KR100392231B1 - Microstrip Antenna Structure - Google Patents

Abstract

The present invention relates to a base station antenna for microstrip PCS and IMT-2000 services, and more particularly, to satisfy a frequency band required for PCS and IMT-2000 services, and to extend a single antenna to an array antenna. The present invention relates to a planar microstrip antenna structure having improved reflection loss characteristics due to coupling.

According to the present invention, the gap between the coupling slots is improved to reduce the reflection loss characteristic caused by the coupling between radiating elements, thereby improving the reflection loss characteristic at a low frequency, so that the voltage standing wave ratio is 1.3 or less (reflection loss -17 dB). The bandwidth is 600MHz (1.7GHz to 2.3GHz), which can be used for both PCS and IMT-2000 services, and it can be used to reduce the overlapping investments such as manufacturing and installation costs, and to beautify the environment due to the difficulty of antennas in urban areas. This is a useful invention that has the advantage of solving the problem.

Description

Broadband Microstrip Antenna Structure {Microstrip Antenna Structure}

The present invention relates to a base station antenna for microstrip PCS and IMT-2000 services, and more particularly, to satisfy a frequency band required for PCS and IMT-2000 services, and to extend a single antenna to an array antenna. The present invention relates to a planar wideband microstrip antenna structure having improved reflection loss characteristics due to coupling occurring.

Recently, with the rapid development of wireless communication technology, it is possible to provide various services to various fields such as cellular mobile communication, PCS, satellite mobile communication, and the like, and the future of IMT-2000 service, a next generation mobile communication system, is expected. Accordingly, researches on wireless access method, power control and interference controller, terminal, and network system technology for miniaturization and weight reduction of terminal and base station communication equipment, etc. have been actively conducted. Development of a multifunctional antenna that can integrate the provided services and new services into one antenna is emerging as an essential element.

The installation of new repeaters / base stations in accommodating new services is one of the serious problems in terms of the loss of costs and the destruction of environmental beautification due to the instability of antennas in dense areas.

Fig. 1 shows the configuration of a 1 × 4 array antenna in which a single antenna is designed as a form of a flat antenna used in the related art, and Fig. 2 is a sectional view showing an XY cross section of the structure shown in Fig. 1.

1 and 2, the conventional array antenna structure includes a third dielectric substrate 21, a parasitic element 12, a third foam material 22, a radiating element 11, a second dielectric substrate 23, The second foam material 24, the ground plane 14 including the coupling slot 13, the first dielectric substrate 25, the feed line 15, the first foam material 26, the conductor plate 16 They are stacked one by one. Since the bandwidth of the designed antenna has a broadband characteristic from 1.7 GHz to 2.3 GHz under voltage standing wave ratio of 1.3, the electrical length is different between radiating elements at low frequency because the electrical length is different even though the physical length between single elements is the same when extending to array antenna. The length becomes shorter.

Therefore, when the antenna is extended to the array antenna, the problem of a large deterioration in the return loss characteristics occurs.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an antenna structure using a multi-layered aperture coupling method having parasitic elements capable of satisfying PCS and IMT-2000 services at the same time.

Also, by forming a gap between coupling slots in the ground plane and reducing the size of the gap to reduce the deterioration of the reflection loss characteristic when extending a single antenna to an array antenna, the reflection loss characteristics at low frequencies Another object of the present invention to provide a wideband array antenna having a desired frequency bandwidth by improving the.

1 shows a configuration of a 1x4 array antenna in which a single antenna designed as a form of a flat antenna is used.

FIG. 2 is a cross-sectional view showing an XY cross section of the antenna structure shown in FIG. 1. FIG.

3 is a structural diagram illustrating an aperture coupling antenna having a multi-layer structure having a parasitic element according to a preferred embodiment of the present invention.

4 is a cross-sectional view showing a cross-sectional structure of the XY axis of the antenna structure shown in FIG.

5 is a graph showing a change in reflection loss characteristic according to a change in the size of a gap.

6 shows radiation patterns at a center frequency of 1.8 GHz of PCS and a center frequency of 2.15 GHz of IMT-2000.

