Abstract
The dumbbell-shaped longitudinal slot antennas are employed as a replacement for the round-ended longitudinal slot antennas. Each dumbbell-shaped slot is excited by an iris and a septum that have offsets from the waveguide centerlines. All the slots are also cut along the waveguide centerlines. It is demonstrated that the resonant length of the proposed dumbbell-shaped slot antennas is much smaller than the round-ended longitudinal slot antennas. Hence, the end-to-end spacings between the adjacent radiating slots as well as the end-to-end spacings between the coupling and the radiating slots increased noticeably in comparison with the arrays consist of the round-ended longitudinal slot antennas. This fact indicates that one can neglect the mutual coupling between the neighboring slots that are associated with the exciting higher-order modes at the slot positions. To better demonstrate the effectiveness of the proposed dumbbell-shaped slot antennas, a planar array antenna consists of the proposed dumbbell-shaped slot antennas have been designed, implemented, and tested. The measurement and the simulation results confirm the effectiveness of the proposed slot antennas.
