Fatemeh Norouzian

Signal reduction due to radome contamination in low-THz automotive radar

This paper investigates signal reduction due to contamination of low-THz radar radomes for outdoor applications. A measurement methodology is proposed to characterise the effect of different obscurants on electromagnetic wave propagation. This is achieved by measuring the ratio of two signals: one reflected from the reference target through the contaminated radome and another through the radome without the contaminant. The presence of water content in propagation media is the main cause of performance deterioration of sensors in rainy, snowy and foggy weather. Therefore, the reflectivity and transmissivity of water films on the radome has been measured and analysed at 150 and 300 GHz and measurement results are presented. The measured results are compared to a theoretical model and good agreement has been established. The results show strong correlation between signal reduction and uniform layer of water thickness.

Comparison of pedestrian reflectivities at 24 and 300 GHz

The Radar Cross Section (RCS) is used to characterize the reflectivity of a target, which is essential for the detection performances of an automotive sensor system. Results of RCS measurements of a child mannequin at 300 GHz are presented for the first time and compared with measurements at the current automotive frequency standards (24 GHz). The RCS range and angular profile measurements of the mannequin are obtained in a controlled environment with the aid of a computer controlled turntable. The potential of low-TeraHertz (low-THz) sensors to measure additional characteristic features of pedestrians and hence enhance pedestrian recognition is also shown.

Characterisation of attenuation by sand in low-THz band

Research to quantify the attenuation of 150 GHz and 300 GHz EM waves in sand has been conducted and the results are presented in this paper to investigate the performance of low-THz sensing for outdoor applications when an antenna radome might be contaminated by sand, which is one of the most common types of contaminant in outdoor environments. The signal power deviation has been studied as a function of sand thickness and granule size. Five kinds of granule-size-calibrated silica sands and natural sand were used in the experiment. While the results confirms expected greater attenuation at 300 GHz than that at 150 GHz, it has also been shown that sand composed of coarser particles provide greater attenuation than that of finer particles, which challenges some previously reported results.