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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]

The purpose of this paper is to study the RF/microwave constant phase shift (CPS) designed as an integrated circuit (IC) in 130-nm Bi-CMOS technology. The CPS understudy is constituted by a bandpass (BP) negative group delay (NGD) passive cell combined in cascade with a positive group delay (PGD) circuit. The CPS real circuit is represented by a CLC-network associated in cascade with a BP-NGD passive cell. The CPS characterization is based on the S-parameter modelling. The CPS is analytically modeled by the frequency independent transmission phase modelling by the mathematical relation φ(f) = a * exp(-j * φ0) = constant around working frequency [fn - Δf/2, fn + Δf/2] by denoting center frequency fn and frequency band Δf. The analytical principle of the constant PS is explored by means of the RLC-network based NGD cell. The design formula of the NGD and CLC passive circuit parameters in function of desired operation frequency is established. The validity of the developed theory is verified with a proof-of-concept (POC). A CPS miniature IC having physical size 1.15mm × 0.7mm is designed and implemented as POCin 130-nm Bi-CMOS technology. The ADS R® and layout versus schematic of Cadence R® simulation results from 130-nm Bi-CMOS CPS POC confirms the theoretical investigation feasibility. The simulated results of the obtained CPS IC POC layout show φ0 = -67◦+/-1◦ phase shift around fn = 0.85 GHz within the frequency band delimited by f1 = 0.73 GHz to f2 = 0.984 GHz or Δf = f2 - f1 = 254 GHz. The CPS robustness designed in 130-nm Bi-CMOS IC technology is stated by Monte Carlo statistical analysis from 1000 trials with respect to the component geometrical parameters. It was reported that the phase shift and insertion loss flatness's of the CPS IC is guaranteed lower than 5% in Δf/fn = 30% relative frequency band around fn. [ABSTRACT FROM AUTHOR]

Ferrites are of great interest for both fundamental science and technological applications due to their outstanding physical, chemical, and magnetic properties. Among various ferrites, Mg‐Zn ferrites is one of the best magnetic materials for researchers due to their unique properties such as high electric resistivity, Curie temperature, low coercivity, low eddy current, dielectric losses, low cost, and better environmental stability. This makes ferrites suitable for many applications such as power transformers, microwave devices, computer memories, logic devices, recording heads, loading coils, antenna rods, color monitoring tubes, telecommunications, hyperthermia, and so forth. Mg‐Zn ferrite nanoparticles have gained increased interest for many applications such as catalysts, antimicrobial potential, and sensors for the detection of combustible gases (CH4, CO, and CO2). In this brief review, the strategies used in the synthesis of Mg‐Zn ferrite nanoparticles are summarized. The different structural, morphological, magnetic, and electric properties of these ferrites are analyzed. [ABSTRACT FROM AUTHOR]

In wireless technology, microstrip patch antennas are often used in communication systems with various designs. However, the effect of geometrically folded antennas on wireless communication performance is unclear. To address this problem, an in-depth study of the exible antenna parameters was performed through V-folding analysis. A systematic and complete analysis of the percentage of folding in patch antennas was performed. The folding of patch antennas is expected to become mandatory because patch antennas are integrated and molded according to specified object shapes. The designed antenna was operated at 0.1{5.0 GHz to investigate the folding performance in the frequency range of 1.00{3.78 GHz used in many wireless applications, such as GPS, GSM, and LTE standards. A promising operating frequency for at (unfold) antennas is 1.42 GHz with an achieved multiband bandwidth of 31.6 MHz, which shifted according to the folding angle 'a' but with good performance. The results of this study can be used to predict the performance of an antenna when it is placed on a product of any shape, according to the designed object pattern. [ABSTRACT FROM AUTHOR]

An original application of stopband (SB) type negative group delay (NGD) electronic function is introduced. The unfamiliar SB-NGD circuit is designed with RLC-network lumped passive topology. The SB-NGD circuit is exploited to operate as a true-time delay (TTD) device for smart dual-beam phased array design. The two-port passive topology for designing an SB-NGD circuit constituted by an RLC-network is described. The theory and design method of the employed SB-NGD passive circuit are detailed. The microwave theory of the SB-NGD topology is elaborated from S-matrix modelling. The SB-NGD canonical form is innovatively introduced in function of the expected specifications. The synthesis design equations allowing to determine the R, L, and C component values in function of the NGD specifications are formulated. The SB-NGD behavior is verified by comparison of calculated and simulated S-parameters from two different proofs-of-concept (POC). Illustrative results with a very good agreement showing SB-NGD behavior are observed around the arbitrarily chosen central frequencies f1 = 0:7 GHz and f2 = 1 GHz over a bandwidth of 50 MHz. The design principle of TTD-based smart dual-beam is described. The dual-band SB-NGD circuit is designed to operate as a dual-band TTD device with fixed delays at t1 (f1) = 357 ps and t2 (f2) = 875 ps, respectively. A radiation pattern showing the smart dual-beam steering operating system at f1 and f2 frequencies is discussed. [ABSTRACT FROM AUTHOR]