<Description of the symbols for the main parts of the drawings>

11: radiating element 12: parasitic element

13 coupling slot 14 ground plane

15 feeder 16 conductor plate

21: third dielectric substrate 22: third foam material

23: second dielectric substrate 24: second foam material

25: first dielectric substrate 26: first foam material

31: gap

In order to achieve the above object, the present invention provides a parasitic element formed under the third dielectric substrate, a third foam material for extending the bandwidth formed under the parasitic element, and a radiating element formed under the third foam material. And a second dielectric substrate formed under the radiating element, a second foam material for extending bandwidth formed under the second dielectric substrate, and a current formed under the second foam material and excited from the feed line to the electrical coupling. A ground plane formed between the coupling slot supplied to the radiating element and the coupling slot and having a gap for improving the reflection loss characteristic of the array antenna, and a first dielectric substrate and a first dielectric substrate formed below the ground plane. Feed line is installed in the lower portion of the feed line, the first foam material and the conductive plate formed on the lower portion of the first foam material to reduce the rear radiation All.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention may be easily implemented by those skilled in the art in detail.

First of all, in adding reference numerals to the components of the angular surface, it should be noted that the same components have the same reference numerals as much as possible even though they are shown in different drawings.

3 is a structural diagram showing an aperture coupling antenna having a multi-layer structure having a parasitic element according to a preferred embodiment of the present invention, Figure 4 is a cross-sectional view showing a cross-sectional structure of the XY axis of the antenna structure shown in FIG.

3 and 4, the structure of the preferred 1 × 4 array antenna according to the present invention is a parasitic element 12 for extending the bandwidth of the lower portion of the third dielectric substrate 21 to have a size of 4.6 cm × 5.25 cm. The third foam material 22 is formed under the parasitic element 12 to have a thickness of 16 mm to expand the bandwidth.

The radiating element 11 has a size of 5.72 cm × 5.3 cm below the third foam material 22, and the second dielectric substrate 23 having a dielectric constant of 2.17 and a thickness of 30 mil is formed below the radiating element 11. In the lower portion of the second dielectric substrate 23, a second foam material 24 for bandwidth expansion is formed to a thickness of 10 mm. At this time, it is preferable that the space | interval between each radiation element 11 shall be 9 cm.

In the design of the array antenna and the 0.37cm × 4cm coupling slot 13 which supplies the current excited from the feed line 15 to the radiating element 11 by the electrical coupling under the second foam material 24. A ground plane 14 having a gap 31 having a size of 0.4 cm by 9 cm is formed on the surface to improve reflection loss characteristics.

In addition, a first dielectric substrate 25 is formed below the ground plane 14, a feed line 15 is provided below the first dielectric substrate 25, and a 42-mm-thick first foam is provided below the feed line 15. The material 26 is formed, and the lower portion of the first foam material 26 is formed with a conductor plate 16 having a size of 43 cm x 15 cm to reduce back radiation. The rear radiation characteristics can be improved by adjusting the size of the conductor plate 16 to reduce the rear radiation.

The current excited by the feed line 15 located at the bottom of the first dielectric substrate 25 is transferred to the radiating element 11 by electrical coupling through the coupling slot 13, the radiating element 11 and the radiating element ( The bandwidth can be extended due to the effect of the electrical coupling with the parasitic element 12 located above the 11). In this case, the bandwidth can be adjusted by changing the size of the parasitic element 12.

In addition, the second foam material 24 and the third foam material 22 are also formed to obtain broadband characteristics, and a conductor for reducing rear radiation below the first foam material 26 having a thickness of about lambda / 4 is formed. 16) is formed.

The gap 31 located between the coupling slots 13 adjusts its size to reduce the deterioration of the characteristics of the reflection loss occurring in the design of the array antenna. Since the coupling between the elements decreases as the distance between the radiating elements 11 increases, the reflection loss characteristic does not change significantly compared to the reflection loss characteristic of a single antenna, but the side lobe level characteristics deteriorate much.

