Wave-tilt characteristics of TE-mode waves

1981 ◽  
Vol 18 (2) ◽  
pp. 382-385 ◽  
Author(s):  
Ramesh P. Singh ◽  
Tarkeshwar Lal
Keyword(s):  
Dielectric Constants ◽  
Phase Changes ◽  
Earth Model ◽  
Frequency Range ◽  
Homogeneous Half Space ◽  
Te Mode ◽  
Tm Mode ◽  
Displacement Currents ◽  
Lower Frequency Region ◽  
Wave Tilt

The dependence of TE-mode wave-tilt on frequency and altitude of measurement, and the resistivity and dielectric constants of the ground have been investigated. Computational results showing the influence of these parameters on the amplitude and phase of the wave-tilt over a homogeneous half-space earth model have been presented. In contrast to TM-mode waves, the wave-tilt effects for TE-mode are stronger in the lower frequency region. In the lower frequency range, the amplitude decreases with the increase in resistivity of the ground, whereas it increases for an increase in dielectric constant value. When the displacement currents are ignored, the magnitude of amplitude of wave-tilt is reduced considerably. The altitude of measurement has minimal effect on the amplitude, but the phase changes appreciably in some cases.

Influence of permeability on wave-tilt of EM waves

1982 ◽  
Vol 19 (6) ◽  
pp. 1323-1325 ◽  
Author(s):  
Ramesh P. Singh ◽  
Tarkeshwar Lal
Keyword(s):  
Half Space ◽  
Magnetic Permeability ◽  
Pronounced Effect ◽  
Earth Model ◽  
Theoretical Studies ◽  
Computational Results ◽  
Frequency Range ◽  
Magnetic Wave ◽  
Homogeneous Half Space ◽  
Wave Tilt

Theoretical studies on the influence of magnetic permeability on the amplitude and phase of electric and magnetic wave-tilt have been carried out in the frequency range 102–106 Hz over a homogeneous half-space Earth model. Computational results show a pronounced effect of magnetic permeability on the amplitude of wave-tilt measurements.

scholarly journals A hybrid broadband metalens operating at ultraviolet frequencies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farhan Ali ◽  
Serap Aksu
Keyword(s):  
Dielectric Material ◽  
Berry Phase ◽  
Uv Light ◽  
Fdtd Method ◽  
Numerical Aperture ◽  
Limited Range ◽  
Unit Cell ◽  
Dielectric Constants ◽  
Phase Method ◽  
Frequency Range

AbstractThe investigation on metalenses have been rapidly developing, aiming to bring compact optical devices with superior properties to the market. Realizing miniature optics at the UV frequency range in particular has been challenging as the available transparent materials have limited range of dielectric constants. In this work we introduce a low absorption loss and low refractive index dielectric material magnesium oxide, MgO, as an ideal candidate for metalenses operating at UV frequencies. We theoretically investigate metalens designs capable of efficient focusing over a broad UV frequency range (200–400 nm). The presented metalenses are composed of sub-wavelength MgO nanoblocks, and characterized according to the geometric Pancharatnam–Berry phase method using FDTD method. The presented broadband metalenses can focus the incident UV light on tight focal spots (182 nm) with high numerical aperture ($$\hbox {NA}\approx 0.8$$ NA ≈ 0.8 ). The polarization conversion efficiency of the metalens unit cell and focusing efficiency of the total metalens are calculated to be as high as 94%, the best value reported in UV range so far. In addition, the metalens unit cell can be hybridized to enable lensing at multiple polarization states. The presented highly efficient MgO metalenses can play a vital role in the development of UV nanophotonic systems and could pave the way towards the world of miniaturization.

Integrated (Pb,La)(Zr,Ti)O3 Heterostructure Waveguide Devices Fabricated by Solid-Phase Epitaxy

1999 ◽  
Vol 597 ◽  
Author(s):  
K. Nashimoto ◽  
S. Nakamura ◽  
H. Moriyama ◽  
K. Haga ◽  
M. Watanabe ◽  
...  
Keyword(s):  
Low Voltage ◽  
Solid Phase ◽  
Wet Etching ◽  
Propagation Loss ◽  
Beam Deflection ◽  
Solid Phase Epitaxy ◽  
Te Mode ◽  
Tm Mode ◽  
Electro Optic ◽  
Channel Waveguides

