On the improving coupling between coplanar waveguide and low-permittivity dielectric resonator antenna

In this paper, a technique for improving the input matching of a CPW-fed DR antenna with low permittivity by adding a vertical strip extended from the center strip of the CPW on the surface of the DR is proposed. The DR antenna operates at the HEM_11δ broadside mode. The added strip operates like a vertical dipole, which can excite the meridian E-field mode of the DR antenna. The original aperture fed by the CPW acts as a horizontal magnetic current source, which excites the H-field in the equatorial plane. The improved coupling is expected because an additional coupling mechanism is introduced by adding the vertical strip. Moreover, the two forms of coupling by the aperture and the added vertical strip may excite two staggered resonant modes, which may be very close so that wideband operation is formed.