WO2007097532A1

WO2007097532A1 - Unified antenna for receiving the radio and t-dmb signal

Info

Publication number: WO2007097532A1
Application number: PCT/KR2007/000596
Authority: WO
Inventors: Young-Sik Kim; Sang-Won Lee; Yong-Ki Lee
Original assignee: Vehicle System Inc.
Priority date: 2006-02-21
Filing date: 2007-02-05
Publication date: 2007-08-30

Abstract

Disclosed is a unified antenna for radio broadcast and terrestrial DMB, comprising: a substrate installed at a lower part, a antenna part including a radio broadcast antenna for receiving a radio broadcast signal and a terrestrial DMB antenna for receiving a terrestrial DMB signal, which are coaxially arranged as an outer antenna and an inner antenna, respectively, and a dielectric isolator disposed between the radio broadcast antenna and the terrestrial DMB antenna for maintaining a non-contact state between the radio broadcast antenna and the terrestrial DMB antenna, and a casing for receiving the antenna part therein. According to the present invention, the radio broadcast antenna and the terrestrial DMB antenna are unified to have high signal- receiving efficiency and small size.

Description

UNIFIED ANTENNA FOR RECEIVING THE RADIO AND T-

DMB SIGNAL

Technical Field

[1] The present invention relates to a unified antenna. More particularly, the present invention relates to a unified antenna in which an antenna for receiving radio broadcast signals and an antenna for receiving Terrestrial Digital Multimedia Broadcast (TDMB) signals are combined and which is generally installed in automobiles. Background Art

[2] Typically, an antenna for AM/FM radio broadcast has been a pole-type road antenna having the high signal-receiving efficiency, and it has been used by being installed outside an automobile. The pole-type road antenna has good signal-receiving efficiency but has drawbacks of having poor safety and appearance. For such reason, recently a glass antenna is widely being used.

[3] With starting of service of Digital Multimedia Broadcast (DMB), antennae for

DMB have been developed and spread. DMB is classified into Terrestrial DMB (T-DMB) and Satellite DMB (S-DMB) according to the signal transmission method. From the viewpoint of the basic operation method, the former is a method in which a broadcast center sends a broadcast signal to a broadcast transmission tower and then the broadcast signal is sent to individual terminals from the broadcast transmission tower, and the latter is a method in which a broadcast signal is sent using a satellite residing outside the Earth's atmosphere in the form of high-frequency signal.

[4] Such DMB signal can be received using a portable terminal such as cellular phone or a DMB terminal. Accordingly a variety of contents such as high quality voice, graphic, image and data can be serviced to users, resulting in realization of unified service of communication and broadcast. Thus, demand for antennae such as T-DMB antenna and S-DMB antenna as well as for radio broadcast antennae will increase.

[5] However, there is a problem in that since the above-stated functional antennae are individually supplied and installed, installation is inconvenient and cost efficiency is low. Further, due to a large number of antennae installed in an automobile, the automobile would have bad appearance. In particular, in the case of broadcast using a low frequency band, such as radio broadcast and terrestrial DMB, since an antenna must have a sufficient length in order to achieve optimum signal-receiving efficiency, a user actually prefers not to install the antenna on his or her automobile due to the size of the antenna.

[6] In order to sole this problem, a unified antenna is suggested and it is disclosed in Korean Laid-Open Patent Publication No. 2005-47832. The unified antenna has a casing having a center part protruding downward and wing parts extended respectively from left and right side surfaces of the center part, and a public broadcast signal receiver, a GPS receiver and a PCS receiver are installed in the casing on the same plane. The disclosed unified antenna is not more than an assembled module in which several kinds of antennae are randomly arranged on the same plane without concern to signal-receiving efficiencies of the antennae, and then simply assembled. Disclosure of Invention Technical Problem

[7] Accordingly, the present invention has been devised in consideration of the aforementioned problems and conditions, and it is an object of the present invention to provide a unified antenna which functions as a radio broadcast antenna and a DMB antenna. The DMB antenna is limited to a T-DMB antenna for receiving terrestrial DMB signal. This is because the radio broadcast antenna and the T-DMB antenna can be designed to have the same shape and the same orientation due to low frequency band and orientation characteristic.

