Propagation Loss Measurement of Wireless Body Area Network at 2.4 GHz and 3.35 GHz Bands

The main purpose of this work is to measure and analyze the propagation loss of the Wireless Body Area Network (WBAN) in frequency and time domain at two frequency bands, namely 2.4 GHz band with 80 MHz bandwidth and 3.35 GHz band with 500 MHz bandwidth. Four different scenarios (front to front, front to back, front to off-body node and back to off-body node) using many antenna´s locations on the body are used to investigate the channel response (path loss) of WBAN. It is found that the front to front channels and the front to off-body node channels have a low fading. The front to back channels and the back to off-body node channels have a high fading that can be approximated by the Distorted Rayleigh fading. Thus the WBAN range for the front to off-body node scenario is more than the range of the back to off-body node scenario.

     

Electromagnetic Wave Absorption Properties of La-Doped Strontium M-Type Hexagonal Ferrite in a 18–40 GHz Frequency Range

Journal of Electronic Materials - This article examines the performance of the M-type lanthanum-doped strontium hexaferrite with general formula Sr1–yLayFe12O19 (y?=?0.00, 0.10,...     

Experimental evaluation of prefiltering for 56 Gbaud DP-QPSK signal transmission in 75 GHz WDM grid

We investigate optical prefiltering for 56 Gbaud (224 Gbit/s) electrical time-division multiplexed (ETDM) dual polarization (DP) quaternary phase shift keying (QPSK) transmission. Different transmitter-side optical filter shapes are tested and their bandwidths are varied. Comparison of studied filter shapes shows an advantage of a pre-emphasis filter. Subsequently, we perform a fiber transmission of the 56 Gbaud DP QPSK signal filtered with the 65 GHz pre-emphasis filter to fit the 75 GHz transmission grid. Bit error rate (BER) of the signal remains below forward error correction (FEC) limit after 300 km of fiber propagation.     

Design of Metamaterial Antenna for 2.4 GHz WiFi Applications

Wireless Personal Communications - In this paper, Antenna is an evergreen field of research because of its never-ending demand in the modern communication era. In this paper metamaterial antenna is...     

Temperature-Induced Self-Decomposition Doping of Fe3GeTe2 to Achieve Ultra-High Tc of 496 K for Multispectral Compatible Strong Electromagnetic Wave Absorption

Fe₃GeTe₂ provides an ideal system for the study of itinerant ferromagnetism. However, the Curie temperature (Tc) below room temperature limits its further in-depth research and wide applications. Here, the Tc of 224 K for Fe₃GeTe₂ is greatly increased to 496 K for Fe₃GeTe₂/FeTe₂/Fe₃Ge by temperature-induced self-decomposition doping, contributing to improve the electromagnetic response for enhancing the absorption strength and bandwidth and boosting application potentials at higher temperatures. Then, to achieve the multispectral compatible strong absorption, room temperature ferromagnetic dielectric graphene@Fe₃GeTe₂/FeTe₂/Fe₃Ge absorber with 3D porous network structure is prepared by synergistic self-assembly. It has high Tc of 443 K with strong electromagnetic synergistic loss, achieving reflection loss of −61 dB at 12.6 GHz. Moreover, its absorption loss in the terahertz band (0.1–1.6 THz) is 76 dB, and the average loss is greater than 50.4 dB. Furthermore, the absorber is very potential as stealth skin to efficiently reduce satellite RCS with a multi-angle and multi-band manner in the gigahertz and terahertz bands, thus achieving the purpose of stealth. Compared with the reported conventional absorbers, the absorber has a multispectral compatible strong absorption performance covering gigahertz and terahertz bands, thus very promising for electromagnetic protection of electromagnetic communication and space vehicles.     

Very low leakage InGaAs/InAlAs pHEMTs for broadband (300 MHz to 2 GHz) low-noise applications

This paper presents the design, fabrication and characterisation of InGaAs–InAlAs high electron mobility transistors (pHEMTs) suitable for low-frequency LNA designs. Very low levels of leakage, in the order of 0.05 A/cm², are demonstrated by the pHEMTs, which have enabled the implementation of large-geometry, low-noise devices. Transistors with gate widths ranging from 200 μm to 1.2 mm are demonstrated to operate up to frequencies of 30 GHz. These are extremely promising as LNA components for implementation in broadband low-frequency systems as the very low-noise resistance simplifies matching requirements. The levels of leakage observed in our transistors further support the potential of the InGaAs/InAlAs material system as an alternative to Si when the CMOS roadmap comes to an end.     

