1,720,965 research outputs found
Investigating the Loss Mechanism in Terahertz Spoof Surface Plasmon Polaritons
No full textPhotonic Networks and Devices, Networks 2021 - Part of OSA Advanced Photonics Congress 2021 -- 26 July 2021 through 29 July 2021 -- 174143We present the methodology to estimate the loss/confinement levels of Terahertz Spoof Surface Plasmon Polariton waveguides, for the first-time, using dispersion curve analysis and, verify with experiments. ©2021TheAuthor(s
Design of Spoof Surface Plasmon Polariton Based Terahertz Delay Lines
No full textWe present the analysis and design of fixed physical length, spoof Surface Plasmon Polariton based waveguides with adjustable delay at terahertz frequencies. The adjustable delay is obtained using Corrugated Planar Goubau Lines (CPGL) by changing its corrugation depth without changing the total physical length of the waveguide. Our simulation results show that electrical lengths of 237.9 degrees, 220.6 degrees, and 310.6 degrees can be achieved by physical lengths of 250 mu m and 200 mu m at 0.25, 0.275, and 0.3 THz, respectively, for demonstration purposes. These simulations results are also consistent with our analytical calculations using the physical parameter and material properties. When we combine pairs of same length delay lines as if they are two branches of a terahertz phase shifter, we achieved an error rate of relative phase shift estimation better than 5.8%. To the best of our knowledge, this is the first-time demonstration of adjustable spoof Surface Plasmon Polariton based CPGL delay lines. The idea can be used for obtaining tunable delay lines with fixed lengths and phase shifters for the terahertz band circuitry
Fixed Physical Length Spoof Surface Plasmon Polariton Delay Lines for a 2-Bit Phase Shifter
No full textA novel and promising candidate for the main building block of the 2-bit, 360 degrees phase shifters, namely, the fixed physical length, spoof surface plasmon polariton (sSPP) delay lines, is presented. An analytical approach is used for the calculation of the electrical lengths of the sSPP delay lines for what we believe is the first time. The delay lines use the idea of changing the corrugation depths of the sSPP waveguides (WCs), which allows us to obtain different electrical lengths without changing the physical length of the WG. The special design of the coplanar WG to sSPP WG transitions maintains the mode conversion under different phase states and minimizes the insertion and return losses for all phase states. The measurement results of the fabricated delay lines for four different phase states show good agreement with the simulations, having average and maximum phase errors of 1.7% and 3.6% with respect to the ideal phase states, 0.5% and 1.2% with respect to the simulations, and average and maximum insertion losses of -0.26 and -0.43 dB at 7.15 GHz, respectively. The proposed designs, to the best of our knowledge, are the first instances of the sSPP delay lines for low-loss, high-accuracy, compact phase shifters with real-life design constraints. (C) 2020 Optical Society of Americ
Modelling of the Effective Dielectric Constant of Corrugated Planar Goubau Lines for Terahertz Band
No full textWe present the modelling of effective dielectric constant of Corrugated Planar Goubau Lines (CPGL), which can support spoof Surface Plasmon Polaritons (sSPP) at terahertz band. The model proposes an empirical formulation of the effective dielectric constant as a function of CPGL dimensions, namely corrugation depth, aperture, and periodicity, in combination with the dielectric constant and thickness of the substrate. We then verified the model over a wide range of CPGL corrugation depths using finite element simulations, and we achieved an effective dielectric constant error better than 5% and 7% at 250 and 275 GHz, respectively
Design and Simulation of Spoof Surface Plasmon Polariton Delay Lines at 1 Thz
No full textWe present design and simulation of spoof Surface Plasmon Polariton (sSPP) delay lines with same physical length to compose a 1-bit 180ᵒ phase shifter at 1 THz. The sSPP delay lines are based on single conductor waveguide, which has rectangular and identical corrugations on both sides and is attached to a dielectric. The delay lines are engineered by determining only the corrugation depths and keeping all the other parameters same as each other. The corrugation depths of the delay lines vary between 4.5 μm and 15.75 μm. The average percentage phase error, insertion and return losses of 207 μm delay lines are %2.6, -2.2 dB and -17.54 dB at 1 THz, respectively
Terahertz Spoof Surface Plasmon Polariton Waveguides: a Comprehensive Model With Experimental Verification
No full textSpoof surface plasmon polariton waveguides are perfect candidates to enable novel, miniaturized terahertz integrated systems, which will expedite the next-generation ultra-wideband communications, high-resolution imaging and spectroscopy applications. In this paper, we introduce, for the first time, a model for the effective dielectric constant, which is the most fundamental design parameter, of the terahertz spoof surface plasmon polariton waveguides. To verify the proposed model, we design, fabricate and measure several waveguides with different physical parameters for 0.25 to 0.3THz band. The measurement results show very good agreement with the simulations, having an average and a maximum error of 2.6% and 8.8%, respectively, achieving 10-to-30 times better accuracy than the previous approaches presented in the literature. To the best of our knowledge, this is the first-time investigation of the effective dielectric constant of the tera hertz spoof surface plasmon polariton waveguides, enabling accurate design of any passive component for the terahertz band.Turkish Academy of Sciences (TUBA GEBIP 2015
Spoof Surface Plasmon Polariton Delay Lines for Terahertz Phase Shifters
No full textThe terahertz gap attracted interest of researchers with its captivating properties such as its potential for ultrawideband communication and high-resolution imaging applications, which require robust and efficient terahertz components and circuits. Terahertz spoof surface plasmon polaritons are perfect alternatives to implement terahertz integrated circuits. We present the first-time demonstration of the terahertz spoof surface plasmon polariton delay lines for terahertz phase shifters, which present an unprecedented insertion phase versus loss performance. The electrical lengths of the proposed delay lines are tuned just by changing the corrugation depths, which allows the designer to keep the physical length of the delay lines constant. In order to verify the proposed idea, four different delay lines having the same length of 1052.5 mu m are designed, where the electrical lengths of the delay lines are selected to represent the four different phase states of a 2-bit phase shifter. The measurement results of the fabricated terahertz delay lines show almost perfect phase accuracy and very good agreement with the simulations, having an ultra-low average phase error of 0.6%, and average insertion and return losses of -2.3 and -18 dB, respectively. These measurements result in, to the best of our knowledge, a record-high figure-of-merit of 90 degrees/dB compared to all other kinds of planar waveguides at 0.3 THz. The proposed delay lines emerge as a very high-performance and promising candidate for all the waveguide-based components that are crucial for the terahertz integrated circuits
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Design of Subwavelength Confinement Waveguides at 1 Thz Band
No full textIn this paper, we present the design and simulation results of the Terahertz Subwavelength Confinement Waveguides (TSCW) operating at 1 THz. The design of the TSCWs includes CPW-to-TSCW transition circuits and the Spoof Surface Plasmon Polariton (SSPP)-based waveguides. The best-case simulation results exhibit return loss and insertion loss of -13.86 dB and -1.72 dB for the back-to-back (b-to-b) transition circuit and -26.5 dB and -4.66 dB for the TSCW with a total length of 267 µm at 1 THz, respectively
- …
