Application of PSO algorithm for optimizing the dimensions of tunable interdigitated capacitor

Abstract

In this paper, we describe an approach to optimize the dimensions of a tunable interdigitated capacitor using particle swarm optimization (PSO) algorithm. Analytical model of an interdigitated capacitor (IDC) is developed using conformal mapping method (CMM) and partial capacitance technique (PCT). The dimensions of IDC operating at 1 GHz frequency with capacitance values of 1 pF to 5 pF are extracted using PSO algorithm. The structural dimensions of tunable IDCs are simulated using finite difference time domain (FDTD) based software (IMST's Empire). The designed IDC shows approximately 20% tunability with 30% variation in dielectric constant of the tunable BST (Barium Strontium Titanate (Ba 0.5Sr 0.5TiO 3)) thin film on which the modeled IDC structure is patterned. The obtained results from numerical simulation shows that PSO algorithm is able to calculate the dimensions of tunable IDCs accurately and successfully and this technique can be applied to extract the dimensions of any planar microwave device.