[8] It is an object of the present invention to provide a unified antenna which unifies a radio broadcast antennae and a T-DMB antenna therein. The unified antenna according to the present invention is improved in aspects of the overall size and length in comparison with conventional ones. The unified antenna according to the present invention has low air resistance.

Technical Solution

[9] In order to achieve the above described advantageous effects and objects, in accordance with the present invention, there is provided a unified antenna for radio broadcast and terrestrial DMB, comprising: a substrate installed at a lower part, an antenna part including a radio broadcast antenna for receiving a radio broadcast signal and a terrestrial DMB antenna for receiving a terrestrial DMB signal, which are coaxially arranged as an outer antenna and an inner antenna, respectively, and a dielectric isolator disposed between the radio broadcast antenna and the terrestrial DMB antenna for maintaining a non-contact state between the radio broadcast antenna and the terrestrial DMB antenna, and a casing for receiving the antenna part therein.

[10] The antenna part is not two-dimensionally installed but installed to incline with respect to the substrate at a predetermined angle in order to enhance signal-receiving efficiency according to orientation characteristics. The terrestrial DMB antenna also can function as an analog TV broadcast antenna for receiving an analog signal of TV broadcast.

[11] The unified antenna according to the present invention is not inferior in signal- receiving efficiency to individual antennae, and has remarkably improved characteristics of size, particularly length. The features and advantages described above or not mentioned above will be more apparent with embodiments which will be described below with reference to the accompanying drawings.

Advantageous Effects

[12] As can be seen through the embodiment of the present invention, the antennae according to the present invention remarkably improves the overall size, particularly the length, without degrading the signal-receiving efficiency in comparison with conventional ones. Features and advantages which are described or not described above may be apparent with reference to the following embodiments described with reference to the accompanying drawings.

Brief Description of the Drawings

[13] FIG. 1 is a perspective view illustrating an antenna according to a first embodiment of the present invention;

[14] FIG. 2 is an exploded perspective view illustrating the antennae shown in FIG. 1;

[15] FIG. 3 is a cross-sectional view illustrating the assembled antenna shown in FIG. 2;

[16] FIG. 4 is a circuit diagram illustrating a tuning circuit of the antennae for receiving a terrestrial DMB signal shown in FIG. 1 ; [17] FIG. 5 is a graph illustrating the receiving characteristic of a terrestrial DMB signal of the antenna according to the first embodiment; [18] FIG. 6 is a graph illustrating the signal receiving characteristic of a terrestrial DMB- use-only antenna; [19] FIG. 7 is a graph illustrating the receiving characteristic of a radio broadcast signal of the antenna according to the first embodiment;

[20] FIG. 8 is a graph illustrating the signal receiving characteristic of a radio broadcast- use-only antenna; [21] FIG. 9 is a perspective view illustrating an antenna according to a second embodiment of the present invention; [22] FIG. 10 is a graph illustrating the signal receiving characteristic of the antenna according to the second embodiment of the present invention; and [23] FIG. 11 is a graph illustrating the signal receiving characteristic of the antenna without a matching device, according to the second embodiment of the present invention.

[24] <Brief Description of Key Elements in the Drawings>

[25] 10, 10a: Unified antenna 11: Substrate

[26] 12, 12a: Antenna part 13: Casing

[27] 14: Connection means 15: Radio broadcast antenna [28] 16: Terrestrial DMB antenna 17: Body part

[29] 18: Wing part 19: Isolate

[30] 20: Matching device

Best Mode for Carrying Out the Invention

[31] With reference to FIG. 1 through FIG. 3, reference symbol 10 denotes a unified antenna according to an embodiment of the present invention. The unified antenna 10 comprises a substrate 11, an antenna part 12 installed on the substrate 11, and a casing 13 encasing the substrate 11 and the antennae part 12.

