Improved Design of the Vivaldi Dielectric Notch Radiator With Etched Slots and a Parasitic Patch

A new design to improve the bandwidth and gain of the dielectric notch radiator is proposed. Rectangular slots are etched on both arms of the antenna to change the current density distribution. More resonant frequencies are created to reduce the voltage standing-wave ratio (VSWR) value and widen the bandwidth. A parasitic rectangular patch is introduced in the endfire aperture to enhance the electric field coupling and to produce stronger radiation in the endfire direction. Both changes improve the low- and high-frequency band performance, respectively. Evolution of the feeding structures is described in detail. Uniform-impedance microstrip line and slotline on the ground are designed to simplify the impedance matching and reduce optimized parameters. The proposed antenna prototype is fabricated and tested with the size of 31.5 mm × 41 mm × 0.508 mm. The measured results show that the bandwidth is 6.75-16.15 GHz under VSWR ≤2, and the corresponding realized gain ranges from 3.52 to 9.44 dBi. The measured radiation patterns are in good agreement with the simulated ones, which validates the design concept.