Microwave Liquid Crystal Technology

Maune, Holger

doi:10.3390/cryst10080716

Cited by 13 publications

(11 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The properties of the three types of LCs are listed in Table 1. During the measurement, DC (0 Hz) and square wave voltages from 10 Hz to 10 kHz are applied between the electrode and NaM in the range of 0 V to 20 V in steps of 1 V. The electric characteristics of the tuneable phase shifters remain nearly constant for bias voltages higher than 10 V. An important parameter used for quantifying the RF performance of a phase shifter is the frequency-related FoM, which is defined by the ratio of the maximum phase shift over the highest IL among the two extreme LC alignment cases [17]:…”

Section: B Slow-wave Phase Shifter With Lcmentioning

confidence: 99%

See 1 more Smart Citation

Fast and Miniaturized Phase Shifter With Excellent Figure of Merit Based on Liquid Crystal and Nanowire-Filled Membrane Technologies

et al. 2022

Self Cite

View full text Add to dashboard Cite

This paper presents a highly miniaturized tuneable microstrip line phase shifter for 5 GHz to 67 GHz. The design takes advantage of the microstrip topology by substituting the ground plane by a metallic-nanowire-filled porous alumina membrane (NaM). This leads to a slow-wave (SW) effect of the transmission line; thus, the transmission line can be physically compact while maintaining its electric length. By applying a liquid crystal (LC) with its anisotropic permittivity as substrate between the transmission line and the NaM, a tuneable microstrip line phase shifter is realized. Three demonstrators are identically fabricated filled with different types of high-performance microwave LCs from three generations (GT3-23001, GT5-26001 and GT7-29001). The measurement results show good matching in a 50 system with reflection less than −10 dB over a wide frequency range. These demonstrators are able to reach a maximum figure of merit (FoM) of 41 • /dB, 48 • /dB, and 70 • /dB for different LCs (GT3-23001, GT5-26001 and GT7-29001, respectively). In addition, experiments show that all three LCs should be biased with square wave voltage at approximately 1 kHz to achieve maximum tuneability and response speed. The achieved response times with GT3-23001, GT5-26001 and GT7-29001 are 116 ms, 613 ms, and 125 ms, respectively, which are much faster than other reported LC phase shifter implementations. Large-signal analysis shows that these implementations have high linearity with third-order interception (IP3) points of approximately 60 dBm and a power handling capability of 25 dBm.

show abstract

Section: B Slow-wave Phase Shifter With Lcmentioning

confidence: 99%

“…The three generations of LC mixtures used in this paper are in the nematic phase, in which the LC is considered a uniaxial anisotropic material because of its rod-like molecules [17], [18]. When electromagnetic waves pass through the LC, it exhibits different permittivities, depending on the orientation of the LC molecules to the RF field.…”

mentioning

confidence: 99%

Fast and Miniaturized Phase Shifter With Excellent Figure of Merit Based on Liquid Crystal and Nanowire-Filled Membrane Technologies

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the mm-Wave regime, the anisotropic behaviour of LC is exploited, taking advantage of the variable effective permittivity of the material. Particularly, thermotropic calamitic nematic LCs are used as mixtures for microwave applications, and the anisotropy present in the nematic phase is used for electrically tunable RF circuit/devices [80].…”

Section: ) Liquid Crystalmentioning

confidence: 99%

Pattern Reconfigurable Antennas at Millimeter-Wave Frequencies: A Comprehensive Survey

et al. 2022

View full text Add to dashboard Cite

“…Liquid crystal is one of the most promising tunable materials for applications in the microwave range [25]. However, the study of the wave propagation in liquid-crystal-based periodic structures is a complex task due to the anisotropic and lossy nature of the material, accounted for by a non-diagonal permittivity tensor [26].…”

Section: Introductionmentioning

confidence: 99%

Dispersion Analysis of Periodic Structures in Anisotropic Media: Application to Liquid Crystals

Alex‐Amor

Palomares‐Caballero

Mesa

et al. 2022

IEEE Trans. Antennas Propagat.

View full text Add to dashboard Cite

This paper presents an efficient method to compute the dispersion diagram of periodic structures with generic anisotropic media. The method takes advantage of the ability of full-wave commercial simulators to deal with finite structures having anisotropic media. In particular, the proposed method opens new possibilities with respect to commercial eigenmode solvers: (i) anisotropic materials with non-diagonal permittivity and permeability tensors can be analyzed; (ii) the attenuation constant can easily be computed and lossy materials can be included in the simulation; (iii) unbounded and radiating structures such as leakywave antennas can be treated. In this work, the proposed method is particularized for the study of liquid crystals (LCs) in microwave and antenna devices. Since LCs show promising capabilities for the design of electronically reconfigurable elements, the dispersion properties of a great variety of LC-based configurations are analyzed, from canonical structures, such as waveguide and microstrip, to complex reconfigurable phase shifters in ridge gap-waveguide technology and leaky-wave antennas. Our results have been validated with previously reported works in the literature and with the Eigenmode solver of commercial software CST.

show abstract

Microwave Liquid Crystal Technology

Abstract: Information and communication technologies (ICT) are the foundation of growth and development in the modern global economy [...]

Cited by 13 publications

References 6 publications

Fast and Miniaturized Phase Shifter With Excellent Figure of Merit Based on Liquid Crystal and Nanowire-Filled Membrane Technologies

Fast and Miniaturized Phase Shifter With Excellent Figure of Merit Based on Liquid Crystal and Nanowire-Filled Membrane Technologies

Pattern Reconfigurable Antennas at Millimeter-Wave Frequencies: A Comprehensive Survey

Dispersion Analysis of Periodic Structures in Anisotropic Media: Application to Liquid Crystals

Contact Info

Product

Resources

About