Abstract: | Simultaneous elimination of specular reflection and backscattered power from a plane metallic surface by simulated corrugated surfaces of constant period and variable strip width for TM polarisation is reported. This new configuration offers almost a ten-fold frequency bandwidth compared with a regularly spaced strip grating of the same size. |
URI: | http://dyuthi.cusat.ac.in/purl/672 |
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New simulated c ... characteristics Saji@.pdf | (262.5Kb) |
Abstract: | A novel H-shaped patch antenna suitable for wireless and satellite communications is presented. The new antenna has some advantages compared to conventional microstrip patch antennas, such as small size, a fewer number of modes, no harmonic resonance, and the provision of pure reactive impedances at its harmonics that can result in increasing the transmitter efficiency. The basic principles and design procedure are introduced. Two antennas at two different frequencies, 4 and 10 GHz, are designed, fabricated, and measured. The measured results show a good agreement with the predicted ones |
URI: | http://dyuthi.cusat.ac.in/purl/1380 |
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A novel H-shaped patch antenna.PDF | (275.9Kb) |
Abstract: | Photonic band-gap (PBG) structures are utilized in microwave components as filters to suppress unwanted signals. In this work, rectangular perforations were created in the ground plane of a microstrip line to construct a PBG structure. A gold-coated alumina substrate was utilized to switch or tune the bandstop characteristics of this structure. It was demonstrated that the bandstop characteristics were switched off from - 35 to - 1 dB at 16 GHz. Tuning of the bandstop edge with a shift of 1.5 GHz was also shown |
URI: | http://dyuthi.cusat.ac.in/purl/1409 |
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A novel method ... ning of PBG structures.PDF | (561.5Kb) |
Abstract: | HIV/AIDS is one of the most destructive epidemics in ever recorded history claims an estimated 2.4 –3.3 million lives every year. Even though there is no treatment for this pandemic Elisa and Western Blot tests are the only tests currently available for detecting HIV/AIDS. This article proposes a new method of detecting HIV/AIDS based on the measurement of the dielectric properties of blood at the microwave frequencies. The measurements were made at the S-band of microwave frequency using rectangular cavity perturbation technique with the samples of blood from healthy donors as well as from HIV/AIDS patients. An appreciable change is observed in the dielectric properties of patient samples than with the normal healthy samples and these measurements were in good agreement with clinical results. This measurement is an alternative in vitro method of diagnosing HIV/AIDS using microwaves. |
URI: | http://dyuthi.cusat.ac.in/xmlui/purl/2052 |
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A novel method of detecting...pdf | (156.8Kb) |
Abstract: | In this paper, a multiband antenna using a novel fractal design is presented. The antenna structure is formed by inscribing a hexagonal slot within a circle. This base structure is then scaled and arranged within the hexagon along its sides without touching the outer structure. The proposed CPW fed, low profile antenna offers good performance in the 1.65 – 2.59 GHz, 4.16 – 4.52 GHz and 5.54 – 6.42 GHz bands and is suitable for GSM 1800/1900, Bluetooth, IMT advanced systems and upper WLAN applications. The antenna has been fabricated on a substrate of height 1.6 mm and εr = 4.4 and simulation and experimental results are found to be in good agreement |
Description: | RADIOENGINEERING,vol 22,issue 4,pp 1263 |
URI: | http://dyuthi.cusat.ac.in/purl/4330 |
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A Novel Planar ... Multiband Applications.pdf | (3.535Mb) |
Abstract: | An innovative phaseshifterless, wideband, micrustrip leaky-wave antenna with an electronically steerable dual-pencil-beam pattern in the H-plane is presented. The log-periodic geometry of the leaky slots of the antenna results in a wide bandwidth of 25.19%. The Jan beam can he steered up to 14° over the wide resonating band of the anteww. The beam is also steerable at a fixed frequency. by reactivelty loading the slots and a maximum steering angle of about 14° is ohserved. for different capacitor values with an improved bandwidth of 33 _i%. This concept is studied using passive components but it can be extended to varactors |
URI: | http://dyuthi.cusat.ac.in/purl/1418 |
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A novel electro ... dic leaky-wave antenna.PDF | (931.7Kb) |
Abstract: | A navel ultra-thin radar-absorbing material (RAM) using metanwterials is presented and the absorption performance is examined. Due to the high-impedance property of the metamalerials. the thickness of the RAM is about several tenths of the center wavelength of the absorption band, which is considerably thinner than conventional absorbers. The absorption bandwidth of the RAM is about several hundred megahertz |
URI: | http://dyuthi.cusat.ac.in/purl/1417 |
