Department of Electrical and Computer Engineering Faculty Publications

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    Enhancing Urban Vehicular Navigation: Improving Classical Topological Map Matching Through Ray-Casting
    (Copernicus GmbH, 2023-09-06) Ragab, Hany; Givigi, Sidney; Noureldin, Aboelmagd
    Navigation is of paramount importance for land vehicles as it enables efficient and accurate movement from one location to another. Whether it is for personal navigation, commercial transportation, or emergency services, reliable navigation systems play a crucial role in ensuring safety, optimizing routes, and enhancing overall operational efficiency. This paper presents the integration of classical Topological Map Matching (TMM) with the Global Navigation Satellite System (GNSS) and the Inertial Navigation System (INS), addressing the limitations of relying solely on road centerlines. A novel solution is proposed, leveraging the ray-casting algorithm to determine the predicted position's area and employing a two-stage kinematic update process for enhanced positioning accuracy. The solution's efficacy is evaluated through tests conducted on simulated GNSS outages within a road experiment conducted in the City of Toronto, demonstrating substantial improvements compared to the classical TMM approach. Notably, the proposed method achieved a considerable 82.33% reduction in RMS positioning error and a 33.71% improvement in maximum positioning error during the longest GNSS outage. By overcoming the limitations of classical TMM algorithms, this research contributes to the advancement of navigation and tracking systems, with future work focusing on practical implementations and optimization for diverse navigation scenarios.
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    Variable 360° Vector-Sum Phase Shifter With Coarse and Fine Vector Scaling
    (2016-08-08) Mohsenpour, Mohammad-Mahdi; Saavedra, Carlos E.
    A CMOS vector-sum phase shifter covering the full 360° range is presented in this paper. Broadband operational transconductance amplifiers with variable transconductance provide coarse scaling of the quadrature vector amplitudes. Fine scaling of the amplitudes is accomplished using a passive resistive network. Expressions are derived to predict the maximum bit resolution of the phase shifter from the scaling factor of the coarse and fine vector-scaling stages. The phase shifter was designed and fabricated using the standard 130-nm CMOS process and was tested on-wafer over the frequency range of 4.9–5.9 GHz. The phase shifter delivers root mean square (rms) phase and amplitude errors of 1.25° and 0.7 dB, respectively, at the midband frequency of 5.4 GHz. The input and output return losses are both below 17 dB over the band, and the insertion loss is better than 4 dB over the band. The circuit uses an area of 0.303 mm2 excluding bonding pads and draws 28 mW from a 1.2 V supply.
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    Method to Improve the Conversion Gain Flatness of Transformer-Coupled Mixers
    (2016-08-08) Li, Hao
    A 4-10 GHz, on-chip balun based current commutating mixer is proposed. Tunable resistive feedback is used at the transconductance stage for wideband response, and interlaced stacked transformer is adopted for good balance of the balun. Measurement results show that a conversion gain of 13.5 dB, an IIP3 of 4 dBm and a noise figure of 14 dB are achieved with 5.6 mW power consumption under 1.2 V supply. The simulated amplitude and phase imbalance is within 0.9 dB and ±2◦ over the band.
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    A Decade-Bandwidth Low-Noise Mixer RFIC with a Distortion-Canceling Output Amplifier
    (2016-08-08) El-Gabaly, Ahmed M.; Li, Hao; Saavedra, Carlos E.
    This paper presents a 1-10 GHz low-noise downconvert mixer RFIC suitable for wideband receivers. A switched transconductor mixing core is adopted to reduce noise at high frequencies. By adding a series inductor to the RF transconductor, a flat 4-5 dB noise figure (NF) and a high gain of 26.5 dB can be achieved over a broad bandwidth out to 10 GHz. A CMOS output amplifier is also integrated on-chip, employing derivative superposition (DS) for high linearity and an OIP3 of 16.5 dBm. The circuit consumes less than 20 mW of dc power and occupies an active chip area of less than 0.2 mm2.
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    Method to Improve the Linearity of Active Commutating Mixers Using Dynamic Current Injection
    (2016-08-08) Mohsenpour, Mohammad-Mahdi; Saavedra, Carlos E.
    A double balanced (DBM) CMOS mixer providing high linearity is presented in this paper. A cross-coupled pair used in the IF stage of the mixer to dynamically inject current into the to mixer provide a high linearity. The proposed DBM was fabricated using a standard 130-nm CMOS process and was tested on-wafer. The double balanced mixer delivers 10 dB conversion gain, 9.5 dBm IIP3, and input P1dB of -2.4 dBm. RF bandwidth of the proposed mixer is 6 GHz, covering 0.5 GHz to 6.5 GHz with IF bandwidth of 300 MHz. RF to IF and LO to IF isolation are also better than 59 dB in the whole frequency band. The circuit uses an area of 0.015 mm2 excluding bonding pads and draw 4.5mW from a 1.2V supply.