CA1037155A - Reflector antenna - Google Patents
Reflector antennaInfo
- Publication number
- CA1037155A CA1037155A CA204,614A CA204614A CA1037155A CA 1037155 A CA1037155 A CA 1037155A CA 204614 A CA204614 A CA 204614A CA 1037155 A CA1037155 A CA 1037155A
- Authority
- CA
- Canada
- Prior art keywords
- subreflector
- primary radiator
- main reflector
- curve
- vertical plane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Landscapes
- Aerials With Secondary Devices (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A reflector antenna useful in a radar apparatus is provided with a subreflector so as to produce a primary radiator of relatively large aperture diameter which decreases the adver-se affects of the atmosphere. The subreflector includes a curved reflecting surface having a vertical plane with a curvature therein different from that in a horizontal plane whereby the antenna directs a beam of radio frequency that has a greater width in the vertical plane compared to the horizontal plane, even though a primary radiator emitting a rotationally symmetrical beam is employed.
A reflector antenna useful in a radar apparatus is provided with a subreflector so as to produce a primary radiator of relatively large aperture diameter which decreases the adver-se affects of the atmosphere. The subreflector includes a curved reflecting surface having a vertical plane with a curvature therein different from that in a horizontal plane whereby the antenna directs a beam of radio frequency that has a greater width in the vertical plane compared to the horizontal plane, even though a primary radiator emitting a rotationally symmetrical beam is employed.
Description
The present invention relates to a reflector antenna useful in a radar apparatus, and moYe particularly to a reflec-tor antenna including a subreflector.
~ eflector antennas having composite curves such as a doubly-curved reflector on a main reflector surface are known. A
conventional reflector antenna having composite curves generally comprises a main reflector and a primary radiator, an aperture in the primary radiator being commonly covered with a dielectric co-ver.
During transmission a beam emitted from the primary radiator is reflected by the main reflector and radiates out in-to space~
The surface of the main reflector of the antenna has composite curves composed of a central sectional curve and trans-verse curves. The central sectional curve is determined by the shape of the beam in the vertical plane of said beam whilst the c~rves that are transverse to the central sectional curve are pa-raboloid having a focus point in the phase center of the primary radiator.
In the foregoing antenna, a focal distance to the diame-ter of the aperture of the main reflector cannot be too long, in order that a broad beam should be obtained from the primary ra-diator. Accordingly, the primary radiator emitting the beam should have an aperture having a diameter corresponding to 1-3 wave lengths. Thus, when the primary radiator is used in a high frequency band such as a millimeter wave band, the aperture of the primary radiator will be quite small. Therefore, when a rain drop or a particle of snow is deposited on the dielectric cover covering the aperture of the primary radiator, attenuation effects become quite high, so that the conventional reflector antenna ~an not be operated in the millimeter or higher wave bands.
10;~71SS
The length of the aperture of the main reflector ih the vertical plane is different from that of the horizontal plane.
Accordingly, the angular aperture of the main reflector in the vertical plane should be different from that of the horizontal plane. Thus, only a horn having a different diameter in the ver-tical plane compared to he horizontal plane can be employed as the primary radiator.
A principal objective of the present invention is to overcome the above mentioned disadvantages of a conventional reflector antenna.
The present invention relates to a reflector antenna for directing a beam of radio frequency energy and includes a main reflector having a central sectional curve and transverse composite curves of two dimensional curves, the antenna being characterized by a subreflector in the beam path between a pri-mary radiator and the main reflector whereby the beam radiated from the primary radiator is a narrow beam and the aperture of the primary radiator is relatively large. Attenuation effects prQduced by depositing a rain drop or a particle of ice or snow on the primary radiator are reduced together with other trans-mission problems commonly encountered in the millimeter wave band.
The subreflector has a curvature in a vertical plane and in a horizontal plane which can be changed so as to produce a beam having a different width in the vertical plane and in the horizon-tal plane~ even though a rotationally symmetrical beam is radia-ted from the primary radiator. Accordingly, even though the primary radiator has a rotationally symmetrical structure and produces a rotationally symmetrical beam for circular-polariza-tion use or orthogonal dual-polarization use, the power radiated from said primary radiator can be effectively intercepted by the main reflector.
