Journal Articles

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915

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Author: search.filters.author.Hasan SMRHas files: Yes

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    A 6 GHz Integrated High-Efficiency Class-F−1 Power Amplifier in 65 nm CMOS Achieving 47.8% Peak PAE
    (MDPI (Basel, Switzerland), 2021-10-09) Ali SMA; Hasan SMR; Ebrahimi A
    This paper reports a “single-transistor” Class-F−1 power amplifier (PA) in 65 nm CMOS, which operates at the microwave center frequency of 6 GHz. The PA is loaded with a Class-F−1 harmonic control network, employing a new “parasitic-aware” topology deduced using a novel iterative algorithm. A dual-purpose output matching network is designed, which not only serves the purpose of output impedance matching, but also reinforces the harmonic control of the Class-F−1 harmonic network. This proposed PA yields a peak power-added efficiency (PAE) of 47.8%, which is one of the highest when compared to previously reported integrated microwave/millimeter-wave PAs in CMOS and SiGe technologies. The amplifier shows a saturated output power of 14.4 dBm along with an overall gain of 13.8 dB.
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    On the gm-Boosted Miller-Effect Minimized Inverter-Cascode Transimpedance Amplifier for Sensor Applications
    (IEEE, 2021-10-20) Zhang Y; Hasan SMR; Grujić D
    This paper presents the small-signal operation of a gm-boosted inverter-cascode transimpedance amplifier which has not been reported previously and whose comprehensive analysis is not available in any reported article or text-book. A simplified sequential equivalent-circuit method is employed which eliminates the need for complicated circuit analysis techniques. The analysis shows that the gain and the gain-bandwidth of the gm-boosted inverter-cascode transimpedance-amplifier is enhanced by the gain of the gm-boosting amplifier. This is due to the increased output impedance of the TIA, and, the reduced input-referred miller-effect capacitance through miller-effect trade-off employing the gm-boosting loop. To verify the actual performance improvement achieved, circuit simulation results as well as measured experimental results are also provided.
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    Ultraviolet-C Photoresponsivity Using Fabricated TiO2 Thin Films and Transimpedance-Amplifier-Based Test Setup
    (MDPI (Basel, Switzerland), 2022-11) Cadatal-Raduban M; Pope J; Olejníček J; Kohout M; Harrison JA; Hasan SMR; Torres ML; De Luca AC; Mourka A
    We report on fabricated titanium dioxide (TiO2) thin films along with a transimpedance amplifier (TIA) test setup as a photoconductivity detector (sensor) in the ultraviolet-C (UV-C) wavelength region, particularly at 260 nm. TiO2 thin films deposited on high-resistivity undoped silicon-substrate at thicknesses of 100, 500, and 1000 nm exhibited photoresponsivities of 81.6, 55.6, and 19.6 mA/W, respectively, at 30 V bias voltage. Despite improvements in the crystallinity of the thicker films, the decrease in photocurrent, photoconductivity, photoconductance, and photoresponsivity in thicker films is attributed to an increased number of defects. Varying the thickness of the film can, however, be leveraged to control the wavelength response of the detector. Future development of a chip-based portable UV-C detector using TiO2 thin films will open new opportunities for a wide range of applications.
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    A Process-Based Temperature Compensated On-Chip CMOS VHF VCRO in 130-nm Si-Ge BiCMOS by Implementing an Empirical Control Equation
    (IEEE, 2022-12-14) Hasan SMR; Sin S-W
    This paper presents a low-power CMOS temperature and process compensated 150.9 MHz Very-high-frequency (VHF) voltage-controlled-ring-oscillator (VCRO) for on-chip integration. The design employs a CMOS temperature-sensor and novel feedback control circuitry to generate the internal control-voltage for the VCRO which ensures oscillation in the vicinity of the desired frequency despite variations in temperature. The control circuitry is the implementation of an empirical equation expressing a temperature sensor-voltage into a specific control-voltage for three different process corners using three different switches. The control-voltage calibrates against temperature variation for the specific process-corner in order to maintain the same frequency of oscillation. Simulations shows that the proposed design maintains the oscillator's frequency within 0.39% from -10°C to 90°C. The fabricated chip implemented in 130-nm GF 8HP Si-Ge BiCMOS process, occupies an area of 0.0242-mm2 and consumes 325 μW while operating with a 1 V supply-voltage. The performance was verified through experimental immersion of DUT (device-under-test) in a temperature-controlled water-bath in the range 22.5°C-70°C.