1. A flexible microstrip patch antenna comprising: a radiating patch for transmission and reception of electromagnetic waves; a coplanar waveguide (CPW) fed structure connected to the radiating patch; and a flexible substrate composed of a nanocomposite material consisting of poly(vinylidene fluoride) (PVDF) and cobalt ferrite (CoFe₂O₄), wherein the cobalt ferrite nanoparticles are uniformly embedded in PVDF. wherein the overall antenna dimensions are approximately 20 mm × 20 mm in lateral size with a substrate thickness ranging from 70 μm to 100 μm.

2. The flexible microstrip patch antenna as claimed in claim 1, wherein the Flower-like cobalt ferrite nanospheres constitute 5% to 20% by weight of the PVDF-CFO composite, significantly improves the bandwidth, gain, crucial for efficient high-frequency antenna performance.

3. The flexible microstrip patch antenna as claimed in claim 1, wherein the antenna demonstrated an exceptional bandwidth of 12 GHz, covering Ku (12–18 GHz), K band (18–26.5 GHz), and Ka band (26.5–40 GHz).

4. The flexible microstrip patch antenna as claimed in claim 1, wherein a peak gain of up to 14 dB is achieved when the cobalt ferrite loading in the PVDF matrix is optimized to 20% by weight of the PVDF-CFO composite.

5. The flexible microstrip patch antenna as claimed in claim 1, wherein the PVDF/CoFe₂O₄ nanocomposite exhibits enhanced dielectric constant and magnetic permeability, contributing to improved antenna gain and bandwidth at microwave and millimetre-wave frequencies.

6. The flexible microstrip patch antenna as claimed in claim 1, wherein the antenna comprising a radiating element configured to operate at a frequency of 30 GHz, wherein the antenna exhibits a reflection loss of at least -27 dB at said frequency, and further wherein the antenna demonstrates a bidirectional radiation pattern.

7. The flexible microstrip patch antenna as claimed in claim 1, wherein the antenna is suitable for integration in high-frequency systems such as satellite communication, millimetre-wave radar, and radio frequency (RF) energy harvesting applications.

8. A solution cast method for fabricating the flexible microstrip patch antenna (using copper tape) as claimed in claim 1, wherein the method comprising the steps of: i. synthesizing cobalt ferrite nanospheres via hydrothermal technique; ii. dispersing the nanospheres into a PVDF solution under ultrasonic agitation; iii. casting the mixture onto a flat surface petri dish and drying to form a flexible nanocomposite film; and iv. depositing and patterning the radiating patch and CPW feed structure using copper tape photolithographic or additive manufacturing techniques.

Description:FIELD OF INVENTION
The present invention relates to flexible wireless antenna. More particularly, the present invention pertains to a microstrip antenna with coplanar waveguide fabricated on a substrate composed of a PVDF-CFO composite, enhancing the antenna’s mechanical flexibility, magnetic and dielectric performance and electromagnetic shielding for communication applications.

BACKGROUND OF THE INVENTION
The increasing demand for self-powered, portable, and flexible electronic devices has accelerated the development of advanced energy harvesting systems and compact communication modules. Among various energy sources, ambient radio frequency (RF) signals have emerged as a sustainable option for low-power devices through RF energy harvesting. However, the efficiency of such systems is heavily reliant on the performance of the antenna, which acts as the primary interface for capturing and transmitting energy.
Flexible antennas are becoming increasingly critical in modern wireless technologies such as wearables, internet of things (IoT), RFID and 5G devices. To enable miniaturized, lightweight, and flexible architectures, researchers have explored various antenna structures and materials. Microstrip patch antennas are particularly attractive due to their compact structure, low profile, ease of fabrication, and potential for integration into flexible platforms. The choice of substrate material is critical to antenna performance, especially for high-frequency applications.