The invention will now be more particularly described 1037~55 with reference to embodiments thereof shown, by way of example, in the accompanying drawings, wherein:
Figure 1 is a perspective view of a conventional reflec-tor antenna;
Figure 2 is a perspective view of a main reflector shown in the antenna of Figure l;
Figure 3 is a perspective view of one embodiment of a reflector antenna in accordance with the present invention;
Figure 4(a) is a front elevation view of another em-bodiment of a reflector antenna in accordance with the presentinvention;
Figure 4(b) is a side elevation view of the embodiment of Figure 4(a);
Figure 4(c) is a plan view of the embodiment of Figure 4(a);
Figure 5(~) is a front elevation view of still another embodiment of a reflector antenna in accordance with the present invention;
Figure 5(b) is a side elevation view of the embodiment of Figure 5(a); and Figure 5(c) is a plan view of the embodiment of Figure 5(a)-Figure 1 illustrates a known reflector antenna havinga main reflector 1 that is driven by a beam of radio frequency energy emitted from a primary radiator 2 having a phase center - F. A dielectric cover 3 closes an outlet aperture of the radiator
~ eflector antennas having composite curves such as a doubly-curved reflector on a main reflector surface are known. A
conventional reflector antenna having composite curves generally comprises a main reflector and a primary radiator, an aperture in the primary radiator being commonly covered with a dielectric co-ver.
During transmission a beam emitted from the primary radiator is reflected by the main reflector and radiates out in-to space~
The surface of the main reflector of the antenna has composite curves composed of a central sectional curve and trans-verse curves. The central sectional curve is determined by the shape of the beam in the vertical plane of said beam whilst the c~rves that are transverse to the central sectional curve are pa-raboloid having a focus point in the phase center of the primary radiator.
In the foregoing antenna, a focal distance to the diame-ter of the aperture of the main reflector cannot be too long, in order that a broad beam should be obtained from the primary ra-diator. Accordingly, the primary radiator emitting the beam should have an aperture having a diameter corresponding to 1-3 wave lengths. Thus, when the primary radiator is used in a high frequency band such as a millimeter wave band, the aperture of the primary radiator will be quite small. Therefore, when a rain drop or a particle of snow is deposited on the dielectric cover covering the aperture of the primary radiator, attenuation effects become quite high, so that the conventional reflector antenna ~an not be operated in the millimeter or higher wave bands.
10;~71SS
The length of the aperture of the main reflector ih the vertical plane is different from that of the horizontal plane.
Accordingly, the angular aperture of the main reflector in the vertical plane should be different from that of the horizontal plane. Thus, only a horn having a different diameter in the ver-tical plane compared to he horizontal plane can be employed as the primary radiator.
A principal objective of the present invention is to overcome the above mentioned disadvantages of a conventional reflector antenna.
The present invention relates to a reflector antenna for directing a beam of radio frequency energy and includes a main reflector having a central sectional curve and transverse composite curves of two dimensional curves, the antenna being characterized by a subreflector in the beam path between a pri-mary radiator and the main reflector whereby the beam radiated from the primary radiator is a narrow beam and the aperture of the primary radiator is relatively large. Attenuation effects prQduced by depositing a rain drop or a particle of ice or snow on the primary radiator are reduced together with other trans-mission problems commonly encountered in the millimeter wave band.
The subreflector has a curvature in a vertical plane and in a horizontal plane which can be changed so as to produce a beam having a different width in the vertical plane and in the horizon-tal plane~ even though a rotationally symmetrical beam is radia-ted from the primary radiator. Accordingly, even though the primary radiator has a rotationally symmetrical structure and produces a rotationally symmetrical beam for circular-polariza-tion use or orthogonal dual-polarization use, the power radiated from said primary radiator can be effectively intercepted by the main reflector.
The invention will now be more particularly described 1037~55 with reference to embodiments thereof shown, by way of example, in the accompanying drawings, wherein:
Figure 1 is a perspective view of a conventional reflec-tor antenna;
Figure 2 is a perspective view of a main reflector shown in the antenna of Figure l;
Figure 3 is a perspective view of one embodiment of a reflector antenna in accordance with the present invention;
Figure 4(a) is a front elevation view of another em-bodiment of a reflector antenna in accordance with the presentinvention;
Figure 4(b) is a side elevation view of the embodiment of Figure 4(a);
Figure 4(c) is a plan view of the embodiment of Figure 4(a);
Figure 5(~) is a front elevation view of still another embodiment of a reflector antenna in accordance with the present invention;
Figure 5(b) is a side elevation view of the embodiment of Figure 5(a); and Figure 5(c) is a plan view of the embodiment of Figure 5(a)-Figure 1 illustrates a known reflector antenna havinga main reflector 1 that is driven by a beam of radio frequency energy emitted from a primary radiator 2 having a phase center - F. A dielectric cover 3 closes an outlet aperture of the radiator
2.
