T/R RF Switch with 150 ns Switching Time and over 100 dBc IMD for Wideband Mobile Applications in Thick Oxide SOI Process

This paper presents a fast-switching Transmit/Receive (T/R) Single-Pole-Double-Throw (SPDT) Radio Frequency (RF) switch. Thorough analyses have been conducted to choose the optimum number of stacks, transistor sizes, gate and body voltages, to satisfy the required specifications. This switch applies six stacks of series and shunt transistors as big as 3.9 mm/160 nm and 0.75 mm/160 nm, respectively. A negative charge pump and a voltage booster generate the negative and boosted control voltages to improve the harmonics and to keep Inter-Modulation Distortion (IMD) performance of the switch over 100 dBc. A Low Drop-Out (LDO) regulator limits the boosted voltage in Absolute Maximum Rating (AMR) conditions and improves the switch performance for Process, Voltage and Temperature (PVT) variations. To reduce the size, a dense custom-made capacitor consisting of different types of capacitors has been presented where they have been placed over each other in layout considering the Design Rule Checks (DRC) and applied in negative charge pump, voltage booster and LDO. This switch has been fabricated and tested in a 90 nm Silicon-on-Insulator (SOI) process. The second and third IMD for all specified blockers remain over 100 dBc and the switching time as fast as 150 ns has been achieved. The Insertion Loss (IL) and isolation at 2.7 GHz are −0.17 dB and −33 dB, respectively. This design consumes 145 uA from supply voltage range of 1.65 V to 1.95 V and occupies 440 × 472 µm2 of die area.

3D Printed Polymer Photonic Topological Insulators and their Robustness to Fabrication Disorder

Photonic topological insulators have emerged as an exciting new platform for backscatter-free waveguiding even in the presence of defects, with applications in robust long-range energy and quantum information transfer, spectroscopy and sensing, chiral quantum optics, and optoelectronics. We demonstrate a design for spin-Hall photonic topological insulators with remarkably low refractive index contrast, enabling the synthesis of photonic topological waveguides from polymeric materials for the first time. Our design is compatible with additive manufacturing methods, including fused filament fabrication for microwave frequencies, and constitutes the first demonstration of a 3D printed all-dielectric photonic topological insulator. We combine rapid device fabrication through 3D printing with high-speed FDTD simulation to quantify topological protection of transmission through “omega” shaped bent topological waveguides and find that one corner in the waveguide is 3-5 times more robust to disorder than the other. This dichotomy, a new empirical design rule for ℤ2 topological insulator devices, is shown to originate in the fundamental system symmetries and is illustrated via the distributions of Poynting vectors that describe energy flow through the waveguide. Taken together, our demonstration of 3D printed polymeric spin-Hall photonic topological insulators paired with quantification of robustness to disorder at bent topological interfaces provides a rapid, flexible scheme for engineering high-performance topological photonic devices across multiple frequency regimes from microwave to THz, to visible.

Design framework for polarization-insensitive multifunctional achromatic metalenses

Controlling the wavefront of light, especially on a subwavelength scale, is pivotal in modern optics. Metasurfaces present a unique platform for realizing flat lenses, called metalenses, with thicknesses on the order of the wavelength. Despite substantial effort, however, suppressing the chromatic aberrations over large operational bandwidths of metalenses still remains a challenge. Here, we develop a systematic design method enabling a simultaneous, polarization-insensitive control of the phase and the group delay of a light beam based on libraries of transmission-mode dielectric meta-elements. Mid-infrared achromatic metalenses are designed and theoretically analyzed to have diffraction-limited focal spots with vanishing chromatic aberrations in the operating wavelength range of 6–8.5 μm, while maintaining high focusing efficiencies of 41% on average. The proposed methodology, which can be used as a general design rule for all spectra, also provides a versatile design scheme for ultrashort pulse focusing and achromatic vortex-beam generation (orbital angular momentum), representing a major advance toward practical implementations of functional metalenses.

Design Rule for Constructing Buckling-Free Polymeric Stencil with Microdot Apertures

A polymeric stencil with microdot apertures made by using polydimethylsiloxane (PDMS) molds with pillar patterns has many advantages, including conformal contact, easy processability, flexibility, and low cost compared to conventional silicon-based membranes. However, due to the inherent deformability of PDMS materials in response to external pressure, it is challenging to construct structurally stable stencils with high structural fidelity. Here, we propose a design rule on the buckling pressure for constructing polymeric stencils without process failure. To investigate the critical buckling pressure (Pcr), stencils are fabricated by using different PDMS molds with aspect ratio variations (AR: 1.6, 2.0, 4.0, and 5.3). By observing the buckled morphology of apertures, the structures can be classified into two groups: low (AR 1.6 and 2.0) and high (AR 4.0 and 5.3) AR groups, and Pcr decreases as AR increases in each group. To investigate the results theoretically, the analysis based on Euler’s buckling theory and slenderness ratio is conducted, indicating that the theory is only valid for the high-AR group herein. Besides, considering the correction factor, Pcr agrees well with the experimental results.

