This paper introduces an original study of low-pass (LP) negative group delay (NGD) circuit. The family of the proposed passive network cross-topology was rarely investigated in the literature. It acts as a tri-port passive circuit presenting a cross-shaped topology. The present study of tri-port passive circuit is originally based on S-matrix modelling. The identification method of LP-NGD function type is established. The considered passive tri-port topology is innovatively constituted by a resistorless LC-passive network. Thanks to the impedance 3-D matrix modelling, the cross-circuit S-parameters are analytically expressed. Then, the NGD analysis at very low-frequencies is presented. The LP-NGD behavior existence condition of the cross-circuit in function of the L and C components is established. The relevance of the tri-port NGD circuit theory is verified by a proof-of-concept of resistorless cross-circuit. Analytical modelling, simulation, and experimentation confirmed the LP-NGD design feasibility with NGD value of about −2 ns and 6.67 MHz cut-off frequency.

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Different methods to achieve zero-energy and low carbon on the scale of a building are shown by most of the research works. Despite this, the recommendations generally offered by researchers do not always correspond to the realities found during the construction of new buildings in a determined region. Therefore, a standard may not be valid in all climate regions of the world. Being aware of this fact, a study was carried out to analyse the design of new buildings respecting the “zero-energy and low carbon emission” concept in tropical climatic regions when they are compared with a base case of temperate regions. To reach this objective, the comparison between real and simulated data from the different buildings studied was developed. The results showed that the renovation of existing residential buildings allows for reducing up to 35% of energy demand and a great quantity of CO2 emissions in both climate types. Despite this, the investment rate linked to the construction of zero-energy buildings in tropical zones is 12 times lower than in temperate zones and the payback was double. In particular, this effect can be related to the efficiency of photovoltaic panels, which is estimated to be, at least, 34% higher in tropical zones than temperate zones. Finally, this study highlights the interest and methodology to implement zero-energy buildings in tropical regions.

Purpose The purpose of this paper is to introduce an innovative theoretical, numerical and experimental investigations on the HP NGD function. The identified HP NGD topology under study is constituted by first order passive RC-network. The simulations and measurements confirm in very good agreement the HP NGD behaviors of the tested circuits. NGD responses with optimal values of about -1 ns and cut-off frequencies of about 20 MHz are obtained. Design/methodology/approach The identified HP NGD topology understudy is constituted by a first-order passive Resistor-capacitor RC network. An innovative approach to HP NGD analysis is developed. The analytical investigation from the voltage transfer function showing the meaning of HP properties is established. Findings This paper introduces innovative theoretical, numerical and experimental investigations on the HP NGD function. Originality/value The NGD characterization as a function of the resistance and capacitance parameters is investigated. The feasibility of the HP NGD function is verified with proofs of concept constituted of lumped surface mounted components on printed circuit boards. The simulations and measurements confirm in very good agreement the HP NGD behaviors of the tested circuits. NGD responses with optimal values of about −1 ns and cut-off frequencies of about 20 MHz are obtained.

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