A Waveguide Based Terahertz Variable Attenuator

A variable attenuator is a critical component at microwave and terahertz frequencies to adjust the signal path loss-gain settings in the system. This facilitates designers and engineers to determine the optimum performance of their measurement systems and instruments. Attenuators, both fixed and tunable, are readily available at microwave frequencies however at submillimeter-wave and terahertz frequencies, design and fabrication are very challenging because such components need to be integrated with compact metal waveguide packaged sub-systems and instruments. In this work, we demonstrate a novel waveguide based variable attenuator at WR1.5 band (500-750 GHz) using a metal coated silicon slab. A piezo electric motor is used to control the position of the slab on the path of the incoming electromagnetic signal to achieve variable attenuation. The amount of attenuation is determined by the volume of silicon slab inside the waveguide and the absorption coefficient of the metal coating.