US20060262030A1provides a layer-built antenna which adopts a substrate made of a composite containing magnetic material and polymer resin or a high magnetic permeability layer adjacent to a conductive antenna pattern in order to greatly shorten resonant length, thereby enabling size reduction even in a bandwidth of several hundred MHz. It further discloses that the magnetic material may comprise a magnetic oxide containing at least two elements selected from a group consisting of Fe, Ni, Co, Mn, Mg, Ba, Sr and Zn. The magnetic material may comprise at least one material selected from a group consisting of ferrite, magnetic metal and amorphous magnetic material.
CN102437420B relates to a three-frequency frequency reconfigurable antenna fed by a coplanar waveguide. It includes the metal microstrip on the upper layer, the dielectric substrate on the middle layer and the back floor on the lower layer. The metal microstrip includes a radiation patch, a coplanar waveguide floor, a coplanar waveguide feeder, a matching stub and 4 PIN diodes, and the coplanar waveguide floor surrounds the radiation patch. The coplanar waveguide floor and the radiation patch are connected by four PIN diodes. The coplanar waveguide feeder is located at the central opening under the coplanar waveguide floor and is integrated with the radiation patch. It can work in three wireless communication frequency bands of 0.9GHz, 1.8GHz, and 2.4GHz.
US20240021975A1 relates to a flexible wearable antenna intended for wireless communications applicable to medical telemetry. The antenna includes of radiating element fractal-based monopole antenna, made up of electrically mechanically connected fractal-based monopoles, connected to a modified coplanar waveguide transmission line with a conductor element connecting the coplanar waveguide ground planes and of the coplanar waveguide transmission line and a flexible substrate.
Kazmi, Syeda Javeria, et al. "PVDF/CFO-anchored CNTs ternary composite system with enhanced EMI shielding and EMW absorption properties." Journal of Alloys and Compounds 903 (2022): 163938.
Supriya, S., Kumar, L., & Kar, M. (2018). Optimization of dielectric properties of PVDF-CFO nanocomposites relates to incorporation of different types of nanofillers in the PVDF poly(vinylidene difluoride) matrix exhibits promising dielectric, magnetic, piezo, pyro, and ferroelectric properties for various applications. Hence a novel nanocomposite has been developed by using PVDF and cobalt ferrite (CFO) (CoFe2O4) with different particle size of CFO for dielectric applications. The space charge effect at the PVDF and CFO interfaces offers the interfacial polarization in nanocomposite, which contribute to tune the dielectric response of nanocomposite along with low dielectric loss. The filler size has been optimized to have better formation of polar β phase in PVDF along with high dielectric properties. The dielectric constant in nanocomposite has increased three times compare to that of PVDF.
PVDF is a promising polymer known for its excellent dielectric properties, mechanical flexibility, and ferroelectric behaviour. When combined with CFO, PVDF forms a multiferroic nanocomposite with enhanced dielectric and magnetic characteristics. Despite the potential advantages, the use of PVDF-CFO nanocomposites in antenna design remains unexplored, primarily due to fabrication complexities associated with ultra-thin, flexible films.
Therefore, the present invention addresses this gap by utilizing PVDF-CFO nanocomposites as the substrate in a compact, flexible microstrip patch antenna, offering enhanced performance for RF energy harvesting, radar, and high-frequency communication systems.

OBJECT OF THE INVENTION:
To address the foregoing problems, in whole or in part, and/or other problems that may have been observed by persons skilled in the art, the present disclosure provide a series of novel compounds as described by way of example as set forth below.

The principal object of the present invention is to provide a flexible microstrip antenna with coplanar waveguide fabricated on a PVDF-CFO composite substrate.
Another object of the present invention is to provide a flexible microstrip antenna that is suitable for high-frequency applications such as radar systems, satellite communications, and other advanced technologies.
Yet another object of the present invention is to provide a flexible microstrip antenna that is compact and ultra-thin, suitable for integration into portable and wearable high-frequency communication systems.
Yet another object of the present invention is to provide a mechanically flexible microstrip antenna that can be conformally mounted on curved surfaces such as wearables, textiles or biomedical patches.
Yet another object of the present invention is to fabricate a flexible microstrip antenna using PVDF-CFO nanocomposite substrate to improve the magnetic permeability and dielectric constant of the substrate for miniaturization and performance enhancement.
Yet another object of the present invention is to achieve wideband operation with low return loss through the use of coplanar waveguide feeding, suitable for multi-frequency applications.
Yet another object of the present invention is to improve electromagnetic interference (EMI) shielding and radiation efficiency, especially in compact or congested electronic environments.
Yet another object of the present invention is to design a substrate whose electromagnetic properties can be tuned by adjusting the concentration and distribution of cobalt ferrite nanoparticles.
Yet another object of the present invention is to provide an antenna system suitable for integration into next-generation devices, such as 5G modules, IoT sensors, smart clothing and implantation systems.
Yet another object of the present invention is to provide an antenna system ideal for integration into wearable antennas and flexible communication systems operating in Ku, K, and Ka bands.
Yet another object of the present invention is development of a functional antenna using highly flexible PVDF-CFO nanocomposites, especially in thin film form via solution casting method.