FARUL3S: a New Framework for Agile Regulated Ultra-Large-Scale Software Systems

<div>The Ultra-Large-Scale Software (ULSS) systems development challenges today’s software management and development approaches. Northrop et al. (2006) revealed three broad areas of challenges [1]. To deal with those challenges, they propose an interdisciplinary portfolio of research. In particular, we address the design and evolution challenge by focusing on the design area of research. In order to regulate the ULSS systems, the traditional software engineering tools face challenges as they are top-down so they deal with each domain model separately. To address the domain diversity like in the smart city systems, we propose the Framework for Agile Regulated Ultra Large Scale Software System (FARUL3S) to look at the ULSS system from bottom-up. The FARUL3S is a user-centered solution that aims at combining the complex adaptive system, the financial economics as well as the engineering systems design. Our contribution aims to regulate and constrain the ULSS systems by using architectural agreements and other rules. In this paper, we provide a detailed description of the FARUL3S steps. Our Framework generates a system Design Rule Hierarchy (DRH) so it can be used to constrain the entire system design. In the future, we will provide an illustration of the FARUL3S adoption on the management and design of different smart city services to ensure the efficiency of our solution.</div>

Anisotropic charge trapping in phototransistors unlocks ultrasensitive polarimetry

Being able to probe the polarization states of light is crucial for applications from medical diagnostics and bio-inspired navigation to information encryption and quantum computing. Current state-of-the-art polarimeters based on anisotropic semiconductors enable direct linear dichroism photodetection without the need for bulky and complex external optics. However, their polarization sensitivity is restricted by the inherent optical anisotropy, leading to low dichroic ratios of typically smaller than ten. Here, we unveil an effective and general design rule to achieve a more than 2,000-fold enhanced polarization sensitivity by exploiting a light-induced anisotropic gating effect in organic phototransistors. The polarization-dependent trapping of photogenerated charge carriers provides an anisotropic photo-induced gate for current amplification, which has resulted in an extremely high dichroic ratio of over 1.2×104, more than two orders of magnitude higher than any previous reports. These findings further enable the first demonstration of a novel miniaturized bionic celestial compass for skylight-based polarization navigation. Our results offer a fundamental design principle and a new route for the development of next-generation highly polarization-sensitive optoelectronics.

Reorganization energies of flexible organic molecules as a challenging target for machine learning enhanced virtual screening

The molecular reorganization energy $\lambda$ strongly influences the charge carrier mobility of organic semiconductors and is therefore an important target for molecular design. Machine learning (ML) models generally have the potential to strongly accelerate this design process (e.g. in virtual screening studies) by providing fast and accurate estimates of molecular properties. While such models are well established for simple properties (e.g. the atomization energy), $\lambda$ poses a significant challenge in this context. In this paper, we address the questions of how ML models for $\lambda$ can be improved and what their benefit is in high-throughput virtual screening (HTVS) studies. We find that, while improved predictive accuracy can be obtained relative to a semiempirical baseline model, the improvement in molecular discovery is somewhat marginal. In particular, the ML enhanced screenings are more effective in identifying promising candidates but lead to a less diverse sample. We further use substructure analysis to derive a general design rule for organic molecules with low $\lambda$ from the HTVS results.

Non-fluorinated non-solvating cosolvent enabling superior performance of lithium metal anode battery

Lithium–ion solvation governs the performance of lithium metal anode (LMA) by tuning its interfacial stability. Solvation degree is modulated by adopting fluorinated non-solvating cosolvents (FNSC) to induce anion-rich solvation structure which is beneficial in constructing mechanically stable interface to suppress lithium dendrite. However, FNSC exhibits low cathodic stability owing to their low lowest unoccupied molecular orbital (LUMO) level, aggravating long-term cycling of LMA. We establish that spectroscopically measured Lewis basicity and polarity are critical parameters for designing optimal non-solvating cosolvents. Non-fluorinated non-solvating cosolvents (NFNSC) proposed by our design rule (i.e. anisole, ethoxybenzene and furan) delivered 99.0 % coulombic efficiency over 1400 cycles. In these molecules, the aromatic ring delocalizes oxygen electron pairs and lowers solvation capability, confirmed by electrochemical cycling, Raman spectroscopy, and DFT binding energy calculation. Finally, the quantification of remaining NFNSC in the electrolytes using nuclear magnetic resonance spectroscopy proves their reductive stability for extended cycles.

Resonant scanning design and control for fast spatial sampling

Two-dimensional, resonant scanners have been utilized in a large variety of imaging modules due to their compact form, low power consumption, large angular range, and high speed. However, resonant scanners have problems with non-optimal and inflexible scanning patterns and inherent phase uncertainty, which limit practical applications. Here we propose methods for optimized design and control of the scanning trajectory of two-dimensional resonant scanners under various physical constraints, including high frame-rate and limited actuation amplitude. First, we propose an analytical design rule for uniform spatial sampling. We demonstrate theoretically and experimentally that by expanding the design space, the proposed designs outperform previous designs in terms of scanning range and fill factor. Second, we show that we can create flexible scanning patterns that allow focusing on user-defined Regions-of-Interest (RoI) by modulation of the scanning parameters. The scanning parameters are found by an optimization algorithm. In simulations, we demonstrate the benefits of these designs with standard metrics and higher-level computer vision tasks (LiDAR odometry and 3D object detection). Finally, we experimentally implement and verify both unmodulated and modulated scanning modes using a two-dimensional, resonant MEMS scanner. Central to the implementations is high bandwidth monitoring of the phase of the angular scans in both dimensions. This task is carried out with a position-sensitive photodetector combined with high-bandwidth electronics, enabling fast spatial sampling at $$\sim 100$$ ∼ 100 Hz frame-rate.