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ABSTRACT: In this paper, a modified version of the multi-band multiple ring monopole antenna is proposed. The height of the new design which consists of multiple half rings is half of the original one. The modified design is more attractive for low profile applications due to its lower height. The antenna is simulated and measured. It is shown that the simulation and measurement results are in good agreement. The performance of the modified version of the antenna is compared with the original design in terms of input characteristic and far field radiation patterns. It is shown that the multiband behaviour of the modified design is similar to the original one. However, there is a frequency shift between the operating bands of the new and the original antennas. The radiation patterns of the both antennas are similar to the conventional monopole antenna in lower operating frequency bands. However, degradation in radiation patterns of the both antennas is observed as frequency increases.
Progress In Electromagnetics Research C. 01/2010; 14:173-183.
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ABSTRACT: A log periodic dipole array with switching to select sub-bands is presented. Recently we have proposed a 3 to 1 bandwidth reconfigurable printed dipole antenna with harmonic trap. One of the frequency bands can be selected by changing the length of the dipole. In this paper a reconfigurable log periodic printed dipole array (LPDA) is proposed. The frequency bands can be selected by switching the printed dipoles of the LPDA. The flexibility of the reconfigurable LPDA lies in selecting the frequency bands with different bandwidths and directive patterns. This is a significant advantage over reconfigurable printed dipole antenna. The antenna is designed, fabricated and measured. The measurement results show that the reconfigurable LPDA operates over a frequency range of 3:1. The antenna is thus suitable for frequency switching in the FCC ultra wideband allocation.
Wideband, Multiband Antennas and Arrays for Defence or Civil Applications, 2008 Institution of Engineering and Technology Seminar on; 04/2008
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ABSTRACT: In this paper the effects of changing the thickness of the rings and height from the ground on the return loss of the multiple ring monopole antenna are presented. It is experimentally shown that the changing of the thickness of the rings causes a frequency shift at the fourth and the fifth bands but it does not have a significant effect on the lower bands. In addition, better matching at higher frequency bands can be obtained for smaller height from the ground plane but it does not affect on the lower frequency bands
Antennas and Propagation Society International Symposium 2006, IEEE; 08/2006
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Antenna Technology Small Antennas and Novel Metamaterials, 2006 IEEE International Workshop on; 02/2006
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Antenna Technology Small Antennas and Novel Metamaterials, 2006 IEEE International Workshop on; 02/2006
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ABSTRACT: The effects of the ellipticity ratio and the thickness of the rings on the multiple ring monopole antennas are presented. Several multiple ring monopole antennas with different ellipticity ratios and thickness of the rings are designed, fabricated and measured. The results show that the resonance bandwidths can be controlled by the ellipticity ratio and changing the thickness of the rings causes a frequency shift at the fourth band but it does not have a significant effect on the lower bands.
Wideband and Multi-band Antennas and Arrays, 2005. IEE (Ref. No. 2005/11059); 10/2005
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ABSTRACT: A spherical quadrifilar helix antenna (SQHA) is introduced for producing a saddle point shaped radiation pattern. Radiation characteristics of the antenna have been simulated and the results have been compared with the characteristics of the cylindrical quadrifilar helix antenna (CQHA) which was previously used for this purpose. The results show an improvement in radiation pattern of the proposed antenna in comparison with the previous antenna.
Antenna Theory and Techniques, 2003. 4th International Conference on; 10/2003
