Mechanism of band gaps in self-similar triangular lattice with Koch fractal

Fractal lattice is a kind of lattices with multifunctional physical characteristics and superior mechanical properties. The wave propagation of the triangular lattice with Koch fractal is calculated by the finite element method and Bloch theorem. The effects of the iteration number on the band gaps and the band edge modes are studied. The finite element software was used to simulate the dynamic response of the triangular lattice with Koch fractal for verifying the vibration suppression performance. The results show that the triangular lattice with Koch fractal can produce multiple and low-frequency band gaps. As an increase of the iteration number, the band gap gradually shifts to a lower frequency. By comparing and analyzing the band edge modes and the eigenmodes of Koch fractal, the mechanisms of the band gaps within the low-frequency ranges are analyzed and discussed in detail. Additionally, the band edge modes exhibit similar vibration modes. Finally, the simulation results of the finite lattice verify the broadband vibration suppression performance of the triangular lattice with Koch fractal. This work provides insights into the lattice dynamic behavior adjusted by Koch fractal, which is beneficial to the periodic lattice for suppressing vibration in engineering applications.

A Novel Metamaterial Inspired 2nd Iteration Koch Fractal Antenna for Wi-Fi, WLAN, C band and X band Wireless Communications

The rapid advancements in wireless technology desires compact, miniaturized, multiband and ultra wideband antennas. Fractal antennas have been proved as a source for fulfilling these demands. In this paper a 2nd order Koch fractal antenna of size 29.6 × 35.7mm2 designed on FR4-epoxy substrate material of dielectric constant (ɛr) 4.4 with a height of 1.6mm. This antenna is named as ANTENNA-1. To increase this antenna’s performance a meta material unit cell has been placed on the ground plane to serve multi band applications and is named as ANTENNA-2, which is the proposed antenna in this paper. The simulations have been carried out for both the antennas using ANSYS HFSS tool over the frequency sweep of (1-12GHz). The simulation results of proposed antenna producing 7 frequency bands which serves Wi-Fi, WLAN, C-band, and X band wireless communications. The simulation results like return loss, VSWR values have a good matching with the measured return loss, VSWR results of the fabricated antenna

Detailed numerical simulation and experimental investigation on micromixers with serpentine Koch fractal microchannels

Micromixer is a kind of microfluidic chip for fast mixing and analysis. Mixing in a micromixer is usually a micron scale. At low Reynolds number, the fluid in the channel is laminar flow, which mainly depends on molecular diffusion as the main mixing mode. Fluid mixing in microchannels is very difficult, especially when the viscosity of the fluid is high. In this paper, we design a novel passive micromixer. The effects of fractal number, Koch fractal channel spacing, microchannel depth and cross-section shape on mixing efficiency were studied. Through a large number of numerical simulations, we continue to optimize the structure of the micromixer and improve the mixing efficiency. Finally, through the continuous optimization of the structure of the micromixer, the mixing efficiency of the micromixer can reach more than 95%.

Modified Koch Fractal Antenna for Multi and Wideband Wireless Applications

This paper focuses on the design and development of modified Koch fractal antenna. Compared to traditional Koch curve antenna, the presented antenna possesses a greater number of frequency bands and better impedance matching. Furthermore, the bacterial foraging optimization (BFO) approach is implemented to enhance the impedance bandwidth. The developed technique has been verified by employing various numerical simulations. The design parameters generated from the optimization procedure have been utilized to manufacture the antenna and the respective experimental and simulated results compared. The measured results show that the designed antenna exhibits multi and wideband behavior, covering WLAN, WIMAX, and various other wireless applications.