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.

     

Measurements of Human Body Attenuation and Dual Polarized Diversity Gain for 38 GHz Millimeter-Wave Channel

Wireless Personal Communications - Due to the increasing demand for higher bandwidth in modern communication systems, conventional networks are continuously expanded with new technologies to...     

Large-scale channel characterization at 28 GHz on a university campus in the United Arab Emirates

Telecommunication Systems - Millimeter wave (mm-wave) communication is one of the key enabling technologies for meeting the requirements of the fifth generation (5G) wireless communication systems....     

Measurements at 2.4, 3.4, 5.2, 28 and 60 GHz for Device-to-Device Wireless Communications

Wireless Personal Communications - Wireless communication networks with increased demand for higher speed in data transfer have paved way for device-to-device (D2D) wireless communications. This...     

Characteristics of High-Power Breakdown at 28 GHz

Characteristics of arcs resulting from high-power breakdown in a waveguide at 28 GHz were detemined as a function of CW power level. The radio frequency power reflected from and absorbed in arcs as well as the arc velocity were measured. In addition, the spectrum of the arc light and the track on the surface in a waveguide caused by an arc were evaluated. Comparing the velocity of an arc at 28 GHz with that at about 10 GHz, it was found that the velocity of the arc is proportional to the square of the electric field strength but depends very little on radio frequency.     

Tailoring of Electromagnetic Absorption in Substituted Hexaferrites from 8.2 GHz to 12.4 GHz

Journal of Electronic Materials - Microwave absorbers are an important topic of interest to mitigate electromagnetic interference. Here, we have investigated electromagnetic absorption properties...     

Network Planning for Deep Fading Area at 1.8 GHz LTE Network

Wireless Personal Communications - In the current scenario path loss, coverage and capacity by operating network under fading condition is research challenge. In this paper, signal strength of long...     

Rough surface scattering from exterior walls at 28 GHz

In this study we investigated the Local Multipoint Distribution Service band (28 GHz) rough surface scattering properties of limestone and brick walls. Our ultimate goal is to understand the characteristics of radio paths that involve one or more bounces from these walls. In the experiment described here, we processed impulse response data to produce power delay profiles and calculate relevant channel metrics. In particular, we investigated the scattered signal behavior for different incident angles and transmitter-receiver geometries. Using the reflected pulse width and maximum excess delay derived from each power delay profile, we found that limestone and brick walls exhibited measurable diffuse scattering. The reflected pulse from a limestone wall has more maximum excess delay spread than does a brick wall at the -15 dB power threshold. The mean maximum excess delay for the reflected pulse for the limestone wall measurement configurations was more than twice that of the brick wall. With equal transmitter and receiver distances to the wall, we found that the maximum excess delay decreased and the perpendicular reflection coefficient increased with incident angle.     

28 GHz下对毫米波透射特性的分析

毫米波段拥有高速传输数据的优点,是目前第5代(the 5th Generation,5G)移动通信系统的重要候选频段之一.为了研究毫米波的透射特性,将一对喇叭天线相向放置在玻璃门的两侧,在28 GHz频率下使用800 MHz带宽设备进行了一系列透射特性的测量.研究了不同入射角,极化方式及不同发射端与接收端(Transmitter-Receiver,Tx-Rx)距离对透射系数的影响.将测量结果与菲涅耳传播定律(包括光滑表面和提出的高斯粗糙表面模型)进行了对比.结果表明,文中提出的高斯粗糙表面模型与垂直和水平极化信号的透射特性更拟合.此外,实验也研究了收发端距离对透射的影响,并得出了不同入射角度下的穿透损耗值.     

Optimization of a Novel Rectenna for RF Energy Harvesting at 2.45 GHz

In this work, the different elements of a rectenna were optimized for the energy harvesting from Wi-Fi at 2.45 GHz, using the particle swarm optimization method with real or hybrid dimensions depending on the element. The antenna was optimized in different steps and for each one the effect on its performance was determined. For the rectifier, several commercial diodes were compared for evaluating the best selection for this application. Additionally, a low pass filter and an impedance matching of L-section were implemented as coupling elements. The antenna from the novel rectenna had a gain equal to 4.42 dBi due to the incorporation of a pixeled metasurface structure in the ground layer, and a maximum conversion efficiency of 73% with the diode SMS-7630. In this sense, the optimized rectenna presented a better performance than others from the literature for RF energy harvesting at 2.45 GHz. Therefore, the proposed rectenna can be a good alternative as a power supply in nodes of wireless sensor networks with the addition of the DC–DC boost converter LTC3105.

