Liquid crystal millimeter wave electronic phase shifter

In this paper we investigate the temperature dependent behavior of a liquid crystal (LC) loaded tunable dielectric image guide (DIG) phase shifter at millimeter-wave frequencies from 80 GHz to 110 GHz for future high data rate communications. The adhesive, necessary for precise fabrication, is analyzed before temperature dependent behavior of the component is shown, using the nematic LC-mixture GT7-29001. The temperature characterization is conducted by changing the temperature of the LC DIG’s ground plane between −10∘C and 80 ∘C. The orientation of the LC molecules, and therefore the effective macroscopic relative permittivity of the DIG, is changed by inserting the temperature setup in a fixture with rotatable magnets. Temperature independent matching can be observed, while the insertion loss gradually increases with temperature for both highest and lowest permittivity of the LC. At 80 ∘C the insertion loss is up to 1.3dB higher and at −10∘C it is 0.6dB lower than the insertion loss present at 20 ∘C. In addition, the achievable differential phase is reduced with increasing temperature. The impact of molecule alignment to this reduction is shown for the phase shifter and an estimated 85% of the anisotropy is still usable with an LC DIG phase shifter when increasing the temperature from 20 ∘C to 80 ∘C. Higher reduction of differential phase is present at higher frequencies as the electrical length of the phase shifter increases. A maximum difference in differential phase of 72∘ is present at 110 GHz, when increasing the temperature from 20 ∘C to 80 ∘C. Nevertheless, a well predictable, quasi-linear behavior can be observed at the covered temperature range, highlighting the potential of LC-based dielectric components at millimeter wave frequencies.

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Liquid crystal enabled substrate integrated waveguide variable phase shifter for millimeter-wave application at 60ghz and beyond

2015 IEEE MTT-S International Microwave Symposium ◽

10.1109/mwsym.2015.7166961 ◽

2015 ◽

Author(s):

Kuangda Wang ◽

Ke Wu

Keyword(s):

Liquid Crystal ◽

Millimeter Wave ◽

Phase Shifter ◽

Substrate Integrated Waveguide ◽

Variable Phase

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Improvement of Phase-Shifting Properties in Coplanar Waveguide-Type Liquid Crystal Millimeter-Wave Phase Shifter by Introducing a Resonant Phenomenon

Japanese Journal of Applied Physics ◽

10.1143/jjap.47.8483 ◽

2008 ◽

Vol 47 (11) ◽

pp. 8483-8486 ◽

Cited By ~ 14

Author(s):

Toshiaki Nose ◽

Susumu Yanagihara ◽

Yukiko Sato ◽

Ryota Ito ◽

Michinori Honma

Keyword(s):

Liquid Crystal ◽

Millimeter Wave ◽

Phase Shifter ◽

Coplanar Waveguide ◽

Phase Shifting ◽

Resonant Phenomenon ◽

Wave Phase ◽

Waveguide Type

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Electronic Phase Shifter for Millimeter-Wave Semiconductor Dielectric Integrated Circuits

IEEE Transactions on Microwave Theory and Techniques ◽

10.1109/tmtt.1974.1128240 ◽

1974 ◽

Vol 22 (4) ◽

pp. 411-417 ◽

Cited By ~ 61

Author(s):

H. Jacobs ◽

M.M. Chrepta

Keyword(s):

Integrated Circuits ◽

Millimeter Wave ◽

Phase Shifter ◽

Electronic Phase

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Fundamental performance of liquid crystal millimeter-wave phase shifter using negative dielectric anisotropic material

2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz) ◽

10.1109/irmmw-thz.2014.6956283 ◽

2014 ◽

Author(s):

Toshiaki Nose ◽

Masashi Nagasawa ◽

Takumi Komuro ◽

Takayuki Sasamori ◽

Yoji Isota ◽

...

