Frequency Sensitivity of a Substrate-Integrated WaveguideDevices by FiniteElement Method

Nowadays, many researches have been done to improve microwave devices operation. One of the newest and useful structures in microwave science is Substrate Integrated Waveguide (SIW) which has wide application in active and passive microwave circuits. This paper represented numerical calculation of frequency sensitivity of a SIW device using finite element.The finite element method (FEM) has been shown to be an efficient and flexible way for computing the equivalent circuit parameters of N-port planar devices (microstrip, stripline, rectangular waveguide, etc.).In this paper, the equivalent circuit parameters of the SIW line is calculated utilizing triangular FEM. Determining frequency sensitivity can be helpful in broadband calculation of circuit parameters. Since, in each simulation beside the circuit parameters their sensitivity relative to frequency is calculated. Therefore, the frequency sensitivity of the equivalent circuit parameters is alsodetermined.Good agreement is obtained with results of commercial software.