SUMMARY OF THE INVENTION
This summary is intended to introduce, in simplified form, a selection of concepts that are further described in the detailed description. This summary is merely presented as a brief overview of the subject matter described and claimed herein and does not aid in determining the scope of the claimed subject matter.

The present invention provides a flexible microstrip antenna with coplanar waveguide fabricated on a PVDF-CFO composite substrate.
In another aspect, the present invention provides a flexible microstrip patch antenna comprising:
a radiating patch for transmission and reception of electromagnetic waves;
a coplanar waveguide (CPW) fed structure connected to the radiating patch; and
a flexible substrate composed of a nanocomposite material consisting of poly(vinylidene fluoride) (PVDF) and cobalt ferrite (CoFe₂O₄), wherein the cobalt ferrite nanoparticles are uniformly embedded in PVDF.
wherein the overall antenna dimensions are approximately 20 mm × 20 mm in lateral size with a substrate thickness ranging from 70 μm to 100 μm.
In yet another aspect, the present invention provides a flexible microstrip patch antenna, wherein the Flower-like cobalt ferrite nanospheres constitute 5% to 20% by weight of the PVDF-CFO composite, significantly improves the bandwidth, gain, crucial for efficient high-frequency antenna performance.
In yet another aspect, the present invention provides a flexible microstrip patch antenna, wherein the antenna demonstrated an exceptional bandwidth of 12 GHz, covering Ku (12–18 GHz), K band (18–26.5 GHz), and Ka band (26.5–40 GHz).
In yet another aspect, the present invention provides a flexible microstrip patch antenna, wherein a peak gain of up to 14 dB is achieved when the cobalt ferrite loading in the PVDF matrix is optimized to 20% by weight of the PVDF-CFO composite.
In yet another aspect, the present invention provides a flexible microstrip patch antenna, wherein the PVDF/CoFe₂O₄ nanocomposite exhibits enhanced dielectric constant and magnetic permeability, contributing to improved antenna gain and bandwidth at microwave and millimetre-wave frequencies.
In yet another aspect, the present invention provides a flexible microstrip patch antenna, wherein the antenna comprising a radiating element configured to operate at a frequency of 30 GHz, wherein the antenna exhibits a reflection loss of at least -27 dB at said frequency, and further wherein the antenna demonstrates a bidirectional radiation pattern.
In yet another aspect, the present invention provides a flexible microstrip patch antenna, wherein the antenna is suitable for integration in high-frequency systems such as satellite communication, millimetre-wave radar, and radio frequency (RF) energy harvesting applications.
In yet another aspect, the PVDF-CFO nanocomposite-based substrate is fabricated using a solution casting method, resulting in a flexible, homogeneous, and defect-free film.
In yet another aspect, the present invention provides an easy solution cast method for fabricating the flexible microstrip patch antenna, wherein the method comprising the steps of:
i. synthesizing cobalt ferrite nanospheres via hydrothermal technique;
ii. dispersing the nanospheres into a PVDF solution under ultrasonic agitation;
iii. casting the mixture onto a flat substrate and drying to form a flexible nanocomposite film; and
iv. depositing and patterning the radiating patch and CPW feed structure using copper tape, photolithographic or additive manufacturing techniques.
BRIEF DESCRIPTION OF DRAWINGS:
In order to facilitate a comprehensive understanding and practical implementation of the disclosure, reference will now be made to exemplary embodiments illustrated in the accompanying figures. The figures together with detailed description below, are incorporated into and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure:

FIG. 1 illustrates schematic diagram of process of synthesis of CoFe2O4 flower like nanospheres.
FIG. 2 illustrates a) X-ray diffraction spectra, (b), FE-SEM at 10μm and inset of (b) magnified image at 500 nm of prepared cobalt ferrite nanospheres.
FIG. 3 illustrates fabricated antenna using PVDF- CoFe₂O₄ nanocomposite film as a substrate.
FIG. 4 illustrates fabricated Model of the Compact Antenna Compared with a 1 Rupee Coin for Size Reference
FIG. 5 illustrates (a)Reflection loss, (b) Radiation pattern, and (c)3D polar plot of P20CFO antenna.

