Transformers or inductors (“transductors”) and antennas manufactured from conductive loaded resin-based materials

A low cost moldable transformer or trans-inductor core, referred to in this description as a transductor. Elements of the transductor core are formed of a conductive loaded resin-based material. The conductive loaded resin-based material comprises micron conductor fibers, micron conductor powders, or in combination thereof homogenized within a base resin host wherein the ratio of the weight of the conductor fibers, conductor powders, or combination thereof to the weight of the base resin host can be between about 0.20 and 0.40. The micron conductive fibers or powders, can be of stainless steel, nickel, copper, silver, carbon, graphite, plated particles, plated fibers, or the like. Transductors can be formed using methods such as injection molding, over-molding, thermo-set, protrusion, extrusion, compression, or the like, in combination with a large number of production or wire wrapping techniques to achieve desired electrical characteristics. The elements and/or cores of the transductor can be virtually any shapes and sizes desired. Parts may also can be cut, stamped, milled or the like, from molded conductive loaded materials that are in sheet or other various forms. The conductive loaded resin-based material provides very efficient coupling and control of electromagnetic energy between a bobbin formed of the conductive loaded resin-based material and a coil of wire wound on the bobbin.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention relates to “transductors”, or transformer/inductor like devices, and/or antennas formed by the molding process of conductive loaded resin-based materials comprising micron conductive powders or micron conductive fibers or in combination thereof.

(2) Description of the Related Art

Transformer/inductor like devices are used alone or in conjunction with antennas to perform a multitude of functions in electronic circuitry, such as controlling currents within antennas or transceivers. These devices are important to the overall functionality of the electronics or the devices.

U.S. Pat. No. 5,771,027 to Marks et al. describes a composite antenna having a grid comprised of electrical conductors woven into the warp of a resin reinforced cloth forming one layer of a multi-layer laminate structure of an antenna.

U.S. Pat. No. 4,768,436 to Kanamori et al. describes a high voltage resistance wire formed of a conductive composite mixed with a polymer.

U.S. Pat. No. 5,654,881 to Albrecht et al. describes a single stage power converter. The converter uses a transinductor, a multiple winding inductive element, having a primary winding providing energy storing inductance.

U.S. Pat. No. 4,035,710 to Joyce describes a voltage regulator-converter/power converter, which uses a transinductor, a multiple winding inductive element.

U.S. patent application Ser. No. 10/780,214, filed on Feb. 17, 2004, entitled “LOW COST ANTENNA AND ELECTRO MAGNETIC (EMF) ABSORBTION IN ELECTRONIC CIRCUIT PACKAGES OR TRANSCIEVERS USING CONDUCTIVE LOADED RESIN-BASED MATERIALS) assigned to the same assignee describe low cost antennas and electromagnetic absorption structures using conductive loaded resin-based materials.

SUMMARY OF THE INVENTION

Transformer/inductor like devices are an essential part of electronic circuitry, such as electronic communication systems that contain wireless links. Lowering the cost and improving the manufacturing capabilities for these devices provides an important advantage for these systems. Low cost molded transductors offer significant advantages for these systems not only from a fabrication standpoint, but also characteristics related to 2D, 3D, 4D, and 5D electrical characteristics, which include the physical advantages that can be achieved by the molding process of the actual parts and the polymer physics within the conductive networks formed within the molded part.

Transformer/inductor like devices which have wire windings around a core of conductively loaded resin-based material, and which may also use the core(s) for a secondary winding, are of great usefulness in coupling and controlling energy, impedance, VSWR, resonance and frequency of oscillation in these types of systems. These devices will hereinafter be referred to as transductors. Antennas can frequently be coupled to these wire windings in applications such as communications and navigation, which require reliable sensitive antennas. Lowering the materials and/or fabrication costs combined with added performance for these transductors offer significant advantages for many system design applications utilizing antennas.

