The threshold voltage of the MOS transistor is a very important parameter used in all circuit simulation programs. The aim of this paper is to compare several largely applied threshold voltage extraction methods used both for long channel and short channel MOSFETs. This methods use either the linear operation region or the saturation operation region of the transistors. The new derivative extraction method proposed in this paper doesn't depend on the operation region for long channel devices and gives comparable results for short channel devices. It is a very simple and accurate extraction method. The experimental data used in the paper were measured using a HP4155B system. The mathematical calculation and the threshold voltage extraction are performed using MATHCAD designed programs.

Neurotransmitters are an important category of substances used inside the nervous system, whose detection with biosensors has been seriously addressed in the last decades. Dopamine, a neurotransmitter from the catecholamine family, was recently discovered to have implications for cardiac arrest or muscle contractions. In addition to having many other neuro-psychiatric implications, dopamine can be detected in blood, urine, and sweat. This review highlights the importance of biosensors as influential tools for dopamine recognition. The first part of this article is related to an introduction to biosensors for neurotransmitters, with a focus on dopamine. The regular methods in their detection are expensive and require high expertise personnel. A major direction of evolution of these biosensors has expanded with the integration of active biological materials suitable for molecular recognition near electronic devices. Secondly, for dopamine in particular, the miniaturized biosensors offer excellent sensitivity and specificity and offer cheaper detection than conventional spectrometry, while their linear detection ranges from the last years fall exactly on the clinical intervals. Thirdly, the applications of novel nanomaterials and biomaterials to these biosensors are discussed. Older generations, metabolism-based or enzymatic biosensors, could not detect concentrations below the micro-molar range. But new generations of biosensors combine aptamer receptors and organic electrochemical transistors, OECTs, as transducers. They have pushed the detection limit to the pico-molar and even femto-molar ranges, which fully correspond to the usual ranges of clinical detection of human dopamine in body humors that cover 0.1 ÷ 10 nM. In addition, if ten years ago the use of natural dopamine receptors on cell membranes seemed impossible for biosensors, the actual technology allows co-integrate transistors and vesicles with natural receptors of dopamine, like G protein-coupled receptors. The technology is still complicated, but the uni-molecular detection selectivity is promising.

Microstrip patch antennas have been used in many applications since their appearance. Despite their great promise, their narrow bandwidth and the loss at high-frequency bands have limited their usage in medical applications. This work proposes a developed low-cost microstrip patch antenna suitable for microwave imaging (MWI) applications within the wideband frequency range. The proposed antenna is loaded with an artificial magnetic conductor (AMC) to improve the antenna performance. The simulated results obtained using computer simulation technology (CST) indicate that the presence of the AMC has improved the frequency selectivity of the antenna at 8.6 GHz with a peak realized gain of 9.90443 dBi and 10.61 dBi for simulated and measured results, respectively. The proposed microstrip antenna has been fabricated to validate the simulated results, and its performance is tested experimentally. Additionally, the fidelity factor of face-to-face (FtF) and side-by-side (SbS) scenarios have been presented. The breast phantom models with a tumor and the antenna operating as a transceiver have been numerically simulated for the application of cancer tumor cell detection. The work will have a significant impact on the design of electromagnetic biosensors.

This paper presents new work regimes accompanied by specific conduction models of an SOI nanotransistor with a vacuum cavity. The tunneling mechanisms are separately explored to find out the dominant mechanism. Afterward, the simulations show for the first time two firms on and off states under the gate command. Strong and weak tunneling regimes are emphasized. For the first time, a quasi-saturation region of the I_D-VDS curves is obtained for V_DS > 6 V. Different device structures are compared. The best configuration has the swing of 290 mV/decade, threshold voltage of -0.5 V and maximum I_ON/I_OFF ratio of 10¹⁰, which is a real gain among the vacuum transistors. Some applications as vacuum diode, switch under the gate command or action as parasitic device are emphasized.

This paper presents for the first time a new configuration of the nothing on insulator (NOI) structure: a vacuum NOI-triode. The main novelty of the new structure consists in the gate that is now part of the vacuum region as in conventional triodes. Each NOI-triode is introduced by a technological plan, followed by the concept validation and characteristics analysis. On the other hand, these NOI-triodes evolve from the NOI-transistor configuration. Consequently, some specific parameters to transistors are improved and permanently compared to some fabricated vacuum nano-transistors that are proposed in literature. For instance, the sub-threshold swing is suddenly decreased from 0.65...4 V/dec to 0.090 V/dec. A low swing is responsible to a high cutoff frequency. The paid price for the NOI-triode is a non-null gate current. To preserve the gained advantages and to keep as low as possible the IGate/IAnode ratio, a special work regime must be selected. This paper devotes a large static and dynamic analysis to find the convenient work regime and possible technological solutions. The drive voltages can be decreased to 1 V, ION current of micro-amperes and excellent IOFF current of atto-amperes. The internal capacitances of 0.9 aF recommend the NOI-triodes to 0.35 ... 4 THz working regime.