Dual-Band and Polarization-Flexible Cavity Antenna Based on Substrate Integrated Waveguide

In this letter, a novel dual-band and polarization-flexible substrate integrated waveguide (SIW) cavity antenna is proposed. The SIW cavity used for the antenna is excited by a conventional
${\rm TE}_{120}$
mode for its first resonance. With the intervention of the slot, a second resonance excited by a modified-
${\rm TE}_{120}$
mode is also generated, thereby providing a broadside radiation pattern at two resonant frequencies. In addition, the proposed antenna has two orthogonal feeding lines. Therefore, it is possible to provide any six major polarization states. In this letter, three major polarization cases are simulated and compared to measured results. Since modern communication systems require multifunctional antennas, the proposed antenna concept is a promising candidate.