Xiong,X Z; Fusco,V F(Microwave and Optical Technology Letters, August 5, 2002)
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Abstract:
In this Letter a new physical model for metal-insulatormetal
CMOS capacitors is presented. In the model the parameters of the
circuit are derived from the physical structural details. Physical behaviors
due to metal skin effect and inductance have been considered. The
model has been confirmed by 3D EM simulator and design rules proposed.
The model presented is scalable with capacitor geometry, allowing
designers to predict and optimize quality factor. The approach has
been verified for MIM CMOS capacitors
Sona,Kundukulam O; Manju,Paulson; Aanandan,C K; Mohanan, P(Microwave and Optical Technology Letters, August 5, 2002)
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Abstract:
Development of a new compact circular-sided microstrip
antenna is presented. This antenna offers considerable area re- TABLE 2. Variation of Resonant Frequencies
duction compared to standard rectangular microstrip antenna designed
for the same frequency. Typical antenna design and
experimental results for circular polarization are also demonstrated.
77je antenna has a 3-dB axial ratio bandwidth of 1.5%
Dongsheng,Qi; Binhong,Li; Yabin,Zhang; Haitao,Liu(Microwave and Optical Technology Letters, February 3, 2004)
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Abstract:
A novel compact single-layer dual frequency microstrip
antenna which uses an H-shaped geometry with two U-shaped slots embedded
near the radiation edges, is presented. By changing the design parameters, the lower and higher resonant frequencies can be controlled
easily, and a range of frequency ratios (1.716-2.363) can be
obtained in this design. For the two operating frequencies of the proposed
antenna, the same polarization planes and broadside radiation
patterns are achieved. Compared to the regular dualfrequency patch
antenna, this antenna can realize a significant size reduction
A compact single –feed multiband planar antenna configuration
Suitable for GPS, DCS. 2.4/5.8 GHz WLAN applications are presented.
The antenna has dimensions 38 x 3 x 1.6 mm and offers good
radiation and reflection characteristics in the above frequency bands.
The antenna has a simple geometry and can be easily fed using a 50
coaxial probe
Binu, Paul; Mridula, S; Mohanan, P; Bijumon, P V; Sebastian,M T(Microwave and Optical Technology Letters, October 20, 2004)
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Abstract:
very-high-permittivity (e, = 100) multiband dielectrice>
e resonator antenna is presented. The compact antenna, excited by a
m:'crostrip line, resonates at two frequencies centered around the 1.9-
GHz and 2.4-GHz bands with identical polarization . The behavior of the
antenna at different positions along the feed line is studied and optimized.
Multiple resonances with the same polarization and broad radioticn
patterns suggest the suitability of the antenna for multiband wireless
application
A novel compact wideband antenna for wireless local area network
(WLAN) applications in the 2.4 GHz band are presented. The proposed
low profile antenna of dimensions 15 x 14.5 x 1.6 mm offers 18.6%
bandwidth and an average gain of~5 dBi. The antenna can be excited
directly using a 50 coaxial probe
Garcia,Garcia J; Bonache,J; Gil,I; Martin,F; Marques,R; Falcon,F; Lapetegi,T; Laso,M A G; Sorolla,M(Microwave and Optical Technology Letters, February 20, 2005)
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Abstract:
In this paper, microstrip lines magnetically coupled to splitring
resonators (SRRs) are conquved to electromagnetic bundgup (EBG)
nr,rrostrip lines in terns q/ their stop-heard penjbrnmrnce and dimensions. In
bath types o/ trunsmis•siou lines, signal propagation is inhibited in it certain
jequency bwuL For EBG microstrip lines, the central frequency of such a
forbidden band is determined by the period of the structure, whereas in
SRR-hased microstrip lines the position of the frequency gap depends on
the quasi-static resonant frequency of the rings. The main relevant conrributiun
of this paper is to provide a tuning procedure to control the gap width
in SRR microstrip lines, and to show that by using SRRs, device dimensions
ale much smaller than those required by EBGs in order to obtain similar
stop-banal performance. This has been demonstrated by fill-wave electromagnetic
simulations and experimentally verified from the characterization
ql two fabricated microstrip lines: one with rectangular SRRs etched on the
upper substrate side, and the other with a periodic perturbation cf'strip
