Radio Frequency Region Research Articles

Simultaneous epsilon-negative and mu-negative property of Ni/CaCu3Ti4O12 metacomposites at radio-frequency region

Metacomposites with simultaneous epsilon-negative and mu-negative property have drawn tremendous attentions due to their promising applications in electromagnetic field. Herein, Ni/CaCu3Ti4O12 (Ni/CCTO) metacomposites were prepared by low-temperature pressureless sintering method. It was observed that Ni chains were gradually interconnecting to each other with increasing Ni content, and a percolation behavior was observed. Epsilon-negative property was obtained above percolation threshold attributing to the synergistic effect of induced electric dipole and low-frequency plasma oscillation in Ni networks, which was explained by the superposition of Drude and Lorentz model. Mu-negative property was observed above ∼34 MHz and ∼120 MHz for 60 wt% and 70 wt% Ni/CCTO composites respectively, which may originate from the combined effects of diamagnetic response, domain wall motion and gyromagnetic spin rotation. Hence, simultaneous epsilon-negative and mu-negative property at radio-frequency region was realized in Ni/CCTO metacomposites. Besides, the composites presented hopping conduction behavior, and then changed into metal-like conduction behavior with increasing Ni content. The impedance response of Ni/CCTO composites clarified the correlation between epsilon-negative and inductive character. This work could broaden the scope of metacomposites and pave its way to potential applications of electromagnetic shielding, novel antenna, and high-k capacitors.

Coherent Dual-Band Radar-Over-Fiber Network With VCSEL-Based Signal Distribution

Today, the advent of radar sensing in applications requiring ever higher precision, such as automotive and industrial monitoring, needs the development of systems with superior resolution, stability and accuracy on 2D/3D spaces. Multiple-input–multiple-output (MIMO) radar systems have been studied for more than twenty years, proving to achieve excellent resolutions by merging simultaneous observations from sparse multiple radars. In addition, long-term frequency/phase coherence among distributed signals to and from remote and widely distributed radar frontends, enables a centralized architecture where, in a common base station (BS) site, all the received signals can be coherently processed in synergy, allowing to further improve detection, localization, and imaging capabilities. Radio-over-fiber (RoF) solutions represent an enabling technology for guaranteeing coherence among all radar signals coherently generated in the BS and distributed/collected to/from the radar heads by means of optical fiber links. Despite the unprecedented frequency-agility provided by photonics-based radiofrequency (RF) up-/down-conversion in the optical domain, for applications requiring massive low-cost production and power efficiency, such as advanced driver-assistance systems, it might be convenient to transmit and receive conventionally generated RF signals, and to limit the use of photonics, as in RoF, to RF signal distribution through cheap high-capacity optical links, in order to avoid EM interference, minimize loss, signal distortion and link encumbrance, still keeping the coherence among distributed signals. In this work, we present a MIMO radar-over-fiber (RaoF) network, where a common BS transmits and receives RF signals through optical standard single-mode fiber (SSMF), to and from two remote radar transmitters (TXs) and four receivers (RXs), all remote with respect to the BS and distributed on a 3 m-long baseline, and employing cheap patch antennas. Electro-optic conversion is achieved through direct modulation (DM) of low-cost, power-effective, and high-speed vertical-cavity surface-emitting lasers (VCSELs) working in the 1.3 µm-wavelength regime. Such a wavelength ensures propagation over SSMF with negligible distortions up to the km-range. The system is tested in a down-scaled indoor scenario and an RF carrier of 8.5 GHz is used, due to the limited frequency response of the employed VCSELs. System performance is evaluated with 1.4 GHz-bandwidth signals, comparing non-coherent and coherent signal elaboration. In addition, dual-band operation in the same RF region is tested, confirming that VCSEL-based optical links are a viable way to guarantee phase coherence among the distributed signals and among multiple frequency bands. Coherent MIMO processing also confirm the potential to achieve superior range and cross-range resolution than non-coherent data fusion.

