This paper introduces a backscattered BLE5 transmitter for low-cost single-antenna green systems solely powered by mm-scale harvesters. Peak power reduction to 10.6 μW is achieved while enabling BLE-compliant spectral mask up to the maximum allowed backscattered power for range extension. Peak power is reduced via an approximate GFSK modulator architecture based on a non-uniform self-sampling digitally controlled oscillator (DCO) with period pruning/clustering, in place of a power-hungry Gaussian filter and PLL used in conventional GFSK modulators. A 180-nm testchip shows 97-m range with commodity receiver at 4X power and 3X range improvement with respect to prior art.

Researcher/Author:  

Karim Ali Ahmed, Ruiyuan Yang, Praveenakumar Salamani, Viveka Rajanna & Massimo Alioto

Published in:

 ESSCIRC 2023- IEEE 49th European Solid State Circuits Conference (ESSCIRC)

Date Added to IEEE Xplore: 06 October 2023

To download the paper, please proceed to:  

 10.1109/ESSCIRC59616.2023.10268708

Since heat generation in electronic devices causes thermal failure, heat dissipation is of critical importance. Furthermore, deformable devices are subjected to mechanical stress, therefore, mechanically stable thermal management material should be considered. Herein, a strategy for printable, thermally conductive, and mechanically stable composite ink for thermal management is introduced. Based on the galvanic replacement between eutectic gallium indium (EGaIn) nanoparticles and silver (Ag) flakes, decoration of the EGaIn nanoparticles on Ag flakes is resulted from the difference in standard reduction potential between Ag, Ga, and In. The resultant alloy formation(Ag–Ga or Ag–In) serves as the thermal transport junction between Ag flakes, leading to high thermal and electrical conductivity (≈140 W mK⁻¹ and ≈10⁶ S m⁻¹, respectively). In addition, owing to the polymer binder, the printed ink is mechanically stable on a substrate exhibiting stable thermal conductivity and sheet resistance under the cyclic bending test. Notably, the heat dissipation of the light-emitting diode (LED) showed better performance when applied with the developed composite ink compared to commercial Ag paste and thermal paste. The junction temperature of the LED is reduced effectively, resulting in a longer lifetime of the LED. The thermal management solution can be utilized in next-generation soft electronics.

Researcher/Author:  Hyunwoo Bark and Pooi See Lee

Published in: Advanced Functional Materials

To download the paper, please proceed to:  

https://onlinelibrary.wiley.com/doi/10.1002/adfm.202306698

A 12-bit hybrid SAR ADC with SAR search assisted by comparator offset injection is presented. The proposed ADC architecture reuses offset calibration circuitry for conversion of the last two LSBs, reducing the required capacitive DAC resolution and pushing its total capacitance down to its thermal noise limit. The proposed ADC can be calibrated without requiring any accurate input generation. The prototype ADC, fabricated in 40nm CMOS, occupying an active core area of 0.0315mm2 , and operating at 0.35-0.45V for sampling rates ranging from 0.4 to 80 kS/s respectively, achieves the lowest Walden-FOM between 0.425-0.947fJ/conv-step, with an SNDR > 64.7dB and SFDR > 74.3dB.

Researcher/Author:  

Japesh Vohra, Karim Ali Ahmed & Massimo Alioto

Published in:

ESSCIRC 2023- IEEE 49th European Solid State Circuits Conference (ESSCIRC)

To download the paper, please proceed to:  

10.1109/ESSCIRC59616.2023.10268816

We have successfully demonstrated, for the first time, an innovative back-end-of-line (BEOL) compatible electro-optic modulator and memory (EOMM) based on Lithium Niobate on Insulator (LNOI) micro-ring resonator (MRR) integrated with Ferroelectric Hafnium Zirconate Hf 0.5 Zr 0.5 O (HZO) non-volatile analog memory. High non-volatile memory and modulation performances are both achieved in a single compact device, exhibiting high extinction ratio of 13.3 dB, excellent efficiency of 66pm/V, stable nine-state switching, record-high endurance exceeding 10 ⁹ cycles.

This is accomplished by utilizing Pockels effect in LNOI, induced by electric-field effect from remnant HZO ferroelectric polarization. We studied the system implementation of reconfigurable chiplet-interposer photonic interconnect, enabled by the EOMM and EOMM with hybrid thermal-optical modulation. Our model shows a potential 70% energy efficiency improvement over conventional electrical interposer interconnect. We have also tested the integration of the EOMM with POET technologies’ 400G Tx/Rx optical interposer chip and studied a limited scale demonstration of the EOMM device.