width. For similar rejection and 1-(;H,. gap width centered at 4.5 Gllz, it
has been found that the SRR microstrip line is•,fve times shorter. In addition,
no ripple is appreciable in the allowed band for the .SRR-hared structure,
whereas due to dispersion, certain mismatch is expected in the EBG
prototype. Due to the high-frequency selectivity, controllable gap width, and
small dimensions, it is believed that SRR coupled to planar transmission
lines can have an actual impact on the design of stop-band filters compatible
with planar technology, and can be an alternative to present solutions based on distributed approaches or EBG
Shavit,R; Taig,I(Microwave and Optical Technology Letters, July 20, 2004)
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Abstract:
In this paper, a comparison study among three neuralnetwork
algorithms for the synthesis of array patterns is presented. The
neural networks are used to estimate the array elements' excitations for
an arbitrary pattern. The architecture of the neural networks is discussed
and simulation results are presented. Two new neural networks,
based on radial basis functions (RBFs) and wavelet neural networks
(WNNs), are introduced. The proposed networks offer a more efficient
synthesis procedure, as compared to other available techniques
Pravinkumar,P A; Mohanan, P; K G Nair(Indian Journal of Radio & Space Physics, December , 1981)
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Abstract:
A technique for improving the coupling between a feed horn and reflector by using corrugated metallic flanges is presented.
Experimental data for flanges of varying parameters are given and theoretical explanation is supplemented
Bagei, A M; Cetin, A E(IEE Electronics letters,UK, October 24, 2002)
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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
Jacob,George; Aanandan,C K; Mohanan, P; K G Nair; Sreemoolanathan,H; Sebastian,M T(Microwave and Optical Technology Letters, February 20, 1998)
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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
Binoy,G S; Aanandan,C K; Mohanan, P; Vasudevan, K(International Journal of Electronics, January 12, 2002)
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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)
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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
Surendran,K P; Sebastian,M T; Mohanan, P; Mohanan,Jacob V(American Institute of Physics, 2005)
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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
Bijumon, P V; Sreedevi, Menon K; Sebastian,M T; Mohanan, P(Microwave and Optical Technology Letters, November 20, 2002)
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Abstract:
A novel technique fitr the bat dividth enhancement of conventional
rectangular microstrip antenna is proposed in this paper. When a
high permittivity dielectric resonator of suitable resonant frequency was
loaded over the patch. the % bandwidth of the antenna was increased by
more than five tunes without much affecting its gain and radiation performance.
A much more improved bandwidth was obtained when the dielectric
resonator was placed on the feedline. Experimental study shows a 2:1
VSWR bandwidth of more than 10% and excellent cross polarization performance
with increased pass band and radiation coverage abnost the same
as that of rectangular microstrip antenna
Lo, H Y; Leung, K W(Microwave and Optical Technology Letters, June 5, 2001)
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Abstract:
A new configuration that employs a conducting conformal
strip to excite the low-profile equilaterial-triangular dielectric resonator
antenna (DRA) of very high permittivity is proposed. As compared with
the previous aperture-coupling configuration, the new configuration has
a wider impedance bandwidth (- 5.5%) and a higher front-to-back
radiation ratio. The return loss, radiation patterns, and antenna gain are
measured and discussed
Hunagund,P V; Jose,K A; Mohanan, P; Nair, K G(Indian Journal of Radio & Space Physics, February , 1992)
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Abstract:
Results of exhaustive study of the effect of metallic flanges on H-plane radiation characteristics of V-slot
waveguide antenna are presented . It has been established that the beam can be sharpened or broadened by
varying the flange angle . The adjustment of the flange angle and flange width would further improve the
radiation pattern , yielding optimum efficiency from the flanged system