A novel broadband coaxial probe to parallel plate dielectric waveguide transition at THz frequency

In this paper, transmission characteristics of the fundamental mode (TE(10(12))) of Parallel-Plate Dielectric Waveguide (PPDW) at 0.4-1.0 THz (1 THz = 10(12) Hz) are studied. The investigation results show PPDW with virtually low attenuation and remarkable simple structure is a promising candidate as THz transmission medium. Then, a novel broadband coaxial probe to PPDW transition is designed. Although coaxial probe excitation has been used in microstrip lines and rectangular waveguides in microwave, millimeter-wave frequency domain, the present study shows that it is also an effective method to excite the PPDW at THz frequency. As the investigation results show, the return loss of coax-PPDW transition is better than 20 dB from 0.45 THz to 0.75 THz, and the insertion loss is as low as 0.18 dB, which will have wide potential application in the terahertz regime.