Susceptibility to Low-Frequency Breakdown in Full-Wave Models of Liquid Crystal-Coaxially-Filled Noise-Shielded Analog Phase Shifters DOI Open Access
Jinfeng Li, Haorong Li

Electronics, Год журнала: 2024, Номер 13(23), С. 4792 - 4792

Опубликована: Дек. 4, 2024

Building on the fully encapsulated architecture of liquid crystal (LC) coaxial phase shifters, which leverages noise-shielding advantages for millimeter-wave wideband reconfigurable applications, this study addresses less-explored issue low-frequency breakdown (LFB) susceptibility in modern full-wave solvers. Specifically, it identifies vulnerability nexus between tuning states (driven by bias voltages) and constitutive elements LC-filled shifters—namely, core line, housing grounding, radially sandwiched tunable dielectrics—operating at frequencies (60 GHz WiGig), microwave (1 GHz), far lower frequency regimes (down to 1 MHz, kHz, Hz) long-wavelength or quasi-static conditions, with specialized applications submarine communications geophysical exploration. For completeness, also investigates device state prior LC injection, when cavity is air-filled. Key computational metrics, such as effective permittivity characteristic impedance, are analyzed. The results show that deviations exceed four orders magnitude compared GHz, while impedance exhibits three magnitude. More critically, LFB regime, theoretical benchmarks from MHz kHz Hz demonstrate an exponential increase prediction error both permittivity, rising 16.8% 1.5 × 104% 107%, escalating 8.1% 1.15 103% 3.9 104%, respectively. Consequently, differential shift, minimal 60 (0.16%), becomes noticeable (4.39%), increases sharply 743.88% escalates dramatically 2.18 1010% Hz. findings reveal a pronounced asymmetry shifter biased extremely low frequencies.

Язык: Английский

Modeling 0.3 THz Coaxial Single-Mode Phase Shifter Designs in Liquid Crystals with Constitutive Loss Quantifications DOI Creative Commons
Jinfeng Li, Haorong Li

Crystals, Год журнала: 2024, Номер 14(4), С. 364 - 364

Опубликована: Апрель 11, 2024

This work proposes and examines the feasibility of next-generation 0.3 THz phase shifters realized with liquid crystals (LCs) as tunable dielectrics coaxially filled in transmission line. The classic coaxial line topology is robust to electromagnetic interference environmental noise, but susceptible higher-order modes from microwave millimeter-wave towards terahertz (THz) wavelength ranges, which impedes low-insertion-loss phase-shifting functionality. thus focuses primarily on suppression risky modes, particularly first emerging TE11 mode impacting dielectric loss metal losses diverse manners. Based impedance matching baselines at tuning states LCs, this analytically derives models two design geometries; i.e., 1 for geometry matched isotopically referenced state LC 50 Ω, 2 saturated bias maximally achievable permittivity. Figure-of-Merit reports 35.15°/dB 34.73°/dB per unit length, respectively. We also propose a constitutive power analysis method understanding consumed by materials. Notably, design, isotropic results an 63.5% total input (assuming 100%), becomes primary constraint achieving low-loss operations. substantial difference between (35.76% variation) compared that our past 60 GHz (13.5% indicates loss’s escalating role further enhanced rise frequency, more pronounced than conductor losses. Overall, analytical finite-element optimization shape direction unconventional shifting technology actioned continuously dielectrics.

Язык: Английский

Процитировано

7
Liquid Crystal Technology for IoT and Beyond: Advancements and Future Directions DOI
Jinfeng Li,

H. Li

Опубликована: Фев. 11, 2025

Язык: Английский

Процитировано

0
Introductory Chapter: Establishing New Life in Terahertz Reconfigurability DOI
Jinfeng Li

IntechOpen eBooks, Год журнала: 2025, Номер unknown

Опубликована: Апрель 10, 2025

Язык: Английский

Процитировано

0
Effective Dielectric Constant Benchmark of 60 GHz Liquid Crystal-Filled Coaxial Delay Line DOI
Jinfeng Li, Haorong Li

Опубликована: Апрель 15, 2024

Gaining exact knowledge of the effective permittivity for liquid crystal-filled delay lines (LCF-DL) is fundamental to precise prediction variable time-delaying functionality. This work semi-theoretically and computationally benchmarked above quantities a coaxially structured LCF-DL that operates at 60 GHz. Decent agreement computed line with intrinsic dielectric constant filler material observed, deviation less than 0.0045 maximally thickness between 0.2 mm 0.5 mm. The numerically validated nearly-perfectly-true transverse electromagnetic nature proposed coaxial V band provides useful implications future devices' quick prototyping without capital-intensive full-wave simulators.

