A novel composite right-/left-handed (CRLH) backward-wave coupled-line directional coupler with arbitrary coupling level and broad bandwidth is presented, explained by even/odd-mode analysis, validated full-wave simulations, demonstrated experiments. First, the CRLH-transmission-line (CRLH TL) theory given, a microstrip implementation of CRLH TL described. simple circuit model then proposed both for understanding design coupler. The exhibits very unusual characteristics, such as zero...

The composite right/left-handed (CRLH) transmission line (TL) is presented as a general TL possessing both left-handed (LH) and right-handed (RH) natures. dispersion diagram of the two-dimensional (2-D) CRLH-TL obtained analytically based on Bloch-Floquet theory, unique phenomenon infinite guided-wavelength propagation, with nonzero group velocity at frequency, explained. It shown that when CRLH "balanced", two eigenfrequencies /spl Gamma/ point (/spl beta/=0) Brillouin zone (BZ) degenerate...

Planar distributed periodic structures of microstrip-line and stripline types, which support left-handed (LH) waves are presented their negative refractive index (NRI) properties shown theoretically, numerically, experimentally. The supported LH wave is fully characterized based on the composite right/left-handed transmission-line theory dispersion characteristics, indexes, Bloch impedance derived theoretically. In addition, formulas to extract equivalent-circuit parameters from full-wave...

Water scarcity and climate change pose significant challenges to sustainable agriculture, emphasizing the need for optimized irrigation practices. This study evaluates impact of limited (0.45 L/day per plant) compared a control (0.87 on tomato fruit quality metabolic responses. Limited enhanced flavor by reducing pH from 4.2 3.4 improved cellular integrity, with electrolyte leakage decreasing 50% 26%. Antioxidant levels increased, vitamin C content rising 49 64 mg 100 g−1 FW, while glucose...

Ballistic phonon transport was observed in Si films containing Ge nanodots. In SiGe nanodots, thermal conductivity drastically reduced close to that of amorphous materials due alloy scattering and nanodot scattering.

A via-free microstrip left-handed (LH) transmission line (TL) is proposed, which enables easy and low-cost fabrication of backward wave TLs. Based on the equivalent circuit, dispersion characteristics TL are theoretically obtained effect virtual short capacitance LH bandwidth shown. The balanced/unbalanced CRLH criterion for seamless transition from forward propagation also derived. implemented support confirmed both by full-wave FEM simulations experiments. 38-cell exhibits a to scanning...

Planar distributed full-tensor anisotropic metamaterials for cloaks of invisibility based on transformation electromagnetics are proposed. The proposed composed nonresonant transmission lines and advantageous in full control the off-diagonal components permeability tensor as well broadband low-loss characteristics. explicit design formulas given equivalent circuit derived directly from Maxwell's equations. A carpet cloak is designed validity theory confirmed by simulations. In addition,...

We demonstrate anomalous reflectors at 140 GHz for the application of 6G communication coverage expansion. The are designed on cyclo-olefin polymer (COP) substrates basis measured complex permittivity and conductivity millimeter frequencies obtained with balancedtype circular disk resonator method. From full-wave simulations, we confirm that nearly perfect reflection characteristics realized suppressed parasitic reflections in undesired directions. simulated efficiencies excluding material...

We propose an ultrathin perfect absorber for normal incident waves using a Dirac cone metasurface with the thickness of 1/38 free-space wavelength. First, we prepare metasurfaces consisting periodic metallic chain patterns on dielectric substrate having Γ-point frequencies approximately 30 GHz. The is designed by adjusting external coupling their densities. Based one-port resonator model, clarify that realized at critical condition identical internal and Q-factors. experimentally demonstrate...

Terahertz chiral sensing and polarization-multiplexing communication demand subwavelength devices that dynamically invert polarization helicity. Metasurfaces can enhance anisotropy fine tunability at scales for this purpose. Although metasurfaces enabling deep modulation between orthogonal polarizations have been designed, they suffer from low conversion efficiencies. In study, it is shown the efficiency of linear to circular by conventional single-layer transmissive cannot exceed a...

Abstract We propose reconfigurable anomalous reflectors with stretchable elastic substrates. The proposed reflector dynamically controls the reflection direction by mechanically stretching substrate to induce a physical change of unit cell period. Owing simple and scalable tuning mechanism, approach is applicable in millimeter-wave terahertz bands for wide steering. To demonstrate approach, are designed at 140 GHz normal incident waves. From full-wave simulations, we numerically confirm that...

