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.
Bijumon, P V; Sreedevi, Menon K; Suma,M N; Sebastian,M T; Mohanan, P(IEE Electronics letters,UK, 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
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
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(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
Biju Kumar, S; Aanandan,C K; Mathew, K T(John Wiley & Sons, October 5, 2001)
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Abstract:
The detection of buried objects using time-domain freespace
measurements was carried out in the near field. The location of a
hidden object was determined from an analysis of the reflected signal.
This method can be extended to detect any number of objects. Measurements
were carried out in the X- and Ku-bands using ordinary rectangular
pyramidal horn antennas of gain 15 dB. The same antenna was
used as the transmitter and recei er. The experimental results were
compared with simulated results by applying the two-dimensional
finite-difference time-domain(FDTD)method, and agree well with each
other. The dispersi e nature of the dielectric medium was considered for
the simulation.
Mridula, S; Sreedevi, Menon K; Mohanan,K; Bijumon, P V(Microwave and Optical Technology Letters, February 20, 2004)
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Abstract:
The radiation characteristics of a microstrip-line-excited rectangular dielectric resonator antenna (DRA) are studied experimentally.The radiation charactristics and excitation of different modes are highly influenced by the orientation of the DR,feed line parameters ,and finite size of the ground plane
Mridula, S; Mohanan, P; Nijas, C M; Dinesh, R; Abdul, Rasheed; Vasudevan, K(IEEE, August 30, 2012)
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Abstract:
A novel compact RFID tag employing open stubs in a
microstrip transmission line is proposed. The prototype of the tag is
fabricated on a substrate of dielectric constant 4.4 and loss tangent 0.0018.
The tag consists of microstrip open stub resonators and cross polarized
transmitting and receiving disc monopole antennas. A prototype of 8 bit
data encoded tag is demonstrated in this communication. Method for
enhancing the performance of the RFID tag is also proposed. Magnitude
or group delay response can be used to decode the tag informations
Description:
Antennas and Propagation, IEEE Transactions on,VOL 60,issue 9,pp 4428-4432
Manju,Paulson; Mohanan, P; Sona,Kundukulam O(Microwave and Optical Technology Letters, September 5, 2000)
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Abstract:
A compact microstrip antenna with circular polarization radiation is demonstrated.A reducation in the required parameters for achieving CP radiation makes the present antenna design simpler
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
Design of a dual-port circular patch antenna with a sector-slot for dual-frequency operation is presented. The antenna resonates at two distinct frequencies with orthogonal polarizations and broad radiation characteristics. Unlike the conventional circular patch, this antenna can be microstrip-fed to operate at either of the resonances. The two polarizations can be simultaneously excited using two electromagnetically coupled ports with an isolation better than −30 dB between the ports. This antenna has the added advantage of size reduction of 44% compared to the conventional circular patch without any reduction in gain.
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
Rohith, Raj K; Sona,Kundukulam O; Aanandan,C K; Vasudevan, K; Mohanan, P; Praveen,Kumar(Microwave and Optical Technology Letters, February 20, 2004)
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Abstract:
compact microstrip antenna integrated with an amplifier
having an area reduction of 70%, compared to the standard circular microstrip
patch antenna, is presented. The antenna also provides an enhanced
gain of 10-dB more than its passive counter part. The measured 2:1
VSWR band width is -4% at 790 MHz, which is 2.5 times larger than that
of the passive microstrip antenna
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.
The design and implementation of a novel asymmetric coplanar
waveguide (ACPW ) band rejection filter using defected ground
structure ( DGS) is presented . The proposed ACPW DGS technology
provides band gap characteristics with only one cell in the lateral
ground plane . The equivalent circuit model of the proposed DGS
unit section is described . Measurements of ACPW DGS showed good
agreement with simulation and the proposed model
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%
A compact Co-Planar Waveguide (CPW) fed antenna operating at 2.4GHz with 300MHz 2:1 VSWR
bandwidth is presented. Compared to a conventional quarter wavelength CPW fed monopole antenna, the aperture
area reduction of the present antenna is 85%. The prototype antenna fabricated on a substrate of εr = 4.4 and
thickness 1.6mm is only 22x10x1.6mm3. This much size reduction and impedance matching is achieved by
adjusting the signal to ground plane separation and meandering the ground plane of a 50Ω CPW transmission line
Description:
General Assembly and Scientific Symposium, 2011 XXXth URSI
Mridula, S; Shameena, V A; Anju, Pradeep; Sarah, Jacob; Lindo, A O; Mohanan, P(Elsevier, March 20, 2011)
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Abstract:
A printed compact coplanar waveguide fed triangular slot antenna for ultra wide band (UWB) communication
systems is presented. The antenna comprises of a triangular slot loaded ground plane with a T
shaped strip radiator to enhance the bandwidth and radiation. This compact antenna has a dimension
of 26mm×26mm when printed on a substrate of dielectric constant 4.4 and thickness 1.6mm. Design
equations are implemented and validated for different substrates. The pulse distortion is insignificant
and is verified by the measured antenna performance with high signal fidelity and virtually steady group
delay. The simulation and experiment reveal that the proposed antenna exhibits good impedance match,
stable radiation patterns and constant gain and group delay over the entire operating band