Bagei, A M; Cetin, A E(IEE Electronics letters,UK, October 24, 2002)
[+]
[-]
Abstract:
A method for computer- aided diagnosis of micro calcification clusters
in mammograms images presented . Micro calcification clus.eni which
are an early sign of bread cancer appear as isolated bright spots in
mammograms. Therefore they correspond to local maxima of
the image. The local maxima of the image is lint detected and they
are ranked according to it higher-order statistical test performed over
the sub band domain data
Shynu, S V; Gijo,Augustin; Aanandan,C K; Mohanan, P; Vasudevan, K(Microwave and Optical Technology Letters, August 20, 2005)
[+]
[-]
Abstract:
A new design for a compact electronically reconffgurable
singlefeed dual frequency dual-polarized operation of a square-microstrip
antenna capable of achieving tunable frequency ratios in the range
1.1 to 1.37 is proposed and experimentally studied. Varactor diodes inlegruted
with the arms of the hexagonal slot and embedded in the
square patch are used to tune the operating frequencies by applying
reverse-bias voltage. The design has the advantage of size reduction up
to 73.21% and 49.86% for the two resonant frequencies, respectively, as
compared to standard rectangular patches. The antenna offers good
bandwidth of 5.74% and 5.36% for the two operating frequencies. A
highly simplified tuning circuitry without any transmission lines adds to
the compactness of the design
Jacob,George; Aanandan,C K; Mohanan, P; K G Nair; Sreemoolanathan,H; Sebastian,M T(Microwave and Optical Technology Letters, February 20, 1998)
[+]
[-]
Abstract:
A new method for enhancing the 2.1 VSWR impedance
bandwidth of microstrip antennas is presented. Bandwidth enhancement
is achieved by loading the microstrip antenna by a ceramic microwave
dielectric resonator (DR). The validity of this technique has been established
using rectangular and circular radiating geometries. This method
improves the bandwidth of a rectangular microstrip antenna to more
than 10% (= 5 times that of a conventional rectangular microstrip
antenna) with an enhanced gain of I dB
Ceramic dielectrics with high dielectric constant in the microwave frequency range are used as filters, oscillators [I], etc. in microwave integrated
circuits (MICs) particularly in modern communication systems like cellular telephones and
satellite communications. Such ceramics, known as 'dielectric resonators (DRs),donot
only offer miniaturisation and reduce the weight of the microwave components. but also
improve the efficiency of MICs
Biju Kumar, S; Mathew, K T; Raveendranath, U; Augustine,P(lnternational Microwave Power Institute, 2001)
[+]
[-]
Abstract:
In the medical field, microwaves play a larger role for treatment than diagnosis. For the detection of diseases by microwave methods, it is essential to know the dielectric properties of biological materials. For the present study, a cavity perturbation technique was employed to determine the dielectric properties of these materials. Rectangular cavity resonators were used to measure the complex permittivity of human bile, bile stones, gastric juice and saliva. The measurements were carried out in the S and J bands. It is observed that normal and infected bile have different dielectric constant and loss tangent. Dielectric constant of infected bile and gastric juice varies from patient to patient. Detection and extraction of bile stone with possible method of treatment is also discussed.
Mathew, K T; Biju Kumar, S; Anil, Lonappan; Joe, Jacob; Jacob, Samuel; Thommachan, Xavier; Thomas, Kurian(Elsevier Science, October , 2002)
[+]
[-]
Abstract:
Ionic polymers (ionomers) with interesting characteristics are emerging as important commercial polymers. Ionomers have
the unique ability to behave as cross-linked materials at ambient temperatures and to melt and flow at elevated temperatures like
thermoplastics. The complex permittivity and conductivity of a class of ionomers at microwave frequencies are determined
using the cavity perturbation technique and the results are presented.
Bindu, G; Anil, Lonappan; Vinu, Thomas; Aanandan,C K; Mathew, K T(Progress In Electromagnetics Research, 2006)
[+]
[-]
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(Springer, November 1, 2006)
[+]
[-]
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.
Tessamma, Thomas; Tina, George P(BioMed Central Ltd, January 18, 2010)
[+]
[-]
Abstract:
This paper compares the most common digital signal processing methods of exon
prediction in eukaryotes, and also proposes a technique for noise suppression in exon prediction.
The specimen used here which has relevance in medical research, has been taken from the public
genomic database - GenBank.Here exon prediction has been done using the digital signal processing methods viz.
binary method, EIIP (electron-ion interaction psuedopotential) method and filter methods. Under
filter method two filter designs, and two approaches using these two designs have been tried. The
discrete wavelet transform has been used for de-noising of the exon plots.Results of exon prediction based on the methods mentioned above, which give values
closest to the ones found in the NCBI database are given here. The exon plot de-noised using
discrete wavelet transform is also given.Alterations to the proven methods as done by the authors, improves performance
of exon prediction algorithms. Also it has been proven that the discrete wavelet transform is an
effective tool for de-noising which can be used with exon prediction algorithms
Sona,Kundukulam O; Manju,Paulson; Aanandan,C K; Mohanan, P; Vasudevan, K(Microwave and Optical Technology Letters, June 5, 2000)
[+]
[-]
Abstract:
Experimental studies on a compact dual frequency microstrip
antenna are presented. This antenna configuration provides an
area reduction of 40% compared to a standard rectangular antenna
operating at the same frequency without much degradation of the gain.
