LAUSR

ABSTRACT Reconfigurable coaxially fed designs of unequal length U-slot cut square microstrip antenna are presented. Reconfigurable approach realizes the connection of shorting posts on the patch edges through the RF PIN diodes that realize either tuning in the center frequency of axial ratio bandwidth or switching between the circular polarized to linear polarized wideband characteristics. On substrate thickness of 0.054λcAR, circular polarized design yields tuning in the center frequency of axial ratio bandwidth by 31.3%, whereas reconfigurable wideband design yields switching between the circular polarized and wideband linear polarized responses. To reduce the substrate thickness, reconfigurable design employing shorted microstrip line feed is proposed. On substrate thickness of 0.037λcAR, reconfigurable design yields axial ratio bandwidth of 12 MHz (1.5%), offering peak antenna gain of above 6 dBi. Against the coaxially fed design, ~0.02λcAR reduction in the total substrate thickness is achieved. The corresponding wideband design yields reflection coefficient bandwidth of 140 MHz (16.47%). With the obtained antenna characteristics, proposed reconfigurable designs can find applications in GPS, Galileo, and LTE band applications. Measurements have been carried out to validate the simulated results that show close agreement.