Compact Rotman lens-fed slot array antenna with low sidelobes

• Published in: IET microwaves, antennas & propagation Vol. 12; no. 5; pp. 656 - 661
• Main Authors: Liu, Yi, Yang, Hu, Jin, Zusheng, Zhao, Fei, Zhu, Jiang
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 18.04.2018
• Subjects: antenna feeds; antenna radiation patterns; array signal processing; azimuthal plane; beam‐forming network; central beam; compact multibeam antenna; compact Rotman lens‐fed slot array antenna; coupling power; double‐stepped coupling slots; edge beams; frequency 10 GHz; frequency response; lens antennas; low‐sidelobe application; measured radiation patterns; microstrip Rotman lens; multibeam antennas; radiating part; rectangular transverse coupling slot; SIW technology; slot antenna arrays; Special Issue: Selected papers from the Loughborough Antennas & Propagation Conference (LAPC 2016); substrate integrated waveguides; substrate‐integrated waveguide technology; beam-forming network; central beam; azimuthal plane; SIW technology; compact Rotman lens-fed slot array antenna; radiating part; microstrip Rotman lens; low-sidelobe application; measured radiation patterns; lens antennas; compact multibeam antenna; substrate-integrated waveguide technology; multibeam antennas; edge beams; rectangular transverse coupling slot; antenna radiation patterns; slot antenna arrays; antenna feeds; double-stepped coupling slots; frequency 10 GHz; frequency response; substrate integrated waveguides; array signal processing; coupling power
• ISSN: 1751-8725; 1751-8733; 1751-8733
• DOI: 10.1049/iet-map.2017.0466

A slot array in substrate-integrated waveguide (SIW) technology fed by a microstrip Rotman lens is proposed. This compact multibeam antenna is designed in two layers using a novel transition based on double-stepped coupling slots on the broad wall of SIWs. Compared with a rectangular transverse coupling slot, this transition is broadband and its coupling power can be controlled for low-sidelobe applications. The radiating part is a 10 × 10 slot array and the beam-forming network can generate seven beams with good coverage from −30° to 30° in the azimuthal plane. To validate the proposed concept, an antenna prototype is implemented at 10 GHz. The frequency response and measured radiation patterns are in good agreement with simulated results provided by full wave simulation software. Experimental results show that the sidelobe level is lower than −21 dB for the central beam in both H and E planes and better than −18 dB for the edge beams.