Origami-based mechanical metamaterials with tunable frequency band structures (Conference Presentation)

2017 ◽  
Author(s):  
Hiromi Yasuda ◽  
Riley Pratt ◽  
Jinkyu Yang
Keyword(s):  
Frequency Band ◽  
Band Structures ◽  
Mechanical Metamaterials ◽  
Tunable Frequency

DIRAC POINTS, TOPOLOGICAL EDGE MODES AND NONRECIPROCAL TRANSMISSION IN ONE-DIMENSIONAL METAMATERIAL-BASED COUPLED-CAVITY ARRAYS

2013 ◽  
Vol 28 (02) ◽  
pp. 1441006 ◽  
Author(s):  
VASSILIOS YANNOPAPAS
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Band Structure ◽  
Frequency Band ◽  
Negative Phase ◽  
Band Structures ◽  
One Dimensional ◽  
Scattering Spectrum ◽  
Coupled Cavity ◽  
Nonreciprocal Transmission

We show that topological frequency band structures emerge in one-dimensional (1D) electromagnetic (EM) lattices of metamaterial components without the application of an external magnetic field. Such lattices can be cavity arrays coupled with metamaterial elements which generate alternate positive and negative-phase hopping strengths. The topological nature of the band structure manifests itself by the occurrence of Dirac points in the band structure, by the emergence of edge modes in finite arrays as well as by a nonreciprocal scattering spectrum. Specific EM designs for demonstrating the above phenomena are discussed.

scholarly journals A novel 4-DOF wide-range tunable frequency selective surface using an origami “eggbox” structure

2021 ◽  
pp. 1-7
Author(s):  
Yepu Cui ◽  
Ryan Bahr ◽  
Samantha Van Rijs ◽  
Manos Tentzeris
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Frequency Selective Surface ◽  
Ultra Wideband ◽  
Space Applications ◽  
Tunable Range ◽  
Mechanical Metamaterials ◽  
Wide Range ◽  
Frequency Selective ◽  
Tunable Frequency

Abstract Shape-changing mechanical metamaterials have drawn the attention of researchers toward the development of continuous-range tunable frequency selective surfaces (FSSs). In this paper, a novel tunable FSS utilizing an origami-inspired “eggbox” structure is presented featuring four-degrees of freedom that can change the frequency response of two orthogonal linear polarizations. The centrosymmetric “eggbox” structure can be folded or rotated along two axes that lead to unprecedented reconfigurability compared to traditional Miura-Ori-based structures which have fewer degrees of control. The utilized cross-shaped dipole FSS element shows enhanced bandwidth, support for orthogonal linear polarization, and ease of fabrication. The prototype is fabricated using a low-cost fully additive inkjet printing process with silver nanoparticle conductive ink. The outcome of this study shows a 25% frequency tunable range over two polarization directions. The design can be an ideal spatial filtering candidate for advanced ultra-wideband terrestrial and space applications.

Tunable Wave Dynamics in Origami-Based Mechanical Metamaterials

2016 ◽  
Author(s):  
Hiromi Yasuda ◽  
Mia Lee ◽  
Jinkyu Yang
Keyword(s):  
Geometrical Parameters ◽  
Wave Dynamics ◽  
Mechanical Metamaterials ◽  
Mechanical Waves ◽  
1D Chain ◽  
Unit Cells ◽  
A Chain ◽  
Tunable Frequency ◽  
Relationship Of ◽  
The Given

We investigate unique wave dynamics in origami-based mechanical metamaterials composed of volumetric 3D origami unit cells. Specifically, we assemble a chain of lattice structures, in which the Tachi-Miura Polyhedron (TMP) is employed as a building block. We conduct two types of theoretical/computational analysis on this origami-based system. One is the dynamic analysis on the TMP unit cell under harmonic excitations. We find that the system transits from linear to nonlinear regimes or vice versa, depending on the amplitude of the excitation and the initial configurations of the given geometry. This implies that the origami-based system exhibits intrinsic tun-ability of its dynamic behavior by altering these excitation and geometrical parameters. The other analysis is on a dispersion relationship of mechanical waves propagating through the lattice. We analyze a 1D chain of (i) all identical TMP unit cells and (ii) two different unit cells in an alternating arrangement. From this analysis, we show that the origami-based system can create tunable frequency band structures by changing geometrical parameters. By leveraging these unique, tunable wave dynamics, the origami-based mechanical systems have great potential to be used as novel engineering devices that are capable of handling vibrations and impact efficiently.

