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
Aanandan,C K; Mohanan, P; Supriyo,Dey; K G Nair(Department of Electronics, 1994)
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Abstract:
A simple technique to improve the impedance bandwidth of a circular
microstrip patch antenna using two sectorial slots is proposed. Using this
design more than 5% impedance bandwidth is obtained. The added
advantage of this new antenna is that it can be fed by a 50 microstrip
line.
Aanandan,C K; K G Nair; Mohanan, P; Jacob,George(Department of Electronics, November , 1998)
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Abstract:
A new compact microstrip antenna element is analyzed.
The analysis can accurately predict the resonant frequency,
input impedance, and radiation patterns. The predicted results
are compared with experimental results and excellent agreement
is observed . These antenna elements are more suitable in applications
where limited antenna real estate is available
Bindu, G; Santhosh John, Abraham; Anil, Lonappan; Vinu, Thomas; Aanandan,C K; Mathew, K T(International Journal of Cancer Research, 2006)
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Abstract:
Despite its recognized value in detecting and characterizing breast disease, X-ray
mammography has important limitations that motivate the quest for alternatives to augment
the diagnostic tools that are currently available to the radiologist. The rationale for pursuing
electromagnetic methods are based on the significant dielectric contrast between normal
and cancerous breast tissues, when exposed to microwaves. The present study analyzes
two-dimensional microwave tomographic imaging on normal and malignant breast tissue
samples extracted by mastectomy, to assess the suitability of the technique for early
detection ofbreast cancer. The tissue samples are immersed in matching coupling medium
and are illuminated by 3 GHz signal. 2-D tomographic images ofthe breast tissue samples
are reconstructed from the collected scattered data using distorted Born iterative method.
Variations of dielectric permittivity in breast samples are distinguishable from the obtained
permittivity profiles, which is a clear indication of the presence of malignancy. Hence
microwave tomographic imaging is proposed as an alternate imaging modality for early
detection ofbreast cancer.
Bindu, G; Anil, Lonappan; Vinu, Thomas; Aanandan,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; Aanandan,C K; Mathew, K T(Progress In Electromagnetics Research, 2006)
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Abstract:
Active microwave imaging is explored as an imaging
modality for early detection of breast cancer. When exposed to
microwaves, breast tumor exhibits electrical properties that are
significantly different from that of healthy breast tissues. The
two approaches of active microwave imaging — confocal microwave
technique with measured reflected signals and microwave tomographic
imaging with measured scattered signals are addressed here. Normal
and malignant breast tissue samples of same person are subjected to
study within 30 minutes of mastectomy. Corn syrup is used as coupling
medium, as its dielectric parameters show good match with that of
the normal breast tissue samples. As bandwidth of the transmitter is
an important aspect in the time domain confocal microwave imaging
approach, wideband bowtie antenna having 2:1 VSWR bandwidth
of 46% is designed for the transmission and reception of microwave
signals. Same antenna is used for microwave tomographic imaging too
at the frequency of 3000 MHz. Experimentally obtained time domain
results are substantiated by finite difference time domain (FDTD)
analysis. 2-D tomographic images are reconstructed with the collected
scattered data using distorted Born iterative method. Variations of
dielectric permittivity in breast samples are distinguishable from the
obtained permittivity profiles.
Bindu, G; Vinu, Thomas; Anil, Lonappan; Aanandan,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.
Gijo,Augustin; Shynu, S V; Mohanan, P; Aanandan,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.
Bindu, G; Anil, Lonappan; Vinu, Thomas; Aanandan,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.
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.
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.