KR20080080066A - Multi-band antenna - Google Patents

Abstract

A multi-band antenna is provided to improve efficiency and gain thereof and to maintain broadband and multi-band characteristics by having a plurality of slots. A multi-band antenna includes a radiator(240). The radiator includes a main radiator(241), first and second sub radiators(242,243), and first and second slots(250,260). The main radiator has a rectangular shape. The first sub radiator is vertically connected to one side of the main radiator. The second sub radiator is vertically connected to the other side of the main radiator. The first slot has first to fifth slot segments. The first slot segment is formed along a boundary between the main radiator and the first sub radiator, and one end thereof is opened. One end of the second slot segment is vertically connected to the other end of the first slot segment. The third slot segment is vertically connected to the other end of the second slot segment and extended in opposite directions. The fourth slot segment is vertically extended from one end of the third slot segment. The fifth slot segment is vertically extended from the other end of the third slot segment. The second slot has sixth to ninth slot segments(261-264). One end of the sixth slot segment is opened to one side of the main radiator. One end of the seventh slot segment is connected to the other end of the sixth slot segment. One end of the eighth slot segment is connected to the other end of the seventh slot segment. The ninth slot segment is extended from the other end of the seventh slot segment to the second sub radiator and vertical to the eighth slot segment.

Description

Multiband Antenna {MULTI-BAND ANTENNA}

The present invention relates to a multiband antenna and a mobile communication terminal including the same. More particularly, the present invention relates to an antenna having a plurality of slots formed therein to exhibit multiband characteristics.

With the rapid development of mobile communication technology, wireless communication devices are becoming smaller and more versatile. With the focus on miniaturization of portable terminals, internal antennas have been introduced, and due to the diversification of portable services, the development of antennas that can satisfy various frequency bands currently serviced by a single antenna is in progress.

The built-in antenna has various problems because it is an antenna mounted inside the terminal. It is small and mounted inside the terminal, which reduces the gain of the antenna and close to the internal elements, thereby affecting the characteristics of the antenna due to the surrounding metallic materials. In addition, in the case of a mobile phone having various functions, the antenna characteristics may be changed by a camera, an LCD, a battery, etc., and therefore the gain of the antenna must be high and the frequency band must be wideband so that the characteristics cannot be changed even when affected by peripheral devices.

1 is a perspective view of a conventional planar inverted F-type antenna (PIFA).

Referring to FIG. 1, a radiator 101 is mounted on a ground plane 100, and a shorting plate 102 is formed to be bent perpendicularly to an end of the radiator 101 to be in contact with the ground plane 100. The feed point 103 is positioned for impedance matching of the antenna.

The planar inverted-F antenna is a type of short-circuit microstrip antenna, and is formed by forming a shorting plate 102 between the ground plane 100 and the radiator 101 where the electric field becomes zero. It is regarded as a microstrip antenna with the length of 101 reduced in half. At this time, if the width of the shorting plate 102 is made narrower than the width of the radiator 101, the effective inductance of the antenna element increases, and the resonant frequency is lower than the resonant frequency of the general short-circuit type microstrip antenna having the same length of radiator. . Therefore, it is possible to further reduce the length of the short-circuit microstrip antenna and to have the same structure as the PIFA.

Conventional inverted-F antenna has a dual band characteristics, the disadvantage is that the gain and the efficiency of the antenna is lowered because the form of the folded PIFA.

In order to solve the above problems, it is an object of the present invention to provide an antenna for mobile communication which can maintain the characteristics of wideband and multiband while increasing the gain and efficiency while keeping the size of the antenna small.

The present invention, the kitchen body of the rectangular shape; A first sub-radiation body that is bent and connected perpendicularly to one side of the kitchen body; And a second sub-radiation body that is bent and connected perpendicularly to the other side surface adjacent to one side of the kitchen body, the first slot segment being formed along a boundary between the kitchen body and the first sub-radiation body and having one end open. And a second slot segment having one end vertically connected to the other end of the first slot segment, a third slot segment extending in both directions opposite to the other end of the second slot segment, and one end of the third slot segment. A first slot including a fourth slot segment extending vertically from the second slot, a fifth slot segment extending vertically from the other end of the third slot segment extending up to the second sub-radiator, and one side of the kitchen body A sixth slot segment having an open end, a seventh slot segment having one end connected to the other end of the sixth slot segment, and the seventh slot three And an eighth slot segment having one end connected to the other end of the segment, and extending from the other end of the seventh slot segment to the second sub-radiator, the ninth slot segment perpendicular to the eighth slot segment. Provided is a multiband antenna having a second slot.

