Folded Rotman lens multibeam antenna in SIW technology at 24 GHz

We introduce here a new dual-layer multibeam antenna with a folded Rotman lens used as a compact beam forming network in SIW technology. The objective is to reduce the overall size of the antenna system by folding the Rotman lens on two layers along the array port contour and using a transition based on an exotic reflector and several coupling vias holes. To validate the proposed concepts, an antenna system has been designed at 24.15 GHz. The radiating structure is a SIW slotted waveguide array made of fifteen resonant waveguides. The simulated results show very good scanning performances over ±47°. It is also demonstrated that the proposed transition can lead to a size reduction of about 50% for the lens, and more than 33% for the overall size of the antenna.