This article elaborates on an accurate energy model (EM) for wireless sensor devices (WSDs) based on power consumption measurement. A deep understanding of WSD’s energy cost depends on the WSD’s functional components contributing to the wireless communication process. The model includes different stages of transmission (Tx) and reception (Rx) communication modes. The practical EM is developed with data packet lengths, data rate, operation status, predesigned stages versus appropriate communication bus, and power mode, including mutual data transfers between the microcontroller and the radio module. The validity of the EM is verified through an experimental setup having a TelosB device. As expected, the modeled and measured energy consumed by the WSD operating from 1-to-4-MHz CPU frequencies and the 2-to-100-byte payload is in very good agreement. It was found that, compared to the energy consumption in processing, Tx, listening, and Rx phases, the data transfer consumes up to 40% of total WSD energy, whereas this aspect is often neglected in usual models. Overall, the proposed model provides significant accuracy and might be helpful in improving the energy efficiency of future wireless sensor networks. [ABSTRACT FROM AUTHOR]

This brief explains why the coupling between crossed interconnect structure and straight I-lines of printed circuit board (PCB) presents bandpass (BP) negative group delay (NGD) behavior. The NGD effect is investigated with crossed resonator innovative microstrip equivalent topology. As proof of concept (POC), the influences of crossed resonator circuit physical variables on the BP-NGD behavior are illustrated by parametric study. The cross-coupled microstrip circuit POC BP-NGD responses is validated with quad-band NGD behavior. A very good agreement between calculations, simulations and experimentations state results of NGD center frequency-NGD value, (1.541-GHz, −1.84-ns), (2.397-GHz, −1.6-ns), (3.379-GHz, −1.38-ns), and (4.164-GHz, −0.91-ns) representing the $1^{\mathrm{ st}}$ , $2^{\mathrm{ nd}}$ , $3^{\mathrm{ rd}}$ and $4^{\mathrm{ th}}$ NGD band, respectively. The studied design has notable advantages in term of NGD application integration in the multi-band transceiver system simplicity and size reduction. [ABSTRACT FROM AUTHOR]

This article introduces an innovative design of a low-pass (LP) negative group delay (NGD) integrated circuit (IC) in the 180-nm CMOS technology. The LP-NGD circuit is an inductorless topology constituted by RC-network with CMOS metal-insulator-metal (MIM) capacitor and polygate resistor. The design methodology is illustrated by considering the chip layout process. Then, the first run simulation is performed with the design rule check (DRC) and 2.5 mm ${\times }$ 2.2 mm layout versus schematic (LVS) approaches. The feasibility of the CMOS LP-NGD IC circuit implementation is validated with chip-onboard (CoB). The proof of concept (PoC) of the LP-NGD miniaturized circuit was tested in both S-parameter and time domain (TD). As expected, the calculated, simulated, and experimented results of CoB showing NGD of about −10 ns over 12 MHz and −10 dB attenuation are confirmed. The active CMOS LP-NGD technology compensates the insertion loss to 2.4 dB, the GD reaches −11 ns, and the reflection loss reaches −20 dB. Moreover, TD investigations were also performed to show the feasibility of generating pulse and arbitrary waveform signal time advance through the designed and fabricated LP-NGD CoB prototypes. [ABSTRACT FROM AUTHOR]

This paper explores an original study of bandpass (BP) negative group delay (NGD) robustness applied to the ring-stub passive circuit. The proof of concept (PoC) circuit is constituted by a ring associated with the open-end stub implemented in microstrip technology. An innovative experimental setup of a temperature room containing the NGD PoC connected to a vector network analyzer is described. Then, the electrothermal data of S-parameters are measured by varying the ambient or room temperature range from 20 to 60°C, i.e. 40°C maximal variation. The empirical results of the group delay (GD), transmission and reflection coefficient mappings versus the couple (temperature, frequency) highlight how the temperature affects the BP NGD responses. An innovative electrothermal calibration technique by taking into account the interconnection cable influence is developed. The electrothermal robustness analysis is carried out by variations of the NGD center frequency, cut-off frequencies and value in function of the temperature. [ABSTRACT FROM AUTHOR]