DETAILED DESCRIPTION OF THE INVENTION
Accordingly, the present invention provides a flexible microstrip antenna with coplanar waveguide fabricated on a PVDF-CFO composite substrate.
The present disclosure can be understood more readily by reference to the following description, taken in conjunction with the accompanying Figures and Examples, all of which form a part of this disclosure
At the very outset of the detailed description, it may be understood that the ensuing description only illustrates a particular form of the invention covered in the present disclosure. However, such a particular form is only an exemplary embodiment, and without intending to imply any limitation on the scope of the invention. Accordingly, the description is to be understood as an exemplary embodiment and teaching of invention and not intended to be taken restrictively.

Before the present disclosure or methods of the present disclosure are described in greater detail, it is to be understood that the specific products, methods, processes, conditions or parameters, are not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the methods. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the methods. Certain ranges are presented herein with numerical values being preceded by the term “about.” The term “about” is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. For example, "about" can mean within one or more standard deviations, or within ± 30%, 25%, 20%, 15%, 10% or 5% of the stated value.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, preferred methods and materials are described. For the purposes of the present invention, the following terms are defined below.

It is appreciated that certain features of the methods, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the methods, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. All combinations of the embodiments are specifically embraced by the present invention and are disclosed herein just as if each and every combination was individually and explicitly disclosed, to the extent that such combinations embrace operable processes and/or composites/scaffolds.

The articles "a" and "an" are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, "an element" means one element or more than one element.

As used herein, the term "comprises", "comprising", or “comprising of” is generally used in the sense of include, that is to say permitting the presence of one or more features or components. The term "comprises", "comprising", or “comprising of” when placed before the recitation of steps in a process or method means that the process or method encompasses one or more steps that are additional to those expressly recited, and that the additional one or more steps may be performed before, between, and/or after the recited steps.

Reference throughout this specification to “certain embodiments”, “further embodiments”, “specific embodiments”, “further specific embodiment”, “one embodiment”, “a non-limiting embodiment”, “an exemplary embodiment”, “some instances”, or “further instances”, means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure.

As used herein, the terms ‘include’, ‘have’, ‘comprise’, ‘contain’ etc. or any form of said terms such as ‘having’, ‘including’, ‘containing’, ‘comprising’ or ‘comprises’ are inclusive and will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illustrate the disclosure and does not pose a limitation on the scope of the disclosure otherwise claimed.

As used herein, the term “invention”, “present invention”, “disclosure” or “present disclosure” as used herein is a non-limiting term and is not intended to refer to any single embodiment of the particular invention but encompasses all possible embodiments as described in the specification.

The terms “process(es)” and “method(s)” are considered interchangeable within this disclosure.

