A Mobile, High Temporal and Spatial Resolution FMCW Channel Sounder

Previous studies on RF forest propagation have in-vestigated path losses and channel impulse responses as functions of range and foliage type [1]–[2]. Forests are known to be a complex channel that impact the integrity of a signal via phenomena such as fading, dispersion, and spectral broadening. These adverse effects depend on the random distribution of tree trunks, the overall density of the forest, ground reflections, and Doppler shifts resulting from swaying trees. However, these studies have traditionally used insufficient bandwidth to resolve the rich multipath characteristics of through-forest channels. Therefore, we have developed a wide band (160 MHz) frequency modulated, continuous wave mobile channel sounder capable of resolving meter-level detail of forested paths in the L-, S-, and C-Band frequencies. This paper describes the design and testing of this system, as well as presents data from a preliminary forest channel sounding.