CA1226362A - Manufacture of parabola antennas - Google Patents
Manufacture of parabola antennasInfo
- Publication number
- CA1226362A CA1226362A CA000463639A CA463639A CA1226362A CA 1226362 A CA1226362 A CA 1226362A CA 000463639 A CA000463639 A CA 000463639A CA 463639 A CA463639 A CA 463639A CA 1226362 A CA1226362 A CA 1226362A
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- CA
- Canada
- Prior art keywords
- layer
- resin
- reflective
- layering
- thermosetting
- Prior art date
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- Expired
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Abstract
MANUFACTURE OF PARABOLA ANTENNAS
Abstract of Disclosure Plastic-made parabola antennas are improved to get more wave gain in the process of manufacture thereof where a wave reflector material is embedded in other molding materials so as not to cause dislocation thereof during thermoset-molding.
Abstract of Disclosure Plastic-made parabola antennas are improved to get more wave gain in the process of manufacture thereof where a wave reflector material is embedded in other molding materials so as not to cause dislocation thereof during thermoset-molding.
Description
fi3~i~
MANUFACTURE OF PAR`ABOLA ANTENNAS
This invention relates to a parabola antenna made of reinforced plastic and production of the same It has been proposed to manufacture parabola antennas with reinforced plastics for their primary merits ox superior resistance to corrosion and light weight, replaclng conventional metal-made antennas which are manufactured by press and other metal processings with use of aluminum, steel or other metals. Manufacture of antennas wit reinforced plastics involves processings where a materiaL for an electric conductive reflector (hereinafter abbreviated as reflector), such as metal net, carbonfiber mat, is piled in other reinforcing and/or resineous materials, and is molded into an intended parabola appearance as a whole. however, undesirable problems involved therein are such -that the reflector is hardly remained or positioned at predetermined points adequate to define an exact geometrical parabola, because of uneven internal pressures occurring in the moldlng proces-s in a mold. ~ur-ther partial breaks of the reflector material are liable to take place. In principle, a reflector is embedded or enclosed in reinforcing resineous materials and hardened during the manufacture where a built-in reflector should take an exact parabolic figure to achieve superior focussing of waves toward the focus point of the antenna surface. Therefore, dislocation 3~
thereof from predetermined positions in a molci during the hardening of resinous materials including the reflector or possiole oreaks due to extreme uneven molding pressure should De prevented. Further re-adjustment of reflector position after molding is almost impossiole to oe effected, therefor it is an important task to develop a technique for molding without fear of dislocation much less oreaking of the reflector surface.
Figure 1 is a sectional view of a tease part of a mold in the act of molding a para~olir antenna; and Figure 2 is a perspective view of a typical paraoolic antenna.
Making re ference generally to molding of a parat~olic antenna Dy the beforementioned process in more detail with reference to drawings which will ye explained hereinafter and which are attached herewith; F igure 1 shows a couple o-f male molds, a Female mold and laminated rnolding materials where the numeral 1 denotes the male one to oe positioned at the side of concave surface or front surface of the paraoolic antenna and 2 denotes the female one to oe oppositely positioned at the side of convex surface or rear surface of the parabolic antenna. In operation, manual works include application of a mold releaser on two coupling molds and mal<ing of gel coats as denoted oy la and 2a. Thereafter a reflector material and other resinous rnaterials are laminated or piled, conventionally without special precautions.
However, this invention employa the technique that a reflector materialmay not oe piled in the middle portion of the molding pile, instead, this invention intends to place the reflector so as to t)e close to the concave surface side which is close to the surface of the male mold in the drawing.
In more embodied procedures to effect the present invention, a male side buffer material 3a i.s piled to laminate on the gel coat la, thereon the reflector material 4 and the female-side buffer material 3b are piled or laminated, thereto thermosetting liquid resins are applied to impregnate into the above said piled materials. Further thereon so called sheet molding compound (SMC), known to those in the art, or other molding compounds are additionally piled to the predetermined height which will be noted as support portions hereinlater~ when the coupling molds are closed to heat and to thermoset the whole molding compound.
When hand-layup method or sprayup method, known to those in the art, is employed with use of only the male mold 1, a buffer material 3b to be placed at the side o:E the convex surface may be omitted.
One of features of the invention resides in the application of buffer sheet material in touch with the reflector material.
