Aanandan,C K; Mohanan,P; K G Nair(Department of Electronics, August 13, 1984)
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Abstract:
Design and development of a circularly polarized and matched H-plane sectorial horn antenna have been reported By
proper trimming of the flange parameters any desired polarization can be obtained from the horn
Deepti Das, Krishna; Aanandan, C K; Mohanan, P; Vasudevan, K(John Wiley & Sons, March 3, 2006)
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Abstract:
Design of a dual-port circular patch antenna with a sector-slot for dual-frequency operation is presented. The antenna resonates at two distinct frequencies with orthogonal polarizations and broad radiation characteristics. Unlike the conventional circular patch, this antenna can be microstrip-fed to operate at either of the resonances. The two polarizations can be simultaneously excited using two electromagnetically coupled ports with an isolation better than −30 dB between the ports. This antenna has the added advantage of size reduction of 44% compared to the conventional circular patch without any reduction in gain.
Laila, D; Deepu, V; Sujith, R; Aanandan, C K; Vasudevan, K; Mohanan, P(Wiley InterScience, May , 2009)
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Abstract:
An asymmetric coplanar strip-fed uniplanar antenna for wideband applications is presented. The resulting antenna offers a 2:1 VSWR bandwidth greater than 100% from 1.58 to 5.48 GHz covering the DCS/PCS/IEEE 802.11a/WiMAX bands. The antenna has an overall dimension of 44 × 35 mm2 when printed on a substrate of dielectric constant 4.4 and height 1.6 mm. The design equation is also presented in this article. The antenna exhibits good radiation characteristics and moderate gain in the entire operating band.
Gijo, Augustin; Shynu, S V; Mohanan, P; Anandan, C K; Vasudevan, K(Electronics Letters, April 27, 2006)
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Abstract:
A compact dual-band printed antenna covering the 2.4 GHz (2400-2485 MHz) and 5.2 GHz (5150-5350 MHz) WLAN bands is presented. The experimental analysis shows a 2:1 VSWR bandwidth of up to 32 and 8% for 2.4 and 5.2 GHz, respectively. The measured radiation patterns are nearly omnidirectional, with moderate gain in both the WLAN bands.
Sujith, R; Deepu, V; Laila, D; Aanandan, C K; Vasudevan, K; Mohanan, P(Wiley InterScience, April , 2009)
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Abstract:
A compact, dual band coplanar waveguide fed modified T-shaped uniplanar antenna is presented. The antenna has resonances at 1.77 and 5.54 GHz with a wide band from 1.47–1.97 GHz and from 5.13–6.48 GHz with an impedance bandwidth of 34% and 26%, respectively. Also the antenna has an average gain of 3 dBi in lower band and 3.5 dBi in higher band with an average efficiency of 90%.
Deepti Das, Krishna; Gopikrishna, M; Aanandan, C K; Mohanan, P; Vasudevan, K(PIER, 2008)
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Abstract:
Design of a compact dual frequency microstrip antenna
is presented. The structure consists of a slotted circular patch with
a dielectric superstrate. The superstrate,not only acts as a radome,
but improves the bandwidth and lowers the resonant frequency also.
The proposed design provides an overall size reduction of about 60%
compared to an unslotted patch along with good efficiency,gain
and bandwidth. The polarization planes at the two resonances are
orthogonal and can be simultaneously excited using a coaxial feed.
Parametric study of this configuration showed that the frequency ratio
of the two resonances can be varied from 1.17 to 1.7 enabling its
applications in the major wireless communication bands like AWS,
DECT,PHS,Wi.Bro, ISM,and DMB. Design equations are also
deduced for the proposed antenna and validated.
Deepti Das, Krishna; Gopikrishna, M; Anandan, C K; Mohanan, P; Vasudevan, K(Electronics Letters, August 3, 2006)
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Abstract:
Design of a dual linearly-polarised microstrip patch antenna, excited
by two orthogonal microstrip feed lines, is presented. A reduction in
patch size of 35% is obtained when compared to a square patch
operating at the same frequency. The polarisations are oriented at +45
and - 45 with an isolation of more than 36 dB between the ports.
