Novel 77 GHz SIW Antenna Solution Based on Stacked Waveguide Network for Automotive Radar System

This paper proposes a 77 GHz multi-layer leaky-wave antenna based on a novel transition using a stacked waveguides network (SWN). The antenna consists of three main parts: a feeding part, a stacked waveguides system and a radiating part, which can be designed and optimized independently. The SWN is implemented using Substrate-Integrated Waveguide (SIW) technology, where electromagnetic energy is transferred from lower to upper substrates through etched slots. Thanks to a leaky-wave array (LWA), it's possible to incorporate active electronic components to achieve beam steering. We present the simulation results of the all structure including the E-band WR-12 adapter. The simulated side lobe level (SLL) is below - 20 dB at the operating frequency <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f_{0}=78.5 \mathbf{~ G H z}$</tex>, the simulated reflection is below - 10 dB across the radar frequency band of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$76-81 \text{GHz}$</tex> and the total efficiency is close to 40%.