Measurement of Dielectric Properties of Nematic Liquid Crystals at Millimeter Wavelength

Variable Temperature Broadband Microwave and Millimeter-Wave Characterization of Electrochromic (WO3/LiNbO3/NiO) Thin Films

“…Furthermore, it should be noted that the calculation of the cosh function in Eq. (3) involves the squareroot and complex natural logarithm functions which require further unwrapping of the imaginary part as well as the correction of the sign of the real part [3], [13] in order to properly obtain β and α, respectively.…”

“…1 (b) can be obtained using the measured complex propagation constant; εeff = (γ/γ0) 2 [20]. Here, γ0 = ω/c is the free space wave number and γ can be obtained from (3). The effective permittivity is interpreted as the permittivity of a homogeneous medium that equivalently replaces the air, conducting layers and the dielectric material [20].…”

Influence of rubbing-alignment on microwave modulation induced by liquid crystal

“…In calculations, the material parameters of the nematic liquid crystal E7 are shown in Table I. 16 The thickness of the LC cell is 10µm, and the frequency of microwave is f = 60 GHz. Rubbing substrate can cause the liquid crystal molecules on substrate surface to orientate along the different pre-tilt and pre-twisted angles.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] The microwave modulation property of liquid crystal is based on the fact discovered by K. C. Lim et al 14 that many liquid crystal materials retain considerable anisotropy of the permittivity and optical birefringence in microwave bands of electromagnetic radiation which has ever been reported in later literatures. [15][16][17][18] Then, Masaki Tanaka et al and Hideo Fujikake et al have manufactured the liquid crystal phase shifters by controlling the distribution of director in cell using the grating electrode structure 1 and the photopolymerization induced phase separation technology, 3 respectively. Meanwhile, the tunable liquid crystal microwave prism with a stack-layered structure is prepared using wedge-shaped metal substrates and nematic LC with a positive dielectric anisotropy.…”

Effective dielectric constant of top grounded coplanar waveguide on liquid crystal superstrate

“…Microstrip antennas can be divided into two basic types by structure, namely microstrip patch antenna [1][2][3] and microstrip slot antenna [4,5]. Many communication and sensor systems …”