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This paper introduces a design method of simple bandpass (BP) negative group delay (NGD) topology. The fundamental specifications of BP NGD function are defined. The NGD passive topology consists of parallel resistance associated with an open-ended microstrip stub. The NGD properties and characterization with respect to the constituting stub parameters are established. The validations are performed with theoretical calculated and simulated GD, transmission and reflection coefficients. The BP NGD circuit can be useful for the improvement of phase linearity and GD equalization of future 5G microwave devices.

One of the major challenges of today’s rotating machine manufacturing industries is finding effective techniques to prevent early mechanical or electrical failure. Efficient troubleshooting methods must be developed for rotating electrical machines, such as three-phase and multiphase electrical induction or synchronous machines. A novel method for fault detection in a Wound Rotor Induction Machine (WRIM) is presented in this paper. Its originality lies in the determination of current rise and fall times in healthy and InterTurn short-Circuit Fault (ITSCF) cases. The method is based on using the two-current (isd, isq) sigmoid transform (ST) of Park’s vector approach. A WRIM with a nominal power of 0.3 kW is used for the analytical and experimental studies. The type of fault detection being studied is short circuit InterTurns on one phase of the stator winding. The results are promising because the methodology used is simple, fast, and accurate for diagnosing this type of fault, and can detect a low number of short-circuit InterTurns in the stator winding. [ABSTRACT FROM AUTHOR]

The folding antennas are anticipated to become mandatory because of integration necessity according to communication object shapes. The effect of folded antennas on electromagnetic (EM) radiation is an open question for RF and microwave wireless engineers. An innovative approach to explore the flexible patch antenna (FPA) parameters through V-folding analysis is addressed for this problem. This paper is focused on the methodological approach of the FPA study by considering an innovative V-folding behavior compared to the classical flat condition. As a proof-of-concept, FPA prototypes are designed on a Kapton substrate, simulated, fabricated, and tested. A non-shifting operating frequency is achieved at 3.4 GHz for all percentage-wise folding with a flat (unfold) bandwidth about 360.8 MHz with good acceptable performance. The FPA performance prediction as reflection coefficient, efficiency, gain, and directivity versus forward and back V-folding percentage and angle are examined. The obtained result can be exploited to predict the V-folding effect on the communication performances of transceiver systems like radar, satellite, and multimedia applications. [ABSTRACT FROM AUTHOR]

The present study examines the negative group delay (NGD) behavior of a circular curved (CC) coupled-line (CL) microstrip circuit with a bandpass (BP) characteristic. The novel CC CL-based circuit is derived from the curved li-topology which demonstrates BPNGD functionality. The basic theoretical approach enabling the BP-NGD analysis is introduced. The BP-NGD function main properties related to NGD center frequency, NGD value, and NGD bandwidth are defined. Despite the progressive NGD research work, it was wondered how the RF printed circuit board trace geometrical parameters such as curvature radius and angle change the microwave communication parameters. To verify the BP-NGD concept feasibility, different microstrip prototypes are designed, simulated, fabricated, and tested as the proof of concept (POC). Thus, a developed empirical study of CC microstrip structures corroborating well-correlated simulations and experimental results is examined. Moreover, deep sensitivity analyses for geometrical design parameters were performed using commercial tool full-wave simulations. The obtained results provide insights into the effects of CC-structure inter-space and curvature angles on the inherent BP-NGD parameters. The proposed NGD circuit is potentially useful in the future in RF and microwave engineering for signal delay correction. Additionally, it helps in understanding the characteristics of microstrip PCB traces that are important for optimizing signal integrity (SI), power integrity (PI), and electromagnetic compatibility (EMC). [ABSTRACT FROM AUTHOR]