V-band SIW Slot Antenna Integration - Automotive In-Cabin Radar

In collaboration with a leading automotive OEM, Raytech developed a V-band substrate integrated waveguide (SIW) slot antenna to improve in-cabin radar performance. The radar system integrates FR4-based SIW slot antennas for 3 receivers and 2 transmitters directly onto the main board, enabling a compact, low-cost 3Rx/2Tx array covering the full V-band application range (57–64 GHz).

Radiation Pattern & Gain Test Setup - Rx Antenna

Fabricated Rx antenna prototype connectorized with a 1.85 mm interface at the input section, mounted in an anechoic chamber for radiation pattern and gain measurement. This setup validates the antenna's far-field performance against simulation prior to full radar system integration

SIW Characterization via Comparison to Microstrip Line

Measured insertion loss (S12, right axis) and return loss (S11, left axis) characterizing the SIW structure, benchmarked against a standard 50 Ω microstrip line. The SIW insertion loss (yellow) is measured in a back-to-back configuration, so the effective per-transition loss is roughly half the plotted value — outperforming the microstrip line insertion loss (red). The SIW also demonstrates excellent return loss performance across the full 56–64 GHz band, confirming low-loss, well-matched signal transitions suitable for V-band integration. Both structures are the same length, showing that the microstrip-to-SIW conversion introduces no noticeable additional loss compared to the microstrip line alone.

(Top) Microstrip line insertion loss test setup. (Bottom) SIW back-to-back insertion loss test setup. This test was performed using Rogers Duroid 5880 substrate; additional data using FR4-based substrate is available upon request.