     

A GaN HEMT Class F Amplifier at 2 GHz With > 80% PAE

A Class F amplifier has been designed, fabricated, and tested using a GaN HEMT transistor and hybrid printed circuit board (PCB) packaging. The amplifier has a peak power-added efficiency (PAE) of 85% with an output power of 16.5 W. A gate-connected field-plated and a source-connected field-plated device of the same size and layout were measured in this topology. An output power and drain efficiency tradeoff, dependant on the drain impedance at the fundamental frequency due to the on-state resistance, is explored. A comparison between Class F and Inverse F, given particular operating conditions for this device, is made.     

Channel Modeling Optimization Based on Measurements at 26 GHz in an Open Office

Wireless Personal Communications - In this paper, based on channel measurements at 26 GHz in an open office, modeling approaches for joint channel parameters are proposed to find an...     

1.8 V–3 GHz CMOS limiting amplifier with efficient frequency compensation

A compact robust CMOS limiting amplifier (LA) for high data traffic optical links is presented in this work. The core considers two different blocks. First, four common-source inverter amplifiers are included, which optimize the gain-bandwidth product of the structure. And second, two additional compensation stages are placed strategically between the gain stages alleviating the pernicious load effect. These stages develop two different compensation techniques simultaneously thus increasing the bandwidth. The proposed design consumes 113 mW with a single 1.8 V supply. It achieves a cut-off frequency up to 3 GHz and provides a gain of 21 dB. The circuit is packaged in a QFN24 and mounted on a commercial FR4 PCB.     

Site diversity for satellite earth terminals and measurements at 28GHz

This work reviews site diversity concepts and models and presents the results of a site diversity experiment, in which radiometers were used to measure attenuation on Earth-space paths, performed at Columbus, Ohio, for a period of one year. Attenuation statistics are presented first in the form of the joint probability density function of attenuation at the two sites. From these are derived the cumulative two-dimensional distribution of attenuation at both sites, the cumulative distribution of attenuation at each site, the effective cumulative distribution of attenuation for a diversity system that always switches to the better of two signals, and the effective cumulative distribution of attenuation for a system with maximal-ratio signal combining. The switched-system diversity gain is compared with D.B. Hodge's (1982) predictive model, and the diversity improvement is compared with L. Boithias' (Radiowave Propagation, McGraw-Hill, 1987) model. Fade-duration and interfade-interval statistics are presented for each site and for systems that use switching and maximal-ratio combining. Rain-rate and interrainfall interval statistics are included     

46 × 2.5 GHz Mode-Locked Erbium-Doped Fiber Laser With 25-GHz Spacing

We demonstrate a mode-locked, multiwavelength erbium-doped fiber laser at 2.5 GHz with 25-GHz channel spacing and that is wavelength tunable from 1545 to 1558 nm. Stable, room-temperature operation is obtained by exploiting four-wave mixing in a length of highly nonlinear fiber. At a central wavelength of 1549.5 nm, we obtain 30 wavelengths within 3 dB and 46 wavelengths within 6 dB; the full-width at half-maximum of the envelope is 85 ps.     

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 novel 5.8 GHz quasi-lumped element resonator antenna

In this paper, a novel quasi-lumped element resonator antenna is presented. The proposed antenna consists of the interdigital capacitor in parallel with a straight line inductor and is fabricated on Duroid RC4003C circuit board. The entire arrangement was fed by a coaxial feed at a frequency of 5.8 GHz. The size, bandwidth and radiation patterns were studied. The proposed antenna exhibits better impedance bandwidth and significant size reduction in comparison with similar results obtained from the conventional microstrip patch antenna with similar feeding technique and resonant frequency. The size of the proposed antenna structure is 5.8 × 5.6 mm² and experimental results are shown to be in good agreement with the design simulation.     

Compact Bioinspired Antenna for WLAN 5 GHz Application

Wireless Personal Communications - This paper presents the development of a compact monopole antenna bioinspired in the Opuntia ficus-indica plant-shape, generated by Gielis formula, built in...     

Universal MOSFET gate impedance model for 200 MHz–20 GHz frequency range

The scaling of CMOS technology to 100 nm and below and the endless pursuit of higher operating frequencies drives the need to accurately model effects such as gate leakage and the deterioration of transport characteristics that dominate at those feature sizes and frequencies. Current modeling techniques are frequency limited and require different models for different frequency ranges in order to achieve accuracy goals. In the foundry world, high frequency models are typically empirical in nature and significantly lag their low frequency counterparts in terms of availability. This tends to slow the adoption of new foundry technologies for high performance applications such as extremely high data rate serializer/deserializer (SERDES) transceiver cores. However, design cycle time and time to market while transitioning between technology nodes can be reduced by incorporating a re-usable, industry-standard model. This work proposes such a model for device gate impedance that is simulator-friendly, compact, frequency-independent, and relatively portable across technology nodes. This semi-empirical gate impedance model is based on depletion in the poly-silicon gate electrode. The model performs accurately over 200 MHz–20 GHz at different bias conditions and widths and has been verified by measured data in three technology nodes. The model and model parameter behavior are consistent across technology nodes thereby enabling re-usability and portability.