1240 IEEE TRANSACTIONS ON NANOTECHNOLOGY, VOL. 13, NO. 6, NOVEMBER 2014
High-Performance Resonator Based on Multiwalled
Carbon Nanotube (MWCNT)
Yi Huang, Lin-Sheng Wu, Member, IEEE, Min Tang, Member, IEEE, and Jun-Fa Mao, Fellow, IEEE
Abstract—A half-wavelength multiwalled carbon nanotube
(MWCNT) microstrip resonator is proposed and analyzed in
this paper. Its resonant frequency, as well as the correspond-
ing unloaded Q-factors, is predicted by using the multiconductor
transmission-line (MTL) model and the equivalent single conduc-
tor (ESC) model. The MTL model provides an accurate solution for
both the resonant frequency and Q-factors. Although the resonant
frequency can be captured approximately with the ESC model, the
calculated Q-factors are with low accuracy. By properly selecting
the geometric dimensions according to the curves obtained with
the MTL model, MWCNT resonators can be designed easily for
a specific resonant frequency. Further, the radius-dependent char-
acteristic of temperature drift of the resonator is explored. The
superior performance and potential applications of the MWCNT
resonator are illustrated by numerical results.
Index Terms—Half-wavelength resonator, multiwalled carbon
nanotube (MWCNT), resonant frequency, temperature drift, un-
loaded Q-factor.
I. INTRODUCTION
C
ARBON nanotubes (CNTs) have excellent mechanical,
thermal, chemical, and electrical properties, which have
been demonstrated by much research since their discovery in
1991 [1]–[4]. Depending on the charity, CNTs can behave
as metallic or semiconducting materials. The semiconducting
CNTs are usually applied in field effect transistors (FETs), while
the metallic CNTs are considered to have significant potentials
in the interconnection due to their high conductivity and large
current handling capability [5]–[10]. In high-frequency applica-
tions, since the skin effect in CNTs is different from that in free
electron systems, the CNTs have much better conductive per-
formance in comparison with conventional metals. Therefore,
CNTs can potentially be applied for microwave and millimeter-
wave passive components and circuits, such as resonators and
filters [11]–[13].
In [11], a gigahertz resonator based on a single-walled carbon
nanotube (SWCNT) is presented. Compared with SWCNTs,
multiwalled carbon nanotubes (MWCNTs) are more suitable to
Manuscript received December 2, 2013; revised May 13, 2014; accepted
September 4, 2014. Date of publication September 17, 2014; date of current
version November 6, 2014. This work was supported by the National Science
Foundation of China under Grants 61331004 and 61234001. The review of this
paper was arranged by Associated Editor L. Dong.
The authors are with the Key Laboratory of Ministry of Education of
Design and Electromagnetic Compatibility of High-Speed Electronic Sys-
tems, Shanghai Jiao Tong University, Shanghai 200240, China (e-mail:
huangyi103@sjtu.edu.cn; wallish@sjtu.edu.cn; tm222@sjtu.edu.cn; jfmao@
sjtu.edu.cn).
Color versions of one or more of the figures in this paper are available online
at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TNANO.2014.2358641
build up resonators because MWCNTs have much more con-
ducting channels. Furthermore, since the MWCNTs have many
large-diameter shells, they have relatively long mean free paths
[14], [15] and even the semiconducting shells can be conduc-
tive [16]. Thus, the conducting performance of the MWCNT
is better than the SWCNT bundle with the same geometry,
which leads to less power dissipation in MWCNT resonators.
As a consequence, the unloaded Q-factor of an MWCNT res-
onator is expected to be higher than that of an SWCNT one.
A half-wavelength microstrip resonator based on an array of
MWCNTs, with high unloaded Q-factor, has been proposed and
simply characterized by the authors [13]. In [13], the MWCNT
is considered as a parallel connection of CNT shells, where the
couplings between the shells are ignored. The resonator perfor-
mance is roughly estimated under such an assumption.
Although the MWCNT consists of an array of concentric
rolled graphene layers, it is not a simple combination of par-
allel shells in circuit modeling due to the existence of mutual
inductances and electrostatic capacitance among them. In re-
cent years, several modeling approaches have been proposed
to analyze MWCNTs, such as the equivalent single conductor
(ESC) model and the multiconductor transmission-line (MTL)
model [17]–[19]. The ESC model is based on the assumption
that the voltages at arbitrary cross section of the MWCNT are
with the same value when it is excited in common mode config-
uration. With the ESC model, the MWCNT is governed by the
simplified equations of a single transmission line. Therefore, the
computational complexity is reduced significantly and the fast
simulation of the MWCNT becomes possible. As demonstrated
in [19], the ESC model is accurate when applied for intercon-
nects. However, for the MWCNT resonator, it is important to
obtain the current distribution on the shells for the performance
characterization, where the MTL method is more suitable.
In this paper, a half-wavelength microstrip MWCNT res-
onator is designed and its performance is carefully analyzed.
In Section II, the equivalent circuit of the MWCNT resonator
is given; the resonant frequency, as well as the corresponding
Q-factors, is calculated and compared with the ESC and MTL
models. In Section III, different kinds of power dissipation in
the MWCNT resonator are evaluated in detail with the MTL
model and the Q-factors of the proposed resonator are derived. In
Section IV, the effect of the temperature drift is further investi-
gated. A short conclusion is drawn in Section V.
II. C
IRCUIT MODEL OF MWCNT RESONATOR
AT HIGH FREQUENCIES
The configuration of a half-wavelength MWCNT microstrip
resonator is shown in Fig. 1. A single MWCNT is placed on the
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