Cobalt nanoferrites are one of the most commonly used ferrites and have a wide range of applications. The present study involves several synthesis and characterization methods along with applications of cobalt ferrite nanoparticles. The selection of routes to prepare these nanoferrites was found to be dependent on the required properties of materials to be synthesized. All the available methods to synthesize the nanomaterials have their advantages and limitations that are discussed in detail. Numerous tools have been employed to analyze the properties of these nanomaterials. Among all these tools, XRD (X-ray diffraction) method and FT-IR spectroscopy are noticed as the most popular for precise structural analysis. The morphology has been determined using SEM (scanning electron microscopy) and TEM (transmission electron microscopy) in almost all studies. Owing to its exceptional characteristics, the cobalt nanoferrites have been found to be immensely utilized in multiple areas of applications such as microwave devices, MRI (magnetic resonance imaging), and hyperthermia. [ABSTRACT FROM AUTHOR]

This article introduces an original microcontroller unit (MCU) design of numerical low-pass (LP) negative group delay (NGD) function. The innovative theory of the numerical LP-NGD function is developed based on the first-order analog transfer function discretization. The infinite impulse response (IIR) LP-NGD is fundamentally formulated in function of the desired NGD value, cutoff frequency, gain, and the MCU sampling frequency. A STM32 MCU proof-of-concept (POC) is tested to implement the IIR LP-NGD function. Different real-time tests with visualization of input and output analog signals from the MCU LP-NGD POC were performed. As expected, time-advance demonstration tests with milli-second short- and several hour long-duration time-scale with arbitrary waveform signals from temperature and humidity sensors. The signal time-advance is not in contradiction with the causality. The proposed digital MCU function opens a potential future industrial application of LP-NGD function via sensored signal anticipation. [ABSTRACT FROM AUTHOR]

This paper develops an innovative model of bandpass (BP) negative group delay (NGD) inverted arm topology of parallel lines. The S-matrix model is established from impedance and admittance matrix operations of elementary transmission lines constituting the topology. Parametric analysis is performed to assess the influence of inverted arm structure sizes on the BP NGD specifications. To validate the theoretical concept, a proof of concept is designed in microstrip technology. The calculated and simulated results are in very good agreement. NGD value, center frequency and bandwidth of about −8 ns, 3.6 GHz and 4 MHz, respectively, are observed with insertion loss better than 1 dB and reflection loss better than 18 dB. The innovative NGD physical structure could be an important asset to reduce propagation delay in the upcoming telecommunications systems as the 5G system. [ABSTRACT FROM AUTHOR]

A design method of low‐pass (LP) negative group delay (NGD) integrated circuit (IC) implemented in 130‐nm BiCMOS technology is investigated. The LP‐NGD circuit is composed by RL‐network with BiCMOS high Ohmic unsalicided N+poly resistor and symmetrical high current spiral inductor. The design methodology of the investigated LP‐NGD circuit is explained by chip layout process. Then, the pre‐simulation is performed with the design rule check (DRC) and 225 μm × 215 μm layout versus schematic (LVS) approaches. The LP‐NGD design feasibility of the BiCMOS IC implementation is validated by AC frequency domain simulation with realistic component implementation constraints. As expected, the ideally calculated and simulated results show NGD of about −100 ps with 1.12 GHz cut‐off frequency and −6 dB attenuation. Moreover, the LP‐NGD function is also verified with transient analyses with Gaussian pulse and arbitrary waveform signals. As expected, despite the attenuation, the output signal leading and tailing edges appear in time‐advance of about −100 ps compared to the input ones. [ABSTRACT FROM AUTHOR]

The main characteristics of geological flows such as debris flows, avalanches and lahars is due to the relative importance of viscous versus inertial forces in the momentum balance. This paper considers the motion generated by the collapse of a dam-retaining mud, itself modeled as a power-law fluid. The equation of motion is derived in a non-dimensional form and solved analytically with the shallow-water assumption in a dry and smooth horizontal channel. Notably indicated are flow regimes and the effect of the reservoir length as well as the effect of mud rheology on flow development. Then, a parametric study of this model is produced and the effect of mud shear-thinning on flow development is pointed out.

