Planar inverted F antenna

Provided is a planar inverted F antenna including a ground surface having a finite plane and formed of a conductive material, an antenna body at a certain distance from the ground surface and transmitting and receiving radio waves, a feed line for electrically connecting the ground surface and the antenna body, a ground pin for grounding the antenna body to the ground surface, and at least one auxiliary plate disposed between the antenna body and the ground surface. Therefore, it is possible to readily overcome design restrictions of the antenna in keeping with the slimming and miniaturization of mobile communication terminals by installing the auxiliary plate between the ground surface and the antenna body.

The present application makes reference to and claims all benefits accruing under 35 U.S.C. §119 from an application for PLANER INVERTED F ANTENNA earlier filed in the Korean Intellectual Property Office on 16 Jul. 2007, and there duly assigned Serial No. 2007-71318.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a planar inverted F antenna, and more particularly, to a planar inverted F antenna capable of improving antenna performance by adding an auxiliary plate between a ground surface and an antenna body.

BACKGROUND OF THE INVENTION

For mobile communication terminal antennas, various models for performing the following properties have been proposed. In order to accomplish high efficiency, low loss, compact and lightweight structure, omni-directionality of radiation pattern, impedance matching for increasing radiation efficiency, packaging technology for design simplification, low cost, human body protection technology from radiation, wide bandwidth, low power consumption, improved technology appropriate to electromagnetic environment, etc., various kinds of antenna technologies have been developed.

Along with the slimming and miniaturization of mobile communication terminals, the size of the antenna has also decreased. At this point, technology capable of minimizing the size of the antenna while still maintaining the same function is one of the most important technologies.

Such antennas may be classified as either internal or external antennas depending on the installation position. External antennas include monopole antennas, whip antennas, helical antennas, sleeve antennas, N-type antennas, chip antennas, FS-FIFI antennas, etc., all of which are installed at the exterior of terminals.

Internal antennas include inverted F antennas, planar inverted F antennas, diversity antennas, micro-strip antennas, twisted loop antennas, EID antennas, etc., all of which are installed in the interior of terminals.

Planar antennas may be classified further as inverted F antennas, planar inverted F antennas, diversity antennas, micro-strip antennas, EID antennas, FS-FIFA antennas, RCDLA antennas, or DTSA antennas, all of which have a planar structure.

In the conventional planar antennas, since the size of the antenna has also decreased with the slimming and miniaturization of mobile communication terminals, it is difficult to minimize the size of the antenna while still maintaining the same function.

SUMMARY OF THE INVENTION

To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide a planar inverted F antenna capable of reducing the size of the antenna and readily tuning the antenna in keeping with the slimming and miniaturization of mobile communication terminals by installing an auxiliary plate between a ground surface and an antenna body.

According to an exemplary embodiment of the present invention, a planar inverted F antenna includes: a ground surface having a finite plane and formed of a conductive material; an antenna body at a certain distance from the ground surface and transmitting and receiving radio waves; a feed line for electrically connecting the ground surface and the antenna body; a ground pin for grounding the antenna body to the ground surface; and at least one auxiliary plate disposed between the antenna body and the ground surface.

According to another exemplary embodiment of the present invention, a planar inverted F antenna includes: a ground surface having a finite plane and formed of a conductive material; an antenna body at a certain distance from the ground surface and transmitting and receiving radio waves; a feed line for electrically connecting the ground surface and the antenna body; a ground pin for grounding the antenna body to the ground surface; and at least one auxiliary plate disposed between the antenna body and the at least one auxiliary plate to be inclined with respect to the ground surface.

According to still another exemplary embodiment of the present invention, a planar inverted F antenna includes: a ground surface having a finite plane and formed of a conductive material; an antenna body at a certain distance from the ground surface and transmitting and receiving radio waves; a feed line for electrically connecting the ground surface and the antenna body; a ground pin for grounding the antenna body to the ground surface; and at least one auxiliary plate disposed between the antenna body and the ground surface, a portion of which is covered by the antenna body, and the other portion of which is exposed.

Here, the auxiliary plate may have a width relatively smaller than, equal to, or relatively larger than that of the antenna body. The auxiliary plate may have a “┐” or “T” shape.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a perspective view of a planar inverted F antenna in accordance with a first exemplary embodiment of the present invention,FIG. 2is a side view ofFIG. 1,FIG. 3is a top view ofFIG. 1, andFIG. 4is a graph showing the performance of the planar inverted F antenna in accordance with the first exemplary embodiment of the present invention.

Referring toFIGS. 1 to 3, a planar inverted F antenna100in accordance with a first exemplary embodiment of the present invention includes a ground surface110having a finite plane and formed of a conductive material.

Here, conventionally, the ground surface110is a printed circuit board. An antenna body120is horizontally installed over the ground surface110at a certain distance from the ground surface110and transmits/receives radio waves.

