Patent Application
20110187621
The present invention relates to an antenna using a complex structure in which dielectric substances having a low dielectric constant and magnetic substances having a high magnetic permeability are arranged in periodic grating arrangement in order to improve the gain, efficiency, and bandwidth of the antenna while maintaining a small size which is an advantage of a conventional antenna using dielectric substances having a high dielectric constant.
Several digital multimedia broadcasting systems including terrestrial wave DMB has recently just started being served in earnest. In preparation for the service, the development of portable terminals capable of receiving Digital Multimedia Broadcasting (DMB), as well as the broadcasting systems, is being developed.
Furthermore, a complex type terminal capable of receiving two kinds of services through one portable terminal is actively being developed in conjunction with the existing mobile phone system.
However, the frequency bands used in the DMBs are 174 to 216 MHz which is chiefly a low frequency band, such as UHF or VHF. Accordingly, there are several restrictions to the development of portable terminals.
The most significant restriction is a problem relating to the size of an antenna basically used in the portable terminal.
In general, the size of the antenna is increased with a used frequency being lowered. In order to fabricate an antenna for a UHF or VHF band, a length of several tens of cm is required. However, the antenna is not suitable to be used in the portable terminal. Accordingly, active research is being done on a reduction in the size of an antenna for the portable terminal.
The existing whip antenna or helical antenna of a monopole type is configured to protrude externally from the portable terminal, and thus the use of the antenna of this type is decreased. There is a lot of interest in a built-in type antenna which is fully put in the portable terminal and not externally protruded, and various portable terminals using the built-in type antenna are emerging.
One of the built-in type antennas is a Printed Circuit Board Antenna (hereinafter referred to as a ‘PCB antenna’).
The PCB antenna is characterized in that the shape of the antenna is chiefly flat. The PCB antenna can be easily implemented with a low cost and can solve problems in the process, as compared with a coil type antenna.
Referring to
However, the PCB antenna (that is, the built-in type antenna) shown in
In particular, a portable terminal for DMB operates in a low frequency band of 174 to 216 MHz, such as UHF or VHF, and has lots of difficulties in using the existing PCB antenna, such as that shown in
In order to solve the problems, a technique for constructing a substrate using high dielectric substances and forming a radiation pattern on the substrate has been developed and used. However, in the case where an antenna is implemented using high dielectric substances, a reduction in the size of the antenna may be achieved, but a disadvantage in that the gain and bandwidth of the antenna are decreased is inevitable.
The antenna using high dielectric substances as described above is not suitable for several DMB systems, including terrestrial wave DMB, which require a wide bandwidth and a high gain. Accordingly, there is a need for the development of a method of reducing the size of an antenna and satisfying a wide bandwidth and a high gain.
Accordingly, the present invention has been made in view of the above problems occurring in the prior art, and an object of the present invention is to provide an antenna using a complex structure in which dielectric substances having a low dielectric constant and magnetic substances having a high magnetic permeability are arranged in periodic grating arrangement in order to improve the gain, efficiency, and bandwidth of the antenna while maintaining a small size which is an advantage of a conventional antenna using dielectric substances having a high dielectric constant.
To achieve the above object, the present invention provides an antenna using a complex structure having a periodic grating structure of dielectric substances and magnetic substances, including a substrate and a radiation patch formed on the substrate. The substrate is formed of a plurality of columns, each of the columns has the dielectric substances and the magnetic substances of a bar shape alternately disposed therein, and the dielectric substances and the magnetic substances of each column are disposed to cross each other so that long axes of the dielectric substances and the magnetic substances are perpendicular to each other.
Furthermore, to achieve the above object, the present invention provides an antenna using a complex structure having a periodic grating structure of dielectric substances and magnetic substances, including a substrate and a radiation patch formed on the substrate. The substrate includes a plurality of layers, each of the layers has the dielectric substances and the magnetic substances of a regular hexahedron shape alternately disposed therein, and the dielectric substances and the magnetic substances are alternately laminated even in a height direction of the substrate.
Preferably, the antenna resonates in multiple bands.
Furthermore, the dielectric substances and the magnetic substances have the cross section of a regular quadrilateral, and the length of each of faces of the dielectric substances and magnetic substances is 5 mm or 10 mm.
