Abstract-Design and Characterization of CMOS Transmission Lines in Sub-THz Region

Xiuping Li, Weiwei Feng, Hua Zhu

http://www.tandfonline.com/doi/abs/10.1080/02726343.2017.1330603?journalCode=uemg20

Microstrip line, coplanar waveguide, ground coplanar waveguide, and two kinds of slow-wave transmission lines (T-Line) are designed and realized based on a 0.13 μm Complementary Metal-Oxide-Semiconductor (CMOS) process. The radiation loss in the sub-THz region is evaluated by E-field distribution and attenuation coefficient versus the dimensions. Characterizations of these T-Lines up to sub-THz region is performed by sub artificial neural network (ANN) based on T-Line models and measurement results. The sub ANN-based model is capable of capturing the frequency-dependent effect of the resistance, inductance, conductance, and capacitance (RLGC) model up to sub-THz region, promising a compact and wideband modeling approach. The effect of dummy-filling on degrade of T-Lines performance in sub-THz region is also analyzed and evaluated by measurement and simulation results. Good agreement is obtained between the simulation, modeling, and measurement results.

Abstract-Double-stacked hyperbolic metamaterial waveguide arrays for efficient and broadband terahertz quarter-wave plates

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• Xianmin Ke, 
• Hua Zhu, 
• Junhao Li, 
• Lin Chen & 
• Xun Li

http://www.nature.com/articles/s41598-017-00726-3

We demonstrate how it is possible to achieve weak dispersion in the phase delay between two orthogonal polarization states by using double-stacked hyperbolic metamaterial (HMM) waveguide arrays. The weak dispersion in the phase delay originates from the different signs of phase delay from the two different HMM waveguide arrays. The condition of dispersion-free phase delay for the transmitted waves has been theoretically derived from the transmission matrix as the propagation characteristic of the HMM waveguide is involved. We further reveal that the designed double-stacked HMM waveguide array can function as an efficient quarter-wave plate that enables the conversion of linearly polarized light to circularly polarized light within a broad frequency band. In addition, the bandwidth over which the degree of linear polarization is nearly unity and over which the angle of linear polarization is kept at approximately 45° is basically consistent with the phase bandwidth. This offers a promising approach for developing a practical polarization converter in the terahertz domain.