[32] The substrate is provided at the bottom of the casing 13 and is a dielectric plate having a ground part on the lower surface thereof and a power supply point at a center portion of the upper surface thereof. The substrate 11 includes a connection means 14 installed at a center portion of the upper surface thereof and has a structure which couples the antenna part 12. The connection means is a bracket in which the antenna 12 is inserted.

[33] The antenna part 12 includes an AM/FM radio broadcast antenna 15 and a terrestrial DMB antenna 16. The antennae 12 and 15 are unified in the antenna 12 in a manner such that the terrestrial DMB antenna 16 is disposed inside the radio broadcast antenna 15 in order to decrease the overall area taken up by the antenna 12 and reduce the thickness of the antennae 12 for the purpose of minimizing air resistance. That is, the antenna 12 includes the radio broadcast antenna 15 and the terrestrial DMB antenna 16 which are coaxially arranged as an outer crust and an inner crust, respectively. The radio broadcast antenna 15 is a coil- type helical antenna.

[34] The radio broadcast antenna 15 and the terrestrial DMB antenna 16 must be arranged in a manner such that they are not in contact with each other, that is, they are distanced from each other. However, since the coaxial arrangement possibly causes them to be in contact with each other. Accordingly, a dielectric isolator 19 is installed in order to maintain the non-contact state between the antennae 15 and 16. In the drawings, the isolator 19 is installed in a manner such that an end of the terrestrial DMB antenna 16 installed inside the antenna 15 penetrates the isolator 19, but the structure of the isolator can be modified diversely.

[35] Preferably, the terrestrial DMB antenna 16 also functions as an analog TV broadcast antenna for receiving an analog signal of TV broadcast. In this case, for example, as shown in FIG. 4, a tuning circuit is provided. The tuning circuit includes an RF amplifier 1 for amplifying a signal received in the antenna 16, impedance matching circuits 4 and 5 for matching the amplified signal and supplying the matched signal to a TV tuner 2 and a DMB tuner 3, the impedance matching circuits 4 and 5 being connected in parallel with each other. That is, by using the tuning circuit, the antenna 16 can receive both of an analog TV broadcast signal and a terrestrial DMB signal. However, the tuning circuit is the specific feature of the antenna according to the present invention.

[36] The antenna part 12 is arranged on the plane of the substrate 11, but is arranged in a manner such that it inclines against the surface of the substrate 11 at a predetermined angle in order to increase signal-receiving efficiency according to orientation characteristics of the antennae 15 and 16. The inclination angle may be in the range from 40 to 60 degrees, in consideration of air resistance when the antenna 10 is installed on an automobile.

[37] The unified antenna part 12 is installed in a manner such that an end thereof is inserted into the connection means 14 provided on the upper surface of the substrate 11, and is extended, inclining backward. The antenna part 12 of the antenna 10 according to the present embodiment is fixed using the connection means 14 by a way of insertion, but the antenna fixing method is not limited thereto. That is, the antenna can be fixed in other ways.

[38] In the above description, it is explained that the casing 13 encases the substrate 11 and the antenna part 12, but it can encase only the antenna part 12 in the case in which the substrate 11 and the antenna part 12 are separated from each other. The casing 13 is designed in a manner such that it reduces air resistance when the antenna is installed on an automobile. The casing 13 comprises a body part 17 and a wing part 18. The body part 17 receives the substrate 11 and the connection means 14 therein and the wing part 18 receives the antenna part 12 having an end coupled to the connection means 14 in inclining manner therein.

[39] The body part 17 has a streamlined shape like a body of an airplane, and the wing part 18 has the structure similar to a tail fin of an airplane. That is, thickness thereof decreases toward a rear end thereof and a contour thereof is sloped up toward the rear end thereof. Thanks to the above-described structure, air resistance is minimized when the antenna 10 is installed on an automobile. Even though it is now shown in the drawings, a radio broadcast-receiving connector, a terrestrial DMB -receiving connector and an analog TV broadcast-receiving connector are provided on the rear surface of the body pat 17.

