G aphene-based
beam- econfigu able liquid
an enna o 5G mmWa e wi eless
sys ems
Sasmi a Dash*, Cons an inos Psomas and Ioannis K ikidis
Depa men o Elec ical and Compu e Enginee ing, Uni e si y o Cyp us, Nicosia, Cyp us
The ad ancemen o wi eless echnologies has led o significan p og ess in
an enna design in o de o mee he con inuously inc easing demands. Liquid
an ennas ha e gained significan in e es in esea ch owing o hei dis inc i e
p ope ies, such as being small, flexible, anspa en , and capable o
econfigu a ion. Recen ly, g aphene liquid has been conside ed o a ious
applica ions because o i s a o dabili y, excellen conduc i i y, flexibili y,
anspa ency, and easy p ocessing. This pape p esen s a beam- econfigu able
g aphene liquid an enna. The mo emen o he g aphene liquid wi hin he
mic ofluidic channel enables beam econfigu a ion. The an enna is ealized in
a ec angula mic ofluidic channel made o polyme hyl me hac yla e o e a liquid
c ys al polyme subs a e. The p oposed an enna pe o ms beam-s ee ing up o
360°wi h 7 dBi o gain and ope a es a 28 GHz wi h a wideband o 10-dB
impedance bandwid h o o e 20%. In pa icula , he main beam o he an enna
econfigu es in o six di ec ions (0°,45°,135°,180°,225°and 315°)a he ope a ing
equency. Mo eo e , he an enna o e s a consis en eflec ion coe ficien a
28 GHz in each o he six econfigu able equencies. The e o e, he p oposed
no el echnique o designing econfigu able an ennas using g aphene liquid
holds g ea p omise o 5G mmWa e wi eless communica ion sys ems.
KEYWORDS
g aphene liquid, mic ofluidic, an enna, mmwa e, beam econfigu a ion, wi eless
communica ions
1 In oduc ion
O e he pas ew yea s, wi eless communica ion sys ems ha e unde gone significan
e olu iona y ad ancemen s. Fi h-gene a ion (5G) wi eless communica ions ne wo ks
ha e al eady been deployed wi h he aim o p o iding high da a a es (Chowdhu y
e al., 2020). In pa icula , 5G has been o mally comme cialized since 2019, using he
millime e wa e (mmWa e) and sub-6 GHz bands. Howe e , he apid g ow h in he
numbe o sma de ices and he eme gence o he In e ne o E e y hing (IoE) applica ions,
which equi e ene gy-e ficien , ul a- eliable and low-la ency communica ions, will
subs an ially bu den he 5G wi eless ne wo ks (Alsabah e al., 2021;Chowdhu y e al.,
2020). The e o e, he 5G pa adigm will be u he de eloped and expanded unde six h-
gene a ion (6G) echnologies ha will pu sue wide co e age, highe a es, mo e
connec ions, ul a-low la ency, ul a-high posi ioning accu acy, in eg a ion o
communica ions and sensing, mo e in elligence, mo e secu i y, and be e
subs i u abili y (Chowdhu y e al., 2020). The mmWa e communica ion sys ems o e
OPEN ACCESS
EDITED BY
Muhammad Ik am,
King Abdullah Uni e si y o Science and
Technology, Saudi A abia
REVIEWED BY
Ahmad Bazzi,
New Yo k Uni e si y Abu Dhabi, Uni ed A ab
Emi a es
Ruiqi Wang,
King Abdullah Uni e si y o Science and
Technology, Saudi A abia
*CORRESPONDENCE
Sasmi a Dash,
[email p o ec ed]
RECEIVED 14 Janua y 2025
ACCEPTED 12 Ma ch 2025
PUBLISHED 21 Ma ch 2025
CITATION
Dash S, Psomas C and K ikidis I (2025)
G aphene-based beam- econfigu able liquid
an enna o 5G mmWa e wi eless sys ems.
F on . Commun. Ne w. 6:1560311.
doi: 10.3389/ cmn.2025.1560311
COPYRIGHT
© 2025 Dash, Psomas and K ikidis. This is an
open-access a icle dis ibu ed unde he e ms
o he C ea i e Commons A ibu ion License
(CC BY). The use, dis ibu ion o ep oduc ion in
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c edi ed and ha he o iginal publica ion in his
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F on ie s in Communica ions and Ne wo ks on ie sin.o g01
TYPE O iginal Resea ch
PUBLISHED 21 Ma ch 2025
DOI 10.3389/ cmn.2025.1560311
significan ad an ages in e ms o high da a a es and bandwid h,
spec um a ailabili y, beam o ming capabili ies, high spa ial
esolu ion, and educed la ency, making hem essen ial o he
5G wi eless communica ion ne wo ks (Hong e al., 2021).
Howe e , wi eless communica ions o e he mmWa e bands a e
suscep ible by bad wea he condi ions and obs acles due o he
signal’s smalle wa eleng hs. The e o e, e ficien an ennas ha
o e come hese limi a ions a e impo an o he e ec i e
ope a ion o u u e wi eless sys ems.
