The present invention relates to ceramic chip antennas. More particularly, the invention relates to a mobile communication terminal for transmitting and receiving high frequency signals and a surface mountable ceramic chip antenna terminal to be utilized for various wireless communications.
Conventionally, in order to accommodate the transmission and receiving frequency bands of a mobile communication system, a whip antenna that has a broad bandwidth was mainly used for a mobile phone.
However, the whip antenna takes up a large space and is liable to be broken due to its protruding shape from the mobile phone case. Also, along with the development towards a smaller and lighter mobile phone, the necessity has arisen for a small antenna that has a broad bandwidth but takes up a smaller space.
FIG. 1 shows a diagram of a conventional dipole antenna. As shown in FIG. 1, the conventional dipole antenna has a structure where two dipoles 10, 12 are connected together. The length of each dipole corresponds to xc2xc of resonance frequency wavelength xcex. This type of dipole antenna can easily be manufactured due to its simple structure and also has an advantage of being able to use in a broad frequency band. However, the applications of this type of antenna to a mobile terminal are not easy since it is not portable due to its long length.
FIG. 2 shows a diagram of a conventional helical antenna. As shown in FIG. 2, the conventional helical antenna has a shape where a length of wire 22 is wound around a base rod 20. This is to determine the resonance frequency band by adjusting the number of windings and the space between each winding. This type of helical antenna can be adapted to a mobile terminal since the total length of the antenna is shorter than that of the dipole antenna.
FIG. 3 shows a projection diagram of a ceramic chip antenna. As shown in FIG. 3, a spiral shape helical conductor is included in the conventional ceramic chip antenna structure. The helical conductor comprises a horizontal strip line 34 which is printed in parallel with the lower face 32 and a vertical strip wire 36 formed by conducting paste which fills in a via hole which was vertically formed on the lower face.
The development of this type of ceramic chip antenna 30 has progressed up to a stage where it can be built-in inside a mobile terminal; however, the problem of not being able to perform various types of wireless communication services due to its narrow frequency bandwidth still remains.
The object of the present invention is to reinforce the weakness of a whip antenna by forming a helical conductor in the shape of a dipole structure inside of a ceramic chip as well as to improve the gain, radiation and bandwidth characteristics of the antenna.
Another object of the present invention is to provide a ceramic chip antenna with broadband characteristics which can be built-in inside of a mobile terminal by minimizing the size of the antenna using a helical conductor or high permittivity dielectrics.
In order to achieve the stated objects above, the ceramic chip antenna according to the present invention comprises a main body 100 in which first, second and third dielectric body sheets 100a, 100b, 100c are laminated, first and second horizontal metallic patterns 112, 114 formed on the inner upper face of the main body 100, third and fourth horizontal metallic patterns 116, 118 formed on the inner lower face of the main body 100, and first, second, third and fourth vertical metallic patterns 122, 124, 126, 128 formed on the side face of the main body 100 which connects the first and second horizontal metallic patterns 112, 114 and the third and fourth horizontal metallic patterns 116, 118.