A reflector material noted above may be a metal net made of aluminum, steel or brass; cloth or mat made of carbonfiber; further a metallic bulk material comprising metal-coated glassfiber chops and/or carbonblack as electric conductive filler.
A buffer material in this invention may -- 3 -- .
36;~
preferably be a cloth or mat made of glass fiber or cellulosic, or other organic fibers where unitage weight or weight per uni-t area -thereof is preferably in the range of lO
to 100 g/m2. Above 100 g/m2 or below lO g/m2 buffer effects obtained become insufficient or scarce.
As noted hereinbefore, sheet molding compounds (SMC) may be used which are known as molding materials derived from liquid thermosetting resin and glass fiber staple or mat, and likewise resin-impregnated or-prepregnated mats or cloths may be used which are known as molding materials prepared by impregnation of liquid resins or by the step of impregnation into fiber substrates followed by gelation.
Molding materials as mentioned above are referred to S. Oleesky and G. Mohr "Handbook of Reinforced Plastics of SPI", Reinhold Publishing, 1964.
This invention covers another aspect where a reflector material or a buffer material is impregnated or prepregnated prior to application or to lamination to molding in oder that ease of internal friction or enhance of compatibility among molding materials may be farther obtained in the molding process.
A liquid thermosetting resin to be used to the above impregnation and prepregnation is preEerably . _ 3~
selected from those which are equal or compatible to other molding materials. Examples thereof are; unsaturated polyester, epoxy, melamine, phenol and diallyl phthalate resins Manners of the resin treatments noted above are known. Namely, prepregnation is effected by keeping impregnated cloths or mats under a suitable (temperature x (time) condition, for instance, (40C - 80C) x (1 - 7 hrs).
An amount of prepregnated or impregnated resin is preferred to be 5 to 9S by resin pick up weight.
This invention is explained heretofore based on thermosetting type reinforcing resins, but support portions in the sectional view as denoted by 5 in the drawing may consist of a thermoplastic resin, in place of thermosetting. Suitable thermoplastic resins are, for instance, polyamide polyethyleneterephthalate, poly-propylene which will be molded by means of injection mold-ing technique.
Making brief explanation of Drawings, Fig. 1 shows a sectional view of base part of a mold in the act of molding a parabola antenna wherein 1 denotes a male mold to define the concave surface or front surface of the antenna and 2 denotes a female mold to define the convex surface or rear surface of the antenna. la and 2a are gel coats. 4 is an electric conductive reflector material made of t for instance, carbonfiber mat. 3a and 3b are sheet-form buffer materials which are placed to laminate on the reflector material 4 respectively.
~63~2 5 is the suppor-t portion. It is to be noted that Fig. 1 is drawn with curvature to advantage. Fig. 2 shows a perspective view of a typical parabola antenna. The mark (A) indicates the concave or front surface and (B) does the convex or rear surface of the antenna.
Example 1 A male mold having a parabolic shape was treated with a mold releaser and a gel coat was made with unsaturated polyester thereon. Further a glass fiber cloth having a unltage weight oflO0 g/m2 as buffer and an aluminum net having 16 mesh openings (0.2 mm wire diameter) as reflector were piled ln sequence. Then unsaturated polyester was applied to impregnate the pile. Thereafter a superstructure as support portion was built up by known hand layup method.
Namely, glass fiber-choped stranded mats and roving cloths were piled in order while catalyst-incorporated unsaturated polyester liquid was applied thereto and puttied with roller and brush until the intended thickness of 4.5 to 5 mm was obtained. After hardening, a parabola antenna having 1,8 m in diameter was demolded and finished.
Example 2 : A couple of molds, male and female, were relese-treated. Several SMC materials were piled in the~female mold to have an intended thickness of 3 to 3.5 mm, thereon the first buffer, glassfiber mat having 30 g/m2, a carbonfiber mat having 30 g/m2 as reElector and the second glassfiber mat having the same weigh-t were piled i2 in sequence. Thereaf-ter the male mold was covered thereon to close and thermosetting was effected with 140C under 80 kg/cm2 in pressure for 4 minutes, by which a parabola antenna having 1.0 m in diameter was molded.
Example 3 An aluminum net having 16 mesh was used as reflector material in place as noted in Example 2. The same operations were otherwise conducted and another antenna containing aluminum reflector was manufactured.