Unlike earlier designs, the proposed structure provides better gain.
Aanandan,C K; Mohanan,P; Vasudevan,K; Shynu,S V; Gijo,Augustin(Department of Electronics, 2004)
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Abstract:
A novel design of a computer electronically reconfigurable dual frequency dual polarized single feed hexagonal slot loaded microstrip antenna in L-band is introduced in this chapter. pin diodes are used to switch the operating frequencies considerably without much affecting the radiation characteristics and gain. the antenna can work with a frequency ratio varying in the wide range from 1.2 to 1.4. the proposed design has an added advantage of size reduction up to 72.21% and 46.84% for the two resonating frequencies compared to standard rectangular patches. the design also gives considerable bandwidth of up to 2.82% and 2.42 % for the operating frequencies.
Thomas, Paulbert; Gopikrishna, M; Aanandan, C K; Mohanan, P; Vasudevan, K(Wiley InterScience, October , 2010)
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Abstract:
Design of a compact microstrip-fed ultra-wideband antenna suitable for USB dongle and other such space constraint applications is presented. The structure consists of a pentagonal monopole element and a modified ground plane that gives an impedance bandwidth from 2.8 to 12 GHz. Radiation patterns are stable and omni-directional throughout the band with an average gain of 2.84 dBi. The antenna occupies only 11 × 30 mm2 on FR4 substrate with permittivity 4.4.
Deepu, V; Rohith, K R; Manoj, J; Suma, M N; Vasudevan, K; Aanandan, C K; Mohanan, P(Electronics Letters, January 18, 2007)
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Abstract:
A compact dual-band uniplanar antenna for operation in the 2.4/5.2/5.8 GHz WLAN/HIPERLAN2 communication bands is presented. The dual-band antenna is obtained by modifying one of the lateral strips of a slot line, thereby producing two different current paths. The antenna occupies a very small area of 14.5times16.6 mm2 including the ground plane on a substrate having dielectric constant 4.4 and thickness 1.6 mm at 2.2 GHz. The antenna resonates with two bands from 2.2 to 2.52 GHz and from 5 to 10 GHz with good matching, good radiation characteristics and moderate gain
Shynu, S V; Augustin, G; Aanandan, C K; Mohanan, P; Vasudevan, K(IET, March 16, 2006)
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Abstract:
A new electronically reconfigurable dual frequency microstrip patch antenna with highly simplified varactor tuning circuitry is presented. The proposed design allows relatively independent selection of the two operating frequencies. Tuning ranges of 7.1 and 4.1% are realised for the two resonant frequencies without the use of any matching circuits.
Gopikrishna, M; Deepti Das, Krishna; Aanandan, C K; Mohanan, P; Vasudevan, K(Wiley InterScience, April , 2009)
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Abstract:
The design and performance of a stepped slot printed monopole antenna in the ultrawideband is presented in this article. Multiple resonances generated by the stepped slot geometry are matched in the ultrawideband using a modified microstrip feed. The impedance bandwidth (SWR < 2) of the antenna is from 3 to 11 GHz. Radiation patterns are stable and omnidirectional with appreciable gain throughout the band. Performance of the antenna is also analyzed in the time domain, which reveals good pulse handling capabilities. Compact geometry of the antenna allows easy commercial deployment.
Shynu, S V; Gijo, Augustin; Anandan, C K; Mohanan, P; Vasudevan, K(Progress In Electromagnetics Research, 2006)
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Abstract:
The design of a compact, single feed, dual frequency
dual polarized and electronically reconfigurable microstrip antenna is
presented in this paper. A square patch loaded with a hexagonal slot
having extended slot arms constitutes the fundamental structure of
the antenna. The tuning of the two resonant frequencies is realized by
varying the effective electrical length of the slot arms by embedding
varactor diodes across the slots. A high tuning range of 34.43%
(1.037–1.394 GHz) and 9.27% (1.359–1.485 GHz) is achieved for the
two operating frequencies respectively, when the bias voltage is varied
from 0 to −30 V. The salient feature of this design is that it uses no
matching networks even though the resonant frequencies are tuned in
a wide range with good matching below −10 dB. The antenna has an
added advantage of size reduction up to 80.11% and 65.69% for the two
operating frequencies compared to conventional rectangular patches.
