FIELD OF THE INVENTION

The present invention generally relates to a material for potting and encapsulating electronic circuits and more particularly, relates to a potting material to reduce radio frequency signal attenuation in electronic devices.

BACKGROUND

Radio frequency (RF) devices are a type of electronic devices capable of transmitting and receiving a wireless or radio signal. RF devices can be based on technologies, such as RADAR, Global System for Mobile communication (GSM), Global Positioning System (GPS), and Bluetooth, which can transmit wireless signals. Such RF devices particularly include an RF circuitry having an antenna that transmits and receives the wireless signal of a predefined frequency.

It is well known that encapsulation resins and potting compounds are used to protect RF devices from chemicals, dust, heat, temperature fluctuation, water, dampness, corrosive atmospheres, physical shock, vibration, or just the general environment. Such resins offer excellent physical protection to electronic components and constituent electrical units. This level of protection enables the components and the electrical units to offer superior performance, particularly, when subjected to prolonged exposure or immersion in harsh chemicals, to vibrations, or to thermal or physical shock.

Among different resins, epoxy, polyurethane (PU), and silicone resins are extensively used in potting applications. Most of the commercially used epoxy resins are produced by the reaction of Bisphenol A and epichlorohydrin. The epoxy resin is used for excellent bond strength and adhesion to a variety of substrates. Owing to its excellent chemical, moisture, and temperature resistance, the epoxy resin provides excellent strength to components and electrical insulation, making them ideal for use in high-voltage applications.

However, PU resin is ideal for flexible applications with a broad range of hardness characteristics and operating temperatures (up to 130°C). PU resins are more flexible than epoxies and hence put less strain on potted components, especially, for thermal cycling and in low-temperature environments (down to -40?).

On the other hand, silicone resins offer excellent flexibility and operate over the widest temperature range (-65 to 315?). Its low reaction exotherm (low heat generation), low toxicity, low cure shrinkage, good electrical properties, excellent chemical, environmental, and UV light and ozone resistance makes them suitable for potting sensitive electronics.

Typically, an RF device encapsulated in resin includes an RF circuitry placed on a metal plate. The RF device is potted in a polymeric potted material. The polymeric potted material may be a compound including, but not limited to, silicone, polyurethane, and epoxy-based materials. However, the polymeric potting material suppresses or attenuates the RF signal strength of the RF device. Consequently, achieving RF signal strength in encapsulated electronics poses a critical challenge. One way to mitigate this issue is to increase the power of the RF device. However, such an increase causes additional power consumption. Moreover, additional consumption results in more heat generation which warrants a larger metal plate for heat dissipation, ultimately increasing the overall size of the RF device.

Thus, there lies an unaddressed need for encapsulating the RF device with potting material while preventing the attenuation of RF signals without compromising mechanical integrity.

SUMMARY

This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.

The present disclosure relates to a potting material for a Radio Frequency (RF) device. The potting material is adapted to reduce RF signal attenuation in the RF device. The potting material includes a resin material and at least one glass balloon disposed in the resin material. The resin material includes one of a silicone-based material, a polyurethane-based material, and an epoxy-based material.

In an embodiment, each of the glass balloons includes resins of low dielectric constant. In an embodiment, the size of each of the glass balloons ranges from 5 to 400 µm.

Another embodiment of the present disclosure relates to a method of preparing a potting material for reducing Radio Frequency (RF) signal attenuation in an RF device. The method includes mixing a hollow glass bead power having at least one glass balloon with a resin material to form a premix. The resin material includes at least one of a silicone-based material, a polyurethane-based material, and an epoxy-based material. The method also includes mixing the premix with a hardener material to prepare the potting material.

The glass balloons in the potting material provides the void space in cured potting materials leading to a reduction in an effective thickness of solid materials on top of the RF devices, say, RF transmitting devices. As a result, the attenuation of the signal is significantly minimized. On the other hand, the resin material provides the requisite strength to the RF device. In addition, substituting the resin material with glass balloons also reduces the volume of resin material needed to pot the RF device.