Figure 2 illustrates the reflector 1 in greater detail.
A central sectional curve la is determined by the slope of the beam in the vertical plane thereof whilst a plurality of curves lb that are transverse to the curve la are paraboloid and have a focus point in the phase center F of the radiator 2.
Figure 2 illustrates the reflector 1 in greater detail.
A central sectional curve la is determined by the slope of the beam in the vertical plane thereof whilst a plurality of curves lb that are transverse to the curve la are paraboloid and have a focus point in the phase center F of the radiator 2.
- 3 '~0;~7155 Figure 3 shows one embodiment of the reflector antenna of the invention, having composite curves wherein the reference numeral 1 also designates a main reflector; 2 designates a prima-ry radiator; 3 designates a dielectric cover and 4 designates a subreflector. The surface of the main reflector 1 is formed by the central sectional curve la and the curves lb which are trans-verse to said curve la. The surface of the subreflector 4 is for-med by a central sectional curve 4a and a group of curves 4b which are transverse to the curve 4a. The central sectional curve 4a of the subreflector 4 is a hyperbola whose focuses are F2 and a phase center Fl of the primary radiator 2. The group of curves 4b which are transverse to said sectional curve 4a of the subreflector 4 are hyperboloid whose focuses are Fl and F3. The focus F3 is on a line F2Sl, and the position of F3 is shifted by the position of Sl. On the other hand, the central sectional curve la of the main reflector 1 is a special curve to provide a beam in the plane comprising the curves and the focus F2, and reflect a beam emitted from a point Sl on the central sectional curve 4a of the subref-lector 4 to a point Ml on the central sectional curve la of the main reflector 1 in the directon M~Pl.
The group of curves lb which are transverse to the central sectional curve la of the main reflector 1 are paraboloid, having focus F3 and are in the plane MlM2P2Pl which is transverse to the plane comprising the central sectional curve la.
In accordance with the reflector system having the com-posite curve surface, a beam emitted in a predetermined plane from the primary radiator 2, such as the beam radiated to Sl and S2 on the subreflector 4, is reflected to Ml and M2 on the main reflector 1 and is reflected from the main reflector 1 to Pl and P2. The beam transmitted from Ml and M2 on the main reflector 1 into ~ space, has the same phase at PlP2, whereby a narrow beam is present in the plane MlM2P2Pl. In accordance with this system, an angle subtend~d by the subreflector 4 in the beam emitted from ~ 037155 the primary radiator 2 can be selected at the discretion of an operator. Accordingly, the beam e~itted from the primary radiator 2 can be relatively narrow, and the aperture of the primary radi-ator 2 can be relatively large, whereby the characteristics of the antenna are not substantially changed in the event that there is deposited a rain drop or a snow particle on the dielectric cover 3 which is placed over the aperture of the primary radiator 2. In this embodiment, the central sectional curve 4a of the subreflec-tor 4 and the curves 4b which are transverse to said curve 4a are 1~ hyperboloid. However, the curves can be various two dimensional curves such as an ellipse for example.
Referring to Figure 4, another embodiment of the inven-tion is illustrated wherein the primary radiator is a horn having a rectangular aperture. The reference numeral 11 designates a main reflector having an aperture of different size in a vertical plane as compared to the horizontal plane, and whose surface is paraboloid with focus Fl. The numeral 14 designates a subreflec-tor whose surface is hyperboloid having focuses Fl and F2 while Cv and ~h respectively represent angular radiation apertures of the main reflector 11 in a vertical plane and horizontal plane of the subreflector 14 and 12 designates a primary radiator having a rectangular aperture emitting the beam having angles ~Cv and ~h in the vertical plane and horizontal plane respectively.
The phase center corresponds to the focus F2.
