KR100688074B1 - Omnidirectional Circular Polarization Folded Microstrip Antenna - Google Patents

Abstract

In order to be able to miniaturize and obtain an omnidirectional circular polarization, the patch is formed in a folded shape in a substantially "c" shape along the diagonal direction so that the triangular plates are located at a predetermined interval from each other, and the patch "approximately" Between the shape of the plate and the flat plate which is installed at a predetermined distance so as not to short-circuit between the patch and the serrated corners of the vertical surface where the upper and lower surfaces of the patch are connected. An omni-directional circularly polarized folded microstrip antenna comprising a dielectric layer and a feed line connected to an arbitrary point of a patch for feeding power is provided.

Microstrip, Antenna, Board, Patch, Ground Plate, Circularly Polarized, Axial Ratio, Omni-Directional, Small, Folded

Description

Omnidirectional Circular Polarization Folded Microstrip Antenna

1 is a perspective view showing a conventional folded microstrip antenna.

FIG. 2 is a graph showing a measurement of a radiation pattern when the top surface is fed in a conventional folded microstrip antenna.

3 is a graph showing a measurement of the radiation pattern when the lower surface power supply in the conventional folded microstrip antenna.

4 is a perspective view showing an embodiment of an omnidirectional circularly polarized folded microstrip antenna according to the present invention.

5 is an exploded perspective view showing an embodiment of an omnidirectional circularly polarized folded microstrip antenna according to the present invention.

Figure 6 is a cross-sectional view showing one ground plate in one embodiment of the omni-directional circularly polarized folded microstrip antenna according to the present invention.

Figure 7 is a cross-sectional view showing both ground planes in one embodiment of the omni-directional circularly polarized folded microstrip antenna according to the present invention.

8 is a bottom view showing a state in which a feed line is formed by a coplanar method in an embodiment of the omnidirectional circularly polarized folded microstrip antenna according to the present invention.

9 is a perspective view showing another embodiment of the omni-directional circularly polarized folded microstrip antenna according to the present invention.

Figure 10 is a perspective view showing the structure of the ground plate in another embodiment of the omni-directional circular polarized folded microstrip antenna according to the present invention.

11 is a plan view showing an unfolded state of the patch in another embodiment of the omnidirectional circularly polarized folded microstrip antenna according to the present invention.

12 is a graph illustrating a return loss measured when a ground plate having one ground plane is used in another embodiment of the omnidirectional circularly polarized folded microstrip antenna according to the present invention.

FIG. 13 is a graph illustrating an axial ratio measured when a ground plate having one ground plane is used in another embodiment of the omnidirectional circularly polarized folded microstrip antenna according to the present invention.

FIG. 14 is a graph illustrating return loss when a ground plate having both ground planes is used in another embodiment of the omnidirectional circularly polarized folded microstrip antenna according to the present invention.

FIG. 15 is a graph illustrating an axial ratio when a ground plate having both ground planes is used in another embodiment of the omnidirectional circularly polarized folded microstrip antenna according to the present invention.

16 is a perspective view showing still another embodiment of the omni-directional circularly polarized folded microstrip antenna according to the present invention.

17 is a side view showing still another embodiment of an omnidirectional circularly polarized folded microstrip antenna according to the present invention.

The present invention relates to an omnidirectional circularly polarized folded microstrip antenna, and more particularly, omnidirectional circular polarization can be obtained by folding a square patch diagonally so as to surround the ground plate with a triangle on the upper and lower surfaces. Relates to a possible omni-directional circularly polarized folded microstrip antenna.

Recently, interest in wireless communication using satellites such as GPS and satellite DMB is increasing as an additional service of personal portable wireless communication service PCS and PDA.

However, in the case of satellite communication (center frequency 1.575GHz), the overall size of the system is getting smaller due to the development of circuit technology, while the antenna has a great difficulty in miniaturization because its size is determined by the wavelength.

In addition, since the position of the satellite is shifted with time and the position and attitude of the receiver are changed, it greatly affects the transmission and reception of the satellite. Therefore, the antenna used in the satellite communication is required to have a small size and an omnidirectional characteristic. do.