In he p esen e a o wi eless communica ion sys ems,
adap abili y and di e se unc ionali y s and ou as he mos
a ac i e ea u es in any communica ion de ice. The e o e, since
he an enna is essen ial o hese sys ems, he apid p og ession
owa ds 5G echnologies necessi a es he design o e ficien
an ennas. Ne e heless, con en ional an ennas, usually made o
conduc i e me als on s i subs a es, pe o m well bu a e no
mechanically flexible. Mo eo e , exceeding ce ain limi s in
bending o s e ching hese an ennas leads o i e e sible
s uc u al de o ma ions and e en des uc ion (Alzoubi e al.,
2011). As a consequence, me allic an ennas’ igidi y limi s hei
use in applica ion whe e flexibili y is equi ed. This mo i a es he
need o mo e flexible and adap able an ennas, such as an ennas
using me allic liquids (Huang e al., 2021). Me allic liquids a e a
pe ec subs i u e o flexible an enna applica ions due o hei
flowing p ope ies and lack o de o ma ion limi s. Mo eo e ,
liquid me als in mic ofluidic channels main ain excep ional
flexibili y and mechanical s abili y wi hou comp omising hei
elec ical p ope ies (So e al., 2009). The e o e, me allic liquid
an ennas a e pe ec o an enna applica ions because o hei
excep ional flexibili y, de o mabili y, and high conduc i i y.
Mode n me hods o ab ica ing an ennas ake ad an age o he
fluidic quali ies o me allic liquids, such as 3D p in ing, injec ing, o
sp aying me allic liquid on o igid o flexible subs a es. Liquid
an ennas can eadily achie e econfigu abili y h ough
elec ochemically con olled capilla y ac ion o mic o pumping,
in con as o adi ional echniques like high- equency
swi ching. Gi en hese impo an benefi s, he e has been
significan in e es ecen ly on he beneficial ole o liquid
an ennas in wi eless communica ion sys ems (Psomas e al.,
2023;Wong e al., 2021). The basis o de eloping e ficien liquid
an ennas is ound in he special quali ies o liquid ma e ials, which
ha e a majo impac on an enna pe o mance and design.
Liquid an ennas capi alize on he mechanical p ope ies o
fluids, le e aging hei abili y o change shape and flow o c ea e
flexible, econfigu able, and adap able an enna s uc u es o a ious
applica ions (Huang e al., 2021). The p esence o me allic liquid in
fluidic channels allows he fluidic channel o ake shape due o i s
low iscosi y (Choi, 2014). Flexible subs a es allow o he bending,
olding, s e ching, and wis ing o liquid an ennas, he eby
wi hs anding a ious o ms o mechanical de o ma ion. Howe e ,
due o hei high deg ee o e e sibili y, hey can ins an ly egain
hei o iginal o m (So e al., 2009). Because o hei in insic
flexibili y, liquid ma e ials se e as a iable subs i u e o igid o
solid conduc o s in he ealm o flexible elec onics (Va na a, 2019).
The de elopmen o me allic liquid an ennas is made possible by he
fluidic p ope ies o me allic liquids. By using me allic liquids as
adia i e elemen s ins ead o solid conduc o s like coppe , i is
possible o c ea e an ennas ha a e much mo e flexible and
econfigu able. Mo eo e , he high conduc i i y inhe en in
me allic liquids makes hem pa icula ly well-sui ed o an enna
applica ions. Indeed, he fluidic p ope ies o me allic liquids ha e
enabled a wide ange o me allic liquid an ennas (Kos a and
ChaIu edi, 1989;Dey e al., 2016;Hayes e al., 2012;So e al.
2009;Mo ishi a e al., 2013). E en when adia i e elemen s a e
ins alled on igid subs a es, mo e flexibili y and econfigu abili y
can be achie ed due o he fluidic na u e o liquid ma e ials. Me allic
liquids ha e been used o de elop flexible and econfigu able
an ennas since he la e 80s (Kos a and ChaIu edi, 1989). One
no able example o a me allic liquid is me cu y (Hg). The fluidic and
conduc i e na u e o me cu y allows o he design o econfigu able
me allic liquid an ennas (Dey e al., 2016). Howe e , he oxic na u e
and high cos o me cu y impose limi a ions on i s use o an ennas.
Al e na i e me allic liquid ma e ials ypically mani es as alloys
composed o conduc i e nanopa icles. A well-known alloy o
liquid an enna consis s o gallium and indium has been explo ed
in se e al an enna designs (Hayes e al., 2012;So e al., 2009;
Mo ishi a e al., 2013).
Recen ly, me allic liquid an ennas employing g aphene liquid, a
no el me allic liquid ma e ial, ha e been designed (Dash e al.,
2023). In compa ison o adi ional me allic liquid an ennas made o
me cu y and gallium indium alloy (EGaIn), g aphene-based liquid
an ennas exhibi supe io elec omagne ic pe o mance. Since i s
disco e y in 2004 No oselo e al. (2004), he supe io p ope ies o
g aphene, including high elec ical conduc i i y (= ~106), high
mechanical ensile s eng h (= ~130 GPa) and high he mal
conduc i i y (= ~5000 W/m.K), ha e led o a g ea deal o
cu en esea ch in e es and a wide ange o p ac ical
applica ions. G aphene-based me asu ace designs ha e ga ne ed
significan esea ch in e es in ecen yea s (Dho e e al., 2023;
Mole o e al., 2021). Reconfigu able in elligen su aces based on
me ama e ials open new possibili ies o u u e sensing and wi eless
communica ion sys ems (Wang e al., 2024;Bazzi and Chafii, 2025).