The negative group delay (NGD) is one of less familiar electronic functions. So far, the time domain (TD) experimentation of NGD circuits remains a challenging task. This paper investigates an innovative TD measurement of a band‐pass (BP) NGD passive circuit. The topology of the considered BP NGD distributed circuit constituted by transmission line structure having a 101O‐geometrical shape is introduced. After the design description of the 101O‐structure, the NGD response illustrates from simulation and measurement based on S‐parameters. The NGD center frequency, bandwidth, and value are approximately 3.6 GHz, 33 MHz, and −4.9 ns, respectively. The TD measurement experimentation is based on the sine carrier‐modulated microwave signal generation with 50‐ns duration. The 101O‐NGD circuit input and output signals are plotted with innovative synchronization. It was shown from the TD‐simulated and measured results that the BP NGD effect induces an output envelope about 4.2 ns advanced of the test signal input. Key Points: This study investigates a band‐pass (BP) negative group delay (NGD)The topology of the considered BP NGD distributed circuit is constituted by transmission line structure having a 101O‐geometrical shapeThe circuit behaves as a BP NGD function with center frequency of about 3.6 GHz and NGD value of about −3.6 ns [ABSTRACT FROM AUTHOR]

This paper develops a bandpass (BP) negative‐group‐delay (NGD) analysis of multi‐port topology. The circuit under study consists of resistorless symmetric coupler constituted by passive LC‐networks. By using the tensorial‐analysis‐of‐networks (TAN) formalism, an innovative study enables to verify if the four‐port circuit is susceptible to exhibit the unfamiliar BP‐NGD function. Using the TAN formalism, the different steps of the method is described from the branch and mesh spaces via the tensor connectivity to determine the equivalent S‐parameters. The general methodology of the S‐matrix modeling is expressed in the function of the coupler L and C parameters. To validate the BP‐NGD behavior, an arbitrary parametrized lumped four‐port coupler is considered as a proof‐of‐concept. The feasibilities of the TAN S‐parameter modeling added by the BP‐NGD function is validated comparison results between TAN mathematical calculations and simulations from a commercial tool. Excellent correlations between the calculated and simulated results are confirmed with BP‐NGD behavior of the connections between port 1 and port 2 with −30 ns NGD value at the center frequency, 124 MHz, and between port 1 and port 4 with −27 ns NGD value at the center frequency, 92 MHz. The present results confirm a scientific result never being found before, the first time, which demonstrates the possibility to generate the BP‐NGD function with a four‐port resistorless circuit. The TAN method flexibility advantages are the flexibility to lumped and distributed circuits. However, the sensitivity to the component inaccuracies constitute the main drawbacks. Key Points: A bandpass‐negative‐group‐delay (BP‐NGD) analysis of resistorless LC‐network topology is developedTensorial‐analysis‐of‐networks is elaborated for BP‐NGD analysisThe resistorless LC‐network proof‐of‐concept operates innovatively as BP‐NGD circuit [ABSTRACT FROM AUTHOR]

Most of the recent studies on unfamiliar negative group delay (NGD) circuit were focused on the classes of low‐pass (LP) and bandpass (BP) topologies. So far, few research works are currently available in the literature on the high‐pass (HP) NGD class. This paper introduces an original HP‐NGD circuit theory of four‐port passive topology constituted by a single lumped capacitor. The S‐matrix equivalent model of the innovative topology is established from the admittance matrix. The basic analytical frequency‐dependent responses are expressed. Then, the GD model is derived in function of the capacitor. It was analytically found that the four‐port mono‐capacitor passive circuit is susceptible to behave as an unfamiliar class of HP‐NGD function. An innovative HP‐NGD analysis is explored in addition to the expression of synthesis design equation in function of the expected NGD cut‐off frequency which is linked to NGD optimal value. The validity of the established HP‐NGD theory is verified with a proof of concept (POC) circuit. As expected, the POC enables HP‐NGD behavior to show a good correlation between analytical model which is confirmed by the simulation. [ABSTRACT FROM AUTHOR]