Researcher/Author: 

Zefeng Xu, Chun-Kuei Chen, Hong-Lin Lin, Yuan Gao, Wei Ke, Baochang Xu, Pavel Dmitriev, Carlan Arbiz, Evgeny Zamburg, Steven Touzard, Xiulun Cai, James Lee, Suresh Venkatesan, Aaron Danner, Aaron Voon-Yew Thean

Published in:

2023 International Electron Devices Meeting (IEDM)

Added to IEEE Xplore: 07 February 2024

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http://dx.doi.org/10.1109/IEDM45741.2023.10413812

Cramer-Rao lower bound (CRLB) analysis for estimation of the direction of arrival (DOA) for curved receiving antenna arrays is presented. Software defined radio (SDR) measurements are used to validate the results. First the CRLB for curved arrays is derived. Then the method is applied to case studies using three different arrays for DOA estimation. The arrays with four antennas with different curvatures are fabricated and SDR is used to validate the results. It is found that the performance depends on the DOA, with the curved array providing benefits for certain directions of arrival. The proposed method can help designers of arrays for DOA estimation to improve the performance.

Researcher/Author:  Jiahao Wang, Peizhuo Yang and Koen Mouthaan

Published in: IEEE

To download the paper, please proceed to:  

https://ieeexplore.ieee.org/document/10237781

A C-band center-fed compact reflector antenna with dual linear polarization over a bandwidth of 25% is presented. To achieve this bandwidth, the feed uses a square waveguide, a polycarbonate neck, and a hat sub-reflector. The gain of the antenna is between 29 dBi and 32 dBi over the frequency range of 5–6.4 GHz. The main objective of the presented
work is to extend the operating bandwidth of the high-gain antenna while keeping the structure of the feed as simple as
possible. Measured antenna patterns, gain vs. frequency, cross polarization vs. frequency, and S-parameters of the feed are presented.

Researcher/Author: Su Yee Aye , Peng Khiang Tan , Tse Tong Chia , Sigurd Huber, and Koen Mouthaan

Published in: IEEE

To download the paper, please proceed to:  

https://ieeexplore.ieee.org/document/10238085

A stowable and deployable 4×4 bowtie array at L-band is presented. The 16 bowtie antennas are fabricated using standard FR-4. The bowtie array uses flexible copper-clad kapton with supporting narrow aluminum channels to replace the conventional rigid ground plane. A size reduction of about 85% is achieved when the antenna is stowed. The measured gain, excluding the losses of the feed network, is between 16 dBi and 19.5 dBi over the frequency band of interest from 1.2 GHz to 1.5 GHz.

Researcher/Author: Gong Chen, Fujiang Lin, and Koen Mouthaan

Published in:  IEEE

To download the paper, please proceed to:  

https://doi.org/10.1109/USNC-URSI52151.2023.10238186

By leveraging their high mobility and small size, insects have been combined with microcontrollers to build up cyborg insects for various practical applications. Unfortunately, all current cyborg insects rely on implanted electrodes to control their movement, which causes irreversible damage to their organs and muscles. Here, we develop a non-invasive method for cyborg insects to address above issues, using a conformal electrode with an in-situ polymerized ion-conducting layer and an electron-conducting layer. The neural and locomotion responses to the electrical inductions verify the efficient communication between insects and controllers by the non-invasive method. The precise “S” line following of the cyborg insect further demonstrates its potential in practical navigation. The conformal non-invasive electrodes keep the intactness of the insects while controlling their motion. With the antennae, important olfactory organs of insects preserved, the cyborg insect, in the future, may be endowed with abilities to detect the surrounding environment.

Researcher/Author: 

Qifeng Lin, Rui Li, Feilong Zhang, Kazuki Kai1, Zong Chen Ong, Xiaodong Chen  and Hirotaka Sato

Published in:  npj Flexible Electronics

To download the paper, please proceed to:  

https://www.nature.com/articles/s41528-023-00274-z

Mechanically compliant conductors are of utmost importance for the emerging fields of soft electronics and robotics. However, the development of intrinsically deformable organic conductors remains a challenge due to the trade-off between mechanical performance and charge mobility. In this study, we report a solution to this issue based on size-selective ionic crosslinking. This rationally designed crosslinking mediated by length-regulated oligo(ethylene glycol) pendant groups and metal ions simultaneously improved the softness and toughness and ensured excellent mixed ionic–electronic conductivity in poly(3,4-ethylenedioxythiophene):polystyrene sulfonate composite materials. Moreover, the added ions remarkably promoted accumulation of charge carriers in response to temperature gradient, thus offering a viable approach to stretchable thermoelectric generators with enhanced stability against humidity.

Researcher/Author:  Junwoo Lee, Hyunwoo Bark, Yazhen Xue, Pooi See Lee, and Mingjiang Zhong*

Published in:  Angewandte Chemie International Ed.  2023

To download the paper, please proceed to:  

https://doi.org/10.1002/anie.202306994