Due o he high elec on mobili y wi hin he hexagonally a anged
ca bon a oms o g aphene, i exhibi s an elec ical conduc i i y o
he o de o 106S/m (S u i and Jagannadham, 2010). Hence, he
conduc i i y o he g aphene liquid is su ficien o i s use as an
an enna candida e, ensu ing high e ficiency. Mo eo e , since
g aphene does no mel when hea ed, i lacks a defined mel ing
poin . Ins ead, i unde goes sublima ion a empe a u es a ound
3,600 K.
Table 1 p esen s he ma e ial p ope ies o g aphene liquid in
compa ison o con en ional me allic liquids such as me cu y and
EGaIn. The compa ison highligh s ha g aphene liquid is a
p omising candida e o liquid an ennas, o e ing ad an ages o e
adi ional me allic liquids. G aphene’s highe elec ical
conduc i i y and op ical anspa ency p o ide significan
ad an ages o e EGaIn, pa icula ly in applica ions whe e bo h
high conduc i i y and op ical anspa ency a e equi ed.
G aphene’s highe conduc i i y makes i ideal o ul a- as
elec onics, flexible ci cui s, and an ennas. G aphene is nea ly
anspa en , abso bing only 2.3% o isible ligh , making i an
excellen ma e ial o anspa en conduc i e films, ouchsc eens,
and op oelec onic de ices. EGaIn is comple ely opaque, limi ing i s
use in applica ions equi ing op ical anspa ency. Mo eo e ,
g aphene liquid p o es o be sa e o indus ial use and is
en i onmen ally iendly. As a esul , g aphene liquid has many
F on ie s in Communica ions and Ne wo ks on ie sin.o g02
Dash e al. 10.3389/ cmn.2025.1560311
applica ions in a ious indus ies (Ma linda e al., 2023). The
ex ensi e esea ch ocus in ecen yea s has led o he u iliza ion
o g aphene inks o flexible elec onics, wi eless connec i i y, and
In e ne o Things (IoT) applica ions (Yang and Wang, 2016;Pan
e al., 2018). In addi ion o i s flexibili y, he s abili y and
biocompa ibili y o g aphene ha e gained in e es as a p omising
candida e o applica ions in neu oscience, ca diac science, and
biomedical enginee ing (Ga cia-Co adella e al., 2021;Gao e al.,
2024). The e o e, i is no su p ise ha , du ing he las decade,
g aphene has been p o en o be a well-known ma e ial o
e ficien an enna design (Dash e al., 2020;Dash and Pa naik,
2021). Ne e heless, designs o g aphene-based liquid an ennas
emain unexplo ed. To he au ho s’knowledge, g aphene
conduc i e liquid o beam econfigu able an enna is conside ed
in his wo k o he fi s ime. Compa ed o con en ional me allic
liquid an ennas ha use me cu y and EGaIn, g aphene liquid
an enna pe o ms be e in e ms o gain, bandwid h, eflec ion
coe ficien , as well as adia ion e ficiency (Dash e al., 2023).
Addi ionally, i o e s econfigu abili y and he po en ial o
in eg a ion in o ad anced communica ion sys ems. These
ad an ages make i a compelling al e na i e, pa icula ly o
applica ions equi ing flexibili y and dynamic econfigu a ion. In
his wo k, we in oduce a new me hod o designing a beam-
econfigu able an enna ha uses g aphene liquid inside a
mic ofluidic channel. The a ious s a es and econfigu a ions o
he p oposed liquid an enna a e made possible by he fluidic
p ope y o he g aphene liquid. In he p esen wo k, he main
beam is econfigu ed in di e en di ec ions by mo ing he g aphene
liquid o di e en loca ions. The mo emen o he g aphene liquid
wi hin he mic ofluidic channel is used o in es iga e a
econfigu a ion mechanism o he an enna beams. The an enna
is ealized in a ec angula -shaped poly me hyl me hac yla e
mic ofluidic channel o e a liquid c ys al polyme subs a e. The
p ima y con ibu ions o he pape a e p o ided below:
•A mic ofluidically beam- econfigu able an enna based on
g aphene liquid o mmWa e communica ion sys ems is
p oposed. The an enna design concep u ilizes he unique
p ope ies o he g aphene liquid and uses i s mo emen inside
he mic ofluidic channel in o de o p o ide he new deg ee o
pe o mance in he liquid an enna sys ems. The p oposed
g aphene-based liquid an enna is ealized in a ec angula poly
me hyl me hac yla e mic ofluidic channel o e a liquid c ys al
polyme subs a e.
•We design and nume ically analyze he mic ofluidically
g aphene-based beam- econfigu able liquid an enna o
mmWa e sys ems by using he fini e elemen me hod
(FEM)-based elec omagne ic (EM) simula o .
•The pe o mance o he p oposed an enna is in es iga ed by
conside ing he mo emen o he g aphene liquid inside he
mic ofluidic channel and he cha ac e is ics o he liquid a
di e en loca ions inside he mic ofluidic channel. I is
demons a ed ha he an enna’s adia ion di ec ion is
econfigu able, co e ing up o 360°angle wi h six beams a
an ope a ional equency o 28 GHz.
