Solid-state fractional capacitor using MWCNT-epoxy nanocomposite

Abstract

Here, we propose the fabrication of a solid state fractional capacitor for which constant phase (CP) angles were attained in different frequency zones: 110 Hz–1.1 kHz, 10 kHz–118 kHz, and 230 kHz–20 MHz. The configuration makes use of epoxy resin as the matrix in which multi-walled carbon nanotubes (MWCNTs) are dispersed. Adhesive nature of the epoxy resin is utilized for binding the electrodes, which avoids the extra step for packaging. The fractional capacitive behavior is contributed by the distribution of time constants for the electron to travel from one electrode to the other. The distributive nature of the time constant is ensured by inserting a middle plate which is coated with a porous film of polymethyl-methacrylate in between the two electrodes. The phase angle trend for the configuration is studied in detail, and it is observed that as the % of carbon nanotubes (CNTs) loading increases, the CP angle increases from −85° to −45° in the frequency zones above 100 Hz. The developed device is compact and it can be easily integrated with the electronic circuits.

Comparative Study of Discrete Component Realizations of Fractional-Order Capacitor and Inductor Active Emulators

“…Unfortunately, these elements are not yet commercially available [17][18][19] and, therefore, they have to be approximated by appropriate integer-order networks. A possible solution for approximating fractional-order capacitors is the employment of an RC network, [20][21][22] but this su®ers from the requirement for re-designing the network in order to change the characteristics of the fractional-order element.…”

Partial fraction expansion–based realizations of fractional‐order differentiators and integrators using active filters

“…The direct method for implementing such blocks is by substitution of the ideal capacitors in the conventional (ie, integer‐order) structures with fractional‐order capacitors. However, fractional‐order capacitors are not yet commercially available . Thus, the approximation of the capacitors through appropriately configured RC networks is a first solution for overcoming the aforementioned obstacle .…”

An ultra-broadband single-component fractional-order capacitor using MoS2-ferroelectric polymer composite

“…[1][2][3][4][5][6][7][8][9][10][11] Thanks to the additional parameter, namely, the fractional order (see supplementary material Sec. S1 and Fig.…”

“…To alleviate these bottlenecks, a method, which realizes the response of the RC network, using a microscale structure consisting of polyvinylidene fluoride (PVDF) ferroelectric polymer composites embedding carbon-based nanomaterials, particularly reduced graphene oxide (rGO) sheets and multi-walled carbon nanotubes (MWCNTs), has been employed. 1,3,30 The constant phase angle (CPA) of the impedance of an FOC, which is fabricated using any one of these composites, can be controlled by changing the volume ratio of the fillers and the type of polymer in the composite. It should be noted here that the term CPA comes from the assumption that the phase angle of the FOC's impedance remains unchanged in a frequency band.…”

“…It is important to mention here that, previously developed FOCs do not only suffer from narrow CPZs but also have other shortcomings that limit their use in modern electronic devices and systems. For instance, liquid electrode based (LEB) FOCs cannot be integrated with microelectronics, 6 the CPA of fractal tree (FT) FOCs cannot be tuned, 11 the FOCs making use of operational trans-conductance amplifiers (OTAs) are power hungry, [47][48][49] and the CPA of the FOCs fabricated using carbon-ferroelectric polymer composites is very sensitive to the filler ratio of the carbon 1,3 and it has a low dynamic range. 46 On the other hand, the FOCs proposed in this work are fully compatible with PCBs, passive, and have a stable CPA over a broader frequency range.…”