Patent Description:
<CIT> discloses an antenna comprising a split ring resonator. The antenna has a main portion, a feeding portion and at least one radiation element. The main portion forms a split ring. The feeding portion is provided on the main portion. The radiation element extends from the main portion. <CIT> discloses an antenna and an electronic device with the antenna. The antenna comprises a grounding part, a main radiation part and a shield wall, wherein the main radiation part comprises a first radiation part and a second radiation part which are in symmetrical structures, wherein the first radiation part comprises a first feed-in end; the second radiation part comprises a second feed-in end; the main radiation part and the shield wall are respectively connected to the two sides of the grounding part and are opposite to each other. The antenna has two feed-in ends in two different directions, so as to select two coaxial arrangement manners. Referring to <FIG>, a multiband antenna <NUM> disclosed in <CIT> (Patent Document <NUM>) is provided with a slot antenna <NUM> and a radiation element <NUM>.

As shown in <FIG>, a slot <NUM> of the slot antenna <NUM> has a longitudinal direction in a first direction or a Y-direction. The radiation element <NUM> has a first part <NUM> and a second part <NUM>. The first part <NUM> extends from the slot antenna <NUM> in a second direction or an X-direction perpendicular to the first direction. The second part <NUM> extends from an end portion of the first part <NUM> in the first direction. The second part <NUM> is larger than the first part <NUM> in length.

The multiband antenna <NUM> of Patent Document <NUM> has two resonant frequencies or operating frequencies, namely, a resonant frequency of the slot antenna <NUM> and a resonant frequency of the radiation element <NUM>. Here, the second part <NUM> of the radiation element <NUM> extends in the first direction and lowers the resonant frequency of the slot antenna <NUM> in comparison with a case where the radiation element <NUM> is not provided. This means that the use of the radiation element <NUM> can cause downsizing of the slot antenna <NUM> which has a specific resonant frequency.

It is an object of the present invention to provide a multiband antenna which can be downsized by adopting a structure different from that of the multiband antenna of Patent Document <NUM>.

The object is achieved by the multiband antenna according to claim <NUM>.

In the multiband antenna of the present invention, the additional element adjusts an impedance of the multiband antenna, and thereby a resonant frequency of the slot antenna can be lowered. In other words, the additional element can downsize the slot antenna having a specific resonant frequency, so that the multiband antenna can be downsized.

An appreciation of the objectives of the present invention and a more complete understanding of its structure may be had by studying the following description of the preferred embodiment and by referring to the accompanying drawings.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications falling within the scope of the present invention as defined by the appended claims.

Referring to <FIG>, a multiband antenna <NUM> according to an embodiment of the present invention is provided with a conductive main portion <NUM>, a first radiation element (radiation element) <NUM> and an additional element <NUM>. In the present embodiment, the multiband antenna <NUM> is further provided with a second radiation element (additional radiation element) <NUM> and a grounding terminal <NUM>. However, in the present invention, the second radiation element <NUM> and the grounding terminal <NUM> are not essential. Nevertheless, by providing the second radiation element <NUM>, a bandwidth of the multiband antenna <NUM> can be widened.

As understood from <FIG>, the multiband antenna <NUM> is formed of a single sheet metal. In other words, the multiband antenna <NUM> is formed by punching and bending a single metal sheet. However, the present invention is not limited thereto. The multiband antenna <NUM> may be formed of a plurality of metal sheets. Alternatively, the multiband antenna <NUM> may be formed of a metal foil or a conductive pattern formed on a circuit board instead of the metal sheet at least in part. Furthermore, the multiband antenna <NUM> may be formed of a metal sheet or a metal foil and a supporter which is made of resin and supports the metal sheet or the metal foil if necessary.

As shown in <FIG>, the conductive main portion <NUM> has at least a first slot edge portion <NUM> and a second slot edge portion <NUM>. In the present embodiment, the conductive main portion <NUM> further has a coupling portion <NUM>. The first slot edge portion <NUM>, the second slot edge portion <NUM> and the coupling portion <NUM> are coupled to one another and define a slot <NUM> and an open portion <NUM>. In other words, the conductive main portion <NUM> is formed with the slot <NUM> and the open portion <NUM>.