For convenience, certain terms used in the specification and examples are collected in this section below:
PVDF: polyvinylidene fluoride
CoFe₂O₄: cobalt ferrite
CFO: cobalt ferrite
P20CFO: 20 wt% CFO in PVDF
RF: Radiofrequency
XRD: x ray diffraction
FESEM: Field Emission Scanning Electron Microscope
In one specific embodiment, the present invention provides a flexible microstrip patch antenna comprising:
a radiating patch for transmission and reception of electromagnetic waves;
a coplanar waveguide (CPW) fed structure connected to the radiating patch; and
a flexible substrate composed of a nanocomposite material consisting of poly(vinylidene fluoride) (PVDF) and cobalt ferrite (CoFe₂O₄), wherein the cobalt ferrite nanoparticles are uniformly embedded in PVDF.
wherein the overall antenna dimensions are approximately 20 mm × 20 mm in lateral size with a substrate thickness ranging from 70 μm to 100 μm.
In another embodiment, the present invention provides a flexible microstrip patch antenna, wherein the Flower-like cobalt ferrite nanospheres constitute 5% to 20% by weight of the PVDF-CFO composite, significantly improves the bandwidth, gain, crucial for efficient high-frequency antenna performance.
In yet another embodiment, the present invention provides a flexible microstrip patch antenna, wherein the antenna demonstrated an exceptional bandwidth of 12 GHz, covering Ku (12–18 GHz), K band (18–26.5 GHz), and Ka band (26.5–40 GHz).
In yet another embodiment, the present invention provides a flexible microstrip patch antenna, wherein a peak gain of up to 14 dB is achieved when the cobalt ferrite loading in the PVDF matrix is optimized to 20% by weight of the PVDF-CFO composite.
In yet another embodiment, the present invention provides a flexible microstrip patch antenna, wherein the PVDF/CoFe₂O₄ nanocomposite exhibits enhanced dielectric constant and magnetic permeability, contributing to improved antenna gain and bandwidth at microwave and millimetre-wave frequencies.
In yet another embodiment, the present invention provides a flexible microstrip patch antenna, wherein the antenna comprising a radiating element configured to operate at a frequency of 30 GHz, wherein the antenna exhibits a reflection loss of at least -27 dB at said frequency, and further wherein the antenna demonstrates a bidirectional radiation pattern.
In yet another embodiment, the present invention provides a flexible microstrip patch antenna, wherein the antenna is suitable for integration in high-frequency systems such as satellite communication, millimetre-wave radar, and radio frequency (RF) energy harvesting applications.
In yet another embodiment, the PVDF-CFO nanocomposite-based substrate is fabricated using a solution casting method, resulting in a flexible, homogeneous, and defect-free film wherein the method comprises steps of:
i. Adding PVDF powder to N,N Dimethylformamide (DMF) and stir (at around 45–70 °C) for 1-2 hr;
ii. Introducing CoFe₂O₄ (CFO) nanoparticles into the PVDF/DMF solution and continue stirring for an extended period of 12-15 hr;
iii. Pouring or casting the homogeneous PVDF–CFO mixture onto a flat substrate; and
iv. Drying the mixture at around 70 °C for 20 h to evaporate the DMF, forming a solid PVDF/CFO nanocomposite film.
In another embodiment, the present invention provides an easy solution cast method for fabricating the flexible microstrip patch antenna, wherein the method comprising the steps of:
i. synthesizing cobalt ferrite nanospheres via hydrothermal technique;
ii. dispersing the nanospheres into a PVDF solution under ultrasonic agitation;
iii. casting the mixture onto a flat surface petri dish and drying to form a flexible nanocomposite film; and
iv. depositing and patterning the radiating patch and CPW feed structure using copper tape, photolithographic or additive manufacturing techniques.
In yet another embodiment, the present invention discloses that the antenna was designed and analysed using a polymeric nanocomposite comprising polyvinylidene fluoride (PVDF) polymer and cobalt ferrite (CoFe2O4, CFO in short) flower like nanospheres (5-20%), as a substrate, prepared by a solution cast method.
In yet another embodiment, the present invention discloses that the incorporation of flower-like CFO nanospheres (5–20%) into PVDF matrix significantly improves the bandwidth, gain, crucial for efficient high-frequency antenna performance.
In yet another embodiment, the present invention discloses that the antenna demonstrates an exceptional bandwidth of 12 GHz, covering Ku, K, and Ka bands with a peak gain of 14 dB, making it ideal for advanced radar and satellite communication systems.
In yet another embodiment, the present invention discloses that the flexible microstrip patch antenna is compact (20 × 20 mm) and ultra-thin (70–100 μm) (compared to other fabricated antennas), suitable for integration into portable and wearable high-frequency communication systems.
In yet another embodiment, the present invention discloses that there are various industrial applications of the flexible microstrip patch antenna:
Wireless Energy Harvesting Systems: Suitable for powering low-energy IoT and wearable devices using ambient RF energy.
Flexible Communication Devices: Ideal for integration into wearable antennas and flexible communication systems operating in Ku, K, and Ka bands.
Radar and Satellite Technologies: Applicable in compact, high-frequency radar and satellite communication systems due to its wide bandwidth and flexibility.
Multifunctional Electronic Components: Enables development of lightweight, conformal, and multifunctional antenna systems for next-generation electronics.
It is noted that while PVDF and cobalt ferrite have been individually explored for electronic applications, their combined use as a flexible substrate for microstrip patch antennas has not been reported. The development of a functional antenna using highly flexible PVDF-CFO nanocomposites, especially in thin film form via solution casting, overcomes significant fabrication challenges. This integration demonstrates a novel approach to achieving multiband, high-frequency performance in flexible, compact antenna systems
It is further noted that Poly(vinylidene fluoride) (PVDF), a flexible and lightweight polymer, is ideal due to its high dielectric constant, low energy dissipation, and excellent mechanical and electrical properties. Furthermore, its piezoelectric and ferroelectric characteristics can be enhanced by increasing the β-phase content through methods such as electrospinning and electrical and/or magnetic poling. To further improve its functionality, cobalt ferrite (CoFe₂O₄, CFO) was incorporated into PVDF to create a multiferroic nanocomposite. CFO is known for its high magneto crystalline anisotropy, strong coercivity, excellent magnetostrictive coefficient, and chemical stability. Its inclusion in the PVDF matrix not only boosts the β-phase but also adds magnetic responsiveness, enhancing the composite’s overall electromagnetic properties.
Even though we have explained the invention of the present disclosure using specific examples, this explanation is not meant to limit how you understand it. People who are skilled in this field may think of various changes and different versions of the invention after reading this description. We expect that such changes can be made without straying from the main idea or purpose of the invention as defined in the claims.

