Design and development of wideband and dual-band microstrip antennas

A study of the wideband and dual-band characteristics of single- and double-notched rectangular patch antennas is presented. A comparative study of the experimental results employing coax, microstrip, aperture-coupled and electromagnetically coupled feed techniques has been made for increased bandwidth and improved crosspolar level. Optimum coax-fed location, input resonant resistance and notch parameters are estimated using the transmission-line model. The experimental radiation patterns were compared with simulated and theoretical patterns and found to be in good agreement. The maximum measured impedance bandwidths of 26.6% in band 1 and 31.7% in band 2 have been achieved for coax-fed single-notched patches. A double-layered double-notched aperture coupled (composite) patch antenna was also designed, and further improvement in impedance bandwidth of 39% was achieved without significant degradation in radiation characteristics. From the measured and calculated results it can be seen that single- or double-notched composite patches can be designed to yield wide- and dual-band operations suitable for mobile communications.