` During transmission from an antenna having the foregoing structure, the beam emitted from the primary radiator 12 is ref-lected from the subreflector 14 and from the main reflector 11 as shown by the broken lines, and then transmitted into space. In the case of receiving a transmitted beam, a reverse route is fol-~0 lowed. It is thus possible to use the antenna of the invention for both transmission and reception.
The beam emitted from the primary radiator 12 can be 103~7~55 made narrow by selecting suitable curves of the subreflector 14 while the aperture of the primary radiator 12 can be relatively large. In general, howèver, the horn having a rectangular aper-ture provides a beam of different width when excited by a verti-cally polarized wave and a horizontally polarized wave. According-ly, it is not suitable for dual orthogonally polarized waves and circularly polarized waves.
The other embodiment of the invention shown in Figure S reduces the foregoing disadvantages. In this figure~ the refe-rence numeral 11 designates a main reflector; 22 designates a pri-mary radiator; and 24 designates a subreflector.
During transmission, the beam emitted from the primary radiator 22 is reflected by the subreflector 24 and the main ref-lector 11 out into space as shown by the broken lines. In order to produce a different beam width in a vertical plane compared to the horizontal plane, the diameter Dv in the vertical plane of the main reflector 11 is different from the diameter Dh in the horizontal plane.
The beam width of the beam emitted from the primary ra-diator 22 is the same in both the vertical plane and horizontalplane. Thus, the angle ~ subtended by the subreflector 24 in the vertical plane is equal to that of the horizontal plane.
In order to radiate the beam emitted from the primary radiator 22 onto the subreflector 24 and then to the main reflec-tor 11 which has a different aperture diameter in the vertical plane compared to the horizontal plane, the beam transmitted to the main reflector 11 in the vertical plane is changed from that of the horizontal plane. In order to produce a beam having a different beam width, the positions of the focuses in the verti-cal plane and in the horizontal plane are shifted by the mainreflector 11 and the subreflector 24 to the positions FlV and Flh as shown in Figure 5. As illustrated in Figure 5(c) the main reflector 11 is shown by the parabola having a focus Flh, and the subreflector 24 is shown by the hyperbola having focuses ~037~55 F~h and F2. On the other hand, according to Figure 5(b) the main reflector 11 is shown by the parabola having a focus FlV and the subreflector 24 shown by the hyperbola having focuses FlV and F2.
In the planes between the horizontal plane and the vertical plane, the positions of possible focuses of the main reflector 11 are selected from the range FlV to Flh.
In the horizontal plane and vertical plane, the focus is shifted between FlV and Flh, so that a rotationally symmetri-cal beam having a beam width ~ , the beam being emitted from the primary radiator 22, can be shifted by the subreflector 24 to give ~ v in the vertical plane and 1 h in the horizontal plane.
The beam is therefore effectively radiated to the main reflector 11. It is thus possible to employ a primary radiator which emits a rotationally symmetrical beam.
Although the case for transmission has been described, the case for receiving a beam of radio frequency energy should be clearly understood from the preceding remarks.
It will be noted that although the subreflector 24 having a hyperbolic sectional form has been described, a subreflector hàving an elliptic sectional form can be used in the invention.
As stated above, in accordance with the invention it is possible to employ a primary radiator having a relatively large aperture in a reflector antenna, having composite curves.
As a result, deleterious ~ c in antenna characteristic caused by a deposited rain drop or snow particle~on a dielectric cover covering the aperture of the primary radiator can be advantagous-ly prevented.
In accordance with the invention, it is also possible to employ a primary radiator having a rotationally symmetrical beam and excellent polarization characteristics whereby the ex-cellent polarization characteristics can be maintained even though a~c~r6~
the reflector *~nna has an aperture of different diameter in a vertical plane co~p~red to the horizontal plane.
The group of curves lb which are transverse to the central sectional curve la of the main reflector 1 are paraboloid, having focus F3 and are in the plane MlM2P2Pl which is transverse to the plane comprising the central sectional curve la.
