A push-push transformer-based voltage-controlled oscillator (VCO) is proposed and analyzed to achieve high efficiency and a wide tuning range at sub-terahertz (THz) frequencies.Analyses show that the coupling factor of the transformer to obtain high output power has to be carefully chosen by consideration of gate-to-drain voltage gain as well as matching impedances seen from the drain and to the gate of a VCO transistor at the 2nd harmonic frequency . Analysis also shows that the transformer-based resonator allows a wide tuning range. In addition, it has been shown that the introduction of a parallel inductor to a varactor leads to high and low phase noise. The proposed 239 GHz VCO with a 65 nm CMOS process demonstrates the high efficiency of 1.45%, the of 4.8 dBm, and the wide tuning range of 12.5% with a supply voltage of 1.2 V.Index Terms-High efficiency, J-band, millimeter wave, push-push oscillator, terahertz, transformer, voltage-controlled oscillator (VCO), wide tuning range.

This paper presents an evaluation method for a 1 mm coaxial calibration kit that can be used from DC to 110 GHz. The analytical model for the calibration kit was revisited and verified by comparing it with the electromagnetic High-Frequency Structure Simulator (HFSS). We also proposed a method to measure or appropriately estimate the physical parameters of the analytic model. This approach calculates the uncertainty based on the physical parameters, so that the uncertainty can be appropriately propagated to different measured quantities based on the covariance between all frequencies, including the real and imaginary parts. To verify the proposed method, a commercially available 1 mm calibration kit was evaluated, and the impedance of a device under test was measured using the evaluated kit. We compared the measured results with those of the National Institute of Standards and Technology (NIST) and confirmed that they agreed well with each other within the uncertainty. Additionally, the multiple reflections caused by the impedance mismatch between the signal source and the instrument was corrected, and its calibrated uncertainty was obtained in the time domain. Thus, the uncertainty of the impedance measurement in the frequency domain was properly propagated to the time domain.

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Pharmacotherapy of vascular anomalies has limited efficacy and potentially limiting toxicity. Targeted nanoparticle (NP) drug delivery systems have the potential to accumulate within tissues where the vasculature is impaired, potentially leading to high drug levels (increased efficacy) in the diseased tissue and less in off-target sites (less toxicity). Here, we investigate whether NPs can be used to enhance drug delivery to bioengineered human vascular networks (hVNs) that are a model of human vascular anomalies. We demonstrate that intravenously injected phototargeted NPs enhanced accumulation of NPs and the drug within hVNs. With phototargeting we demonstrate 17 times more NP accumulation within hVNs than was detected in hVNs without phototargeting. With phototargeting there was 10-fold more NP accumulation within hVNs than in any other organ. Phototargeting resulted in a 6-fold increase in drug accumulation (doxorubicin) within hVNs in comparison to animals injected with the free drug. Nanoparticulate approaches have the potential to markedly improve drug delivery to vascular anomalies.

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We propose a new residual model to analyze the uncertainty of scattering parameters (Sparameters) calibrated by an electronic calibration unit (ECU). Residual errors are usually estimated from the observed ripple after connecting a load or a short at the end of an airline. Therefore, this ripple method can only be used in a frequency range where the airline loss was not large. We, however, obtained the residual error from the uncertainty of the calibration kit using a simple numerical approach. As a result, we can determine the correlations between real/imaginary and magnitude/phase uncertainties. The proposed residual model showed the same results as the VNA error model. We also added a new error term to account for the effect of temperature-dependent drift of the ECU. In addition, we analytically derived the sensitivity coefficients for a 2-port DUT based on the proposed residual model. The proposed residual model will be helpful for the uncertainty analysis of S-parameters calibrated using the ECU.

This paper proposes non-contact heartbeat sensor using LC oscillator for personal healthcare. The signals from chest and wrist are measured using LC oscillator and electrodes. The proposed sensor can detect human heartbeat signal without direct contact to skin and is readily a portable heartbeat monitoring sensor. The capacitive and inductive electrodes are addressed, which are key elements of the sensor circuit.

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