New Technique to Excite Higher-Order Radiating Mode in a Cylindrical Dielectric Resonator Antenna

Higher-order HEM_12δ mode has been experimentally realized in a cylindrical dielectric resonator antenna (CDRA) very recently revealing broadside radiation like the dominant HEM_11δ mode. The primary challenge is the excitation of the mode in a practical DRA sitting on a metal ground plane, which was first resolved by introducing a floating feed as an equivalent current ribbon. In this letter, yet another technique has been explored using a conventional probe-fed CDRA placed on a metal plate. Only a new trough-shaped air cavity has been introduced in the ground plane just beneath the DRA to simulate a special boundary condition, which enunciates desired modal fields. Such a technique may be improvised for other potential applications. The proposed concept has been verified using both simulated and experimental results.