Tunable negative permittivity of Bi2O3–SiO2/MWCNT glass-nanocomposites at radio frequency region

In this work, the negative dielectric constant in the frequency range 1 MHz to 3 GHz and the temperature range 140 K to 300 K are studied. The dielectric parameters (e′, e″, tanδ), conductivity ( $${\sigma }_{\text{ac}}$$ ), reactance (Z′, Z″), and magnetization (Ms) with respect to the multiwall carbon nanotube (MWCNT) loading are discussed in detail. A percolation phenomenon in ac conductivity ( $${\sigma }_{\text{ac}}$$ ) is noticed when the MWCNT content increased from 5 to 10 wt%. The perceived ac conductivity spectra of various trends of present BS/MWCNT glass-nanocomposites are explained by Jonscher’s power law or Drude model. The negative permittivity is observed with the formation of the 3D conductive network, and negative value and frequency range of the real part of permittivity (e′) are precisely adjusted by varying concentration of MWCNT. The resonance frequency-dependent negative permittivity behaviour in the BS/MWCNT glass-nanocomposite with low content MWCNT can be explained by Lorentz model, and the plasma-like negative permittivity behaviour was explained by Drude model. This work offers a favourable outcome to tunable negative dielectric behaviour and high dielectric constant materials.

Communication—Tunable and Weakly Epsilon-Negative Property Realized by Metallic Granular Metacomposites at Radio-Frequency Region

We fabricated metallic granular metacomposites by low-temperature pressureless sintering. A percolation behavior appears, corresponding to the observation of metal-like conductivity and epsilon-negative. Weakly epsilon-negative property is achieved in 70 wt% FeCrNi/CaCu3Ti4O12 metacomposites, showing small absolute value of epsilon between 0 and −150. The epsilon-negative property is tuned by adjusting metal content in metacomposites and high negative value of real permittivity (∼−104) is achieved. The superposition of Lorentz and Drude model explains the radio-frequency (RF) epsilon-negative. Epsilon-negative property correlates with inductive character as investigated by equivalent circuit analysis. Our work benefits the practical applications of epsilon-negative property in electromagnetic fields.

Performance-Issues-Mitigation-Techniques for On-Chip-Antennas – Recent Developments in RF, MM-Wave, and Thz Bands With Future Directions

The need for a compact, economical, and low-power wireless system has given birth to the System-on-Chip (SoC) concept viable of a multitude of innovative applications. On-Chip-Antennas (AoCs) are an integral part of the SoC based wireless system and have got a remarkable attention since last one decade. In contrary to off-chip-antennas, AoCs are fabricated and integrated on the same substrate where the other components of the wireless system are fabricated. This integration results in several challenges besides highly desired benefits. The most serious challenge is the degradation in AoC’s key performance metrics, i.e. gain and radiation efficiency because of low-resistivity and high-permittivity of the Silicon substrate which is the optimized choice for the AoC design. This triggers a need for the use of novel methods for the mitigation of these performance issues. Consequently, a variety of such innovative methods have been proposed in the literature. However, a critical description on the recent developments in these methods at one place to facilitate a wide range of researchers is missing. Therefore, this article presents a well-organized and systematic survey on the recent advancements of the AoC’s performance-issues-mitigation-methods for wireless applications in Radio Frequency (RF), Millimeter-Wave (MM-Wave), and Terahertz (THz) bands for the first time. A concise description of future directions with respect to AoCs performance enhancement methods is also part of this article. It is anticipated that the critical presentation of these methods will make this article a valuable guide for a wide spectrum of researchers, who want to adventure with the tough task of high performance AoC design. In addition, it is envisioned that this article will pave a promising path for a further dominance of the AoCs in RF, MM-Wave, and THz regions.

Two novel low permittivity microwave dielectric ceramics Li2TiMO5 (M = Ge, Si) with abnormally positive τf

Two tetragonal natisite structured Li2TiMO5 (M = Ge, Si) ceramics fabricated using the conventional solid-state reaction method were investigated in terms of the thermal stability, sintering behavior and dielectric properties at radio (RF) and microwave frequency region. At the optimum sintering temperature of 1140 °C, Li2TiGeO5 (LTG) has εr ˜ 9.43, Q × f ˜ 65,300 GHz (at 14.7 GHz), and τf ˜ +24.1 ppm/°C, while Li2TiSiO5 (LTS) sintered at 1180 °C exhibits εr ˜ 9.89, Q × f ˜ 38,100 GHz (at 14.2 GHz), and τf ˜ +50.1 ppm/°C. The positive τf values of the present LTG and LTS are abnormal and extremely important for low-εr microwave dielectric ceramics, which could behave as a promising τf compensator. Moreover, the dielectric spectra of both ceramics revealed a phase transition at low-temperature, exhibiting a dielectric peak, which could account for the negative τε and positive τf in operating temperature ranges.

