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This paper presents a novel compact wideband quadruple-mode bandpass filter (BPF) with four resonant modes and five transmission zeros (TZs). Two T-shaped stepped impedance stub loaded resonators are coupled in parallel to the input and output feed lines to form the entire BPF. To provide a wideband and outstanding rejection in upper stopband, the two TZs are introduced by the stepped impedance stub as well as the designed coupling capacitor, and the two inherent TZs produced by the coupling between the resonators and feed lines are used and carefully tuned. The proposed BPF is fabricated in 65 nm CMOS technology with a core area of 0.072 mm2 (7.1×10-3 λ02). The measurement results show that the 3-dB bandwidth is 24.2 GHz at the center frequency of 94 GHz as well as the minimum insertion loss is 4.6 dB. Meanwhile, the stopband extends to 170 GHz with a stopband rejection above 25 dB.

High frequency (HF) welding of polymer materials is increasingly used in modern manufacturing processes. The literature on HF welding process parameters was reviewed and it was found that 3–5 basic welding parameters were considered, which is insufficient for the scientific study of HF welding of polymeric materials. This article presents the mathematical expressions for the evaluation combining 17 influential parameters. For the first time, the specific and latent heat of the welded polymer material were used. The breaking forces of welds made by RF welding are investigated by varying the anode current, the coupling capacitor, and the exposure time of the HF electromagnetic fields. It was found that the amount of HF energy supplied depends on the breaking forces of the weld. A characteristic inflection point was also observed in the graph of the dependence of the breaking forces on the percentage of the coupling capacitor and the anode current. During elongation, it was observed that the weld is separated by peeling before the inflection point and breaks after the inflection point by tearing at the extruded edges of the weld. If the HF energy is applied to the weld for too long, there will be excessive melting of the material in the weld, thinning of the weld, unfavourable appearance of the extruded edges and electrical breakdown, and a drastic drop in the breaking force. [ABSTRACT FROM AUTHOR]

RELEVANCE. Among the various methods for assessing the technical condition of power equipment, vibration diagnostics occupies an important place. Therefore, improving the quality of hardware for vibration diagnostics is currently extremely important. THE PURPOSE. To develop a vibration sensor with a new principle of operation for systems of technical vibration diagnostics of power equipment, as well as to theoretically substantiate the performance of the proposed sensor. METHODS. When solving the set goal, the main provisions of the theory of vibration diagnostics were applied. RESULTS. A design of the vibration acceleration sensor has been developed, the peculiarity of which is that it is excited by means of constructive coupling capacitors, the first electrode of which is made in the form of a thin-walled metal split cylinder, the role of the second electrodes is performed by the lower row of the winding of each measuring coil, and the function of the inertial element is performed by a screen made in the form of a metal ring fixed on a suspension in the form of a membrane. Based on the electrical equivalent circuit of the sensor, a theoretical substantiation of its operability and efficiency was made. Variants of circuit solutions for the primary and secondary measuring transducers of the measuring device for vibration diagnostics systems have been developed. The primary measuring transducer contains directly a vibration displacement sensor, a sinusoidal voltage source, an input differential measuring amplifier and an analog filter containing a narrow-band filter, a broadband amplifier and a buffer amplifier. The secondary measuring transducer contains a quadrature detector of information signals, an output buffer amplifier and a quadrature reference voltage driver. A block diagram of the hardware solution for the vibration acceleration registration system is also proposed. CONCLUSION. The developed sensor has improved output characteristics and can be used not only for vibration control of power equipment, but also for measuring mechanical vibrations in technical diagnostic systems of various other machines and mechanisms, as well as for tasks of spectral seismic exploration.

There is currently a growing interest in replacing the internal combustion engine with electric motors in transportation applications. However, there are different problems related to electric motors for this application. One of them is the oversizing of the energy decoupling system since to ensure that the decoupling capacitor can store the power fluctuations, the capacitance required by the system is usually oversized. This leads to preference for the use of capacitors with construction technologies that have a lower lifetime than the remaining elements of the propulsion system, directly affecting the reliability of the system. In this article, the energy flow handled by the decoupling capacitor is analyzed considering the critical case of operation of an induction motor to minimize the capacitance required by the propulsion system; emphasizing the conditions that generate a higher energy return, from the motor mode of the electric machine to the decoupling capacitor. From the energy analysis, an equation for the capacitor calculation is obtained, involving proportionality factors that relate to the different operating powers, reducing up to 62.2% of the capacitance value required by the decoupling system, under conditions of maximum energy return in motor mode, compared to existing equations in the literature. [ABSTRACT FROM AUTHOR]