As understood from <FIG>, the conductive main portion <NUM> is located on a specific plane defined by a first direction and a second direction perpendicular to the first direction. In the present embodiment, the first direction is a Y-direction, and the second direction is an X-direction. Moreover, in the present embodiment, the specific plane is an X-Y plane. The first direction defines a first orientation and a second orientation which is an orientation opposite to the first orientation. In the present embodiment, the first orientation is a negative Y-direction, and the second orientation is a positive Y-direction. Moreover, in the present embodiment, the second direction is also a front-rear direction. A negative X-direction is directed forward while a positive X-direction is directed rearward.

As shown in <FIG>, each of the first slot edge portion <NUM> and the second slot edge portion <NUM> has a rectangular shape long in a first direction. The first slot edge portion <NUM> has an end portion <NUM>, which is oriented in the first orientation of the first direction, and an end portion <NUM>, which is oriented in the second orientation of the first direction. The second slot edge portion <NUM> has an end portion <NUM>, which is oriented in the first orientation of the first direction, and an end portion <NUM>, which is oriented in the second orientation of the first direction.

As shown in <FIG>, the first slot edge portion <NUM> and the second slot edge portion <NUM> are positioned apart from each other in the second direction. The first slot edge portion <NUM> is located forward of the second slot edge portion <NUM>. In the second direction, the slot <NUM> and the open portion <NUM> are located between the first slot edge portion <NUM> and the second slot edge portion <NUM>. Thus, the first slot edge portion <NUM> and the second slot edge portion <NUM> are arranged so that they sandwich the slot <NUM> and the open portion <NUM> therebetween.

As shown in <FIG>, the coupling portion <NUM> has a rectangular shape long in the second direction. The coupling portion <NUM> couples one of the end portions of the first slot edge portion <NUM> to one of the end portions of the second slot edge portion <NUM>. In the present embodiment, the coupling portion <NUM> couples the end portion <NUM> of the first slot edge portion <NUM> and the end portion <NUM> of the second slot edge portion <NUM> to each other.

As shown in <FIG>, the slot <NUM> has a longitudinal direction in the first direction. The open portion <NUM> is located at an end portion of the conductive main portion <NUM>, wherein the end portion of the conductive main portion <NUM> is oriented in the first orientation. In other words, the open portion <NUM> is located between the end portion <NUM> of the first slot edge portion <NUM> and the end portion <NUM> of the second slot edge portion <NUM>. The open portion <NUM> is contiguous to the slot <NUM> and opens the slot <NUM> outside of the conductive main portion <NUM>. In the present embodiment, the open portion <NUM> is opened in the first orientation of the first direction. However, the present invention is not limited thereto. The open portion <NUM> may be opened forward or rearward. Even when the open portion <NUM> is opened forward or rearward, the open portion <NUM> of the present invention is formed at a part of the conductive main portion <NUM> which is different from the first slot edge portion <NUM>.

As shown in <FIG>, the first radiation element <NUM> has a first part <NUM> and a second part <NUM>. The first part <NUM> has a rectangular shape long in the second direction and is located on a specific plane. The first part <NUM> extends in the second direction from the end portion <NUM> of the first slot edge portion <NUM>, wherein the end portion <NUM> is oriented in the first orientation of the first direction. In the present embodiment, the first part <NUM> extends rearward.

As shown in <FIG>, the second part <NUM> of the first radiation element <NUM> extends from a rear end portion of the first part <NUM> in the second orientation of the first direction. In the present embodiment, the second part <NUM> has an upper portion <NUM> and a rear portion <NUM>. The upper portion <NUM> has a rectangular shape long in the first direction and is located on the specific plane. The rear portion <NUM> has a rectangular shape long in the first direction and extends from a rear edge of the upper portion <NUM> in a third direction perpendicular to both the first direction and the second direction. In the present invention, the rear portion <NUM> is not essential. However, the rear portion <NUM> can increase a radiation efficiency of the first radiation element <NUM> without increasing an occupation area of the first radiation element <NUM> when viewed along the third direction. In the present embodiment, the third direction is a Z-direction. Supposing a positive Z-direction is directed upward while a negative Z-direction is directed downward, the rear portion <NUM> extends downward from the upper portion <NUM>.

