The generation of RF/microwave power is required not only in wireless communications, but also applications such as jamming, imaging, RF heating, and miniature dc/dc converters. Each application has its own unique requirements for frequency, bandwidth, load, power, efficiency, linearity, cost. generated by a wide variety techniques, implementations, active devices. Power amplifiers are incorporated into transmitters similarly architectures, including linear, Kalm, envelope tracking,...

This paper presents a study of reception and rectification broad-band statistically time-varying low-power-density microwave radiation. The applications are in wireless powering industrial sensors recycling ambient RF energy. A 64-element dual-circularly-polarized spiral rectenna array is designed characterized over frequency range 2-18 GHz with single-tone multitone incident waves. integrated design the antenna rectifier, using combination full-wave electromagnetic field analysis harmonic...

This paper discusses far-field wireless powering for low-power sensors, with applications to sensing in environments where it is difficult or impossible change batteries and the exact position of sensors might not be known. With expected radio-frequency (RF) power densities 20-200- μW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> range, desired small sensor overall size, nondirective appropriate that transmit data at low duty...

This paper presents an approach and associated circuitry for harvesting near maximum output power from electromagnetic waves in the RF/microwave region of spectrum with variable incident densities range tens muW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . It is shown that open loop resistor emulation at input port a converter suitable solution tracking peak point low-power rectifying antenna source over wide RF densities. A...

For many years, wireless RF power transmission has been investigated as a viable method of delivery in wide array applications, from high-power space solar satellites to low-power sensors. However, until recently, efficient application at the low sub-milliwatt levels not realized due limitations available control circuitry. This paper presents "smart" microcontroller-based management system with online stage efficiency optimization and maximum point tracking (MPPT). The is experimentally...

A 100-MESFET oscillator which gives 21 W of CW effective radiated power (ERP) with a 16-dB directivity and 20% DC-to-RF conversion efficiency at 5 GHz is presented. The planar grid structure periodically loaded transistors. radiates the devices combine quasi-optically lock to each other. can also be injection-locked an external signal. very simple. All share same bias, they frequency tuned mirror behind or dielectric slabs in front it. An equivalent circuit for infinite predicts tuning....

A new formulation is discussed for the rigorous calculation of radiation pattern a bow-tie antenna finite length and infinitesimal thickness, placed on lossless dielectric substrate. The analysis based representation current density metal surface as sum an imposed (quasistatic) term set modes with unknown amplitudes. Free-space fields that are expressed in terms continuous spectra symmetrized plane waves matched to using method moments. resulting equations solved calculations show increasing...

Envelope tracking (ET) is by now a well-established technique that improves the efficiency of microwave power amplifiers (PAs) compared to what can be obtained with conventional class-AB or class-B operation for amplifying signals time-varying envelope, such as most those used in present wireless communication systems. ET poised deployed extensively coming generations cellular handsets because it reduce dissipation using long-term evolution (LTE) standard required fourthgeneration (4G)...

This paper discusses harvesting of low-power density incident plane waves for electronic devices in environments where it is difficult or impossible to change batteries and the exact locations energy sources are not known. As power densities vary over time space, distributed arrays antennas with optimized power-management circuits introduced increase harvested efficiency. Scaling array size, power, dc load, frequency, gain discussed through three example arrays: a dual...

Although the idea of eliminating cords seems attractive, efficiency will always be better when a wire or cable is used to deliver power. So, what are applications that warrant wireless powering, and especially powering at longer ranges? It might appropriate remember quote by Rudyard Kipling in this introduction: I keep six honest serving men (they taught me all knew) Their names What Why When And How Where Who Let us start answering main questions related powering. There essentially three...

This paper introduces a new capacitive wireless power transfer approach with the potential to significantly enhance density in large air-gap applications. enhancement is achieved through use of multiple phase-shifted plates that reduce fringing fields areas where field levels must be limited for safety reasons. The effectiveness proposed evaluated using an analytical framework and validated finite-element circuit simulations. It shown 6.78-MHz eight plate-pair system based on reduces by...

Signals designed for high-capacity communications result in high peak-to-average ratio (PAR) waveforms that the transmitter power amplifier (PA) must amplify with low distortion. With emerging fifth-generation (5G) wireless systems, carrier frequencies and signal bandwidths are expected to increase significantly from current S- C-band allocations. All these factors contributing increasingly challenging goals of maintaining PA efficiency following reasons: is not constant over output power;...

