Optimization of Vivaldi antenna for microwave imaging applications

Microwave imaging of dielectric media plays a major role in non-destructive testing, remote sensing, medical imaging etc. The procedure usually requires the measurement of reflection coefficient data of the object under test in free space over a wide frequency band which demands an ultra-wide band antenna. The design of a UWB antipodal Vivaldi antenna through optimization working in a frequency band of 1-18 GHz is discussed in this paper. The design and optimization process is carried out using the full wave EM simulation software, the CST microwave studio and various parameters such as return loss, radiation pattern, directivity and input impedance are computed. The simulated design is validated by fabricating a number of antennas on FR-4 substrate and measuring their return loss as well as radiation characteristics.