It is a principle objective of this invention to provide a low cost, high performance, and efficient molded core of conductively loaded resin-based material, which is then wire wound as an electrical energy transformer or trans-inductor, hereinafter referred to as a transductor. The core is fabricated from molded conductive loaded resin-based materials, comprising micron conductive fibers, micron conductive powders, or in combination thereof, that are homogenized within a base resin host in a molding process.

It is another principle objective of this invention to provide a method of fabricating a low cost, high performance, and efficient molded core of conductively loaded resin-based material, which is then wire wound as an electrical energy transformer or trans-inductor, herein be referred to as a transductor. The core is fabricated from molded conductive loaded resin-based materials comprising micron conductive fibers, micron conductive powders, or in combination thereof, that are homogenized within a base resin during the molding process.

These objectives are achieved by molding the transductor core elements from conductive loaded resin-based materials. These materials are resins loaded with conductive materials to provide a resin-based material, which is a conductor rather than an insulator. The resins provide the structural material which; when loaded with micron conductive powders, micron conductive fibers, or any combination thereof, become composites which are conductors rather than insulators. The orientation of micron conductive fibers, micron conductive powders or in combination thereof, homogenized within the base resin may be tightly controlled in the molding process. Various desired electrical and EMF characteristics may be achieved during the molding and mix process.

These materials can be molded into any number of desired shapes and sizes using methods such as injection molding, over-molding, thermo-set, protrusion, extrusion, compression, or the like, in combination with a large number of production or wire gauges, wrapping techniques and winding(s) to achieve desired electrical characteristics for a transductor. The conductive loaded resin-based material could also be a molded part, sheet, bar stock, or the like that may be cut, stamped, milled, laminated, vacuumed formed, or the like to provide the desired shape and size of this element or part. The characteristics of the elements depend on the composition of the conductive loaded resin-based materials, which can be adjusted and tightly controlled in achieving the desired characteristics of the molded material.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following embodiments are examples of antennas, ground planes, and transductors, fabricated using conductive loaded resin-based materials. In some of the examples the ground planes can be formed of either conductive loaded resin-based materials or in combination or unison with metals such as circuit boards or the like contained within the device as a counterpoise. The use of conductive loaded resin-based materials in the fabrication of antennas, ground planes, and transductor elements significantly lowers the cost of materials and manufacturing processes used and the ease of forming these materials into the desired shapes. These materials can be used to manufacture either receiving or transmitting antennas and any combination of antennas and/or transductors. The antennas, ground planes, and transductor elements can be formed in infinite shapes using conventional methods such as injection molding, over-molding, thermo-set, protrusion, extrusion, compression or the like, when manufactured with conductive loaded resin-based materials.

The conductive loaded resin-based materials when molded typically but not exclusively produce a desirable usable range of resistivity from less than 5 to greater than 25 ohms per square. The selected materials used to build the transductor elements are homogenized together using molding techniques and/or methods such as injection molding, over-molding, thermo-set, protrusion, extrusion, compression, or the like.

The conductive loaded resin-based materials comprise micron conductive powders, micron conductive fibers, or in any combination thereof. The materials are homogenized together within the resin, during-the molding process, yielding an easy to produce low cost, electrically conductive, close tolerance manufactured part or circuit. The micron conductive powders can be of carbons, graphite's, amines or the like, and/or of metal powders such as nickel, copper, silver, or plated or the like. The use of carbons or other forms of powders such as graphite(s) etc. can create additional low activity level electron exchange and, when used in combination with micron conductive fibers, a micron filler element within the micron conductive network of fiber(s) producing further electrical conductivity as well as acting as a lubricant for the molding equipment. The micron conductive fibers can be nickel plated carbon fiber, stainless steel fiber, copper fiber, silver fiber, or the like. The structural material can be any polymer base resin. While the resin selection(s) also plays a roll in dielectric, dielectric loss tangents, permeability and or other related electrical characteristics within the vast selection of base resins. Structural material(s) can be, here given as examples and not as an exhaustive list, polymer resins produced by GE PLASTICS, Pittsfield, Mass., a range of other resins produced by GE PLASTICS, Pittsfield, Mass., a range of other resins produced by other manufacturers, silicones produced by GE SILICONES, Waterford, N.Y., or other flexible resin-based compounds produced by other manufacturers.

