KR20050043178A - Miniaturized microstrip patch antenna with slit structure - Google Patents

Abstract

A ground plate formed in a predetermined shape, a patch provided at a predetermined distance from the ground plate, and a patch for cutting one or more edges into a predetermined shape to form one or more slits so as to be miniaturized at the same resonance frequency, and a ground plate The present invention provides a small microstrip patch antenna having a slit structure including a dielectric layer disposed between and a patch.

The slit is formed by cutting a part of the corner of the patch into various shapes such as square, triangular, light bulb, "T", star, and cross shape, and in the patch, the edge is folded in a step shape toward the ground plate to form a bent portion. do.

Description

Miniaturized Microstrip Patch Antenna with Slit Structure}

The present invention relates to a small microstrip patch antenna having a slit structure, and more particularly, to a small microstrip patch antenna having a slit structure that can be miniaturized by forming slits of various shapes.

With the recent development of wireless communication technology, the generalization and popularization of information communication terminals such as mobile phones, PDAs, GPS systems, and the like, have been made. Small and light antennas are essential for these information communication terminals, and microstrip patch antennas, which can be manufactured in a thin shape and can be manufactured in a flat form, are mainly used.

The conventional microstrip patch antenna has a dielectric layer formed to have a predetermined thickness therebetween, and a planar patch serving as an antenna is installed on one side (upper side), and a ground plate is installed on the opposite side (lower side). Is done.

In general, the size of the microstrip patch antenna is proportional to the wavelength of the design frequency. In order to reduce the size of the same frequency, the microstrip patch antenna should be made of a dielectric material having a high dielectric constant. However, when a dielectric having a high dielectric constant is used, there is a limit because the radiation characteristic of the antenna is degraded and the gain is reduced as a result. In addition, when the dielectric constant of the dielectric material is increased, the dielectric loss is increased, the manufacturing cost is relatively increased, and the production yield is drastically reduced. Therefore, there is a limit in shortening the antenna size by using a dielectric having a high dielectric constant. .

In order to reduce the size of the microstrip patch antenna, the present inventors measured the characteristics of each antenna while variously modifying the shape of the patch, and in the case of forming a square slit on the non-radiated slot of the patch, the resonance frequency in the patch of the same area. It was found that the lowering, the research on this has led to the present invention.

SUMMARY OF THE INVENTION The present invention has been made in view of this point, and an object thereof is to provide a small microstrip patch antenna having a slit structure that can be miniaturized by lowering the resonance frequency by forming slits and / or stepped bends.

The small microstrip patch antenna having a slit structure proposed by the present invention is provided with a ground plate formed in a predetermined shape and a predetermined distance from the ground plate, and at least one edge is cut into a predetermined shape to cut one or more slits. It comprises a patch to be formed, and a dielectric layer provided between the ground plate and the patch.

The slit is formed by cutting a part of the edge of the patch into various shapes such as square, triangular, light bulb, "T" shape, star shape and cross shape.

The slit is formed at the edge on the non-radiative slot of the patch.

The patch can also be folded toward the ground plane in a stepped corner or the entire corner on the radial slot.

Next, a preferred embodiment of a small microstrip patch antenna having a slit structure according to the present invention will be described in detail with reference to the drawings.

First, a first embodiment of a small microstrip patch antenna having a slit structure according to the present invention, as shown in Figures 1 to 3, the ground plate 10 formed in a predetermined shape, the ground plate 10 and A patch 20 provided at a predetermined interval and cutting one or more edges into a predetermined shape to form one or more slits 22, and a dielectric layer 30 provided between the ground plate 10 and the patch 20. )

A feed line 42 connected to a feed member 40 installed on the ground plate 10 is connected to the patch 20.

The ground plate 10 has a feed hole 14 through which the feed line 42 penetrates so that the feed line 42 is connected to the feed member 40 without being electrically shorted with the ground plate 10. do.

The power feeding member 40 is provided with an insulating member (not shown) between the ground plate 10 and the ground plate 10 so as not to be electrically shorted.

The feed member 40 and the feed line 42 are made of conductive lines that are printed and formed in the actual microstrip patch antenna. Since the power feeding member 40 and the power feeding line 42 can be implemented in the same configuration as a general microstrip patch antenna, detailed description thereof will be omitted.