High-efficiency switched-mode (heavily saturated) circuits such as the class-E amplifier are well-known in MHz frequency range. Here, a microwave transmission-line is presented. Design equations for output circuit line lengths and impedances derived, along with approximate predicting power efficiency amplifier. Microstrip using Siemens CLY5 MESFET demonstrate 80% power-added (PAE) at 0.5 GHz 0.55 W of 73% PAE 1.0 0.94 W. Experimental results compare favorably to simplified design-oriented...

A design-oriented analysis of the microwave transmission-line class-E amplifier is presented. Experiments and harmonic-balance circuit simulations verify theoretical equations which predict class-E-amplifier output power, maximum frequency operation, dc-RF conversion efficiency. Experimental results at 0.5, 1,2, 5 GHz are At 0.5 GHz, 83% drain efficiency 80% power-added (PAE) measured, with an power 0.55 W, using Siemens CLY5 MESFET. These compared to a class-A class-F same device. 81% 72%...

The objective of this study is to develop a wireless ultrasonic structural health monitoring (SHM) system for aircraft wing inspection. In part I the (Zhao et al 2007 Smart Mater. Struct. 16 1208–17), small, low cost and light weight piezoelectric (PZT) disc transducers were bonded various parts an detection, localization growth defects. part, two approaches wirelessly interrogating sensor/actuator network developed tested. first one utilizes pair reactive coupling monopoles deliver 350 kHz...

Terahertz imaging makes it possible to acquire images of objects concealed underneath clothing by measuring the radiometric temperatures different on a human subject. The goal this work is automatically detect and segment in broadband 0.1-1 THz images. Due inherent physical properties passive terahertz associated hardware, have poor contrast low signal noise ratio. Standard segmentation algorithms are unable or objects. Our approach relies two stages. First, we remove from image using...

This paper gives an overview of measurement techniques used in the THz region electromagnetic spectrum, from about 100 GHz to several THz. Currently available components necessary for metrology, such as sources, detectors and passives, are briefly described. A discussion power measurements, vector network analysis antenna measurements well limitations these at frequencies is given. The concludes with a summary instrumentation metrology time writing.

This article overviews the motivations and challenges for non-invasive wireless measurements of internal human body temperature. Microwave radiometry is an attractive method thermometry, with possibility a wearable device that can continuously monitor temperature inside tissues in different parts body, store data, transmit it to digital medical record. Currently, there are limited number available solutions, they usually not or wireless. Here we discuss possible path implementing such...

This paper presents a study of near-field radiometry for internal temperature measurements the human body. The radiometer has Dicke architecture and operates in 1.4-GHz quiet band centimeter penetration into tissues with minimized radio frequency interference (RFI). total blackbody power from tissue stack is received by probe placed on skin, designed to receive high percentage buried layer. Temperature retrieval subsurface layers performed using weighting functions obtained full-wave...

This paper introduces a high-performance large air-gap capacitive wireless power transfer (WPT) module as part of multi-modular WPT system for electric vehicle charging. utilizes two pairs metal plates separated by an the coupler, incorporates L-section matching networks to provide gain and reactive compensation, is driven GaN-based inverter operating at 6.78 MHz. The achieves high efficiency simplicity eliminating need high-voltage capacitors, instead parasitic capacitances formed between...

The second annual Student Wireless Energy Harvesting (WEH) Design Competition was held during the 2013 IEEE Microwave Theory and Techniques Society (MTT_S) International Symposium (IMS2013) in Seattle, Washington, United States. This year, competition parameters were modified from those of last year [1], a new figure merit (FoM) established. overall goal to demonstrate low-mass hardware that can efficiently receive rectify extremely low-incident power densities at two frequencies, with fixed...

This article presents 16and 81-element broadband rectenna arrays screen printed on a cotton tee-shirt for harvesting 4-130-μW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> power densities between 2 and 5 GHz. A packaged SMS7630-079LF Schottky diode is connected with silver paint soldered to each element of the array. The impedance over frequency as function dc load input analyzed using source-pull harmonic-balance simulations....

A new multiuser terahertz (THz) measurement facility, or " <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">THz Lab</i> ," located at the New York University (NYU) wireless research center, develops a next-generation laboratory to enable pioneering upper reaches of radio spectrum: sub-THz (100–300 GHz) and THz (0.3–3 THz) frequency bands. The cellular telephone industry's recent realization viability millimeter wave (mm-wave) spectrum for 5G...

This paper describes design and implementation of a digitally controlled dc/dc converter that provides dynamically adjustable supply voltage for radio frequency power amplifier (RFPA). The techniques employed in the include combination constant-frequency continuous conduction mode (CCM) variable-frequency discontinuous to achieve very high efficiency over wide range output levels. control is accomplished using current-estimator circuit, which eliminates need current sensing. A...