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    Item type:Publication, Access status: with files ,
    Powering mobile sensor nodes in fluidized beds: A non-invasive RF energy harvesting proof-of-concept
    (American Chemical Society (ACS), 2026-10-16) ; ; ; ;
    Real-time monitoring within industrial processing vessels is essential for advancing process analytical technology. Flow-following sensors represent an ideal approach for delivering continuous, in-line data from the process stream. However, deploying these mobile sensors is constrained by the physical barriers of sealed metallic vessels and harsh, battery-hostile environments. To overcome these limitations, a non-invasive, retrofittable wireless power transfer system is presented. The metallic vessel is structurally repurposed into a 5.23 GHz multi-mode microwave cavity resonator by coupling microwave energy through existing standard flanges. Electromagnetic simulations validate that this method generates continuous energy coverage throughout dynamic flow zones, demonstrated using a fluidized bed granulator as an application example. To harness this energy, an omnidirectional antenna and a compact RF-to-DC rectifier prototype were developed. By enabling the continuous operation of autonomous, battery-free mobile sensor nodes, this framework provides a practical, scalable foundation for high-density spatial analytics and data-driven industrial optimization.
    Publicationtype: Journal Article
      12  9
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    Item type:Publication, Access status: with files ,
    Digital predistortion of power amplifiers for quantum computing
    (Institution of Engineering and Technology (IET), 2026-09-01) ; ; ;
    Power amplifiers (PA) are essential for microwave-controlled trapped-ion and semiconductor spin based quantum computers (QC). They adjust the power level of the control signal and therefore the processing time of the QC. Their nonlinearities and memory effects degrade the signal quality and, thus, the fidelity of qubit gate operations. Driving the PA with a significant input power back-off reduces nonlinear effects but is neither power-efficient nor cost-effective. To overcome this limitation, this letter augments the conventional signal generation system applied in QCs by digital predistortion (DPD) to linearize the radio frequency (RF) channel. Numerical analysis of the qubit behavior based on measured representative control signals indicates that DPD improves its fidelity.
    Publicationtype: Journal Article
      15  5
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    Analysis of an integer-N frequency synthesizer for trapped ion quantum computers
    Qubit implementations like trapped ions can be controlled by microwave signals in the gigahertz range, which require a local oscillator (LO) for upconversion. The LO superimposes a static frequency offset and phase noise, both leading to errors in qubit gate operation. Both error terms can be reduced by implementing the LO as an integer-N frequency synthesizer, where a phase-locked loop controls and stabilizes the frequency. An exemplary integer-N frequency synthesizer is realized and its performance for quantum computers is characterized in this work. The qubit fidelity calculated based on phase noise measurement results is above 99.943% for primitive π-gates.
    Publicationtype: Conference Paper
      20
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    Item type:Publication,
    Feedback-receiver-based compensation of nonlinearities in trapped ion qubit gate signaling
    This paper presents an analog microwave frontend designed to downconvert and feed back the control signal for trapped ion qubits, which are frequency-multiplexed by the magnetic gradient induced coupling (MAGIC) principle. Shorter gate durations require a higher excitation signal power, increasing distortion caused by nonlinear components. The proposed feedback receiver serves the purpose of coupling out a portion of the generated qubit control signal to feed it back into the signal generation hardware. This enables closed-loop signal processing techniques to compensate for nonlinearities in signal generation, thus improving the idle fidelity of untargeted qubits. The characterization of a manufactured prototype is performed, followed by an active cancellation of spurious tones based on the downconverted qubit control signal to demonstrate the capability for qubit fidelity improvement.
    Publicationtype: Conference Paper
      32
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    Item type:Publication,
    Design of a microwave frontend for a trapped ion quantum computer
    Unlike classical computers, which represent information as binary '1' and '0', quantum computers use qubits that exist in a superposition of both, enabling parallel computation. This capability allows them to solve special kinds of problems faster than classical computers. To process information, qubits are manipulated by applying energy, such as via a microwave signal, which is provided by a microwave frontend that ensures an appropriate frequency spectrum and power level. This paper defines the key parameters and implements such a frontend for trapped ion quantum computers which follow the magnetic gradient induced coupling (MAGIC) principle. The frontend is manufactured on a printed circuit board and measurements prove its functionality. It achieves an idle gate fidelity of 99.9% (99.99%) at an output power of 6.32 dBm (2.4 dBm).
    Publicationtype: Conference Paper
      80