JP2007142570A - Patch array antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve directive characteristics that are symmetrical in electric- and magnetic-field directions when arranging a plurality of wideband and compact patch antennas using a parasitic element and a short-circuiting pin. <P>SOLUTION: There are patch antennas 10A-10D that are arranged symmetrically in the direction of an electric field, and further are arranged symmetrically in the direction of a magnetic field. The patch antennas 10A and 10C, and 10B and 10D connect a patch element 13 by a first feeder line 16 mutually. The first feeder line 16 is connected by the second feeder line 17 mutually. The first feeder line 16 is arranged outside a center line L1 in the patch antenna. A second feeder line 17 is arranged on a line L3 deviating from the center line L2 by a 1/4 wavelength, an impedance matching line 18 for impedance matching is arranged at both the ends, and a feeding point 19 is arranged in the middle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a patch array antenna having a wide band, a small size, and good directivity characteristics.

  A patch antenna 20 having a configuration shown in FIG. 3 is known as a patch antenna that is reduced in size and increased in bandwidth (see, for example, Non-Patent Document 1). This is because the lower surface of the dielectric substrate 21 is covered with the ground conductor 22, the patch element 23 is formed on the upper surface, the parasitic element 25 is formed above the patch element 23 via another dielectric 24, and the patch element 23. Further, the length of the parasitic element 25 in the electric field direction is set to 1/4 wavelength (λg1 / 4, λg2 / 4) at the design frequencies f1 and f2, respectively, and a short-circuit pin 27 is disposed at the end opposite to the power supply pin 26. The grounding conductor 22, the patch element 23, and the parasitic element 25 are connected by the short-circuit pin 27. This is because the short-circuit pin 27 is provided at the minimum electric field point to reduce the size in the electric field direction and to reduce the size, and the length of the parasitic element 25 in the electric field direction is made shorter than that of the patch element 23 to resonate the parasitic element 25. The frequency is shifted from the resonance frequency of the patch element 23 to achieve a wider band. The power supply pin 26 may be configured not to be directly connected to the parasitic element 25.

On the other hand, a patch array antenna 30 shown in FIG. 4 is known as a method for arraying patch antennas (see, for example, Patent Document 1). In FIG. 4, the lower surface of the dielectric substrate 31 is covered with a ground conductor 32, a plurality of patch elements 33 are arranged on the upper surface, and power is supplied to each patch element 33 through a feed line 34. As described above, by arranging the patch elements 33 arranged in the electric field direction symmetrically with respect to the direction perpendicular to the electric field direction, it is possible to give good directivity characteristics, and if the arrangement interval is further reduced, wide directivity can be obtained. It can have characteristics.
Girish Kumar, KPRay, "Broadband Microstrip Antennas" Artech House, p239-242, 2003 JP-A-11-266118

  However, as shown in FIG. 3, when a patch antenna having a short-circuit pin and a parasitic element to increase the bandwidth and reduce the size is developed into an array structure as shown in FIG. 4, the patch antenna shown in FIG. Since the directional characteristic pattern for a is asymmetric, there is a problem that a good directional characteristic cannot be obtained if it is simply arrayed.

  An object of the present invention is to provide a patch array antenna in which a patch antenna having a short-circuit pin and a parasitic element to achieve a wide band and a small size is arrayed so as to obtain good directivity characteristics.

In order to solve the above-mentioned problems, in the invention according to claim 1, a ground conductor is formed on the lower surface of the dielectric substrate, a patch element is formed on the upper surface of the dielectric substrate, and a parasitic element is formed above the patch element. Forming the length of the patch element and the parasitic element in the electric field direction to a quarter wavelength at the respective design frequency, and the end of the patch element opposite to the feeding point is the ground conductor and the parasitic element A patch array antenna in which one patch antenna is configured by short-circuiting with a short-circuit pin, and the patch antennas are arranged in an array, and the two patch antennas are arranged in an electric field direction so that the short-circuit pin is on the outside And a linear first feed line connecting the patch elements to each other between the two patch antennas, and any one of the two patch antennas from an intermediate point. The position shifted by 1/4 wavelength on one of the patch antenna side, characterized in that so as to supply power to the first feed line as a feeding point.
According to a second aspect of the present invention, in the patch array antenna according to the first aspect, the first feeding line is disposed at a position shifted from a central line common to the two patch antennas, and the feeding point and the An impedance matching line for impedance matching is arranged between the first feeder line and the first feeder line.
According to a third aspect of the present invention, in the patch array antenna according to the first or second aspect, the two patch antennas are arranged side by side so as to be symmetrical with respect to the center line in the electric field direction. A linear second feed line that connects the first feed lines to each other at the feed point line is disposed.

  According to the present invention, even if a patch antenna is designed to have a wide band and a small size by using a short-circuit pin and a parasitic element, a plurality of arrays can be arranged to achieve a wide band and a small size. The resulting patch array antenna can be realized.

