Abstract
This paper presents the design of an ultra-wideband (UWB) antipodal Vivaldi antenna (APVA) for radar and microwave imaging applications. A slotted APVA design is introduced to improve the low-end bandwidth limitation frequencies as well as to enhance the gain and directivity of the antenna. The optimizations of the design offer good results by using a cost-effective substrate, fiberglass reinforced grade 4 (FR4) material. The regular APVA antenna design only presents average results of gain (4-6 dBi) and directivity (4-7 dB). However, the addition of slots on the edges of antenna is able to increase the peak value of gain and directivity up to 73.65% with 7.64 dBi and 8.92 dB, respectively. Besides, the radiation pattern of the antenna is also improved by using the slotted design where the main lobe level is larger than regular APVA design. Both antennas presented in this paper are designed in compact size of 42.8 mm x 57.3 mm. The antennas are also designed to operate within the frequency range of 3.6 GHz to 10 GHz frequency.