The patch 20 and the ground plate 10 are formed using a metal thin plate having excellent electrical conductivity. For example, the patch 20 and the ground plate 10 may be made of a metal thin plate such as copper (Cu) or aluminum (Al), and have excellent electrical conductivity, silver (Ag) having good moldability and workability, It is also possible to use a metal thin plate such as gold (Au).

An air layer may be used as the dielectric constituting the dielectric layer 30, and dielectrics of various materials such as Teflon, ceramic, glass, epoxy, and synthetic resin may be applied.

In the case where the air layer is used as the dielectric layer 30, the gap maintaining member 32 is installed on the ground plate 10 to maintain the gap between the patch 20 and the ground plate 10 and to support the patch 20. .

The spacing member 32 is preferably installed in a predetermined pattern in the corner portion and / or the center portion of the patch 20 so as not to affect the dielectric constant while stably supporting the patch 20. In addition, the spacing member 32 is preferably a non-metallic material or a non-conductive material having a low dielectric constant such as synthetic resin or wood so as not to affect the dielectric constant of the dielectric layer 30.

The slit 22 is formed by cutting a portion of the corner on the non-radiated slot of the patch 20 in a "T" shape. That is, in order to obtain linear polarization, the slits 22 are formed symmetrically on both sides of the non-radiative slots of the patch 20.

In the second embodiment of the small microstrip patch antenna having the slit structure according to the present invention, the slits 22 are formed to form symmetrical shapes with the sides facing each other on four corners.

As described above, when the slits 22 are formed in four corners so as to form symmetrical shapes with each other, the horizontal and vertical lengths of the patch 20 can be reduced, thereby further miniaturization.

In the case of the configuration as described above, it is also possible to implement circular polarization by configuring the horizontal and vertical lengths of the patch 20 differently or feeding them with a phase difference.

Although the shape of the patch 20 has been described above in the shape of a rectangle, the present invention is not limited thereto and may be formed in various shapes such as circles, triangles, and pentagons.

Next, the effect of the slit 22 on the resonance frequency of the antenna will be described.

First, as shown in FIG. 5, a patch 4 having a rectangular shape of 90 mm × 84 mm is installed at a center of the grounding plate 2 having a rectangular shape of 300 mm × 300 mm, with a distance of 3 mm, and the 90 mm of the patch 4 as shown in FIG. 5. A microstrip patch antenna was fabricated using a general planar patch (4) with feed points formed so that both edges were radiation slots and 84 mm edges were non-radiation slots. 7 is shown.

As can be seen from Fig. 6, the return loss was measured at -28.3dB and -10dB bandwidth at 41MHz (2.6%). As can be seen from Fig. 7, the gain was 7.7dBd and the -3dB beam width was 67.7 ° in the H-plane. , E-plane 69.1 °.

As shown in FIG. 8, a patch 20 having a rectangular shape of 90 mm × 84 mm is provided at a center portion of the ground plate 10 having a rectangular shape of 300 mm × 300 mm at a distance of 3 mm, and the non-radiative slot of the patch 20 is provided. The width W and the depth D are set differently at both edges of 82 mm to form a square slit 22, and then the resonance frequency is measured. The result is shown in FIG.

In the above, the depth D of the slit 22 is set to 20 mm and 30 mm, respectively, and the width W of the slit 22 is differently set to 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, and 60 mm for each depth D. Set.

As shown in FIG. 9, the resonant frequency decreases as the width W of the slit 22 increases, while the width W of the slit 22 is about 40 mm, which is 50% of the resonant length of the patch 20. Saturated at the boundary showed a tendency to increase slightly. In the case where the depth D of the slit 22 is 30 mm, the resonance frequency tends to fall vertically by about 300 MHz. From these, it can be seen that the depth D acts more on the change of the resonance frequency than the width W of the slit 22.

In addition, as shown in FIG. 10 to confirm the change of the resonance frequency due to the influence of the depth D itself of the slit 22 which acts more on the change of the resonance frequency as described above, the width of the radiation slot is 90 mm. The return loss and the radiation pattern of the antenna to which the patch 8, which has a 40mm × 84mm slit-less square shape reduced to 40mm (44.4% reduction), are measured, and are shown in FIGS. 11 and 12.

When only the width of the patch 8 was reduced as described above, as shown in FIG. 11, the resonance frequency was shown at 1.575 GHz as shown in FIG. 6 to which the general patch 4 was applied. Therefore, the effect of lowering the resonance frequency caused by the slit 22 on the non-radiated slot should consider both the width W and the depth D of the slit 22, and only reducing the width or length of the patch 20 is resonance. It can be seen that there is no effect on the decrease in frequency. In the case of -10dB bandwidth, the frequency was reduced by 12MHz to 29MHz (1.84%) compared with 41MHz (2.6%) of FIG. 6 measured by applying the general patch (4). 8) This is a result of the relative decrease of the path of current distribution on the bottom.

