JPH03110904A - Parabolic antenna system for circularly polarized wave - Google Patents

Abstract

PURPOSE:To reduce the manufacture cost with simple constitution by arranging a circularly polarized wave loop antenna near a focus of a parabolic reflecting mirror in a way that the loop face is opposite to the parabolic reflecting mirror and arranging a reflector opposite to the said parabolic reflecting mirror with respect to the circularly polarized wave loop antenna. CONSTITUTION:In the structure of a circularly polarized wave loop antenna 11, a conductor loop 17 is arranged to one face of a dielectric base 18, and 1st and 2nd microstrip lines 18, 19 are arranged, which tie two points A, B whose included angle is 90 deg. on the conductor loop 17 and a center of the loop being a feeding point. A main lob MB of the circularly polarized wave loop antenna 11 is generated strongly toward a parabolic reflection mirror 10 as shown in dotted lines by the provision of the reflection plate 14. Then an electromagnetic wave of a circularly polarized wave reflected and focused by a parabolic reflecting mirror 10 and going to a focus F is received efficiently by the circularly polarized wave loop antenna 11, and a circularly polarized wave is converted into a linearly polarized wave via the 1st and 2nd microstrip lines 18, 19 and propagated to a converter 13 via a coaxial line 12 from the feeding point.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a circularly polarized parabolic antenna device used for transmitting and receiving microwave communications, receiving satellite broadcasting, etc. This is a simple configuration of the primary radiator.

(Prior Art) As shown in FIG. 9, a conventional parabolic antenna device for circularly polarized waves uses a waveguide circuit 1 as a -order radiator to convert the circularly polarized wave of a received signal of, for example, 120H2 into a linearly polarized wave. The signal is then frequency-converted to approximately IGH by the converter 2, and is appropriately guided to communication equipment via a coaxial line (not shown). The waveguide circuit 1 and the converter 2 have relatively large dimensions, and if they are installed in front of the parabolic reflector 3, the antenna gain will be reduced due to blocking. Therefore, as shown in FIG. 9, in the case where the waveguide circuit 1 is used, the parabolic reflecting mirror 3 is numerically constructed of an offset type.

Furthermore, as shown in FIG. 10, there is also a circularly polarized antenna as a negative-order radiator with a back-fur helical coil 4 structure. This backfire helical coil 4 is connected to a coaxial line 6 to a regular circular parabolic reflector 5.
Power is supplied by a center foot type, and connected to a converter 7 provided on the back side of the parabolic reflector 5. This backfire helical coil 4 has a relatively small size, less blocking, and a relatively high antenna gain. If the opening area is the same, the size of the perfect circular parabolic reflecting mirror 5 can be made smaller than that of the offset type.

(Problems to be Solved by the Invention) By the way, the waveguide circuit 1 as a primary radiator as shown in FIG. It requires a converter, has a complicated circuit configuration, and is expensive as a whole.

Furthermore, the antenna gain of the backfire helical coil 4 as a primary radiator as shown in FIG. 1O is greatly affected by the dimensional accuracy of the pitch angle and circumference of the helical coil. Therefore, high precision is required during manufacturing, resulting in high manufacturing costs.

The present invention has been made in view of the above-mentioned circumstances of the conventional parabolic antenna device for circularly polarized waves, and provides a parabolic antenna device for circularly polarized waves using a primary radiator that can be manufactured with a simple configuration and high dimensional accuracy. The purpose is to

(Means for Solving the Problems) In order to achieve the above object, the parabolic antenna device for circularly polarized waves of the present invention includes a conductor loop disposed on a substrate, and a conductor loop having an included angle of 90 degrees. A circularly polarized loop antenna is formed by using a 90 degree phase shifter on one of the two paths connecting the two points and the feeding point so that the signal phase is shifted by 90 degrees, and the circular polarization loop antenna is formed near the focal point of the parabolic reflector. A polarized loop antenna is arranged so that its loop surface faces the parabolic reflector, and a reflector is arranged on the opposite side of the circularly polarized loop antenna from the parabolic reflector.

