EP2065974A1

EP2065974A1 - Multiband antenna of gap filler system

Info

Publication number: EP2065974A1
Application number: EP08162139A
Authority: EP
Inventors: Sung Min Han; Joon Gyu Ryu; Dae Ig Chang; Ho Jin Lee
Original assignee: Electronics and Telecommunications Research Institute ETRI
Current assignee: Electronics and Telecommunications Research Institute ETRI
Priority date: 2007-11-20
Filing date: 2008-08-11
Publication date: 2009-06-03
Also published as: KR100952979B1; KR20090051866A

Abstract

A multiband antenna includes a dielectric material (111) and patches (113,114). The patches are formed on the dielectric material, and a slot (115) is formed between two adjacent patches. The number of slots is determined corresponding to the number of frequency bandwidths output by the multiband antenna.

Description

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a multiband antenna of a gap filler system.
This work was supported by the IT R&D program of MIC/IITA [2005-S-404-23, Research and development on 3G long-term evolution access system].

(b) Description of the Related Art

Satellite broadcasting or satellite communication may be received or communicated when a line of sight (LOS) condition is fulfillled. Recently, some satellite broadcasting systems such as the satellite digital multimedia broadcasting (DMB) have adopted the gap filler technology so as to receive satellite broadcasting under a non-LOS condition.
A gap filler system using the gap filter technology functions as a small-output repeater station for receiving radio waves from a transmitter station and repeating the received radio waves such that broadcasting can be received in a blanket area where the radio waves are intercepted by tall buildings under the satellite broadcasting or mobile communication condition. For example, in the direct broadcast satellite (DBS) system, a small-output repeater station is installed on the roof of a building and thereby repeats the radio waves that are output by a terrestrial transmitter station or a satellite so that a moving object may receive a high quality of sound signals in the blanket area by using the characteristic of orthogonal frequency division multiplexing (OFDM) of the multi-carrier modulation system. In this instance, the gap filler system uses a Yagi antenna, a multilayer antenna, and a patch array antenna for amplifying signals within a single frequency bandwidth.
The at least one antenna used for the gap filler system is restricted to satellite broadcasting, it performs transmission through amplification of received signals or conversion of frequencies in a single direction and has no concept of bi-directional communication, and hence cannot be used for the bi-directional satellite communication environment.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a multiband antenna for bi-directional communication.
An exemplary embodiment of the present invention provides a multiband antenna including a dielectric material, and a plurality of patches arranged on the dielectric material, wherein a slot is formed between two adjacent patches from among the plurality of patches, and the number of output frequency bandwidths corresponds to the number of slots.
Another embodiment of the present invention provides, a multiband antenna including a dielectric material, a first patch formed on the dielectric material and including a feeding point, and a second patch formed on the dielectric material and surrounding the first patch, wherein a slot is formed between the first patch and the second patch.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a gap filler system and a terminal according to an exemplary embodiment of the present invention.
FIG. 2 shows a frequency bandwidth used for a gap filler system shown in FIG. 1.
FIG. 3 shows a dual band antenna among a multiband antenna according to an exemplary embodiment of the present invention.
FIG. 4A shows a structure of a general single band antenna.
FIG. 4B to FIG. 4D show structures of a multiband antenna according to an exemplary embodiment of the present invention.
FIG. 5A and FIG. 5B show linear polarization of a multiband antenna according to an exemplary embodiment of the present invention.
FIG. 6A to 6D show circular polarization of a multiband antenna according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.
Through the specification, unless explicitly described to the contrary, the word "comprise" and variations such as "comprises" or "comprising" will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.
Referring to FIG. 1 and FIG. 2, a gap filler system according to an exemplary embodiment of the present invention will now be described.
FIG. 1 is a schematic diagram of a gap filler system and a terminal according to an exemplary embodiment of the present invention, and FIG. 2 is a frequency bandwidth used for a gap filler system shown in FIG. 1.
Referring to FIG. 1, a gap filler system 100, a terminal 200 communicating with a gap filler system 100, and a user terminal 300 connected to the gap filler system.
The gap filler system 100 includes a multiband antenna 110 for receiving signals, for example satellite communication signals of the Ka band (about 20-30GHz) or broadcasting signals of the Ku band (about 12-18GHz). The gap filler system 100 is fixedly installed in the wide non-LOS environment such as a subway, tunnel, and mountain, etc., it changes frequency of the transmitted signal and it transmits the resultant signal to the terminal 200.
For example, the gap filler system 100 changes the received satellite communication signals or the received broadcasting signals into the industrial scientific medical (IMS) bandwidth shown in FIG. 2, and transmits the changed signals to the terminal 200. In this instance, the ISM bandwidth shown in FIG. 2 includes a first frequency bandwidth (about 2455-2477MHz), a second frequency bandwidth (about 5732-5768MHz), and a third frequency bandwidth (about 5814-5850MHz). The first to third frequency bandwidths changed in the gap filler system 100 according to the exemplary embodiment of the present invention are frequency bandwidths from about 2.4GHz to about 5.85GHz among the ISM bandwidth. The frequency bandwidths are set for testing the multiband antenna 110, but are limited thereto. That is, The first to third frequency bandwidths changed in the gap filler system 100can be set to other values according to the frequency bandwidth generated in the multiband antenna 110.
The terminal 200 is installed in a vehicle such as a car or a train, it transmits signals such as the satellite communication signals or the broadcasting signals from the gap filler system 100 to a service user 300, and it includes an antenna 210 for transmitting/receiving the signals.
The user terminal 300 includes a notebook computer 310, a personal digital assistant (PDA) 320, and a multimedia terminal 330 that are available for the wireless local area network (WLAN) and the wireless broadband Internet (Wibro), it receives the satellite communication signals or the broadcasting signals from the terminal 200, and it uses various services including wireless Internet, mobile games, video education, and tourist information.
Referring to FIG. 3 to FIG. 6, a dual band antenna 110 of a gap filler system according to an exemplary embodiment of the present invention will now be described.
FIG. 3 shows a dual band antenna among multiband antennas according to an exemplary embodiment of the present invention, FIG. 4A shows a structure of a general single band antenna, and FIG. 4B to FIG. 4D show structures of a multiband antenna according to an exemplary embodiment of the present invention. FIG. 5A and FIG. 5B show linear polarization of a multiband antenna according to an exemplary embodiment of the present invention, and FIG. 6A to 6d show circular polarization of a multiband antenna according to an exemplary embodiment of the present invention.