Tunable negative permittivity in Ti3SiC2 MAX phase/Polymethyl methacrylate metacomposites at radio-frequency region

Metacomposites with negative permittivity have triggered tremendous fundamental and practical attention in recent years. In this paper, Ti3SiC2 MAX phase/Polymethyl methacrylate (PMMA) metacomposites with different Ti3SiC2 content were prepared. Weakly negative permittivity value (between [Formula: see text] and 0) was observed near percolation (Ti3SiC2 content of 60[Formula: see text]wt.%), attributing to moderate carrier concentration in Ti3SiC2 networks, and negative permittivity was tuned by tailoring conductive Ti3SiC2 networks. AC conductivity spectra and negative permittivity spectra of composites over percolation were explained by Drude model, indicating metal-like conduction behavior and low-frequency plasmonic oscillation in composites. The impedance response of composites was analyzed by equivalent circuit models, manifesting correspondence between inductor and negative permittivity. This work presented a new type of metacomposite constructed by Ti3SiC2 MAX phase and further revealed the generation mechanism of negative permittivity, which will greatly facilitate the practical applications of MAX phase in metacomposites.

Dual frequency comb photon echo spectroscopy

Dual frequency comb (DFC) nonlinear spectroscopy is an emerging technique that can be used to study a variety of molecular nonlinear responses by exploiting the automatic pulse-to-pulse time delay scanning and fast data acquisition characteristics of the DFC techniques. Here, we propose a DFC-based photon echo spectroscopy (DFC-PES), where two optical frequency comb lasers have slightly different repetition rates and are also allowed to have different carrier frequencies. We first demonstrate our theoretical approach for DFC linear spectroscopy. Then, the signals expected from the proposed DFC-PES are theoretically calculated. The slight offset in the pulse repetition rates enables asynchronous optical sampling and automatic scanning of the time intervals between different field–matter interaction events, making frequency tuning unnecessary. Analytic expression of the third-order photon echo signal is demonstrated in two frequency dimensions for a simple two-level model system. The signal has a well-defined and simple connection to the underlying third-order response function and exhibits the expected down-conversion features from the optical frequency into the radio frequency region with a down-conversion factor that is experimentally controllable.

Electromagnetic Interference Shielding Analysis of Conducting Composites in Near- and Far-Field Region

The main objective of this paper is to develop a conducting composite sheet for coating of various electronic devices to provide effective electromagnetic interference (EMI) shielding in medical and defence application in near- and far-field region. Here, we utilize the dielectric properties of styrene acrylonitrile (SAN) copolymer and graphite (Gr) conducting composites in radio frequency ranges (10 MHz–1 GHz) for calculating EMI shielding properties. The SAN–Gr conducting composite sheets were prepared by mechanical mixing and the hot compression mold technique. The SAN–Gr conducting composites exhibited high dielectric constants $(\varepsilon^\prime)$ , high dissipation factors $(\tan \delta)$ , and high ac conductivities $(\sigma)$ in radio frequency regions. The main advantage of these composites incorporates their lightweight and low cost. The absorption loss ( A ), reflection loss ( R ), rereflection correction factor ( C ), and electromagnetic interference shielding effectiveness of the SAN–Gr conducting composite sheets were evaluated theoretically using $\varepsilon^\prime $ , tan $\delta $ , and $\sigma $ for near- and far-field region. For electromagnetic compatibility in near- and far-field region (electric field, magnetic field, and plane wave), the adequate shielding effectiveness in the frequency range of 10 MHz–1 GHz of the SAN–Gr conducting composites was obtained with addition of Gr content.

Space-time focusing in a highly multimode fiber via optical pulse shaping.

Fields propagating through a highly scattering material will be distorted in both space (intensity speckles) and time (spectral and temporal speckles), inhibiting tasks such as imaging and communication in both the optical and radio frequency regions. In optics, research thus far has demonstrated spatial focusing, image transmission, and short pulse delivery through bulk scattering materials and multimode fibers by taking advantage of spatial wavefront-shaping techniques. Here, we exploit spectral phase shaping for reference-free characterization of spectral and temporal speckle, and space-time focusing of broadband ultrafast pulses distorted by modal dispersion in a multimode fiber. We show that temporal speckle fields at different multimode fiber output locations are uncorrelated and demonstrate the ability to focus a short pulse at a specific output spatial location, while keeping the field at other output locations noise-like, offering opportunities to expand multimode fiber imaging and communication capacity.