In addition, as shown in FIG. 12, the gain of the patch 8 of FIG. 9 was reduced by 1.0 dB to 6.7 dBd compared to the 7.7 dBd of FIG. 7 to which the general patch 4 was applied. The plane was reduced by 62 ° to 5.7 ° compared to FIG. 7 with the general patch 4, and the H-plane increased by 14.9 ° compared with FIG. 7 with the general patch 4 at 84 °. It was confirmed that the resonance mode of the patch antenna was maintained.

As shown in FIG. 13, the length (resonance length) of the non-radiation slot is reduced from 84 mm to 50 mm (40.5% reduction), and the slit 22 having a width (W) of 30 mm and a depth (D) of 24 mm is placed in the non-radiation slot. A first embodiment of a small microstrip patch antenna having a slit structure according to the present invention using a patch 20 formed one by one in the center is fabricated, and the reflection loss and the radiation pattern are measured and shown in FIGS. 14 and 15.

As can be seen from Fig. 14, the -10 dB bandwidth was reduced by 13 MHz (2%) to 28 MHz compared to the 41 MHz of Fig. 6 to which the general patch 4 was applied. It is due to shrinking. As can be seen from FIG. 15, the gain is 6.1 dBd, which is 1.6 dB lower than the 7.7 dBd of FIG. 7 to which the general patch 2 is applied. In the case of the -3 dB beamwidth, the E-plane is 66.3 °, and the general patch (4 ), And the H-plane was 86.4 ° compared to FIG. 7 with 1), increased by 17.3 ° compared to Figure 7 with the general patch (4).

The slit 22 may be formed in a rectangular shape as shown in FIG. 13, may be formed in a "T" shape as shown in FIG. 2, and may be formed in a triangle shape as shown in FIG. 16. In addition, as shown in FIG. 17, it can also be formed in a bulb shape.

In addition, although the shape of the said slit 22 is not shown in figure, it can also be formed in various shapes, such as an inverted triangle shape, a rhombus shape, a star shape, and a cross shape.

In order to know the change of the resonance frequency and the reflection loss according to the shape of the slit 22, the same number of slits 22 (e.g., three at one corner) at the same position may have the same maximum depth D. The resonance frequency and the return loss were measured using the formed patch 20, and the results are shown in Table 1 below.

division Resonance Frequency (GHz) -10 dB bandwidth (MHz) Triangle Slit (Figure 16) 1.345 21.4 Rectangular Slit (Figure 13) 1.28 15.0 Bulb Slit (Figure 17) 1.26 15.6 "T" shaped slit (Figure 2) 1.20 12.6

As can be seen from Table 1 above, the decrease in the resonance frequency was greatest when the slit 22 was formed in a "T" shape, and the resonance frequency was lowered for all the slits 22 having various shapes. This is a phenomenon that occurs because the path of the current at the edge portion on the non-radiation slot having a relatively large current distribution is relatively longer than when the slot 22 is absent.

In the first embodiment of the small microstrip patch antenna having the slit structure according to the present invention, the size of the patch 20 and the "T" shaped slot 22 are formed as shown in FIG. It measures and shows in FIG.19 and FIG.20.

18, the length of the patch 20 was reduced by 42.9% from 84 mm to 48 mm at the same center frequency (1.575 GHz).

As can be seen from FIGS. 19 and 20, compared with FIGS. 6 and 7, a decrease in the -10 dB bandwidth due to the size reduction of the patch 20 is shown, and a wide angle of -3 dB beamwidth is shown in the E-plane. A decrease in gain is seen.

In the second embodiment of the small microstrip patch antenna having the slit structure according to the present invention, the size of the patch 20 and the "T" shaped slot 22 are formed as shown in FIG. It shows in 22. For comparison, the return loss of the antenna to which the 86.5 mm x 82 mm planar patch 4 is applied is measured and shown in FIG.

As can be seen from FIG. 22 and FIG. 24, a center frequency of 1.575 GHz was obtained with an area reduction effect of 54.2%.