Artificial dielectrics of very high equivalent permittivity are designed and fabricated by use a patterned PCB printed circuit board. Rectangular metal patterns etched out to attain as big capacitance with each other possible but small current possible, which is important in order realize large loss, respectively. dielectric disk resonators created excite the TE/sub 01/spl delta// mode selectively, aligning rectangular along direction electric field lines. Thus, miniaturized BPF superior...

We propose a new waveguide type traveling-wave microwave power divider that is adequate for high applications. The composed of multiple stages reflectionless dividing units, each having two output ports. Design formulas equal-power are first derived. Structural parameters wideband design two- to six-stage dividers then obtained by means numerical analyses based on an equivalent circuit. Comparison experiments at X-band shows good qualitative agreement with the analyses. Typical measured...

A novel broadband left-handed (LH) coupled-line backward coupler with arbitrary coupling level is presented. This composed of two LH transmission lines (TL) constituted series interdigital capacitors and shunt shorted-stub inductors. quasi-0dB implementation the demonstrated by simulation measurement results, shown to exhibit a bandwidth 35% despite relatively wide lines-gap 0.3mm. An even/odd modes analysis presented explain working principle component. 3dB-quadrature implementation, 37%...

The radio-over-fiber (RoF) technology is effective in millimeter-wave (MMW) wireless systems for future broadband massive mobile communication. In constructing MMW RoF systems, a device converting signals into lightwave important. particular, conversion optical single-sideband (SSB) modulation rather attractive since the signal fading caused by chromatic dispersion effect of an fiber does not occur. We have proposed new SSB modulator using array-antenna-electrode and polarization-reversed...

We propose a waveguide type microwave power divider/combiner of double ladder multiport structure which is advantageous for its very low insertion loss and high capability. Analysis based on equivalent circuits give the design formula perfect dividing/combining. Numerical analysis gives optimal parameters broadband characteristics both divider combiner. Analyses flows in isolation characteristic are given. Operation divider-combiner system effect phase deviation combiner input signals...

Simple and compact multi-stage microwave bandpass filters (BPFs) using /spl lambda//4 stepped-impedance resonators (SIRs) fabricated on coplanar waveguide (CPW) are presented, which applicable for MMICs or high-T/sub c/ superconducting filters. An accurate, tuning-free, design method of the SIR-BPF is demonstrated with assistance full-wave electromagnetic field simulator, based a conventional filter impedance inverters. Full-wave simulation experimental results two-stage Chebyshev BPF...

Abstract In this article, we propose all-dielectric carpet cloaks composed of jungle gym shaped dielectric unit cells and present a design strategy for three-dimensional (3-D) anisotropy control based on the transformation optics. The are 3-D printable operate with polarization independent incident waves in arbitrary angles due to control. Realizable anisotropic permittivities cubic rectangular numerically studied relative permittivity loss tangent ɛ r = 2.9 tan δ 0.02 ultra-violet curing...

We experimentally demonstrate the broadband and highly efficient inversion of rotation direction terahertz circular polarization achieved by a dynamic metasurface with vanadium dioxide (VO2). This converts linear into polarization. The rotational output can be reversed based on VO2 phase transition. state dynamically switched injecting direct current an on-chip circuit. To improve terahertz-wave utilization efficiency, is operated at incident angle 45°, thereby eliminating beam splitter...

A physical equivalent circuit model for 2D full-tensor anisotropic materials is presented. From the analysis, it shown that diagonal components of permeability tensor directly correspond to self inductances per unit length, and off-diagonal physically mutual inductance length. carpet cloak designed its operation confirmed with simulations. The complex voltage distributions agree well those corresponding specular reflection cases, validity usefulness proposed are confirmed.

We demonstrate broadband transmission-line illusions based on transformation electromagnetics at microwave frequencies by using the distributed full-tensor anisotropic medium. Due to an intrinsic nature of non-resonant unit cell medium, operate from DC upper limit frequency where homogeneous medium approximation holds. Two-dimensional groove and bump illusion media mimicking scattered waves original a are designed. Their incident angle independent operations confirmed circuit simulations....

Abstract This paper describes the results of an investigative case study to identify causes productivity decline in oil well and a successful chemical treatment restore productivity. A Japanese field has suffered from significant beginning commercial production. Pressure build up tests have shown presence formation damage becoming larger as production goes. Then we considered possibility asphaltene deposition, which been observed most surface facilities, near wellbore restricting flow...