JP3038205B1 - Waveguide-fed planar antenna - Google Patents

Abstract

Kind Code: A1 An object of the present invention is to provide a waveguide-fed planar antenna that has a simple structure and is highly efficient and that can be shared by two frequencies. A short side of a feed waveguide using a rectangular waveguide is arranged in parallel, and a plurality of radiating elements are provided on an upper surface of each feed waveguide. A T-shaped probe 6 is provided below each radiating element 2 and inserted into the feeding waveguide 1. In this case, the probe 6 is inserted into the feeding waveguide 1 through a slit 11 provided on the upper surface of the feeding waveguide 1 at a right angle to the waveguide axis direction. In the case where power is supplied to the frequencies f1 and f2 that are relatively distant from each other with one configuration, power is supplied by arranging the f1 power supply waveguides 4 and the f2 power supply waveguides 5 alternately. In this case, the f1 radiating element has a ground plane on the outer surface of the f2 feeding waveguide 5, and the f2 radiating element has a ground plane on the outer surface of the f1 feeding waveguide 4, so that a two-frequency shared planar antenna is used. Is configured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide-fed flat antenna used for satellite broadcasting and communication, for example.

[0002]

2. Description of the Related Art Conventionally, in many cases where a planar antenna is formed, a large number of radiating elements such as patch antennas and helical antennas are arranged to form an antenna. FIG. 7 shows an example of the configuration of a waveguide-fed flat antenna that feeds power by arranging the long sides of a rectangular waveguide in parallel. FIG.
It is sectional drawing of the planar antenna. In FIG. 7, reference numeral 1 denotes a feeding waveguide using a rectangular waveguide, and the long sides of the feeding waveguide 1 are arranged in parallel. A plurality of radiating elements 2 are provided on the upper surface of each feed waveguide 1 at predetermined intervals. As shown in FIG. 8, a linear probe 3 is provided below each of the radiating elements 2 and inserted into the feed waveguide 1.

In the waveguide-fed flat antenna shown in FIG. 7, the feeding of frequencies f1 and f2 which are relatively separated from each other is performed by one.
In the case of a single-sheet configuration, power is supplied by arranging every other f1 power supply waveguide 4 and f2 power supply waveguide 5 as shown in FIG. In this case, the element for f1 is the feeding waveguide 5 for f2.
Is used as a ground plane, and the f2 element is used as a ground plane on the external surface of the f1 feed waveguide 4, so that a relatively high-efficiency planar antenna sharing two frequencies can be constructed in principle.

[0004]

However, according to the literature on planar antennas, for example, "Latest Plane Antenna Technology" by Haneishi et al., A planar antenna having a large number of elements arranged has an element spacing of about one wavelength (λ). If it becomes larger, unnecessary radiation, which is a grating lobe, is generated, and the antenna efficiency is extremely reduced. The long side of a normal rectangular waveguide (standard size) is about 0.9 wavelength as shown in FIG. 8, but the element spacing of the f1 and f2 dual-frequency antennas is one feed waveguide. Since the wavelengths are arranged every other wavelength, the wavelength is doubled to about 1.8 wavelengths. As a result, the above-described grating lobe is generated, and a highly efficient planar antenna cannot be realized.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a waveguide-fed planar antenna which has a simple structure and is highly efficient and which can be used in two frequencies.

[0006]

According to a first aspect of the present invention, in a waveguide-fed type planar antenna, a plurality of feeding waveguides each formed of a rectangular waveguide are arranged in parallel in the short side direction, A plurality of radiating elements provided at predetermined intervals on an upper short side surface of the feeding waveguide; and a plurality of radiating elements corresponding to the respective radiating elements on the upper short side surface of each of the feeding waveguides and in the waveguide axial direction. A slit provided at a right angle and one end connected to each of the above radiating elements
It is, the other end; and a T-shaped or L-shaped probe inserted into the feeding waveguide from said slit, said plurality
Means for arranging the feed waveguides in parallel
The corresponding first and second feed waveguides are alternately arranged.
And features.

[0007]

