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Search Results: 1 - 10 of 35333 matches for " Anurag Mishra;Prabhakar Singh;Nagendra Prasad Yadav;Jamshed Aslam Ansari;Babau Ram Vishvakarma "
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Compact Shorted Microstrip Patch Antenna for Dual Band Operation
Anurag Mishra;Prabhakar Singh;Nagendra Prasad Yadav;Jamshed Aslam Ansari;Babau Ram Vishvakarma
PIER C , 2009, DOI: 10.2528/PIERC09071007
Abstract: In the present paper notch loaded shorted microstrip patch antenna has been analysed using cavity model. The proposed antenna shows dual band operation which depends on notch dimensions as well as shorting wall. The frequency ratio is found to be 1.5278 for the notch loaded rectangular patch, while in notch loaded shorted patch, the frequency ratio varies from 2.9764 to 2.725 for increasing value of notch width and it is almost invariant with notch depth. Further a slot loaded shorted patch antenna shows the dual frequency nature with the frequency ratio1.7. The theoretical results are compared with IE3D simulation as well as reported experimental results.
Analysis of Shorting Pin Loaded Half Disk Patch Antenna for Wideband Operation
Jamshed Aslam Ansari;Prabhakar Singh;Nagendra Prasad Yadav;Babau Ram Vishvakarma
PIER C , 2009, DOI: 10.2528/PIERC09011203
Abstract: In the present paper the analysis of notch loaded shorted half disk patch is given. It is found that the bandwidth of the antenna depends inversely on the notch width whereas it is invariant with the notch length. Further antenna shows dual band behavior for a gap spacing below 7.5 mm in the gap coupled half disk shorted patch whereas it behaves as a wideband antenna for gap spacing more than 7.5 mm. Theoretical results are compared with simulated and experimental results.
Compact Half U-Slot Loaded Shorted Rectangular Patch Antenna for Broadband Operation
Jamshed Aslam Ansari;Nagendra Prasad Yadav;Prabhakar Singh;Anurag Mishra
PIER M , 2009, DOI: 10.2528/PIERM09090102
Abstract: In this paper, analysis of half U-slot loaded patch antenna with shorting wall is presented. The parameters of the antenna significantly depend on slot and notch dimensions. Bandwidth of the proposed antenna is found to be 21.59%. The 3dB beamwidth of the antenna is found to be 90 at the central frequency of 2.6 GHz. The theoretical results are compared with IE3D simulated and experimental ones which are in good agreement.
Half U-Slot Loaded Semicircular Disk Patch Antenna for GSM Mobile Phone and Optical Communications
Jamshed Aslam Ansari;Anurag Mishra;Babau Ram Vishvakarma
PIER C , 2011, DOI: 10.2528/PIERC10100704
Abstract: In the present paper a dual frequency resonance antenna is achieved by introducing half U-shaped slot in semicircular disk. It is analysed by using circuit theory concept. The resonance frequency is found to be 1.50 GHz and 2.32 GHz, and the bandwidth of the proposed antenna for lower and upper resonance frequency is found to be 5.96% and 11.08% respectively. It is found that the resonance frequency depends inversely on the slot length and feed point, while it increases with increasing the slot width and coaxial probe feed radius. The frequency ratio is found to be 1.54. The theoretical results are compared with IE3D simulation as well as reported experimental results, and they are in good agreement.
H- Shaped Stacked Patch Antenna for Dual Band Operation
Jamshed Aslam Ansari;Prabhakar Singh;Satya Kesh Dubey;Rahmat Ullah Khan;Babau Ram Vishvakarma
PIER B , 2008, DOI: 10.2528/PIERB08031203
Abstract: Analysis of U-slot loaded patch stacked with H-shaped parasitic elements is given in this paper. It is found that the antenna exhibits dual resonance and both the resonance frequency (upper and lower) depends directly on slot width and inversely on slot length. Both upper and lower resonance frequency increase with increasing the value of . Typically the bandwidth at lower and upper resonance is found 3.66% and 10.25% respectively. The radiated power at higher frequency (beamwidth 64) is 0.73 dB as compared to lower resonance frequency (beamwidth 71). The theoretical results are compared with the simulated data obtained from IE3D.