A feed line130is vertically installed on the ground surface110to electrically connect the antenna body120to the ground surface110.

A ground pin140is formed at an end of the antenna body120to ground the antenna body120to the ground surface110.

An auxiliary plate150is installed between the antenna body120and the ground surface110.

A single auxiliary plate150may be installed, two auxiliary plates150may be installed as shown inFIG. 5, or, while not shown, three or more auxiliary plates may be installed.

The auxiliary plate150may have a width w relatively smaller than that of the antenna body120.

Hereinafter, operation of the planar inverted F antenna in accordance with a first exemplary embodiment of the present invention will be described.

Because the size of the antenna also is reduced in keeping with the slimming and miniaturization of mobile communication terminals and frequency is inversely proportional to the length of the antenna, design of the antenna is subjected to many restrictions.

The planar inverted F antenna100in accordance with the first exemplary embodiment of the present invention can remarkably reduce the total size of the antenna at the same frequency by installing the auxiliary plate150between the ground surface110and the antenna body120in consideration of the above problems.

Therefore, in keeping with the slimming and miniaturization of mobile communication terminals, it is possible to design a smaller antenna.

FIG. 4is a graph for comparing the performance of a conventional planar inverted F antenna with the performance of the planar inverted F antenna in accordance with the first exemplary embodiment of the present invention.

In the graph ofFIG. 4, the X-axis represents frequency, and the Y-axis represents standing wave ratio. A solid line represents an experiment value of the present invention, and a broken line represents an experiment value of the conventional art.

As a result of measuring frequencies of arbitrary points around a standing wave ratio of −15 dB to −12 dB, the frequencies of the conventional art are 1.9322 GHz and 1.9839 GHz, respectively, and the frequencies of the present invention are 1.4945 GHz and 1.5100 GHz, respectively.

Comparing the present invention with the conventional art in this graph, it will be appreciated that the frequency of the present invention is reduced by about 0.4 to 0.5 GHz. Considering the inverse relationship between frequency and antenna size, it will be appreciated that the total size of the antenna can be remarkably reduced when the same frequency is used.

FIG. 6is a perspective view of another modified example of the auxiliary plate of the planar inverted F antenna in accordance with the first exemplary embodiment of the present invention,FIG. 7is a perspective view of still another modified example of the auxiliary plate of the planar inverted F antenna in accordance with the first exemplary embodiment of the present invention, andFIG. 8is a side view of yet another modified example of the auxiliary plate of the planar inverted F antenna in accordance with the first exemplary embodiment of the present invention.

First, as shown inFIG. 6, in the planar inverted F antenna100in accordance with the first exemplary embodiment of the present invention, the auxiliary plate150may have the same width w as the antenna body120.

In addition, as shown inFIG. 7, in the planar inverted F antenna100in accordance with the first exemplary embodiment of the present invention, the auxiliary plate150may have a width w larger than that of the antenna body120.

As shown inFIGS. 6 and 7, when the widths w of the auxiliary plate150and the antenna body120have various ratios, it is possible to more readily perform a tuning process depending on design conditions of the mobile communication terminals.

In addition, as shown inFIG. 8, an auxiliary plate150′ may have a “T” shape.

Further, as shown inFIG. 2, the feed line130may be located at a position corresponding to ⅓ of the antenna body120, or as shown inFIG. 9, the feed line130may be located at a position corresponding to ½ of the antenna body120.

Meanwhile,FIG. 10is a perspective view of a planar inverted F antenna in accordance with a second exemplary embodiment of the present invention,FIG. 11is a side view ofFIG. 10, andFIG. 12is a plan view ofFIG. 10.

Referring toFIGS. 10 to 12, a planar inverted F antenna200in accordance with the second exemplary embodiment of the present invention includes a ground surface210having a finite plane and formed of a conductive material.

Here, conventionally, the ground surface210is a printed circuit board. An antenna body220is horizontally installed over the ground surface210at a certain distance from the ground surface210and transmits/receives radio waves.

A feed line230is installed on the ground surface210in an inclined manner to electrically connect the antenna body220to the ground surface210.

A ground pin240is formed at an end of the antenna body220to ground the antenna body220to the ground surface210.

An auxiliary plate250is installed between the antenna body220and the ground surface210in an inclined manner.

The auxiliary plate250may have a width w relatively smaller than that of the antenna body220.

Hereinafter, operation of the planar inverted F antenna in accordance with the second exemplary embodiment of the present invention will be described.

The planar inverted F antenna200in accordance with the second exemplary embodiment of the present invention can remarkably reduce the total size of the antenna at the same frequency by installing the inclined auxiliary plate250between the ground surface210and the antenna body220, in consideration of the above problems.

Therefore, in keeping with the slimming and miniaturization of mobile communication terminals, it is possible to design a smaller antenna.