This paper develops an original theory of bandpass (BP) negative group delay (NGD) function from three-port symmetric circuit. The BP NGD analysis is applied first time to three-port topology. The present study develops originally a BP NGD investigation of three-port circuit constituted by R, L and C lumped components. The equivalent S-matrix modelling is elaborated with the uncommon circuit theory. To validate the theory, a lumped circuit proof of concept is designed and simulated. A group delay value of about −0.3 ns is observed at the NGD centre frequency of about 76 MHz over 214 MHz bandwidth. For the further understanding on the BP NGD behaviour, a parametric study with the variations of the resistor, inductor and capacitor components of the Y-tree is performed. The results of the present study guarantee a potential microwave communication application of BP NGD function notably for systems operating with ISM and IEEE 802.11 standards. [ABSTRACT FROM AUTHOR]

This paper explains why the electromagnetic coupling between interconnect main Ω‐shape and straight I‐lines of printed circuit board (PCB) can be source of bandpass (BP) negative group delay (NGD) behavior. The investigation on the NGD effect is established from an innovative microstrip circuit having medusa shape. The medusa topology analytical description is based on the equivalent circuit and S‐matrix model. Then, the group delay (GD) response enabling to explain the existence of the BP NGD function is defined. As proof‐of‐concept (POC), the influences of the medusa circuit constituting interconnect line (IL) lengths and interspaces on the BP NGD behavior are illustrated by parametric study. The NGD behavior is explained by the variations of the NGD value and NGD center frequency. More importantly, two NGD medusa prototypes were designed, fabricated, simulated and tested. The BP NGD responses of the two‐medusa circuit POCs are validated by a very good agreement between the calculations, simulations and experimentations. The test results confirm that the medusa circuit POCs generate BP NGD responses with NGD level and center frequency of about −1.6 ns and 2.76 GHz respectively. [ABSTRACT FROM AUTHOR]

This article deals with an original equalization method of 3-D electromagnetic (EM) cavity resonance by using bandpass negative group delay (NGD) function. Based on the equivalent circuit, the S-matrix model of the equalized EM cavity is introduced. The design equations of the NGD function are established in function of the cavity physical parameters. The feasibility of the equalization method is validated with a 42×28×3.8 cm rectangular cavity containing two communicating monopole antennas. By considering the TE110-mode, a significant equalization is realized with improvement of transmission coefficient flatness from 4 dB to less than 0.3 dB. In addition to the magnitude, the NGD equalization method enables to outstandingly reduce spikes of 3-D EM cavity group delay. With the proof of concept, the GD is reduced from more than 4 to 1 ns. [ABSTRACT FROM AUTHOR]

This brief introduces an original reduction method of resonance effect dispersion by using bandpass negative group delay (NGD) function. The dispersion transfer function (TF) is model by lumped RLC circuit. The canonical parameters of NGD passive cell are innovatively formulated as a function of the resonance dispersion specifications. The developed method feasibility is validated with commercial tool frequency domain simulations. Proofs-of-concept constituted by passive RLC-resonant and NGD fully passive circuits are considered. The results confirm an obvious peak reduction of resonance magnitudes and GDs from (15-dB, 20-ns) to better than (11.5-dB, 8.6-ns) are realized in the NGD bandwidth of about 20 MHz. The NGD method robustness is also investigated with simultaneous and individual relative variations of the dispersion parameters. [ABSTRACT FROM AUTHOR]

Summary: The aim of this article is to demonstrate the interest of the optimized clustering method (OCM) when dealing with the yield analysis of ring oscillators, given uncertain assumptions over inputs. Indeed, the complementary metal–oxide semiconductor (CMOS) integrated circuit domain is facing a major challenge since these devices are subjected to noticeable fluctuations (mostly due to transistor constant scaling down at sub‐micron sizes), with utmost expectations regarding their performances (e.g., for digital circuits). Whether the classical approach requires use of Monte Carlo methods coupled with classical circuit solver (e.g., Spice and/or transistor model), the natural complexity of systems and varying inputs needs to provide alternative techniques, such as OCM. The foundations of the method and its efficiency will be presented and illustrated through ring oscillator applications. [ABSTRACT FROM AUTHOR]

In this paper, new bridged-T network operating with bandpass (BP) negative group delay (NGD) function is introduced. The circuit design is innovatively based on an inductorless passive RCnetwork. The innovative bridged-T topology is implemented with a R-shunt configuration. The analytical transfer function of voltages and equivalent impedance-matrix are carefully calculated. The BP NGD analysis and design of the bridged-T topology is developed. The BP NGD properties and specifications are analytically investigated. A proof of concept of R-shunt bridged-T prototype with a surface-mounted device printed circuit board is designed, fabricated, and measured to verify the BP NGD behavior from theoretical equations and simulations. As expected, the theoretical, simulation, and measurements results are in very good agreement. From measurement results, the fabricated BP NGD C-shunt bridged-T reaches a delay of about -45 ns and a center frequency of about 0.5 MHz over a -3 dB attenuation. [ABSTRACT FROM AUTHOR]