To further clarify the advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

Figure 1 illustrates a schematic diagram depicting a Radio Frequency (RF) device having a potting material deposited thereon leading to enhancement of RF signal range from the RF device, according to an embodiment of the present disclosure;

Figure 2 illustrates a Scanning Electron Microscope (SEM) micrograph depicting glass balloons of the potting material in varying sizes, according to an embodiment of the present disclosure; and

Figure 3 illustrates a method of preparing the potting material, according to an embodiment of the present disclosure.

Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the present invention. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

DETAILED DESCRIPTION OF FIGURES

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.

The term “some” as used herein is defined as “none, or one, or more than one, or all.” Accordingly, the terms “none,” “one,” “more than one,” “more than one, but not all” or “all” would all fall under the definition of “some.” The term “some embodiments” may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments. Accordingly, the term “some embodiments” is defined as meaning “no embodiment, or one embodiment, or more than one embodiment, or all embodiments.”

The terminology and structure employed herein is for describing, teaching and illuminating some embodiments and their specific features and elements and does not limit, restrict or reduce the spirit and scope of the claims or their equivalents.

More specifically, any terms used herein such as but not limited to “includes,” “comprises,” “has,” “consists,” and grammatical variants thereof do NOT specify an exact limitation or restriction and certainly do NOT exclude the possible addition of one or more features or elements, unless otherwise stated, and furthermore must NOT be taken to exclude the possible removal of one or more of the listed features and elements, unless otherwise stated with the limiting language “MUST comprise” or “NEEDS TO include.”

Whether or not a certain feature or element was limited to being used only once, either way, it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do NOT preclude there being none of that feature or element, unless otherwise specified by limiting language such as “there NEEDS to be one or more...” or “one or more element is REQUIRED.”

Unless otherwise defined, all terms, and especially any technical and/or scientific terms, used herein may be understood to have the same meaning as commonly understood by one having ordinary skills in the art.

Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the attached claims. Some embodiments have been described for the purpose of illuminating one or more of the potential ways in which the specific features and/or elements of the attached claims fulfil the requirements of uniqueness, utility and non-obviousness.

Use of the phrases and/or terms such as but not limited to “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or variants thereof do NOT necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or alternatively in the context of more than one embodiment, or further alternatively in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.

Any particular and all details set forth herein are used in the context of some embodiments and therefore should NOT be necessarily taken as limiting factors to the attached claims. The attached claims and their legal equivalents can be realized in the context of embodiments other than the ones used as illustrative examples in the description below.

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

Figure 1 illustrates a Radio frequency (RF) device 100 having a potting material 102 deposited thereon, according to an embodiment of the present disclosure. In an embodiment, the RF device 100 may be a transmitter operating based on Bluetooth, Global Positioning System (GPS), a Global System for Mobile communication (GSM), or a RADAR, and capable of transmitting radio waves of frequency ranging from 0.1 to 30 GHz.

In an embodiment, the RF device 100 may include an RF circuitry 102 and a base plate 101. The RF circuitry 102 is designed to transmit information by converting electronic signals into radio signals. The RF circuitry 102 may include a circuit adapted to process an input electronic signal and an antenna to transmit the processed electronic signal as radio signals. During the operation, the RF circuitry 102 transmits the radio signals while the base plate 101 dissipates the heat from the RF circuitry 102.

The RF device 100 may also include a potting material 103 deposited on top of the base plate 101, such that the potting material 103 covers both the base plate 101 and the RF circuitry 102. The potting material 103 of the present disclosure is adapted to perform various tasks. First, the potting material 103 is adapted to protect the base plate 101 and the RF circuitry 102, say, from the environment. Second, the potting material 103 allows transmission of the radio signal therethrough without attenuating the radio signals. The potting material 103 is able to reduce attenuation because of its composition.

