Terahertz free‐space dielectric property measurements using time‐ and frequency‐domain setups

Abstract

Based on a simple and effective calculation method, two free‐space measurement setups are employed to investigate the dielectric properties of various materials at terahertz (THz) frequencies. One setup involves THZ time‐domain spectroscopy (THz‐TDS) at a frequency range of 0.4 to 1 THz. The other setup comprises a vector network analyzer (VNA) with pairs of VAN extenders (VNAXs) and diagonal standard gain horns (SGHs) at a frequency range of 0.22 to 1.1 THz. The calculation method is verified for the THz‐TDS system and employed in the VNA system for the first time. Dielectric properties, including refractive indices, power absorption coefficients, relative permittivities, and loss tangents, are calculated from measured transmission data. Several materials, including printed circuit boards and 3D printing materials, are characterized to verify the calculation method and compare the measurement setups.

Microwave and terahertz properties of porous Ba4(Sm,Nd,Bi)28/3Ti18O54 ceramics obtained by sacrificial template method

“…The coefficient of determination (r 2 ) of the fitting in Figure 10 is 0.90, indicating that the relationship between total porosity and r in the terahertz region is in good agreement with the linear approximation of the Bruggeman theory, similar to that in the microwave region. However, a small deviation from the ideal linearity and r scattering around the fitting curve can be observed, which may result from the less accurate value of r obtained from the terahertz time-domain technique, 25 as compared to the Hakki-Coleman 21 post-resonator method in the microwave region.…”

“…The terahertz time-domain spectra were measured using a terahertz time-domain spectrometer system (Z3; Zomega Terahertz Corp.) in transmission mode in a highpurity nitrogen environment. The optical and dielectric properties of the BSNBT ceramic samples in terahertz frequency range were extracted from the spectra using fast Fourier transform (FFT), and the following equations 24,25 :…”

Orbital Angular Momentum (OAM) Mode-Reconfigurable Discrete Dielectric Lens Operating at 300 GHz

“…f f r j j f r j j spectroscopy and vector network analyzer (VNA) frequency-domain setups in [43]- [44]. High temperature resin is chosen as the printing material in this design for its high resistance to scratching and deformation.…”

Symmetric coplanar waveguide sensor loaded with interdigital capacitor for permittivity characterization

“…Microwave sensor can be used for determining the dielectric characterization of materials, and this characteristic makes it very useful in agricultural, industrial, scientific, and biomedical applications . According to the Debye theory, the dielectric parameter of material is dependent on the working frequency .…”