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This paper presents a novel combo-reconfigurable architecture for the frequency and radiation patterning of a novel antenna system for future fifth-generation (5G) millimeter-wave mobile communication. The tuning system independently controls the frequency and radiation pattern shifts, without letting them affect each other. The proposed antenna consists of two patches, radiating at 28 GHz and 38 GHz. A negative-channel metal–oxide–semiconductor (NMOS) transistor was used as a switch for ON/OFF states. Frequency reconfiguration was controlled by switches SD1 and SD2, while pattern reconfigurability was achieved by SD3–SD18. The desired resonant frequencies of 28 GHz and 38 GHz were achieved by varying patch dimensions through the ON and OFF states of the SD1 and SD2 switches. Similarly, parasitic stubs on the ground are used to control surface currents, which results in pattern reconfiguration. The results were analyzed for 18 different combinations of the switch states. Adding/removing parasitic stubs and switches changed the beam steering angle (by 45° shift) from 0° to 180°, which modified the stub dimensions and changed the beam-width of the main lobe.

A novel planar non-dispersive antenna for ultra-wideband radar applications is introduced. The antenna concept is based on the combination of the electromagnetic characteristics of a loop and a planar monopole. A detail discussion on the proposed antenna topology and architecture is presented, and a dedicated backfeeding technique that shows a low transmission loss over a very wide frequency band is suggested. A frequency-independent equivalent circuit of the proposed antenna, useful in the codesign and optimisation of the relevant radio frequency front end is also extracted. It is experimentally demonstrated that the considered radiating element features a fractional bandwidth of 67%, good impedance matching, reasonably constant group delay and uni-directional stable over frequency radiation patterns with front-to-back isolation of about 12 dB.

The Niigata prefecture in Japan was devastated by a large shallow earthquake ( M w 6.6, M JMA 6.8) on July 16, 2007. This earthquake has been recorded at 305 stations of Kiban Kyoshin network (KiK-net). Source model of this earthquake has been computed from accelerograms recorded by KiK-net at near-field stations surrounding source of earthquake. Several isolated wave packets were seen in recorded accelerograms at near-field stations surrounding source of this earthquake. Each wave packet in recorded accelerogram represents an isolated patch of envelope of accelerogram released from a rupture plane and is considered to be an independent source of strong motion generation area. Three different isolated wave packets have been identified within the rupture plane of the Niigata earthquake from recorded accelerograms. These isolated wave packets were considered as strong motion generation areas (SMGAs) in the rupture plane. Source parameters of each SMGA were calculated from the source displacement spectra. The approximate locations of SMGAs over the source fault were estimated using spatio-temporal variation of 48 aftershocks recorded by KiK-net and K-NET. Modified semi-empirical method has been used to simulate strong ground motion at various stations. Comparison of the observed and simulated acceleration waveforms is made in terms of root-mean-square error. Comparison of NS and EW component of observed and simulated records at eight stations confirms the suitability of final source model consisting of three SMGAs and efficacy of the modified semi-empirical technique to simulate strong ground motion.

The semiempirical approach based on envelope summation method given by Midorikawa (Tectonophysics 218:287–295, 1993 ) has been modified in this paper for modeling of strong motion generation areas (SMGAs). Horizontal components of strong ground motion have been simulated using modifications in the semiempirical approach given by Joshi et al. (Nat Hazard 71:587–609, 2014 ). Various modifications in the technique account for finite rupture source, layering of earth, componentwise division of energy and frequency-dependent radiation pattern. In this paper, SMGAs of the Uttarkashi earthquake have been modeled. Two different isolated wave packets in the recorded accelerogram have been identified from recorded ground motion, which accounts for two different SMGAs in the entire rupture plane. The approximate locations of SMGAs within the rupture plane were estimated using spatio-temporal variation of 77 aftershocks. Source parameters of each SMGA were calculated from theoretical and observed source displacement spectra computed from two different wave packets in the record. The final model of rupture plane responsible for the Uttarkashi earthquake consists of two SMGAs, and the same has been used to simulate horizontal components of acceleration records at different station using modified semiempirical technique. Comparison of the observed and simulated acceleration records in terms of root mean square error confirms the suitability of the final source model for the Uttarkashi earthquake.

In this paper, a dielectric embedded antenna with frequency and radiation pattern reconfigurable characteristic is proposed for portable terminal applications. The proposed reconfigurable antenna consists of one excitation element, two parasitic elements and eight radio frequency switches. The proposed reconfigurable functions are obtained by controlling the ON/OFF states of the radio frequency switches which are integrated into the excitation elements. As a result, the proposed reconfigurable antenna can operate at two frequencies, 1.9 GHz and 2.8 GHz for supporting DCS1800 (1.71-1.88 GHz) and UMTS (1.92-2.17 GHz), LTE2300 (2.305-2.4 GHz), LTE2500 (2.5-2.69 GHz), WIFI (2.4-2.484 GHz). The radiation pattern reconfigurable characteristic is achieved by controlling the state combination of six radio frequency switches installed on the parasitic elements, resulting in three modes in the radiation pattern at each frequency band. The experimental results demonstrated that the proposed antenna can achieve good frequency and radiation pattern reconfigurable characteristics.

