Page 39 - Fall_DTF
P. 39

highly challenging. Alternatively, a micro-LWA achieved Rafa!-ancaa
with a single active element and micromachiried passive  
aperture can enable nitraennic irnaeing in a ernaii Probe that lsongard, E,_Lissek H., and Mosig,1. R. (2010). Acoustic transmission line
. . . . _ rnetarnaterialwitli negative/zero/positiverefmctlve index. PhysimlReview
can acoustically scan and image the iriterlor walls of veins B18 ii943ii6_
and capillaries (Rohde et al., 2017). Caloz, c., and ltoli, T. (2004). Array factor approacli ofleaky-wave antennas
_ _ _ d l' ti t 1-D/2-D '1 ' t/l fl-l1 fl fl (CRLH) st -
Another example m which LWAs offer 21 seme-Chensmg §."re3§£2“i/Zlniare mniefeiliriiilieirrr 176, 274-276. 
technological development is literally out of this world. It Caloz.C.,Itoli,T.,andRennings,A.(2lll)8).CRLlrlnietai-natei-ialleaky-waveand
is for use on future NASA missions to explore liquid worlds ‘e5°"e'“ e“‘e‘‘"“- "355 A"'e""'“ P"7P“§“‘i"" Mflghzihe 5°(5>»15'39-
, . Craster, R. V., and Ciuenneau, S. (2013). Acoustic Mefumtzteritzls. Springer,
such as Saturns largest moon, Titan, and on Europa, one of NewYmie
the moons of IIIl1iier- These moons are believed to Contain Esfalilani, H., Karkar, 5., and Lissek, H. (2015). Exploiting tlie leaky-wave
large subsurface oceans (Europa) or hydrocarbon seas (Titan), properties of transmission-line nietarnaterlals for di-
arid expieratinri or these wnride requires acoustic arrays far gezcégon finding. The Iuumul ujthe Acoustical Sucltty ufAmerim 139, 3259-
‘“°'“ ‘°'“P“‘tl ]i3l"“"’°l3h" “ml 1°“ P°""" ‘hm C“"""*“‘lY Habermana M., and Giiild, M. (2616). Acoustic metamaterials. Phyricr To-
exists. LWAs offer a viable solution to meet these future space day 69(6), 42-48.
gxplorafion nggds_ This would not be the fi_r§( fimg acoustics Haberman, M., and Norris, A. (2016). Acoustic metamaterials. Acoustics
has been used to explore extraterresuial bodies as seisnlic H§'I'l‘::}l,ia1i'V(3>{'\:/n(-l:;994l0) Radiafin Elecfmmtz efic Wave ides US Patent
experiments using arrays of geophones have measured quakes Ne Liiiztgzz; inne i§46_ g g" gu '
on the moon as described by Lynch (2017). Hefner, B. T., and Maisten, P. L. (1999). An aooustical lieljcoidal wave trans-
diicer with applications for the alignnient of iilti-asonic and underwater sys-
Despite these Pmmiehlg f“‘“re ePl7hCeii°ri5 0fLWASa Current tems. ThelllunitllqffheAct7uSfic11lSu£iefy ufAmerim 166, 3313-3315.
research challenges still exist. Due to the ease of fabrication Iacksona D. 11., Caloz,C., and ltoli, T. (20l2).Leaky-wave anteiinas.Prt2eeei1-
and testing as well as implementation of the metamaterial Lf"g‘Ie"«f(‘:l‘: IE? 1”°:i19r‘rl'_fi_2?26ii0Z> D _ r d 1 aky i
. . . _ l|1i ., aoz. .,an o. . . oniinan moee -waveanenna
‘°‘“P°“e“t5v 311 "—"Pe“'“e“‘“l ‘ee1‘“t_‘°“5 °f ‘he “°“_5“‘ witli backfire-to-endfire scanning capability. Electmnics Letters 3s(23),
LWA have been demonstrated in air. Although typical 1414-1416.