scholarly journals Numerical Study of Extremely Wideband-Modified Biconical Radiation Structures for Electronic Support Measures Application

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 369
Author(s):  
Chen Wu ◽  
Janaka Elangage
Keyword(s):  
Frequency Band ◽  
Numerical Study ◽  
Characteristic Impedance ◽  
Coaxial Line ◽  
Frequency Bands ◽  
Metallic Ring ◽  
Metallic Rings ◽  
Tunable Frequency ◽  
Electronic Support ◽  
Difference Time

Using the finite difference time domain (FD-TD) method, this paper studies radiation structures that can have multiple tunable frequency bands between 0.4 GHz and 4 GHz, a fixed band in [3.97, 5.36] GHz and an extremely wideband from 6.14 GHz to 68.27 GHz, where a frequency band is defined by the voltage standing wave ratio (VSWR) less than or equal to two. The base radiation structure has a modified-biconical antenna configuration, called base MBA, and is fed by a square-coaxial line with characteristic impedance close to 50 ohms. A dielectric ring and an outer dielectric cover are used between the two modified cones to enlarge the frequency band and strengthen the structure. An equal number of metallic-rings can be stacked at both circular-ends of cones in the base MBA to tune the positions of the frequency bands that are lower than 4 GHz and to alter their vertical polarization (V-pol) patterns. However, compared with those of the base MBA, these stacked metallic rings do not make significant changes to the VSWR in the [3.97, 5.36] GHz and [6.14, 28.27] GHz bands and the radiation patterns in the [6.14, 28.27] GHz band. The simulation results show that the base MBA and its metallic-ring-loaded versions all have V-pol radiation characteristics at all frequency bands and have donut-shaped omnidirectional patterns only when the wavelength is bigger than the length of the structure. When the wavelength is less than the size of the radiation structure, the donut shape is modified with ripples on the V-pol radiation pattern. Sometimes deep notches could be observed when MBAs operated at the higher end of the extremely wideband. A 0.2 mm cube was used to construct the antenna structures with the consideration of using the 3D metal/dielectric printer technology to build the antennas in the future.

Basilar membrane-inspired self-powered acoustic sensor enabled by highly sensitive multi tunable frequency band

Nano Energy ◽  
2018 ◽  
Vol 53 ◽  
pp. 198-205 ◽  
Author(s):  
Jae Hyun Han ◽  
Jun-Hyuk Kwak ◽  
Daniel Juhyung Joe ◽  
Seong Kwang Hong ◽  
Hee Seung Wang ◽  
...  
Keyword(s):  
Frequency Band ◽  
Basilar Membrane ◽  
Acoustic Sensor ◽  
Highly Sensitive ◽  
Self Powered ◽  
Tunable Frequency

Tunable frequency bandgaps in elastic metamaterials with internal contacts

2021 ◽  
Vol 263 (4) ◽  
pp. 2522-2525
Author(s):  
Eunho Kim ◽  
Guenil Kim ◽  
Kyeong Min Cho ◽  
Yeongtae Jang
Keyword(s):  
Band Structure ◽  
Frequency Band ◽  
Cell Structure ◽  
Sudden Change ◽  
Frequency Characteristics ◽  
Unit Cell ◽  
3D Printer ◽  
Elastic Metamaterials ◽  
Tunable Frequency ◽  
Unit Cell Structure

We design an elastic metamaterial with internal contacts and study the tunable frequency band structure of the metamaterial. It is well-known that the frequency band of granule structures consisting of particles changes depending on the system's compression because of the nonlinearity of the contact between particles. We adopt this efficient tunning mechanism, i.e., contact, in the design of continuum type elastic metamaterials. We first design a unit cell structure showing internal contacts under compression and fabricate it using a 3D printer. We numerically and experimentally identify that the unit cell's stiffness suddenly increases when the internal contact happens. This sudden change of the stiffness induces a change of frequency characteristics of the structure. Here, we demonstrate that internal contacts are useful for designing various frequency bandgaps and tuning them efficiently.

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