The first slot covers the GSM (880-960 MHz), GPS (1.575 GHz), DCS (1.71-1.88 GHz), and PCS (1.85-1.99 GHz) bands, and by the second slot The antenna may cover the ISM (2.4 GHz) band.

According to the present invention, an antenna and an antenna exhibiting multiband characteristics can be obtained by a plurality of slots.

Hereinafter, the present invention will be described in detail with reference to the drawings.

2 is an exploded perspective view of a substrate and a radiator included in a mobile communication terminal according to a preferred embodiment of the present invention.

Referring to FIG. 2, the mobile communication terminal 200 according to the present embodiment includes a dielectric substrate 210 and a radiator 240.

The dielectric substrate 210 may be formed of a material having a predetermined dielectric constant, and a material such as ceramic or FR-4 may be used.

A ground plane 220 is formed in one region of the dielectric substrate 210. The ground plane 220 serves as a shield when other passive elements and active elements (not shown) required for the mobile communication terminal are mounted on the substrate.

The radiator 240 is mounted on the other area of the substrate on which the ground plane 220 is not formed.

The radiator 240 is mounted to be spaced apart from the substrate 210 by a predetermined interval.

The first slot 250 and the second slot 260 are formed on the radiator 240 to indicate the characteristics of the multi-band.

The power supply line 270 and the ground line 280 having one end connected to the radiator 240 are formed on the substrate 210.

The feed line 270 has one end 271 provided as a contact area with the radiator 240 and the other end is opened to be connected to an external feed unit.

One end 281 of the ground line 280 is provided as a contact area with the radiator 240, and the other end is in contact with the ground surface 220.

The feed line 270 and the ground line 280 are printed in the form of a micro strip on the substrate 210, and at this time, it is preferably designed to match the resistance of 50 kW.

One ends 271 and 281 of each of the feed line 270 and the ground line 280 are provided as a contact area with the radiator 240. In this embodiment, since the radiator is mounted so as not to be in direct contact with the substrate, it is preferable that the ends 271 and 281 of the power supply line and the ground line are formed to have a predetermined height.

The feed line 270 and the ground line 280 are formed to be spaced apart by a predetermined interval.

By adjusting the distance between the feed line 270 and the ground line 280, it is possible to adjust the frequency characteristics. In this embodiment, the frequency characteristics of the GSM (880 MHz to 960 MHz) band can be adjusted by adjusting the interval between the feed line 270 and the ground line 280.

In the region in which the ground plane 220 is not formed in the substrate 210, a matching ground plane 230 is formed to overlap a portion of the radiator to form a capacitive coupling with the radiator 240. The matching ground plane 230 extends from the ground plane 220.

The matching ground surface 230 is not in direct contact with the radiator 240, but serves to adjust the impedance by the radiator by capacitive coupling. The strength of the capacitive coupling may be adjusted by the spacing between the matching ground plane 230 and the radiator 240 or the adjacent area. Therefore, the broadband characteristics of the antenna can be obtained by adjusting the size of the matching ground plane 230.

The matching ground plane 230 may be formed to overlap a portion of the radiator 240, and may be formed of the same material as the ground plane 220.

3 is an exploded view of the radiator used in the preferred embodiment of FIG.

Referring to FIG. 3, the radiator 240 used in the present embodiment includes a kitchen body 241, a first sub-radiator 242, and a second sub-radiator 243.

In the present embodiment, the kitchen body 241 is a rectangular shape, the first sub-radiator 242 is vertically connected to one side of the main radiator, the second sub-radiator 243 is the main radiator 241 Connected vertically to the other side of the

As described above, the end of the radiator is bent vertically, so that the antenna can be miniaturized.

The radiator is formed with a first slot 250 and a second slot 260.

By the first slot 250 and the second slot 260, the kitchen body 241 may be divided into three regions 241a, 241b, and 241c to represent frequency characteristics of a multi-band.

The first slot 250 is formed along a boundary between the kitchen body 241 and the first sub-radiator 242 and has a first slot segment 251 open at one end and the first slot segment 251. A second slot segment 252 having one end perpendicularly connected to the other end of the second slot segment 252, a third slot segment 253 extending in opposite directions opposite to the other end of the second slot segment 252, and the third slot segment 253 ) May include a fourth slot segment 254 extending vertically at one end and a fifth slot segment 255 extending vertically at the other end of the third slot segment 253.

