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Superconducting Qubits
Published in David A. Cardwell, David C. Larbalestier, Aleksander I. Braginski, Handbook of Superconductivity, 2022
Britton Plourde, Frank K. Wilhelm-Mauch
The linear oscillators that form the readout and coupling cavities for qubits in cQED are most typically formed either from planar structures on the same substrate as the qubit, or in 3D waveguide cavities machined out of metal blocks. For planar, thin-film cavities, these are commonly fabricated in a coplanar waveguide (CPW) configuration, with a central signal trace plus a gap on either side to regions of ground plane. The CPW geometry and substrate dielectric response determine the wave impedance and velocity; either open- or short-circuit boundary conditions (BCs) at the two ends of the CPW fix the cavity length and hence determine the resonance frequency. Opposite BCs at the two ends lead to a quarter-wavelength fundamental resonance, while BCs of the same type at both ends result in a half-wave fundamental resonance (Göppl et al., 2008).
Integral Equation Solutions
Published in Xing-Chang Wei, Modeling and Design of Electromagnetic Compatibility for High-Speed Printed Circuit Boards and Packaging, 2017
The power–ground plane pair from [11] is shown in Figure 3.16 for the validation. The signal trace includes three parts: left microstrip line, stripline, and right microstrip line. Two through-hole vias are used to connect them. Three ports are defined in Figure 3.16: port 1 is located at an upper position and connected to the up plane and the down plane, ports 2 and 3 are connected to the two ends of the trace, respectively. Port 1 is used to generate the noise between the two planes, and the coupling between port 1 and port 2 is analyzed. In the simulation, the thickness of the trace and planes is 0.01 mm and the dielectric constant of the substrate is 4.6.
Printed Circuit Boards
Published in David A. Weston, Electromagnetic Compatibility, 2017
Reference 2 describes a method of analyzing a microstrip PCB (signal trace above a ground plane) attached to a shielded enclosure. When the results of the prediction are compared to the test results in Ref. 1, scaled to account for the different dimensions of the PCB, the results are extremely close. For example, the radiation from the microstrip is computed at 47.7 dBμV/m and measured at 48.5 dBμV/m, an uncharacteristically high correlation of 0.8 dB. In contrast, one of the computer programs described in Section 11.9 predicts a massive 28 dB higher level of radiation from the same PCB layout as described in Ref. 2.
Near-Perfect Time–Frequency Analysis of Power Quality Disturbances
Published in IETE Journal of Research, 2022
From (1)–(11), it is evident that the idea of NPTFA is to compute phase-shifted STFT of a signal, trace its IF, and finally obtain the STFT coefficients corresponding to IF. For digital computation, it is necessary to simplify the continuous-time expressions. The phase-shifted STFT of a continuous-time signal can be given as: where, symbolizes the phase-shifted STFT, represents the signal, and is the window. If a discrete time signal with samples is considered, then (14) can be discretized as: where, refers to time samples and signifies the frequency bins. As seen from (11), the IF is traced using . Here, will be represented by . From (14), would be obtained as shown in (16).
Open-source concealed EEG data collection for Brain-computer-interfaces - neural observation through OpenBCI amplifiers with around-the-ear cEEGrid electrodes
Published in Brain-Computer Interfaces, 2021
Michael Thomas Knierim, Christoph Berger, Pierluigi Reali
Given that previous research has indicated that the cEEGrid electrodes might be collecting more physiological information than just changes in neural activity, specifically, the electrical activity of the heart [1,18], it was explored how accurately this feature is represented by comparing the heart periods extracted from the EEG recording to those derived from a standard ECG. For this EEG-ECG signal comparison, ECG traces extracted from independent components (IC) of the cEEGrid recordings were first visually compared for their similarity to regular ECG recordings. Figure 10 shows an example of the selected IC for each of the remaining participants together with a regular ECG signal from the same resting phase. From these traces, the presence of the characteristic R wave is visible, particularly in four out of five participants. Interestingly, it has been reported that only for 50 to 60% of participants, this ECG signal trace can be retrieved [1]. Our sample is very small, yet it might indicate that the percentage in the population for which this ECG trace is available in the cEEGrid data could be a bit higher. Nevertheless, from top to bottom, the traces show a reduction of signal-to-noise ratio and increasingly less evident R peaks, reflecting variability in subjects’ physiological characteristics, electrodes adherence to the skin, or small changes in their placement.
Populated power plane for wideband switching noise mitigation using CSRRs
Published in International Journal of Electronics Letters, 2021
Mohammed M. Bait-Suwailam, Akram Alomainy, Omar Ramahi
Figure 4 depicts the CSRRs-power plane with signal trace layer on top, thus comprising a three-layer PCB layout (i.e., two FR-4 substrates, each with a thickness of 0.4 mm). For comparison purpose, an identical transmission line was also considered but referenced to solid power plane. The signal traces were designed to have a characteristic impedance of 50 , with a trace width of 0.77 mm. For SI retrieval, a nonreturn to zero (NRZ) pseudorandom binary sequence 2 N−1 with N = 7 is sent at port 1 over the signal trace line, and the signal is monitored at the output port (port 2). The binary sequence was coded at 1 Gbit/s with 500 mV-peak and nominal rise and fall times of 100 ps. The eye patterns are generated using CST Microwave Studio. Figure 5(a) shows the eye diagram for the CSRRs-power plane board. The maximum eye open (MEO) and maximum eye width (MEW) are two important metrics that are usually used for SI assessment. As shown in Figure 5(a), the SI performance of the CSRRs-populated PCB board shows satisfactory performance with MEO = 550 mV and MEW = 0.980 ns. For comparison, the eye diagram for the solid power plane is also presented as shown in Figure 5(b), with very clear eye opening (MEO = 980 mV and MEW = 1.0 ns.)