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1. MPCast: A Novel Downlink Transmission Technology for Low Power Wide Area Networks

   https://doi.org/10.1109/ICC42927.2021.9500584  

   Zhang, Zhenghao (June 2021, ICC 2021 - IEEE International Conference on Communications)

   null (Ed.)

   In this paper, MPCast, a novel wireless transmission technology for the downlink of Low Power Wide Area Networks (LPWAN), is proposed. MPCast modulates data on the Zadoff-Chu (ZC) sequence, which generates a peak at the receiving side. Both the location and phase of the peak carry information. Also, multiple peaks are transmitted simultaneously at different power levels to be received by nodes with different channel conditions. A novel preamble design allows the nodes to detect the frame and synchronize with the AP at low computation complexity. MPCast has been validated with real-world experiments on the Powder platform. MPCast has also been evaluated with simulations under a challenging wireless channel model. The results show that MPCast achieves a physical layer data rate of 1.74 kbps in a 125 kHz channel when the Signal to Noise Ratio (SNR) is -7 dB, which is a 9 dB gain over LoRa SF 9. 

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2. Side-lobe reduction by cascading Bragg grating filters on a Si-photonic chip

   https://doi.org/10.1364/OE.446588  

   Kumar, Sushant; Alshamrani, Naif; Grieco, Andrew; Fainman, Yeshaiahu (March 2022, Optics Express)

   Bragg-grating based cavities and coupler designs present opportunities for flexible allocation of bandwidth and spectrum in silicon photonic devices. Integrated silicon photonic devices are moving toward mainstream, mass adoption, leading to the need for compact Bragg grating based designs. In this work we present a design and experimental validation of a cascaded contra-directional Bragg-grating coupler with a measured main lobe to side-lobe contrast of 12.93 dB. This level of performance is achieved in a more compact size as compared to conventional apodized gratings, and a similar design philosophy can be used to improve side-lobe reduction in grating-based mirror design for on-chip lasers and other cavity-based designs as well. 

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3. Grating Lobe Mitigation in Scanning Planar Phased Array Antennas

   https://doi.org/10.1109/PAST43306.2019.9020996  

   Iqbal, Zabed; Pour, Maria (March 2020, 2019 IEEE International Symposium on Phased Array System & Technology (PAST))

   null (Ed.)

   This paper presents the grating lobe reduction in a planar phased array antenna with a rectangular lattice and large element spacing in the order of one wavelength for scan angles up to ±45°. A dual-mode circular microstrip patch antenna is considered as the constitutive element of the phased array, in which two different transverse magnetic modes are exploited simultaneously. The numerical analysis shows that the achieved grating lobe reduction is well below 25 dB for scan angles up to ±45° with large element spacing in the order of one wavelength. 

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4. Orthogonal Filter Frequency Followed by LNA Linearity Tuning for Efficient Instinctual GaN Receiver Front-End

   https://doi.org/10.1109/TCSI.2023.3303778  

   Yang, Jie; Chatterjee, Baibhab; Khater, Mohammad Abu; Thorsell, Mattias; Gunnarsson, Sten E; Sen, Shreyas (November 2023, IEEE Transactions on Circuits and Systems I: Regular Papers)

   This work presents an interference-adaptive Gallium Nitride (GaN) low-noise amplifier (LNA) front-end with orthogonal frequency and linearity tuning for applications in communication base stations, radar and electronic warfare (EW). The system operates between 2–6 GHz and provides a sub 5 ms tuning time for an input power tuning range of 40 dB. The orthogonal tuning consists of two phases: 1. frequency tuning with four tunable bandpass and bandstop filters for interference rejection, 2. linearity tuning with a combination of coarse tuning through look-up table (LUT) and fine-tuning through incremental adaptation to trade off power with linearity. GaN LNA’s linearity can be adjusted between P textsubscript 1dB,IN = -10 and 1.5 dBm with output P textsubscript 1dB up to 25 dBm (11.5 dB range) with the LNA power changing from 500 mW to 2 W (x4 increase). The average LNA power with orthogonal frequency and linearity tuning decreases by 56% as compared with the system operating at the worst-case no tuning condition. Two systems involving commercial filters and custom cavity resonator-based filters were constructed. The filters further increase the system P textsubscript 1dB,IN by the filter rejection of the interference signal. The rest of the controls consume about 10% of the worst-case condition LNA power. 

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5. LaserTRAM-DB: A Time Resolved Analysis Module for the complete reduction of Laser Ablation Inductively Coupled Plasma Mass Spectrometry data

   https://doi.org/10.31223/X5QG95  

   Lubbers, Jordan; Kent, Adam; Russo, Chris (June 2023, Earth ArXiv)

   LaserTRAM-DB is a dashboard for the complete processing pipeline of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) data in complex materials such as geologic samples. As LA-ICP- MS data in geologic samples frequently have multiple phases, inclusions, and other compositional complexities within them that do not represent the material of interest, user interaction is required to filter unwanted signals out of the overall ablation signal. LaserTRAM-DB allows the user to filter which portion of the ablation peak is utilized in calculating concentrations, subsequently allowing for more accurate data to be obtained. Furthermore, it allows for the processing of both individual spot analysis data and a line of spots gathered in rapid succession, reducing the time required for data reduction while preserving spatial definition and still ensuring data quality. 

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