Circularly polarized design of resonant V-slot-cut square microstrip antenna

For two bands response with the circular polarization in the first band, a square microstrip antenna imbibed with a V-slot of unequal arm lengths is proposed. The unequal arm lengths of the V-slot enable degeneration of the basic TM₁₀ mode into two perpendicular and diagonally directed resonant modes that achieve circular polarized radiation characteristics in the first band. Further an appropriate interspacing of these degenerated fundamental mode frequencies as per the modified TM₀₂ mode, yields dual band characteristics with linear polarized broadside radiation pattern in the second band. This antenna provides a maximum broadside gain larger than 8 dBi and 21 MHz (2.71%) of axial ratio bandwidth in the first band. Over a second band, the configuration provides broadside characteristics including a highest gain of almost 8.5 dBi. In the two bands antenna gives reflection coefficient bandwidth of 80 MHz (10.12%) and 63 MHz (5.5%), respectively. These features allow the suggested antenna to be used in wireless systems that require frequency agility. The experimental verification of the acquired parameters exhibited good matching with simulated outcomes.