Язык: Английский

Процитировано

2
Computationally Sampling Surface and Volume Current Densities of Liquid Crystal Non-Planar Phase Shifters for Low-Loss 5G IoT and 6G AIoT DOI
Jinfeng Li, Haorong Li

Опубликована: Июль 29, 2024

Язык: Английский

Процитировано

2
Symmetry Implications of a 60 GHz Inverted Microstrip Line Phase Shifter with Nematic Liquid Crystals in Diverse Packaging Boundary Conditions DOI Open Access
Jinfeng Li, Haorong Li

Symmetry, Год журнала: 2024, Номер 16(7), С. 798 - 798

Опубликована: Июнь 25, 2024

This work demystifies the role that packaging boundary conditions (both physically and electromagnetically) can play in a nematic liquid crystal (NLC)-based inverted microstrip (IMS) phase shifter device operating at 60 GHz band (from 54 to 66 GHz). Most notably, air box radiating perfect electric conductor (PEC) enclosing are numerically examined compared statistically for convergence, scattering parameters, phase-shift-to-insertion-loss ratio, i.e., figure-of-merit (FoM). Notably, simulated tunability of structure is 8.26°/cm higher than encased (enclosed) PEC GHz. However, maximum insertion loss 0.47 dB smaller radiant structure. results an FoM increase 29.26°/dB enclosed limit (relative less-than-optimal airbox radiation limit). Arguably, NLC-filled IMS with metals fully (in addition default ground plane) enhances symmetry structure, both geometry materials system. In electromagnetic parlance, it contributes more homogenously distributed field stable monomodal transmission environment mitigated noise. Practically, enclosure well-established NLC-IMS planar fabrication techniques provides feasible manufacturing (assembling) solution acquire reasonably comparable performance advantage exhibited by non-planar structures, e.g., strip line rectangular coaxial line, which technically demanding manufacture NLC.

Язык: Английский

Процитировано

2
Navigating Aspect Ratio Effects in Response Time Challenges of Liquid Crystal Coaxial Phase Shifters for Next-Generation mmW Communications DOI
Jinfeng Li, Haorong Li

Опубликована: Июль 23, 2024

Язык: Английский

Процитировано

2
Assessing Vulnerabilities in Line Length Parameterization and the Per-Unit-Length Paradigm for Phase Modulation and Figure-of-Merit Evaluation in 60 GHz Liquid Crystal Phase Shifters DOI Open Access
Jinfeng Li, Haorong Li

Symmetry, Год журнала: 2024, Номер 16(10), С. 1261 - 1261

Опубликована: Сен. 25, 2024

The figure-of-merit (FoM) is a crucial metric in evaluating liquid crystal (LC) phase shifters, significantly influencing the selection of superior device candidates. This paper identifies, for first time, fundamental limitation widely-used High-Frequency Structure Simulator (HFSS), closed-source commercial tool, when modeling reconfigurable delay line shifters (RDLPS) based on LC at millimeter-wave (mmW) frequencies Beyond 5G (B5G) and Sixth-Generation (6G) applications. Specifically, study reveals unreliable predictions differential shifts (DPS) using length parameterization (LLP) approach, with an accuracy only 47.22%. These LLP-induced inaccuracies lead to misleading FoM calculations, potentially skewing comparative analyses against implemented different geometries or advanced technologies. Additionally, per-unit-length (PUL) paradigm, commonly employed by microwave circuit engineers optimizing transmission designs, also found have limitations context mmW RDLPS LC. PUL methodology underestimates 1.38206°/dB coaxial 60 GHz. findings underscore critical symmetry implication, where assumed shift response violated, resulting inconsistent performance assessments. To address these challenges, remediation strategy scenario-based “Length-for-π” (LFP) framework proposed, offering more accurate characterization enabling better-informed decision-making shifter design.

Язык: Английский

Процитировано

1
Liquid Crystal Coaxial Phase Shifter Designs at 0.3 THz DOI
Jinfeng Li, Haorong Li

Springer proceedings in physics, Год журнала: 2024, Номер unknown, С. 147 - 151

Опубликована: Янв. 1, 2024

Язык: Английский

Процитировано

0
Susceptibility to Low-Frequency Breakdown in Full-Wave Models of Liquid Crystal-Coaxially-Filled Noise-Shielded Analog Phase Shifters DOI Open Access
Jinfeng Li, Haorong Li

Electronics, Год журнала: 2024, Номер 13(23), С. 4792 - 4792

Опубликована: Дек. 4, 2024

Building on the fully encapsulated architecture of liquid crystal (LC) coaxial phase shifters, which leverages noise-shielding advantages for millimeter-wave wideband reconfigurable applications, this study addresses less-explored issue low-frequency breakdown (LFB) susceptibility in modern full-wave solvers. Specifically, it identifies vulnerability nexus between tuning states (driven by bias voltages) and constitutive elements LC-filled shifters—namely, core line, housing grounding, radially sandwiched tunable dielectrics—operating at frequencies (60 GHz WiGig), microwave (1 GHz), far lower frequency regimes (down to 1 MHz, kHz, Hz) long-wavelength or quasi-static conditions, with specialized applications submarine communications geophysical exploration. For completeness, also investigates device state prior LC injection, when cavity is air-filled. Key computational metrics, such as effective permittivity characteristic impedance, are analyzed. The results show that deviations exceed four orders magnitude compared GHz, while impedance exhibits three magnitude. More critically, LFB regime, theoretical benchmarks from MHz kHz Hz demonstrate an exponential increase prediction error both permittivity, rising 16.8% 1.5 × 104% 107%, escalating 8.1% 1.15 103% 3.9 104%, respectively. Consequently, differential shift, minimal 60 (0.16%), becomes noticeable (4.39%), increases sharply 743.88% escalates dramatically 2.18 1010% Hz. findings reveal a pronounced asymmetry shifter biased extremely low frequencies.

Язык: Английский

Процитировано

0