More preferably, the dielectric substances have a dielectric constant of 2.2 and a magnetic permeability of 1.0, and the magnetic substances has a dielectric constant of 16 and a magnetic permeability of 16.
Furthermore, the present invention provides a wireless terminal apparatus comprising the above antenna.
As described above, the present invention provides an antenna using a complex structure in which dielectric substances having a low dielectric constant and magnetic substances having a high magnetic permeability are arranged in periodic grating arrangement in order to improve the gain, efficiency, and bandwidth of the antenna while maintaining a small size which is an advantage of a conventional antenna using dielectric substances having a high dielectric constant.
In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the implementation of the present invention, the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings need to be referred to.
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Referring to
It is preferred that the dielectric substances 110 include dielectric substances of a low dielectric constant, with a dielectric constant of 2.2 and a magnetic permeability of about 1.0, and the magnetic substances 120 include magnetic substances of a high magnetic permeability, with a dielectric constant of 16 and a magnetic permeability of about 16.
For example, the radiation patch 200 may be 170 mm*170 mm in dimension, and the total dimension of the first substrate 100 may be 300 mm*300 mm*20 mm.
The operational characteristics of the antenna according to the first embodiment of the present invention having the above configuration is described below with reference to drawings below and tables.
More particularly,
In each of the cases in which the dielectric substances and the magnetic substances are vertically arranged, the total length of the first substrate 100 having the multi-vertical and periodic structure is 300 mm as described above, and the layers have the same cycle.
In the above case, it can be seen that a multi-band antenna can be implemented and a high gain and efficiency and a wide bandwidth can be achieved.
From
Table 1 shows a comparison of the two kinds of configurations disclosed in
Here, comparison data is calculation results of a bandwidth, a gain, and efficiency for a first resonance frequency. From Table 1, it can be seen that the two kinds of configurations according to the first embodiment have an improved bandwidth, gain, and efficiency in the same antenna size, as compared with the patch antenna using dielectric substances having a high dielectric constant. Furthermore, various resonance frequencies may be obtained by changing a feed power location for each vertical and periodic grating arrangement.
As described above, according to the first embodiment of the present invention, the antenna having a reduced size and having an improved gain, efficiency, and bandwidth and various resonance frequencies can be designed using the complex structure in which the dielectric substances of a low dielectric constant and the magnetic substances of a high magnetic permeability are arranged vertically and periodically.
Referring to
It is preferred that the dielectric substances 110 include dielectric substances of a low dielectric constant, with a dielectric constant of 2.2 and a magnetic permeability of about 1.0, and the magnetic substances 120 include magnetic substances of a high magnetic permeability, with a dielectric constant of 16 and a magnetic permeability of about 16.
For example, the radiation patch 200 may be 170 mm*170 mm in dimension, and the total dimension of the second substrate 300 may be 300 mm*300 mm*20 mm.
The operational characteristics of the antenna according to the present invention having the above configuration is described below with reference to drawings below and tables.
More particularly,
The total length of the second substrate 300 having the multi-grating periodic structure is 300 mm as described above, and the layers have the same cycle.
In the above case, it can be seen that a multi-band antenna can be implemented and a high gain and efficiency and a wide bandwidth can be achieved.
From
Table 2 shows a comparison of the two kinds of configurations disclosed in
Here, comparison data is calculation results of a bandwidth, a gain, and efficiency for a first resonance frequency. From Table 2, it can be seen that the two kinds of configurations according to the second embodiment have an improved bandwidth, gain, and efficiency in the same antenna size, as compared with the case where dielectric substances of a high dielectric constant are used. Furthermore, various resonance frequencies may be obtained by changing a feed power location for each multi-grating periodic structure.
As described above, according to the second embodiment of the present invention, the antenna having a reduced size, an improved gain, efficiency, and bandwidth, and various resonance frequencies can be designed using a complex structure in which the dielectric substances of a low dielectric constant and the magnetic substances of a high magnetic permeability are arranged in multi-grating periodic arrangement.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, they are only illustrative. Those skilled in the art will appreciate that various modifications are possible.
Accordingly, the true technical scope of the present invention should be defined by the technical spirit of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2008-0069886 | Jul 2008 | KR | national |
| 10-2008-0069887 | Jul 2008 | KR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/KR09/04014 | 7/20/2009 | WO | 00 | 4/18/2011 |