In addition, a conductor loop is placed on the board, and the phase of the signal is changed to 90 degrees via a 90 degree phase shifter on one of the two paths connecting two points with an included angle of 90 degrees and the feeding point. A circularly polarized loop antenna is formed so as to be shifted by a degree, a sub-reflector is placed near the focal point of the parabolic reflector, and the circularly polarized loop antenna is placed near the focal point of the sub-reflector and near the front of the parabolic reflector. The loop surface may be arranged so as to face the sub-reflector.

It is also possible to configure the parabolic reflector to have a perfect circular shape, and to feed power to the circularly polarized loop antenna via a coaxial line in a center feed type.

Furthermore, the conductor loop made of conductor foil is formed on one surface of the dielectric substrate, one end of the coaxial line is connected to this dielectric substrate, and an included angle is formed between the connection point of the center conductor and the conductor loop. The phase of the signal propagated between two points at 90 degrees is 9
Connecting two microstrip lines with different lengths by a 0 degree deviation, forming a ground plate on the other surface of the Kamaki dielectric substrate so as to face the microstrip line inside the conductor loop, The ground plate may be configured by connecting the outer conductor of the coaxial line.

Furthermore, between the connection point of the center conductor of the coaxial line and the two points having an included angle of 90 degrees between the conductor loop, two microstrip lines having different lengths are used so that the phase of the propagated signal is shifted by 90 degrees. Instead of connecting, the dielectric substrate and another dielectric are placed in the path of one microstrip line, and the same l1id+ as the two points of the conductor loop is placed.
It is also possible to configure the two paths connecting the connection points of the center conductors of the line so that the phases of the signals are shifted by 90 degrees.

(Function) First, the parabolic antenna device for circularly polarized waves according to claim 1 is configured such that the phase of the signal is shifted by 90 degrees between two points with an included angle of 90 degrees in the conductor loop and two paths between the feeding point. Since a circularly polarized loop antenna is formed, the configuration of the -order radiator is extremely simple. By arranging the reflector, the main lobe of this circularly polarized loop antenna is strongly generated only in the direction of the parabolic reflector, making it possible to efficiently receive the electromagnetic waves reflected by the parabolic reflector and efficiently transmit the electromagnetic waves. It can be reflected well and transmitted.

Further, in the circularly polarized wave parabolic antenna device according to the second aspect of the present invention, the circularly polarized wave loop antenna is arranged near the front surface of the parabolic wave reflector, so that the parabolic wave reflector acts as a reflector of the circularly polarized wave loop antenna. Moreover, the distance between the parabolic reflector and the circularly polarized loop antenna is small, and the feed line is extremely short.

In the circularly polarized wave parabolic antenna device according to claim 3, since the circularly polarized loop antenna itself is small in size,
Even the center-feed type has little effect on blocking.

Therefore, a center-feed type regular circular parabolic antenna with high antenna gain can be obtained.

Furthermore, in the parabolic antenna device for circularly polarized waves according to claim 4, the conductor loops, microstrip lines, etc. that form the circularly polarized loop antenna can be manufactured with high dimensional accuracy in the same process by etching, printing, etc. .

Furthermore, in the parabolic antenna device for circularly polarized waves according to claim 5, since a dielectric body other than the dielectric substrate is disposed in the path of the microstrip line, the dielectric constant and thickness of this dielectric body are The speed of electromagnetic waves propagating through the microstrip line can be adjusted according to the width, and the phase difference between the signals between the two points of the conductor loop and the feeding point can be finely adjusted.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a side sectional view showing an outline of an embodiment of the parabolic antenna device for circularly polarized waves of the present invention, and FIG. 2 is a partially cutaway view showing the structure of the circularly polarized loop antenna in FIG. FIG. 3 is a plan view of an example of the circularly polarized loop antenna in FIG. 2, and FIG. 4 is a cross-sectional view taken along the line X--X in FIG. 3.