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A novel radar-a ... based on EBG structure.PDF | (907.3Kb) |
Abstract: | Design, development and experimental observations of a L: band printed dipole antenna is presented.Bandwidth enhancement is achieved by end-loading or the dipole arms. Using the present technique Impedance bandwidth van be enhanced up to 50% without degrading the efficiency of the antenna. |
URI: | http://dyuthi.cusat.ac.in/purl/1435 |
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Novel wide band printed dipole antenna.PDF | (1.287Mb) |
Abstract: | A dual port dual polarized octagonal microstrip patch antenna suitable for dual band applications is discussed theoretically and experimentally. The antenna exhibits good impedance bandwidth, gain and broad radiation patterns. Parameters predicted by the Conformal Finite Difference Time Domain algorithm show good agreement with the simulated results and experimental observations |
Description: | Proc. XXVIII URSI General Assembly |
URI: | http://dyuthi.cusat.ac.in/purl/4337 |
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Octagonal Micro ... Dual Band Applications.pdf | (878.3Kb) |
Abstract: | The paper proposes an octagon shaped Microstrip Patch Antenna suitable for dual band applications. The striking features of this compact, planar antenna are sufficient isolation between the two operating bands and an area reduction of - 29% in comparison to a conventional circular patch antenna operating in the same band |
Description: | Antennas and Propagation Society International Symposium, 2002. IEEE |
URI: | http://dyuthi.cusat.ac.in/purl/4328 |
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Octagon Shaped ... Dual Band Applications.pdf | (161.2Kb) |
Abstract: | This paper reports a novel region-based shape descriptor based on orthogonal Legendre moments. The preprocessing steps for invariance improvement of the proposed Improved Legendre Moment Descriptor (ILMD) are discussed. The performance of the ILMD is compared to the MPEG-7 approved region shape descriptor, angular radial transformation descriptor (ARTD), and the widely used Zernike moment descriptor (ZMD). Set B of the MPEG-7 CE-1 contour database and all the datasets of the MPEG-7 CE-2 region database were used for experimental validation. The average normalized modified retrieval rate (ANMRR) and precision- recall pair were employed for benchmarking the performance of the candidate descriptors. The ILMD has lower ANMRR values than ARTD for most of the datasets, and ARTD has a lower value compared to ZMD. This indicates that overall performance of the ILMD is better than that of ARTD and ZMD. This result is confirmed by the precision-recall test where ILMD was found to have better precision rates for most of the datasets tested. Besides retrieval accuracy, ILMD is more compact than ARTD and ZMD. The descriptor proposed is useful as a generic shape descriptor for content-based image retrieval (CBIR) applications |
Description: | Pattern Recognition and Image Analysis, 2008, Vol. 18, No. 1, pp. 23–29 |
URI: | http://dyuthi.cusat.ac.in/purl/4570 |
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Performance Stu ... Based Shape Descriptor.pdf | (230.2Kb) |
Abstract: | A forward - biased point contact germanium signal diode placed inside a waveguide section along the E -vector is found to introduce significant phase shift of microwave signals . The usefulness of the arrangement as a phase modulator for microwave carriers is demonstrated. While there is a less significant amplitude modulation accompanying phase modulation , the insertion losses are found to be negligible. The observations can be explained on the basis of the capacitance variation of the barrier layer with forward current in the diode |
URI: | http://dyuthi.cusat.ac.in/purl/1432 |
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Phase modulatio ... ermanium signal diodes.PDF | (882.1Kb) |
Abstract: | An electrically small, broadband-modified, truncated ground metamaterial EZ antenna is presented. This, a modified EZ antenna system, achieves a larger bandwidth of the order of 650 MHz by adjusting the metamaterial-inspired meandered ground element fed by a top loaded monopole. The design is devoid of the large ground planes and the external parasitic elements used in conventional designs for achieving proper impedance matching characteristics. The antenna requires a small foot print of kg/5 3 kg/10, where kg is the guided wavelength corresponding to the lowest frequency of operation, when printed on a substrate of dielectric constant 4.4 and thickness 1.6 mm. The antenna offers a 2:1 VSWR bandwidth from 750 MHz to 1.4 GHz, which covers CDMA, GSM, and ISM bands |
Description: | MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 56, No. 3, March 2014 |
URI: | http://dyuthi.cusat.ac.in/purl/4339 |
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A Planar Compac ... ired Broadband Antenna.pdf | (567.7Kb) |
Abstract: | A broadband rectangular tnicrostrip antenna utilizing an electromagnetically coupled L-strip feed is presented. Experimental study shows a 2:1 VSWR bandwidth of a 10% and excellent cross-polarization performance with a radiation coverage almost as same as that of the rectangular microstrip antenna fed by conventional methods. The variation of bandwidth for different feed parameters is also studied. The proposed antenna is suitable for broadband communications |