•Finally, we in es iga e he pe o mance o he p oposed
g aphene-based liquid an enna in e ms o gain, e ficiency,
bandwid h, econfigu abili y, design flexibili y and sa e y.
2 Design and analysis o beam
econfigu able g aphene-
liquid an enna
2.1 An enna design
We design and nume ically analyze he p oposed g aphene-
based liquid an enna o e mmWa e equency bands. The an enna
consis s he g aphene liquid (≈1 ml olume) in a ec angula -
shaped poly me hyl me hac yla e mic ofluidic channel (leng h Lc =
13.74 mm, wid h Wc = 9.12 mm, and diame e Dc = 0.75 mm) and
placed o e a me allic g ounded liquid c ys al polyme subs a e o
dimension (17.4×12.4×1)mm3. Pla inum me al is aken in o
conside a ion as he g ound plane o he p oposed an enna
s uc u e. A polyme hyl me hac yla e mic ofluidic channel o e a
liquid c ys al polyme subs a e is a p omising solu ion o educing
g aphene liquid pocke o ma ion. I p o ides flow con ol,
imp o es adhesion, and enhances uni o mi y. A polyme hyl
me hac yla e mic ofluidic s uc u e p o ides a confined flow pa h
o g aphene liquid, ensu ing consis en sp eading and educed oid
o ma ion. By con olling flow dynamics (e.g., ia capilla y ac ion o
mic opumps), he g aphene liquid can be e enly dis ibu ed,
minimizing unp edic able pocke o ma ion. The liquid c ys al
polyme subs a e is flexible, chemically s able, and has low
su ace oughness, making i a sui able base o uni o m
g aphene deposi ion. Unlike igid subs a es like silicon, he
liquid c ys al polyme subs a e can con o m o mic ofluidic
s uc u es, educing unwan ed gaps o ai pocke s. The
TABLE 1 Ma e ial p ope ies o g aphene compa ed o o he con en ional me allic liquid.
Pa ame e G aphnee Me cu y EGaIn
Elec ical Conduc i i y 50 × 106(S/m) 1 × 106(S/m) 3.4×10
6(S/m)
The mal Conduc i i y ~5000 W/m ·K~8W/m·K ~50 W/m ·K
Mel ing Tempe a u e Does no mel (sublimes a 3,600 K) −38.87°C16
°C
Densi y ~2000 kg/m3~6000 kg/m3~13000 kg/m3
Viscosi y 1 −1000 mPa ·s~1.5 mPa ·s ~2 mPa ·s
Op ical T anspa ency highly anspa en ~97%Comple ely opaque Nea - o al opaci y
The mal s abili y High up o ~3000°C Low Mode a e
F on ie s in Communica ions and Ne wo ks on ie sin.o g03
Dash e al. 10.3389/ cmn.2025.1560311
polyme hyl me hac yla e can ac as an in e ace laye be ween
g aphene liquid and liquid c ys al polyme subs a e, imp o ing
su ace we abili y and adhesion. Mo eo e , he liquid c ys al
polyme subs a e has low mois u e abso p ion and good
dielec ic p ope ies, making i ideal o g aphene liquid an enna
applica ions.
Figu e 1 illus a e he p oposed mic ofluidically g aphene-based
liquid an enna. The dimensions o he an enna a e op imized o he
ope a ing equency o 28 GHz. Table 2 displays he geome ical
dimensions o an enna. The p oposed an enna is designed, analyzed
and i s pe o mance is alida ed using he FEM-based Anso HFSS
so wa e by ANSYS HFSS (2021). The cen e - ed single p obe
me hod is used o exci e he an enna. The an enna’s g ound
plane (bo om laye ) is a me al shee ha is elec ically connec ed
o an SMA connec o ’s ex e nal conduc o . The eeding p obe is
elec ically connec ed o he SMA’s in e nal conduc o and inse s
in o he me allic liquid om i s bo om cen e . In six loca ions P1,
P2, P3, P4, P5, and P6, six SMA connec o s a e connec ed. The
olume o liquid has a ole in he equency econfigu a ion o he
an enna and he adia ion pa e n is econfigu ed by he mo emen
o liquid a di e en loca ions wi hin he mic ofluidic channel. In
o de o achie e an enna beam econfigu abili y, he posi ion o he
g aphene liquid eloca es in o di e en posi ions in he
mic ofluidic channel.
Since his g aphene liquid an enna is exci ed by only one po a
a ime, he an enna e alua es only S11 o he ac i e po . The
S11 pa ame e has been e alua ed o e u n loss analysis, ensu ing
ha eflec ion a he exci ed po is minimized o e ficien adia ion
a he desi ed equencies. S12 ypically ep esen s ansmission
be ween wo simul aneously ac i e po s, which does no apply in
his case because, a any gi en ime, only one po is exci ed.
Howe e , when he g aphene liquid mo es and shi s exci a ion
o a second po , a new S11 measu emen is pe o med o ha
configu a ion. This means ha each s a e o he an enna has i s own
S11 e alua ion, bu no di ec S12 measu emen exis s. In his design,
whe e a single po is ac i e a any ime, he essen ial pe o mance
me ics include: S11 o impedance ma ching a each exci a ion
s a e, adia ion pa e ns o analyze beam s ee ing e ec i eness, gain
and e ficiency o e alua e an enna pe o mance.
