LC Passive Wireless Sensor System Based on Two Switches for Detection of Triple Parameters

Abstract

This paper presents the LC-type passive wireless sensing system for the simultaneous and independent detection of triple parameters, featuring three different capacitive sensors controlled by two mechanical switches. The sensor coil was connected with three different capacitors in parallel and two mechanical switches were in series between every two capacitors, which made the whole system have three resonant frequencies. The readout coil was magnetically coupled with the sensor coil to interrogate the sensor wirelessly. The circuit was simulated advanced design system (ADS) software, and the LC sensor system was mathematically analyzed by MATLAB. Results showed that the proposed LC sensing system could test three different capacitive sensors by detecting three different resonant frequencies. The sensitivity of sensors could be determined by the capacitance calculated from the detected resonant frequencies, and the resolution of capacitance was 0.1 PF and 0.2 PF when using the proposed sensor system in practical applications. To validate the proposed scheme, a PCB inductor and three variable capacitors were constructed with two mechanical switches to realize the desired system. Experimental results closely verified the simulation outputs.

Practical Evaluation of Loss Reduction in Isolated Series Resonant Converter with Fixed Frequency Modulation

“…The output waveform of the system is symmetrical and therefore, in the steady state the RMS value can be considered as the RMS value of the current in the half cycle. By employing the equations of stage 2 (i.e., Equations ( 7), ( 11) and ( 12)) for the initial half cycle, the RMS current for the proposed SRC under FFM can be achieved, as indicated in Equation (17).…”

“…There are three terms in the RMS current shown in Equation (17), in which the first term is from stage 1, the second term is from stage 2 and the third term is from stage 3. The conduction losses in the proposed SRC based on FFM is nearly the same as the conventional LC-DAB topology, as shown in Figure 5.…”

“…However, the power density and performance deteriorated due to the linearly increasing nature of the inductor current. Resonant tanks such as L, LC, LLC, and CLLC are introduced in traditional DAB topology to improve the overall performance [16,17]. L-tank is explored for single-phase and threephase converters in [18], reducing energy losses.…”

A Passive Wireless Smart Washer for Locking Force Monitoring on the Orthopedic Pedicle Screw

“…LC (inductor and capacitance) sensors could be passive and wireless, and many design improvement schemes were proposed [20][21][22][23][24][25][26][27][28][29][30]. Some of them were proposed for wireless sensing in harsh environment, including sensing pH in chemical environment [20], working at high-temperature environment [21][22][23].…”

Effects of Environmental and Operational Conditions on Structural Health Monitoring and Non-Destructive Testing: A Systematic Review

“…The configuration of active and passive SHM systems is illustrated in Figure 1. SHM methods can be implemented utilizing different types of sensors, such as accelerometers [61,62], vibrating wire transducers [63], fiber optic sensors [64], linear variable differential transformer (LVDT) [65], strain gauges [66], load cells [67], temperature sensors [68], acoustic emission sensors [69], an inclinometer (slope indicator) [70], a tiltmeter [71], antenna sensors [72], Resonant(LC)/Resistor-Capacitor(RC) circuit sensors [73,74], and Micro-Electro-Mechanical System sensors (MEMS) [75]. MEMS and LC/RC circuit sensors can be employed in active and passive SHM approaches.…”