Design of dual-band millimeter-wave multibeam array antenna based on Rotman lens

To address the application requirements of mobile communication systems for airline operational control and in-flight passenger connectivity, a dual-band millimeter-wave multibeam array antenna based on a Rotman lens is proposed. This multibeam array antenna primarily comprises a broadband millimeter-wave Rotman lens and a dual-band substrate integrated waveguide (SIW) slot array antenna. The broadband Rotman lens is realized using a non-dispersive true-time-delay structure based on substrate integrated coaxial line (SICL). The dual-band characteristics of the array antenna are achieved by cascading two SIW slot linear arrays with distinct structural parameters. A broadband SICL-to-SIW transition structure is designed to enable direct integration between the Rotman lens and the SIW slot array antenna, forming the multibeam array antenna. Simulation results demonstrate that the Rotman lens operates over a broadband frequency range of 25-40 GHz, while the SIW slot array antenna functions in dual bands of 26.2-27.8 GHz and 37.3-39.3 GHz. The integrated multibeam array antenna achieves beam scanning within ±30° in both frequency bands. Featuring a simple structure, easy integration, low profile, and dual-band beam-scanning capability, this multibeam array antenna is suitable for 5G mobile communication systems.