We perform a strong ground motion simulation using a modified semi-empirical technique (Midorikawa in Tectonophysics 218:287–295, 1993 ), with frequency-dependent radiation pattern model. Joshi et al. (Nat Hazards 71:587–609, 2014 ) have modified the semi-empirical technique to incorporate the modeling of strong motion generation areas (SMGAs). A frequency-dependent radiation pattern model is applied to simulate high-frequency ground motion more precisely. Identified SMGAs (Kurahashi and Irikura in Earth Planets Space 63:571–576, 2011 ) of the 2011 off the Pacific coast of Tohoku earthquake ( M w  = 9.0) were modeled using this modified technique. We analyzed the effect of changing seismic moment values of SMGAs on the simulated acceleration time series. Final selection of the moment values of SMGAs is based on the root-mean-square error (RMSE) of waveform comparison. Records are simulated for both frequency-dependent and constant radiation pattern function. Simulated records for both cases are compared with observed records in terms of peak ground acceleration, peak ground velocity and pseudo-acceleration response spectra at different stations. Comparison of simulated and observed records in terms of RMSE suggests that the method is capable of simulating record, which matches in a wide frequency range for this earthquake and bears realistic appearance in terms of shape and strong motion parameters. The results confirm the efficacy and suitability of rupture model defined by five SMGAs for the developed modified technique.

This chapter contains sections titled: Introduction Effect of the Structure on the Spatial Characteristics of the Antenna Combination of Two Waves Measurements on Scaled Test Bodies Effect of Frequency on the Radiation Pattern Effect of Distance from Obstacles Effect of Wings on the Radiation Pattern Effect of the Curved Ground Plane and the Electrical Dimensions of the Fuselage Radiation Patterns on Cylinders in the Absence of Obstacles References

•First investigation of 5 G RF-EMF effects on NREM sleep spindles in genetic context.•Variant rs7304986 of CACNA1C modulates 5 G effects on spindle center frequency.•Exposure to 3.6 GHz 5 G RF-EMF accelerates spindle frequency in T/C allele carriers.•Spindle frequency in T/C carriers accelerated over widespread cortical areas.•Studies elucidating biological mechanisms underlying 5 G RF-EMF effects warranted. The introduction of 5G technology as the latest standard in mobile telecommunications has raised concerns about its potential health effects. Prior studies of earlier generations of radiofrequency electromagnetic fields (RF-EMF) demonstrated narrowband spectral increases in the electroencephalographic (EEG) spindle frequency range (11–16 Hz) in non-rapid-eye-movement (NREM) sleep. However, the impact of 5G RF-EMF on sleep remains unexplored. Additionally, RF-EMF can activate l-type voltage-gated calcium channels (LTCC), which have been linked to sleep quality and EEG oscillatory activity. This study investigates whether the allelic variant rs7304986 in the CACNA1C gene, encoding the α1C subunit of LTCC, modulates 5G RF-EMF effects on EEG spindle activity in NREM sleep. Thirty-four participants, genotyped for rs7304986 (15 T/C and 19 matched T/T carriers), underwent a double-blind, sham-controlled study with standardized left-hemisphere exposure to two 5G RF-EMF signals (3.6 GHz and 700 MHz) for 30 min before sleep. Sleep spindle activity was analyzed using high-density EEG and the Fitting Oscillations & One Over f (FOOOF) algorithm. T/C carriers reported longer sleep latency compared to T/T carriers. A significant interaction between RF-EMF exposure and rs7304986 genotype was observed, with only 3.6 GHz exposure in T/C carriers inducing a faster spindle center frequency in the central, parietal, and occipital cortex compared to sham. These findings suggest that 3.6 GHz 5G RF-EMF modulates spindle center frequency in NREM sleep in a CACNA1C genotype-dependent manner, implicating LTCC in the physiological response to RF-EMF and underscoring the need for further research into 5G effects on brain health.

High-harmonic generation (HHG) traditionally combines ~100 near-infrared laser photons to generate bright, phase-matched, extreme ultraviolet beams when the emission from many atoms adds constructively. Here, we show that by guiding a mid-infrared femtosecond laser in a high-pressure gas, ultrahigh harmonics can be generated, up to orders greater than 5000, that emerge as a bright supercontinuum that spans the entire electromagnetic spectrum from the ultraviolet to more than 1.6 kilo-electron volts, allowing, in principle, the generation of pulses as short as 2.5 attoseconds. The multiatmosphere gas pressures required for bright, phase-matched emission also support laser beam self-confinement, further enhancing the x-ray yield. Finally, the x-ray beam exhibits high spatial coherence, even though at high gas density the recolliding electrons responsible for HHG encounter other atoms during the emission process.

In this work, a dual dielectric resonator antenna (DRA) oriented in opposite directions is designed and analyzed. The unique feature of the proposed antenna is to provide dual-band filtering characteristics with a quasi-isotropic radiation pattern. The upper cylindrical ceramic is fed by the combination of a conformal strip and a circular patch, while the lower one is fed by a circular aperture. The proposed feeding mechanism produces HEM11δ and HEM12δ modes inside the ceramic material at 2.8 GHz and 5.4 GHz, respectively, providing a dual-band response. The proposed radiator has two main features: (i) the arrangement of the ceramic-based radiator creates radiation nulls at 5.8 GHz, 4.8 GHz, 3.5 GHz and 2 GHz, which provides the filtering response, and (ii) the opposite orientation of the dual ceramic produces quasi-isotropic radiation features. Experimental measurements confirm its operation in the frequency ranges of 2.48–3.3 GHz and 5.21–5.48 GHz. Maximum rejection is about −20 dBi in both frequency bands, while the passband gain is about 5.0 dBi. These radiation characteristics make the proposed antenna suitable for the WLAN (2.5 GHz/5.15 GHz) frequency band.