Optimization Using Backtracking Search Algorithm for the Design of Magnetron Anode Block and Pill-Box RF Window

Abstract

Determining the design variables of the magnetron sub-assemblies using empirical equations is a challenge. In this article, with the help of the popular backtracking search algorithm (BSA), the bare anode block of the magnetron and pill-box RF window are designed at frequency of 2.998 GHz. The convergence results with BSA are validated with the harmony search algorithm (HSA) and particle swarm optimization (PSO). The optimized design variables of bare anode are hole radius ( $a$ ), slot length ( $l_{s}$ ), slot width ( $W_{s}$ ), and anode height ( $h_{a}$ ) which are found to be 3.1, 2.9, 12.8, and 100 mm, respectively, and converge within 150 iterations with BSA. The optimized results are compared to simulated results which are nearly identical with a negligible relative difference of $\pi$ -mode is 1.08%. From the pill-box RF window design, multi-objective optimization is carried out to reach the desired frequency and to achieve minimized reflections by maximizing the bandwidth. The corresponding design variables dielectric thickness ( $t_{w}$ ), cavity length ( $C_{l}$ ), and cavity radius ( $C_{r}$ ) which are 2.5, 30.4, and 41.5 mm, respectively. Pareto multi-objective BSA (PMBSA) is validated with the weighted sum approach (WSA). Due to its simplicity and lower latency, optimization approach is helpful to designers to develop the microwave devices.