Meta-composites: NiO supported 3D carbon networks structured by 1D building blocks towards tailorable negative permittivity

Meta-composites have drawn significant attention due to their preferable applications in electronic devices and promising mass production-scale. Compared with metallic particles as common conductive units in metamaterials or meta-composites fabrication, one-dimensional (1D) carbonaceous building blocks [e.g. multi-walled carbon nanotubes (MWCNTs) or carbon fibers] could provide preferable alternations. In this paper, nickel-modified carbon fibers and MWCNTs were served as 1D building blocks to fabricate meta-composites. Negative permittivity behavior in meta-composites were investigated at radio-frequency region. Herein, two different types of negative permittivity (i.e. dipole-type and plasma-type) were observed and analyzed by Lorentz model and Drude model respectively. Different variation trends of alternative conductivity spectra were followed by Jonscher’s power law or Drude model, indicating conductive mechanism change from hopping conduction to metal-like conduction. Equivalent circuit analysis to impedance response of meta-composites manifested correspondence between inductive characteristic and negative permittivity. This work not only presents novel routes to meta-composites designations by 1D carbon building blocks, but also further clarifies negative permittivity generation mechanism, which will facilitate applications in impedance matching, electromagnetic shielding and multi-layer high-k capacitors etc.

Low-temperature sintering Graphene/CaCu3Ti4O12 nanocomposites with tunable negative permittivity

Since negative permittivity demonstrated in metamaterials, how to effectively tune negative permittivity still the challenge to satisfy practical applications. Meta-composites could provide alternative routes to tunable negative permittivity. In this paper, Graphene/CaCu3Ti4O12 (GR/CCTO) meta-composites with different GR content were fabricated by low-temperature pressureless sintering. Microstructures and compositions of GR/CCTO were investigated in detail. The electrical and dielectric properties of GR/CCTO nanocomposites were investigated at 10 kHz −1 MHz and 20 MHz - 1 GHz region respectively. AC conductivity spectra showed different variation trends which were explained by Jonscher's power law or Drude model, indicating conductive mechanism transformation from hopping conduction to metal-like conduction. Lorentz-type and/or Drude-type negative permittivity behaviors were observed at radio-frequency region. Tunable negative permittivity were realized by changing GR content in GR/CCTO nanocomposites. Correspondence between inductive characteristic and negative permittivity was manifested by equivalent circuit analysis of impedance response of GR/CCTO composites. This work not only presents novel routes to tune negative permittivity, but also further clarifies negative permittivity generation mechanism, which will greatly facilitate applications in impedance matching, electromagnetic shielding and multi-layer high-k capacitors etc.

Wide range dielectric and infrared spectroscopy of (Nb+In) co-doped rutile ceramics

The dielectric response of ceramics of co-doped rutile $\mathrm{T}{\mathrm{i}}_{1\text{\ensuremath{-}}x}{(\mathrm{N}{\mathrm{b}}_{0.5}\mathrm{I}{\mathrm{n}}_{0.5})}_{x}{\mathrm{O}}_{2}$ has been measured via a combination of impedance, high-frequency coaxial, terahertz transmission, and infrared reflectivity spectroscopies spanning 15 decades of frequency between 0.1 Hz and 240 THz. It is argued that the colossal dielectric permittivity reported by Hu et al. [Hu et al., Nat. Mater. 12, 821 (2013)] has the same explanation as in the original colossal permittivity material $\mathrm{CaC}{\mathrm{u}}_{3}\mathrm{Ti}{\mathrm{O}}_{4}{\mathrm{O}}_{12}$ (CCTO), namely, a combination of the internal barrier layer capacitor (IBLC) and the surface barrier layer capacitor (SBLC) effects. The IBLC effect is caused by a microstructure consisting of insulating grain boundaries (thickness \ensuremath{\sim}1 nm and conductivity of $\ensuremath{\sim}{10}^{\ensuremath{-}6}\phantom{\rule{0.16em}{0ex}}\mathrm{S}/\mathrm{cm})$ surrounding interior regions of bulk conductivity approximately equal to ${10}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}\mathrm{S}/\mathrm{cm}$. The SBLC effect is the result of a depletion layer adjacent to the contacts approximately 100 nm thick with conductivity of $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}\phantom{\rule{0.16em}{0ex}}\mathrm{S}/\mathrm{cm}$. The SBLC and IBLC effects give rise to dielectric relaxations in low-frequency and radiofrequency regions, respectively. The temperature dependence of both relaxation rates measured down to 20 K is thermally activated. No separate absorption process has been observed that could be linked to giant defect dipoles. Infrared spectroscopy has revealed four weak defect-related modes at frequencies close to the Raman mode frequencies of rutile, activated in the infrared through a symmetry-breaking process. Co-doping produces a significant loss in the partial spectral weight between 75 and $350\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$ associated with the lowest transverse optical mode, which softens on cooling. The loss in its spectral weight corresponds to the gain in near-infrared spectral weight, previously assigned to small polaron absorption.

