Designing high-performance finline tapers with vector-based optimization

In this paper, a novel two-step optimization algorithm is presented for the design of high-performance finline tapers. The first step utilizes a focusing approach, where the optimization is performed with an increasing number of variables, while the second step exploits the vector representation of the integral form of the reflection coefficient of smoothly varying tapers. A few high-performance X-band tapers are designed and measured, including one measuring only 0.47/spl lambda//sub 0/ (17.5 mm) at 8 GHz with a 25-dB reflection bandwidth of 7.4-11.3 GHz, and one designed to work without a quarter-wave notch transformer, with a 30-dB reflection bandwidth of 8.1-10.9 GHz.