Fractal Inductor Research Articles

Laser Direct Structured 3D Circuits on Silicone.

Silicone rubber is a biocompatible elastomeric polymer, with great potential for mechanical and biologic sensing applications, if electrical circuits can be reliably integrated. Laser direct structuring is a bottom-up circuit fabrication process, whereby copper is chemically grown on laser exposed regions of a modified substrate, promoting adhesion by laser roughening the circuit tracks. In this Research Article, we successfully demonstrate this process using superflexible biocompatible silicone (30 hardness on Shore 00) with copper chromite additive, cast into both 2D planar and 3D contour substrates. A horseshoe pattern circuit, meander and Hilbert fractal inductors, and a 3D hemispherical helix trace are fabricated and tested. The range of laser power and copper chromite concentration are explored. Mechanical testing is performed to determine breakage strain and elastic modulus. Material stiffness and trace peel strength are shown to increase with copper chromite concentration. Peel strength is measured to be very high, from approximately 1 to 5 kN/m, depending on dopant loading. With high adhesion and conductivity, the simple laser-writing process presented here enables high-quality circuit integration into elastomeric silicone.

High-quality factor multipath differential fractal inductor for wireless applications

PurposeThe purpose of this study is to develop a high-quality factor fractal inductor for wireless applications such as satellite, WLAN, Bluetooth, microwave, radar and cellular phone.Design/methodology/approachThe Hilbert fractal curve is used in the implementation of the proposed inductor. In the proposed inductor, the metal width has split into multiple paths based on the skin depth of the metal. The simulations of the proposed inductor are performed in 180 nm CMOS technology using the Advanced Design System EM simulator.FindingsThe multipath technique reduces the skin effects and proximity effects, which, in turn, decreases the series resistance of the inductor and attains high-quality factor over conventional fractal inductor for the equal on-chip area.Research limitations/implicationsThe width of the path has chosen higher than the skin depth of the metal for a required operating frequency. Due to cost constraints, the manufacturing of the proposed fractal inductor is limited to a single layer.Practical implicationsThe proposed inductor will be useful for the implementation of critical building blocks of radio frequency integrated circuits and monolithic microwave integrated circuits such as low-noise amplifiers, voltage-controlled oscillators, mixers, filters and power amplifiers.Originality/valueThis paper presents for the first time the use of a multipath technique for the fractal inductors to enhance the quality factor.

Modeling and Performance Analysis of Planar Fractal Inductors

Limited available space and some other system requirements for the integration of magnetic components address the importance to improve their overall performance and reduce losses. This article evaluates the performance of planar inductor with Moore fractal design. The inductor is modeled using partial inductance method, where each segment is divided into a certain number of elementary filaments, and then, mutual inductances between filaments are calculated. A developed simulation tool is used for the analysis of high-frequency parameters (equivalent inductance, equivalent resistance, and quality factor), taking into account parasitic effects. The proposed model is verified by measurements and electromagnetic simulations. Two planar fractal inductors, with different segment widths, 2.9 and 3.6 mm, are examined. A good agreement between the results obtained by modeling, measurements, and electromagnetic simulations is achieved. The main advantage of the proposed simulation tool is that it can be easily modified and applied for the modeling and optimization of various inductor geometries, which will be useful in future research.

High quality factor fractal inductor with complementary split-ring array inclusion

PurposeThis paper aims to present an efficient method to improve quality factor of printed fractal inductors based on electromagnetic band-gap (EBG) surface.Design/methodology/approachHilbert fractal inductor is designed and simulated using high-frequency structural simulator. To improve the quality factor, an EBG surface underneath the inductor is incorporated without any degradation in inductance value.FindingsThe proposed inductor and Q factor are measured based on well-known three-dimensional simulator, and the results are compared experimentally.Practical implicationsThe proposed method was able to significantly decrease the noise with increase in the speed of radio frequency and sensor-integrated circuit design.Originality/valueFractal inductor is designed and simulated with and without EBG surfaces. The measurement of printed circuit board prototypes demonstrates that the inclusion of split-ring array as EBG surface increases the quality factor by 90 per cent over standard fractal inductor of the same dimensions with a small degradation in inductance value and is capable of operating up to 2.4 GHz frequency range.

Design of a high performance narrowband low noise amplifier using an on-chip orthogonal series stacked differential fractal inductor for 5G applications

Design of a high performance narrowband low noise amplifier using an on-chip orthogonal series stacked differential fractal inductor for 5G applications

A novel hybrid series stacked differential fractal inductor for MMIC applications

Purpose The purpose of this paper is to design an on-chip inductor with high inductance, high-quality factor and high self-resonance frequency for the equivalent on-chip area using fractal curves. Design/methodology/approach A novel hybrid series stacked differential fractal inductor using Hilbert and Sierpinski fractal curves is proposed with two different layers connected in series using vias. The inductor is implemented in Sonnet EM simulator using 180 nm CMOS standard process technology. Findings The proposed inductor reduces the parasitic capacitance and negative mutual inductance between the adjacent layers with significant improvement in overall inductance, quality factor and self-resonance frequency when compared with conventional series stacked fractal inductors. Research limitations/implications The fractal inductor is used to create high inductance in the single-layer process, but access to multilayers is restricted owing to unusual and expensive fabrication processes. Practical implications The proposed inductor can be used in implementation of low noise amplifier, voltage controlled oscillators and power amplifiers. Originality/value This paper introduces a combination of two fractal curves to implement a hybrid fractal inductor that enhances the performance of the inductor.