  FIG. 1 is a perspective view of a patch array antenna 10 according to one embodiment of the present invention, and FIG. 2 is a plan view. Reference numeral 11 denotes a dielectric substrate, the lower surface of which is covered with a ground conductor 12, a patch element 13 is formed on the upper surface, and the length in the electric field direction is patched on the upper surface of the patch element 13 via a dielectric (not shown). A parasitic element 14 that is shorter than the length of the element 13 is formed, thereby constituting a single patch antenna 10A to 10D. The length of the patch element 13 and the parasitic element 14 in the electric field direction is 1/4 wavelength (λg1 / 4, λg2 / 4) at the design frequencies f1 and f2. The patch array antenna 10 is configured by arranging the four patch antennas 10A to 10D in an array. In each of the patch antennas 10A to 10D, the ground conductor 12, the patch element 13, and the parasitic element 14 are connected by a plurality of short-circuit pins 15. The patch antennas 10A and 10C, 10B and 10D arranged symmetrically in the electric field direction so that the short-circuit pin 15 is on the outside are connected to the patch element 13 by the first feed line 16, respectively. 16 are connected by a second feed line 17, but impedance matching lines 18 are arranged on the connection side (both sides) of the feed line 17 with the feed line 16. Reference numeral 19 denotes a feeding point disposed on the second feeding line 18 at a position intersecting with the center line L0. A central conductor of a coaxial line for feeding, for example, is connected to the lower surface of the dielectric substrate 12. The outer conductor of the coaxial line is connected to the ground conductor 12. The patch antennas 10A and 10B, 10C and 10D are arranged symmetrically with respect to the center line L0.

  The first feed line 16 changes from the center line L1 to the left side (outside) on the patch antennas 10A and 10C side, and changes from the center line L1 to the right side (outside) on the patch antennas 10B and 10D side. This is because the impedance matching line 18 for impedance matching is inserted. Although the impedance matching line 18 shown in FIGS. 1 and 2 is small, a large space is formed here, so that a relatively large impedance matching line can be disposed here. As described above, since each patch antenna 10A to 10D is fed from a point deviating from the center line L1, the directivity characteristic in the magnetic field direction is asymmetric in a single patch antenna. However, since the patch antennas 10A, 10B, 10C, and 10D are arranged symmetrically with respect to the center line L0, the patch array antenna can realize directional characteristics that are symmetrical with respect to the magnetic field direction.

  Further, the second feed line 17 in which the feed point 19 is arranged is not symmetrically arranged with respect to the center line L2, but is ¼ wavelength (resonant frequency f1 of the patch element 13) with respect to the center line L2. And the parasitic element 14 are arranged on a line L3 shifted by a quarter wavelength (λg3 / 4) of the wavelength of the frequency f3 intermediate between the resonance frequencies f2. As a result, and because the patch antennas 10A and 10C, 10B and 10D are symmetrical, the feeding from the feeding point 19 to the patch antennas 10A and 10B and the feeding to the patch antennas 10C and 10D are performed in the same phase. Excited in phase, the directivity in the electric field direction is also symmetric.

  As described above, when arranging a plurality of patch antennas which are provided with the parasitic element 14 and the short-circuit pin 15 to achieve a wide band and a small size, it is possible to realize a directivity characteristic symmetric with respect to the electric field direction and the magnetic field direction.

  In FIG. 1 and FIG. 2, when the patch array antenna is configured by two patch antennas 10A and 10C, the first feed line 16 is disposed on the center line L1, and the feed point 19 is the first feed point 19 thereof. What is necessary is just to arrange | position at the point which cross | intersects the line L3 on the feeder line 16. FIG. Even in this configuration, the directivity is symmetric in the magnetic field direction and the electric field direction. When impedance matching is necessary, the second feeding line 17 is provided, the feeding point 19 is arranged thereon, and the impedance matching line 18 is arranged as shown in FIGS. 1 and 2, but at this time The directional characteristics in the magnetic field direction are not symmetric.

It is a perspective view of the patch array antenna of the Example of this invention. It is a top view of the patch array antenna of the same Example. (a) is a plan view of a conventional patch antenna, and (b) is a cross-sectional view taken along the direction of the electric field. It is a perspective view of the conventional patch array antenna.

Explanation of symbols

10: Patch array antenna, 10A to 10D: Patch antenna, 11: Dielectric substrate, 12: Ground conductor, 13: Patch element, 14: Parasitic element, 15: Short-circuit pin, 16: First feed line, 17: First 2 feed line, 18: impedance matching line, 19: feed point, 20: patch antenna, 21: dielectric substrate, 22: ground conductor, 23: patch element, 24: dielectric, 25: parasitic element, 26: feed pin 27: short-circuit pin 30: patch array antenna, 31: dielectric substrate, 32: ground conductor, 33: patch element, 34: feed line

Claims (3)

A ground conductor is formed on the lower surface of the dielectric substrate, a patch element is formed on the upper surface of the dielectric substrate, a parasitic element is formed above the patch element, and the lengths of the patch element and the parasitic element are set in the electric field direction. Are set to 1/4 wavelength at each design frequency, and one patch antenna is configured by short-circuiting the end of the patch element opposite to the feeding point to the ground conductor and the parasitic element with a short-circuit pin, A patch array antenna in which the patch antennas are arranged in an array,
The two patch antennas are arranged symmetrically along the direction of the electric field so that the short-circuit pins are on the outside, and the first linear feed that connects the patch elements to each other between the two patch antennas A line is arranged, and power is fed to the first feed line at a position shifted by a quarter wavelength from the midpoint of the two patch antennas to one of the patch antennas. A patch array antenna characterized by. The patch array antenna according to claim 1, wherein
The first feed line is disposed at a position shifted from a central line common to the two patch antennas, and an impedance matching line for impedance matching is disposed between the feed point and the first feed line. A patch array antenna characterized by that. The patch array antenna according to claim 1 or 2,
Two sets of the two patch antennas are arranged side by side so as to be symmetric with respect to the center line in the electric field direction, and the first feed line on both sides is connected to each other via the feed point line. A patch array antenna having a feed line.

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