In accordance with the reflector system having the com-posite curve surface, a beam emitted in a predetermined plane from the primary radiator 2, such as the beam radiated to Sl and S2 on the subreflector 4, is reflected to Ml and M2 on the main reflector 1 and is reflected from the main reflector 1 to Pl and P2. The beam transmitted from Ml and M2 on the main reflector 1 into ~ space, has the same phase at PlP2, whereby a narrow beam is present in the plane MlM2P2Pl. In accordance with this system, an angle subtend~d by the subreflector 4 in the beam emitted from ~ 037155 the primary radiator 2 can be selected at the discretion of an operator. Accordingly, the beam e~itted from the primary radiator 2 can be relatively narrow, and the aperture of the primary radi-ator 2 can be relatively large, whereby the characteristics of the antenna are not substantially changed in the event that there is deposited a rain drop or a snow particle on the dielectric cover 3 which is placed over the aperture of the primary radiator 2. In this embodiment, the central sectional curve 4a of the subreflec-tor 4 and the curves 4b which are transverse to said curve 4a are 1~ hyperboloid. However, the curves can be various two dimensional curves such as an ellipse for example.
Referring to Figure 4, another embodiment of the inven-tion is illustrated wherein the primary radiator is a horn having a rectangular aperture. The reference numeral 11 designates a main reflector having an aperture of different size in a vertical plane as compared to the horizontal plane, and whose surface is paraboloid with focus Fl. The numeral 14 designates a subreflec-tor whose surface is hyperboloid having focuses Fl and F2 while Cv and ~h respectively represent angular radiation apertures of the main reflector 11 in a vertical plane and horizontal plane of the subreflector 14 and 12 designates a primary radiator having a rectangular aperture emitting the beam having angles ~Cv and ~h in the vertical plane and horizontal plane respectively.
The phase center corresponds to the focus F2.
` During transmission from an antenna having the foregoing structure, the beam emitted from the primary radiator 12 is ref-lected from the subreflector 14 and from the main reflector 11 as shown by the broken lines, and then transmitted into space. In the case of receiving a transmitted beam, a reverse route is fol-~0 lowed. It is thus possible to use the antenna of the invention for both transmission and reception.
The beam emitted from the primary radiator 12 can be 103~7~55 made narrow by selecting suitable curves of the subreflector 14 while the aperture of the primary radiator 12 can be relatively large. In general, howèver, the horn having a rectangular aper-ture provides a beam of different width when excited by a verti-cally polarized wave and a horizontally polarized wave. According-ly, it is not suitable for dual orthogonally polarized waves and circularly polarized waves.
The other embodiment of the invention shown in Figure S reduces the foregoing disadvantages. In this figure~ the refe-rence numeral 11 designates a main reflector; 22 designates a pri-mary radiator; and 24 designates a subreflector.
During transmission, the beam emitted from the primary radiator 22 is reflected by the subreflector 24 and the main ref-lector 11 out into space as shown by the broken lines. In order to produce a different beam width in a vertical plane compared to the horizontal plane, the diameter Dv in the vertical plane of the main reflector 11 is different from the diameter Dh in the horizontal plane.
The beam width of the beam emitted from the primary ra-diator 22 is the same in both the vertical plane and horizontalplane. Thus, the angle ~ subtended by the subreflector 24 in the vertical plane is equal to that of the horizontal plane.
In order to radiate the beam emitted from the primary radiator 22 onto the subreflector 24 and then to the main reflec-tor 11 which has a different aperture diameter in the vertical plane compared to the horizontal plane, the beam transmitted to the main reflector 11 in the vertical plane is changed from that of the horizontal plane. In order to produce a beam having a different beam width, the positions of the focuses in the verti-cal plane and in the horizontal plane are shifted by the mainreflector 11 and the subreflector 24 to the positions FlV and Flh as shown in Figure 5. As illustrated in Figure 5(c) the main reflector 11 is shown by the parabola having a focus Flh, and the subreflector 24 is shown by the hyperbola having focuses ~037~55 F~h and F2. On the other hand, according to Figure 5(b) the main reflector 11 is shown by the parabola having a focus FlV and the subreflector 24 shown by the hyperbola having focuses FlV and F2.
In the planes between the horizontal plane and the vertical plane, the positions of possible focuses of the main reflector 11 are selected from the range FlV to Flh.
In the horizontal plane and vertical plane, the focus is shifted between FlV and Flh, so that a rotationally symmetri-cal beam having a beam width ~ , the beam being emitted from the primary radiator 22, can be shifted by the subreflector 24 to give ~ v in the vertical plane and 1 h in the horizontal plane.
The beam is therefore effectively radiated to the main reflector 11. It is thus possible to employ a primary radiator which emits a rotationally symmetrical beam.