According to a second aspect of the present invention, in the waveguide-fed planar antenna according to the first aspect, a groove having a depth of about 1/4 wavelength is provided at a boundary between the feeding waveguides arranged in parallel. It is characterized by the following.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a waveguide-fed flat antenna with a rectangular waveguide long side parallel arrangement according to an embodiment of the present invention, and FIG. 2 is a sectional view of the same. As shown in FIG. 1, short sides of a feeding waveguide 1 using a rectangular waveguide are arranged in parallel, and a plurality of helical radiating elements, for example, of a helical type are arranged on the upper surface of each feeding waveguide 1 at predetermined intervals. 2 is provided. A T-shaped probe 6 is provided below the radiating element 2 as shown in FIGS. 2 and 3, and is inserted into the feeding waveguide 1. In this case, as shown in FIG. 4, a slit 11 is provided on the upper surface (short side surface) of the feeding waveguide 1 at a position corresponding to each radiating element 2 at right angles to the waveguide axis direction, The element 2 can be inserted into the feeding waveguide 1 through the slit 11. When the probe 6 is inserted from the short side surface of the rectangular waveguide, a T-shaped probe 6 is used because a simple pin type does not couple with an electric field in the waveguide and cannot supply power. 3 is an enlarged view showing the shape of the T-shaped probe 6, and FIG. 4 is a plan view in the direction of arrow a in FIG. The probe 6 may be an L-shaped probe in addition to a T-shaped probe. Further, by providing the slit 11 at right angles to the waveguide axis direction, it is possible to prevent the emission of radio waves from the slit. Further, the width of the slit 11 only needs to be able to insert the probe 6 and can be set to a value very small as compared with the wavelength of the radio wave to be used, so that the emission of the radio wave can be effectively prevented from this point as well.

By providing the slit 11 on the upper surface of the feed waveguide 1 as described above, the probe 6 is inserted into the feed waveguide 1 through the slit 11 from the outside as shown in FIGS. Therefore, the radiating element 2 and the probe 6 can be integrally formed in advance.

In the waveguide-fed planar antenna shown in FIG. 1, when power is supplied to frequencies f1 and f2 which are relatively distant by a single sheet, as shown in FIG.
The power supply waveguides 4 for f2 and the power supply waveguides 5 for f2 are arranged alternately to supply power. In this case, the element for f1 has a ground plane on the outer surface of the feeding waveguide 5 for f2, and the element for f2 has a ground plane on the outer surface of the feeding waveguide 4 for f1, thereby forming a two-frequency planar antenna. I do.

With the above configuration, it is possible to prevent the generation of grating lobes and obtain a highly efficient waveguide-fed planar antenna. That is, as shown in FIG. 2, since the short side of the rectangular waveguide is generally about 0.45 wavelength, the short sides of the feeding waveguide 1 using the rectangular waveguide are arranged in parallel to form the radiation element. 2, the element spacing becomes 0.9 wavelength and the element spacing becomes one wavelength even in the dual frequency band shared antenna in which the f1 feeding waveguide 4 and the f2 feeding waveguide 5 are fed alternately. No grating lobes are generated because they can be suppressed to below.

Since the size of the rectangular waveguide of the standard size is set so as to be suitable for broadband transmission, the ratio of the long side to the short side is 2: 1. If the cut-off frequency is set to be limited to the band used, the long side of the rectangular waveguide can be shorter than the standard size. Although the short side also depends on the impedance of the radiating element, if the impedance of the waveguide can be increased, the short side can be shorter than the short side of the standard-size rectangular waveguide.

Further, when the radiating elements of the frequencies f1 and f2 cause a large current coupling on the outer surface of the waveguide (ground plate) and disturb the directivity, thereby lowering the antenna efficiency, as shown in FIG. The boundary of the feed waveguide at f2, ie, f
The distance between the feeding waveguide 4 for 1 and the feeding waveguide 5 for f2 is about 1 /
Four-wavelength grooves (choke) 12 are provided to suppress mutual current coupling.

As described above, the provision of the groove 12 of about 1/4 wavelength at the boundary between the power supply waveguides 4 and 5 for the frequencies f1 and f2 suppresses current coupling with each other and improves antenna efficiency. Can be.

(Embodiment) Next, an embodiment of the present invention will be described. FIG. 6 shows an embodiment of the waveguide-fed flat antenna according to the present invention, in which the transmission frequency f1 = 14.0 to 14.5.
Right-handed circular polarization of GHz and reception frequency f2 = 12.25
This shows an example of a case where a planar antenna shared by two frequency bands using left circularly polarized waves of 12.75 GHz is configured.

As shown in FIG. 6, right-handed helical elements 21 are mounted on the feed waveguide 4 for f1 at intervals of about 17 mm.
Similarly, a left-handed helical element 22 is attached to the f2 feed waveguide 5 at an interval of about 19 mm. The feed waveguides 4 for f1 and the feed waveguides 5 for f2 are alternately arranged in parallel, and the feed waveguides 4 for f1 are arranged in parallel with each other.
It is combined into one system by one branch waveguide 23, and the f1 terminal 2
4 is connected. Further, the f2 feed waveguide 5 is combined into one system by the f2 branch waveguide 25 and connected to the f2 terminal 26. The f1 terminal 24 and the f2 terminal 26 are configured using a plug or the like. The right-handed helical element 21 and the left-handed helical element 22 have a T-shaped or L-shaped probe 6 as shown in FIGS.
Is connected and inserted into the f1 feed waveguide 4 or the f2 feed waveguide 5 through the slit 11.

