Unified and non-ideal switch model for analysis of switching circuits

Purpose This paper aims to propose a new unified and non-ideal switch model for analysis of switching circuits. Design/methodology/approach The model has a single unified structure that includes all possible states (on, off) of the switches. The analysis with the proposed switch model requires only one topology and uses the single system equation regardless of states of switches. Moreover, to improve accuracy, the model contains the on-state resistance and capacitive effect of switches. The system equations and the states of switches are updated by control variables, used in the model. Findings There are no restrictions on circuit topology and switch connections. Switches can be internally and externally controlled. The non-ideal nature of the model allows the switch to be modeled more realistically and eliminates the drawbacks of the ideal switch concept. After modeling with the proposed switch model, a linear circuit is obtained. Two examples related to switching circuits are included into the study. The results confirm the accuracy of the model. Originality/value This paper contributes a different switch model for analysis of switching converters to the literature. The main advantage of the model is that it has a unified and non-ideal property. With the proposed switch model, the transient events, like voltage spikes and high-frequency noises, caused by inductor and capacitor elements at switching instants can be observed properly.

A Multi Polarization Square Patch Antenna with a Reconfigurable Feeding Network

<p>Rotation of polarization is the one of problem in communication with linear polarization. In fact, it can reduce the received signal strength down to -20 dB in some cases. Circular polarization is one the accessible approaches for sorting this problem due to it can be immune against polarization rotation. In this paper, proposed antenna can perform in linear and circular polarization which can be switched according to the condition of signal which is being transmitted. Consequently, environmental disruptions could not decline the quality of communication. 1) The proposed antenna is categorized in reconfigurable antennas which have different methods for implementation. First of all, the proposed antenna is a multi-polarization reconfigurable antenna that can radiate circular polarization and linear polarization on the same structure at a specific frequency. Moreover, a simple feeding network for this antenna is implemented. This antenna utilizes common power dividers for feeding the square patch. Finally, switching circuits which are used for changing polarization in this antenna are by far simple than that of existing works.</p>

A Multi Polarization Square Patch Antenna with a Reconfigurable Feeding Network

<p>Rotation of polarization is the one of problem in communication with linear polarization. In fact, it can reduce the received signal strength down to -20 dB in some cases. Circular polarization is one the accessible approaches for sorting this problem due to it can be immune against polarization rotation. In this paper, proposed antenna can perform in linear and circular polarization which can be switched according to the condition of signal which is being transmitted. Consequently, environmental disruptions could not decline the quality of communication. 1) The proposed antenna is categorized in reconfigurable antennas which have different methods for implementation. First of all, the proposed antenna is a multi-polarization reconfigurable antenna that can radiate circular polarization and linear polarization on the same structure at a specific frequency. Moreover, a simple feeding network for this antenna is implemented. This antenna utilizes common power dividers for feeding the square patch. Finally, switching circuits which are used for changing polarization in this antenna are by far simple than that of existing works.</p>

Digital Potentiometers and Digital-to-Analog Converters in Tasks for Tuning Of Active RC-Filters

The most popular schemes of digital potentiometers (DP) and digital-to-analog converters (DAC) are considered. DP and DAC use how elements of parameter adjustment of active RC-filters. The circuits of the DAC on the Kelvin-Varley divider, the Kelvin divider based on the R-2R matrix, and the architecture of the DAC with a segmented circuit are shown. The internal structure of DP an Analog Devices and Intersil company is shown, and also the DP switching circuits in a tunable low-pass filter and a band-pass filter, a programmable inverting amplifier and a voltage regulator are presented.

Acoustic Remote Control of Bacterial Immunotherapy

Rapid advances in synthetic biology are driving the development of genetically engineered microbes as therapeutic agents for a multitude of human diseases, including cancer. In particular, the immunosuppressive microenvironment of solid tumors creates a favorable niche for systemically administered bacteria to engraft in the tumor and release therapeutic payloads. However, such payloads can be harmful if released in healthy tissues where the bacteria also engraft in smaller numbers. To address this limitation, we engineer therapeutic bacteria to be controlled by focused ultrasound, a form of energy that can be applied noninvasively to specific anatomical sites such as solid tumors. This control is provided by a temperature-actuated genetic state switch that produces lasting therapeutic output in response to briefly applied focused ultrasound hyperthermia. Using a combination of rational design and high-throughput screening we optimized the switching circuits of engineered cells and connected their activity to the release of immune checkpoint inhibitors. In a clinically relevant cancer model, ultrasound-activated therapeutic microbes successfully turned on in situ and induced a marked suppression of tumor growth. This technology provides a critical tool for the spatiotemporal targeting of potent bacterial therapeutics in a variety of biological and clinical scenarios.

An Improved Transient Search Optimization with Neighborhood Dimensional Learning for Global Optimization Problems

The transient search algorithm (TSO) is a new physics-based metaheuristic algorithm that simulates the transient behavior of switching circuits, such as inductors and capacitors, but the algorithm suffers from slow convergence and has a poor ability to circumvent local optima when solving high-dimensional complex problems. To address these drawbacks, an improved transient search algorithm (ITSO) is proposed. Three strategies are introduced to the TSO. First, a chaotic opposition learning strategy is used to generate high-quality initial populations; second, an adaptive inertia weighting strategy is used to improve the exploration ability, exploitation ability, and convergence speed; finally, a neighborhood dimensional learning strategy is used to maintain population diversity with each iteration of merit seeking. The Friedman test and Wilcoxon’s rank sum test were also used by comparing the experiments with recently popular algorithms on 18 benchmark test functions of various types. Statistical results, nonparametric sign tests, and convergence curves all indicate that ITSO develops, explores, and converges significantly better than other popular algorithms, and is a promising intelligent optimization algorithm for applications.