In FIGS. 1 to 4, a circularly polarized loop antenna 11 as a -order radiator is placed near the focal point F of a perfectly circular parabolic reflector 10 with its loop surface facing the parabolic reflector @10. . This circularly polarized loop antenna 11 is fed with power in a center feed type, and is fed to the coaxial line 1.
One end of 2 is connected. Note that the other end of the coaxial line 12 is
Converter 13 placed on the back side of the parabolic reflector IO
connected to. Roughly speaking, a reflector plate 14 as a reflector is located on the opposite side of the circularly polarized loop antenna 11 from the parabolic reflector IO.
They are placed parallel to the loop plane and separated by 4 to 1/2 wavelengths. These circularly polarized loop antenna 11 and reflector 14 are
As shown in Figure 2, the radome I5 also serves as a support member.
fixedly placed by

Incidentally, the structure of the circularly polarized loop antenna 11 is such that a conductor loop 17 is arranged on one surface of a dielectric substrate 16, and two points A and B with an included angle of 90 degrees are connected to the conductor loop I7. First and second microstrip lines 18 and 19 are arranged to connect the centers of the loops, which are feeding points. Then, a conductor loop 17 is placed on the other surface of the dielectric substrate I6.
A concentric small-diameter ground plate 20 is arranged inside of it so as not to face it. These conductor loops 17
The first and second microstrip lines 18, 19, and the ground plate 20 are formed by the same process by etching, printing, etc. conductive foil made of copper or the like. Here, the circumferential length of the conductor loop 17 is approximately 1.2 wavelengths of the signal. Also, for the first microstrip line 18, a second
The microstrip line 19 is formed to be longer by 1/4 wavelength of the signal, and acts as a 90 degree phase shifter.
The phase of the signal is shifted by 90 degrees between points A and B of the conductor loop 17 and the central feeding point. Furthermore, a hole 21 is bored in the center of the dielectric substrate 16 as a feeding point, and a ground plate 20
The center conductor 22 of the coaxial line 12 passes through the hole 2I from the side and is electrically connected to the first and second microstrip lines 18, 19 by soldering or the like. Further, the outer conductor 23 of the coaxial line 12 is electrically connected to the ground plate 20 by soldering or the like.

In such a configuration, the main lobe MB of the circularly polarized loop antenna 11 is
As shown by the dotted line in the figure, the light is strongly generated toward the parabolic reflector 10. Therefore, the circularly polarized electromagnetic waves that are reflected and focused by the parabolic reflector 10 and directed toward the focal point F are efficiently received by the circularly polarized loop antenna 11, and further transmitted via the first and second microstrip lines 18 and 19. The circularly polarized wave is converted into a linearly polarized wave and propagated from the feeding point to the converter 13 via the coaxial line I2. Here, the diameter of the reflecting plate 14 may be as small as about 0.4 wavelength of the signal, specifically 1
The diameter is 1 cm for a received signal of 2GH. Therefore, there is little influence from blocking, and the diameter of 30cm
A practically sufficient antenna gain for receiving satellite broadcasting can be obtained with the parabolic reflector 10. Furthermore, since the circularly polarized loop antenna II can be formed in one step by etching or printing, it has good dimensions and bulk, is suitable for mass production, and is advantageous in reducing manufacturing costs.