The present disclosure is further described with reference to the following examples, which are only illustrative in nature and should not be construed to limit the scope of the present disclosure in any manner.

EXAMPLES
The antenna’s performance, as evaluated through parameters such as reflection loss, radiation pattern, and gain, demonstrates its strong potential for use in high-frequency applications, including RF energy harvesting, radar systems, and satellite communications.
Synthesis of CoFe₂O₄ nanospheres:
i. Adding cobalt chloride, iron chloride, urea, and ascorbic acid (AA) to deionized (DI) water;
ii. Stirring the solution for a few hours to ensure complete dissolution;
iii. Transferring the resulting solution to a hydrothermal autoclave and heating at 180 °C;
iv. Collecting the product of hydrothermal reaction and subjecting it to centrifugation to separate the solid phase;
v. Drying the centrifuged product at 80°C;
vi. Calcining the dried product at 500 °C in a furnace;
vii. Collecting the final sample.
(Refer fig 1)
X-ray diffraction:
The XRD pattern of the synthesized CoFe₂O₄ nanospheres/nanoparticles shows distinct peaks corresponding to the (111), (220), (311), (400), (422), (511), (440) and (533) planes (refer figure 2a), confirming the cubic spinel structure which has high magnetic permeability that enhances inductive properties, improves antenna miniaturization and impedance matching. And it further confirmed that cobalt ferrite nanoparticles retain their magnetic properties inside the nanocomposite of polymer PVDF and metal ferrite.
Field Emission Scanning Electron Microscopy:
FESEM analysis revealed nearly spherical nanoparticles with uniform distribution. The images confirmed the absence of significant agglomeration (refer figure 2b).
Antenna design, Fabrication and Testing:

Table-1. Detailed physical dimensions of proposed antennas (same for all nanocomposite films). L, W, Wg, Lg, Sc, Wp, Lp, Ws, Ls, Wf, and Lf are respectively the length of the antenna, width of the antenna, width of the ground plane, length of the ground plane, slot coupling gap or slot center, width of the patch, length of the patch, width of the slot, length of the slot, width of the feedline, length of the feedline.
Parameter L W Wg Lg Sc Wp Lp Ws Ls Wf Lf
Value (mm) 20 20 8 6 4 13 11 6 5 2 7