Example 4 In a male-female mold, glass fiber cloth as buffer and carbonfiber mat as reflector were piled. Into -the closed mold, molton polypropylene was injected to make the support portion. A parabola antenna having 1 m in diameter was obtained.
Comparative Examples 1 - 4 In the above four (4) examples, buffer mats or cloths were omitted from molding preparations respectively.
Antennas thus obtained are listed as Comparative 1 - 4 below.
Parabola antennas obtained in the above examples and comparative ones were mounted with requisite trimming devices, such as, a horn, a waveguide and a converter.
Wave receiving tests were conducted to measure wave gains of respective antennas under conditions that the distance 3~;~
from transmitting point was set 200 m for 1.8 m antennas and 1000 m for 1.0 m antennas. Results are shown in Table 1.
Table 1 antenna wave galn reflector buffer diameter (GHZ) ~dB) _ __ _ Example 1 A1 net glass cloth 35.0 . 1 1.8 4 Comparative A1 net none 33.5 Example 2 CF mat glass mat 40.2 _ _ I 1.0 12 _ Comparative CF mat none 38.5 _ _ _ _ __ .
example 3 Al net glass mat 40.4 1.0 12 Comparative Al net none 38.6 _ Example 4 CF matglass clo-th 39.8 . 1.0 12 Comparative _ CF mat none _ 38.0 Results in Table 1 prove that provision of the buffer material beside the reflector material exerts to suprior performance of resultant antenna over difference in process of manufacture and in sort of reflector material.
Example 5 A carbonfiber mat having 30 g/m2 was dipped in ~63~;~
unsaturated polyester liquld end squeezed by a roller to remove an excess liquid resin. Then the mat was prepregnated in an oven at 60C while the mat was put for 3 hrs on a curved prototype mold so as to take on the mold curveture.
The amount of resin pick-up was 50 weight %~
The mold--shaped prepregnated mat was placed on a male mold and thereon a subsequent superstructure was laminated by sprayup method with glassfiber mat and unsaturated polyester up to 3 mm -thickness. Then a parabola antenna having 1.0 m in diameter was manufactured by routine procedures.
Example The prepregnated carbonfiber mat as prepared in Example 5 was included in other SMC molding materials and a parabola antenna having 1.0 m in diameter was manufactured.
E _ ple 7 The prepregnation liquid as used in Example 5 was replaced from unsaturated polyester to melamine resin.
Manufacturing operations were otherwise conducted in the same manner and the same sized parabola antenna was obtained, Example 3 The carbonfiber mat as used in Example 5 was replaced by brass net having 50 mesh (0.12 mm wire diameter).
Manufacturing operations were otherwise conducted in the same manner and the same sized parabola antenna was _ g _ 36;~:
obtained.
Comparative Examples 5 - 8 -In the foregoing four (4) examples, buffer mats were omi-tted from molding preparations respectively.
Antennas thus obtained are listed as Comparative 5 - 8 below.
Parabola antennas obtained in the examples 5 - 8 and comparative ones 5 - 8 were mounted with requisite trimming devices in the same manner as hereinbefore.
Wave receiving tests were conducted to measure wave gains of respective antennas under conditions that the distance is 1000 m and wave is 12 GHZ.
Table 2 I_ reflector prepregna- molding wave gain tion resin - _ _ _ .
Example 5 Carbon mat unsaturated spray up 39.4 polyester Compara. S 37.5 _ .
Example 6 carbon mat melamine sheet 40.0 _ . _ Example 7 carbon mat unsat. spray up 39.5 polyester . . .
Example 8 brass net unsaturated spray up 39.5 _ polyester _ Compara. 8 _ _ _ _ 37.7 I_ ___ ~2~;3~
Results in Table 2 prove that the same advantage was attained as shown in Table 1.
Example 9 A gla.ssfiber mat having 30 g/m2 unitage weight was dipped to impregnation with unsaturated polyester liquid which had been beforehand prepared to have a desired color. Then an excess liquid resin was removed by a roller and the impregnated glassfiber mat was put for prepregnation in an oven (60C) for 8 hrs.
while -the glassfiber mat was placed on a curved mold so as to take on the mold curveture. The amount of resin pick-up was 50 weight %.
On a mold for SMC molding use, the above-prepared prepregnated mat as the first buffer, carbonfiber mat (not impregnated or prepregnated) having 30 g/m2 as reflector and the same prepregnated mat as before as the second buffer were piled in sequence. Then the mold was closed and the whole molding materials were thermoset at 140C under 80 kg/cm2 for 4 minutes. Thus a parabola antenna having 1.0 m in diameter was manufactured. Wave receiving test thereof proved 40.0 dB gain.