As shown in <FIG>, the additional element <NUM> extends forward from a lower edge of the rear portion <NUM> of the second part <NUM> of the first radiation element <NUM>. The additional element <NUM> is positioned apart from the conductive main portion <NUM> in the third direction and extends forward without being brought into contact with the conductive main portion <NUM>.

Referring to <FIG>, in the present embodiment, the additional element <NUM> has a rectangular shape. The additional element <NUM> is positioned apart from both ends of the second part <NUM> in the first direction. Moreover, the additional element <NUM> is nearer to an end portion of the second part <NUM>, which is oriented in the second orientation, than to an end portion of the second part <NUM>, which is oriented in the first orientation, in the first direction. However, the present invention is not limited thereto. The shape and the position of the additional element <NUM> may be freely set according to intended antenna properties.

As understood from <FIG>, the additional element <NUM> extends toward a second specific area <NUM> through a first specific area <NUM>. In the present embodiment, the additional element <NUM> extends to the second specific area <NUM>. In other words, the additional element <NUM> overlaps with the second slot edge portion <NUM> when viewed along the third direction. Here, each of the first specific area <NUM> and the second specific area <NUM> is an area on a plane which is perpendicular to the third direction and which is positioned apart from the specific plane in the third direction. In addition, the first specific area <NUM> is an area overlapping with the first slot edge portion <NUM> in the third direction. Moreover, the second specific area <NUM> is an area overlapping with the second slot edge portion <NUM> in the third direction. In the present embodiment, the additional element <NUM> is located on a plane in which the first specific area <NUM> and the second specific area <NUM> are included, and a front edge <NUM> of the additional element <NUM> is in the second specific area <NUM>. However, the present invention is not limited thereto. Each of the first specific area <NUM> and the second specific area <NUM> may be freely set according to intended antenna properties.

As understood from <FIG>, the front edge <NUM> of the additional element <NUM> is located near to the second slot edge portion <NUM>. With this structure, a capacitor is formed between the additional element <NUM> and the second slot edge portion <NUM>. By setting a shape and a size of the additional element <NUM> to give an intended value to a capacitance, an impedance of the multiband antenna <NUM> can be adjusted, and downsizing of the multiband antenna <NUM> can be achieved. Although the additional element <NUM> extends to the second specific area <NUM> in the present embodiment, the additional element <NUM> may not extend to the second specific area <NUM>. However, if an area where the additional element <NUM> and the second slot edge portion <NUM> overlap with each other is larger when viewed along the third direction, larger capacitance can be obtained. Larger capacitance can achieve a lower operating frequency and downsize the multiband antenna <NUM>.

As shown in <FIG>, the second radiation element <NUM> is located on the specific plane and extends from the first radiation element <NUM> in the first orientation. In detail, the second radiation element <NUM> has a long portion <NUM> and a short portion <NUM>. The long portion <NUM> has a rectangular shape long in the first direction. Moreover, the short portion <NUM> has a rectangular shape long in the second direction. The long portion <NUM> extends in the first orientation from the end portion of the second part <NUM> of the first radiation element <NUM>, wherein the end portion of the second part <NUM> is oriented in the first orientation of the first direction. The short portion <NUM> extends forward from an end portion of the long portion <NUM>, wherein the end portion of the long portion <NUM> is oriented in the first orientation of the first direction. However, the present invention is not limited thereto. The second radiation element <NUM> may be formed of only the long portion <NUM>. However, the short portion <NUM> can elongate an electrical length of the second radiation element <NUM> without increasing a size of the second radiation element <NUM> in the first direction.