AbstractHeterostructures of a Pb(Zr,Ti)O3 (PZT) waveguide/(Pb,La)(Zr,Ti)O3 (PLZT) system buffer layer were grown on a Nb-doped SrTiO3 (Nb:ST) substrate by solid-phase epitaxy. The propagation loss in the PLZT heterostructure waveguides was on the order of I dB/cm. An electro-optic beam deflection device with an ITO prism electrode on the surface of the PLZT heterostructure waveguide presented efficient deflection of the coupled laser beam by applying a voltage between the electrode and the substrate. A beam deflection greater than 10 mrad at 5 V and frequency response as fast as 13 MHz were observed. An apparent electro-optic coefficient as large as 39 pmJV was estimated from the deflection characteristics for the TE mode and TM mode suggesting the polarization independent nature of the PZT waveguide. For integrating the electrooptic PLZT heterostructure waveguides, channel waveguides were fabricated in the PZT waveguides using a simple wet-etching process. Based on a low-voltage drive structure, lowloss waveguide process, and fine patterning process, a fabricated digital matrix switch showed a – 10 dB cross-talk at a voltage as low as 7.5 V.

Shallow subsurface mapping by electromagnetic sounding in the 300 kHz to 30 MHz range: Model studies and prototype system assessment

Geophysics ◽  
1994 ◽  
Vol 59 (8) ◽  
pp. 1201-1210 ◽  
Author(s):  
Duff C. Stewart ◽  
Walter L. Anderson ◽  
Thomas P. Grover ◽  
Victor F. Labson
Keyword(s):  
Dielectric Permittivity ◽  
High Frequency ◽  
Low Frequency ◽  
Computer Programs ◽  
Thin Layers ◽  
Depth Range ◽  
Frequency Range ◽  
Model Studies ◽  
New Instrument ◽  
Displacement Currents

A new instrument designed for frequency‐domain sounding in the depth range 0–10 m uses short coil spacings of 5 m or less and a frequency range of 300 kHz to 30 MHz. In this frequency range, both conduction currents (controlled by electrical conductivity) and displacement currents (controlled by dielectric permittivity) are important. Several surface electromagnetic survey systems commonly used (generally with frequencies less than 60 kHz) are unsuitable for detailed investigation of the upper 5 m of the earth or, as with ground‐penetrating radar, are most effective in relatively resistive environments. Most computer programs written for interpretation of data acquired with the low‐frequency systems neglect displacement currents, and are thus unsuited for accurate high‐frequency modeling and interpretation. New forward and inverse computer programs are described that include displacement currents in layered‐earth models. The computer programs and this new instrument are used to evaluate the effectiveness of shallow high‐frequency soundings based on measurement of the tilt angle and the ellipticity of magnetic fields. Forward model studies indicate that the influence of dielectric permittivity provides the ability to resolve thin layers, especially if the instrument frequency range can be extended to 50 MHz. Field tests of the instrument and the inversion program demonstrate the potential for detailed shallow mapping wherein both the resistivity and the dielectric permittivity of layers are determined. Although data collection and inversion are much slower than for low‐frequency methods, additional information is obtained inasmuch as there usually is a permittivity contrast as well as a resistivity contrast at boundaries between different materials. Determination of dielectric permittivity is particularly important for hazardous waste site characterization because the presence of some contaminants may have little effect on observed resistivity but a large effect on observed permittivity.

scholarly journals Layered THz waveguides for SPPs, filter and sensor applications

2019 ◽  
Vol 48 (4) ◽  
pp. 567-581 ◽  
Author(s):  
Jiamin Liu ◽  
Zia Ullah Khan ◽  
Siamak Sarjoghian
Keyword(s):  
Refractive Index ◽  
Layered Structure ◽  
Dielectric Slab ◽  
Low Loss ◽  
Sensor Applications ◽  
Te Mode ◽  
Tm Mode ◽  
Mode Characteristics ◽  
Plasmon Polaritons ◽  
Thz Waveguides

Abstract Theory of five kinds of layered structure THz waveguides is presented. In these waveguides, the modified and hybrid THz surface plasmon-polaritons (SPPs) are researched in detail. On these modes, the effects of material in each layer are discussed. The anti-resonant reflecting mechanism is also discussed in these waveguides. The mode characteristics of both TM mode and TE mode are analyzed for guiding TM mode with low loss and TE modes with huge loss in one waveguide: the TE modes filter application is put forward. The mode characteristics for one waveguide have useful sensor applications: for TE1 mode, we find that the low cut-off frequency has a sensitivity (S) to the refractive index of the dielectric slab. The highest S can be 666.7 GHz/RIU when n2 = 1.5, w = 0 and t = 0.1 mm. We believe these results are very useful for designing practical THz devices for SPPs, filter and sensor applications.