Example 10 A glassfiber cloth having 100 g/m2 was prepregnated for use as buffer in the same manner as in the foregoing example. And a parabola antenna having 1.0 m in diameter was manufactured by routine SMC method. This antenna proved 39.9 dB gain.
36?~
Examp_e 11 A glassfiber ma-t having 30 g/m2 was subject to impregnation in the same manner as in example 9. An antenna was molded with use of the above prepreg-nated mat at the over-side of the reflec-tor in pile according to routine SMC method. A parabola antenna having 1.0 m in diameter thus manufactured proved ~0.0 dB gain.
Example l A glassfiber cloth was used to replace the mat in the foregoing. A parabola antenna having 1.0 m in diameter as manufactured in the same manner proved 39.9 dB gain.
MANUFACTURE OF PAR`ABOLA ANTENNAS
This invention relates to a parabola antenna made of reinforced plastic and production of the same It has been proposed to manufacture parabola antennas with reinforced plastics for their primary merits ox superior resistance to corrosion and light weight, replaclng conventional metal-made antennas which are manufactured by press and other metal processings with use of aluminum, steel or other metals. Manufacture of antennas wit reinforced plastics involves processings where a materiaL for an electric conductive reflector (hereinafter abbreviated as reflector), such as metal net, carbonfiber mat, is piled in other reinforcing and/or resineous materials, and is molded into an intended parabola appearance as a whole. however, undesirable problems involved therein are such -that the reflector is hardly remained or positioned at predetermined points adequate to define an exact geometrical parabola, because of uneven internal pressures occurring in the moldlng proces-s in a mold. ~ur-ther partial breaks of the reflector material are liable to take place. In principle, a reflector is embedded or enclosed in reinforcing resineous materials and hardened during the manufacture where a built-in reflector should take an exact parabolic figure to achieve superior focussing of waves toward the focus point of the antenna surface. Therefore, dislocation 3~
thereof from predetermined positions in a molci during the hardening of resinous materials including the reflector or possiole oreaks due to extreme uneven molding pressure should De prevented. Further re-adjustment of reflector position after molding is almost impossiole to oe effected, therefor it is an important task to develop a technique for molding without fear of dislocation much less oreaking of the reflector surface.
Figure 1 is a sectional view of a tease part of a mold in the act of molding a para~olir antenna; and Figure 2 is a perspective view of a typical paraoolic antenna.
Making re ference generally to molding of a parat~olic antenna Dy the beforementioned process in more detail with reference to drawings which will ye explained hereinafter and which are attached herewith; F igure 1 shows a couple o-f male molds, a Female mold and laminated rnolding materials where the numeral 1 denotes the male one to oe positioned at the side of concave surface or front surface of the paraoolic antenna and 2 denotes the female one to oe oppositely positioned at the side of convex surface or rear surface of the parabolic antenna. In operation, manual works include application of a mold releaser on two coupling molds and mal<ing of gel coats as denoted oy la and 2a. Thereafter a reflector material and other resinous rnaterials are laminated or piled, conventionally without special precautions.
However, this invention employa the technique that a reflector materialmay not oe piled in the middle portion of the molding pile, instead, this invention intends to place the reflector so as to t)e close to the concave surface side which is close to the surface of the male mold in the drawing.
In more embodied procedures to effect the present invention, a male side buffer material 3a i.s piled to laminate on the gel coat la, thereon the reflector material 4 and the female-side buffer material 3b are piled or laminated, thereto thermosetting liquid resins are applied to impregnate into the above said piled materials. Further thereon so called sheet molding compound (SMC), known to those in the art, or other molding compounds are additionally piled to the predetermined height which will be noted as support portions hereinlater~ when the coupling molds are closed to heat and to thermoset the whole molding compound.
When hand-layup method or sprayup method, known to those in the art, is employed with use of only the male mold 1, a buffer material 3b to be placed at the side o:E the convex surface may be omitted.
One of features of the invention resides in the application of buffer sheet material in touch with the reflector material.
A reflector material noted above may be a metal net made of aluminum, steel or brass; cloth or mat made of carbonfiber; further a metallic bulk material comprising metal-coated glassfiber chops and/or carbonblack as electric conductive filler.