structural materials such as plastics and metals have an i—Y"€hi I- (2017)-Aemlsi-i€Send=*5ir°h°"')*Ae""5““ T9410’ 13(3),27-34-
acoustic impedance that is several orders of magnitude larger  
. . . P = - gr 1
than that in air (and therefore tend to appear acoustically ii,3_793_82i_
rigid), these same materials are much closer in impedance Naify, C. 1., Guild, M. D., Rolide, C. A.,Calvo, D. C., and Orris, G. I. (2615).
to water, with significantly more fl“id_e1astic Coupling Demonstration ofa diiectionalsoiliicdpriisniintwo diniensionsusinganair-
As a result, the propagation of sound directly through the   Ex_
WeVeS“|de and ‘he red|e“°n Vie leek)’ e°ml7reS5i°hei Waves Perimental realization ofavariable index transmission line metamaterial as
becomes far more complicated and challenging to control. an acoustic leaky-wave antenna. Applied Physiu Letters 162(4), 203508.
Naify, c. 1., Rogers, 1. 5., Giiild, M. 1)., Rolide, c. A., and orris, G. 1. (2616a).
I.ri addition to the added design challenges for a LWA Evaluation of the resolution of a metamaterial acoustic leaky wave anten-
operating in water, fabrication challenges remain. LWA lift The /""""1l "f ‘he Ae""“"ml Seem)’ ‘fl Amefiffl 139,315!-3258.
designs require high-precision fabrication of unit cells Nmy’ C'l."R°hde’C'A".Mamn.‘ T" P"Gmld'.M' D"md 0m5’GII' gush)"
_ _ Generation of topologically diverse acoustic vonex beams using a coin-
he fehmeted h“'“h'ed5— 0' eVeh th°“5e“d5v °f “mi eel]-5 pact metamaterial apeniire.A,oplied Physiu Letters llls(22),223sll1.
to produce a reliable device. Additive manufacturing Oliner,A. A. and Jackson, D. R., (2607). Leaky-wave antennas. In]. L. Vola-
(3-dimensional printing) offers a promising path forward in klS»A"‘""‘“ E"8l"ee""8 H'"““’°"k- MeG“""H“1-New Yerk
. . . Riaud, A-) Thomas,  L, Claarmn, E., Bussonnlere, A., Matar, O. 13., and
fabricating complex metamaterial structures such as those . . . . . . .
lsaiidoin, M. (2015). Anisotmpic swirling surface acoiistic waves trorn in-
ih e hWA- The “$01118 deVe1°l7ment of new fabrication verse filtering for on-chip generation of acoiistic vonices. Physical Review
techniques and novel metamaterial structures suggest a very App1ied4(3)» 034004-
nrerriieing and exciting future for systems such as the LwA_ Rolide,c.A.,Giiild,M.D.,and Naify, c.1. (Z017).Miniuti4reAmusticLeaky-
Wave Antenna for Ulfrtntmlc Imaging. US Patent Application 15/246,798,
filed March 1, 2017.
Acknowledgments siragiisa, 11., Perret, 13., Lemaitre-Auger, P. Ngiiyn, H. V., Tedjini, 5., and
Portions of this research were carried out at the Jet Propulsion Cfilvzr C-_(l012)-  tapered CR‘-H We‘ ‘“E5"*1/S“'h 1ef*kY'WeVe e'“e"_M
Laboratory, Caljfornialnstitute ofTechnology, underacontract  15::l°be levels‘ IEEE A"m'"'“ “"4 WWI” Pmp”g'm""
With ‘he Ne‘-iehel Aer°m‘“fiC5 and 5Peee Admi“i5m‘fi°h and zweig, (1., l.ipes, 11., and Pierce, 1. R. (1974). Tlie cochlear compromise. me
the support of the Oflice of Naval Research. Iuimiul u] the Acoustical Society ofAmerim 59, 975-982.
Full 201:; | AEBLIIEIEI Tsiiaiiy | 37

   37   38   39   40   41