Modeling and design of parallel-fed continuous transverse stub (CTS) arrays

This work presents a rigorous and efficient framework for the analysis of continuous transverse stub (CTS) arrays, based on a mode-matching technique. The model focuses on an infinite array of long slots fed in parallel by parallel plate waveguides (PPWs). Closed-form expressions are provided for the active impedance of the array. The accuracy and the simplicity of the model are due to an effective decomposition of the equivalent currents over the slots in PPW modes. An excellent agreement with full-wave simulations is achieved. The developed fast code has been used for the design of a flat, broadband 16-elements CTS array in Ka-band. The main beam can be steered mechanically in H-plane. The scanning capabilities are experimentally demonstrated for several beam pointing directions, up to 27°, and are in very good agreement with simulations. The -3 dB beamwidth in H-plane is 6° at 30 GHz. The radiated performance are stable in the 27.5-31 GHz band. Simulated peak gain values are > 28 dBi, within the targeted scanning range and frequency band.