The reflector 1 constitutes a kind of loop Yagi antenna, and a loop-shaped conductor may be used instead of the reflector I4. Therefore, if a loop-shaped conductor as a reflector is formed by etching or the like on another substrate, then both the reflector and the circularly polarized loop antenna 11 are formed by etching or the like on their respective substrates. Therefore, it can be constructed extremely lightweight, which is advantageous in terms of structural mechanics. In addition, it is sufficient that the phases of the propagated signals are 90 degrees apart in the two paths connecting the two points A and B of the conductor loop 17 and the feeding point.
The feeding point is not limited to the center of the loop. The conductor loop 17 is not limited to a perfect circle, but may be an ellipse to transmit and receive elliptically polarized waves. Additionally, the direction of rotation of the circularly polarized waves transmitted and received by the circularly polarized loop antenna 11 can be changed by swapping the left and right points of point B with respect to point A in FIG.

Other examples of circularly polarized loop antennas used in the circularly polarized parabolic antenna device of the present invention are shown in FIGS. 5 and 6.

FIG. 5 is a plan view thereof, and FIG. 6 is a Y--
It is a sectional view taken along the Y arrow. In FIGS. 5 and 6, the same members as those in FIGS. 3 and 4 are given the same reference numerals, and redundant explanations will be omitted.

The structures shown in FIGS. 5 and 6 differ from the structures shown in FIGS. 3 and 4 in the following points. That is, in the structure shown in FIGS. 5 and 6, the first and second microstrip lines 18.30 connecting the center of the loop and points A and B of the conductor loop 17 have the same length. be. Then, a dielectric material 3 is placed covering the path of one of the second microstrip lines 30.

In such a configuration, the speed of the electromagnetic waves propagated through the second microstrip line 30 decreases depending on the dielectric constant, thickness, and width of the dielectric 31. Therefore, the circularly polarized loop antenna 32 is formed by setting the dielectric 31 so that the signal propagation from points A and B to the center is out of phase by exactly 90 degrees. Here, dielectric 3
If the thickness or width of 1 is adjusted, it is possible to finely adjust the phase difference in the two paths between the two points A and B and the feeding point, even after manufacturing.

In the embodiments shown in FIGS. 5 and 6, the dielectric material 31 is arranged to cover the second microstrip line 30, but a dielectric material with a high dielectric constant is arranged directly on the dielectric substrate 16. , a second microstrip line may be formed over this dielectric. Then, the second microstrip line is connected to the first stripline 1.
The path is longer than 8, and the speed of the electromagnetic wave is slowed down by the dielectric material having a high dielectric constant, making it easy to obtain a large phase difference between the two paths connecting the two points A and B and the feeding point.

FIG. 7 is a side sectional view schematically showing another embodiment of the circularly polarized parabolic antenna device of the present invention of an offset type. In FIG. 7, the same members as those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

In FIG. 7, a circularly polarized loop antenna II is placed near the focal point of an offset parabolic reflector 40 with its loop surface facing the parabolic reflector 40. As shown in FIG. Further, a reflector 14 is placed behind and slightly apart from the circularly polarized loop antenna 11, and a converter 3 is integrally placed behind the reflector 14.

The circularly polarized loop antenna 11 and the converter 13 are fed with power through the coaxial line 12. In addition, a rose reflector 4
The converter 13 and the like are supported and fixed by an arm 41 extending from the back side of the converter 0.

In such a configuration, blocking does not occur, so
The reflective plate 14 can have a large area. Then,
The circularly polarized loop antenna 11 has an extremely small antenna gain toward the side opposite to the parabolic reflection m40, and only the reflected wave from the parabolic reflection fi40 is received by the circularly polarized loop antenna II, and the direct wave that becomes noise is not received. Not done. In addition, a circularly polarized loop antenna 11 and a converter 1
3, the length of the coaxial line 12 becomes extremely short, and the attenuation between them is extremely small, which improves the antenna gain accordingly.

FIG. 8 shows the parabolic antenna device for circularly polarized waves of the present invention.
FIG. 7 is a side sectional view showing an outline of yet another embodiment of a 737 reflector antenna. In FIG. 8, the same members as those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

In the 'fJS diagram, a sub-reflector m50 is arranged near the focal point F of a regular circular parabolic reflector IO, and the focus of this sub-reflector 50 is configured to be near the parabolic reflector 10.