As shown in <FIG>, the grounding terminal <NUM> has a rectangular shape long in the second direction. The grounding terminal <NUM> extends forward from a front edge of the second slot edge portion <NUM>. In detail, the grounding terminal <NUM> extends forward from a front edge of the end portion <NUM> of the second slot edge portion <NUM>. An edge of the grounding terminal <NUM>, which is oriented in the first orientation of the first direction, is arranged on a straight line with an edge of the second slot edge portion <NUM>, which is oriented in the first orientation of the first direction. However, the present invention is not limited thereto. The shape, the size and the position of the grounding terminal <NUM> may be freely set according to intended properties.

The grounding terminal <NUM> is connected to a host conductor (not shown) when used. The host conductor may be a device case (not shown) which accommodates the multiband antenna <NUM> or a ground pattern of a circuit board (not shown) on which the multiband antenna <NUM> is mounted. By using the host conductor, downsizing of the multiband antenna <NUM> can be achieved.

As shown in <FIG>, the conductive main portion <NUM> is provided with feeding points <NUM> and <NUM>. In the present embodiment, the feeding points <NUM> and <NUM> are located nearer to the coupling portion <NUM> than to the open portion <NUM> in the first direction. The feeding points <NUM> and <NUM> are located so that they sandwich the slot <NUM> in the second direction. By supplying high-frequency power between the feeding points <NUM> and <NUM>, the multiband antenna <NUM> is operated as an antenna. For supplying the high-frequency power between the feeding points <NUM> and <NUM>, a coaxial cable (not shown) may be used, for example.

The multiband antenna <NUM> has a plurality of operating frequencies. In detail, the multiband antenna <NUM> has three operating frequencies depending on the conductive main portion <NUM>, the first radiation element <NUM> and the second radiation element <NUM>, respectively. An electrical length of each of the first radiation element <NUM> and the second radiation element <NUM> is equal to a quarter of a wavelength of the operating frequency corresponding thereto. The electrical length of the first radiation element <NUM> and the electrical length of the second radiation element <NUM> are different from each other. For example, the electrical length of the second radiation element <NUM> is longer than the electrical length of the first radiation element <NUM>. With this structure, the second radiation element <NUM> can have the operating frequency lower than that of the first radiation element <NUM>. The operating frequency depending on the conductive main portion <NUM> is lower than that of only the conductive main portion <NUM> because of influence of each of the first radiation element <NUM>, the second radiation element <NUM> and the grounding terminal <NUM>. Accordingly, when trying to obtain a specific operating frequency, each of the first radiation element <NUM>, the second radiation element <NUM> and the grounding terminal <NUM> helps to downsize the multiband antenna <NUM>. The additional element <NUM> adjusts the impedance of the multiband antenna <NUM> and lowers the operating frequencies of the multiband antenna <NUM> or helps to downsize the multiband antenna <NUM>.

Although the description about one embodiment of the present invention is made above, the multiband antenna <NUM> may be modified as follows. In each of modifications mentioned below, the same or the similar components same as or similar to those of the multiband antenna <NUM> are represented by the same or the similar reference signs and the description thereabout is omitted.

Referring to <FIG>, a multiband antenna <NUM>0A of a first modification is different from the multiband antenna <NUM> (see <FIG>) of the aforementioned embodiment in that positions of feeding points 211A and 213A are different from those of the feeding points <NUM> and <NUM> (see <FIG>).

As shown in <FIG>, the positions of the feeding points 211A and 213A are nearer to an open portion <NUM> than to a coupling portion <NUM> in the first direction. Thus, in the present invention, the positions of the feeding points <NUM> and <NUM> or 211A and 213A may be changed according to intended antenna properties.

Referring to <FIG>, a multiband antenna 10B of a second modification is different from the multiband antenna 10A (see <FIG>) of the first modification in that a shape of an additional element 40B is different from that of the additional element <NUM> (see <FIG>).

As shown in <FIG>, the additional element 40B has an L-shape when viewed along the third direction. A size of a front edge 401B of the additional element 40B is larger than that of the front edge <NUM> of the additional element <NUM> in the first direction. With this structure, a capacitance between the additional element 40B and a second slot edge portion <NUM> can be larger than that between the additional element <NUM> and the second slot edge portion <NUM>. A larger capacitance can achieve a lower operating frequency and downsize the multiband antenna 10B.