Therefore, according to a preferred embodiment of the present invention, the spacing between the radiating elements 11 is 9cm, the electrical length is 0.54 lambda at 1.8 GHz, the center frequency of PCS, and electrical at 2.05 GHz, the center frequency of IMT-2000. As the length is 0.62 lambda and the electrical length between radiating elements is relatively short at PCS center frequency, when it is extended to array antenna, the return loss characteristic at low frequency is worsened by coupling phenomenon between radiating elements. Return loss characteristics at frequency can be improved by varying the size of the gap 31 between the coupling slots 13.

FIG. 5 is a graph showing a change in return loss characteristic according to a change in the size of the gap 31. Referring to this, it can be seen that the return loss characteristic at a low frequency is not good until the gap 31 is formed. 31), we can see that the return loss at low frequencies is improved.

In addition, as shown in FIG. 5, the bandwidth of the antenna is 600 MHz (reflection loss -17 dB or less) at a voltage standing wave ratio of 1.3 or less (reflection loss -17 dB or less) so that the PCS and IMT-2000 can be used for both services.

6 shows radiation patterns at a center frequency of 1.8 GHz of PCS and a center frequency of 2.15 GHz of IMT-2000.

The direction of the main beam was inclined by 6 degrees at each frequency, and the side lobe level was below -21 dB at the center frequency of PCS at 1.8 GHz, and the back emission was below -25 dB. This was -20dB and the rear emission was -30dB or less.

As mentioned above, although preferred embodiments of the present invention have been described in detail, those of ordinary skill in the art to which the present invention pertains should realize the present invention without departing from the spirit and scope of the present invention as defined in the appended claims. It will be appreciated that various modifications or changes can be made. Accordingly, modifications to future embodiments of the present invention will not depart from the technology of the present invention.

According to the present invention, the gap between the coupling slots is improved to reduce the reflection loss characteristics caused by the coupling between radiating elements, thereby improving the reflection loss characteristics at low frequencies, and having a voltage standing wave ratio of 1.3 or less (reflection loss of -17 dB). It can be used as a PCS and IMT-2000 service from 600MHz (1.7GHz to 2.3GHz) at the following) to reduce the overlapping investment such as manufacturing cost and installation cost, and the problem of environmental beautification due to the difficulty of antennas in urban areas. It is a useful invention with the advantages to be solved.

Claims (12)

A third dielectric substrate, a parasitic element for bandwidth extension formed under the third dielectric substrate, a third foam material for bandwidth extension formed under the parasitic element, and a lower portion of the third foam material A radiating element formed, a second dielectric substrate formed under the radiating element, a second foam material for extending bandwidth formed under the second dielectric substrate, and a lower portion formed under the second foam material A multilayer structure comprising a ground plane, a first dielectric substrate formed under the ground plane, a feed line provided under the first dielectric substrate, and a conductor plate for reducing back radiation formed under the feed line. In the aperture coupled antenna of The ground plane is formed between a coupling slot for supplying current excited by the feed line to the radiating element through electrical coupling, and a coupling slot formed between the coupling slots to improve reflection loss characteristics generated when the antenna is extended to an array antenna. And a slot shaped gap. The microstrip antenna structure according to claim 1, wherein the parasitic element has a size of 4.6 cm x 5.25 cm. The microstrip antenna structure of claim 1, wherein the third foam material is 16 mm thick. The microstrip antenna structure of claim 1, wherein the radiating element has a size of 5.72 cm x 5.3 cm. 2. The microstrip antenna structure of claim 1, wherein the second dielectric substrate has a dielectric constant of 2.17 and a thickness of 30 mils. The microstrip antenna structure of claim 1, wherein the coupling slot has a size of 0.37 cm x 4 cm. delete 7. The microstrip antenna structure according to any one of claims 1 to 6, wherein the gap has a size of 0.4 cm x 9 cm. 2. The microstrip antenna structure according to claim 1, wherein the thickness of the second foam material is 10 mm. The microstrip antenna structure as claimed in claim 1, wherein the thickness of the first foam material is 42mm. The microstrip antenna structure according to claim 1, wherein the conductor plate has a size of 43 cm x 15 cm. The microstrip antenna structure according to claim 1, wherein the spacing between said radiating elements is 9 cm.