Negative magnetic permeability media
(NMPM) can be built up by using small resonant metallic
particles like Split ring resonator (SRR) which has very
high magnetic polarisability. A group of these particles
shows a negative permeability region near and above the
resonant frequency. The continuous medium parameters
describing the SRR array can be predicted from their
individual electromagnetic behavior near the resonances.
The paper presents an optimizing software using Genetic
Algorithm (GA) to design an edge coupled two ring SRR
for a particular frequency
Description:
Recent Advances in Microwave Theory and Applications, 2008. MICROWAVE 2008. International Conference on
A new group of compounds with composition (Ba5-xSrx) Nb4015, having high
permittivity and low loss have been prepared and characterized in the microwave
frequency region . X-ray diffraction studies showed that monophase compound
existed for all values of x from 0 to 5. Microwave dielectric properties such as
and c f showed smooth variation with x , while the unloaded quality factor (Qu)
showed remarkable improvement with x
The paper presents a compact planar Ultra Wide Band ¯lter employing folded stepped
impedance resonators with series capacitors and dumb bell shaped defected ground structures. An
interdigital quarter wavelength coupled line is used for achieving the band pass characteristics. The
transmission zeros are produced by stepped impedance resonators. The ¯lter has steep roll o® rate and
good attenuation in its lower and upper stop bands, contributed by the series capacitor and defected
ground structures respectively.
Description:
Progress In Electromagnetics Research C, Vol. 49, 123{131, 2014
Mathew, K T; Anil, Lonappan; Paul, Benzy; Thimothy, V O; Rajasekaran, C; Vinu, Thomas; Joe, Jacob(Wiley InterScience, January , 2009)
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Abstract:
This article reports a new method of analyzing pericardial
fluid based on the measurement of the dielectric properties at microwave
frequencies. The microwave measurements were performed by
rectangular cavity perturbation method in the S-band of microwave frequency
with the pericardial fluid from healthy persons as well as from
patients suffering from pericardial effusion. It is observed that a remarkable
change in the dielectric properties of patient samples with the
normal healthy samples and these measurements were in good agreement
with clinical analysis. This measurement technique and the method
of extraction of pericardial fluid are simple. These results give light to
an alternative in-vitro method of diagnosing onset pericardial effusion
abnormalities using microwaves without surgical procedure.
The standard separable two dimensional wavelet transform has achieved a great success in image
denoising applications due to its sparse representation of images. However it fails to capture efficiently the
anisotropic geometric structures like edges and contours in images as they intersect too many wavelet basis
functions and lead to a non-sparse representation. In this paper a novel de-noising scheme based on multi
directional and anisotropic wavelet transform called directionlet is presented. The image denoising in
wavelet domain has been extended to the directionlet domain to make the image features to concentrate on
fewer coefficients so that more effective thresholding is possible. The image is first segmented and the
dominant direction of each segment is identified to make a directional map. Then according to the
directional map, the directionlet transform is taken along the dominant direction of the selected segment.
The decomposed images with directional energy are used for scale dependent subband adaptive optimal
threshold computation based on SURE risk. This threshold is then applied to the sub-bands except the LLL
subband. The threshold corrected sub-bands with the unprocessed first sub-band (LLL) are given as input
to the inverse directionlet algorithm for getting the de-noised image. Experimental results show that the
proposed method outperforms the standard wavelet-based denoising methods in terms of numeric and
visual quality
Description:
Signal & Image Processing : An International Journal (SIPIJ) Vol.3, No.6, December 2012
Raveendranath, U; Biju Kumar, S; Mathew, K T(IETE Technical Review, September , 1999)
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Abstract:
The performance of circular, rectangular and cross irises for the coupling of microwave power
to rectangular waveguide cavity resonators is discussed. For the measurement of complex
permittivity of materials using cavity perturbation techniques, rectangular cavities with high
Q-factors are required. Compared to the conventional rectangular and circular irises, the cross Iris
coupling structure provides very high loaded quality factor for all the resonant frequencies. The
proposes cross iris coupling structure enhances the accuracy of complex permittivity measurements.
Saou, Wen Su; Kin, Lu Wong(Microwave and Optical Technology Letters, September 20, 2005)
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Abstract:
novel design of at internal PIFA integrated with an
RF-shielding metal case for application in a clamshell or fielder-tvpe
mobile phone is presented. The integrated PIFA has a bent and tapered
radiating arm in order to easily fit in the casing of the clamshell mobile
phone as an internal antenna. The integrated PlEA can also provide a
wide operating bandwidth fir UM7S (1920-2170 MHz) operation. In
addition, for the clamshell mobile phone in either the talk or standby
condition, only a small effect on the operating bandwidth of the integrated
PIFA is obtained. The experimental results of the proposed design are presented
Haddud,T A; Al-Mansoori,M H; Zamzuri,A K; Shaharudin,S; Abdullah,M K; Mahdi,M A(Microwave and Optical Technology Letters, April 20, 2005)
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Abstract:
In this paper, the generation of a multiwavelength laser
source from a Brillouin -Erbium fiber laser in the long wavelength band
(L-band) region is experimentally demonstrated. The proposed laser
system utilizes a Fabrv-Perot cavity formed by fiber-loop mirrors.