Although the case for transmission has been described, the case for receiving a beam of radio frequency energy should be clearly understood from the preceding remarks.
It will be noted that although the subreflector 24 having a hyperbolic sectional form has been described, a subreflector hàving an elliptic sectional form can be used in the invention.
As stated above, in accordance with the invention it is possible to employ a primary radiator having a relatively large aperture in a reflector antenna, having composite curves.
As a result, deleterious ~ c in antenna characteristic caused by a deposited rain drop or snow particle~on a dielectric cover covering the aperture of the primary radiator can be advantagous-ly prevented.
In accordance with the invention, it is also possible to employ a primary radiator having a rotationally symmetrical beam and excellent polarization characteristics whereby the ex-cellent polarization characteristics can be maintained even though a~c~r6~
the reflector *~nna has an aperture of different diameter in a vertical plane co~p~red to the horizontal plane.
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A reflector antenna which comprises:
a primary radiator for generating a rotationally symmetrical beam;
a main reflector having a composite curved surface formed by a central sectional curve determined by the shape of a beam in a vertical plane and a parabola transverse to the curve, said central and parabolic surfaces having spaced focal points;
a subreflector having a composite curved surface formed by a central sectional two dimensional curve and a group of two dimensional curves transverse to the central sectional curve;
wherein the subreflector has a hyperbolic curve having focus. corresponding to a phase center of the primary radiator and to the focus of the parabola transverse to the central sectional curve of the surface of the main reflector.
a primary radiator for generating a rotationally symmetrical beam;
a main reflector having a composite curved surface formed by a central sectional curve determined by the shape of a beam in a vertical plane and a parabola transverse to the curve, said central and parabolic surfaces having spaced focal points;
a subreflector having a composite curved surface formed by a central sectional two dimensional curve and a group of two dimensional curves transverse to the central sectional curve;
wherein the subreflector has a hyperbolic curve having focus. corresponding to a phase center of the primary radiator and to the focus of the parabola transverse to the central sectional curve of the surface of the main reflector.
2. A reflector antenna which comprises:
a primary radiator for generating a rotationally symmetrical beam;
a main reflector having a different aperture diameter in the vertical plane to that of the horizontal plane, and a subreflector having a curved surface to convert a spherical wave to a wave having a different curvature in the vertical plane to that of the horizontal plane to permit the beam to be effectively intercepted by the main reflector;
wherein the main reflector has parabolic curves having a different focus in the vertical plane to that of the horizontal plane, the subreflector has hyperbolic curves having focuses corresponding to a phase center of the primary radiator and to the focus of a vertical parabolic curve of the main reflector in the vertical plane, and the subreflector has hyperbolic curves having focuses corresponding to a phase center of the primary radiator and to the focus of a horizontal parabolic curve of the main reflector in the horizontal plane.
a primary radiator for generating a rotationally symmetrical beam;
a main reflector having a different aperture diameter in the vertical plane to that of the horizontal plane, and a subreflector having a curved surface to convert a spherical wave to a wave having a different curvature in the vertical plane to that of the horizontal plane to permit the beam to be effectively intercepted by the main reflector;
wherein the main reflector has parabolic curves having a different focus in the vertical plane to that of the horizontal plane, the subreflector has hyperbolic curves having focuses corresponding to a phase center of the primary radiator and to the focus of a vertical parabolic curve of the main reflector in the vertical plane, and the subreflector has hyperbolic curves having focuses corresponding to a phase center of the primary radiator and to the focus of a horizontal parabolic curve of the main reflector in the horizontal plane.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7874573A JPS5712323B2 (en) | 1973-07-12 | 1973-07-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1037155A true CA1037155A (en) | 1978-08-22 |
Family
ID=13670409
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA204,614A Expired CA1037155A (en) | 1973-07-12 | 1974-07-11 | Reflector antenna |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5712323B2 (en) |
| CA (1) | CA1037155A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH033504A (en) * | 1989-05-31 | 1991-01-09 | Nec Corp | Dual reflection mirror antenna |
-
1973
- 1973-07-12 JP JP7874573A patent/JPS5712323B2/ja not_active Expired
-
1974
- 1974-07-11 CA CA204,614A patent/CA1037155A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5712323B2 (en) | 1982-03-10 |
| JPS5028256A (en) | 1975-03-22 |
| AU7083674A (en) | 1976-01-08 |
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