Referring to <FIG>, a multiband antenna 10C of a third modification is different from the multiband antenna <NUM> (see <FIG>) of the aforementioned embodiment in that it has a grounding terminal 60C which has a part extending in a direction intersecting with the specific plane or the X-Y plane.

As shown in <FIG>, in the present modification, the grounding terminal 60C has a rectangular flat plate-like shape, and the whole thereof extends downward from a front edge of a second slot edge portion <NUM>. However, the present invention is not limited thereto. The grounding terminal 60C may extend forward from the front edge of the second slot edge portion <NUM> and then extend the direction intersecting with the specific plane. In that case, the part extending in the direction intersecting with the specific plane may be on a plane perpendicular to the first direction or on a plane perpendicular to the second direction.

Referring to <FIG>, a multiband antenna 10D of a fourth modification is different from the multiband antenna 10C (see <FIG>) of the third modification in that a position of a grounding terminal 60D is different from that of the grounding terminal 60C (see <FIG>).

As shown in <FIG>, in the present modification, the grounding terminal 60D is positioned apart from both ends of a second slot edge portion <NUM> in the first direction. Moreover, the grounding terminal 60D is nearer to an open portion <NUM> than to a coupling portion <NUM> in the first direction. Thus, in the present invention, the position of the grounding terminal <NUM>, 60C or 60D may be changed according to intended antenna properties.

Referring to <FIG>, a multiband antenna 10E of a fifth modification is different from the multiband antenna 10C (see <FIG>) of the third modification in that it has an additional grounding terminal 60E in addition to a grounding terminal 60C.

As shown in <FIG>, in the present modification, the additional grounding terminal 60E extends downward from a front edge of an end portion <NUM> of a second slot edge portion <NUM>. The additional grounding terminal 60E helps to improve reliability of the multiband antenna 10E. Thus, the multiband antenna of the present invention can be provided with any number of grounding terminals.

Referring to <FIG>, a multiband antenna 10F of a sixth modification is different from the multiband antenna 10C (see <FIG>) of the third modification in that a shape of a second radiation element 50F is different from that of the second radiation element <NUM> (see <FIG>). In detail, in the multiband antenna 10F, the second radiation element 50F has an extension portion <NUM> in addition to a long portion <NUM> and a short portion <NUM>.

As shown in <FIG>, the extension portion <NUM> extends from a front-end portion of the short portion <NUM> in the second orientation. The extension portion <NUM> can lengthen an electrical length of the second radiation element 50F without increasing a size of the second radiation element 50F in the first direction. Thus, in the present invention, a shape of the second radiation element <NUM> or 50F may be changed according to intended antenna properties.

Referring to <FIG>, a multiband antenna <NUM> of a seventh modification is different from the multiband antenna 10F (see <FIG>) of the sixth modification in that a shape of a second radiation element <NUM> is different from that of the second radiation element 50F (see <FIG>). In detail, in the multiband antenna <NUM>, the second radiation element <NUM> has a vertical portion <NUM> in addition to the structure of the second radiation element 50F.

As shown in <FIG>, the vertical portion <NUM> extends downward from a rear edge of a long portion <NUM>. In the first direction, a size of the vertical portion <NUM> is smaller than that of the long portion <NUM>. The vertical portion <NUM> helps to improve strength and radiation properties of the second radiation element <NUM>. Thus, in the present invention, a shape of the second radiation element <NUM>, 50F or <NUM> may be changed according to intended antenna properties.

Referring to <FIG>, a multiband antenna <NUM> of an eighth modification is different from the multiband antenna <NUM> (see <FIG>) of the seventh modification in that it is provided with a third radiation element <NUM>.

As shown in <FIG>, the third radiation element <NUM> has an additional long portion <NUM>, an additional short portion <NUM> and an additional extension portion <NUM>. The third radiation element <NUM> is formed so that it is substantially same as a second radiation element <NUM>. The additional long portion <NUM> is coupled with a lower edge of a vertical portion <NUM>. When viewed along the third direction, the third radiation element <NUM> overlaps with the second radiation element <NUM>. Thus, in the multiband antenna of the present invention, the number of radiation elements or passive antennas, i.e., the number of operating frequencies or an operating frequency band can be freely set.

