Liquid crystal phase shifter for Terahertz frequencies with quasi-orthogonal electrical bias field

Continuously reconfigurable 100 GHz band phased array antenna with improved response time using a microfiber/liquid crystal composite

“…As elucidated earlier, in the case of HF devices, this is a mandatory condition for achieving rise times (a few ms or more) comparable to optical devices; or we need to compromise with rise times measured in seconds, even tens of seconds, as observed in previous reports. 15,24,26,[31][32][33] A simple method to reduce voltage requirements while preserving rapid response times involves extending the line length. However, this method leads to an increase in the transmission loss for the phase shifter, resulting in a decrease in the antenna gain.…”

Unveiling Low THz Dynamics of Liquid Crystals: Identification of Intermolecular Interaction among Intramolecular Modes

“…The steady advancements in tabletop THz sources led to intense ongoing research on possible devices and materials to modulate and control THz waves in a similar manner. Nematic LCs were already demonstrated to be low-loss and tunable birefringent materials for THz-wave plates and phase shifters. − However, their applicability is still limited because of the counteracting combination of birefringence and necessary thickness of the medium. , The long THz wavelengths (3000–30 μm) require considerably larger LC thicknesses to obtain a reasonable phase shift, such that losses become no longer negligible. To design new switching devices or guide molecular design targeting such THz performances, we need a detailed understanding of the microscopic properties of the LC in the THz range.…”

“…Nematic LCs were already demonstrated to be low-loss and tunable birefringent materials for THz-wave plates and phase shifters. 5 − 8 However, their applicability is still limited because of the counteracting combination of birefringence and necessary thickness of the medium. 9 , 10 The long THz wavelengths (3000–30 μm) require considerably larger LC thicknesses to obtain a reasonable phase shift, such that losses become no longer negligible.…”

Optimization of the electrospun-aligned microfiber composite with liquid crystal for terahertz wave variable phase shifters

“…[12][13][14][15][16] Some studies that used LCs as materials for the THz wave phase shifters have been reported. [17][18][19][20][21] Unlike optical applications, where the LC response time must be met with an instantaneous switching of millisecond order as a top priority, phase-shift applications require a balance among four major factors: switching time, phase change, operating voltage, and propagation loss that correspond to the response time, birefringence, threshold voltage, and natural loss of LC materials, respectively. Previous studies have reported that THz wave phase shifters using LC have either a tiny phase change 17) or a excessively long decay time due to the thick LC layer of several hundreds of micrometers or more.…”

“…Previous studies have reported that THz wave phase shifters using LC have either a tiny phase change 17) or a excessively long decay time due to the thick LC layer of several hundreds of micrometers or more. [18][19][20][21] As effective methods for improving the decay time, polymerstabilized LC (PSLC) [22][23][24][25][26][27][28][29][30] and nanofiber (NF)/LC composite 31,32) have been employed. In the PSLC, reactive bifunctional monomers with a small amount (<10 wt%) are mixed into the LC and crosslinked to each other after polymerization.…”