The third slot segment 253 may be divided into two regions 253a and 253b, and one region 253a may extend to the second sub-radiator 243.

In this embodiment, the current in the radiator is caused by a slot consisting of the first slot segment 251, the second slot segment 252, the third slot segment 253a and the fifth slot segment 255 of the first slot. The path is formed to obtain a characteristic satisfying the GSM frequency band.

In addition, another current path is formed in the radiator by a slot formed of the third slot segment 253 and the fourth slot segment 254 of the first slot, thereby obtaining a characteristic satisfying the GPS, DCS, and PCS frequency bands. have.

The second slot 260 may include a sixth slot segment 261 having one end open to one side of the kitchen body 241 and a seventh slot having one end connected to the other end of the sixth slot segment 261. A segment 262, an eighth slot segment 263 having one end connected to the other end of the seventh slot segment 262, and extending from the other end of the seventh slot segment 262 to the second sub-radiator 243. And a ninth slot segment 264 perpendicular to the eighth slot segment 263. The first slot segment 261 of the second slot 260 is preferably formed to have a wider width than other slot segments.

In the present embodiment, another current path is formed in the radiator by the second slots 260 formed by the segments 261, 262, 263, 264, thereby obtaining a characteristic satisfying the ISM frequency band.

The lengths of the first slot and the second slot may be variously implemented, and the resonance characteristics of the antenna may be changed according to the change in the length of the slot. If the length of the slot is changed, the current path formed inside the radiator is changed by the slot.

4 is a rear view of the substrate and the radiator included in the mobile communication terminal according to another embodiment of the present invention.

Referring to Fig. 4, the mobile communication terminal of this embodiment includes a dielectric substrate 410, a radiator 440, a matching ground plane 430, and fixing means 491 and 492.

The fixing means 491 and 492 support the radiator 440 to be spaced apart from the substrate 410. As the fixing means 491 and 492, a dielectric other than a conductor may be used, and plastic or ceramic may be used.

The radiator 440 is spaced apart from the matching ground plane 430 formed on the substrate 410 by the fixing means 491 and 492. According to the separation distance, the degree of capacitive coupling is changed, it is possible to adjust the characteristics of the antenna by adjusting the height of the fixing means (491, 492).

To increase the distance H between the radiator 440 and the matching ground plane 430, the height of the fixing means 491 and 492 may be increased or the width of the sub-radiator of the radiator may be narrowed. However, the radiator 440 should be in contact with at least the terminals 471 and 481 of the feed line and the ground line formed on the substrate, respectively. Since the height of the terminals 471 and 481 of the feed line and the ground line is high in manufacturing process, the radiator 440 corresponds to the terminals 471 and 472 of the feed line and the ground line. The region may be formed to be drawn out.

5 is a graph showing return loss according to frequency in a mobile communication terminal according to a preferred embodiment of the present invention.

In the following examples, a substrate and a radiator used in the mobile communication terminal according to the preferred embodiment of the present invention described in FIG. 2 were used, wherein a FR having a size of 40 mm x 90 mm x 0.4 mm and a dielectric constant of 4.5 was used. A -4 substrate was used, and the size of the radiator (main radiator) was 36 mm x 20 mm.

Referring to Fig. 5, frequencies of 878 MHz to 970 MHz, 1.47 GHz to 2.0 GHz, and 2.2 GHz to 2.5 GHz are satisfied at -6 GHz or less (VSWR = 3: 1). Accordingly, the mobile communication terminal satisfies all GSM (880 to 960 MHz), GPS (1.575 GHz), DCS (1.71 to 1.88 GHz), PCS (1.85 to 1.99 GHz), and ISM (2.4 GHz) frequency bands. can see.

6 is a reflection loss graph in which a GSM frequency band is adjusted by adjusting a distance between a power supply line and a ground line in the mobile communication terminal of the above-described preferred embodiment.

Referring to FIG. 6, when the distance between the power supply line and the ground line is 5 mm, the resonance frequency of the GSM (880 to 960 MHz) band is located in a low frequency band (left side in the drawing), but when the interval is 9 mm, resonance is performed. The frequency is located in the high frequency band (right in the drawing). When the interval is set to 11 mm, a resonant frequency is formed in the intermediate frequency region in the case of 5 mm and 9 mm.