The resin-based structural material loaded with micron conductive powders, micron conductive fibers, or in combination thereof can be molded, using very basic methods such as injection molding, overmolding, or extruding the material(s) to the desired shapes. The molded conductive loaded resin-based materials may also be stamped, cut or milled as desired to form the desired shape of the antenna elements or transductor cores. The composition and directionality of the loaded materials can affect the device characteristics and can be precisely controlled in and during the molding process. A resin based laminate could also be fabricated with random webbed micron stainless steel fibers or other conductive fibers, forming a cloth like material which, when properly designed in fiber content(s), orientation(s) and shape(s), can be achieved to realize a very high performance flexible cloth-like antenna. Such a cloth-like antenna could be embedded in a persons clothing as well as in any other materials such as rubber(s) or plastic(s). The random webbed conductive fiber can be laminated or the like to materials such as Teflon, Polyesters, or any resin-based flexible or solid material polymer. When using conductive fibers as a webbed conductor material as part of a laminate the fibers may have diameters of between about 3 and 12 microns, typically between about 8 and 12 microns or in the range of 10 microns with length(s) that can be seamless.

Refer now toFIGS. 1-10Bfor examples of antennas fabricated using conductive loaded resin-based materials. These antennas can be either receiving and/or transmitting antennas.FIG. 1shows a perspective drawing of a dipole antenna with a radiating and/or receiving antenna element12and a counterpoise antenna element10formed from conductive loaded resin-based materials. The antenna comprises a radiating and/or receiving antenna element12and a counterpoise antenna element10each having a length24and a rectangular cross section perpendicular to the length24. The length24is greater than three multiplied by the square root of the cross sectional area. The center conductor14of a coaxial cable50is electrically connected to the radiating and/or receiving antenna element12using a solderable metal insert15formed in the radiating and/or receiving antenna element12. The shield52of the coaxial cable50is connected to the counterpoise antenna element10using a solderable metal insert formed or insert molded in the counterpoise antenna element10. The metal insert in the counterpoise antenna element10is not visible inFIG. 1but is the same as the metal insert15in the radiating and/or receiving antenna element12. The length24is a multiple of a quarter wavelength of the optimum frequency of detection or transmission of the antenna. The impedance of the antenna at resonance should be very nearly equal to the impedance of the coaxial cable50to assure maximum power transfer between cable and antenna.

FIG. 3shows a detailed view of a metal insert15formed in a segment11of an antenna element. The metal insert can be copper or other metal(s). A screw17can be used in the metal insert15to aid in electrical connections. Soldering or many other electrical connection methods can also be used.

FIG. 1shows an example of a dipole antenna with the radiating and/or receiving antenna element12placed on a layer of insulating material22, which is placed on a ground plane20, and the counterpoise antenna element10placed directly on the ground plane20. The ground plane20is optional and if the ground plane is not used the layer of insulating material22may not be necessary. As another option the counterpoise antenna element10can also be placed on a layer of insulating material22, see FIG.2A. If the ground plane20is used it can also be formed of the conductive loaded resin-based materials.

FIG. 2Ashows a front view of the dipole antenna ofFIG. 1for the example of an antenna using a ground plane20, a layer of insulating material22between the radiating and/or receiving antenna element12and the ground plane20, and the counterpoise antenna element10placed directly on the ground plane20.FIG. 2Bshows a front view of the dipole antenna ofFIG. 1for the example of an antenna using a ground plane20and a layer of insulating material22between both the radiating and/or receiving antenna element12and the counterpoise antenna element10.

