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This paper investigates on the theorization, design, fabrication and measurement of original phase shifter (PS) operating with two-step stair phase behavior. The innovative stair PS is designed with unfamiliar stop-band (SB) negative group delay (NGD) passive circuit. The elementary unfamiliar SB-NGD topology constituted by resistive, inductive, and capacitive lumped network is described. Acting as an RF and microwave circuit, the S-matrix model is expressed in function the RLC-network parameters. Thus, the canonical form of unfamiliar SB-NGD transfer function (TF) represented by the transmission coefficient is established. The unfamiliar SB-NGD circuit equations in terms of the NGD parameters are formulated. The established theory is validated comparing the calculated, simulated, and measured S-parameters and group delays (GDs). Results with a very good agreement showing unfamiliar SB-NGD behavior are observed around the central frequency 2.45 GHz and bandwidth of 100 MHz. An innovative application of unfamiliar SB-NGD function for the communication system front-end is developed. The developed application concept of unfamiliar SB-NGD circuit is illustrated by designing a microwave device operating as a PS presenting a two-step stair response completely original behavior. The basic theory, design and implementation of the two-step stair PS concept are introduced. To validate the two-step stair PS principle, a proof of concept (PoC) is designed based distributed element based inductive and capacitive microstrip elements. The simulated and measured results of the PS PoC are in good agreement. The experimental results confirm the feasibility of two-step stair PS with phase jumping from −70°±4° (from 2 GHz to 2.3 GHz) to −104°±2° (from 2.6 GHz to 3.0 GHz). The investigated unfamiliar SB-NGD function-based stair PS is promising for future development 5G and 6G communication system.

The miniaturization and application development are the expected challenges on the today engineering design research on bandpass (BP) type negative group delay (NGD) circuit. To overcome this technical limit, an innovative contribution on integrated circuit (IC) design method of BP-NGD application to design constant phase shifter (PS) in 130-nm BiCMOS technology is developed in the present paper. The BP-NGD PS microwave passive IC is topologically consisted of cascade of CLC- and RLC-resonant networks. After the S-matrix modelling, the synthesis design equations enabling to calculate each lumped component values constituting the BP-NGD PS BiCMOS are established. The design equations are expressed knowing the targeted specifications as phase shift and operating frequency. The BiCMOS design methodology including the key steps as design rule checking (DRC), layout versus schematic (LVS) and post-layout simulation (PLS) is described. The miniaturized BP-NGD PS design feasibility is verified with schematic and layout simulations with IC CMOS standard commercial software tool. A proof-of-concept (POC) of 130-nm BiCMOS BP-NGD PS operating at the center frequency $f_{0}=1.9$ GHz and bandwidth $\Delta f=0.1$ GHz is designed and simulated. After DRC, the chip layout of miniaturized BP-NGD PS POC presents 0.407 mm2 size. The BP-NGD PS POC exhibits constant phase shift notable value of about $\varphi _{0}= - 90^{\circ }+$ /−0.4° under $S_{21}(f_{0})= -6$ +/−1 dB transmission coefficient with good flatness and reflection coefficients ( $S_{21}(f_{0})$ and $S_{21}(f_{0})$ ) widely better than −10 dB. The design robustness is confirmed by 1000-trial Monte Carlo uncertainty analyses with PLS results. Because of the potential integration in wireless sensor networks (WSNs), the BP-NGD PS under study is a promising candidate for the improvement of the future 5G and 6G transceiver design.

This paper develops an innovative design method of a multi-coupled line (CL) topology of low-loss dual band negative group delay (NGD) circuit. The proposed is conceived using three transmission lines (TLs) with different length in which integrate two couplers. The three traveling paths are designed to generate the dual-band NGD effect, where the CLs allow lowering the signal attenuation. The NGD circuit S-parameter model as a function of the TLs physical lengths and coupling coefficient are established. To validate the NGD circuit proof-of-concept, it is fabricated and measured. The NGD values of approximately -4.06 ns and -3.83 ns are measured at center frequencies of 2.43 GHz and 3.02 GHz, respectively. The measured transmission coefficient is better than -2.9 dB and the measured reflection one is better than -12 dB into the NGD band. The measurement results of the NGD circuit are in good agreement with the simulations results.

This paper develops a negative group-delay (NGD) microwave circuit theory regarding topology consists of three parallel interconnect lines (3-PILs). The NGD topology under study is built using completely distributed microstrip lines. The 3-PIL NGD theory is established from the S-parameters which are determined from the general admittance matrix of the 3-PILs. The analytical expressions of reflection coefficient (S11), transmission coefficient (S21) and group-delay (τ) which behave as periodical functions are presented. The frequency period proper to the 3-PIL topology is established. Then, S11, S21 and τ illustrating the possibility to generate bandpass NGD function are formulated in function of the PIL parameter physical lengths and attenuation loss. Then, the NGD characterization of the 3-PIL topology is presented. The relevance of the NGD theory is verified with simulations and experimentations around the NGD center frequency of about 2.3 GHz. To do this, a 3-PIL microstrip circuit is designed and fabricated as proof-of-concept. It is shown that the simulated and measured group-delays are well-correlated. As expected theoretically, the demonstrator with identical characteristic impedance enables to generate an NGD level of approximately -2 ns at 2.3 GHz. In the future, the NGD function can be potentially used for the microwave signal integrity improvement.

Leaks in water distribution systems should be detected to avoid economic, environmental, and social problems. Existing Bayesian Inference based time-domainreflectometry (TDR) methods for leak detection have a limitation for real applications due to the lengthy time in building sample data. As the pipeline distance becomes longer and multiple leaks must be considered in long distance pipelines, the computational time for building training data gets larger. This paper proposes a scattering-parameter-based forward model to relieve computational burden of the existing TDR methods. It was shown that the proposed model outperformed the existing RLGC-based forward model in terms of computational time. The proposed model that is combined with Bayesian inference and TDR signal modeling is validated with an experimental pipeline, leak detectors, transmission line, and TDR instrument for leak detection. In summary, the proposed method is promising for leak detection in long pipelines as well as multiple leaks.

In this paper, a fast method for the calculation of mutual coupling between discontinuities is described. The discontinuities must be small compared to the wavelength and compared to the distance between them. For most circuits, these assumptions are valid. Under these circumstances, the component's (discontinuity) radiation behavior can be accurately modeled by using adequately placed dipoles. This method uses far less unknowns than the method of moments. If the distances between the components become smaller or the components become bigger, then the accuracy can be improved by using more dipoles [ABSTRACT FROM PUBLISHER]

An innovative topology of negative group delay (NGD) microwave circuit based on the interconnected power divider and combiner (PWD/PWC) is investigated. The distributed cell consists of PWD and PWC with the input and outputs interconnected by a transmission line (TL). The theory is based on the S‐parameter modeling. The NGD existence condition is formulated. The NGD properties constituted by the NGD bandwidth, level and figure of merit are introduced. It is shown that the distributed topology behaves as a bandpass NGD circuit. The NGD topology theoretical efficiency is verified with simulations by considering NGD circuit parametric analyses by varying the PWD‐PWC interconnect TL attenuation. To validate experimentally the NGD concept, two prototypes of one‐ and two‐stage passive NGD cells were designed in microstrip technology, fabricated and tested. The one‐ and two‐stage circuit prototypes exhibit NGDs of about −2.2 ns and −4.7 ns with −3.4 dB and −7.5 dB insertion loss, respectively. The NGD phenomenon was generated around 1.85 GHz‐center frequency over about 35 MHz‐NGD bandwidth. [ABSTRACT FROM AUTHOR]