In an embodiment, the potting material 103 may include a resin material that forms a base of the potting material 103. In an embodiment, the resin material may be a silicon-based material. In another embodiment, the resin material may be polyurethane-based material or epoxy-based material. In either embodiment, the resin material is configured to provide mechanical strength to the RF device 100. Further, the resin material is adapted to absorb the vibrations received by the RF device 100. In addition, the resin material also prevents dust and water from coming in contact with the RF circuitry 102, thereby sealing the assembly in effect.

Generally, during the potting operation, the potting resin 103 may introduce capacitance effects between conductors on a Printed Circuit Board (PCB) and unacceptably alter the characteristics of the circuit. Such an instance is avoided by the use of glass balloons 103a containing resins of low dielectric constant. The potting material 103 of the present disclosure may include the glass balloons 103a disposed in the resin material. The glass balloons 103a are spherical Micro-balloons glass structures in which a resin of low dielectric constant is filled.

Micro-balloons or micro-spheres are microscopic hollow spheres used as an additive to many materials to modify the characteristics. For instance, the glass balloons 103a are configured to prevent radio signal attenuation by not impeding the radio signal emitted by the RF circuitry 102 and as a result, the radio signals do not lose strength while being emitted from the RF device 100.

In an embodiment, the glass balloons 103a are disposed in the resin material in a range of 30 to 60 volume percentage. Higher concentrations are desirable to achieve better signal transmission but it may impact the potting materials characteristics, such as hardness, viscosity, mechanical strength, and moisture absorption. Hence, the concentration of the glass balloons 103a in the resin material should be such that it meets the signal strength requirement along with above-mentioned material characteristics.

In an embodiment, epoxy resin with 50 volume percentage of the glass balloons 103a improved almost 100% signal transmission along with following materials level properties. Another advantage of having this concentration is that the final potting material 103 is light in weight, say, about 10 to 50 % depending on the glass beads concentration.

Figure 2 illustrates a Scanning Electron Microscope (SEM) micrograph 200 depicting glass balloons 103a in varying sizes, according to an embodiment of the present disclosure. In an embodiment, the glass balloons 103a are sized between 5 to 400 µm to achieve better transparency for the radio signals. Further, the glass balloons 103a have a density that ranges from 0.2 to 0.5 gm/cm3, which is much lower than that of the resin material. As the density of glass balloons 103a (0.2 to 0.5 gm/cm3) is significantly lower than the resin, the density of cured resin significantly reduces depending on the volume percentage of the glass balloons 103a added in the polymeric resin. In addition, the glass balloons 103a may have a shell thickness that ranges between 2 µm to 30 µm. The proposed composition enables the glass balloons 103a to prevent signal attenuations.

The hollow spherically shaped gas balloons 103a have very distinctive properties, such as lightweight, good flowability, chemically inertness, good insulation, high compressive strength, and low thermal conductivity, thus making it one of the most important value-added materials for many industrial applications, especially in light-weight applications (lightweight cement, polymeric composites, automotive brake rotors and differential covers, mullite-coated diesel engine components, and electromagnetic shielding and energy absorption applications). Due to their spherical and hollow morphology, it has high resistance to crack propagation. In the various embodiments, the hollow glass beads having a density ranging from 0.2 to 0.5 gm/cm3 are used with particle size ranging from 5 µm to 400 µm in diameter and the shell thickness ranging from 2 µm to 30 µm. Based on the end application and property requirements, a resin system can be chosen to prepare a premix with glass balloons 103a.

In an embodiment, the potting material 103 includes a premix of the glass balloons 103a (for example, 10 to 70 volume percentage) mixed in the resin, for example, epoxy, polyurethane, or silicone, which is then mixed with the hardener before the potting. A varying amount of the glass balloons 103a is added to achieve the required range without compromising mechanical integrity. Therefore, the potting material 103 enhances the RF signal strength of the RF device 100.