Refractive-index-sensing optical comb based on photonic radio-frequency conversion with intracavity multi-mode interference fiber sensor.

Optical frequency combs (OFCs) have attracted attention as optical frequency rulers due to their tooth-like discrete spectra together with their inherent mode-locking nature and phase-locking control to a frequency standard. Based on this concept, their applications until now have been demonstrated in the fields of optical frequency metrology. However, if the utility of OFCs can be further expanded beyond their application by exploiting new aspects of OFCs, this will lead to new developments in optical metrology and instrumentation. Here, we report a fiber sensing application of OFCs based on a coherent link between the optical and radio frequencies, enabling high-precision refractive index measurement based on frequency measurement in radio-frequency (RF) region. Our technique encodes a refractive index change of a liquid sample into a repetition frequency of OFC by a combination of an intracavity multi-mode-interference fiber sensor and wavelength dispersion of a cavity fiber. Then, the change in refractive index is read out by measuring the repetition frequency in RF region based on a frequency standard. Use of an OFC as a photonic RF converter will lead to the development of new applications in high-precision fiber sensing with the help of functional fiber sensors and precise RF measurement.

Heat transfer of PEGylated cobalt ferrite nanofluids for magnetic fluid hyperthermia therapy: In vitro cellular study

Hyperthermia generally means as increasing the temperature of particular region of body to rise 5 °C above the body’s physiological temperature. Here, we investigate the thermal therapy of PEGylated cobalt ferrite nanoparticles prepared by hydrothermal approach on cancerous cell line in the alternative current magnetic field. To characterize of the magnetic nanoparticles (MNPs), scanning electron microscopy, dynamic light scattering, X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometer were used. X-ray diffraction analysis confirmed the spinel phase formation of the MNPs. Cytotoxicity of MNPs using MTT assay on L929 cell lines showed the PEGylated MNPs extraordinary biocompatibility. Specific loss power (SLP) were calculated for neat and PEGylated MNPs in aqueous solution in radio frequency region (300–400 kHz). Power absorbed by neat and PEGylated cobalt ferrite were measured as a function of frequency and MNPs concentration. The maximum SLP was 31.8 W/g for coated nanoparticles (MNPs + PEG) in concentration of 0.0025 gr/mL at applied frequency of 350 kHz. Magnetic fluid hyperthermia of MCF7 breast cancer cells were shown up to 90 percent of cell death in 350 kHz. Simulation studies approved the elevated temperature of the PEGylated MNPs to 42 °C in the tumor after 10 min of MNPs intratumorally injection. This study shows increase in rate of heating in the tumor when the temperature of injected MNPs is approximately equal to the body temperature (i.e. 37 °C).

Tunable negative permittivity and permeability of yttrium iron garnet/polyaniline composites in radio frequency region

The present work demonstrated the tunable negative permittivity and permeability properties of a two-phase composite material consisting of conductive matrix [polyaniline (PANI)] and magnetic filler [yttrium iron garnet (YIG)]. The negative permittivity observed in the YIG/PANI composites is accompanied by the formation of conductive PANI network, which induced the plasma oscillation of carriers in PANI obeying the Drude model. Through theoretical calculation, negative permeability can be realized and further adjusted by external magnetic field via the domain wall and spin resonances of YIG.