URI: | http://dyuthi.cusat.ac.in/purl/1385 |
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PLANAR L-STRIP ... AND MICROSTRIP ANTENNA.PDF | (716.7Kb) |
Abstract: | A compact coplanar waveguide-fed (CPW) monopole antenna for ultra-wideband wireless communication is presented. The proposed antenna comprises of a CPW-fed beveled rectangular patch with a modified slotted ground. The overall size of the antenna is 30 mm 27 mm 1.6 mm. The lower edge of the band is attained by properly decoupling the resonant frequencies due to the extended ground plane and the beveled rectangular patch of the antenna. The upper edge of the radiating band is enhanced by beveling the ground plane corners near the feed point. Experimental results show that the designed antenna operates in the 2.7–12 GHz band, for S11 10 dB with a gain of 2.7–5 dBi. Both the frequency domain and time domain characteristics of the antenna are investigated using antenna transfer function. It is observed that the antenna exhibits identical radiation patterns and reasonable transient characteristics over the entire operating band |
Description: | International Journal of RF and Microwave Computer‐Aided Engineering,VOL 22,issue 5,pp 594-602 |
URI: | http://dyuthi.cusat.ac.in/purl/4331 |
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Planar UWB Ante ... d Slotted Ground Plane.pdf | (963.2Kb) |
Abstract: | Two three-clement polarisation-agile active microstrip patch arrays have been developed . The radiating elements are square patches each with two transistors mounted on adjacent edges. The patches radiate orthogonal modes , the relative phase of which can be varied. Radiation patterns show good agreement with predictions from theory, in both linear and circular polarization, and no grating lobes were observed |
URI: | http://dyuthi.cusat.ac.in/purl/1349 |
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Polarisation ag ... icrostrip patch arrays.PDF | (173.6Kb) |
Abstract: | A new microstrip antenna element is described which exhibits polarization agility. This is achieved by employing a T-slot radiator which is driven by the edge fields of a balanced microstrip line. The balanced line can support two propagating modes. namely. an even mode and an odd mode, and be switching between these modes. the orthogonal arms of the T-slot radiator are separately excited thus forming orthogonally polarized radiated fields. A nucrostrip patch antenna, which displays polarization agility using the sane mechanism, is also described |
URI: | http://dyuthi.cusat.ac.in/purl/1364 |
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POLARIZATION AG ... ARRAY ANTENNA ELEMENT.PDF | (638.8Kb) |
Abstract: | A fairly rigorous analytical treatment of the power characteristics of dielectric optical waveguides with Piet Hein core-cross sectional geometry is presented in this paper. This kind of wareguide structure would be advantageous owing to the absence of corners, which are found in rectangular guides, resulting in undesirable loss (hit to the scattering of light. In order to simplify this theoretical approach. em approximation of vanishing refractive index difference between the guiding and the non-guiding sections is implemented. The variation eJ logarithmic power is shown for different dimensions of the core, corresponding to different azimuthal modal indices. It is found that the nutlet with higher index values carry less logaritlunic power in the lower tail of the propagation 's constant range, and this feature affects the higher tail. A better kind of uniformity of the power distribution is observed near the higher tail of the range of propagation Constants |
URI: | http://dyuthi.cusat.ac.in/purl/1396 |
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Power character ... l piet hein waveguides.PDF | (136.2Kb) |
Abstract: | Ceramics of composition BaO-Ln2O3-STiO2 have been prepared with four elements (Ln=La,Pr,Nd.Sm) by a conventional solid state ceramic preparation route and the dielectric properties measured in the microwave frequency range |
URI: | http://dyuthi.cusat.ac.in/purl/1439 |
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Dielectric reso ... (Ln = La, Pr, Nd, Sm).PDF | (3.733Mb) |
Abstract: | The dielectric ceramics BaNd2Ti3Oto, BaNd2Ti4O12 and BaNd2Ti5O14 have been prepared by Conventional solid state ceramic route. The sintered ceramic samples have been characterized by X-ray diffraction and Scanning Electron Microscopy (SEM). The dielectric properties in the microwave frequency range have been measured using conventional microwave dielectric resonator methods. The BaNd2Ti1O10, BaN2Ti4O12 and BaNd2Ti5O14 have dielectric constants (Er) ~ 60, 84 and 77 respectively. They have relatively high quality factors |
URI: | http://dyuthi.cusat.ac.in/purl/1444 |
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Preparation,cha ... BaO-Nd2O3-TiO2 system.PDF | (2.220Mb) |
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