Keyword(s):

Liquid Crystal ◽

Millimeter Wave ◽

Anisotropic Material ◽

Phase Shifter ◽

Wave Phase

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Potential of Liquid-Crystal Materials for Millimeter-Wave Application

Applied Sciences ◽

10.3390/app8122544 ◽

2018 ◽

Vol 8 (12) ◽

pp. 2544 ◽

Cited By ~ 2

Author(s):

Toshiaki Nose ◽

Ryota Ito ◽

Michinori Honma

Keyword(s):

Liquid Crystal ◽

Millimeter Wave ◽

Microstrip Line ◽

Phase Shifter ◽

Substrate Surface ◽

Antenna System ◽

Phase Shifters ◽

Phased Array Antenna ◽

Electric Circuits ◽

Line Type

In this study, we reviewed three topics regarding the application of liquid-crystal (LC) materials to millimeter-wave (MMW) devices. It is essential to develop useful measurement methods for refractive indices of LC materials in the MMW region. Herein, a novel measurement method using optical short is demonstrated using a Si semiconductor substrate. There are two approaches to develop MMW LC devices. One is the quasi-optical approach, which involves scaling up the optical components, and the other approach involves integrating the LC materials into high-frequency electric circuits. A three-dimensional (3D) printer is used to fabricate the Fresnel lens, which is a typical quasi-optical device useful in the MMW region, where we can develop the tunable lens by introducing LC materials. A planar-type MMW waveguide is advantageous for integrating the LC materials to develop LC MMW devices using the second approach. We investigated a useful microstrip-line-type LC phase shifter by developing a novel conversion circuit to introduce the LC material onto the dielectric substrate surface. A phase shifter is an important MMW component that is used to attain a phased array antenna system, and a minimal twin antenna array is demonstrated using the microstrip-line-type LC phase shifters.

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Microwave Liquid Crystal Enabling Technology for Electronically Steerable Antennas in SATCOM and 5G Millimeter-Wave Systems

Crystals ◽

10.3390/cryst10060514 ◽

2020 ◽

Vol 10 (6) ◽

pp. 514 ◽

Cited By ~ 3

Author(s):

Rolf Jakoby ◽

Alexander Gaebler ◽

Christian Weickhmann

Keyword(s):

Liquid Crystal ◽

Phase Shift ◽

Millimeter Wave ◽

Phase Shifter ◽

Beam Steering ◽

Phase Shifters ◽

Worst Case ◽

Differential Phase Shift ◽

Digital Architecture ◽

Differential Phase

Future satellite platforms and 5G millimeter wave systems require Electronically Steerable Antennas (ESAs), which can be enabled by Microwave Liquid Crystal (MLC) technology. This paper reviews some fundamentals and the progress of microwave LCs concerning its performance metric, and it also reviews the MLC technology to deploy phase shifters in different topologies, starting from well-known toward innovative concepts with the newest results. Two of these phase shifter topologies are dedicated for implementation in array antennas: (1) wideband, high-performance metallic waveguide phase shifters to plug into a waveguide horn array for a relay satellite in geostationary orbit to track low Earth orbit satellites with maximum phase change rates of 5.1°/s to 45.4°/s, depending on the applied voltages, and (2) low-profile planar delay-line phase shifter stacks with very thin integrated MLC varactors for fast tuning, which are assembled into a multi-stack, flat-panel, beam-steering phased array, being able to scan the beam from −60° to +60° in about 10 ms. The loaded-line phase shifters have an insertion loss of about 3 dB at 30 GHz for a 400° differential phase shift and a figure-of-merit (FoM) > 120°/dB over a bandwidth of about 2.5 GHz. The critical switch-off response time to change the orientation of the microwave LCs from parallel to perpendicular with respect to the RF field (worst case), which corresponds to the time for 90 to 10% decay in the differential phase shift, is in the range of 30 ms for a LC layer height of about 4 µm. These MLC phase shifter stacks are fabricated in a standard Liquid Crystal Display (LCD) process for manufacturing low-cost large-scale ESAs, featuring single- and multiple-beam steering with very low power consumption, high linearity, and high power-handling capability. With a modular concept and hybrid analog/digital architecture, these smart antennas are flexible in size to meet the specific requirements for operating in satellite ground and user terminals, but also in 5G mm-wave systems.

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