A buffer material in this invention may -- 3 -- .
36;~
preferably be a cloth or mat made of glass fiber or cellulosic, or other organic fibers where unitage weight or weight per uni-t area -thereof is preferably in the range of lO
to 100 g/m2. Above 100 g/m2 or below lO g/m2 buffer effects obtained become insufficient or scarce.
As noted hereinbefore, sheet molding compounds (SMC) may be used which are known as molding materials derived from liquid thermosetting resin and glass fiber staple or mat, and likewise resin-impregnated or-prepregnated mats or cloths may be used which are known as molding materials prepared by impregnation of liquid resins or by the step of impregnation into fiber substrates followed by gelation.
Molding materials as mentioned above are referred to S. Oleesky and G. Mohr "Handbook of Reinforced Plastics of SPI", Reinhold Publishing, 1964.
This invention covers another aspect where a reflector material or a buffer material is impregnated or prepregnated prior to application or to lamination to molding in oder that ease of internal friction or enhance of compatibility among molding materials may be farther obtained in the molding process.
A liquid thermosetting resin to be used to the above impregnation and prepregnation is preEerably . _ 3~
selected from those which are equal or compatible to other molding materials. Examples thereof are; unsaturated polyester, epoxy, melamine, phenol and diallyl phthalate resins Manners of the resin treatments noted above are known. Namely, prepregnation is effected by keeping impregnated cloths or mats under a suitable (temperature x (time) condition, for instance, (40C - 80C) x (1 - 7 hrs).
An amount of prepregnated or impregnated resin is preferred to be 5 to 9S by resin pick up weight.
This invention is explained heretofore based on thermosetting type reinforcing resins, but support portions in the sectional view as denoted by 5 in the drawing may consist of a thermoplastic resin, in place of thermosetting. Suitable thermoplastic resins are, for instance, polyamide polyethyleneterephthalate, poly-propylene which will be molded by means of injection mold-ing technique.
Making brief explanation of Drawings, Fig. 1 shows a sectional view of base part of a mold in the act of molding a parabola antenna wherein 1 denotes a male mold to define the concave surface or front surface of the antenna and 2 denotes a female mold to define the convex surface or rear surface of the antenna. la and 2a are gel coats. 4 is an electric conductive reflector material made of t for instance, carbonfiber mat. 3a and 3b are sheet-form buffer materials which are placed to laminate on the reflector material 4 respectively.
~63~2 5 is the suppor-t portion. It is to be noted that Fig. 1 is drawn with curvature to advantage. Fig. 2 shows a perspective view of a typical parabola antenna. The mark (A) indicates the concave or front surface and (B) does the convex or rear surface of the antenna.
Example 1 A male mold having a parabolic shape was treated with a mold releaser and a gel coat was made with unsaturated polyester thereon. Further a glass fiber cloth having a unltage weight oflO0 g/m2 as buffer and an aluminum net having 16 mesh openings (0.2 mm wire diameter) as reflector were piled ln sequence. Then unsaturated polyester was applied to impregnate the pile. Thereafter a superstructure as support portion was built up by known hand layup method.
Namely, glass fiber-choped stranded mats and roving cloths were piled in order while catalyst-incorporated unsaturated polyester liquid was applied thereto and puttied with roller and brush until the intended thickness of 4.5 to 5 mm was obtained. After hardening, a parabola antenna having 1,8 m in diameter was demolded and finished.
Example 2 : A couple of molds, male and female, were relese-treated. Several SMC materials were piled in the~female mold to have an intended thickness of 3 to 3.5 mm, thereon the first buffer, glassfiber mat having 30 g/m2, a carbonfiber mat having 30 g/m2 as reElector and the second glassfiber mat having the same weigh-t were piled i2 in sequence. Thereaf-ter the male mold was covered thereon to close and thermosetting was effected with 140C under 80 kg/cm2 in pressure for 4 minutes, by which a parabola antenna having 1.0 m in diameter was molded.
Example 3 An aluminum net having 16 mesh was used as reflector material in place as noted in Example 2. The same operations were otherwise conducted and another antenna containing aluminum reflector was manufactured.
Example 4 In a male-female mold, glass fiber cloth as buffer and carbonfiber mat as reflector were piled. Into -the closed mold, molton polypropylene was injected to make the support portion. A parabola antenna having 1 m in diameter was obtained.
