  In the evolving landscape of terahertz communication, the behavior of
channels within indoor environments, particularly through glass doors, has
garnered significant attention. This paper comprehensively investigates
terahertz channel performance under such conditions, employing a measurement
setup operational between 113 and 170 GHz. Analyzing scenarios frequently
induced by human activity and environmental factors, like door movements, we
established a comprehensive theoretical model. This model seamlessly integrates
transmission, reflection, absorption, and diffraction mechanisms, leveraging
the Fresnel formula, multi-layer transmission paradigm, and knife-edge
diffraction theory. Our experimental results and theoretical predictions
harmoniously align, revealing intricate dependencies, such as increased power
loss at higher frequencies and larger incident angles. Furthermore, door
interactions, whether opening or oscillations, significantly impact the
terahertz channel. Notably, door edges lead to a power blockage surpassing the
transmission loss of the glass itself but remaining inferior to metallic handle
interferences. This paper's insights are pivotal for the design and fabrication
of terahertz communication systems within indoor settings, pushing the
boundaries of efficient and reliable communication.