Twenty-four lines of Brillouin-Stokes with line spacings of 10 GHz are
obtained in the L-band region
Anupam,Chandran R; Thomaskutty,Mathew; Aanandan,C K; Mohanan, P; Vasudevan, K(Microwave and Optical Technology Letters, February 5, 2004)
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Abstract:
A novel technique for backscattering reduction for both TE
and TM polarisation, employing a metallo-dielectric structure based on
Sierpinski carpet fractal geometry, is reported. A reduction in backscattered
power of --30 dB is obtained for normal incidence in the X-band for the
structure using the third iterated stage of the fractal geometry
Lethakumary,B; Sreedevi, Menon K; Aanandan,C K; Vasudevan, K; Mohanan, P(Microwave and Optical Technology Letters, July 20, 2004)
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Abstract:
This paper presents the outcome of the experimental studies
performed on L-strip fed compact rectangular microstrip antenna.
The effect of the feed parameters upon the characteristics of the antenna
is studied in detail. The antenna offers an impedance bandwidth of
nearly 20% and is suitable for broadband applications
Sreedevi, Menon K; Lethakumary,B; Bijumon, P V; Sebastian,M T; Mohanan, P(Microwave and Optical Technology Letters, May 5, 2005)
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Abstract:
In this paper, the advantages of using L-shaped microviij)
feed to e.tcite a rectangular dielectric resonator cuuenna (DRA) by elemanagnetic
coupling are presented. This feeding technique enhances the
hardsvidth and gain of the antenna without affecting its size. The experimental
re srdts are validated using Fidelity software based on the finitedifference
tine-domain (FDTD) method
Mridula, S; Jacob,George; Mohanan, P(Microwave and Optical Technology Letters, December 20, 1999)
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Abstract:
A novel antenna configuration comprised of two circular
micro strip antennas (CMAs) resonating in the TMtt and TM2, modes,
producing radiation characteristics suitable for a mobile telephone handset,
is presented. The antennas operating at the same frequency are
placed back to back with a separation comparable to the thickness of a
typical handset. The radiation pattern consists of a region of reduced
radiation intensity, which minimizes the radiation hazards to the user
A novel antenna configuration comprised of two circular
microstrip antennas (CMAs) resonating in the TMtt and TM2, modes,
producing radiation characteristics suitable for a mobile telephone handset,
is presented. The antennas operating at the same frequency are
placed back to back with a separation comparable to the thickness of a
typical handset. The radiation pattern consists of a region of reduced
radiation intensity, which minimizes the radiation hazards to the user
Description:
Microwave and Optical Technology Letters,VOL 23,issue 6.pp 370-372
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.
Zhongyou,Yan(Microwave Engineering Group,Department of Electronics, January 5, 2002)
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Abstract:
patch resonator with a via connecting ground plane is
proposed and studied experimentally. The resonant frequency of this
patch resonator is tunable up to about 34 % by adjusting the via position
in the center line. The lowest resonant frequency of this patch resonator
has been reduced by more than 64% of the same size patch resonator
A microwave dielectric ceramic resonator based on BaCe2Ti5O15 and Ba5Nb4O15 have been prepared by conventional solid state ceramic route. The dielectric resonators (DRs) have high dielectric constant 32 and 40 for BaCe2Ti5O15 and Ba5Nb4O15, respectively. The whispering gallery mode (WGM) technique was employed for the accurate determination of the dielectric properties in the microwave frequency range. The BaCe2Ti5O15 and Ba5Nb4O15 have quality factors (Q X F) of 30,600 and 53,000 respectively. The quality factor is found to depend on the azimuthal mode numbers. The temperature coefficient of resonant frequency (Tr) of BaCe2Ti5O15 and Ba5Nb4O15 have been measured accurately using different
resonant modes and are + 41 and + 78 ppm/K, respectively
The microwave dielectric properties of (I -x)CaTiO3-xSm(Mg1/2Tit,2)O3(0.1 <-x< 1.0) have been investigated. The
system forms a solid solution throughout the entire compositional range. The dielectric constant decreases from 86 to 25 as x
varies from 0.1 to 1.0. The Qxf varies non-linearly and increases for composition with x> 0.6. The nonmonotonic variation
with composition x is more pronounced in Tt than in er. The microwave dielectric properties indicate the possibility of a phase
transformation for x between 0.4 and 0.5