Transmission characteristics of lens-duct, Cytop planar photonic crystal waveguide (PPCW) and hollow-core microstructured optical fiber were analyzed in the terahertz (THz) region. The lens duct was able to channel and couple the THz radiation into a Teflon waveguide with a loss of about $0.7\mathrm{dB}$ . Single-mode propagation and frequency-selective properties were achieved using PPCW whose central frequency is at $0.45\mathrm{THz}$ . Results of time-domain spectra of the hollow-core microstructured polymer optical fiber showed a difference of about $20\mathrm{ps}$ between the THz waves that propagated in the core and cladding. Frequency shift of the transmission bands between waveguides of different size suggested photonic bandgap guidance. Finite-difference time domain calculations agreed relatively well to the experimental results of PPCW and hollow-core fibers.