Tunable liquid crystal reflectarray patch element

Hu, Wencheng; Ismail, M. Y.; Cahill, R.; Gamble, H.S.; Dickie, R.; Fusco, Vincent; Linton, D.; Rea, Simon; Grant, N.

doi:10.1049/el:20060571

Cited by 50 publications

(23 citation statements)

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“…1, is obtained by applying a low frequency AC voltage between the patch and the ground plane, to create a variable z-directed electrostatic field in the substrate region. As a result, the permittivity of the tunable substrate varies between two values e// (biased state) and e± (0 V state) and therefore the dielectric anisotropy is given by Ae eff = e// -e± [6]. Note that the effective dielectric constant is insensitive to the orientation of the electric field in the X Y plane, and therefore it is valid for any polarization and angle of incidence of the impinging wave.…”

Section: Design and Numerical Resultsmentioning

confidence: 99%

“…Waveguide simulator measurements have recently been used at X-band in a proof of concept study to demonstrate that dynamic phase control can be obtained by constructing a reflectarray on a thin layer of liquid crystals [6]. Moreover by employing data fitting to the experimental results, the loss tangent and permittivity values of three commercially available anisotropic specimens were obtained [8].…”

Section: Fabrication and Measurement Techniquementioning

confidence: 99%

See 1 more Smart Citation

Design and Measurement of Reconfigurable Millimeter Wave Reflectarray Cells With Nematic Liquid Crystal

Cahill

Encinar

et al. 2008

IEEE Trans. Antennas Propagat.

163

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Section: Design and Numerical Resultsmentioning

confidence: 99%

Section: Fabrication and Measurement Techniquementioning

confidence: 99%

Design and Measurement of Reconfigurable Millimeter Wave Reflectarray Cells With Nematic Liquid Crystal

Cahill

Encinar

et al. 2008

IEEE Trans. Antennas Propagat.

163

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“…Menzel has demonstrated designs that are reasonably compact, using polarizing grids as the subreflector element [20,21]. Liquid crystals have been used to implement reconfigurable functionality, since their dielectric characteristics are voltage-dependent [22,23]. Another technique is centered on using varactor diodes, as demonstrated by Hum et al [24].…”

Section: Reconfigurable Reflectarraysmentioning

confidence: 99%

Reflector and Lens Antennas

Preez

Sinha

2016

Millimeter-Wave Antennas: Configurations and Applications

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This chapter is subdivided into two sets of antennas that function on similar principles. While the reflector is known for shaping a beam in a particular direction (based on the location of a feed antenna) by using a reflecting aperture, a lens achieves a shaped beam by diffracting the signal from the source antenna.The use of reflector antennas can be traced back as far as the discovery of electromagnetic propagation in 1888. However, it was not until the explosion of radar development in World War II that the design process behind many familiar reflector shapes was developed.Following the years after World War II, reflector antennas were in high demand for applications such as long-distance satellite communications, radio astronomy, and increasingly sophisticated high-resolution radar systems. During this time, many of the analytical techniques regarding the optimization of the illumination of a reflector aperture in order to maximize gain, emerged. Reflector antennas are typically capable of providing extremely narrow beamwidths and higher gains than any other single-element configuration. Reflect arrays have also seen substantial development in the last two decades. As the name implies, this antenna is a combination of the most desirable characteristics offered by reflectors and array antennas.On the other hand, lens antennas have also been thoroughly investigated for millimeter-wave applications. A low profile and excellent beamforming capabilities make these antennas suitable for a number of applications (especially in automotive radar), and the development of substrate-integrated waveguide technology has been an important enabler in extending their operation into the millimeter region. Single Feed ReflectorsA parabolic surface (shown in Fig. 5.1) is most often used as a reflector, because it can produce a highly directional pencil beam with very low sidelobe levels. To avoid mechanical steering of the reflector itself (which in many cases can be quite

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“…Recently the use of nematic liquid crystals as a dielectric with electronically tunable permittivity has emerged as a technology suitable for continuous tuning of (sub)mm-wave and THz devices [9]. By applying an external field dynamic adjustment of the effective dielectric properties can be achieved [10], [11]. A waveguide-based liquid crystal polarizer was proposed in [12] as means to deliver continuous tuning of the polarization state between -90 o to 90 o and was demonstrated at Q-band.…”

Section: Introductionmentioning

confidence: 99%