High-performance 2 mm gate width GaN HEMTs on 6H-SiC with output power of 22.4 W @ 8 GHz

Optimized AlGaN/AlN/GaN high electron mobility transistors (HEMTs) structures were grown on 2-in. semi-insulating (SI) 6H-SiC substrate by metal–organic chemical vapor deposition (MOCVD). The 2-in. HEMT wafer exhibited a low average sheet resistance of 305.3 Ω/sq with a uniformity of 3.85%. The fabricated large periphery device with a dimension of 0.35 μm × 2 mm demonstrated high performance, with a maximum DC current density of 1360 mA/mm, a transconductance of 460 mS/mm, a breakdown voltage larger than 80 V, a current gain cut-off frequency of 24 GHz and a maximum oscillation frequency of 34 GHz. Under the condition of continuous-wave (CW) at 8 GHz, the device achieved 18.1 W output power with a power density of 9.05 W/mm and power-added-efficiency (PAE) of 36.4%. While the corresponding results of pulse condition at 8 GHz are 22.4 W output power with 11.2 W/mm power density and 45.3% PAE. These are the state-of-the-art power performance ever reported for this physical dimension of GaN HEMTs based on SiC substrate at 8 GHz.     

Tailoring the Plasmonic Modes of a Grating‐Nanocube Assembly to Achieve Broadband Absorption in the Visible Spectrum

Engineered metal‐dielectric‐metal nanostructures with broadband absorbing properties in the visible spectral range are fabricated by combining the plasmonic resonances of different noble metal nanostructures. Silver nanocubes and gold nanogratings couple to each other using a dielectric polymer spacer with controllable thickness, resulting in a large multiplicative enhancement of absorption properties across a broad spectral range. Narrow, long nanogrooves in a gold film are first fabricated using electron beam lithography, after which a polymer spacer layer with a controllable thickness ranging from 4 to 12 nm is assembled by spin‐assisted layer‐by‐layer assembly. Finally, silver nanocubes with different surface coverages ranging from 12% to 22% are deposited using the Langmuir–Blodgett technique. The individual plasmon resonances of these different nanostructures are located at significantly different optical frequencies and are tuned in this study to allow a significant increase of light absorbance of the original gratings to an average value of 84% across the broad wavelength range of 450–850 nm.     

Demonstrations of 10 and 40 Gbps upstream transmissions using 1.2 GHz RSOA-based ONU in long-reach access networks

Carrier-distributed long-reach passive optical network (LR-PON) is a promising candidate for future access networks. In this work, we analyze and compare the 4 × 2.5 Gb/s and 4 × 10 Gb/s upstream traffics in a carrier-distributed LR-PON using four wavelength-multiplexed 2.5 Gb/s on–off keying (OOK) and 10 Gb/s optical orthogonal frequency division multiplexing-quadrature amplitude modulation (OFDM-QAM) signals. Four commercial 1.2 GHz bandwidth reflective semiconductor optical amplifiers (RSOAs) are used in each optical networking unit (ONU) for the generation of the upstream signal. Due to the limited bandwidth of the RSOA, only up to 2.5 Gb/s upstream OOK signal can be generated. However, by using the spectral efficient modulation, such as OFDM-QAM, 10 Gb/s data rate can be achieved. 20, 50 and 75 km fiber transmissions are also compared using the two different kinds of modulation respectively.     

Design of Simulation System for LTE-U Using 5 GHz Band in MATLAB

Wireless Personal Communications - Unused spectrum is being a limited commodity for the telecom industry. However, up to 500 MHz of unlicensed spectrum in 5 GHz band is in use for...     

Implementation of plug-and-play ESD protection in 5.5 GHz 90 nm RF CMOS LNAs—Concepts, constraints and solutions

Design and implementation of ESD protection for a 5.5 GHz low noise amplifier (LNA) fabricated in a 90 nm RF CMOS technology is presented. An on-chip inductor, added as “plug-and-play”, is used as ESD protection for the RF pins. The consequences of design and process, as well as, the limited freedom on the ESD protection implementation for all pins to be protected are presented in detail. Enhancement in the ESD robustness using additional core-clamp diodes is proposed.     

20 GHz on-chip measurement of ESD waveform for system level analysis

Reliability of embedded electronic products is a challenging issue regarding ElectroStatic Discharge (ESD) events into real live applications. This is strongly related to the increased number of embedded systems and to technologies shrinking that result in less robust chips. To ensure the safety of electronic systems, the ESD events have to be taken into account at first design phase. But equipment manufacturers are facing the dilemma that no information is provided by the semiconductor manufacturers. At the same time Integrated Circuit (IC) designers have to take into account the final application environment to build the ESD protection strategy. Depending on the external components (external means around the chip) the on-chip current path could change. Understanding how the system environment impacts the current path within the chip is needed. This paper deals with on-chip oscilloscope developed for in-situ measurement of real ESD event in 65 nm CMOS technology. The measurement bandwidth of the embedded sampler is 100 GHz, and 20 GHz for the probes. Thanks to this technique, impact of the system on the current path of the on-chip ESD strategy will be observed. Some measurement results during an ESD stress on an I/O structure will be presented and analyzed showing that PCB trace and package induce the creation of new current paths.     

Measurement and analysis of Wi-MAX channel in 3.3 GHz using minimal-ray fading model

Wireless Networks - This paper presents minimal-ray a sum-of-sinusoids fading model with one direct signal and multipath signal as minimum as three in number, having phase, attenuation, and time of...     