On the other hand, the microstrip antenna is known to be suitable for satellite communication, aerospace and mobile communication systems because it is lightweight, flat structure, easy to compact and lightweight.

Conventional microstrip antennas have a dielectric layer formed to a predetermined thickness therebetween, and one side (top) is provided with a planar patch serving as an antenna, and the other side (bottom) is provided with a ground plate. The feeding of the feed is performed by feeding a power supply by installing a microstrip line or by feeding a probe (probe).

Korean Unexamined Patent Publication No. 2003-76039 proposes a folded microstrip patch antenna that is formed by folding a patch with a ground plate interposed therebetween so as to reduce the size of the same frequency. The folded microstrip patch antenna is a structure in which a general half-wavelength microstrip patch antenna is folded in half, and the electric field directions are all in the same phase in the same phase, and the magnetic flux density is combined not only in the radiation slot but also in the non-radiation slot. It is possible to reduce the size to 1/2, and the radial opening of the shape combined in phase can be seen as a single point charge source, thus making it omnidirectional.

After producing a folded microstrip patch antenna with the structure shown in FIG. 1, the radiation pattern measured by the upper surface feeding is shown in FIG. 2, and the radiation pattern measured by the lower surface feeding is shown in FIG.

In other words, as shown in FIG. 1, a 72 mm wide patch plate 4 is folded in a "c" shape with a folded microstrip patch antenna having a thickness of 0.8 mm and a ground plate 2 having a width of 80 mm x 40 mm. And a dielectric 6 having a thickness of 3 mm is provided between the ground plate 2 and the upper and lower surfaces of the patch plate 4. The ground plate 2 is provided so that the feed line 8 connected to one point of the patch plate 4 is not short-circuited with the ground plate 2.

As can be seen from FIG. 2 and FIG. 3, in the case of the top feeding, the gain of the E-plane radiation pattern is relatively low around 90 to 210 °, so that the overall omnidirectional characteristics are not obtained. In this case, since the E-plane radiation pattern exhibits an omni-direction characteristic similar to that of the overall gain better than that of the upper surface feeding, it can be confirmed that the feeding method is more effective for the omnidirectional characteristic.

The conventional folded microstrip patch antenna is a structure for obtaining linear polarization, and new research and development are required to obtain a circular polarization required for satellite communication.

The present invention has been made in view of the above points, and by minimizing by arranging the patch patch diagonally and the triangular patch surface exists above and below the ground plate between them, and the feed point is arranged to obtain a circular polarization. SUMMARY OF THE INVENTION An object of the present invention is to provide an omnidirectional circularly polarized folded microstrip antenna capable of obtaining omnidirectional circular polarization.

The omni-directional circularly polarized folded microstrip antenna proposed by the present invention is a patch having a rectangular plate folded in a substantially "c" shape along a diagonal direction so that triangles are positioned at predetermined intervals from each other, and the patch approximately A planar ground plate installed at predetermined intervals so as not to short-circuit the patch between the "c" shapes, a dielectric layer positioned between the ground plate and the patch, and a feed line connected to an arbitrary point of the patch for feeding power. It is made to include.

In the above, it is preferable to form the edge of the ground plate in contact with the vertical surface to which the upper and lower surfaces of the patch are connected in the form of a sawtooth because separation of the polarization is more effective.

It is preferable to connect the feed line to any point on the upper or lower surface of the patch, and if possible, to set the connection point to a position above or near the center line of the patch to improve symmetry.

Next, a preferred embodiment of the omnidirectional circularly polarized folded microstrip antenna according to the present invention will be described in detail with reference to the accompanying drawings.

First, an embodiment of the omni-directional circularly polarized folded microstrip antenna according to the present invention, as shown in Figures 4 to 6, the square plate is approximately "c along the diagonal direction so that the triangle is located at a predetermined interval from each other. A patch 10 having a shape folded into a shape, and a flat plate ground plate 20 which is installed at a predetermined interval so as not to be short-circuited with the patch 10 between the "c" shapes of the patch 10 and And a dielectric layer 30 positioned between the ground plate 20 and the patch 10, and a feed line 40 connected to an arbitrary point of the patch 10 to supply power.