Analysis of a Gap-Coupled Stacked Annular Ring Microstrip Antenna
Jamshed Aslam Ansari;Ram Brij Ram;Prabhakar Singh
PIER B , 2008, DOI: 10.2528/PIERB08011103
Abstract: A theoretical analysis of a gap-coupled stacked annular ringmicrostrip antenna with superstrate is performed in order to obtain wider bandwidth operation. The effects of air gap, superstrate thickness and feedingp oint location on the antenna performance are analyzed in TM mode usingequiv alent circuit concept. It is noted that the proposed antenna is very sensitive to the feedingp oint location in TM mode while annular ringmicrostrip patch antenna is independent of feed point in that mode. The optimized proposed antenna shows an impedance bandwidth of 13.96% whereas the antenna without air-gap has 8.75% bandwidth and without superstrate it has bandwidth of 10.89%. The theoretical results are compared with simulated and experimental results.
E-Shaped Patch Symmetrically Loaded with Tunnel Diodes for Frequency Agile/Broadband Operation
Jamshed Aslam Ansari;Ram Brij Ram
PIER B , 2008, DOI: 10.2528/PIERB07101202
Abstract: Analysis of a frequency agile broadband E-shaped patch antenna (ESPA) symmetrically loaded with tunnel diodes is presented in this paper. The notch parameters such as notch-length, notch-width and position are optimized to achieve the optimum broadband operation of ESPA. Under the optimum conditions of ESPA (bandwidth 32.35%), the performance of the antenna is also analyzed as a function of bias voltage of tunnel diode. It may be mentioned that the proposed antenna can be operated in tunable band that varies from 1055 MHz (bandwidth 42.54%) to 1324 MHz (bandwidth 49.77%) with the bias voltage. Further, the radiated power of the proposed antenna is enhanced by 5.67 dB as compared to the E-shaped patch antenna.
Broadband Stacked U-Slot Microstrip Patch Antenna
Jamshed Aslam Ansari;Ram Brij Ram
PIER Letters , 2008, DOI: 10.2528/PIERL08042102
Abstract: A broadband stacked U-slot microstrip patch antenna is presented using circuit theory concept. The antenna shows two resonance frequencies that are very closely spaced to give broadband characteristics. The frequency band of 186MHz (36.4% impedance bandwidth) is achieved for the proposed antenna. The theoretical results are in good agreement with the simulated results.
Tunnel Diode Integrated E-Shaped Patch Antenna for Broadband Operation
Jamshed Aslam Ansari;Ram Brij Ram
PIER Letters , 2008, DOI: 10.2528/PIERL07121201
Abstract: A tunnel diode integrated E-shaped patch antenna is proposed and analyzed using equivalent circuit concept. It is found that bias voltage of tunnel diode controls the performance of the antenna. Various tunable frequency bands are obtained by selecting suitable bias voltage while antenna topology remains unchanged. Bandwidth of the tunnel diode integrated patch improves to 40.26% over the 32.58% bandwidth of the patch. The radiation pattern also varies with bias voltage and a considerable improvement in beamwidth is observed however radiated power remains almost same.
Comparative study of solar cycles 22 to 24 in relation to solar output variability  [PDF]
Sham Singh, Divya Shrivastava, Shri Ram Lahauriya, Adya Prasad Mishra
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.46048
Abstract: The rate of increase in solar activity at the initiation of solar cycle 22 had led the activity during the solar maximum years 1990-1991, be the most severe of any period during the space age. Solar cycle 23 started in May 1996 and ended in December 2008. Total time period of this solar cycle is 12.6 years. The maximum smoothed sunspot number observed during the solar cycle was 120.8 and minimum was 1.7. It is apparent that solar cycle 23 is a long one. Solar cycle 24 (initiated in December 2008) seems to be weak, which will have a slow ramp up, much slower than the late 19th century cycles used for comparison. In the present work, we have considered Sunspot number (Rz) as an index of solar activity, which shows a predominant 11 year cycle. The strength of the solar cycle makes a huge difference to satellite operators. Each solar peak heats and expands the outer atmosphere. The strength of the solar-cycle length, annual average and temperature correlation enables solar cycle length to be used as a climate predictor tool.
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