2.2 EM simula ion
The Ansys HFSS, an FEM-based elec omagne ic (EM) sol e , is
used o alida e he p oposed designed g aphene-based liquid
an enna wi h a esonan equency o 28 GHz ANSYS HFSS
(2021). The an enna is ealized by conside ing a fixed olume
(≈1 ml) o g aphene liquid in o a poly me hyl me hac yla e
mic ofluidic channel (leng h Lc = 13.74 mm, wid h Wc =
9.12 mm, and diame e Dc = 0.75 mm) o e a me allic g ounded
liquid c ys al polyme subs a e o dimensions (17.39 × 12.40 × 1)
mm3. The pla inum me al is used as a g ound plane o he p oposed
an enna s uc u e. The g ound plane o he p oposed an enna is
made o pla inum me al. The an enna s uc u es’dimensions and
g aphene liquid olume a e op imized o he 28 GHz
ope a ing equency.
Fo he modelling o he g aphene liquid in he FEM-based EM
sol e , i is essen ial o model he conduc i e liquid wi h he su ace
conduc i i y σs(Equa ion 1) o g aphene in he ope a ional
equency 28 GHz acco ding o Kubo o malism Gusynin e al.
(2006). In he EM simula o , he g aphene liquid is hus ep esen ed
as a conduc i e liquid wi h a su ace conduc i i y σs.
σs−je2KBT
πZ2ω−jτ−1
μc
KBT+2 ln exp −μc
KBT
+1
,(1)
whe e KBs ands o Bol zmann’s cons an , Z o educed Planck’s
cons an , T o empe a u e, μc o chemical po en ial, τ o
elaxa ion ime, ω o angula equency, e o elec onic cha ge,
and j o imagina y uni .
The g aphene liquid flows in he mic ofluidic channel om one
posi ion o ano he . In he p esen wo k, six posi ions o g aphene
liquid in he mic ofluidic channel a e conside ed. The cen e - ed
single p obe me hod is used o exci e he an enna. The an enna is
FIGURE 1
Schema ic o he p oposed g aphene-based liquid an enna. (a)
3D iew. (b) C oss-sec ional iew.
TABLE 2 The geome ical dimensions o he p oposed liquid an enna.
Ls (mm) Ws (mm) Lc (mm) Wc (mm) Dc (mm) Lm (mm)
17.39 12.40 13.74 9.12 0.75 3
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Dash e al. 10.3389/ cmn.2025.1560311
exci ed a he cen e o g aphene liquid adia ing elemen s, like
dipoles. In o de o eed he g aphene liquid an enna in a
mic ofluidic channel, he ex e nal conduc o o he SMA
connec o connec ed o he g ound plane. The eeding p obe is
elec ically connec ed o he inne conduc o o he SMA and
inse ed in o he g aphene liquid om he bo om cen e , as
shown in Figu e 1b. To a ain six wo king modes and beam
econfigu abili y, six eeding po s a e c ea ed in six posi ions.
Impedance ma ching mus be accomplished in o de o gua an ee
he an enna’s maximum adia ion. Figu e 3 illus a es he beha io
o an enna impedance ma ching. I is e iden ha o each o he six
g aphene liquid posi ions, he an enna has a well-ma ched esonan
equency a 28 GHz.
2.3 Fab ica ion easibili y
The ab ica ion easibili y o he p oposed g aphene-based liquid
an enna can be explained using Figu e 2. The g aphene liquid
an enna can be mechanically suppo ed by a silicon wa e
sample. The g aphene-based liquid an enna can be ealized by
injec ing g aphene liquid in o a poly me hyl me hac yla e
mic ofluidic channel (ϵ 2.55, an δ0.002) o e a me allic
g ounded liquid c ys al polyme subs a e (ϵ 2.9, an
δ0.0025) (Ling e al., 2015;Dey e al., 2016). The so
li hog aphic p ocesses can be used o ab ica e mic ofluidic
channel (Xia and Whi esides, 1998;So e al., 2009;Dey e al.,
2016). The mic ofluidic channel o poly me hyl me hac yla e
elas ome can be sealed wi h a hin and fla shee o liquid
c ys al polyme based subs a e laye (Dey e al., 2016;Rod igo
e al., 2012). The g aphene liquid can fi s be injec ed using a sy inge
in o he polyme hyl me hac yla e channel o fill he mic ofluidic ha
defines he adia ing elemen . The mic opump uni will econfigu e
he liquid olume o he an enna in he mic ofluidic channel. Du ing
he p ac ical ealiza ion o he g aphene liquid an enna, six SMA
connec o s in six loca ions P1, P2, P3, P4, P5, and P6 can be
employed. Six eeding po s can be c ea ed in six posi ions o
a ain six wo king modes and beam econfigu abili y. The
g aphene liquid flows in he mic ofluidic channel om one
posi ion o ano he . Wi h he use o a mic opump con olle
h ough mic ofluidic echniques, he loca ion o he g aphene
liquid wi hin he mic ofluidic channel can be adjus ed o achie e
he in ended ou come. The main beam o an enna is econfigu ed
when he g aphene liquid is displaced om one posi ion o ano he .