The antenna efficiency of the planar antenna configured as described above with respect to the entire feeding waveguide area is such that the right-handed helical element 21 also utilizes the surface of the f2 feeding waveguide 5 and, conversely, the left-handed helical element 22 uses Since the surface of the feed waveguide 4 for f1 is also used, an efficiency of 50% or more can be obtained even if the feed waveguide loss is included. Even if the antenna efficiency is 100% when the transmitting antenna and the receiving antenna are separated, the same antenna performance can be obtained with a smaller area, and the size and cost of the product can be reduced.

In the case where the directions of rotation of the polarizations of the frequencies f1 and f2 are the same, that is, if both the frequencies f1 and f2 are right-handed or left-handed, the right-handed helical element 21 of the frequencies f1 and f2 is used. A current generated on the surfaces of the f1 feed waveguide 4 and the f2 feed waveguide 5 may be coupled to the electromagnetic field from the left-handed helical element 22 to reduce the antenna efficiency. As described above, by providing the groove 12 of about 1/4 wavelength (about 5 to 7 mm) at the boundary between the feed waveguides 4 and 5, coupling can be suppressed and the antenna efficiency can be improved.

[0021]

As described above in detail, according to the present invention, in the waveguide-fed planar antenna, the short sides of the rectangular feeding waveguides are arranged in parallel, and each feeding waveguide is arranged. The radiating elements are mounted on the upper surface of the radiating element at predetermined intervals, and a T-shaped or L-shaped probe connected to the radiating element is inserted into the feeding waveguide.
Even when a planar antenna shared by two frequency bands is configured by alternately arranging feed waveguides for f2 and f2, the spacing between radiating elements can be suppressed to one wavelength or less to prevent the generation of grating lobes, and a highly efficient planar An antenna can be configured.

Further, a slit is provided at right angles to the waveguide axis direction on the short side surface of the feeding waveguide, and a probe can be inserted from this slit portion. The probe and the radiating element can be integrated, and a planar antenna can be easily manufactured even when a T-shaped or L-shaped probe is used.

In a waveguide-fed planar antenna in which short sides of rectangular waveguides are arranged in parallel, a depth of about １ ／ wavelength is provided at the boundary between the f1 feeding waveguide and the f2 feeding waveguide. By providing the groove, the current coupling between them can be suppressed and the antenna efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a waveguide-fed flat antenna having a parallel arrangement of rectangular waveguide short sides according to an embodiment of the present invention.

FIG. 2 is a sectional view of the waveguide-fed planar antenna according to the embodiment;

FIG. 3 is an enlarged view showing a main part including a probe in the embodiment.

FIG. 4 is a plan view in the direction of arrow a in FIG. 3;

FIG. 5 is a sectional view of a waveguide-fed flat antenna according to another embodiment of the present invention.

FIG. 6 is a plan view showing an embodiment of a waveguide-fed flat antenna according to the present invention.

FIG. 7 is a perspective view of a conventional waveguide-fed flat antenna having a parallel arrangement of long sides of a rectangular waveguide.

8 is a sectional view of the waveguide-fed planar antenna shown in FIG. 7;

[Explanation of symbols]

 Reference Signs List 1 feeding waveguide 2 radiating element 3 linear probe 4 feeding waveguide for f1 5 feeding waveguide for f2 6 T-shaped probe 11 slit 12 groove (choke) 21 right-handed helical element 22 left-handed helical element 23 f1 branch waveguide Tube 24 f1 terminal 25 f2 branch waveguide 26 f2 terminal

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikihiro Matsuura 1406 Hasunuma, Omiya City, Saitama Prefecture Yagi Antenna Co., Ltd. Omiya Plant (56) References JP-A-11-308019 (JP, A) JP-A-7- 154134 (JP, A) JP-A-62-207003 (JP, A) JP-A-5-160610 (JP, A) JP-A-52-10656 (JP, A) Japanese Utility Model Publication No. 57-28503 (JP, U) 1994 IEICE Spring Conference B-50 (58) Fields surveyed (Int. Cl. ⁷ , DB name) H01Q 21/00-21/30 H01Q 13/08 H01P 5/103 JICST file (JOIS) WPI ( DIALOG)

Claims (2)

(57) [Claims] 1. A waveguide-fed planar antenna, comprising: means for arranging a plurality of rectangular waveguides in parallel with short-side directions of the plurality of rectangular waveguides; A plurality of radiating elements provided at predetermined intervals; a slit corresponding to the radiating element on the upper short side surface of each of the feed waveguides and provided at right angles to the waveguide axis direction; A T-shaped or L-shaped probe having one end connected to the element and the other end inserted into the feeding waveguide from the slit , and arranging the plurality of feeding waveguides in parallel;
The means comprises first and second power supply leads corresponding to different frequencies.
A waveguide-fed planar antenna, wherein wave tubes are alternately arranged . 2. The waveguide-fed planar antenna according to claim 1, wherein a groove having a depth of about １ ／ wavelength is provided at a boundary between the feeding waveguides arranged in parallel.