As shown inFIG. 2C, an amplifier72can be inserted between the center conductor14of the coaxial cable and the radiating and/or receiving antenna element12. A wire70connects metal insert15in the radiating and/or receiving antenna element12to the amplifier72. For receiving antennas the input of the amplifier72is connected to the receiving antenna element12and the output of the amplifier72is connected to the center conductor14of the coaxial cable50. For transmitting antennas the output of the amplifier72is connected to the radiating antenna element12and the input of the amplifier72is connected to the center conductor14of the coaxial cable50.

In one example of this antenna the length24is about 1.5 inches with a square cross section of about 0.09 square inches. This antenna had a center frequency of about 900 MHz.

FIGS. 4A and 4Bshow perspective views of a patch antenna with a radiating and/or receiving antenna element40and a ground plane42formed from conductive loaded resin-based materials. The antenna comprises a radiating and/or receiving antenna element40and a ground plane42each having the shape of a rectangular plate with a thickness44and a separation between the plates46provided by insulating standoffs60. The square root of the area of the rectangular square plate forming the radiating and/or receiving antenna element40is greater than three multiplied by the thickness44. In one example of this antenna wherein the rectangular plate is a square with sides of 1.4 inches and a thickness of 0.41 inches the patch antenna provided good performance at a Global Position System, GPS, frequency of 1,575.42 MHz.

FIG. 4Ashows an example of the patch antenna where the coaxial cable50enters through the ground plane42. The coaxial cable shield52is connected to the ground plane42by means of a metal insert15in the ground plane. The coaxial cable center conductor14is connected to the radiating and/or receiving antenna element40by means of a metal insert15in the radiating and/or receiving antenna element40.FIG. 4Bshows an example of the patch antenna where the coaxial cable50enters between the radiating and/or receiving antenna element40and the ground plane42. The coaxial cable shield52is connected to the ground plane42by means of a metal insert15in the ground plane42. The coaxial cable center conductor14is connected to the radiating and/or receiving antenna element40by means of a metal insert15in the radiating and/or receiving antenna element40.

As shown inFIG. 5an amplifier72can be inserted between the coaxial cable center conductor14and the radiating and/or receiving antenna element40. A wire70connects the amplifier72to the metal insert15in the radiating and/or receiving antenna element40. For receiving antennas the input of the amplifier72is connected to the receiving antenna element40and the output of the amplifier72is connected to the center conductor14of the coaxial cable50. For transmitting antennas the output of the amplifier72is connected to the radiating antenna element40and the input of the amplifier72is connected to the center conductor14of the coaxial cable50.

FIG. 6shows an example of a monopole antenna having a radiating and/or receiving antenna element64, having a height71, arranged perpendicular to a ground plane68. The radiating and/or receiving antenna element64and the ground plane68are formed of conductive loaded resin-based materials. A layer of insulating material66separates the radiating and/or receiving antenna element64from the ground plane68. The height71of the radiating and/or receiving antenna element64is greater than three times the square root of the cross sectional area of the radiating and/or receiving antenna element64. An example of this antenna with a height71of 1.17 inches performed and matched well at a GPS frequency of 1,575.42 MHz.

FIG. 7shows an example of the monopole antenna described above with an amplifier72inserted between the center conductor14of the coaxial cable50and the radiating and/or receiving antenna element64. For receiving antennas the input of the amplifier72is connected to the receiving antenna element64and the output of the amplifier72is connected to the center conductor14of the coaxial cable50. For transmitting antennas the output of the amplifier72is connected to the radiating antenna element64and the input of the amplifier72is connected to the center conductor14of the coaxial cable50.

FIGS. 8A,8B, and8C shows an example of an L shaped antenna having a radiating and/or receiving antenna element80over a ground plane98. The radiating and/or receiving antenna element80and the ground plane98are formed of conductive loaded resin-based materials. A layer of insulating material96separates the radiating and/or receiving antenna element64from the ground plane98. The radiating and/or receiving antenna element80is made up of a first leg82and a second leg84.FIG. 8Ashows a top view of the antenna.FIG. 8Bshows a cross section of the first leg82. FIG.8C shows a cross section of the second leg84.FIGS. 8B and 8Cshow the ground plane98and the layer of insulating material96. The cross sectional area of the first leg82and the second leg84need not be the same. Antennas of this type may be typically built using overmolding technique(s) to join the conductive resin-based material to the insulating material.