Physical displacemen o he g aphene liquid can be achie ed
h ough mic ofluidic echniques like pumping o elec owe ing
(Rod igo e al., 2012). Digi al mic ofluidics is also a new
conside a ion o he physical displacemen o me allic liquid in
mic ofluidic channel (Wan e al., 2006).
Reconfigu abili y is one o he impo an ad an ages o he
p oposed g aphene-based liquid an enna. The an enna’s
ope a ing equency can be uned by a ying he olume and
shape o he g aphene liquid. The olume o liquid has a ole in
he equency econfigu a ion o he an enna and he adia ion
pa e n is econfigu ed by he mo emen o liquid a a ious
posi ions wi hin he mic ofluidic channel. By u ilizing he
mic opump uni o al e he g aphene liquid configu a ion inside
he mic ofluidic channel, he an enna achie es beam
econfigu abili y.
2.4 Resul analysis
The eflec ion coe ficien o he mic ofluidically g aphene-based
liquid an enna a six di e en posi ions P1, P2, P3, P4, P5 and P6 a e
shown in Figu e 3. I can be no iced ha he p oposed an enna
esona es a 28 GHz in six di e en posi ions P1, P2, P3, P4, P5 and
P6. The an enna esonan equency emains he same o all six
posi ions in he mic ofluidic channel. The an enna o e s a wideband
o 10-dB impedance bandwid h o 22%. Consequen ly, six dis inc
ope a ion s a es a e made possible by he fluidic p ope y o he
g aphene liquid in he mic ofluidic channel. The loss cha ac e is ics
o he g aphene liquid in he conside ed ope a ional equency
bands can be u he no iced in Figu e 3. The g aphene liquid
an enna exhibi s low losses a 28 GHz equency. These an enna
losses a e significan ly influenced by he conduc i i y o he ma e ial.
The e o e, due o i s high conduc i i y, he g aphene liquid an enna
has a low loss.
FIGURE 2
The ab ica ion easibili y o he p oposed g aphene-based liquid an enna.
F on ie s in Communica ions and Ne wo ks on ie sin.o g05
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The olume o he g aphene liquid in a mic ofluidic channel
plays a significan ole in ope a ing a di e en equencies. Figu e 4
shows he eflec ion coe ficien o an enna a di e en liquid
olumes o illus a e how he liquid olume a ec s he an enna
pe o mance. The eflec ion pe o mance o he g aphene liquid
an enna is analyzed o di e en olumes, wi h Lm a ying be ween
2 mm and 5 mm. The an enna ope a es a di e en equencies
be ween 24 GHz and 30 GHz by a ying he olume o he liquid in
he mic ofluidic channel om Lm = 2 mm–5 mm, which is clea ly
ma ked in Figu e 4. Fu he mo e, i can be no iced ha an an enna
wi h a smalle liquid olume leads o highe ope a ional equency,
whe eas an an enna wi h a highe liquid olume ope a es a a lowe
equency. The an enna esona es a 30 GHz, 28 GHz, 26 GHz, and
24 GHz when Lm = 2 mm, 3 mm, 4 mm and 5 mm a e conside ed,
espec i ely. The esonan equency dec eases wi h he olume o
liquid and can be dynamically con olled in a wide equency ange.
The p oposed g aphene-based liquid an enna a 28 GHz a ains
a unidi ec ional symme ical adia ion pa e n wi h a gain o 7 dBi,
as illus a ed in Figu e 5. The an enna’s gain and adia ion e ficiency
o e he equency bands 10–45 GHz a e shown in Figu e 6. O e
he conside ed equency bands, he an enna’s adia ion e ficiency
exceeds 60%. Figu e 8 shows he no malized adia ion pa e ns o
he p oposed g aphene liquid an enna a 28 GHz. The p oposed
an enna p o ides a educed back lobe adia ion wi h on - o-back
a io o 10 dB, which can be obse ed in Figu e 8. Beam
econfigu a ion and six di e en ope a ion s a es a e made
possible by he flow o he g aphene liquid in o six dis inc
loca ions wi hin he mic ofluidic channel. The p oposed
g aphene-based liquid an enna wi h six beams is p esen ed in
Figu e 7. The an enna’s no malized adia ion pa e ns in six
modes a e shown in Figu e 8. By app op ia ely choosing he
loca ion o he g aphene liquid wi hin he mic ofluidic channel,
he an enna can be di ec ed in D2 (θ0°),D3(θ45°),
D4 (θ135°),D5(θ180°),D6(θ225°), and D1 (θ315°)
di ec ions. A an ope a ional equency 28 GHz, he an enna
econfigu es he main beam di ec ion, co e ing a 360°angle.
Table 3 lis s he an enna main beam di ec ions o each g aphene
liquid loca ions. The 3D pa e n shows he highly di ec ional beam.
The beam wid h appea s wide when he adia ion pa e n is
no malized and plo ed in 2D (Figu e 8). This di e ence a ises
due o no maliza ion e ec s and scaling in 2D plo s. In 2D
no malized adia ion plo s, powe le els a e scaled ela i e o he
peak. The no malized adia ion plo does no eflec absolu e gain,
only he ela i e powe dis ibu ion. The p oposed an enna p o ides
<40°HPBW (hal powe beam wid h).