Frequency-Dependent Absorption of Electromagnetic Energy in Biological Tissue

The frequency-dependent absorption of electromagnetic energy in biological tissue is illustrated by use of the Debye equations, model calculations for different irradiation conditions, and measured electrical properties (conductivity and permittivity) of different tissues. Four separate irradiation conditions are treated for calculating the power absorbed. in a given tissue when it forms a flat interface or is surrounded by another tissue. The calculations show that the greatest differential absorption occurs at frequencies between the dominant relaxation frequencies in the two tissues. From rat mammary gland tumor data, the calculations show an optimum frequency range of about 100-500 MHz for microwave hyperthermia treatment of at least these types of tumor.     

Electromagnetic Absorption in a Multilayered Model of Man

A multilayered planar model is used to examine the dependence of whole-body power absorption on the configuration of surface layers, e.g., skin, fat, and muscle which normally occur in biological bodies. It is found that the layering resonance for three-dimensional bodies (as opposed to the geometrical resonance) can be predicted quite accurately by a planar model. Calculations for a multilayered prolate spheroidal model of man predict a whole-body layering resonance at 1.8 GHz with a power absorption 34 percent greater than that predicted by a homogeneous model.     

Electromagnetic Absorption in Multilayered Cylindrical Models of Man

The absorption characteristics of multilayered cylindrical models of man irradiated by a normally incident electromagnetic plane wave are investigated. Numerical calculations for a specific skin-fat-muscle cylindrical model of man predict a layering resonance at 1.2 GHz with an average specific absorption rate (SAR) about double that calculated for the corresponding homogeneous model. The layering resonance frequency is found to be the same for incident waves polarized parallel and perpendicular to the cylinder axis. The effects of layers on whole-body absorption by man are determined by averaging the effects obtained for many combinations of skin and fat thicknesses. Absorption effects due to clothing are also investigated.     

An Enhanced Low Noise Amplifier Circuit at 6 GHz Center Frequency and NF Improvement in 180 nm CMOS Process

Wireless Personal Communications - This paper presents the design and simulation of a modified CMOS low noise amplifier (LNA) circuit in 180 nm CMOS standard technology. We modified a...     

A 125 GHz millimeter-wave phase lock loop with improved VCO and injection-locked frequency divider in 65 nm CMOS process

In this paper, a CMOS mm-wave phase locked loop (PLL) with improved voltage controlled oscillator (VCO) and injection-locked frequency divider (ILFD) at operational harmonic frequency 125 GHz is presented. The VCO structure uses the bulk effective and MOS varactor capacitor to adjust parasitic capacitor of the cross coupled pair. It obtains 2th harmonic frequency with 24% tuning range (110–140 GHz) by applying?±?1.2 V input voltage variation. The divide-by-4 ILFD circuit uses a cross coupled VCO with three injection transistors acting in linear and nonlinear regions. The frequency dividers such as divided-by-4 ILFD, subsequent current mode logic (CML) and true single phase clock (TSPC) as divider chain with ratio 1/256 are used to synthesize frequency 244 MHz which is compared to reference frequency, 244 MHz in the PLL. Simulation results of the proposed PLL circuit are obtained after extracting post layout (with total chip size of 0.29 mm²) in 65 nm CMOS standard technology and @ 1.2 V power supply voltage. The obtained results confirm theoretical relations and indicate that the proposed circuit has good figure of merit (FoM), and higher tuning range and lower die area than the recent designs.

     

Electromagnetic radiation from ingested sources in the human intestine between 150 MHz and 1.2 GHz

The conventional method of diagnosing disorders of the human gastro-intestinal (GI) tract is by sensors embedded in cannulae that are inserted through the anus, mouth, or nose. However, these cannulae cause significant patient discomfort and cannot be used in the small intestine. As a result, there is considerable ongoing work in developing wireless sensors that can be used in the small intestine. The radiation characteristics of sources in the GI tract cannot be readily calculated due to the complexity of the human body and its composite tissues, each with different electrical characteristics. In addition, the compact antennas used are electrically small, making them inefficient radiators. This paper presents radiation characteristics for sources in the GI tract that should allow for the optimum design of more efficient telemetry systems. The characteristics are determined using the finite-difference time-domain method with a realistic antenna model on an established fully segmented human body model. Radiation intensity outside the body was found to have a Gaussian-form relationship with frequency. Maximum radiation occurs between 450 and 900 MHz. The gut region was found generally to inhibit vertically polarized electric fields more than horizontally polarized fields.     

Response of Granular La1− xCaxMnO3 Film to 10 GHz and 35 GHz Frequency Electromagnetic Radiation

The nonbolometric response of La_1???xCa_xMnO₃ film to 10 GHz and 35 GHz frequency electromagnetic radiation is investigated in the case when, in addition to the strong electric field of the wave, the film is subjected to a stationary electric bias field. Dependences of responses on the radiation power P at temperature T = 80 K are presented. In the low power region, a linear dependence of the response on P is observed at both frequencies whereas for high powers the dependence behaves as ~P ^1/2. The obtained results are explained taking into account that the nonbolometric response originates from the intergranular junctions that operate in the reverse current regime. There two effects take place: (i) at low powers the detection resistance decreases with increasing power P, and (ii) at higher powers in addition to that the film resistance decreases as P ^1/2 due to the avalanche of charge carriers in the electric field of the electromagnetic wave.