance of the resonators, filters, capacitors, etc. used in the mobile communication devices are considered to be very important. Further, how to reduce the size and power consumption of devices is also an important topic in designing products.
When used in a WLAN (Wireless Local Area Network) system operating at a frequency band of 5.25 GHz, the conventional microstrip antenna has too high a conductor ohmic loss because of the high operation frequency. In the same case, the conventional dielectric resonator antenna does not have any conductor ohmic loss but has high radiation efficiency, low consumption and a high gain. Therefore, the dielectric resonator antenna is very suitable to be used in such a high frequency band. The conventional dielectric resonator antenna usually uses a material having a permittivity of 20-30 and has a height higher than the microstrip antenna. Sometimes, a dielectric resonator antenna adopts a material having a high permittivity (normally higher than 70) to reduce the size thereof, and more particularly to reduce the height thereof. However, a high permittivity causes a decreased operation bandwidth, which usually cannot meet the requirement of the bandwidth.
The BaO-rare earth oxide-TiO2 system ceramic is one of the materials able to satisfy the abovementioned requirement. The BaO-rare earth oxide-TiO2 system ceramic not only is likely to realize the miniaturization of the antenna but also is likely to achieve a high permittivity and a low dielectric loss. However, the BaO-rare earth oxide-TiO2 system ceramic suitable for smaller high frequency devices has a very high permittivity. It is difficult and expensive to obtain a lower-permittivity BaO-rare earth oxide-TiO2 system ceramic via introducing other additional components.
Accordingly, the present invention proposes a novel and advanced dielectric resonator technology to overcome the abovementioned problems.
The primary objective of the present invention is to provide a dielectric resonator for a negative refractivity medium, which features lower dielectric loss and isotropy.
To achieve the abovementioned objective, the present invention proposes a dielectric resonator for a negative refractivity medium, which is coupled to a plurality of substrates and comprises at least one crystal unit, at least one first crystal cube and at least one second crystal cube, wherein the crystal units are arrayed on the substrate, and wherein on an identical substrate, each crystal unit has a first spacing with respect to one adjacent crystal unit and a second spacing with respect to another adjacent crystal unit, and the first spacing is vertical to the second spacing, and wherein each crystal unit has one first crystal cube and one second crystal cube, and wherein a third spacing exists between the first and second crystal cubes, and wherein the first and second crystal cubes have a permittivity greater than 20.
The dielectric resonator for a negative refractivity medium of the present invention has the following advantages:
1. The present invention adopts a material have a permittivity greater than 20 to overcome the conventional problem of high dielectric loss. Thus, the present invention has a lower dielectric loss. Further, the present invention also features isotropy. Therefore, the present invention has significant industrial utility.
2. The present invention can easily overcome the conventional problem that the small-volume and low-permittivity elements are hard to assemble, via arranging many sets of two crystal cubes made of an identical material into an array. Therefore, the present invention can effectively reduce the fabrication cost and has high industrial utility.
Below, the embodiments are described in detail to demonstrate the technical contents of the present invention. However, the embodiments are only to exemplify the present invention but not to limit the scope of the present invention.
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The substrate 10 is made of polystyrene. Polystyrene has a permittivity near the permittivity of air. The crystal unit 20 thus has a fourth spacing 220 vertical to the substrates 10 and separating the substrates 10. In this embodiment, the first spacing 201 is defined to be the X axis, the second spacing 202 is defined to be the Y axis, and the fourth spacing 220 is defined to be the Z axis.
The first spacing 201 ranges from 40 to 50 mm with 47.549 mm preferred. The second spacing 202 ranges from 20 to 30 mm with 22.149 mm preferred. The third spacing 203 ranges from 7 to 8 mm with 7.5 mm preferred. The fourth spacing 220 ranges from 20 to 30 mm with 22 mm preferred.
The volume of the first crystal cube 21 ranges from 7×7×10 to 10×10×10 mm3 with 10×10×10 mm3 preferred. The volume of the second crystal cube 22 ranges from 2×2×10 to 7×7×10 mm3 with 6.5×6.5×10 mm3 preferred. The material of the first and second crystal cubes 21 and 22 is selected from the group consisting of zirconium dioxide (ZrO2), barium strontium titanate ((Ba,Sr)TiO3), titanium dioxide (TiO2), and lanthanum titanate (LaTiO3).
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In conclusion, the present invention adopts the crystal unit 20 containing the first crystal cube 21 and the second crystal cube 22 both having a permittivity greater than 20 to overcome the conventional problem of high dielectric loss. Thus, the present invention has an advantage of lower dielectric loss. Further, the present invention also features isotropy. Therefore, the present invention has significant industrial utility.
The present invention can easily overcome the conventional problem that the small-volume and low-permittivity elements are hard to assemble, via arranging the first and second crystal cubes 21 and 22, which are made of an identical material, on the substrate 10. Therefore, the present invention can effectively reduce the fabrication cost and has high industrial utility.
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Number | Date | Country | |
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20110050367 A1 | Mar 2011 | US |