Figure 3 illustrates a method 300 of preparing the potting material 103, according to an embodiment of the present disclosure. The order in which the method steps are described below is not intended to be construed as a limitation, and any number of the described method steps can be combined in any appropriate order to execute the method or an alternative method. Additionally, individual steps may be deleted from the method without departing from the spirit and scope of the subject matter described herein.

At a step 302, the method 300 includes mixing a hollow glass bead powder having the at least one glass balloon 103a with the resin material to form a premix. The power and the resin material may be mixed in an industrial mixture. The mixing is performed to achieve a homogenous dispersion of the glass balloons 103a inside the resin material. In one example, the amount of glass bead powder mixed in the resin material may be selected such that the glass balloon 103a is disposed in a range of 10 to 70 volume percentage. Further, the resin material is at least one of the silicone-based material, the polyurethane-based material, and the epoxy-based material.

Upon mixing, the method 300 proceeds to step 304 at which the premix is mixed with a hardener material to prepare the potting material 103. The hardener material may be understood as a material that cures the resin material. Further, as a part of mixing the hardener material with the premix, the mixture of the hardener material and the premix may be poured on the base plate 101 to cover both the base plate 101 and the RF circuitry 102 as the resin cures. The partially cured resin material may spread evenly over the base plate 101 and the RF circuitry 102.

As would be gathered, among other advantages as mentioned earlier, the glass balloon 103a with the resin of low dielectric constant in the potting material 103 allows unimpeded radio signal transmission while the resin material of the potting material 103 provides mechanical strength. The composition of the glass balloons 103a is selected to ensure effective transmission of the radio signals from the RF device 100. Moreover, the resin material enables pouring of the potting material 103 on the RF device 100 as easy as in the case of conventional potting operation, thereby eliminating the need for a specialised technique or equipment of applying the potting material 103 on the RF device 100. Hence, there is no need for an especially skilled labour for the application of the potting material 103 on the RF device 100. Consequently, the potting material 103 is cost-effective as well. Therefore, the potting material 103a of the present disclosure ensures effective transmission of the radio signals from the RF device 100 while also providing structural integrity to the RF device 100.

While specific language has been used to describe the present subject matter, any limitations arising on account thereto, are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein. The drawings and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment.

WE CLAIMS:

1. A potting material (103) for reducing Radio Frequency (RF) signal attenuation in an RF device (102), the potting material (103) comprising:
a resin material, wherein the resin material is one of a silicone-based material, a polyurethane-based material, and an epoxy-based material; and
at least one glass balloon (103a) disposed in the resin material.

2. The potting material (103) as claimed in claim 1, wherein the at least one glass balloon (103a) comprising resins of low dielectric constant.

3. The potting material (103) as claimed in claim 1, wherein the at least one glass balloon (103a) is disposed with the resin material in a range of 30 to 60 volume percentage.

4. The potting material (103) as claimed in claim 1, wherein a size of the at least one glass balloon (103a) is in a range of 5 to 400 µm.

5. The potting material (103) as claimed in claim 1, wherein density of the at least one glass balloon (103a) ranges between 0.2 to 0.5 gm/cm3.

6. The potting material (103) as claimed in claim 1, wherein a shell thickness of each of the at least one glass balloon (103a) ranges between 2 µm to 30 µm.

7. A method (300) of preparing a potting material (103) for reducing Radio Frequency (RF) signal attenuation in an RF device (102), the method (300) comprising:
mixing a hollow glass bead powder having at least one glass balloon (103a) with a resin material to form a premix, wherein the resin material is at least one of a silicone-based material, a polyurethane-based material, and an epoxy-based material; and
mixing the premix with a hardener material to prepare the potting material (103).

8. The method (300) as claimed in claim 7, wherein the at least one glass balloon (103a) is mixed with the resin material in a range of 30 to 60 volume percentage.

9. The method (300) as claimed in claim 7, wherein the at least one glass balloon (103a) comprising resins of low dielectric constant.

10. The method (300) as claimed in claim 7, wherein a size of the at least one glass balloon (103a) is in a range of 5 to 400 µm.