Multi-band Configurations of L-shape and F-shape Microstrip Antennas

Abstract

Compact L-shape microstrip antenna is proposed. With respect to first three resonant modes, L-shape patch gives multi-band frequency response with broadside radiation pattern. To realize tunable frequency ratio with respect to three resonant modes, L-shape patch is loaded with open circuit stub which yields novel F-shape microstrip antenna. The variation in stub length yields tuning of first three resonant mode frequencies and gives bore-sight radiation pattern at each modes. With reference to first two resonant modes, for smaller stub length, F-shape patch gives dual band dual polarization response whereas for larger stub length, it yields dual band single polarization response. Thus here stub length variations yields tuning of two polarizations. The L-shape and F-shape microstrip antenna gives 1 to 2% of VSWR bandwidth at each resonant modes in 1000 MHz frequency spectrum.