PIER B | PIER Journals

2023-11-29

PIER B

Vol. 104, 21-33, 2024

download: 32

The Influence of Contrast and Temporal Expansion on the Marching-on-in-Time Contrast Current Density Volume Integral Equation

Petrus Wilhelmus Nicolaas (Pieter) Van Diepen , Martijn Constant van Beurden and Roeland Johannes Dilz

The contrast current density volume integral equation, discretized with piecewise constant spatial basis and test functions and Dirac-delta temporal test functions and the piecewise polynomial temporal basis functions, results in a causal implicit marching-on-in-time scheme that we refer to as the marching-on-in-time contrast current density volume integral equation (MOT-JVIE). The companion matrix stability analysis of the MOT-JVIE solver shows that for a fixed spatial and temporal step size, the stability is independent of the scatterer's dielectric contrast for quadratic spline temporal basis functions. Whereas, Lagrange and cubic spline exhibit instabilities at higher contrast. We relate this stability performance to the expansion and testing procedure in time. We further illustrate the capabilities of the MOT-JVIE based on quadratic spline temporal basis functions by: comparing the MOT-JVIE solution to time-domain results from literature and frequency-domain results from a commercial combined field integral equation solver. Finally, we present a long time sequence for a high-contrast scatterer discretized with 24,000 spatial unknowns.

The Influence of Contrast and Temporal Expansion on the Marching-on-in-Time Contrast Current Density Volume Integral Equation

2023-11-24

PIER B

Vol. 104, 1-19, 2024

doi:10.2528/PIERB23060902

download: 80

BI-CMOS Design of a*exp (-j *φ0) Phase Shifter as Miniature Microwave Passive Circuit Using Bandpass NGD Resonant Circuit

Mathieu Guerin , Fayrouz Haddad , Wenceslas Rahajandraibe , Samuel Ngoho , Glauco Fontgalland , Fayu Wan and Blaise Ravelo

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 [f_n-Δf/2, f_n+Δf/2] by denoting center frequency f_n 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 1.15 mm × 0.7 mm is designed and implemented as POC in 130-nm Bi-CMOS technology. The ADS® and layout versus schematic of Cadence® 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 f_n=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/f_n=30% relative frequency band around f_n.