In addition, near the focal point of this sub-reflector 50 and 1/4 to 1/2 wavelength of the received signal in front of the front surface of the parabolic reflector 10, a circularly polarized loop antenna 11 sub-reflects the loop surface.
50. Power is supplied via a coaxial line 12 between this circularly polarized loop antenna 1 and a converter 13 disposed on the back side of the parabolic reflector lO. Roughly speaking, in front of the circularly polarized loop antenna 11, a loop-shaped conductor 51 as a waveguide is separated by about one wavelength of the signal.
are arranged with their loop surfaces parallel. The sub-reflector 50 and the loop-shaped conductor 51 as a waveguide are appropriately supported and fixed by a radome (not shown) which also serves as a support member together with the circularly polarized loop antenna II.

In such a configuration, a large area parabolic reflector lO
is used as a reflector, and the loop-shaped conductor 51 roughly acts as a waveguide, making the directivity of the main lobe MB narrow as shown by the dotted line in FIG. can be received efficiently. Furthermore, the circularly polarized loop antenna 11 is only slightly away from the parabolic reflector 10, and the coaxial line 12 is extremely short.

The loop-shaped conductor 51 serving as a waveguide narrows the directivity as a so-called loop Yagi antenna, and if necessary, a plurality of them may be arranged with their loop surfaces parallel. Further, although the antenna shown in FIG. 8 is a Cassegrain antenna, it may be a D'Agorian antenna.

In such a double-reflector antenna, the double-reflector 5
In order for 0 to act as a reflecting mirror, it is said that the diameter of the signal must be at least 10 wavelengths. Therefore, the present embodiment is useful in a parabolic antenna device equipped with a parabolic reflector lO having a diameter of 100 wavelengths or more of signals in which the influence of blocking by the double reflector 50 is reduced.

Furthermore, although the above embodiments have mainly been explained regarding the reception of circularly polarized wave signals, it goes without saying that the circularly polarized wave parabolic antenna device of the present invention can transmit circularly polarized wave signals.

(Effects of the Invention) Since the present invention is configured as described above, it produces the special effects described below.

First, in the parabolic antenna device for circularly polarized waves according to the first aspect, the circularly polarized loop antenna as the -order radiator has a simple configuration, and the manufacturing cost can be reduced. Moreover, since the main lobe is directed towards the parabolic reflector, the reflected waves from the parabolic reflector can be efficiently received.

In addition, in the parabolic antenna device for circularly polarized waves according to the second aspect, the parabolic reflector having a large area can be used as a reflector for the circularly polarized loop antenna. Moreover, the circularly polarized loop antenna is placed close to the parabolic reflector, making the feed line extremely short, and the antenna gain is improved by the amount of attenuation between the lines.

In the parabolic antenna device for circularly polarized waves according to claim 3, the circumferential length of the circularly polarized loop antenna is about 1.2 wavelengths of the received signal, which is a small diameter, and the influence of blocking is reduced. If the aperture area is the same, it is possible to construct a center-feed type parabolic antenna device with a high antenna gain compared to an offset type.

Furthermore, in the parabolic antenna device for circularly polarized waves according to claim 4, since the circularly polarized loop antenna can be formed in the same process by etching, printing, etc., the shape and dimensions of the antenna can be manufactured with high precision. There is no variation in gain, making it suitable for mass production. Moreover, the manufacturing cost is low.

