scholarly journals Microwave Liquid Crystal Technology

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 355 ◽  
Author(s):  
Holger Maune ◽  
Matthias Jost ◽  
Roland Reese ◽  
Ersin Polat ◽  
Matthias Nickel ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Millimeter Wave ◽  
Antenna Arrays ◽  
High Performance ◽  
Beam Steering ◽  
Phase Shifters ◽  
Dielectric Waveguides ◽  
Microwave Components ◽  
Recent Developments ◽  
Rectangular Waveguides

Tunable Liquid Crystal (LC)-based microwave components are of increasing interest in academia and industry. Based on these components, numerous applications can be targeted such as tunable microwave filters and beam-steering antenna systems. With the commercialization of first LC-steered antennas for Ku-band e.g., by Kymeta and Alcan Systems, LC-based microwave components left early research stages behind. With the introduction of terrestrial 5G communications systems, moving to millimeter-wave communication, these systems can benefit from the unique properties of LC in terms of material quality. In this paper, we show recent developments in millimeter wave phase shifters for antenna arrays. The limits of classical high-performance metallic rectangular waveguides are clearly identified. A new implementation with dielectric waveguides is presented and compared to classic approaches.

scholarly journals Reconfigurable Millimeter-Wave Components Based on Liquid Crystal Technology for Smart Applications

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 346 ◽  
Author(s):  
Ersin Polat ◽  
Henning Tesmer ◽  
Roland Reese ◽  
Matthias Nickel ◽  
Dongwei Wang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Millimeter Wave ◽  
Beam Steering ◽  
Phase Shifters ◽  
Dielectric Waveguides ◽  
Promising Alternative ◽  
Single Antenna ◽  
W Band ◽  
Antenna Type ◽  
High Degree

This paper presents recent development of tunable microwave liquid crystal (LC) components in the lower millimeter wave (mmW) regime up to the W-band. With the utilization of increasing frequency, conventional metallic waveguide structures prove to be impractical for LC-based components. In particular, the integration of the electric bias network is extremely challenging. Therefore, dielectric waveguides are a promising alternative to conventional waveguides, since electrodes can be easily integrated in the open structure of dielectric waveguides. The numerous subcategories of dielectric waveguides offer a high degree of freedom in designing smart millimeter wave components such as tunable phase shifters, filters and steerable antennas. Recent research resulted in many different realizations, which are analyzed in this paper. The first demonstrators of phased array antennas with integrated LC-based phase shifters are reviewed and compared. In addition, beam steering with a single antenna type is shown. Furthermore, the possibility to realize tunable filters using LC-filled dielectric waveguides is demonstrated.

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

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 514 ◽  
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.

Double Dielectric Slab-Loaded Air-Filled SIW Phase Shifters for High-Performance Millimeter-Wave Integration

2016 ◽  
Vol 64 (9) ◽  
pp. 2833-2842 ◽  
Author(s):  
Frederic Parment ◽  
Anthony Ghiotto ◽  
Tan-Phu Vuong ◽  
Jean-Marc Duchamp ◽  
Ke Wu
Keyword(s):  
Millimeter Wave ◽  
High Performance ◽  
Phase Shifters ◽  
Dielectric Slab

scholarly journals Split Antenna Array in Millimeter Wave for Secure Vehicular Communication

2018 ◽  
Vol 173 ◽  
pp. 02024
Author(s):  
Shah Marjan ◽  
Lin Bai ◽  
Chao Han
Keyword(s):  
Millimeter Wave ◽  
Antenna Arrays ◽  
Physical Layer Security ◽  
Communication Systems ◽  
Physical Layer ◽  
Directional Antennas ◽  
Phase Shifters ◽  
Superior Performance ◽  
Artificial Noise ◽  
Vehicular Communication

The small carrier wavelength at millimeter wave (mm-wave) frequencies features a large number of co-located antennas. Wireless networks with directional antennas using beamforming at mm-wave also have potential to provide an enhanced security in the vehicular communication system. Large bandwidth of mm-wave can provide auto drive and safety linked functionalities, However, safety and efficiency of the vehicular transportation system can be jeopardized by many kinds of attacks by eavesdroppers, physical layer security can work as an extra layer of security for wireless communication systems. To secure communication in-between Vehicles, an Analog precoding based physical Layer technique for mm-wave vehicular communication systems is presented in the paper. The proposed technique works by exploiting large Antenna arrays at millimeter waves and provide a secure directional transmission with low power consuming phase shifters and single Radio Frequency Chain. Larger antennas arrays are split into two subsets, one for transmission of data and another for generating noise. The proposed technique offers improved coherent transmission at the legitimate receiver and by introducing artificial noise to the eavesdroppers at random directions. This outcome in low SNR for the eavesdroppers, hence hacking information becomes extremely difficult. Numerical and Simulation results show the superior performance of the proposed technique compared to traditional physical layer security technique and conventional array technique.

scholarly journals Potential of Liquid-Crystal Materials for Millimeter-Wave Application

2018 ◽  
Vol 8 (12) ◽  
pp. 2544 ◽  
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.

Millimeter Wave Solid State Devices

2000 ◽  
Vol 631 ◽  
Author(s):  
Steven A. Rosenau ◽  
Cheng Liang ◽  
Weikang Zhang ◽  
Bihe Deng ◽  
Weiying Li ◽  
...  
Keyword(s):  
Solid State ◽  
Millimeter Wave ◽  
Transmission Lines ◽  
High Speed ◽  
Beam Steering ◽  
Phase Shifters ◽  
Frequency Multiplier ◽  
Mems Switches ◽  
Solid State Devices ◽  
True Time

ABSTRACTExamples of novel solid state devices are presented, together with descriptions of their applicability to the diagnosis of laboratory, processing and fusion plasmas. GaAs varactor diodes can be arranged in large monolithic grid arrays, forming millimeter wave frequency multiplier based sources and high speed switches, or embedded in transmission lines to provide a true time delay for phased antenna array beam steering. Micro-electromechanical systems (MEMS) switches are exciting new devices with numerous applications, including low loss millimeter wave switches, phase shifters and mechanically tunable structures.

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