  Due to large reflection and diffraction losses in the THz band, it is
arguable to achieve reliable links in the none-line-of-sight (NLoS) cases.
Intelligent reflecting surfaces, although are expected to solve the blockage
problem and enhance the system connectivity, suffer from fabrication difficulty
and operation complexity. In this work, non-intelligent reflecting surfaces
(NIRS), which are simply made of costless metal foils and have no signal
configuration capability, are adopted to enhance the signal strength and
coverage in the THz band. Channel measurements are conducted in typical indoor
scenarios at 306-321 GHz and 356-371 GHz bands to validate the effectiveness of
the NIRS. Results measured with NIRS in different sizes show that large NIRS
performs much better than small NIRS. Furthermore, by invoking the NIRS, the
additional reflection loss can be reduced by more than 10~dB and the coverage
ratio is increased by up to 39$\%$ for a 10~dB signal-to-noise ratio (SNR)
threshold.