The multiband antenna 110 is a multiband antenna having a single feeding point, and its basic form is similar to a microstrip or a dielectric material patch antenna.
As shown in FIG. 3, a dual band antenna from among the multiband antennas 110 includes a dielectric material 111, a feeding point 112, patches 113 and 114, a slot 115, and a ground voltage (not shown).
The patches 113 and 114 are separately arranged on the dielectric material 111, and the patch 114 surrounds the patch 113. Here, a portion of the dielectric material 111 exposed between the patch 113 and the patch 114 functions as a slot 115. In this embodiment, the slot 115 functions a capacitor. The patch 113 includes the feeding point 112.
In this instance, when a signal for configuring a high frequency bandwidth is transmitted to the feeding point 112, the patch 113 is resonated with a high frequency. When a signal for generating a low frequency bandwidth is transmitted to the feeding point 112, the signal is resonated by the patch 113 and the resonated signal is transmitted to the patch 114 through the slot 115 functioning as a capacitor. Thereby, the patches 113 and 114 are resonated to form a signal with a low frequency based on the coupling signal.
The number of slots 115 formed on the dielectric material 111 is defined by the frequency bandwidths for forming, as shown in FIG. 4A to FIG. 4D.
FIG. 4A shows a single band antenna that dose not have a slot. The single band antenna includes a patch 113 formed on a dielectric material (not shown) and a feeding point 112a formed on the patch 113a. As described, the single band antenna forms a single frequency band, and hence, no slot is formed.
FIG. 4B shows a dual band antenna having two patches 113b and 114b and a slot 115b which is formed between the two patches 113b and 114b, and thereby forms two frequency bandwidths. Thereby, when a signal for forming a higher frequency bandwidth is transmitted, a signal with the higher frequency bandwidth is generated by the resonation operation of the patch 113b, and when a signal for forming a lower frequency bandwidth is transmitted, a signal with the lower frequency bandwidth is generated by the resonation operation of the patch 114b.
FIG. 4C shows a triple band antenna having three patches 113c, 114c, and 116c and two slots 115c and 117c, and thereby forms three frequency bandwidths. One slot 115c is formed between the patches 113c and 114c and another slot 117c is formed between the patches 114c and 116c.
FIG. 4D shows a quad band antenna having four patches 113d, 114d, 116d, and 118d and three slots 115d, 117d, and 119d, and thereby forms four frequency bandwidths. The slot 115d is formed between the patches 113d and 114d, the slot 117d is formed between the patches 114d and 116d, and the slot 119d is formed between the patches 116d and 118d.
Like FIG. 4a, in FIG. 4C and FIG. 4D, as the magnitude of the frequency bandwidth for generating becomes less, the number of patches for resonating increases. For example, when a signal for forming the highest frequency bandwidth is transmitted, only the patch 113c or 113d is resonated, and when a signal for forming the lowest frequency bandwidth is transmitted, the patches 113c, 114c, and 116 or 113d, 114d, 116d, and 118d are resonated.
At this time, as a distance from the feeding point becomes larger, that is, the number of resonated patches becomes larger, the magnitude of the resonated frequency decreases. For example, in FIG. 4B to FIG. 4D, among the resonated frequencies, the largest frequency is resonated by the patch 113b, 113c, or 113d, and the smallest frequency is resonated by the patch 114b, 116c, or 118d.
The multiband antenna according to the exemplary embodiment of the present invention forms the number of slots that is less than that of the frequency bandwidths to be formed by 1.
In this instance, since the slot that is added according to the frequency bandwidth functions as a capacitor, the size of the antenna can be reduced. For example, when the sizes of the patches 113a, 113b and 114b used for forming a frequency bandwidth are compared in the single band antenna shown in FIG. 4A and the dual band antenna shown in FIG. 4B, it is known that the patch 113b of the dual band antenna is formed to be smaller than the patch 113a of the single band antenna even considering the size of the slot 115b and the permittivity of the dielectric material provided between the ground voltage and the patches.
Since the signals that is actually used in the gap filler system 100 are the Ka band (about 20-30GHz) satellite communication signals and the Ku band (about 12-18GHz) broadcasting signals, the multiband antenna 110 according to the exemplary embodiment of the present invention is the dual band antenna, the triple band antenna, or the quad band antenna, as shown in FIGs. 4B to 4D. Alternatively, the gap filler system 100 may include the multiband antenna for forming frequency bandwidths greater than the quad band antenna according to the used signal.
As described, the multiband antenna 110 controls frequency generation of the multiband by controlling the signal that is transmitted to the feeding point 112 or 112a-112d. According to the exemplary embodiment of the present invention, the propagation of the multiband antenna 110 is determined by the shape of the patches.
As shown in FIG. 5A, linear polarization and vertical polarization can be formed when the feeding point 112a' is formed out of the origin on the vertical axis passing through the center of the rectangle patch 113a'.
As shown in FIG. 5B, linear polarization and horizontal polarization can be formed when the feeding point 112b' is formed out of the origin on the horizontal axis passing through the center of the rectangle patch 113b'.
As shown in FIG. 6A and FIG. 6B, right-hand circular polarization or left-hand circular polarization of the circular polarization can be formed when the feeding points 112c' and 112d' are formed out of the origin on the vertical line passing through the center of the square patches 113c' and 113d' with two edges cut off, respectively.
Further, as shown in FIG. 6C and FIG. 6D, the right-hand circular polarization and the left-hand circular polarization of the circular polarization can be formed when the feeding points 112e' and 112f are formed on the diagonal of the squared patches 113e' and 113f, respectively,
The multiband antenna according to the exemplary embodiment of the present invention transmits/receives the multiband frequency in the bi-directional manner by using the feeding point.
According to an exemplary embodiment of the present invention, a multiband frequency is generated by adding a slot depending on the frequency bandwidth for changing or generating a patch form of a multiband antenna, and a plurality of systems requiring the multiband is combined by applying the present invention to linear polarization and circular polarization. The multiband antenna can generate a multi-frequency bandwidth when a slot corresponding to the frequency bandwidth is added or the shape of the patch is changed, and it is easily applied to the linear polarization and circular polarization to be thus used for various systems requiring multibands.
Further, the multiband antenna according to the exemplary embodiment of the present invention is realized as a microstrip antenna to thus allow mass production, and it allows down-sizing and a smaller weight by reducing the size to be less than that of a single band antenna.
The above-described embodiments can be realized through a program for realizing functions corresponding to the configuration of the embodiments or a recording medium for recording the program in addition to through the above-described device and/or method, which is easily realized by a person skilled in the art.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various medications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

