Long-Range VNA-Based Channel Sounder: Design and Measurement Validation at mmWave and sub-THz frequency bands

With the increasing demand for high bandwidth
wireless communication systems, and with a congested spectrum
in the sub-6 GHz frequency bands, researchers have been looking
into exploration of millimeter wave (mmWave) and sub-terahertz
(sub-THz) frequency bands. Channel modeling is essential for
system design and performance evaluation of new wireless
communication systems. Accurate channel modeling relies on
reliable measured channel data, which is collected by high-fidelity
channel sounders. Furthermore, it is of importance to understand
to which extent channel parameters are frequency dependent in
typical deployment scenario (including both indoor short-range
and outdoor long-range scenarios). To achieve this purpose, this
paper presents a state-of-art long-range 28 GHz and 300 GHz
VNA-based channel sounder using optical cable solutions, which
can support a measurement range up to 300 m and 600 m in
principle, respectively. The design, development and validation of
the long-range channel sounders at mmWave and sub-THz bands
are reported, with a focus on their system principle, link budget,
and back-to-back measurements. Furthermore, a measurement
campaign in an indoor corridor is performed using the developed
300 GHz system and 28 GHz channel sounding systems. Both
measured channels at the 28 GHz and 300 GHz channels are
shown to be highly sparse and specular. A higher number of
Multi Path Components (MPC) are observed for the 28 GHz
system, while the same main MPC are observed for both systems.