A SPICE Model of Rectangular Microstrip Antennas for Receiving

This paper presents a SPICE model for calculating the coupling voltages of a rectangular microstrip antenna illuminated by plane waves. A receiving model based on Thévenin´s theorem is first established in which the ideal voltage source is calculated by the reciprocity theory and the impedance is calculated by the cavity model. Then, by using the method of vector fitting, the obtained receiving model is approximated by rational functions, which can be directly converted to RLC circuits. The proposed SPICE model, which allows the incorporation of either time-varying or nonlinear loads, can be applied to both frequency-domain and time-domain analyses. The proposed SPICE model was verified by several numerical examples.