Compact metamaterial inspired conformal dual‐band antenna loaded with meander lines and fractal shaped inductor for Wi‐Fi and WiMAX applications

In this study, a novel metamaterial inspired compact cylindrical conformal dual-band antenna with a shunt fractal inductor and bottom patch is proposed. The conformal antenna consists of three meander lines type unit cells of composite right/left-handed metamaterials for modification and compactness. To improve the operating bandwidth in the first band i.e at 2.45 GHz, a shunt fractal inductor with large inductance is proposed. A similar patch with a slot along the bottom side is additionally used for better impedance matching. The second band at 3.5 GHz is obtained due to the loading of two meander line unit cells on the patch as parasitic elements. The proposed conformal antenna is placed on a 15 mm radius cylinder whose equivalent planar dimension is 0.48λg × 0.36λg (where λg is the guided wavelength). Asymmetrical coplanar waveguide feed is implemented. Measurement results showed that the proposed cylindrical conformal antenna achieves a wideband −10 dB fractional bandwidth of 44.5% and a gain of 1.26 dBi at the operating frequency of 2.45 GHz and 4.5% of bandwidth and a gain of 2.2 dBi at the 3.5 GHz. The radiation efficiency is 70 and 86% at the said frequencies respectively. There is good agreement between measured and simulation data.

Design of high performance narrowband low noise amplifier using on-chip orthogonal series stacked differential fractal inductor for 5G applications

Inductors play a crucial role in the design of radio frequency integrated circuits (RFICs) and they typically consume a considerably large area and have a low-quality factor at high frequencies. The employment of fractal structure in on-chip inductors helps in improving the quality factor and also reduces the overall area besides improving the inductance value. In this paper, an orthogonal series stacked differential fractal inductor is proposed and the same is used to design a low noise amplifier (LNA) for 5G band (27--30 GHz) applications. The proposed inductor is fabricated on a multilayer printed circuit board and the measurement results demonstrate twice the enhancement in inductance, 56 % improvement in quality factor, and 33 % reduction in series resistance when compared to the conventional series stacked fractal inductor for the equivalent on-chip area. The LNA using cascode topology with inductive source degeneration is designed and simulated at a center frequency of 28 GHz in 90 nm CMOS technology using the tool Advanced Design System. The inductors in the LNA are replaced with the proposed on-chip inductor for different layers, which contributes to high gain, better input matching, and low noise figure compared to the state-of-the-art LNAs.

Design of an on-chip Hilbert fractal inductor using an improved feed forward neural network for Si RFICs

Design of an on-chip Hilbert fractal inductor using an improved feed forward neural network for Si RFICs

Fractal series stacked inductor for radio frequency integrated circuit applications

High-quality factor miniaturised inductors are prerequisites of radio frequency integrated circuit applications. This Letter presents a novel fractal stacked inductor using modified Hilbert space filling curve. The proposed inductor achieves higher inductance value and good quality factor because of mutual inductance between plural metal layers and the reduced parasitic resistance. The results show that more than double improvement in L over conventional fractal inductors and more than double improvement in quality factor value over conventional series stack construction.

High inductance fractal inductors for wireless applications

This paper presents fractal-based inductors for industrial, scientific, and medical applications in a frequency range of 3--500 MHz. The proposed inductors are designed based on the Hilbert space-filling curve and omega-shaped space-filling curve. The fractal inductors are designed and simulated by using a full wave high frequency structural simulator. The Hilbert curve-based fractal loop inductor and omega curve-based fractal loop inductor achieve improvements in the inductance value of 21% to 31% and 11% to 30.88%, respectively, over reported standard inductors. The printed inductors are constructed on 3.2 mm RT/Duroid 5770 substrate and measured with a network analyzer (E8363B). It was found that the experimental results are almost in good agreement with the simulation results. It was also observed that the proposed fractal inductors have poor radiating power, indicating no significant electromagnetic radiation.

Fractal inductors on flexible plastic substrate fabricated by laser ablation

In this paper, the feasibility of laser ablated inductors of fractal design on flexible plastic substrate is demonstrated. Inductors are used to store energy during each switching cycle in a switching voltage regulator circuit. Sierpinski fractal inductors of the second and the third iteration were designed, fabricated, and characterized. Two conductive materials, commercially available, were investigated – copper and aluminium adhesive tapes. The inductors are ablated with a current of 28.5A, a frequency of 50kHz and a speed of 1000mm/s in five passes. High frequency parameters as inductance, quality factor, and resistance were analyzed. The inductors were characterized in the frequency range from 10kHz to 1GHz. Copper inductors showed better performances than aluminium inductors.

Koch fractal inductors printed on flexible substrate

Performance analysis of Koch fractal inductors, printed in ink-jet technology, is presented. Koch fractal inductors are printed on a flexible polyimide film in two, three, four and eight layers, using silver nanoparticle ink as the conductor. It was shown that inductors performance improved with increasing the number of conductive layers. In addition, a coreless flexible transformer based on Koch fractal design is presented. The inductance and quality factor of the inductors and transformer windings were measured by impedance analyser in the frequency range from 1 to 250 MHz.

Mitigating Time Interval Error (TIE) in High-Speed Baseband Digital Transports: Design for Delay Compensation at Baseband Infrastructure of Smart-Phones Using Fractal Dispersive Delay-Lines

A major concern in modern smart-phones and hand-held devices is a way of mitigating the time interval error (TIE) perceived at high-speed digital transits along the traces of the circuit-board (rigid and or flexible) used in baseband infrastructures. Indicated here is a way of adopting a planar fractal inductor configuration to improvise the necessary time-delay in the transits of digital signal phase jitter and reduce the TIE. This paper addresses systematic design considerations on fractal inductor geometry commensurate with practical aspects of its implementation as delaylines in the high-speed digital transports at the baseband operations of smart-phone infrastructures. Experimental results obtained from a test module are presented to illustrate the efficacy of the design and acceptable delay performance of the test structure commensurate with the digital transports of interest.