FIG. 13is a graph for comparing the performance of a conventional planar inverted F antenna with the performance of the planar inverted F antenna in accordance with the second exemplary embodiment of the present invention.

In the graph ofFIG. 13, the X-axis represents frequency, and the Y-axis represents standing wave ratio. A solid line represents an experiment value of the present invention, and a broken line represents an experiment value of the conventional art.

As a result of measuring frequencies of arbitrary points around a standing wave ratio of −15 dB to −12 dB, the frequencies of the conventional art are 1.9322 GHz and 1.9839 GHz, respectively, and the frequencies of the present invention are 1.3945 GHz and 1.4100 GHz, respectively.

Comparing the present invention with the conventional art in this graph, it will be appreciated that the frequency of the present invention is reduced by about 0.5 to 0.6 GHz.

Considering the inverse relationship between frequency and antenna size, it will be appreciated that the total size of the antenna can be remarkably reduced when the same frequency is used, and the second exemplary embodiment has a better effect than that of the first exemplary embodiment.

FIG. 14is a perspective view of a modified example of an auxiliary plate of the planar inverted F antenna in accordance with the second exemplary embodiment of the present invention,FIG. 15is a perspective view of another modified example of the auxiliary plate of the planar inverted F antenna in accordance with the second exemplary embodiment of the present invention, andFIG. 16is a perspective view of a modified example of a feed line of the planar inverted F antenna in accordance with the second exemplary embodiment of the present invention.

First, as shown inFIG. 14, in the planar inverted F antenna200in accordance with the second exemplary embodiment of the present invention, the auxiliary plate250may have the same width w as the antenna body220.

In addition, as shown inFIG. 15, in the planar inverted F antenna200in accordance with the second exemplary embodiment of the present invention, the auxiliary plate250may have a width w larger than that of the antenna body220.

Further, as shown inFIG. 12, the feed line230may be located at a position corresponding to ⅓ of the antenna body220, or as shown inFIG. 16, the feed line230may be located at a position corresponding to ½ of the antenna body220.

FIG. 17is a perspective view of a planar inverted F antenna in accordance with a third exemplary embodiment of the present invention,FIG. 18is a top view ofFIG. 17, andFIG. 19is a side view ofFIG. 17.

Referring toFIGS. 17 to 19, a planar inverted F antenna300in accordance with the third exemplary embodiment of the present invention includes a ground surface310having a finite plane and formed of a conductive material.

Here, conventionally, the ground surface310is a printed circuit board. An antenna body320is horizontally installed over the ground surface310at a certain distance from the ground surface310and transmits/receives radio waves.

A feed line330is vertically installed on the ground surface310to electrically connect the antenna body320to the ground surface310.

A ground pin340is formed at an end of the antenna body320to ground the antenna body320to the ground surface310.

An auxiliary plate350is installed between the antenna body320and the ground surface310.

A portion of the auxiliary plate350is covered by the antenna body320, and the other portion of the auxiliary plate350is exposed.

The auxiliary plate350may have a width w relatively smaller than that of the antenna body320.

Hereinafter, operation of the planar inverted F antenna in accordance with the third exemplary embodiment of the present invention will be described.

The planar inverted F antenna300in accordance with the third exemplary embodiment of the present invention can remarkably reduce the total size of the antenna at the same frequency by installing the auxiliary plate350between the ground surface310and the antenna body320in consideration of the above problems.

Therefore, in keeping with the slimming and miniaturization of mobile communication terminals, it is possible to design a smaller antenna.

FIG. 20is a graph for comparing the performance of a conventional planar inverted F antenna with the performance of the planar inverted F antenna in accordance with a third exemplary embodiment of the present invention.

In the graph ofFIG. 20, the X-axis represents frequency, and the Y-axis represents standing wave ratio. A solid line represents an experiment value of the present invention, and a broken line represents an experiment value of the conventional art.

As a result of measuring frequencies of arbitrary points around a standing wave ratio of −15 dB to −12 dB, the frequencies of the conventional art are 1.9322 GHz and 1.9839 GHz, respectively, and the frequencies of the present invention are 1.2945 GHz and 1.3100 GHz, respectively.

Comparing the present invention with the conventional art in this graph, it will be appreciated that the frequency of the present invention is reduced by about 0.6 to 0.7 GHz.

Considering the inverse relationship between frequency and antenna size, it will be appreciated that the total size of the antenna can be remarkably reduced when the same frequency is used, and the third exemplary embodiment has a better effect than that of the first exemplary embodiment.

As can be seen from the foregoing, a planar inverted F antenna in accordance with the present invention can reduce the size of the antenna and readily tune the antenna in keeping with the slimming and miniaturization of mobile communication terminals by installing an auxiliary plate between a ground surface and an antenna body.

Accordingly, in keeping with the slimming and miniaturization of the mobile communication terminals, it is possible to remarkably reduce the size of the antenna at the same frequency.