In the third embodiment of the small microstrip patch antenna having the slit structure according to the present invention, as shown in FIGS. 25 and 26, the edges of both sides of the radial slot on which the slit 22 of the patch 20 is not formed are stepped. It is folded toward the ground plate 10 in the shape to form the bent portion 24.

In addition, according to the fourth embodiment of the small microstrip patch antenna having the slit structure according to the present invention, as shown in Fig. 27, the entire edge of the patch 20 is folded in a stepped shape toward the ground plate 10, and the curved portion is bent. To form (24).

In the above, the corner portions where the neighboring horizontal portions of the bent portion 24 meet are cut out so as not to be connected to each other.

In order to obtain linear polarization, the slit 22 may be formed only at both corners of the non-radiative slot (not shown), and in order to obtain circular polarization, the slit 22 is formed at all corners ( 27).

The slit 22 is easy to form in the horizontal portion of the bent portion 24, but the formation of the slit 22 is formed by extending to the upper surface of the patch 20 through the bent portion 24 as shown in FIG. It is also possible.

Next, in order to confirm the characteristic change of the antenna according to the formation of the bent portion 24, as shown in FIG. 29, the patch 20 is formed to measure the return loss, and the result is shown in FIG. In the case of FIG. 29, the resonance length of the patch 20 was shortened to 45 mm, and the -10 dB bandwidth was measured at 85 MHz (5.4%) at the center frequency of 1.575 MHz.

As shown in FIG. 31, the patch 20 is provided to obtain circular polarization, and the reflection loss and the radiation pattern are measured and shown in FIGS. 32 and 33. FIG. In the case of FIG. 31, the flatness of the patch 20 was greatly reduced to 54.2 mm x 61.5 mm. As shown in FIG. 32, the return loss was -10.5 dB at the center frequency of 1.575 GHz. As shown in FIG. The -3dB beamwidth was enlarged. This is because the area of the patch 20 is reduced, and in a GPS system or the like, since the -3dB beamwidth is important relative to the gain, this is not a problem.

Since the patch 20 can be reduced even when only the bent portion 24 is formed as described above, the patch (similar to the third and fourth embodiments of the small microstrip patch antenna having the slit structure according to the present invention) In the case where the slit 22 and the bent portion 24 are formed together, it can be seen that the reduction effect of the patch 20 is further increased.

In the sixth embodiment of the small microstrip patch antenna having the slit structure according to the present invention, as shown in Fig. 34, the slit 22 is formed in succession two or more stages.

As described above, in the case where the slit 22 is formed in multiple stages by successive two or more stages, as shown in FIG. 35, the resonant frequency appears at various points and can be used in multiple bands.

Although not described above, in the small microstrip patch antenna having the slit structure according to the present invention, the shapes of the various slits 22 may be combined. For example, it is also possible to form the triangular slit 22 and the "T" shaped slit 22 together.

In the above, a preferred embodiment of a small microstrip patch antenna having a slit structure according to the present invention has been described, but the present invention is not limited thereto, and various modifications are made within the scope of the claims and the detailed description of the invention and the accompanying drawings. It is possible to implement, and this also belongs to the scope of the present invention.

According to the small microstrip patch antenna having the slit structure formed as described above, in the case of having the same center frequency (resonant frequency) by forming the slits and / or stepped bends, the area of the patch is reduced by 40% or more. Since it is possible to miniaturize and lighten, it is very easy to apply to information communication devices such as mobile phones, PDAs and GPS.

In addition, the -3dB beamwidth, which is more important in the GPS system, is more important than the gain reduction caused by the reduction of the patch area.

1 is an exploded perspective view showing a first embodiment of a small microstrip patch antenna having a slit structure according to the present invention.

2 is a plan view showing a first embodiment of a small microstrip patch antenna having a slit structure according to the present invention.

3 is a cross-sectional view showing a first embodiment of a small microstrip patch antenna having a slit structure according to the present invention.

4 is a plan view showing a second embodiment of a small microstrip patch antenna having a slit structure according to the present invention.

5 is a view showing a microstrip patch antenna to which a 90 mm x 84 mm flat patch is applied, (a) is a plan view, and (b) is a sectional view.

FIG. 6 is a graph illustrating return loss measured using the microstrip patch antenna of FIG. 5.

FIG. 7 is a graph illustrating a radiation pattern measured by using the microstrip patch antenna of FIG. 5.

8 is a plan view for explaining a state in which the width (W) and the depth (D) of the rectangular slit in the small microstrip patch antenna having the slit structure according to the present invention.