Referring to <FIG>, a multiband antenna <NUM> of a ninth modification is different from the multiband antenna 10C (see <FIG>) of the third modification in that it is provided with a fourth radiation element <NUM>.

As shown in <FIG>, the fourth radiation element <NUM> has a rectangular shape long in the first direction. The fourth radiation element <NUM> extends from an end portion <NUM> of a first slot edge portion <NUM> in the first orientation. In the first direction, a size of the fourth radiation element <NUM> is equal to or less than half of a size of a long portion <NUM> of a second radiation element <NUM>. However, the present invention is not limited thereto. The shape and the size of the fourth radiation element <NUM> may be freely set according to intended antenna properties.

Referring to <FIG>, a multiband antenna 10J of a tenth modification is different from the multiband antenna 10C (see <FIG>) of the third modification in that it is provided with a fifth radiation element <NUM>.

As shown in <FIG>, the fifth radiation element <NUM> has a rectangular shape long in the first direction. The fifth radiation element <NUM> extends from an end portion <NUM> of a second slot edge portion <NUM> in the first orientation. In the first direction, a size of the fifth radiation element <NUM> is equal to or less than half of a size of a long portion <NUM> of a second radiation element <NUM>. However, the present invention is not limited thereto. The shape and the size of the fifth radiation element <NUM> may be freely set according to intended antenna properties.

Referring to <FIG>, a multiband antenna <NUM> of an eleventh modification is different from the multiband antenna 10E (see <FIG>) of the fifth modification in that it is provided with a feeding terminal <NUM>.

As shown in <FIG>, the feeding terminal <NUM> has a part extending in a direction intersecting with the specific plane. In the present modification, the feeding terminal <NUM> has a rectangular flat plate-like shape, and the whole thereof extends downward from a front edge of a first slot edge portion <NUM>. However, the present invention is not limited thereto. The feeding terminal <NUM> may extend forward from the front edge of the first slot edge portion <NUM> and then extend the direction intersecting with the specific plane. In that case, the part extending in the direction intersecting with the specific plane may be on a plane perpendicular to the first direction or on a plane perpendicular to the second direction.

As understood from <FIG>, in the third direction, a size of the feeding terminal <NUM> is equal to that of a grounding terminal 60C and to that of an additional grounding terminal 60E. With this structure, the multiband antenna <NUM> can be surface mounted on an object (not shown), such as a circuit board. For example, if conductive patterns <NUM> corresponding to the feeding terminal <NUM>, the grounding terminal 60C and the additional grounding terminal 60E, respectively, are formed on the object, the feeding terminal <NUM>, the grounding terminal 60C and the additional grounding terminal 60E can be connected to the conductive patterns <NUM> corresponding to them, respectively.

Referring to <FIG>, a multiband antenna <NUM> of a twelfth modification is different from the multiband antenna <NUM> (see <FIG>) of the aforementioned embodiment in that it further has a first extension slot edge portion <NUM>.

As shown in <FIG>, the first extension slot edge portion <NUM> has an L-shape when viewed along the third direction. In detail, the first extension slot edge portion <NUM> extends from an end portion <NUM> of a first slot edge portion <NUM> in the first orientation and then extends forward. In the present modification, an open portion <NUM> is formed at a part of a conductive main portion <NUM> which is different from the first slot edge portion <NUM>. In detail, the open portion <NUM> is located between a front edge of a second slot edge portion <NUM> and a front edge of the first extension slot edge portion <NUM> and opened forward.

Referring to <FIG>, a multiband antenna <NUM> of a thirteenth modification is different from the multiband antenna <NUM> (see <FIG>) of the aforementioned embodiment in that it further has a first extension slot edge portion <NUM> and a second extension slot edge portion <NUM>.

