New size reduction for patch antenna by parasitic shorting elements

This paper presents a new size reduction technique for a microstrip antenna by adding parasitic L-shaped shorting strips which are equivalent to provide capacitive and inductive loading effects to the patch. With the use of these parasitic elements, the antenna finds an obvious size reduction while maintaining a good broadside radiation characteristic. Because of this attractive radiation feature, the antenna is suitable for circularly polarized (CP) antennas. A new small CP patch antenna operating at 2.492 GHz is therefore proposed using a microwave substrate of dielectric constant, ¿_r=10, with a coaxial probe feed. The total area of reduction is about 82% in comparison with the conventional half-wave patch antenna.