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  • 1.
    Hussain, Muhammad Waqar
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    High-Temperature Radio Circuits in Silicon Carbide Bipolar Technology2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    High-temperature electronics find many niche applications in downhole drilling, aviation, automotive and future exploration of inner planets like Venus and Mercury. Past studies have shown the potential of silicon carbide (SiC) electronics for catering these extreme temperature applications. In particular, analog, digital and mixed-signal integrated circuits, based on in-house SiC bipolar technology, have been shown to operate successfully for temperatures as high as 500 oC. This thesis aims at exploring the potential of in-house SiC bipolar technology for realizing high-temperature radio frequency (RF) circuits.

    To that end, the in-house SiC bipolar junction transistors (BJTs) are first characterized up to 300 oC for RF figures of merit like unity current gain bandwidth and unity power gain bandwidth. The measurement results showed the feasibility of the current batch of SiC BJTs for developing RF circuits operating at low-end of very high frequency (VHF) band. Thereafter, three fundamental blocks of a high-temperature radio receiver, i.e. an intermediate-frequency amplifier, an oscillator and a down-conversion mixer were implemented. Firstly, an intermediate-frequency amplifier has been designed and measurement results demonstrated operation up to 251 oC. The proposed amplifier achieved a gain, input, and output matching of 16 dB, -7.5 dB and -11.2 dB, respectively, at 54.6 MHz and 251 oC. Next, 500 oC operation of an active down-conversion mixer has been exhibited. Measurements have shown that the conversion gain of the proposed mixer is 4.7 dB at 500 oC. Lastly, a negative resistance oscillator has been designed and tested successfully up to 400 oC. It has been shown that at 400 oC, the proposed oscillator delivers an output power of 8.4 dBm into a 50 Ω load.

    In addition to SiC BJTs, the aforementioned circuits also employed spiral inductors implemented on PCBs, commercially available ceramic capacitors and thick-film resistors. Therefore, this thesis presents the evaluation of passives to assess their feasibility for high temperature operation. This work also identifies and addresses several challenges associated with the development flow of high-temperature RF circuits.

  • 2.
    Hussain, Muhammad Waqar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Elahipanah, Hossein
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar. Ascatron AB.
    Rodriguez, Saul
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Malm, B. Gunnar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Rusu, Ana
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Silicon Carbide BJT Oscillator Design Using S-Parameters2018Inngår i: European Conference on Silicon Carbide and Related Materials (ECSCRM), Birmingham September 2-6, 2018., 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Radio frequency (RF) oscillator design typically requires large-signal, high-frequency simulation models for the transistors. The development of such models is generally difficult and time consuming due to a large number of measurements needed for parameter extraction. The situation isfurther aggravated as the parameter extraction process has to be repeated at multiple temperature points in order to design a wide-temperature range oscillator. To circumvent this modelling effort, analternative small-signal, S-parameter based design method can be employed directly without goinginto complex parameter extraction and model fitting process. This method is demonstrated through design and prototyping a 58 MHz, high-temperature (HT) oscillator, based on an in-house 4H-SiC BJT. The BJT at elevated temperature (up to 300 0C) was accessed by on-wafer probing and connectedby RF-cables to the rest of circuit passives, which were kept at room temperature (RT).

  • 3.
    Hussain, Muhammad Waqar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Elahipanah, Hossein
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Rodriguez, Saul
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Malm, B. Gunnar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Rusu, Ana
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Silicon carbide BJT oscillator design using S-parameters2019Inngår i: Silicon Carbide and Related Materials 2018, Trans Tech Publications Ltd , 2019, s. 674-678Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Radio frequency (RF) oscillator design typically requires large-signal, high-frequency simulation models for the transistors. The development of such models is generally difficult and time consuming due to a large number of measurements needed for parameter extraction. The situation is further aggravated as the parameter extraction process has to be repeated at multiple temperature points in order to design a wide-temperature range oscillator. To circumvent this modelling effort, an alternative small-signal, S-parameter based design method can be employed directly without going into complex parameter extraction and model fitting process. This method is demonstrated through design and prototyping a 58 MHz, high-temperature (HT) oscillator, based on an in-house 4H-SiC BJT. The BJT at elevated temperature (up to 300 °C) was accessed by on-wafer probing and connected by RF-cables to the rest of circuit passives, which were kept at room temperature (RT).

  • 4.
    Hussain, Muhammad Waqar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Elahipanah, Hossein
    KTH.
    Schröder, Stephan
    KTH.
    Rodriguez, Saul
    KTH.
    Malm, B. Gunnar
    KTH.
    Östling, Mikael
    KTH.
    Rusu, Ana
    KTH.
    An Intermediate Frequency Amplifier for High-Temperature Applications2018Inngår i: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 65, nr 4, s. 1411-1418Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a two-stage small signal intermediate frequency amplifier for high-temperature communication systems. The proposed amplifier is implemented using in-house silicon carbide bipolar technology. Measurements show that the proposed amplifier can operate from room temperature up to 251 °C. At a center frequency of 54.6 MHz, the amplifier has a gain of 22 dB at room temperature, which decreases gradually to 16 dB at 251 °C. Throughout the measured temperature range, it achieves an input and output return loss of less than-7 and-11 dB, respectively. The amplifier has a 1-dB output compression point of about 1.4 dBm, which remains fairly constant with temperature. Each amplifier stage is biased with a collector current of 10 mA and a base-collector voltage of 3 V. Under the aforementioned biasing, the maximum power dissipation of the amplifier is 221 mW.

