International Journal of Advances in Engineering & Technology, May 2011. ©IJAET
ISSN: 2231-1963
• As compared to a circular disk, the angular ring has less stored energy and thus a lower ‘Q’ factor. This implies a wider bandwidth for the antenna.
• Finally, it has been found that, by operating in one of the higher- order broadside mode, i.e. TM, the impedance bandwidth is several times larger than is achievable in other patch of comparable dielectric thickness.
The antenna is designed using transmission and cavity model approach. The details of the designing are given in section III. Section IV shows the even and odd mode technique used for the analysis of gap-coupled antennas. Using this technique, the proposed design for calculating the impedance of gap coupled ARMSA is given in section V. Section VI shows the results and discussion and the conclusion is given in section VII.
2. Theoretical considerations
Microstrip antennas have a number of useful properties, but one of the serious limitations of these antennas has been their narrow bandwidth characteristics. Researchers have been engaged in removing this limitation for the past 20 years, and have been successful in achieving an improved impedance bandwidth for different antennas. Since many wide-band applications require a low-profile conformal antenna, much work has gone into designing wide-band MSA elements or producing MSAs with a dual resonance characteristic. The philosophy behind this technique is that if the resonant frequency of the coupled element or elements is slightly different to that of the driven patch, then the bandwidth of the entire antenna may be increased. The Gap coupled ARMSA can be represented as the two parallel microstrip lines as shown in figure 1 and 2.
Gap Coupled ARMSA Substrate
Ground Plane Figure1: Side view of the gap-coupled ARMSA
DC Reverse
b1 a2 a1 x b2 Feed Point Figure2: Top view of the gap-coupled ARMSA
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