  In the super-heterodyne terahertz communication system, the proper design of
the critical components like mixers and filters are of great importance for
enhancing its performance. In this work, some issues on our newly developed
system setup design for 0.14 THz wireless communications and the key components
subharmonic mixer (SHM) based on Schottky diode, as well as silicon
micromachined bandpass rectangular waveguide filters are presented. According
to ADS simulation, the optimum conversion loss of the 140 GHz SHM is around 8.2
dB. And the silicon-micromachined rectangular waveguide filters have been
fabricated and the measured lowset insertion losses are lower than 0.5 dB.
