volume | PIER Journals

Abstract

High frequency communication systems are critical for 5G networks, particularly in the millimeter-wave bands, where ultra-wideband (5G-UWB) performance is essential for high data rates and low latency. In this work, we propose, for the first time to the best of our knowledge, an ultra-wideband 5G MIMO beamforming module covering both the 28 and 60 GHz bands. The proposed design is based on a low-cost, low-profile Rotman Lens (RL) implemented on an FR4 substrate with a thickness of 1.6 mm and a dielectric constant of 4.3. The RL features five beam ports and seven array ports, with additional dummy ports introduced to minimize reflections and enhance adjacent beam port isolation across the full 5G-UWB range. Simulation results demonstrate excellent performance, with isolation and mutual coupling maintained below -25 dB between input beam ports and below -15 dB between array ports across the entire bandwidth. The VSWR remains below 2 for all ports. Although this work presents a single RL-based beamformer, it is envisioned as a building block within a larger hybrid MIMO architecture, where multiple lenses can be interconnected to support parallel data streams and spatial multiplexing. This modular approach enables flexible scaling to full MIMO operation while maintaining low cost and compactness. The proposed design is a strong candidate for 5G and mmWave applications, including hybrid beamforming systems, MIMO architectures, radar, and satellite communications. Comparative analysis with recent literature demonstrates its superior bandwidth and isolation performance.

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Dr. Noureddine Boughaba

Dr. Ouarda Barkat

Dr. Khaled Issa