  The much higher frequencies in the Terahertz (THz) band prevent the effective
utilization of channel models dedicated for microwave or millimeter-wave
frequency bands. In this paper, a measurement campaign is conducted in an
indoor corridor scenario at 306-321 GHz with a frequency-domain Vector Network
Analyzer (VNA)-based sounder. To realize high-resolution multipath component
(MPC) extraction for the direction-scan measurement campaigns in the THz band,
a novel modified space-alternating generalized expectation-maximization (SAGE)
algorithm is further proposed. Moreover, critical channel characteristics,
including the path loss, shadow fading, K-factor, delay spread, angular
spreads, cluster parameters, and cross correlations are calculated and analyzed
in the LoS case. Besides, two contrasted measurement campaigns in the NLoS case
are conducted, with and without additional reflective foils on walls to serve
as effective scatterers. Comparison results indicate that the reflective foils
are useful to improve the channel conditions in the NLoS case by nearly 6 dB,
which is potential to be utilized as alternative of intelligent reflecting
surfaces (IRS) to enhance the coverage ability of THz communications.