Antennas of this type have a number of uses.FIGS. 9A and 9Bshow a dipole antenna, formed of conductive loaded resin-based materials, molded within an automobile bumper100, formed of insulating material. The dipole antenna has a radiating and/or receiving antenna element102and a counterpoise antenna element104.FIG. 9Ashows the top view of the bumper100with the molded antenna.FIG. 9Bshows the front view of the bumper100with the molded antenna.

Antennas of this type can be used for a number of additional applications and can be molded within, over-molded, or the like within the molding of a window of a vehicle, such as an automobile or an airplane.FIG. 10Ashows a schematic view of such a window106. The antenna110can be molded within the molding108. Antennas of this type can be molded or over-molded within in a plastic or resin based housing, or be part of the plastic or resin based shell itself, of portable or stationary electronic devices such as cellular phones, personal computers, or the like.FIG. 10Bshows a schematic view of a segment112of such a plastic or resin based housing with the antenna110molded, over-molded, inserted or the like in the housing112.

The conductive loaded resin-based material typically comprises a powder of conductor particles, fibers of a conductor material, or a combination thereof in a base resin host.FIG. 11shows cross section view of an example of conductor loaded resin-based material212having powder of conductor particles202in a base resin host204.FIG. 12Ashows a cross section view of an example of conductor loaded resin-based material212having conductor fibers210in a base resin host204.FIG. 12Bshows a cross section view of an example of conductor loaded resin-based material212having a powder of conductor particles202and conductor fibers210in a base resin host204. In these examples the diameters200of the conductor particles202in the powder are between about 3 and 12 microns. In these examples the conductor fibers210have diameters of between about 3 and 12 microns, typically in the range of 10 microns or between about 8 and 12 microns, and lengths of between about 2 and 14 millimeters. The conductors used for these conductor particles202or conductor fibers210can be stainless steel, nickel, copper, silver, graphite, plated particles, plated fibers, or other suitable metals or resin. These conductor particles or fibers are homogenized within a base resin. As previously mentioned, the conductive loaded resin-based materials have a resistivity between about less than 5 and up to greater than 25 ohms per square. To realize this resistivity the ratio of the weight of the conductor material, in this example the conductor particles202or conductor fibers210, to the weight of the base resin host204is between about 0.20 and 0.40. Stainless steel fiber of 8-11 micron in diameter with lengths of 4-6 millimeters with a fiber weight to base resin weight ratio of 0.30 will produce a very highly conductive material efficient within any EMF spectrum.

Transductor elements formed from conductive loaded resin-based materials can be molded in a number of different ways including injection molding, extrusion, or chemically induced molding techniques.FIG. 13shows a simplified schematic diagram of an injection mold showing a lower portion230and upper portion231of the mold. Blended conductive loaded resin-based material is injected into the mold cavity237through an injection opening235and cured thermally or chemically, producing a conductive loaded resin-based material of which the conductor material(s) are homogenized within the base resin. The upper portion231and lower portion230of the mold are then separated and the formed conductive transductor or antenna element is removed.

FIG. 14shows a simplified schematic diagram of an extruder for forming antenna or transductor elements using extrusion. Raw material(s) conductive loaded resin-based material is placed in the hopper239of the extrusion unit234. A piston, screw, press, or other means236is then used to force the thermally molten or a chemically induced curing conductive loaded resin-based material through an extrusion opening240which shapes the thermally molten or chemically induced cured conductive loaded resin-based material to the desired shape. The conductive loaded resin-based material is then fully cured by chemical reaction or thermal reaction to a hardened or pliable state and is ready to be handled and for use.