FIG. 9 is a graph showing a change in resonant frequency according to changing the width W and the depth D of the rectangular slit in the small microstrip patch antenna having the slit structure according to the present invention of FIG. 8.

10 is a plan view showing a microstrip patch antenna to which a 40 mm x 84 mm flat patch is applied.

FIG. 11 is a graph illustrating return loss measured using the microstrip patch antenna of FIG. 10.

FIG. 12 is a graph illustrating a radiation pattern measured by using the microstrip patch antenna of FIG. 10.

Fig. 13 is a plan view showing a small microstrip patch antenna having a slit structure according to the present invention in which a rectangular slit having a width W of 30 mm x depth D of 24 mm is formed.

14 is a graph showing the return loss measured using a small microstrip patch antenna having a slit structure according to the present invention of FIG.

FIG. 15 is a graph illustrating a radiation pattern measured using a small microstrip patch antenna having a slit structure according to the present invention of FIG. 13.

16 is a plan view of a patch showing a state in which a triangular slit is formed in a small microstrip patch antenna having a slit structure according to the present invention.

17 is a plan view of a patch showing a state in which a bulbous slit is formed in a small microstrip patch antenna having a slit structure according to the present invention.

FIG. 18 is a view for explaining a state in which a standard of a "T" type slit is set in the first embodiment of a small microstrip patch antenna having a slit structure according to the present invention, (a) is a plan view, and (b) Is a cross section.

FIG. 19 is a graph showing the return loss measured using the first embodiment of the small microstrip patch antenna having the slit structure according to the present invention shown in FIG.

20 is a graph showing a radiation pattern measured using a first embodiment of a small microstrip patch antenna having a slit structure according to the present invention shown in FIG.

FIG. 21 is a view for explaining a state in which a standard of a "T" type slit is set in the second embodiment of the small microstrip patch antenna having the slit structure according to the present invention, (a) is a plan view, and (b) Is a cross section.

FIG. 22 is a graph showing the return loss measured using the second embodiment of the small microstrip patch antenna having the slit structure according to the present invention shown in FIG.

Fig. 23 shows a microstrip patch antenna to which a plane patch of 82 mm x 86.5 mm is applied, (a) is a plan view, and (b) is a sectional view.

24 is a graph showing the return loss measured using the microstrip patch antenna of FIG.

25 is a perspective view showing a third embodiment of a small microstrip patch antenna having a slit structure according to the present invention.

Fig. 26 is a sectional view showing a third embodiment of a small microstrip patch antenna having a slit structure according to the present invention.

27 is a perspective view showing a fourth embodiment of a small microstrip patch antenna having a slit structure according to the present invention.

28 is a perspective view showing a fifth embodiment of a small microstrip patch antenna having a slit structure according to the present invention.

Fig. 29 is a view showing a microstrip patch antenna to which both edges are folded in steps to form a bent portion, where (a) is a plan view and (b) is a sectional view.

30 is a graph showing the return loss measured using the microstrip patch antenna of FIG.

Fig. 31 is a view showing a microstrip patch antenna to which a patch is formed in which a bend is formed by folding the corners into a step shape, wherein (a) is a plan view and (b) is a sectional view.

FIG. 32 is a graph illustrating return loss measured using the microstrip patch antenna of FIG. 31.

FIG. 33 is a graph illustrating a radiation pattern measured using the microstrip patch antenna of FIG. 31.

34 is a perspective view showing a sixth embodiment of a small microstrip patch antenna having a slit structure according to the present invention.

35 is a graph showing the return loss measured using the sixth embodiment of the small microstrip patch antenna having the slit structure according to the present invention.

Claims (4)

A ground plate formed in a predetermined shape, A patch installed at a predetermined distance from the ground plate and cutting at least one edge portion into a predetermined shape to form at least one slit; A small microstrip patch antenna having a slit structure including a dielectric layer disposed between the ground plate and the patch. The method according to claim 1, The slit is a small microstrip patch antenna having a slit structure that is formed alone or in combination by selecting one or more of a quadrangular, triangular, bulb, "T" shape, inverted triangle shape, rhombus shape, cross shape, and star shape. . The method according to claim 1 or 2, A miniature microstrip patch antenna having a slit structure in which at least one edge of the patch is folded in a step shape toward the ground plate to form stepped bends. The method according to claim 1 or 2, Small microstrip patch antenna having a slit structure to form the slit successively in two or more stages.