[40] According to the embodiment, the terrestrial DMB antenna 16 for receiving a terrestrial DMB signal, which is 7 millimeters in diameter and 100 millimeters in length, and the radio broadcast antenna 15 for receiving a radio broadcast signal, which is 12 millimeters in diameter and 155 millimeters in length are prepared, coaxially arranged, and assembled, producing the antenna 10.

[41] Then, a terrestrial DMB -only antenna with diameter of 7 millimeters and length of

155 millimeters for receiving only a terrestrial DMB signal, and a radio broadcast-only antenna with diameter of 12 millimeters and length of 195 millimeters for receiving only a radio broadcast signal, are separately prepared. Then, the characteristics of the unified antenna 10 and the conventional antennae are compared. For reference, the conventional antennae and the antennae 15 and 16 of the antenna part 12 of the antenna 10 according to the present invention are made of the same material. The lengths of the antennae are determined to have optimum signal-receiving efficiency.

[42] As shown in FIG. 5, FIG. 6 and FIG. 7, the unified antenna 10 exhibits the same or superior signal-receiving efficiencies of terrestrial DMB and radio broadcast over the overall frequency bands as or to the individual antennae. That is, the unified antenna 10 exhibits the same or superior efficiency as or to the individual antennae with length which is about 70% of the length of the individual antennae. This is due to the peculiar unification characteristic of the unified antenna 10.

[43] With reference to FIG. 9, the unified antenna 10a according to another embodiment of the present invention further includes a matching device 20 in addition to elements of the unified antenna 10 according to the previous embodiment of the present invention. In detail, an antenna part 12a of the unified antenna 10a includes a coil-type matching device 20 coaxially arranged outside the radio broadcast antenna 15 and having respective ends connected to the radio broadcast antenna 15.

[44] According to the present embodiment, the antenna 10a is manufactured by arranging coaxially the matching device 20 having diameter of 18 millimeters and length of 60 millimeters outside the radio broadcast antenna 15. Then, characteristics of the unified antenna 10a with the matching device 20 and the unified antenna 10 without the matching device 20 are compared.

[45] As shown in FIG. 10 and FIG. 11, the antennae 10 and 10a shows similar characteristics over a frequency band of 88 to 108MHz which is the frequency band of FM radio broadcast, but the antenna 10a shows superior and uniform gain characteristic to the unified antenna 10 over a frequency band of 180 to 210 MHz which is the frequency band of terrestrial DMB.

Claims

[1] A unified antenna for radio broadcast and terrestrial DMB, comprising: a substrate installed at a lower part, an antenna part including a radio broadcast antenna for receiving a radio broadcast signal and a terrestrial DMB antenna for receiving a terrestrial DMB signal, which are coaxially arranged as an outer antenna and an inner antenna, respectively, and a dielectric isolator disposed between the radio broadcast antenna and the terrestrial DMB antenna for maintaining a non-contact state between the radio broadcast antenna and the terrestrial DMB antenna, and a casing for receiving the antenna part therein.

[2] The unified antenna for radio broadcast and terrestrial DMB according to claim

1, wherein the terrestrial DMB antenna also functions as an analog TV broadcast antenna for receiving an analog signal of TV broadcast.

[3] The unified antenna for radio broadcast and terrestrial DMB according to claim

1, wherein a connection means to which the antenna part is coupled is installed on an upper surface of the substrate.

[4] The unified antenna for radio broadcast and terrestrial DMB according to claim

1, wherein the casing has a streamlined body for receiving the substrate therein and a wing provided at a rear portion of the body for receiving the antenna part therein, the wing having a structure in which thickness thereof is decreased toward a rear end thereof and the uppermost contour is sloped up toward the rear end thereof.

[5] The unified antenna for radio broadcast and terrestrial DMB according to claim

1, wherein the radio broadcast antenna is a coil-type helical antenna.

[6] The unified antenna for radio broadcast and terrestrial DMB according to claim

1, wherein the antenna part is installed to be tilted with respect to the upper surface of substrate.

[7] The unified antenna for radio broadcast and terrestrial DMB according to claim

1, further comprising a coil-type matching device coaxially arranged outside the radio broadcast antenna and having respective ends connected to the radio broadcast antenna.