This paper investigates a negative group delay (NGD) design of Ulu geometrical shape circuit. The NGD basic topology is constituted by a coupled line coupler with two-port terminated by open-ended stub. The S-matrix model of the topology is presented. The design equations allowing to determine the NGD circuit parameters in function of the NGD function specifications, NGD center frequency, NGD values and insertion loss are presented. As proof of concept, a microstrip circuit is designed and fabricated. As expected, the tested results confirm that the circuit behaves as bandpass NGD function. The modeled, simulated and measured results are in good correlation. The POC operates with tri-band NGD behavior with center frequencies around 0.645, 1.285, and 1.87 GHz with NGD values of about -3.5, -2, and -1 ns, respectively. [ABSTRACT FROM AUTHOR]

This paper introduces a bandpass (BP) NGD circuit design engineering. The developed circuit is designed and implemented using distributed microstrip technology and operates with outstanding dual-band bandpass NGD performance added with low attenuation. The BP NGD topology presents an innovative geometrical shape represented by an OOO (triple O) structure composed of multi-parameter parallel transmission lines (TLs) based elements. The OOO type NGD circuit is mainly composed of different physical length TLs and two identical coupled lines (CLs). Then extensive parameter NGD analyses are elaborated to investigate on the influences of each physical size of OOO circuit on the NGD performances. Through the difference of physical length of transmission line, the delay can be adjusted. Through the results of simulation and measurement, it can be seen that the center frequency points are about 0.75 GHz and 1.46 GHz respectively, and the time delay is about –1.83 ns and –2.6 ns respectively. [ABSTRACT FROM AUTHOR]

This study investigates an innovative theory on design of dielectric resonator (DR) based negative group delay (NGD) microwave circuit. The NGD circuit is mainly constituted by a cylindrical bulk of DR as a coupling element with a microstrip line. The developed theory is analytically established from the S‐parameters modeling of this innovative DR NGD topology. The NGD analysis and synthesis equations are formulated by considering the key parameters of the DR NGD cell. The NGD existence condition as a function of the DR and microstrip line parameters is also introduced. The behavioral response of the bandpass NGD function is verified with different designed proof‐of‐concepts (POCs). The developed NGD DR topology was validated with original circuit design by commercial simulations and experimentations with insertion and reflection losses lower than 4 and 10 dB, respectively. The POC prototypes operate with low attenuation losses in mono band and dual bands up to 10 GHz. Single NGD cells with DR coupled with "I" and "U" shape microstrip lines operating at different central frequencies were designed and implemented. Then, dual‐band NGD circuits operating at approximately 2.5 and 5 GHz were also tested. The possibility to widen the NGD bandwidth with double DR NGD circuits was investigated. Key Points: This study investigates an innovative theory on the design of dielectric resonator (DR) based negative group delay (NGD) microwave circuitThe possibility to widen the NGD bandwidth with double DR NGD circuits is investigated [ABSTRACT FROM AUTHOR]

The present paper develops an application of the bandpass (BP) negative group delay (NGD) circuit for the design of an independent frequency phase shifter (PS). The design principle of the innovative PS is constituted by an inductor-capacitor-inductor (LCL) T-shape passive cell in cascade with RLC-network series-based BP NGD circuits. The S-matrix analytical model of the LCL-NGD PS is established in function of the circuit elements. Then, the design equations of the PS elements in the function of the expected PS value and center frequency are formulated. The NGD PS topology is validated with a comparison between the calculated and simulated results of phase, transmission coefficient, and reflection coefficients. As expected, a very good correlation between the analytical model and the simulation is confirmed by the obtained results. It is found that the LCL-NGD PS presents an outstandingly flat phase shift of -120° ±5° with 1.2GHz center frequency. The LCL-NGD PS operates with about 18% relative bandwidth. The PS reflection coefficient presents a magnitude flatness around -3±1.5 dB. Moreover, the reflection coefficient is kept better than -15 dB. The sensitivity of the LCLNGD PS performances over the NGD circuit element ±5% relative variation is studied. It is found how the PS value and center frequency change with the R, L, and C components of the NGD circuit. [ABSTRACT FROM AUTHOR]