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A wideband, wide angle metamaterial Hilbert curve array terahertz absorbing screen is reported. The absorber consists of array of an Aluminum first order Hilbert curve array over a copper ground plane separated by dielectric spacer. 100% fractional bandwidth (-3dB absorption bandwidth) for normal incidence and more than 90% in case of oblique incidence of 45° and 60° for both TE and TM polarizations have been verified numerically. The operating bandwidth of the structure proposed here is several times of those reported to date. Peak absorption is 98% for normal incidence and more than 86% for 60° angle of incidence for either polarization. Furthermore, effects of variations in Hilbert curve dimensions, spacer thickness, spacer permittivity and ground plane conductivity are also investigated. The structure is shown to have high tolerance to variations in the aforementioned parameters. [ABSTRACT FROM AUTHOR]

In this paper, a novel compact and tunable impedance transmission line transformer is presented for the first time. The transformer is designed using a left handed coplanar waveguide transmission line on a ferrite substrate. Based on the dispersive properties of the ferrite medium, the theoretical study of the transformer has been carried out using its equivalent circuit analysis and the composite right / left handed transmission line theory. The theoretical study was verified through full wave electromagnetic numerical simulations. The results show that the transformer matches a 25 Ω load to a 50 Ω line with tunability from 2.55 GHz to 3.2 GHz. The return loss at center frequency is better than 20 dB with insertion loss better than -1 dB. The transformer has a very compact size with dimensions of 4.25 × 21 mm, showing approximately 64% reduction in size in comparison with a conventional right-handed transformer within the same operating frequency band. Moreover, the proposed coplanar waveguide transformer configuration has smaller demagnetization factor and hence it requires smaller DC magnetic bias values compared to microstrip configuration. [ABSTRACT FROM AUTHOR]