Referring now toFIGS. 15A and 15B, a preferred composition of the conductive loaded, resin-based material is illustrated. The conductive loaded resin based material can be formed into fibers or textiles that are then woven or webbed into a conductive fabric. The conductive loaded resin-based material is formed in strands that can be woven as shown.FIG. 15Ashows a conductive fabric230where the fibers are woven together in a two-dimensional weave of fibers.FIG. 15Bshows a conductive fabric232where the fibers are formed in a webbed arrangement. In the webbed arrangement, one or more continuous strands of the conductive fiber are nested in a random fashion within the resin. The resulting conductive fabrics230, seeFIG. 15A, and232, seeFIG. 15B, can be made very thin.

Similarly, a family of polyesters or the like can be formed using woven or webbed micron stainless steel fibers, or other micron conductive fibers, to create a metallic, but cloth-like, material. These woven or webbed conductive cloths could also be laminated to one or more layers of materials such as polyester(s), Teflon, or other resin-based material(s). This conductive fabric may then be cut into desired shapes.

Refer now toFIGS. 16-18for a description of an embodiment of the electromagnetic energy transfer device of this invention, a transformer or trans-inductor, which will be referred to in this description as a transductor.FIG. 16shows a perspective view of a transductor showing a formed bobbin304, having a first end303and a second end305, supported by a first conductive support member300and a second conductive support member302.FIG. 17shows a cross section view of the transductor taken along line17-17′ of FIG.16.FIG. 18shows a cross section view of the formed bobbin304taken along line18-18′ of FIG.16. As shown inFIGS. 16 and 17the first end303of the bobbin304is attached to the first support member300and the second end305of the bobbin304is attached to the second support member302. The bobbin304, the first support member300, and the second support member302are formed of conductive loaded resin-based material previously described. As can be seen inFIG. 18the bobbin304in this example has a rectangular cross section; although other cross section shapes, such as a circular cross section, an oval cross section, or the like could be used in place of the rectangular cross section. As can be seen inFIG. 16the first support member300and the second support member302in this example have rectangular cross sections; although other cross section shapes, such as a circular cross section, an oval cross section, or the like could be used in place of the rectangular cross section.

As shown inFIGS. 16-18the an number of turns of insulated wire306, having a first end309and a second end311, are wound around the bobbin304with overlapping windings. As shown inFIG. 16the first end309and the second end311of the turns of insulated wire306are connected to electronic circuitry310which can serve as either a source, sink or current control for electromagnetic energy. Electromagnetic energy is coupled between current in the windings306and the bobbin304formed of conductive loaded resin-based material. The bobbin304is connected to the first support member300and second support member302which also are formed of conductive loaded resin-based material. Typically the first support member300and the second support member302are connected to an antenna312, such as one of the antennas previously described. In the case of a transmitting antenna the electronic circuitry310serves as a source of electromagnetic energy which is delivered to the turns of wire306, coupled onto the bobbin304, and delivered to the antenna312by the first300and second302support members. In the case of a receiving antenna the antenna312serves as a source of electromagnetic energy which is delivered to the bobbin and coil304by the first300and second302support members, coupled into the turns of wire306, and delivered to the electronic circuitry310.

The bobbin304, first support member300, and second support member are formed of the conductive loaded resin-based material and can be formed by injection, compression, thermal molding, or the like, seeFIGS. 13 and 14. The bobbin304, first support member300, and second support member, formed of the conductive loaded resin-based material, provides very efficient coupling to the turns of wire306, is inexpensive, light, and can be shaped in any dimensional form.

The transfer of electromagnetic energy between the wire306and the bobbin304is very efficient and is typically designed to be of a limited bandwidth. The dimensions of the bobbin304, the dimensions of the first300and second302support elements, the length of the wire in the winding306, the thickness of the wire in the winding306, and wiring density of the winding306are adjusted to determine center frequency of maximum coupling between the wire306and the bobbin300. The center frequency of some applications has been designed to be between about 137 and 152 Megahertz. Center frequencies of between about 2 kilohertz and 300 gigahertz or almost any other desired frequency can be achieved.