The fabrication process of the antenna (Fig. 3 and Fig.4) and the associated performance results (Fig. 5a, 5b and 5c) for the PVDF composite containing 20 wt% CFO (P20CFO) are presented below. The antenna exhibits a reflection loss of -27 dB at 30 GHz and demonstrates a bidirectional radiation pattern. Additionally, a maximum gain of 14 dB was achieved. These results suggest that the PVDF/CFO nanocomposite holds strong potential for various advanced applications, including satellite communication systems, military aircraft, and high-frequency technologies.
Reflection loss: Reflection loss (also referred to as return loss) is a critical parameter that indicates how much of the signal is reflected back from the antenna input port rather than being radiated. It’s expressed in decibels (dB) and is derived from the mismatch between the antenna and the connected transmission line. The results are shown in figure 4a.
Radiation pattern: The radiation pattern describes how an antenna emits or receives electromagnetic energy in space. It's a graphical representation showing the intensity or power distribution of radiation as a function of direction (usually in 2D or 3D plots). The results are shown in figure 4b.
3D polar plot of P20CFO antenna: 3D polar plot representing a bidirectional radiation pattern, results are shown in figure 4c.
Advantages
Compact and Flexible Design: The antenna’s small size (20 × 20 mm) and thin profile (70–100 µm) allow easy integration into wearable and flexible electronic systems.
Multifunctional Substrate Material: PVDF-CFO nanocomposites provide combined dielectric, piezoelectric, and magnetic properties, enhancing antenna performance.
Wide Frequency Coverage: Demonstrates a broad bandwidth (up to 12 GHz), covering Ku, K, and Ka bands, suitable for high-frequency applications.
Enhanced Energy Harvesting Efficiency: Optimized antenna design improves RF energy capture, addressing the low energy density challenge in RF harvesting systems.
Simple and Scalable Fabrication: Solution casting offers a cost-effective, reproducible method to fabricate high-performance flexible antennas.

The inventors have developed the invention, so that advantage can be achieved in an economical, practical, and facile manner. While preferred aspects and example configurations have been shown and described, it is to be understood that various further modifications and additional configurations will be apparent to those skilled in the art. It is intended that the specific embodiments and configurations herein disclosed are illustrative of the preferred nature of the invention and should not be interpreted as limitations on the scope of the invention.
, Claims:We claim
1. A flexible microstrip patch antenna comprising:
a radiating patch for transmission and reception of electromagnetic waves;
a coplanar waveguide (CPW) fed structure connected to the radiating patch; and
a flexible substrate composed of a nanocomposite material consisting of poly(vinylidene fluoride) (PVDF) and cobalt ferrite (CoFe₂O₄), wherein the cobalt ferrite nanoparticles are uniformly embedded in PVDF.
wherein the overall antenna dimensions are approximately 20 mm × 20 mm in lateral size with a substrate thickness ranging from 70 μm to 100 μm.
2. The flexible microstrip patch antenna as claimed in claim 1, wherein the Flower-like cobalt ferrite nanospheres constitute 5% to 20% by weight of the PVDF-CFO composite, significantly improves the bandwidth, gain, crucial for efficient high-frequency antenna performance.

3. The flexible microstrip patch antenna as claimed in claim 1, wherein the antenna demonstrated an exceptional bandwidth of 12 GHz, covering Ku (12–18 GHz), K band (18–26.5 GHz), and Ka band (26.5–40 GHz).

4. The flexible microstrip patch antenna as claimed in claim 1, wherein a peak gain of up to 14 dB is achieved when the cobalt ferrite loading in the PVDF matrix is optimized to 20% by weight of the PVDF-CFO composite.
5. The flexible microstrip patch antenna as claimed in claim 1, wherein the PVDF/CoFe₂O₄ nanocomposite exhibits enhanced dielectric constant and magnetic permeability, contributing to improved antenna gain and bandwidth at microwave and millimetre-wave frequencies.

6. The flexible microstrip patch antenna as claimed in claim 1, wherein the antenna comprising a radiating element configured to operate at a frequency of 30 GHz, wherein the antenna exhibits a reflection loss of at least -27 dB at said frequency, and further wherein the antenna demonstrates a bidirectional radiation pattern.

7. The flexible microstrip patch antenna as claimed in claim 1, wherein the antenna is suitable for integration in high-frequency systems such as satellite communication, millimetre-wave radar, and radio frequency (RF) energy harvesting applications.

8. A solution cast method for fabricating the flexible microstrip patch antenna (using copper tape) as claimed in claim 1, wherein the method comprising the steps of:
i. synthesizing cobalt ferrite nanospheres via hydrothermal technique;
ii. dispersing the nanospheres into a PVDF solution under ultrasonic agitation;
iii. casting the mixture onto a flat surface petri dish and drying to form a flexible nanocomposite film; and
iv. depositing and patterning the radiating patch and CPW feed structure using copper tape photolithographic or additive manufacturing techniques.