Study of Resonant Modes in Rectangular Dielectric Resonator Antenna Based on Radar Cross Section

The resonant modes of the rectangular dielectric resonator antenna (DRA) are systematically investigated. Their resonance frequencies are accurately determined by exploring the radar cross section (RCS) characteristic of a DRA in free space. Also, the internal electric and magnetic fields of the first few resonant modes are examined and the mode classification of the rectangular DRA is discussed. It is found that when the length (a) and width (b) of a rectangular DRA are unequal (i.e., a ≠ b), the modes can be generally divided into TE and HEM modes, with no TM modes. It is also found that quasi-TM modes can exist only when a = b.