Mohanan,P; Aanandan,C K; K G Nair(Indian Journal of Radio & Space Physics, February , 1984)
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Abstract:
A modified H-plane sectoral horn antenna with identical E- and'H- plane.patterns over the X-band frequency is discussed.
This system has significantly reduced side lobes and hack lobes. Half=power beam width and gain of the antenna are also
improved with enhanced matching , Experimental results for a number of horns with various flanges are presented . These find
practical application for illuminating symmetric antennas like paraboloids and polarization measurements in radio
astronomy, etc. Compared to the fixed pyramidal horns. the present system offers great convenience in trimming the antenna
characteristics
Mohanan,P; Pravinkumar,P A; K G Nair(Indian Journal of Radio & Space Physics, 1982)
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Abstract:
A simple technique for obtaining identical E- and H-plane patterns from E-plane sectoral feed horn is presented. Halfpower
beam width and gain of the antenna are also improved considerably. Experimental results for a number of horns with
flanges of various parameters are also presented. This system may find practical application in radar and space communication
systems
Aanandan,C K; Mohanan,P; K G Nair(Department of Electronics, October , 1992)
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Abstract:
Reduction of radar cross -section of dihedral corner reflectors using
simulated corrugated surface (SCS) is reported. The technique is
found to be more effective in the reduction of RCS or corner reflectors
for normal incidence . A typical reduction of 40-50 dB is
achieved using this method.
Ajaikumar,V; Jose,K A; Aanandan,C K; Mohanan,P; K G Nair(Microwave and Optical Technology Letters, October , 1992)
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[-]
Abstract:
Reduction of radar cross -section of dihedral corner reflectors using
simulated corrugated surface (.SCS) is reported. This technique is
found lo be more effective in the reduction of RCS or corner reflectors
for normal incidence . A typical reduction of 40-50 dB is
achieved using this method
K G Nair; Aanandan,C K; Mohanan,P(Department of Electronics, October , 1992)
[+]
[-]
Abstract:
Reduction of radar cross -section of dihedral corner reflectors using
simulated corrugated surface (SCS) is reported. The technique is
found to be more effective in the reduction of RCS or corner reflectors
for normal incidence . A typical reduction of 40-50 dB is
achieved using this method.
Mohanan,P; Aanandan,C K; K G Nair(Department of Electronics, October , 1992)
[+]
[-]
Abstract:
Reduction of radar cross -section of dihedral corner reflectors using
simulated corrugated surface (SCS) is reported. The technique is
found to be more effective in the reduction of RCS or corner reflectors
for normal incidence . A typical reduction of 40-50 dB is
achieved using this method.
A new microwave dielectric resonator Ba(Tb1/2Nb1/2)03 has been prepared and characterized in the microwave frequency region. 1 wt% CeO2 is used as additive to reduce the sintering temperature. The sintered samples were characterized by XRD, SEM and Raman spectroscopic methods. Microwave DR properties such as er, Q factor and temperature-coefficient of resonant frequency (Ti) have been measured using a HP 8510 B Network Analyzer. Cylindrical DRs of Ba(Tb1/2Nbi/2)03 showed high Er (~ 37), high Q (~3,200) and low Tf (~10 ppm /°C) at 4 GHz and hence are useful for practical applications
Mathew, K T; Robin, Augustine; Ullas G, Kalappura(Wiley InterScience, November , 2008)
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Abstract:
Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) bioceramic and
chitosan (poly [( -1-4) D-glucosamine]) biopolymer show good biocompatibility
in vivo. They have biological origin and show excellent interactions
with microwave. Microwave study of HAp made using different
drying techniques and their composites with chitosan in the ISM band is
presented. Pastes are made using HAp and chitosan with different ratios
of mixing. The dielectric properties of this composites match with that of
human fat, collagen tissues. Some of the compositions exhibit dielectric
property close to that of natural bone. This makes them more
biocompatible and better substitutes for natural bone. Thus composite
bioceramics can be considered as phantom model constituents for
imaging purposes. Their dielectric properties prove that they are
biocompatible.
Raveendranath, U; Bijukumar, S; Mathew, K T(IEEE, December , 2000)
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Abstract:
A novel cavity perturbation technique using coaxial cavity resonators for the measurement of complex permittivity of liquids is presented. The method employs two types of resonators (Resonator I and Resonator II). Resonator I operates in the frequency range 600 MHz-7 GHz and resonator II operates in the frequency range 4 GHz-14 GHz. The introduction of the capillary tube filled with the sample liquid into the coaxial resonator causes shifts in the resonance frequency and loaded Q-factor of the resonator. The shifts in the resonance frequency and loaded Q-factor are used to determine the real and imaginary parts of the complex permittivity of the sample liquid, respectively. Using this technique, the dielectric parameters of water and nitrobenzene are measured. The results are compared with those obtained using other standard methods. The sources of errors are analyzed.
