This article presents recent European-based contributions for wireless power transmission (WPT), related to applications ranging from future Internet of Things (IoT) and fifth-generation (5G) systems to highpower electric vehicle charging. The contributors are all members of a European consortium on WPT, COST Action IC1301 (Table 1). WPT is the driving technology that will enable the next stage in the current consumer electronics revolution, including batteryless sensors, passive RF identification (RFID), passive wireless sensors, the IoT, and machine-to-machine solutions.
Applications for space technology, test equipment, electronic warfare systems, and digital radio have made wide-band power amplifiers (WBPAs) the subject of research since 1948 , . More recently, the advent of gallium nitride (GaN) technology with its special features, such as wide bandgap, high output power capability, and high electron velocity, has attracted researchers' attention for using such technology in WBPAs .
With the development of fifth-generation (5G) network solutions and high-data communication systems, millimeter-wave frequencies are being proposed for their licensing and bandwidth benefits. E-band radios at 71-76 and 81-86 GHz have recently been developed for backhaul and fixed point-to-point applications. Typically highgain, waveguide-based antennas are used in these deployments. By utilizing polarization, data rates can be increased two-fold. Another way to increase data rates for communication systems on the hardware side is through introducing orbital angular momentum (OAM). By twisting beams, multiple orthogonal modes can travel along the same wireless channel on the same frequency. This article highlights radiators, experiments, and techniques to generate twisted waves at radio frequency (RF).
When Privates George Elliott and Jo s eph Lockard discovered a large fleet of airplanes approaching Pearl Harbor, Hawai'i, on the morning of 7 December 1941, they were operating a new U.S. Army Signal Corps radar that used the same antenna for transmitting and receiving RF energy . RF engineers had to quickly develop a variety of new techniques to keep the multikilowatt transmitter signals from degrading or damaging the sensitive receivers in those early systems. This past December marked the 75th anniversary of that event. Tying in with the exhibit of related hardware at the IEEE Microwave Theory and Techniques Society's (MTT-S) 2017 International Microwave Symposium in Honolulu this June, the goal of this article is to highlight some of the components and circuits used for transmit?receive (T/R) switching in U.S. radars from the pre-World War II era through the following few decades.
At the heart of today's communication systems lies the autonomous signal source, the oscillators. The design criteria for these are governed by a system's requirements (based on its applications). Oscillators have evolved over the past century and today offer a wide range of options with stringent specifications in terms of power consumption, performance, and cost. Optimizing for phase noise with improved overall performance is considered a key design criterion, and a figure of merit (FOM) that includes all important parameters then determines the oscillator performance -.
Nanotechnologies offer a vast number of applications due to the unique features of nanostructured materials . In the electronics field, this new technology could open innovative ways to go beyond Moore's law , but progress in manufacturing technology still limits the wide dispersion of nanotechnology-based circuits. The bridge between nanoscience and realized devices can be achieved by modeling the multiphysics phenomena at the nanoscale, which will aid in the development of the technology.