Furthermore, in the parabolic antenna device for circularly polarized waves according to claim 5, the thickness and width of the dielectric material are adjusted to provide two points connecting the feeding point and two points shifted by 90 degrees of the conductive material loop. The phase difference of signals between paths can be finely adjusted.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an outline of an embodiment of the circularly polarized parabolic antenna device of the present invention, and FIG. 2 is a partially cutaway view showing the structure of the circularly polarized loop antenna in FIG. FIG. 3 is a plan view of an example of the circularly polarized loop antenna in FIG. 2, FIG. 4 is a cross-sectional view taken along the line xx in FIG. 3, and FIG. 6 is a plan view of another example of the circularly polarized loop antenna used in the parabolic antenna device for circularly polarized waves of the present invention, FIG. FIG. 8 is a side sectional view showing an outline of another embodiment in which the parabolic antenna device for circularly polarized waves of the present invention is an offset type, and FIG. FIG. 9 is a side sectional view showing an outline of yet another embodiment as a reflector antenna, and FIG. 9 is a side sectional view showing an example of an offset-type conventional circularly polarized wave parabolic antenna device using a waveguide circuit. Figure 1O is
1 is a side sectional view showing an example of a conventional center-feed type circularly polarized parabolic antenna device using a backfire helical coil. lO: Perfect circular parabolic reflector, 11.32: Circularly polarized loop antenna, 12: Coaxial line, 14: Reflector, 16: Dielectric substrate, 17:
Conductor loop, 18: first microstrip line, 19.30: second microstrip line,
20 Nigerland plate, 22: center conductor, 23: outer conductor, 31: dielectric, 40: offset parabolic reflector, 50: sub-reflector, F: focal point.

Claims (1)

[Claims] 1. A conductor loop is arranged on the substrate, and the conductor loop connects two points with an included angle of 90 degrees and a feeding point.2.
The phase of the signal is 90 degrees through a 90 degree phase shifter on one of the two paths.
A circularly polarized loop antenna is formed by shifting 0 degrees,
The circularly polarized loop antenna is arranged near the focal point of the parabolic reflector so that the loop surface faces the parabolic reflector, and a reflector is arranged on the opposite side of the circularly polarized loop antenna from the parabolic reflector. A parabolic antenna device for circularly polarized waves, characterized in that it is configured by arranging. 2. Place a conductor loop on the board, and use this conductor loop to connect two points with an included angle of 90 degrees to the power supply point.
The phase of the signal is 90 degrees through a 90 degree phase shifter on one of the two paths.
A circularly polarized loop antenna is formed by shifting 0 degrees,
A sub-reflector is arranged near the focus of the parabolic reflector, and the circularly polarized loop antenna is arranged near the focus of the sub-reflector and near the front of the parabolic reflector so that the loop surface faces the sub-reflector. A parabolic antenna device for circularly polarized waves, characterized in that it is configured as follows. 3. The parabolic antenna device for circularly polarized waves according to claim 1, wherein the parabolic reflecting mirror has a perfect circular shape, and is configured to feed power to the circularly polarized loop antenna in a center feed type via a coaxial line. Parabolic antenna device for circularly polarized waves. 4. In the circularly polarized parabolic antenna device according to any one of claims 1 to 3, the conductive loop made of conductive foil is formed on one surface of a dielectric substrate, and a coaxial line is formed on this dielectric substrate. One end is connected, and two microstrip lines of different lengths are connected between the connection point of the center conductor and the two points with an included angle of 90 degrees between the conductor loop and the phase of the propagated signal by 90 degrees. forming a ground plate on the other side of the dielectric substrate so as to face the microstrip line inside the conductor loop;
A parabolic antenna device for circularly polarized waves, characterized in that the ground plate is connected to the outer conductor of the coaxial line. 5. In the parabolic antenna device for circularly polarized waves according to claim 4, the phase of the signal propagated between two points having an included angle of 90 degrees between the connection point of the center conductor of the coaxial line and the conductor loop is 90 degrees. Instead of connecting two microstrip lines with different lengths by the amount of deviation, the dielectric substrate and another dielectric are placed in the path of one microstrip line, and the two points of the conductor loop are connected. 1. A parabolic antenna device for circularly polarized waves, characterized in that the signal phase is shifted by 90 degrees between two paths connecting the connecting point of a center conductor of a coaxial line.