Frequency Modulation (FM) transmitter is a small electronic gadget that has a wire (aerial), produces electromagnetic radio waves, and is capable of transmitting energy through space. It generates radio frequency signals that can be received by a well-designed antenna. At the point where signal reception occurs, the radio waves get energized by a rotating current in the receiving wire. It is therefore, a complex gadget considered to be a high voltage energy system. Its design is complex and thus demands critical maintenance procedures which are costly. In Kenya, there is rapidly growing demand for the use of FM transmitters both among individuals and institutions. This work is carried to design, construct and implement an FM transmitter that is cheaper to buy, easy to maintain and expected to be equally efficient when in operation. An FM transmitter was designed and constructed using transistors, resistors, coils, capacitors and microphone. It was mounted on testing a symbolic bed assumed to be of a patient (at Coast Level Five Hospital), who figuratively required the attention of medical personnel (doctor/nurse/caretaker). It was connected to 12V DC power source and tested. The results revealed that a locally designed FM transmitter that operates on low power can be designed to have an appreciable range of signal transmission. It is recommended that further investigations be carried out on the signal coupling circuit so as to improve the range of transmission further. [ABSTRACT FROM AUTHOR]

The authors review the techniques applied to diagnose oil aging. Further, the authors put forward a new diagnostic method. It stipulates for an additional high-frequency measuring loop formed in an operating transformer. This dielcometric measuring capacitor cell includes a stray capacitance generated by the transformer winding and core. The monitoring of the dependence between the physico–technological oil parameters and the measuring cell capacity is fundamental for the procedures for determining the composition and properties of the transformer oil filling this cell. High-frequency low-voltage is the output signal. To prevent the cross-impact of low-frequency high-voltage and high-frequency low-voltage circuits, the pilot high-frequency low-voltage is excited by a special coupling capacitor; the output to the power feeder is conducted through an appropriate low-frequency choke, where the measuring capacitor cell does not disturb the normal transformer operation. The key physical processes used for the monitoring are analyzed and described in detail. The authors develop an algorithm to compute the current resistances of both the transformer oil and its impurities. The transformer state is estimated by comparing the parameters specified with preset permissible limits. A structure flowchart based on two synchronous quadrature detectors is proposed for a high-frequency measuring loop. The monitoring system considered allows for determining the following insulating oil properties by using the algorithm for processing the recorded data: moisture content; dielectric losses due to the accumulation of aging products in the oil and its pollution; and the content of dissolved gases in the oil. The monitoring system operability and efficiency are confirmed by appropriate experimental studies. The experiments are conducted using a TM-25-6/0.4 oil-filled transformer with a capacity of 25 kVA in a steady-state operating mode at a load current of 25 A. It is found that the proposed control system allows for identifying a critical defect of increased moisture content in the oil with no more than 10% error, and a sensitivity threshold in the order of tenths of ppm. [ABSTRACT FROM AUTHOR]

There is currently a growing interest in replacing the internal combustion engine with electric motors in transportation applications. However, there are different problems related to electric motors for this application. One of them is the oversizing of the energy decoupling system since to ensure that the decoupling capacitor can store the power fluctuations, the capacitance required by the system is usually oversized. This leads to preference for the use of capacitors with construction technologies that have a lower lifetime than the remaining elements of the propulsion system, directly affecting the reliability of the system. In this article, the energy flow handled by the decoupling capacitor is analyzed considering the critical case of operation of an induction motor to minimize the capacitance required by the propulsion system; emphasizing the conditions that generate a higher energy return, from the motor mode of the electric machine to the decoupling capacitor. From the energy analysis, an equation for the capacitor calculation is obtained, involving proportionality factors that relate to the different operating powers, reducing up to 62.2% of the capacitance value required by the decoupling system, under conditions of maximum energy return in motor mode, compared to existing equations in the literature.

Oil-filled high-voltage capacitors are used in high-frequency electrical communication systems, the reliability of which is highly demanding. The article is devoted to the improvement of procedures for diagnosing an oil-filled high-voltage coupling capacitor by using methods of gas chromatographic determination of the content of dissolved diagnostic gases in mineral condenser oils. The aim of the work is to increase the reliability of the technical diagnostics results of electric capacitor communication type SMA-166V3- 14UHL1 to monitor its technical condition, determine the location and causes of failure, predict technical condition and clarify the possibility of maintenance and repair. The following studies were performed: electrical characteristics and thermal field characteristics of the communication capacitor; properties of condenser oil after disassembly of the condenser. The following parameters are determined: for the coupling capacitor - the tangent of the dielectric loss angle, electric capacitance and its changes, electrical resistance; for condenser oil - electric breakdown voltage, dielectric loss tangent, flash point in a closed crucible, density, moisture content, acid number, presence of mechanical impurities, hydrogen solubility, dissolved diagnostic gases content, antioxidant additive and furan compounds. The obtained results allow to increase the reliability of the results of diagnosing the technical condition of oil-filled electric capacitors in connection with the use of traditional and additional methods of diagnosing high-voltage electrical equipment filled with mineral oils. [ABSTRACT FROM AUTHOR]

