Modified C-shape microstrip antenna for dual and broadband response

Fundamental and higher order modes of C-shape patch are discussed and their comparison against the resonant modes of equivalent rectangular patch is presented. Resonant length formulation for C-shape patch at its higher order mode is proposed. The frequency calculated using the same closely agrees with the simulated frequency. A new configuration of C-shape microstrip antenna loaded with step width open circuit stub is proposed for broadband and multi-band response with dual polarization. The addition of open circuit stub modifies the resonance frequency of second order C-shape patch mode which together with fundamental patch mode yields bandwidth of around 32 MHz (~4%) on thinner substrate. The stub modifies the surface current distribution at second order mode that gives broadside radiation pattern over the bandwidth. With respect to next higher order C-shape patch modes, stub loaded patch yields dual polarized multi-band frequency response with broadside radiation pattern at each of the frequencies. Bandwidth of nearly 2% is obtained at each of the multi-band frequencies.