FIGURE 3
S11 pa ame e o he p oposed an enna o six di e en posi ions
o he g aphene liquid.
FIGURE 4
S11 pa ame e o he p oposed an enna o di e en olumes o
he g aphene liquid.
FIGURE 5
3D a -field adia ion pa e n o he g aphene-based liquid
an enna a 28 GHz.
F on ie s in Communica ions and Ne wo ks on ie sin.o g06
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3 Discussion
Wi h he g ow h o wi eless communica ion ne wo ks, he e
ha e been significan echnological ad ancemen s in an enna design
in o de o mee he e e -g owing equi emen s o use s Kuma e al.
(2020). The e o e, he u iliza ion o high-pe o mance an ennas o
inc ease co e age and educe he complexi y o a sys em is equi ed
(Alibakhshikena i e al., 2022;Ma asco e al., 2022;Ma asco Pa chin
e al., 2023;Hasan e al., 2022). I is hus expec ed ha 5G an ennas
will be e ec i e in e ms o pola iza ion, gain/di ec i i y, bandwid h,
e ficiency, e c.
Applica ions equi ing mechanically flexible an ennas can
benefi om he use o liquid an ennas. The conduc i e me als
used o make con en ional an ennas, like coppe , make hem
ex emely e ec i e bu un o una ely igid. On he o he hand,
liquid an ennas a e capable o p o iding he equi ed flexibili y
and econfigu abili y. Fo his eason, hey ha e ecen ly gained
significan in e es in he esea ch communi y o wi eless
communica ions. Fluidic and conduc i i y cha ac e is ics a e he
p ima y de e minan s o me allic liquid an enna pe o mance. As
such, a g aphene-based liquid an enna pe o ms be e han he
EGaIn and Me cu y liquid an enna coun e pa s, in e ms o gain,
bandwid h, eflec ion coe ficien , and adia ion e ficiency (Dash
e al., 2023).
G aphene-based liquid an ennas ep esen a e olu iona y
ad ancemen in he field o wi eless communica ions and
an enna echnology. G aphene, a single laye o ca bon a oms
a anged in a hexagonal la ice, o e s excep ional elec ical,
FIGURE 6
Radia ion Gain and Radia ion e ficiency o he an enna o e he
equency band 10–45 GHz. (a) Radia ion Gain. (b)
Radia ion e ficiency.
FIGURE 7
Six wo king modes o he g aphene-based liquid an enna.
FIGURE 8
The no malized adia ion pa e n o he g aphene-based liquid
an enna in six wo king modes a 28 GHz.
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mechanical, and he mal p ope ies. When g aphene is in liquid
o m, i has highly conduc i e and flexible beha iou ha can be
used o c ea e an ennas wi h unp eceden ed cha ac e is ics.
G aphene p oduc ion echniques ha e ad anced significan ly,
leading o mo e cos -e ec i e me hods o la ge-scale
p oduc ion. Addi ionally, he liquid na u e o hese an ennas
simplifies manu ac u ing p ocesses and educes ma e ial was e,
u he enhancing hei cos -e ec i eness and scalabili y
compa ed o con en ional an ennas. G aphene-based liquid
an ennas can be easily modelled in o di e en shapes and allow
o seamless in eg a ion in o a wide ange o de ices and
s uc u es. G aphene’s excep ional elec onic cha ac e is ics
allow o he de elopmen o an ennas ha can ope a e a a
wide ange o equencies. This wideband pe o mance is
c ucial o mode n communica ion sys ems ha mus suppo
mul iple wi eless s anda ds and equencies simul aneously.
G aphene exhibi s excep ional elec ical conduc i i y and low
elec omagne ic losses, esul ing in an ennas wi h high
e ficiency and minimal signal deg ada ion. This cha ac e is ic is
pa icula ly impo an o applica ions equi ing long- ange
communica ions o ope a ion in challenging en i onmen s wi h
high in e e ence o a enua ion.
The o e all elec omagne ic pe o mance o a liquid an enna is
influenced by mul iple pa ame e s, including losses, flexibili y,
adap abili y, econfigu abili y, densi y, oxida ion e ec , and
esidue o ma ion. Beyond conduc i i y, g aphene-based liquid
an ennas o e addi ional ad an ages, such as lowe densi y,
highe mechanical flexibili y, anspa ency, en i onmen al
s abili y and he abili y o be easily p ocessed in mic ofluidic
channels. G aphene me allic liquids also o e ad an ages in
e ms o oxida ion mi iga ion and educed esidue o ma ion,
which helps main ain s able elec ical p ope ies, ensu ing be e
long- e m eliabili y and en i onmen al s abili y. Fu he mo e,
g aphene’s unable conduc i i y enables dynamic impedance
ma ching and beam econfigu a ion, making i pa icula ly well-
sui ed o econfigu able an enna applica ions. In con as , EGaIn
has ce ain limi a ions, such as highe densi y, suscep ibili y o
oxida ion, and po en ial oxici y, which can a ec long- e m
pe o mance. The high densi y and oxida ion-p one na u e o
EGaIn alloys can deg ade he an enna pe o mance o e ime.