As shown in <FIG>, the first extension slot edge portion <NUM> has a rectangular shape and extends from an end portion <NUM> of a first slot edge portion <NUM> in the first orientation. Moreover, the second extension slot edge portion <NUM> has an inverted L-shape when viewed along the third direction. In detail, the second extension slot edge portion <NUM> extends from an end portion <NUM> of a second slot edge portion <NUM> in the first orientation and then extends rearward. In the present modification, an open portion <NUM> is formed at a part of a conductive main portion <NUM> which is different from the first slot edge portion <NUM>. In detail, the open portion <NUM> is located between a rear edge of the first extension slot edge portion <NUM> and a rear edge of the second extension slot edge portion <NUM> and opened rearward.

Referring to <FIG>, a multiband antenna 10N of a fourteenth modification is different from the multiband antenna <NUM> (see <FIG>) of the aforementioned embodiment in that a shape of an additional element 40N is different from that of the additional element <NUM> (see <FIG>). However, the additional element 40N of the present modification has in common with the additional element <NUM> in that it extends toward a second specific area <NUM> through a first specific area <NUM>.

In detail, as shown in <FIG>, the additional element 40N of the present modification has a crank shape when viewed along the third direction. In more detail, the additional element 40N of the present modification extends forward from a lower end of a rear portion <NUM> of a first radiation element <NUM> and then extends in the first orientation and further extends forward. Additionally, each of the first specific area <NUM> and the second specific area <NUM> is an area on a plane which is perpendicular to the third direction and which is positioned apart from the specific plane in the third direction. In addition, the first specific area <NUM> is an area overlapping with a first slot edge portion <NUM> in the third direction. Moreover, the second specific area <NUM> is an area overlapping with a second slot edge portion <NUM> in the third direction. In the present modification, the additional element 40N is located on a plane where the first specific area <NUM> and the second specific area <NUM> are included, and a front edge 401N of the additional element 40N is in the second specific area <NUM>. The additional element 40N forms a capacitance between itself and the second slot edge portion <NUM> and adjusts an impedance of the multiband antenna 10N, so that it lowers operating frequencies of the multiband antenna 10N or helps to downsize the multiband antenna 10N.

Although the specific explanation about the present invention is made above with reference to concrete embodiments, the present invention is not limited thereto but susceptible of various modifications and alternative forms without departing from the scope of the invention defined by the claims. For example, the structures of the modifications <NUM> to <NUM> may be suitably selected and combined.

Claim 1:
A multiband antenna comprising a conductive main portion (<NUM>) forming a slot antenna, a radiation element (<NUM>) and an additional element (<NUM>), wherein:
the conductive main portion (<NUM>) comprises a first slot edge portion (<NUM>) and a second slot edge portion (<NUM>);
the conductive main portion (<NUM>) is formed with a slot (<NUM>) and an open portion (<NUM>);
the slot (<NUM>) has a longitudinal direction in a first direction;
each of the first slot edge portion (<NUM>) and the second slot edge portion (<NUM>) has a longitudinal direction in the first direction;
the first slot edge portion (<NUM>) and the second slot edge portion (<NUM>) are arranged so that the first slot edge portion (<NUM>) and the second slot edge portion (<NUM>) sandwich the slot (<NUM>) therebetween;
the open portion (<NUM>) is formed at a part of the conductive main portion (<NUM>) which is different from the first slot edge portion (<NUM>) and opens the slot (<NUM>) outside of the conductive main portion (<NUM>);
the radiation element (<NUM>) has a first part (<NUM>) and a second part (<NUM>);
the first part (<NUM>) extends from an end portion (<NUM>) of the first slot edge portion (<NUM>) in a second direction perpendicular to the first direction; and
the second part (<NUM>) extends from an end portion of the first part (<NUM>) in the first direction, characterized in that
the additional element (<NUM>) extends from the second part (<NUM>) to or toward a second specific area (<NUM>) through a first specific area (<NUM>) without being brought into contact with the conductive main portion (<NUM>);
the first specific area (<NUM>) is an area which overlaps with the first slot edge portion (<NUM>) in a third direction perpendicular to both the first direction and the second direction; and
the second specific area (<NUM>) is an area which overlaps with the second slot edge portion (<NUM>) in the third direction.