Therefore, the resonance frequency in the GSM (880 ~ 960MHz) band can be adjusted by adjusting the distance between the feed line and the ground line.

Fig. 7 shows frequency characteristics when the size of the matching ground plane is adjusted in the mobile communication terminal of the preferred embodiment. In this embodiment, the length of the mating ground plane is made constant and the width is changed.

Referring to FIG. 7, it can be seen that the bandwidth is wider when the width of the matching ground plane is 14 mm compared with the case where the width is 10 mm. However, when the width of the mating ground plane is 18 mm, the bandwidth is narrowed again.

Therefore, broadband characteristics can be obtained by adjusting the matching ground plane.

8A and 8B show gain and radiation efficiency of an antenna in a mobile communication terminal according to the preferred embodiment.

Referring to FIGS. 8A and 8B, in the present embodiment, a gain of 1.83 [dBi] and an efficiency of 0.95 can be obtained in the GSM (880 to 960 MHz) band, and 3.13 in the GPS (1.575 GHz) band. gain of 0.9 dB, efficiency of 0.98, gain of 3.7 dBi and gain of 0.99 in the DCS (1.71 to 1.88 GHz), gain of 4.03 dBi and efficiency of 0.99 in the PCS 1.85 to 1.99 GHz, In the ISM (2.4GHz) band, a gain of 3.59 [dBi] and an efficiency of 0.98 can be obtained, respectively.

As such, the present invention is not limited by the above-described embodiment and the accompanying drawings. That is, the shape of the slot formed in the radiator, the area of the matching ground plane, the distance between the substrate and the radiator may be implemented in various ways. It is intended that the scope of the invention be defined by the appended claims, and that various forms of substitution, modification, and alteration are possible without departing from the spirit of the invention as set forth in the claims. Will be self-explanatory.

1 is a perspective view of a planar inverted-F antenna according to the prior art.

2 is an exploded perspective view of the substrate and the radiator included in the mobile communication terminal according to the preferred embodiment of the present invention.

3 is an exploded view of a radiator included in a mobile communication terminal according to a preferred embodiment of the present invention.

4 is a rear view of the substrate and the radiator included in the mobile communication terminal according to another embodiment of the present invention.

5 is a graph showing return loss according to frequency in the mobile communication terminal according to the preferred embodiment of the present invention.

6 is a reflection loss graph in which a GSM frequency band is adjusted by adjusting a distance between a power supply line and a ground line in the mobile communication terminal according to the above-described preferred embodiment.

Fig. 7 shows a change in frequency characteristics in accordance with a change in the size of the matching ground plane in the mobile communication terminal of the above preferred embodiment.

8A and 8B show the gain and the radiation efficiency of the antenna in the mobile communication terminal according to the preferred embodiment.

<Code Description of Main Parts of Drawing>

241: kitchen body 242: first sub-radiation body

243: second sub-radiator 250: first slot

260: second slot

Claims (2)

Rectangular kitchen utensils; A first sub-radiation body that is bent and connected perpendicularly to one side of the kitchen body; And a second sub-radiation body that is bent and connected vertically to the other side surface adjacent to one side of the kitchen body, A second slot segment formed along a boundary between the kitchen body and the first sub-radiator, the first slot segment having one end opened, a second slot segment vertically connected to the other end of the first slot segment, and the second slot A third slot segment vertically connected to the other end of the segment and extending in opposite directions, a fourth slot segment vertically extending from one end of the third slot segment, and the third slot extending to the second subradiator A first slot comprising a fifth slot segment extending vertically at the other end of the segment; And A sixth slot segment having one end opened to one side of the kitchen body, a seventh slot segment having one end connected to the other end of the sixth slot segment, and an eighth having one end connected to the other end of the seventh slot segment And a second slot including a slot segment and a ninth slot segment extending from the other end of the seventh slot segment to the second sub-radiator and perpendicular to the eighth slot segment. The method of claim 1, The first slot indicates the frequency characteristics of the GSM (880 to 960 MHz), GPS (1.575 GHz), DCS (1.71 to 1.88 GHz), and PCS (1.85 to 1.99 GHz) bands; And wherein said antenna exhibits a frequency characteristic of an ISM (2.4 GHz) band by said second slot.

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