null

null

null

null

null

null

Each Society within IEEE covers a specific area of electrical engineering, defined in the Society’s field of interest (FOI) statement. For the IEEE Microwave Theory and Technology Society (MTT-S), the FOI statement reads, “The field of interest of the society shall be theory, techniques and applications of guided wave and wireless technologies spanning the electromagnetic spectrum from RF/microwave through millimeter-waves and terahertz, including the aspects of materials, components, devices, circuits, modules, and systems which involve the generation, modulation, demodulation, control, transmission, sensing and effects of electromagnetic signals” [1]. Note that the FOI statement is quite broad—and intentionally so because our field is also quite broad, covering passive and active components, circuits, and systems in a variety of applications, thus making the MTT-S the “MHz to THz community.” This broad technology space is represented and fostered by our 28 technical committees in core technologies and techniques as well as systems and applications [2]. This idea of breadth within our Society is this month’s theme for IEEE Microwave Magazine: “Breadth of MTT.” In this issue, we offer you four technical articles that are examples of the wide technological reach of our community, as well as the usual columns that you expect.

The IEEE Microwave Theory and Technology Society (MTT-S) is a global community, with 40% of its members in North America (Regions R1–R7); 22% in Europe, Africa, and Middle East (R8); 2% in Latin America (R9); and 36% in Asia and Oceania (R10) (Figure 1).

null

null

Frequent readers of this column may recall that I am fortunate to be the grandfather of the most adorable grandchild ever [1]. At this writing, he is almost 16 months old and still most adorable. He is also, unsurprisingly, the cleverest 16 month old ever.

Regular readers of the column will recall my long-standing fascination with the scientific search for extraterrestrial intelligence (SETI). Last year, I wrote about the American astrophysicist Frank Drake (1930–2022), who kickstarted SETI in 1960 with his Project Ozma [2] and whose eponymous Drake equation [3] has been used to estimate the number of observable civilizations in our galaxy. Recently, I browsed through a new crop of books devoted to SETI. They included Interstellar: The Search for Extraterrestrial Life and Our Future in the Stars [1] by the Harvard astronomer Avi Loeb; Alien Earths [4] by Lisa Kaltenegger, the director of the Carl Sagan Institute at Cornell; and The Little Book of Aliens [5] by the physicist Adam Frank of the University of Rochester. Even a cursory perusal of these books makes one thing very clear. Not only are scientists going beyond Drake’s original vision of searching for “radio waves sent forth by other intelligent civilizations” [2], but the current SETI discourse also employs many terms unfamiliar to the wider public. Here are a few of them to bring you up to speed.

null

As silicon radars have become commonplace at microwave and millimeter-wave frequencies driven by automotive and other sensing applications, two specific architectures for these radars have become dominant in the literature: frequency-multiplied radar systems [1], [2], [3], [4], [5], [6], [7], [8] and upconverted radar systems [9], [10]. While both architectures are well reported, the literature in microwave theory and technology thus far does not offer a robust quantitative comparison of the two approaches regarding their radar behavior, especially in the case of dynamic range.

Reconfigurable systems play an important role in the design of reconfigurable wireless communication systems. In the traditional approach, separate transmit and receive pathways are required for every supported communication standard/frequency band for an RF front-end architecture. However, this approach increases the complexity and size of the system. This problem can be solved by employing subsystems, or blocks, that can function across multiple frequency bands and standards or that can reconfigure themselves based on the spectrum. This flexibility can free up finite spectrum resources to enable a miniaturized system. Therefore, microwave subsystems should ideally be reconfigurable and frequency agile in order to handle the vast frequency allocation of the regulated communication bands and the multitude of standards by which these radios must function. Such subsystems would allow for the implementation of new architectures with fewer functional components. Therefore, reconfigurable circuits can be useful for several wireless applications, such as telecommunication and military applications, where new frequency bands are coming or are expected to come. A flow graph for designing reconfigurable circuits is in Figure 1.

Energy-harvesting (EH) and wireless power transmission devices using microwaves have garnered considerable attention recently. Generating energy from ambient signals or a dedicated source improves the chances of replacing conventional battery-based systems. Batteries have been the most important power source in applications where mobility is essential. These portable devices eliminated the need for extensive transmission cables and ac power outlets. From watches to automobiles, batteries reigned as the power source over many decades. However, as time goes on, the disposal of dead batteries poses a relevant concern and real threat. Harmful chemicals, such as lead, mercury, cadmium, zinc, and chromium [1], from dumped batteries can change the soil composition, which affects agriculture and, eventually, the biochain. With the evolving food chain, these harmful compounds affect the equilibrium of the entire ecosystem. Therefore, a viable replacement for battery-based devices becomes imperative.

Metamaterials [1] are artificially engineered structures that, unlike other conventional materials, are capable of manipulating the properties of an electromagnetic (EM) wave. There are three types of metamaterials: 1) single negative, where the material has either a negative permittivity value or a negative permeability value; 2) double negative, the most common type, in which both permeability and permittivity have negative values; and 3) zero index, where either ${\epsilon}$ or ${\mu}$ is zero, which leads to a zero-refractive index. In 1968, Veselago [2] studied these types of materials theoretically and discovered various fascinating properties, including the Doppler effect reversal, reversal of Snell’s law, change in the reflection properties of a concave and convex lens, and reversal of the boundary conditions used to analyze an EM wave interaction with a medium. An important characteristic of a double-negative metamaterial is its ability to support wave transmission in the reverse direction, where the phase and group velocities exhibit opposing orientations, (i.e., the incident wave direction is opposite to that of the maximum power). By employing a repetitive arrangement of thin wires with periodicity $p$ and diameter $a$, as shown in Figure 1(a), Pendry et al. [3] have obtained negative permittivity.

null

Presents reviews for the following list of books, Electromagnetics and Antenna Technology

Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.