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The authors review the techniques applied to diagnose oil aging. Further, the authors put forward a new diagnostic method. It stipulates for an additional high-frequency measuring loop formed in an operating transformer. This dielcometric measuring capacitor cell includes a stray capacitance generated by the transformer winding and core. The monitoring of the dependence between the physico–technological oil parameters and the measuring cell capacity is fundamental for the procedures for determining the composition and properties of the transformer oil filling this cell. High-frequency low-voltage is the output signal. To prevent the cross-impact of low-frequency high-voltage and high-frequency low-voltage circuits, the pilot high-frequency low-voltage is excited by a special coupling capacitor; the output to the power feeder is conducted through an appropriate low-frequency choke, where the measuring capacitor cell does not disturb the normal transformer operation. The key physical processes used for the monitoring are analyzed and described in detail. The authors develop an algorithm to compute the current resistances of both the transformer oil and its impurities. The transformer state is estimated by comparing the parameters specified with preset permissible limits. A structure flowchart based on two synchronous quadrature detectors is proposed for a high-frequency measuring loop. The monitoring system considered allows for determining the following insulating oil properties by using the algorithm for processing the recorded data: moisture content; dielectric losses due to the accumulation of aging products in the oil and its pollution; and the content of dissolved gases in the oil. The monitoring system operability and efficiency are confirmed by appropriate experimental studies. The experiments are conducted using a TM-25-6/0.4 oil-filled transformer with a capacity of 25 kVA in a steady-state operating mode at a load current of 25 A. It is found that the proposed control system allows for identifying a critical defect of increased moisture content in the oil with no more than 10% error, and a sensitivity threshold in the order of tenths of ppm.

Important technological advances in the last decades paved the way for a great success story for electrically stimulating medical implants, including cochlear implants or implants for deep brain stimulation. However, there are still many challenges in reducing side effects and improving functionality and comfort for the patient. Two of the main challenges are the wish for smaller implants on one hand, and the demand for more stimulation channels on the other hand. But these two aims lead to a conflict of interests. This paper presents a novel design for an electrical feedthrough, the so called capacitive feedthrough, which allows both reducing the size and increasing the number of included channels. Capacitive feedthroughs include the functionality of a coupling capacitor and an electrical feedthrough within one and the same structure. The paper also discusses the progress and the challenges of the first produced test structures. The concept bears a high potential in improving current feedthrough technology, and could be applied for all kinds of electrical medical implants.

Important technological advances in the last decades paved the road to a great success story for electrically stimulating medical implants, including cochlear implants or implants for deep brain stimulation. However, there are still many challenges in reducing side effects and improving functionality and comfort for the patient. Two of the main challenges are the wish for smaller implants on one hand, and the demand for more stimulation channels on the other hand. But these two aims lead to a conflict of interests. This paper presents a novel design for an electrical feedthrough, the so called capacitive feedthrough, which allows both reducing the size, and increasing the number of included channels. Capacitive feedthroughs combine the functionality of a coupling capacitor and an electrical feedthrough within one and the same structure. The paper also discusses the progress and the challenges of the first produced demonstrators. The concept bears a high potential in improving current feedthrough technology, and could be applied on all kinds of electrical medical implants, even if its implementation might be challenging. [ABSTRACT FROM AUTHOR]

This paper proposes a new interleaved buck converter (IBC) having low switching losses and improved step-down conversion ratio, which is suitable for the applications where the input voltage is high and the operating duty is below 50%. It is similar to the conventional IBC, but two active switches are connected in series and a coupling capacitor is employed in the power path, such as Cuk, Sepic, and Zeta converters. The proposed IBC shows that since the voltage stress across all the active switches is half of the input voltage before turn-on or after turn-off when the operating duty is below 50%, the capacitive discharging and switching losses can be reduced considerably. This allows the proposed IBC to have higher efficiency and operate with higher switching frequency. In addition, the proposed IBC has a higher step-down conversion ratio and a smaller output current ripple compared with a conventional IBC. The features, operation principles, and relevant analysis results of the proposed IBC are presented in this paper. The validity of this study is confirmed by the experimental results of prototype converters with 150-200 V input, 24 V/10 A output. [ABSTRACT FROM AUTHOR]

• Tailors a coupling circuit for SWER line with a commercially available 1nF/24 kV Coupling Capacitor. • High frequency characteristics analysis of the coupling capacitors with integrated SWER line. • The circuit produce only −4 dB insertion loss for PLC frequency. • Operates in the designated CENELEC frequency band of 50 kHz to 150 kHz. • Reverse AC analysis for the coupling circuit with a 12.7 kV input voltage. • Estimation of voltage and current range of the required inductive or capacitive components. • Utilization of commercially accessible low voltage L and C components. This paper proposes a novel L-C band pass impedance matching circuit for PLC applications coupled to a Single Wire Earth Return (SWER) network via a 1.1 nF High Voltage (HV) Coupling Capacitor (CC). The work begins with characteristic impedance prediction of various SWER conductors followed by an analysis of the theoretical LC-resonant based coupling arrangements. A key finding is that high inductance and capacitance values are required for such LC-resonant based arrangements increasing the cost of solutions. An HV CC is then analysed and its effective capacitance is demonstrated, to be impacted by its internal protection circuitry. An L-C band pass matching circuit is then designed, built and tested as per the derived capacitance of the chosen HV-CC. The proposed coupling circuit produces only −4 dB insertion loss over the targeted 50 kHz to 150 kHz band and includes off-the-self components for a commercially viable solution. The design is based on the capacitance of an HV-CC and uses of off-the-shelf components setting this work aside from comparative works, which only considered hypothetical designs using unviable component values. [ABSTRACT FROM AUTHOR]