  • 5.
    Hussain, Muhammad Waqar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Elahipanah, Hossein
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Schröder, Stephan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Rodriguez, Saul
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Malm, Bengt Gunnar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Östling, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Rusu, Ana
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    An Intermediate Frequency Amplifier for High-Temperature Applications (vol 65, pg 1411, 2018)2019Inngår i: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 66, nr 8, s. 3694-3694Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This correspondence highlights an error in the above-titled paper. The corrected material is presented here.

  • 6.
    Hussain, Muhammad Waqar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Elahipanah, Hossein
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar. Ascatron AB.
    Zumbro, John E.
    University of Arkansas.
    Rodriguez, Saul
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Malm, B. Gunnar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Mantooth, H. Alan
    University of Arkansas.
    Rusu, Ana
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    A SiC BJT-Based Negative Resistance Oscillator for High-Temperature Applications2019Inngår i: IEEE Journal of the Electron Devices Society, ISSN 2168-6734, Vol. 7, nr 1, s. 191-195Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This brief presents a 59.5 MHz negative resistanceoscillator for high-temperature operation. The oscillator employs an in-house 4H-SiC BJT, integrated with the requiredcircuit passives on a low-temperature co-fired ceramic substrate. Measurements show that the oscillator operates from room-temperature up to 400 C. The oscillator delivers an output◦power of 11.2 dBm into a 50 Ω load at 25 C, which decreases to 8.4 dBm at 400 C. The oscillation frequency varies by 3.3% in the entire temperature range. The oscillator is biased witha collector current of 35 mA from a 12 V supply and has amaximum DC power consumption of 431 mW.

  • 7.
    Hussain, Muhammad Waqar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Elahipanah, Hossein
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Zumbro, John E.
    University of Arkansas.
    Schröder, Stephan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Rodriguez, Saul
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Malm, B. Gunnar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Mantooth, H. Alan
    University of Arkansas.
    Rusu, Ana
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    A 500 °C Active Down-Conversion Mixer in Silicon Carbide Bipolar Technology2018Inngår i: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 39, nr 6, s. 855-858Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This letter presents an active down-conversion mixer for high-temperature communication receivers. The mixer is based on an in-house developed 4H-SiC BJT and down-converts a narrow-band RF input signal centered around 59 MHz to an intermediate frequency of 500 kHz. Measurements show that the mixer operates from room temperature up to 500 °C. The conversion gain is 15 dB at 25 °C, which decreases to 4.7 dB at 500 °C. The input 1-dB compression point is 1 dBm at 25 °C and −2.5 dBm at 500 °C. The mixer is biased with a collector current of 10 mA from a 20 V supply and has a maximum DC power consumption of 204 mW. High-temperature reliability evaluation of the mixer shows a conversion gain degradation of 1.4 dB after 3-hours of continuous operation at 500 °C.

  • 8.
    Hussain, Muhammad Waqar
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Rusu, Ana
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Modeling Temperature Dependence of fT in 4H-SiC Bipolar Transistors2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This paper models the temperature dependence of fT in 4H-SiC bipolar devices. The proposed model describes variation of the constituent parameters of fT as a function of temperature. The model assumes complete ionization of dopants in 4H-SiC. However, this assumption hampers the model’s utilityat temperatures below 300◦C. The model was simulated attemperatures between 300◦C and 700◦C and a drop in fT wasobserved. However, measurements are required to prove thecorrectness of the model or lack thereof.

  • 9.
    Rodriguez, S.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Ollmar, S.
    Waqar, M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Rusu, A.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    A Batteryless Sensor ASIC for Implantable Bio-Impedance Applications2015Inngår i: IEEE Transactions on Biomedical Circuits and Systems, ISSN 1932-4545, E-ISSN 1940-9990Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The measurement of the biological tissue’s electrical impedance is an active research field that has attracted a lot of attention during the last decades. Bio-impedances are closely related to a large variety of physiological conditions; therefore, they are useful for diagnosis and monitoring in many medical applications. Measuring living tissues, however, is a challenging task that poses countless technical and practical problems, in particular if the tissues need to be measured under the skin. This paper presents a bio-impedance sensor ASIC targeting a battery-free, miniature size, implantable device, which performs accurate 4-point complex impedance extraction in the frequency range from 2 kHz to 2 MHz. The ASIC is fabricated in 150 nm CMOS, has a size of 1.22 mm × 1.22 mm and consumes 165 μA from a 1.8 V power supply. The ASIC is embedded in a prototype which communicates with, and is powered by an external reader device through inductive coupling. The prototype is validated by measuring the impedances of different combinations of discrete components, measuring the electrochemical impedance of physiological solution, and performing ex vivo measurements on animal organs. The proposed ASIC is able to extract complex impedances with around 1 Ω resolution; therefore enabling accurate wireless tissue measurements.

  • 10. Sarwar, Farah
    et al.
    Iqbal, Shaukat
    Hussain, Muhammad Waqar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Linear and Nonlinear Electrical Models of Neurons for Hopfield Neural Network2016Inngår i: Zeitschrift fur Naturforschung A-A Journal of Physical Sciences, ISSN 0932-0784, E-ISSN 1865-7109, Vol. 71, nr 11, s. 995-1002Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel electrical model of neuron is proposed in this presentation. The suggested neural network model has linear/nonlinear input-output characteristics. This new deterministic model has joint biological properties in excellent agreement with the earlier deterministic neuron model of Hopfield and Tank and to the stochastic neuron model of McCulloch and Pitts. It is an accurate portrayal of differential equation presented by Hopfield and Tank to mimic neurons. Operational amplifiers, resistances, capacitor, and diodes are used to design this system. The presented biological model of neurons remains to be advantageous for simulations. Impulse response is studied and conferred to certify the stability and strength of this innovative model. A simple illustration is mapped to demonstrate the exactness of the intended system. Precisely mapped illustration exhibits 100 % accurate results.

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