Mohanan,P; Bijumon,P V; Menon,S K; Suma,M N; Sebastian,M T(Department of Electronics, March 31, 2005)
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Abstract:
The impedance bandwidth of a high permittivity cylindrical dielectric
resonator antenna excited by a micro strip line was significantly
improved by modifying the feed geometry. The 10 dB return loss
bandwidth is enhanced from 12 to 26% without much affecting the
gain and other radiation properties of the antenna. Good agreement
has been observed between the predicted and measured results
The impedance bandwidth of a high permittivity cylindrical dielectric
resonator antenna excited by a micro strip line was significantly
improved by modifying the feed geometry. The 10 dB return loss
bandwidth is enhanced from 12 to 26% without much affecting the
gain and other radiation properties of the antenna. Good agreement
has been observed between the predicted and measured results
Mohanan,P; Aanandan,C K; K G Nair; Deepukumar,M; George,J(Department of Electronics, August 15, 1996)
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Abstract:
A new dual port microstrip antenna geometry for dual frequency
operation is presented. The structure consists of the intersection
of two circles of the same radius with their centres displaced by a
small fraction of the wavelength . This antenna provides wide
impedance bandwidth and excellent isolation between its ports.
The gain of the antenna is comparable to that of a standard
circular microstrip antenna operating at the same resonant
frequency. A theoretical analysis for calculating the resonant
frequencies of the two ports is also presented
Deepukumar,M; George,J; Aanandan,C K; Mohanan,P; K G Nair(IEE Electronics letters,UK, June 19, 1996)
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Abstract:
A new dual port microstrip antenna geometry for dual frequency
operation is presented. The structure consists of the intersection
of two circles of the same radius with their centres displaced by a
small fraction of the wavelength . This antenna provides wide
impedance bandwidth and excellent isolation between its ports.
The gain of the antenna is comparable to that of a standard
circular microstrip antenna operating at the same resonant
frequency. A theoretical analysis for calculating the resonant
frequencies of the two ports is also presented
Aanandan,C K; Mohanan,P; K G Nair; Deepukumar,M; George,J(Department of Electronics, August 15, 1996)
[+]
[-]
Abstract:
A new dual port microstrip antenna geometry for dual frequency
operation is presented. The structure consists of the intersection
of two circles of the same radius with their centres displaced by a
small fraction of the wavelength . This antenna provides wide
impedance bandwidth and excellent isolation between its ports.
The gain of the antenna is comparable to that of a standard
circular microstrip antenna operating at the same resonant
frequency. A theoretical analysis for calculating the resonant
frequencies of the two ports is also presented
K G Nair; Aanandan,C K; Mohanan,P; Deepukumar,M; George,J(Department of Electronics, August 15, 1996)
[+]
[-]
Abstract:
A new dual port microstrip antenna geometry for dual frequency
operation is presented. The structure consists of the intersection
of two circles of the same radius with their centres displaced by a
small fraction of the wavelength . This antenna provides wide
impedance bandwidth and excellent isolation between its ports.
The gain of the antenna is comparable to that of a standard
circular microstrip antenna operating at the same resonant
frequency. A theoretical analysis for calculating the resonant
frequencies of the two ports is also presented
K G Nair; Aanandan,C K; Mohanan,P(Department of Electronics, 1990)
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Abstract:
A microstrip antenna with large bandwidth is developed
using a parasitic technique. Compared to the available wide-band antenaas,
the proposed antenna structure Is very compact and gives a less
distorted radiation pattern with frequency . An impedance bandwidth,
eight times that of a conventional patch antenna of the same size, Is
achieved. The concept of coupled microstrip line model is extended for
theoretical interpretation of the impedance Loci
Mohanan,P; Aanandan,C K; K G Nair(Department of Electronics, 1990)
[+]
[-]
Abstract:
A microstrip antenna with large bandwidth is developed
using a parasitic technique. Compared to the available wide-band antenaas,
the proposed antenna structure Is very compact and gives a less
distorted radiation pattern with frequency . An impedance bandwidth,
eight times that of a conventional patch antenna of the same size, Is
achieved. The concept of coupled microstrip line model is extended for
theoretical interpretation of the impedance Loci
Aanandan,C K; K G Nair; Mohanan,P(Department of Electronics, October , 1990)
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[-]
Abstract:
A microstrip antenna with large bandwidth is developed
using a parasitic technique. Compared to the available wide-band antenaas,
the proposed antenna structure Is very compact and gives a less
distorted radiation pattern with frequency . An impedance bandwidth,
eight times that of a conventional patch antenna of the same size, Is
achieved. The concept of coupled microstrip line model is extended for
theoretical interpretation of the impedance loci
Aanandan,C K; Mohanan,P; K G Nair(IEEE Journals/ Transactions (USA), 1990)
[+]
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Abstract:
A microstrip antenna with large bandwidth is developed
using a parasitic technique . Compared to the available
wide-baud antennas,the proposed antenna structure is very
compact and gives a lessdistorted radiation pattern with frequency .
An impedance bandwidth,eight times that of a conventional patch
antenna of the same size, Isachieved. The concept of coupled microstrip
line model Is extended fortheoretical interpretation of the impedance loci
Wang,Wel; Sheng,Bing Chen; Shun,Shi Zhong(Microwave and Optical Technology Letters, October 20, 2004)
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Abstract:
A novel slope -strip feeding technique for a microstrip
antenna is presented in order to achieve a broad bandwidth. The experimental
results show that the optimal bandwidth attained is 53.4% for
less than -10-dB return loss