Natural-frequency concept utilized in remote probing of the earth

2003 ◽  
Vol 81 (4) ◽  
pp. 705-712 ◽  
Author(s):  
S T Bishay ◽  
O M Abo-Seida ◽  
G M Sami
Keyword(s):  
Natural Frequency ◽  
Analytical Form ◽  
Step Response ◽  
Earth Model ◽  
Induced Voltage ◽  
Diagnostic Features ◽  
Vertical Magnetic Dipole ◽  
Remote Probing ◽  
Displacement Currents ◽  
Layered Ground

The complete time-domain fields due to a vertical magnetic dipole on the surface of a two-layered earth model are derived in an analytical form using the natural-frequency concept. In these expressions, the displacement currents in the earth's layers are taken into consideration. The step responses of the induced voltage in a horizontal receiving loop is found to have definite diagnostic features for the ground beneath. These features are demonstrated by numerical results and shown by figures. The clear distinction between the step response of the homogeneous and the two-layered ground suggests that this response can be used for the detection of the stratification. PACS Nos.: 41.20.Jb, 42.25.Bs, 42.25.Gy, 44.05.+e

AN APPARATUS FOR THE MEASUREMENT OF DIELECTRIC CONSTANTS OF ADSORBED GASES AT FREQUENCIES UP TO 100 Mc./Sec.

1955 ◽  
Vol 33 (2) ◽  
pp. 268-278 ◽  
Author(s):  
M. H. Waldman ◽  
R. McIntosh
Keyword(s):  
Sulphur Dioxide ◽  
Experimental Error ◽  
Dielectric Behavior ◽  
Dielectric Constants ◽  
Frequency Range

The design of an apparatus suitable for the measurement of dielectric constants at frequencies up to 106 Mc./sec. is shown. The apparatus was used to measure changes in capacitance with volume adsorbed for the system sulphur dioxide – rutile at about 3.5 °C. and for frequencies of 13, 36, and 106 Mc./sec. The results failed to reveal any dispersion due to the adsorbed matter in this frequency range. The dielectric behavior observed is the same, within experimental error of a few per cent, as that found by Channen and McIntosh for the same system at 3.7 Mc./sec.

scholarly journals Surface Waveguides Supporting Both TM Mode and TE Mode With the Same Phase Velocity

2016 ◽  
Vol 64 (9) ◽  
pp. 3811-3819 ◽  
Author(s):  
Mei Li ◽  
Shaoqiu Xiao ◽  
Jiang Long ◽  
Daniel F. Sievenpiper
Keyword(s):  
Phase Velocity ◽  
Te Mode ◽  
Tm Mode

Anelastic Phenomena and Cr2N Precipitation in a High Nitrogen Austenitic Steel

2010 ◽  
Vol 89-91 ◽  
pp. 485-490
Author(s):  
Paolo Deodati ◽  
Roberto Montanari ◽  
Ludovica Rovatti ◽  
Nadia Ucciardello ◽  
Andrea Carosi
Keyword(s):  
Austenitic Steel ◽  
Dynamic Modulus ◽  
Room Temperature ◽  
Discontinuous Precipitation ◽  
Phase Changes ◽  
Frequency Range ◽  
High Nitrogen ◽  
Prepared Material ◽  
Frequency Modulation Detection ◽  
Vibrating Reed

Internal friction (IF) and dynamic modulus measurements on a high nitrogen (0.8 wt%) austenitic steel in the temperature range from room temperature to 800 °C have been carried out by using a vibrating reed technique with electrostatic excitation and frequency modulation detection of flexural vibrations in the frequency range of kHz. The IF spectrum of the as-prepared material shows a broad peak superimposed to an exponentially increasing background. The discontinuous precipitation of Cr2N phase changes the characteristics of the peak. The results have been discussed by considering interstitial-substitutional (i-s) interactions.

Sign in / Sign up

Export Citation Format

Share Document