The antenna structure can be modified to achieve the desired ratio
between the two resonant frequencies
Binoy,G S; Aanandan,C K; Mohanan, P; Vasudevan, K(International Journal of Electronics, January 12, 2002)
[+]
[-]
Abstract:
A new design of' a dual-frequency dual-polarized square microsh'ip antenna fed
along the diagonal, embedded with a square slot having three extended stubs for
frequency tuning, is introduced. The proposed antenna was fabricated using a
standard photolithographic method and the antenna was tested using the HP
3510(:; Vector Network Analyser. The antenna is capable of generating dual
resonant frequencies with mutually perpendicular polarizations and broad
radiation pattern characteristics. Such dual-frequency designs find wide
applications in personal mobile handsets combining GSM and CDS 1800 modes,
and applications in which different frequencies are used for emission and reception
such as personal satellite communications and cellular network systems.
Sona,Kundukulam O; Manju,Paulson; Aanandan,C K; Mohanan, P(Microwave and Optical Technology Letters, September 20, 2002)
[+]
[-]
Abstract:
Experimental and simulated results for a dual-port
dual-polarized microstrip antenna are presented. The antenna excites
two orthogonally polarized resonant frequencies providing an isolation
of -30 dB between the ports. The patch geometry consists of
two circular arcs of different radii with their centers displaced by a
distance. This new design offers an area reduction of -70% coinpared
to it standard rectangular microstrip antenna with a reduction
in gain of 1.7 dB
Mohanan, T(American Institute of Physics, August 22, 2005)
[+]
[-]
Abstract:
The effect of dopants with different valencies and ionic radii on the densification, structural
ordering, and microwave dielectric properties of Ba(Mg1/3Ta2/3)O3 (BMT) is investigated. It is
found that dopants such as Sb2O5, MnO, ZrO2, WO3, and ZnO improve the microwave dielectric
properties of BMT. Addition of trivalent dopants is detrimental to the cation ordering and dielectric
properties of BMT. A correlation between the microwave dielectric properties of BMT and ionic
radii of the dopant has been established. The variation of the dielectric properties of pure and doped
BMT at cryogenic temperatures is also discussed.
Surendran,K P; Sebastian,M T; Mohanan, P; Mohanan,Jacob V(American Institute of Physics, 2005)
[+]
[-]
Abstract:
The effect of dopants with different valencies and ionic radii on the densification, structural
ordering, and microwave dielectric properties of Ba(Mg1t3Tazt3)O3 (BMT) is investigated. It is
found that dopants such as Sb,05, MnO, ZrO,, WO1, and ZnO improve the microwave dielectric
properties of BMT. Addition of trivalent dopants is detrimental to the cation ordering and dielectric
properties of BMT. A correlation between the microwave dielectric properties of BMT and ionic
radii of the dopant has been established. The variation of the dielectric properties of pure and doped
BMT at cryogenic temperatures is also discussed
The effect of glass additives on the densification , phase evolution, microstructure and microwave dielectric properties of Ba(Mg1;3
Ta2i3)03 (BMT) was investigated . Different weight percentages of quenched glass such as B203 , Si02, B203-SiO2, ZnO-B203,
5ZnO-2B2O3, Al203-SiO2, Na20-2B203.10H20, BaO-B203-SiO2, MgO-B203-SiO2, PbO-B203-SiO2 , ZnO-B203-SiO2 and
2MgO-Al203-5SiO2 were added to calcined BMT precursor . The sintering temperature of the glass -added BMT samples were
lowered down to 1300 °C compared to solid-state sintering where the temperature was 1650 °C. The formation of high temperature
satellite phases such as Ba5Ta4O15 and Ba7Ta6O22 were found to be suppressed by the glass addition . Addition of glass systems such
as B203, ZnO-B203, 5ZnO-2B203 and ZnO-B203-SiO2 improved the densification and microwave dielectric properties. Other
glasses were found to react with BMT to form low-Q phases which prevented densification . The microwave dielectric properties of
undoped BMT with a densification of 93 . 1 % of the theoretical density were Cr = 24 . 8, Tr = 8 ppm/°C and Q„ x f= 80,000 GHz. The
BMT doped with 1.0 wt% of B203 has Q„ x f = 124,700GHz, Cr = 24.2, and T f = -1.3 ppm /°C. The unloaded Q factor of 0.2 wt%
ZnO-B203-doped BMT was 136,500 GHz while that of 1.0 wt% of 5ZnO-2B203 added ceramic was Q„ x f= 141,800 GHz . The best
microwave quality factor was observed for ZnO -B203-SiO2 (ZBS) glass-added ceramics which can act as a perfect liquid-phase
medium for the sintering of BMT. The microwave dielectric properties of 0.2wt% ZBS-added BMT dielectric was
Q„ x f= 152,800 GHz, F,= 25.5, and Tr = - 1.5 ppm/°C
Sarin, V P; Nishamol, M S; Gijo,Augustin; Mohanan, P; Aanandan,C K; Vasudevan, K(John Wiley & Sons, July , 2008)
[+]
[-]
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.
In this paper, a dual port, dual frequency, dual polarized,
octagonal shaped Microstrip patch antenna, suitable for GPS
applications is discussed experimentally and theoretically. The
proposed antenna configuration is characterized by good
impedance bandwidth, gain, isolation between two ports and
broad radiation patterns
Description:
Personal Wireless Communications, 2005. ICPWC 2005. 2005 IEEE International Conference on,PP 305-307