The patch 10 is formed in two layers folded in half about a diagonal line so as to form an approximately "C" shape when viewed from the side.

When the triangles of the upper and lower surfaces of the patch 10 formed of two layers are formed as isosceles triangles or equilateral triangles, the circular polarization characteristics of the double resonance do not appear, and thus the trapezoid triangles (patches disposed on the plane of the ground plate 20) It is preferable to form in (10) two sides of a triangle having a different length) or a right triangle.

The patch 10 is configured to fold a substantially rectangular plate in a diagonal direction so that the upper and lower surfaces are formed in a substantially right triangle.

The patch 10 may be formed using a copper (Cu) thin plate, or may be a metal thin plate such as silver (Ag) or aluminum (Al) having excellent electrical conductivity and good formability and workability. .

The dielectric layer 30 may be a dielectric of various materials such as Teflon, ceramic, glass, epoxy, styrofoam, or the like, and may be formed as an air layer by installing a spacer member.

As shown in FIG. 6, the ground plate 20 is formed by coating a dielectric substrate 22 made of a dielectric such as epoxy, styrofoam, ceramic, or the like and a conductive material on at least one surface of the dielectric substrate 22. It consists of a ground plane 24.

As the conductive material for forming the ground plane 24, a material having excellent electrical conductivity such as copper (Cu) or aluminum (Al) is used, and the dielectric substrate 22 is applied by screen printing or deposition. do.

The ground plane 24 may be formed by bringing a thin plate of a material having excellent electrical conductivity into close contact with the dielectric substrate 22.

As shown in FIGS. 4 and 5, a feed line 40 is provided on the dielectric substrate 22 in an insulated state so as not to be short-circuited with a conductive material forming the ground plane 24. The feed is connected to the feed point 18, which is a point of the patch 10.

As shown in FIG. 7, the ground plane 24 may be formed by applying a conductive material to both surfaces of the dielectric substrate 22 to correspond to the upper and lower patches 10, respectively.

When the ground plane 24 is formed on both sides of the dielectric substrate 22 in the ground plate 20 as described above, the asymmetric structure of the axial ratio is improved as compared with the ground plane 24 formed on only one side.

When the ground plane 24 is formed by applying a conductive material to both surfaces of the dielectric substrate 22, it is preferable to form the feed line 40 by a coplanar feeding method (see FIG. 8).

That is, as shown in FIG. 8, a part of one ground plane 24 is removed, and the feed line 42 is formed at predetermined intervals from the ground plane 24, and the feed line 40 is comprised.

In the above, the electric power feeding by the feed line 40 can be performed to the upper surface side of the patch 10, and can also be performed to the lower surface side of the patch 10. As shown in FIG. However, as is already known, since the lower surface feeding side is superior in the omnidirectional characteristic than the upper surface feeding, the lower surface feeding method is more effective for omnidirectional characteristics.

And another embodiment of the omni-directional circular polarized folded microstrip antenna according to the present invention, as shown in Figures 9 to 11, the ground plate 20 in contact with the vertical surface is connected to the upper and lower surfaces of the patch 10 A sawtooth-shaped separation portion 25 is formed at the edge of the.

As described above, when the separation part 25 is formed in the corner of the ground plane 24 of the ground plate 20 in a sawtooth shape, the electric fields inside the patch 10 are separated at right angles to each other to separate two polarized waves perpendicular to each other. Is more effective.

The ground plane 24 may be formed on only one side of the patch 10 so as to correspond to only one of the top and bottom surfaces thereof, or may be formed on both sides so as to correspond to both the top and bottom surfaces of the patch 10. .

Even when the ground plane 24 is formed on both sides in the above, the separation portions 25 are formed on the corners that meet the vertical plane of the patch 10 on both sides.

