Dr.B. Suryakanth, Dr.S. N. Mulgi
This paper presents the experimental investigations carried out for obtaining dual band operation of rectangular microstrip antenna by using aperture coupled feeding technique. The antenna resonates for two resonant frequencies at 11.36 GHz and 14.26 GHz with minimum return losses of –22.97 dB and –22.24 dB respectively. The antenna operates at two bands BW2 and BW3. These two bands are due to independent resonance of patch and double U-slots which are excited through H-coupling aperture. The lower resonant frequency f1 is the fundamental resonance of the rectangular patch. The second resonant frequency f2 is due to current along the edges of double U-slots of aperture coupled double U-slot rectangular microstrip antenna (ADUSRMSA). The impedance bandwidths of BW2 and BW3 are found to be 23.87 % and 21.68 % respectively. This technique also enhances the gain to 6.31 dB which is 1.19 times more than the gain of conventional rectangular microstrip antenna (CRMA) and minimizes the cross polar power level to -10.14 dB down compared to co-polar power level. The enhancement of bandwidth, gain and reduction of cross-polar power level does not affect the nature of broadside radiation