China
Africa
Explore chapters and articles related to this topic
AC Circuit Analysis
Published in Bogdan M. Wilamowski, J. David Irwin, Fundamentals of Industrial Electronics, 2018
Carlotta A. Berry, Deborah J. Walter
Sometimes there are restrictions on the load and it is not possible to set this value to the conjugate of the Thevenin equivalent impedance. One solution is to design the load impedance magnitude to equal the magnitude of the Thevenin impedance, |ZL| = |Zth|. Alternately, if there are restrictions on the values of the resistance or reactance, it is possible to design XL as close as possible to Xth and then adjust RL as close as possible to Rth2+(XL+XTh)2. Lastly, when the load impedance is set and cannot be adjusted at all, an ideal transformer can be used to design for impedance matching. Impedance matching is the process of designing a system to match the source and load impedance in order to maximize the average power delivered to the load.
Signal Simulators and Emulators
Published in Felix Alberto Farret, Marcelo Godoy Simões, Danilo Iglesias Brandão, Electronic Instrumentation for Distributed Generation and Power Processes, 2017
Felix Alberto Farret, Marcelo Godoy Simões, Danilo Iglesias Brandão
The attenuator can reduce the signal amplitude to a known value through a previous calibration to match the source impedance or load. Impedance matching is important because if the load impedance is less than that of the source output, then there is an overloading on the source. Conversely, if the load impedance is greater than the source output impedance, there will be an underused power source. Regardless of the attenuation level, the output signal of the attenuator is based on a fixed impedance. The power reduction of the input signal after the attenuator is constant: AdB=10logPPref=20logVVref=20logIIref
Dosimetry in Electroporation-Based Technologies and Treatments
Published in Marko Markov, Dosimetry in Bioelectromagnetics, 2017
Eva Pirc, Matej Reberšek, Damijan Miklavčič
The most complicated of all are nanosecond electroporation systems. They usually consist of nanosecond pulse generator, transmission line or delivery system, and electroporation chamber/electrodes (Pakhomov et al., 2009; Ibey et al., 2010; Batista Napotnik et al., 2016). When using nanosecond pulses, it should always be taken into account that pulses reflect on impedance change and lose power in the transmission line. If the impedance matching is not guaranteed, reflections are present and load dependent. When load impedance is higher, reflections are positive and add to amplitude that would be present on a matched load. In case of lower load impedance, amplitude on the load will be lower. Pulses can become bipolar and cancelation effect can occur. Nanosecond pulses travel approximately 20 cm/ns in coaxial cable (Batista Napotnik et al., 2016).
Application of Behavioral Psychology in Clothing Design from The Perspective of Big Data
Published in Applied Artificial Intelligence, 2023
It can be seen that to improve the common mode rejection capability, We can increase differential voltage gain or decrease common mode voltage gain to increase or decrease the CMRR, which is the ratio of differential voltage gain to common mode voltage gain. Emitter resistance RE should be raised to increase CMRR. The CMRR’s value is frequently influenced by signal frequency. Where, the closed-loop gain, resistance matching accuracy, and of the amplifier circuit must be considered, that is, the multi-op-amp differential amplifier circuit of the following parts should be used. Designing source and load impedances for resistance matching reduces signal reflection or increases power transfer. A circuit’s mismatched resistance will cause a reflection of the signal back to its source. The power transmitted downstream to a load is lessened when a signal reflects. Impedance matching serves the twin purpose of minimizing reflections while facilitating power transmission into a load.
X-Band Multilayer Stacked Microstrip Antenna Using Novel Electromagnetic Band-Gap Structures
Published in IETE Journal of Research, 2023
Mohit Gaharwar, D. C. Dhubkarya
Gain, impedance bandwidth (S11), and radiation characteristics are the essential parameters for any antenna. The ANSYS HFSS was used in this study to enhance the electromagnetic properties of the antenna. First, basic rectangular microstrip was designed utilizing equations (1) to (4). All materials were assigned like FR-4 epoxy for the dielectric substrate and perfect electric conductor (PEC) boundary conditions to the metallic patches. To mimic the SMA connector to microstrip inset feed, wave port excitation of 1 mW in HFSS was selected. Free boundary region (radiation box) was assigned that ensures antenna’s far-field distance to avoid computational complexity. The input reflection coefficient describes the impedance matching between the input microwave source to the antenna such that maximum power can transfer from the source to the antenna. For minimizing the impedance mismatch, it is necessary to get S11 (dB) as low as possible at the resonant frequency. It can also be observed from the smith chart. The input reflection coefficient and gain of the basic rectangular patch were obtained (as shown in Figure 1) and listed in Table 2 for completeness.
Enhancement of output power level of RF energy harvesting circuit using Wilkinson power combiner
Published in International Journal of Electronics Letters, 2023
In this proposed design, different small-size antennas (Makhdoomi, 2018) like spiral, patch, printed antennas are applicable. Multiband antennas are more useful to capture RF signals properly. A proper impedance is required for delivering maximum power to load. Many antennas (Ansarizadeh & Ghorbani, 2008; Kumar et al., 2015) widely used a 50 Ω impedance line which is very popular. An impedance matching network can be made using an L-C circuit. Performance of this impedance matching network can be significantly improved using the inductor along with the capacitor at integrated circuit level design, but fabrication of inductor at high frequencies is difficult compared to capacitors. However, a tunable capacitor is capable of achieving proper impedance in the antenna matching network. The antenna can be tuned to its resonant frequency. The operating frequency can be calculated by the following formula as given in Equation 1.