Also in the above-described other embodiments, the present invention can be implemented in the same configuration as the above-described embodiment except for the above-described configuration, and thus detailed description thereof will be omitted.

12 to 15 show graphs for measuring the return loss and the axial ratio in another embodiment of the omnidirectional circularly polarized folded microstrip antenna according to the present invention. In FIG. 12, the reflection loss when the ground plane 24 is formed on one side is measured and shown. In FIG. 13, the axial ratio when the ground plane 24 is formed on one side is measured and shown. In FIG. The reflection loss when (24) is formed on both surfaces is measured and shown, and in FIG. 15, the axial ratio when the ground plane 24 is formed on both surfaces is measured and shown.

The antenna for measuring the return loss and the axial ratio is a rectangular patch 10 having a length of 83 mm x 86.5 mm in length (A) and length (B) and a length of 120 mm x in length (G) and length (F). It is formed by folding the ground plate 20, which is 60 mm, into a substantially "c" shape.

In the above, the ground plate 20 forms a sawtooth separation portion 25 in which a triangular shape having a height E of 5 mm is successively formed at the corners facing the vertical surface of the patch 10.

The dielectric substrate 22 constituting the ground plate 20 uses an epoxy substrate having a thickness of 0.8 mm, and a dielectric constant between the ground plate 20 and the upper and lower surfaces of the patch 10 is a dielectric layer 30. A styrofoam (dielectric constant = 1.06) of similar thickness 2.4 mm is inserted.

In the case where the thickness of the dielectric layer 30 is set to 3 mm, the double resonance characteristic can be obtained at the position where the feed point 18 is about 10 mm from the center to the left side in FIG. 11.

However, symmetry is required for omnidirectional radiation pattern characteristics, so it is desirable that the feed point 18 be as close to the center as possible.

As a result of examining the position of the feed point 18 while adjusting the thickness of the dielectric layer 30 determining the gap between the patch 10 and the ground plate 20, the feed point becomes smaller as the thickness of the dielectric layer 30 becomes smaller. It was confirmed that the position of 18 is moved toward the center of the patch 10. However, when the thickness of the dielectric layer 30 is too small, the gap between the patch 10 and the ground plate 20 becomes too close, which causes difficulty in impedance matching.

Therefore, the thickness of the dielectric layer 30 is set to 2.4 mm to satisfy both impedance matching and symmetry, and the position of the feed point 18 is set to 6 mm from the center to measure the return loss and the axial ratio. It was.

And the distance (D) from the edge of the end surface of the ground plate 20 of the feed point 18 is set to 17mm to form a feed line 40 and connect with the feed point 18. The feed point 18 is formed on the lower surface of the patch 10.

As shown in FIG. 12, the return loss in the case of using the ground plate 20 having one ground plane 24 is -25.6 dB at 1.575 GHz and -10 dB bandwidth is 110 MHz. .

Moreover, as shown in FIG. 13, the axial ratio in the case of using the ground plate 20 which has one ground plane 24 is confirmed at 5.96 dB in the -X axis direction, 2.53 dB in the Z axis direction, and 1.10 in the -Z axis direction. It became.

Then, in order to reduce the influence of the connector while using the ground plate 20 having both ground planes 24, the lengths of the width A and length B of the patch 10 are set to 88 mm x 92 mm, and the ground plate ( The lengths of the horizontal (G) and the vertical (F) of 20) were set to 120 mm x 75 mm, and the feed point 18 was positioned at the center of the patch 10, and then the reflection loss and the axial ratio were measured.

In the above case, as shown in FIG. 14, the return loss in the case of using the ground plate 20 having both ground planes 24 is -21.3 dB at the center frequency of 1.575 GHz, and the -10 dB bandwidth is 99 MHz. It can be confirmed that the characteristics are obtained.

As shown in Fig. 15, the axial ratio in the case of using the ground plate 20 having both ground planes 24 is confirmed at 2.78 dB in the -X axis direction, 3.91 dB in the Z axis direction and 2.02 in the -Z axis direction. It became.

