Tunable inverted-microstrip phase shifter device using nematic liquid crystals

Technological evolution and performances improvements of a tunable phase‐shifter using liquid crystal

“…The average FOM reaches 18°/dB for a 20-V control voltage. These values are well situated in comparison with those reported by others authors [9].…”

“…Average FOM reaches 14°/dB for a 20-V control voltage. This value is lower than that given by the first device, but better than those reported by others [9]. Accuracy of the lines' dimensions will contribute to improve the signal transmission S 21 and hence improve the FOM.…”

“…Both structures need a rigid dielectric substrate to hold the conductor line; we used polytetrafluoroethylene (PTFE) with r ϭ 2.2. This weak relative permittivity, in comparison with others structures [7][8][9], is of great interest because electric-field lines are less concentrated in PTFE than in LC, whose dielectric permittivity is higher ( r between 2.7 and 2.9 for K15 liquid crystal). Figure 2 shows the first device topology.…”

High-frequency signal processing using magnetic layered structures

“…In a microstrip structure the substrate is shielded from the device by the ground plane and one measures the full change in e of the liquid crystal. Some microstrip phase shifters have already been investigated in the range 10-20 GHz [52].…”

Tunable hairpin resonator based on liquid crystal

“…Due to their light weight, low cost, compact size, and negligible power consumption, tunable devices based on liquid crystal are receiving an increased attention, in particular in view of their utilization in reconfigurable circuits and antennas. Various versions of tunable microwave components with liquid crystals have been proposed, for example liquid crystal phase shifter [1], variable delay-line [2], reflectarray antenna [3], etc. most of them use open transmission line or patch structure.…”