Full Lumped Element-Based Equivalent Circuit Model for Connected Slot Antenna Arrays

Abstract

A full lumped element-based equivalent circuit model for connected slot antenna arrays (CSAA) is proposed with three configurations of the CSAA being considered: infinite, semi-infinite, and finite slots. First, an equivalent circuit model was developed from the available Green’s Function (GF) based analytical expression of the active impedance of CSAA. It was demonstrated that by combining PI or T networks with parallel RLC resonant circuits and modeling the higher order modes via the series inductor, the active impedance and the reflection characteristics of the CSAA can be represented in an efficient and accurate manner. Secondly, utilizing the proposed equivalent circuit model, a generalized design procedure was developed to assist the design and analysis of arbitrary configurations of CSAA at both microwave and millimeter wave (mm-wave) bands. Finally, the effectiveness and accuracy of the proposed approach are validated by several numerical and measured results. A 2x2 CSAA prototype was fabricated at 3 GHz to validate the proposed equivalent circuit model. For the finite slot case, the proposed RLC+T network outperforms both the available transmission line-based equivalent circuit model and the proposed RLC+PI network, in describing the resonance frequencies and the values of the impedances of the finite slot. It was demonstrated that the proposed equivalent circuit model had a maximum of 4.55% and 5.27% average errors for the real and imaginary parts of the impedances, as compared with the full-wave simulator, while the computational time was reduced by more than two orders of magnitude.