Van Der Elst, VictorVictorVan Der ElstWilssens, RubenRubenWilssensJocque, JelleJelleJocqueKapusuz, Kamil YavuzKamil YavuzKapusuzLemey, SamSamLemeyVerhaevert, JoJoVerhaevertRogier, HendrikHendrikRogier2026-09-082026-09-082025979-8-3315-1508-9979-8-3315-1509-62474-1760https://imec-publications.be/handle/20.500.12860/60262This work presents the time-domain analysis of a compact polarization-reconfigurable Ultra-Wideband (UWB) antenna implemented in air-filled substrate-integrated waveguide (AFSIW) technology. This antenna is designed for operation in the IEEE-802.15.4z UWB channel 9 frequency band [7.74-8.24 GHz]. The proposed antenna utilizes a U-shaped slot within a quarter-mode AFSIW topology. Two PIN diodes enable +45° /-45° polarization switching by electrically shorting the slot at well-defined positions. Time-domain measurements demonstrate that the polarization-reconfigurable antenna exhibits negligible pulse distortion and virtually no phase-center variation, as confirmed by key UWB performance metrics: System Fidelity Factor (SFF) and Distance Estimation Error (DEE), particularly under varying orientations. It is demonstrated that a polarization-reconfigurable AFSIW antenna can be realized within a compact footprint of 0.6λ0×0.6λ0, achieving SFF values above 95° and DEE ≤3 cm over a 120° field of view. These characteristics make the antenna particularly well-suited for pulse-based UWB localization and sensing systems. PublishedengProceedings paper10.1109/cama65664.2025.11335325WOS:001796509100176INTEGRATED WAVE-GUIDEIR-UWB LOCALIZATIONARRAY