When comparing FIG. 13 and FIG. 15 from the above, it can be seen that the axial ratio in the -X axis direction is 5.96 dB in FIG. 13, but improved to 3.18 dB in FIG. 15. In FIG. 13, all of them showed good characteristics, while in FIG. 15, the axial ratio in the -Z axis direction was increased to 3.91 dB. Overall, the axial ratio of FIG. 15 is better than that of FIG.

Since the characteristics of the resonant frequency change as the shape and size of the ground plate 20 changes from the above measurement results, the size of the patch 10 must be changed for impedance matching, and the patch 10 and the ground plate ( It can be seen that a circular polarization having a double resonance characteristic and a good axial ratio can be obtained by appropriately setting the size of 20), the installation of one or both sides of the ground plane 24, the position of the feed point 18, and the like. have.

And another embodiment of the omni-directional circular polarized folded microstrip antenna according to the present invention, as shown in Figs. 16 and 17, the patch 10 at a predetermined interval so as not to short-circuit with the patch 10 It further includes an auxiliary patch 50 is formed to be reduced in proportion to be installed to surround the patch 10 from the outside.

A dielectric layer 32 made of a dielectric is formed between the auxiliary patch 50 and the patch 10.

The dielectric layer 32 may be made of an air layer, or may be made of various dielectric materials.

Since the feed line 40 is not connected to the auxiliary patch 50, it is maintained in a non-powered state.

When the auxiliary patch 50 is provided as described above, the band is widened by the patch 10 (wide band).

In the above, the auxiliary patch 50 is preferable to set the reduction ratio in the range of approximately 50 to 95% of the patch 10 because the effective broadband can be obtained.

Also in the above-described other embodiments, the present invention can be implemented in the same configurations as the above-described embodiments and other embodiments except for the above-described configuration, and thus detailed descriptions thereof will be omitted.

In the above, a preferred embodiment of the omni-directional circularly polarized folded microstrip antenna according to the present invention has been described. However, 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 do this and this also belongs to the scope of the present invention.

According to the omnidirectional circularly polarized folded microstrip antenna according to the present invention as described above, since the patch is folded, omnidirectional characteristics can be obtained, and the size of the plane can be reduced, thereby miniaturizing.

In addition, according to the omnidirectional circular polarized folded microstrip antenna according to the present invention, since the position of the feed point is set asymmetrically and the edge of the ground plate is formed in the sawtooth shape, it is possible to obtain a circular polarization having a double resonance characteristic.

Claims (8)

A patch having a rectangular plate folded in a "c" shape along a diagonal direction such that a right triangle or an isosceles triangle is positioned at predetermined intervals from each other, A flat plate ground plate installed at predetermined intervals so as not to be shorted with the patch between the "c" shapes of the patch; A dielectric layer located between the ground plate and the patch; An omnidirectional circularly polarized folded microstrip antenna comprising a feedline connected to a point of the patch for feeding power. The method according to claim 1, The omni-directional circular polarized folded microstrip antenna forming a sawtooth-shaped edge of the ground plate in contact with the vertical surface is connected to the upper and lower surfaces of the patch. The method according to claim 1 or 2, The omni-directional circular polarized folded microstrip antenna setting a feed point connected to the feed line at a position above or near the center line of the patch. The method according to claim 3, The feed point is an omni-directional circular polarized folded microstrip antenna formed on the upper or lower surface of the patch. The method according to claim 1 or 2, The ground plane is a omnidirectional circular polarized folded microstrip antenna formed by forming a ground plane with a conductive material on one or both surfaces of a dielectric substrate made of a dielectric. The method according to claim 5, The feed line is a omni-directional circular polarized folded microstrip antenna formed on the ground plate by the coplanar feeding method. The method according to claim 1 or 2, An omnidirectional circular polarized folded microstrip antenna further comprising an auxiliary patch formed at a reduced ratio from the patch at a predetermined interval so as not to short-circuit with the patch for widening. The method according to claim 7, The auxiliary patch omni-directional circularly polarized folded microstrip antenna is not connected to the feed line.

Images