Bindu, G; Anil, Lonappan; Vinu, Thomas; Anandan, C K; Mathew, K T(Progress In Electromagnetics Research, 2006)
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Abstract:
Permittivity and conductivity studies of corn syrup in
various concentrations are performed using coaxial cavity perturbation
technique over a frequency range of 250 MHz–3000 MHz. The results
are utilized to estimate relaxation time and dipole moments of the
samples. The stability of the material over the variations of time is
studied. The measured specific absorption rate of the material complies
with the microwave power absorption rate of biological tissues. This
suggests the feasibility of using corn syrup as a suitable, cost effective
coupling medium for microwave breast imaging. The material can also
be used as an efficient breast phantom in microwave breast imaging
studies.
Bindu, G; Anil, Lonappan; Vinu, Thomas; Anandan, C K; Mathew, K T(Springer, November 1, 2006)
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Abstract:
Phantoms that exhibit complex dielectric
properties similar to low water content biological tissues
over the electromagnetic spectrum of 2–3 GHz
have been synthesized from carbon black powder,
graphite powder and polyvinyl-acetate-based adhesive.
The materials overcome various problems that are
inherent in conventional phantoms such as decomposition
and deterioration due to the invasion of bacteria
or mold. The absorption coefficients of the materials
for various compositions of carbon black and graphite
powder are studied. A combination of 50% polyvinylacetate-
based adhesive, 20% carbon black powder and
30% graphite powder exhibits high absorption coefficient,
which suggests another application of the material
as good microwave absorber for interior lining of
tomographic chamber in microwave imaging. Cavity
perturbation technique is adopted to study the dielectric
properties of the material.
Sarin, V P; Nishamol, M S; Gijo, Augustin; Mohanan, P; Aanandan, C K; Vasudevan, K(John Wiley & Sons, July , 2008)
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Abstract:
A new design of a dual-band dual-polarized electromagnetically coupled slot loaded square patch antenna, covering the WLAN 5.2 GHz and 5.8 GHz bands, achieving bandwidth enhancement by using tapered slot structure, is presented here. The proposed antenna covers 5.09–5.47 GHz and 5.7–5.88 GHz bands. Details of the antenna design along with experimental and simulated results are presented and discussed.
Jitha, B; Bybi, P C; Aanandan, C K; Mohanan, P(John Wiley & Sons, June , 2008)
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Abstract:
Design of a compact microstrip band reject filter is proposed. The device consists of an Open Loop Rectangular Resonator (OLRR) coupled to a microstrip line. The transmission line has a U-bend which enhances the coupling with the OLRR element and reduces the size of the filter. The filter can be made tunable by mounting variable capacitance to the system. Simulated and experimental results are presented.
Bindu, G; Vinu, Thomas; Anil, Lonappan; Anandan, C K; Mathew, K T(John Wiley & Sons, January , 2006)
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Abstract:
A phantom that exhibits complex dielectric properties similar to low-water-content biological tissues over the electromagnetic spectrum of 2000–3000 MHz has been synthesized from carbon black, graphite powder, and poly vinyl acetate (PVA)-based adhesive. The material overcomes various problems that are inherent in conventional phantoms such as decomposition and deterioration due to the invasion of bacteria or mold. The absorption coefficients of the material for various concentrations of carbon and graphite are studied. A combination of 50% poly-vinyl-acetate-based adhesive, 20% carbon, and 30% graphite exhibits a high absorption coefficient, which suggests another application of the material as a good microwave absorber for the interior lining of tomographic chamber in microwave imaging. The cavity-perturbation technique is adopted to study the dielectric properties of the material.