Comparative Examples 1 - 4 In the above four (4) examples, buffer mats or cloths were omitted from molding preparations respectively.
Antennas thus obtained are listed as Comparative 1 - 4 below.
Parabola antennas obtained in the above examples and comparative ones were mounted with requisite trimming devices, such as, a horn, a waveguide and a converter.
Wave receiving tests were conducted to measure wave gains of respective antennas under conditions that the distance 3~;~
from transmitting point was set 200 m for 1.8 m antennas and 1000 m for 1.0 m antennas. Results are shown in Table 1.
Table 1 antenna wave galn reflector buffer diameter (GHZ) ~dB) _ __ _ Example 1 A1 net glass cloth 35.0 . 1 1.8 4 Comparative A1 net none 33.5 Example 2 CF mat glass mat 40.2 _ _ I 1.0 12 _ Comparative CF mat none 38.5 _ _ _ _ __ .
example 3 Al net glass mat 40.4 1.0 12 Comparative Al net none 38.6 _ Example 4 CF matglass clo-th 39.8 . 1.0 12 Comparative _ CF mat none _ 38.0 Results in Table 1 prove that provision of the buffer material beside the reflector material exerts to suprior performance of resultant antenna over difference in process of manufacture and in sort of reflector material.
Example 5 A carbonfiber mat having 30 g/m2 was dipped in ~63~;~
unsaturated polyester liquld end squeezed by a roller to remove an excess liquid resin. Then the mat was prepregnated in an oven at 60C while the mat was put for 3 hrs on a curved prototype mold so as to take on the mold curveture.
The amount of resin pick-up was 50 weight %~
The mold--shaped prepregnated mat was placed on a male mold and thereon a subsequent superstructure was laminated by sprayup method with glassfiber mat and unsaturated polyester up to 3 mm -thickness. Then a parabola antenna having 1.0 m in diameter was manufactured by routine procedures.
Example The prepregnated carbonfiber mat as prepared in Example 5 was included in other SMC molding materials and a parabola antenna having 1.0 m in diameter was manufactured.
E _ ple 7 The prepregnation liquid as used in Example 5 was replaced from unsaturated polyester to melamine resin.
Manufacturing operations were otherwise conducted in the same manner and the same sized parabola antenna was obtained, Example 3 The carbonfiber mat as used in Example 5 was replaced by brass net having 50 mesh (0.12 mm wire diameter).
Manufacturing operations were otherwise conducted in the same manner and the same sized parabola antenna was _ g _ 36;~:
obtained.
Comparative Examples 5 - 8 -In the foregoing four (4) examples, buffer mats were omi-tted from molding preparations respectively.
Antennas thus obtained are listed as Comparative 5 - 8 below.
Parabola antennas obtained in the examples 5 - 8 and comparative ones 5 - 8 were mounted with requisite trimming devices in the same manner as hereinbefore.
Wave receiving tests were conducted to measure wave gains of respective antennas under conditions that the distance is 1000 m and wave is 12 GHZ.
Table 2 I_ reflector prepregna- molding wave gain tion resin - _ _ _ .
Example 5 Carbon mat unsaturated spray up 39.4 polyester Compara. S 37.5 _ .
Example 6 carbon mat melamine sheet 40.0 _ . _ Example 7 carbon mat unsat. spray up 39.5 polyester . . .
Example 8 brass net unsaturated spray up 39.5 _ polyester _ Compara. 8 _ _ _ _ 37.7 I_ ___ ~2~;3~
Results in Table 2 prove that the same advantage was attained as shown in Table 1.
Example 9 A gla.ssfiber mat having 30 g/m2 unitage weight was dipped to impregnation with unsaturated polyester liquid which had been beforehand prepared to have a desired color. Then an excess liquid resin was removed by a roller and the impregnated glassfiber mat was put for prepregnation in an oven (60C) for 8 hrs.
while -the glassfiber mat was placed on a curved mold so as to take on the mold curveture. The amount of resin pick-up was 50 weight %.
On a mold for SMC molding use, the above-prepared prepregnated mat as the first buffer, carbonfiber mat (not impregnated or prepregnated) having 30 g/m2 as reflector and the same prepregnated mat as before as the second buffer were piled in sequence. Then the mold was closed and the whole molding materials were thermoset at 140C under 80 kg/cm2 for 4 minutes. Thus a parabola antenna having 1.0 m in diameter was manufactured. Wave receiving test thereof proved 40.0 dB gain.