Multiple pulse coherent dynamics and wave packet control of the N2 a'' 1Σ dark state by attosecond four-wave mixing.

Nonlinear multidimensional spectroscopy is ubiquitous in the optical and radio frequency regions as a powerful tool to access structure and dynamics. The extension of this technique into the extreme ultraviolet (XUV) region with attosecond pulses holds promise for probing electronic dynamics and correlations with unprecedented time and spatial resolution. In this work, we use noncollinear four-wave mixing of a weak XUV attosecond pulse train (11-17 eV) and few-femtosecond NIR pulses (800 nm) to spectroscopically and dynamically probe the dipole-forbidden double-well potential of the a'' 1∑+g electronic state of nitrogen. The results demonstrate optical coupling of the inner and outer limits of the initial XUV-prepared vibrational wave packet in the valence character b' 1∑+u state to the inner and outer wells, respectively, of the a'' 1∑+g double well state by 800 nm light. Two four-wave mixing schemes with different pulse timing sequences and noncollinear beam geometries are used (one NIR pulse collinear and one NIR pulse noncollinear versus both NIR pulses noncollinear to the XUV beam) to measure the a'' dark state energetic structure and to control the dynamical preparation and motion of a dark state wave packet by selective population of either the inner Rydberg or outer valence-character potential well. Experimental measurements of the a'' 1∑+g outer well vibrational spacing and anharmonicity closely match the values theoretically predicted for this previously unobserved state.

Hyperthermia Dosing and Depth of Effect

The penetration depth in the electromagnetic heating could be a crucial factor of its application, when the deep heating is the goal. The capacitive coupling is one of the most popular heating techniques in radiofrequency (RF) heating applications. The matching of the target defines the penetration possibilities. The current matched solution has deeper mathematically defined penetration in RF region than the capacitive plane-wave solution. The same power of application request high voltage with relatively low current for plane-wave inducing, while in current matching it has low voltage with high current. The effective depth of the action in the two solutions do not identical, the penetration defined by the intensity of 1/e portion of the incident beam is higher in the current-matched techniques.

Tailorable radio-frequency negative permittivity of titanium nitride sintered with different oxidation pretreatments

Titanium nitride (TiN) with high-temperature plasmonic property can be a promising candidate for metamaterials at radio-frequency region. In this paper, pure TiN powders were pretreated by a facile oxidation process. The introduced titanium oxide was in favor of sintering of TiN, and further controlled the dielectric properties of TiN bulks. The radio-frequency (10MHz-1GHz) permittivity spectra of the obtained samples were investigated in detail. Negative permittivity was achieved using TiN based ceramic and it was tailorable by the oxidation temperatures of powders before sintering. The negative permittivity induced by plasma oscillations of conductive electrons was analyzed by Drude model. Interestingly, the zero-crossing points of permittivity from negative to positive were depend on the porous microstructure and weakly conductive titanium oxynitride, as well as the scattering effect by grain boundaries and impurity atoms. The conduction loss is dominant in determining the high dielectric loss. The realization of tunable negative permittivity using TiN gives a new and simple method to achieve negative electromagnetic parameters in single-phase materials.

Low and high frequency shielding effectiveness of PVC-PPy films

In the present communication, an attempt is made to study the structural, morphological, thermal, low (100 Hz–2 MHz) and high (12.4–18 GHz) frequency dielectric properties of PVC films doped with various weight percentage concentrations of PPy. RFI/EMI shielding effectiveness of these films is also evaluated form the dielectric data. The structural study of the films reveals their amorphous nature. Morphological analysis confirms the growth of conductive phase of PPy in PVC on increasing the PPy content. Thermogravimetric analysis of the films show that the thermal stability of films improves on loading PVC films with PPy. Low and high frequency dielectric characterization of the films show that on increasing weight percentage concentration of PPy in PVC values of dielectric constant, dielectric loss and ac conductivity increase. Study of radio frequency/electromagnetic shielding effectiveness of these films show that these films act as reflective medium in low frequency region and as an absorptive medium in high frequency region. Of all the compositions studied, PVC film with 40% weight concentration of PPy acts as the best reflective shield in radio frequency region and it acts as good absorptive shielding material in the microwave region offering highest and almost constant SET of around −19 dB. This suggests that this composition can be effectively utilized for shielding purposes in both low and high frequency regions.