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Abstract This work presents a 2D tellurium (Te)‐based diode that exploits the doping achieved by atomic layer deposited (ALD) Al2O3 to enhance its rectifying performance. The proposed device comprises a Schottky junction that is dielectric‐doped to significantly reduce the reverse bias current. A boosted current responsivity four times higher compared to that of undoped devices is achieved, maximizing the performance for radio frequency (RF) power detectors. The application measurement results demonstrate sensitivities as low as −45 dBm, and at −30 dBm RF input power outstanding tangential responsivities up to 6.5 kV W–1, 4.3 kV W–1, and 650 V W–1 at 0.5, 1, and 2.5 GHz, respectively, while reaching linear dynamic range (DR) of over 30 dB. These are the highest reported values for 2D‐based material devices by almost two orders of magnitude. Furthermore, the DR is ≈10 dB larger compared to state‐of‐the‐art power detectors based on bulk semiconductors.

This work presents the analysis, design, and implementation of a fully integrated loss-compensated cascaded multistage distributed amplifier (LC-CMSDA) in $65nm$ CMOS technology. The proposed LC-CMSDA consists of three distributed stages in cascade configuration. The input stage utilizes three gain-cells in a distributive topology and offers 10 dB of gain. The second stage deploys two-sections while the output stage has three gain-sections in a distributive configuration. The interstage artificial lines are tapered towards large gain and high output power. Interstage inductive peaking in the gain-cell and high frequency loss-compensation at the gate of the cascode, extend the bandwidth. The RF chokes of all three stages have been realized on-chip that leads to a fully integrated design. Small-signal measurement results demonstrate measured peak gain of 21.5 dB and minimum gain of 9 dB through 50GHz of bandwith, resulting into a 146 GHz gain-bandwidth product. Large-signal characterization show peak saturated output power of 14.93 dBm with a peak drain efficiency of 8.95%. The third-order intercept point is better than 15 dBm. The proposed LC-CMSDA occupies only an area of $1.33~mm^{2}$ .

Abstract The research of two-dimensional (2D) Tellurium (Te) or tellurene is thriving to address current challenges in emerging thin-film electronic and optoelectronic devices. However, the study of 2D-Te-based devices for high-frequency applications is still lacking in the literature. This work presents a comprehensive study of two types of radio frequency (RF) diodes based on 2D-Te flakes and exploits their distinct properties in two RF applications. First, a metal-insulator-semiconductor (MIS) structure is employed as a nonlinear device in a passive RF mixer, where the achieved conversion loss at 2.5 GHz and 5 GHz is as low as 24 dB and 29 dB, respectively. Then, a metal-semiconductor (MS) diode is tested as a zero-bias millimeter-wave power detector and reaches an outstanding linear-in-dB dynamic range over 40 dB, while having voltage responsivities as high as 257 V ⋅ W−1 at 1 GHz (up to 1 V detected output voltage) and 47 V ⋅ W−1 at 2.5 GHz (up to 0.26 V detected output voltage). These results show superior performance compared to other 2D material-based devices in a much more mature technological phase. Thus, the authors believe that this work demonstrates the potential of 2D-Te as a promising material for devices in emerging high-frequency electronics.

This work presents the analysis, design, and implementation of an efficient and wideband active-split dual-feed distributed amplifier (AS-DFDA) in $0.13~\mu \text{m}$ CMOS technology. It consists of a dual-feed (DF) output stage with a passive combiner and an active-split (AS) input stage. The dual-feed stage is used to enhance the gain and output power of the proposed AS-DFDA by utilising both the forward and reverse gains of a conventional distributed topology. The DF stage requires an in-phase equi-amplitude signals feeding the DF gate lines from both sides which is accomplished by an active-split stage based on the split drain-line topology providing a wideband input match along with the extra leaverage in gain. An external capacitance in series with the DF stage devices is deployed to increase the cut-off frequency of the dual-feed gate lines. Further, the interstage lines are terminated with idle-line terminations on both ends to target flat gain. The amplified signal from DF stage is combined through an output impedance matched direct passive combiner. The measured results show a 13–10 dB gain from 4–22 GHz and output return loss of 6dB over the entire bandwidth. The measured output saturated power, $P_{SAT}$ , of 10.6 dBm with peak power added efficiency (PAE) of 15.1% is acheived at 5 GHz while a minimum peak PAE of 9% is obtained over the entire bandwidth. The AS-DFDA has a noise figure of 4–6 dB and occupies an active area of only $0.45\,\text {mm}^{2}$ , respectively.

Graphene has unique electrical and mechanical properties which can pave the way for new types of devices for microwave applications. However, emerging technologies often have problems with yield and still considerable variation in device parameters cause great challenges for circuit design. In this paper, we present the design and development of an integrated graphene FET amplifier addressing this challenge. A representative graphene FET was selected from a set of devices and then the input and output matching circuits were designed using the negative-image technique. The two-finger GFET with a gate length of 0.5 $\mu$m exhibit a typical $f_T$ and $f_{max}$ of 35 GHz and 37 GHz, respectively. The integrated graphene FET amplifier was fabricated on a high-resistivity silicon substrate together with thin film capacitors, airbridges, and spiral inductors. A record high gain of $4.2\,$dB at $10.6\,$GHz was measured for a single transistor amplifier stage and agrees well with simulations. These results indicate significant progress towards active microwave circuits based on emerging 2D materials.

Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere.

Abstract A high‐temperature 2.1 GHz oscillator based on a AlGaN/GaN high electron mobility transistor (HEMT) is successfully designed, implemented, and characterised for the first time. The system is explicitly designed such that the final circuit consists of a single transistor bonded to a printed circuit board (PCB), and no further passive components besides the transmission lines to attach the connectors are used. Extensive characterisation of the high electron mobility transistor has been carried out up to 300∘C in order to extract large‐ and small‐signal models. Since the system does not rely on passive tolerances and a specific model of the used transistor has been extracted, a sustainable oscillation of the design at high temperature is assured. The capabilities of the designed circuit are verified by measurements up to 230∘C, showing a promising performance with around 0 dBm output power and a phase noise of −74 dBc/Hz at 1 MHz offset at the highest characterised temperature.