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7. R.A. Bhatti, Y.T. Im, N.N. Anh, and S.O. Park, Multiband internal
monopole antenna for mobile phones, Microwave Opt Technol Lett
51 (2009), 739–742.
8. C.T. Lee and K.L. Wong, Uniplanar coupled-fed printed PIFA for
WWAN/WLAN operation in the mobile phone, Microwave Opt
Technol Lett 51 (2009), 1250–1257.
9. C.C. Chen, C.Y.D. Sim, and F.S. Chen, Novel compact quad-band
narrow strip-loaded printed monopole antenna, IEEE Antennas
Wireless Propag Lett 8 (2009), 974–976.
10. K.S. Yoon, S. B. Park, S. Min Kim, and W.G. Yang, Penta-band
internal antenna for mobile handset applications using
parasitic element, Microwave Opt Technol Lett 50 (2008), 3045–3048.
11. P. Ciais, R. Staraj, G. Kossiavas, and C. Luxey, Design of an inter-
nal quad-band antenna for mobile phones, IEEE Microwave Wire-
less Compon Lett 14 (2004), 148–150.
12. C.I. Lin and K.L. Wong, Internal hybrid antenna for multiband operation
in the mobile phone, Microwave Opt Technol Lett 50 (2008), 38–42.
13. C.H. Wu and K.L. Wong, Internal hybrid loop/monopole slot
antenna for quad-band operation in the mobile phone, Microwave
Opt Technol Lett 50 (2008), 795–801.
14. C.Y.D. Sim, P.C. Cheng, and C.H. Lee, Low-profile multiband pla-
nar hybrid antenna design for mobile handset applications, Micro-
wave Opt Technol Lett 53 (2011), 910–915.
VC 2012 Wiley Periodicals, Inc.
COMMENTS ON ‘‘A TRIANGULARDIELECTRIC RESONATOR ANTENNAEXCITED BY A COAXIAL PROBE’’
Sudipta Maity and Bhaskar GuptaDepartment of Electronics and Tele-Communication Engineering,Jadavpur University, Kolkata 700032, India
Received 19 September 2011
ABSTRACT: Original article published Microwave Opt Technol Lett
30:340–341, 2001. VC 2012 Wiley Periodicals, Inc. Microwave Opt
Technol Lett 54:1548, 2012; View this article online at
wileyonlinelibrary.com. DOI 10.1002/mop.26808
Key words: dielectric resonator antenna; transcendental equation
In the above communication [1], Ahmed A. Kishk has given
an approximate expression to compute the resonant frequency of
an equilateral triangular dielectric resonator antenna (DRA) with
height h and an equi-triangular uniform cross section with a side
length Ld, placed on a ground plane. He has given a transcen-
dental equation for computing the wave number kz in the zdirection as given below:
kz tan kzh� p=2ð Þ ¼ er � 1ð Þ � kz½ �1=2 (1)
where er is the relative permittivity of DRA. Hence, the reso-
nance frequency can be found by using the following expres-
sion:
fmn ¼ c
2pffiffiffiffier
p 4p3Ld
� �2
m2 þ mnþ n2� �þ k2z
" #1=2
(2)
where c is the velocity of light in free space. He has used the
resonance frequency index mn instead of mnl because
l ¼ mþ nð Þ (3)
But by applying image theory to remove the ground plane at
z ¼ 0 and enforcing continuity of tangential field to the surface
of dielectric resonator at z ¼ 6h, for TM to z mode, the follow-
ing transcendental equation will result
kz tan kzh� p=2ð Þ ¼ er � 1ð Þk20 � k2z� �1=2
(4)
where k0 denotes the free-space wave number corresponding to
the resonant frequency. Equation (4) satisfies all the data of col-
umn 2 of Table 1 in that communication [1]. It might have been
a typographical error. Hence, Eq. (1) of the above-mentioned ar-
ticle [1] must be corrected or replaced by Eq. (4).
Now, the DRA has triangular cross section. Hence, we need
triangular co-ordinate of a point which can be found by trilinear
transformation. For equilateral triangular cross section, we have
to use homogeneous trilinear coordinates [2] which satisfy the
relation:
lþ mþ n ¼ 0 (5)
Hence,
l ¼ � mþ nð Þ (6)
Similarly, the expression for third index (l) in that article [1]
must be corrected or replaced by Eq. (6).
REFERENCES
1. A.A. Kishk, Microwave Opt Technol Lett 30 (2001), 340–341.
2. S.A. Schelkunoff, Electromagnetic waves, Van Nostrand, New
York, 1943, pp. 393–396.
VC 2012 Wiley Periodicals, Inc.
1548 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 54, No. 6, June 2012 DOI 10.1002/mop
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