Example 10 A glassfiber cloth having 100 g/m2 was prepregnated for use as buffer in the same manner as in the foregoing example. And a parabola antenna having 1.0 m in diameter was manufactured by routine SMC method. This antenna proved 39.9 dB gain.
36?~
Examp_e 11 A glassfiber ma-t having 30 g/m2 was subject to impregnation in the same manner as in example 9. An antenna was molded with use of the above prepreg-nated mat at the over-side of the reflec-tor in pile according to routine SMC method. A parabola antenna having 1.0 m in diameter thus manufactured proved ~0.0 dB gain.
Example l A glassfiber cloth was used to replace the mat in the foregoing. A parabola antenna having 1.0 m in diameter as manufactured in the same manner proved 39.9 dB gain.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for manufacturing a plastic-made parabolic antenna including an electrically conductive reflector therein comprising the steps of:
applying to a male mold, shaped to form a parabolic interior surface of said antenna, a first thermosetting gel coat;
layering upon said first gel coat a reflective lamination layer made of metal-coated chopped glass fiber material impregnated prior to layering with a liquid thermosetting resin;
layering upon said reflective lamination layer a layer of thermosetting sheet molding material;
covering said mold with a mating female mold having a second thermosetting gel coat applied thereto; and heating said molds under pressure to thereby harden said thermosetting materials and laminate them together.
applying to a male mold, shaped to form a parabolic interior surface of said antenna, a first thermosetting gel coat;
layering upon said first gel coat a reflective lamination layer made of metal-coated chopped glass fiber material impregnated prior to layering with a liquid thermosetting resin;
layering upon said reflective lamination layer a layer of thermosetting sheet molding material;
covering said mold with a mating female mold having a second thermosetting gel coat applied thereto; and heating said molds under pressure to thereby harden said thermosetting materials and laminate them together.
2. A process claimed in Claim 1, comprising the further step of layering, in contact with said reflective lamination layer, a layer of buffer material impregnated with liquid thermosetting resin.
3. A process as claimed in Claim 1, comprising the further steps of layering, in contact with said reflective lamination layer at each side thereof, a layer of buffer material impregnated with liquid thermosetting resin.
4. The process according to Claims 2 or 3, wherein said buffer material is made of a material selected from the group consisting of glass fibers, cellulosic fibers and other organic fibers, and wherein the unit weight thereof is in the range of 10 to 100 grams per square meter.
5. The process according to any one of Claims 1, 2 or 3, where the liquid thermosetting resin is seected from the group consisting of unsaturated polyester resin, epoxy resin, melamine resin, phenol resin, and diallyl phthalate resin.
6. The process according to any one of Claims 1, 2 or 3, wherein said step of layering said reflective lamination layer further includes impregnating said layer with a liquid thermosetting resin selected from the group consisting of unsaturated polyester resin, epoxy resin, melamine resin, phenol resin, and diallyl phthalate resin, and molding it to a parabolic curvature.
7. A plastic-made parabolic antenna formed as a molded laminated article having a concave parabolic face surface, said article comprising a face surface layer of thermosetting gel, a reflective layer of metal-coated chopped glass fiber material embedded in a thermosetting resin, and a support portion, said reflective layer being formed closely adjacent said parabolic face surface.
8. A plastic-made parabolic antenna as claimed in Claim 7, further comprising a layer of buffer material laminated between said face surface layer and said reflective layer.
9. A plastic-made parabolic antenna as claimed in Claim 7, further comprising a layer of buffer material laminated between said reflective layer and said support portion.
10. A plastic-made parabolic antenna as claimed in Claim 7, further comprising layers of buffer material laminated between said reflective layer and both said face surface layer and said support portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000463639A CA1226362A (en) | 1984-09-19 | 1984-09-19 | Manufacture of parabola antennas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000463639A CA1226362A (en) | 1984-09-19 | 1984-09-19 | Manufacture of parabola antennas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1226362A true CA1226362A (en) | 1987-09-01 |
Family
ID=4128747
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000463639A Expired CA1226362A (en) | 1984-09-19 | 1984-09-19 | Manufacture of parabola antennas |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1226362A (en) |
-
1984
- 1984-09-19 CA CA000463639A patent/CA1226362A/en not_active Expired
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