| 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 |
| URI: | http://dyuthi.cusat.ac.in/purl/1369 |
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| Microstrip ante ... uced radiation hazards.PDF | (1.152Mb) |
| 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. |
| URI: | http://dyuthi.cusat.ac.in/purl/2721 |
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| Dyuthi-P00358.pdf | (225.0Kb) |
| Abstract: | 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 |
| URI: | http://dyuthi.cusat.ac.in/purl/1446 |
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| Microwave chara ... ng gallery mode method.PDF | (2.989Mb) |
| Abstract: | 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 |
| URI: | http://dyuthi.cusat.ac.in/purl/1453 |
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| Microwave diele ... 3 [0. 1 _x 1] ceramics.PDF | (2.946Mb) |
| Abstract: | microwave dielectric properties of ceramics based on Ba(Mgv3Ta(2-2x)t3W,t3Tixt3)O3 is investigated as a function of x. The 15 densification as well as dielectric properties deteriorate with increase in the substitution levels of (Ti 1,3W113)333 + at (Ta213)3.33+ site 16 in Ba(Mg113Ta213)03. The rt is approaching zero between x = 0.1 and 0.15 in Ba(Mg it3Ta(2-2,,.)t3W,it3Ti,Tt3)O3 where quality factor is 17 reasonably good (Qu x f = 80,000-90,000 GHz). The Ba(Mg1,3Ta(2_,013W,13Ti,,13)03 with x = 1.0 has e, = 15.4, rf= -25.1 ppm/ 18 "C, Q„ x f = 35,400 GHz |
| URI: | http://dyuthi.cusat.ac.in/purl/1488 |
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| Microwave diele ... 3Wx3Tixf3) 03 ceramics.PDF | (3.228Mb) |
| Abstract: | The BaO-2CeO2-nTiO2 ceramics with n = 3, 4 and 5 have been prepared with CeO2 as starting material . The ceramics have been characterized using scanning electron microscopy , X-ray diffraction , Raman and X-ray photoelectron spectroscopy techniques. The microwave dielectric properties have been measured using standard dielectric resonator techniques . BaO-2CeO2-3TiO2 (123), BaO-2CeO2-4TiO2 ( 124) and BaO-2CeO2-5TiO2 ( 125) ceramics showed dielectric constants of 38, 27 and 32, respectively . All the ceramics showed fairly good unloaded Q - factors . 124 and 125 compounds exhibited low tf values, while 123 showed a high rf value |
| URI: | http://dyuthi.cusat.ac.in/purl/1493 |
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| Microwave diele ... -2CeO2-nTiO2 ceramics.PDF | (3.306Mb) |
| Abstract: | Dielectric resonator ceramics with composition formula Ba[(D3+0.3 Bi0.2)Nb0.5]O3,where D3+=Y,Pr,Sm,Gd,Dy and Er,were prepared by the conventional ceramic preparation route |
| URI: | http://dyuthi.cusat.ac.in/purl/1441 |
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| Microwave diele ... Y, Pr, Sm, Gd, Dy, Er).PDF | (2.529Mb) |
| Abstract: | A circular miqrostrip antenna with a modified structure is presented. By adjusting the feed location along the circumference of the patch it is possible to match the antenna with a C microstrip line of any impedance. The impedance bandwidth and radiation characteristics are unaffected by this structural V modification. |
| URI: | http://dyuthi.cusat.ac.in/purl/674 |
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| Modified circular patch antenna Dey.pdf | (199.5Kb) |
| Abstract: | A simple technique to improve the impedance bandwidth of a circular microstrip patch antenna using two sectorial slots is proposed. Using this design more than 5% impedance bandwidth is obtained. The added advantage of this new antenna is that it can be fed by a 50 microstrip line. |
| URI: | http://dyuthi.cusat.ac.in/jspui/handle/dyuthi/1558 |
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| A new broadband circular patch antenna.PDF | (1.429Mb) |
| Abstract: | A simple technique to improve the impedance bandwidth of a circular microstrip patch antenna using two sectorial slots is proposed. Using this design more than 5% impedance bandwidth is obtained. The added advantage of this new antenna is that it can be fed by a 50- microstrip line |
| URI: | http://dyuthi.cusat.ac.in/purl/1366 |
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| A new broadband circular patch antenna.PDF | (1.429Mb) |
| Abstract: | A new compact dual-band, dual-polarized microstrip antenna is presented. 7'iris antenna resonates at two frequencies with different polarizations: a linearly polarized one for terrestrial communication, and a circularly polarized one for satellite mobile communication. This antenna also provides an area reduction of 70% compared to a standard rectangular patch antenna |
| URI: | http://dyuthi.cusat.ac.in/purl/1376 |
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| A new compact d ... zed microstrip antenna.PDF | (1.044Mb) |
| Abstract: | A new microstrip antenna geometry with considerable reduction in size, with similar radiation characteristics to those of an equivalent rectangular patch antenna is proposed. A relationship has been suggested for fmding out the resonant frequency of the new geometry, and its validity has been established by the experimental results. Without increasing the aperture area, this geometry also offers a facility for considerably reducing the resonant frequency compared to conventional patches. |
| URI: | http://dyuthi.cusat.ac.in/purl/673 |
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| New compact microstrip antenna Jacob.pdf | (248.7Kb) |
| Abstract: | New dielectric ceramics with formula BaTi3Nb4, O„ and Ba6Til4Nbz039 have been prepared and characterized. BaTi3Nba017 was densified to 92% of TD after firing at 1310 oC for 4 h. However, Ba6Ti 1 4Nb2O39 fired under optimized conditions (1260 ` C for 4 h) showed only 85% TD together with secondary phase. The crystal system of both of the compositions is orthorhombic |
| URI: | http://dyuthi.cusat.ac.in/purl/1443 |
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| New high permit ... TiO2-Nb2O5 composition.PDF | (2.094Mb) |
| Abstract: | compact multihand planar octagonal-shaped microstrip antenna simultaneously suitable for mobile communication and blue tooth application is presented. The antenna provides sufficient isolation benveen the two operating bands and an area reduction of -29 % with respect to a circular patch operating in the same band |
| URI: | http://dyuthi.cusat.ac.in/purl/1384 |
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| A NEW MICROSTRI ... BLUETOOTH APPLICATIONS.PDF | (1.532Mb) |
| 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: | 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: | 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) |
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