A multiband antenna comprising:
a dielectric material; and

a plurality of patches arranged on the dielectric material,
wherein a slot is formed between two adjacent patches from among the plurality of patches, and
the number of output frequency bandwidths corresponds to the number of slots.
The multiband antenna of claim 1, wherein the number of slots is less than the number of frequency bandwidths by 1.
The multiband antenna of claim 1 or 2, wherein a first patch from among two adjacent patches surrounds the second patch.
The multiband antenna of claim 3, wherein the multiband antenna comprises a feeding point formed on an innermost patch from among the plurality of patches and receiving a signal for forming the frequency bandwidth.
The multiband antenna of claim 4, wherein the first patch is resonated by a first frequency, and the second patch is resonated by a second frequency that is higher than the first frequency.
The multiband antenna of claim 5, wherein the first patch receives a coupling signal of the signal transmitted to the second patch and is resonated by the first frequency.
The multiband antenna of one of claims 1 to 6, wherein the plurality of patches have a shape for forming linear polarization or circular polarization.
A multiband antenna comprising:
a dielectric material;

a first patch formed on the dielectric material and having a feeding point; and

a second patch formed on the dielectric material and surrounding the first patch,
wherein a slot is formed between the first patch and the second patch.
The multiband antenna of claim 8, wherein the first patch is resonated by a first frequency, and the second patch is resonated by a second frequency that is lower than the first frequency.
The multiband antenna of claim 8 or 9, wherein the second patch receives a coupling signal of the signal transmitted to the first patch and is then resonated by a second frequency.
The multiband antenna of claim 8, 9 or 10, further comprising a third patch formed on the dielectric material and surrounding the second patch.