Thus, g aphene-based liquid an ennas p o ide supe io o e all
pe o mance making hem mo e sui able o nex -gene a ion
econfigu able and flexible wi eless communica ion sys ems. The
econfigu abili y o g aphene-based liquid an ennas in a
mic ofluidic channel is an addi ional benefi . Addi ional deg ees
o eedom a e made possible by he fluidic na u e o liquid
ma e ials, which imp o es econfigu abili y. In g aphene liquid
an ennas, equency econfigu a ion and beam econfigu a ion
can be accomplished by adjus ing he liquid olume and liquid
mo emen wi hin he mic ofluidic channel a di e en loca ions.
This unabili y allows o adap i e an enna designs ha can op imize
pe o mance based on ne wo k dynamics (e.g., due o mobili y),
changing en i onmen al condi ions o communica ion
equi emen s. In his way, g aphene-based liquid an ennas
add ess he need o high-pe o mance, flexible, and adap able
an ennas in mode n communica ion sys ems. Thei unique
combina ion o p ope ies o e s significan ad an ages o e
con en ional an ennas, pa ing he way o 5G mmWa e wi eless
communica ion sys em.
4 Conclusion
A mic ofluidically beam- econfigu able di ec ional an enna
using g aphene liquid o he mmWa e wi eless communica ion
sys em was p esen ed in his wo k. The econfigu a ion mechanism
o he p oposed an enna is based on he mo emen o he g aphene
liquid inside he mic ofluidic channel. The an enna is ealized in a
ec angula -shaped poly me hyl me hac yla e mic ofluidic channel
o e a liquid c ys al polyme subs a e. The an enna is econfigu ed
in i s adia ion di ec ion, co e ing up o 360°angles wi h six beams
(0°,45°,135°,180°,225°and 315°a an ope a ional equency o
28 GHz. Mo eo e , he an enna p o ides a wideband o
bandwid h abou 22%and a gain o 7 dBi. Fu he mo e,
equency econfigu a ion is achie ed by con olling he olume
o he liquid inside he mic ofluidic channel. The p esen ed esul s
e eal ha he p oposed g aphene-based liquid an enna is p omising
o u u e applica ions in wi eless communica ions. As nex -
gene a ion wi eless ne wo ks demand high-pe o mance
an ennas, he p oposed mic ofluidically beam- econfigu able
an enna using g aphene liquid will ca e o he needs o he e e -
g owing ne wo k use s.
Da a a ailabili y s a emen
The o iginal con ibu ions p esen ed in he s udy a e included in
he a icle/supplemen a y ma e ial, u he inqui ies can be di ec ed
o he co esponding au ho .
Au ho con ibu ions
SD: Concep ualiza ion, Da a cu a ion, Fo mal Analysis,
In es iga ion, Me hodology, So wa e, Supe ision, Valida ion,
W i ing–o iginal d a , W i ing– e iew and edi ing. CP: P ojec
adminis a ion, Resou ces, Supe ision, W i ing– e iew and
edi ing, Concep ualiza ion, Fo mal Analysis, Me hodology,
Valida ion, Visualiza ion. IK: Funding acquisi ion, P ojec
adminis a ion, Resou ces, Supe ision, Visualiza ion,
W i ing– e iew and edi ing, Concep ualiza ion, Fo mal Analysis,
Me hodology, Valida ion.
TABLE 3 Main beam di ec ion o he an enna in di e en posi ions o he
g aphene liquid.
Posi ion o g aphene-liquid Beam di ec ion
P2 D2 (0°)
P3 D3 (45°)
P4 D4 (135°)
P5 D5 (180°)
P6 D6 (225°)
P1 D1 (315°)
F on ie s in Communica ions and Ne wo ks on ie sin.o g08
Dash e al. 10.3389/ cmn.2025.1560311
Funding
The au ho (s) decla e ha financial suppo was ecei ed
o he esea ch, au ho ship, and/o publica ion o his
a icle. This wo k has ecei ed unding om he Eu opean
Union’s Ho izon-JU-SNS esea ch and inno a ion p og amme
unde he p ojec s 6G-LEADER (G an ag eemen No.
101192080) and iSEE-6G (G an ag eemen No. 101139291).
I has also ecei ed unding om he Eu opean Resea ch
Council (ERC) unde he Eu opean Union’s Ho izon 2020
esea ch and inno a ion p og amme (G an ag eemen
No. 819819).
Conflic o in e es
The au ho s decla e ha he esea ch was conduc ed in he
absence o any comme cial o financial ela ionships ha could be
cons ued as a po en ial conflic o in e es .
The au ho (s) decla ed ha hey we e an edi o ial boa d
membe o F on ie s, a he ime o submission. This had no
impac on he pee e iew p ocess and he final decision.
Gene a i e AI s a emen
The au ho (s) decla e ha no Gene a i e AI was used in he
c ea ion o his manusc ip .
Publishe ’s no e
All claims exp essed in his a icle a e solely hose o he au ho s
and do no necessa ily ep esen hose o hei a filia ed
o ganiza ions, o hose o he publishe , he edi o s and he
e iewe s. Any p oduc ha may be e alua ed in his a icle, o
claim ha may be made by i s manu ac u e , is no gua an eed o
endo sed by he publishe .
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