An Application of a Low-Loss MOD-Made BST Film Developed Especially with PLD Initial Nucleation Layer to a 20 GHz Tunable Phase Shifter

2004 ◽  
Vol 833 ◽  
Author(s):  
Minoru Noda ◽  
Daniel Popovici ◽  
Masanori Okuyama ◽  
Yoshinobu Sasaki ◽  
Makio Komaru
Keyword(s):  
Thin Films ◽  
Phase Shift ◽  
Phase Shifter ◽  
Coplanar Waveguide ◽  
Final Thickness ◽  
Nucleation Layer ◽  
Differential Phase Shift ◽  
Bst Thin Films ◽  
Main Layer ◽  
Initial Layer

ABSTRACTBarium Strontium Titanate (BST) thin films have been deposited on (100)-oriented MgO substrate by combining preparation of initial layer by Pulsed Laser Deposition and main layer by Metal-Organic-Decomposition method. Films with an initial layer of 20, 30 and 40 nm thickness and final thickness of 400, 650 and 800 nm have been obtained. Physical and dielectric properties of the BST thin films have been characterized from the viewpoint of frequency-agile micro and millimeter wave circuit applications. The results reveal that Ba0.6Sr0.4TiO3 thin films have a good crystallinity with characteristic orientation that is affected by the deposition conditions of the initial layer. Interdigital capacitor with a gap of 10 μm has been characterized and the dielectric loss and tunability are as low as 0.002 to 0.004 and 12%, respectively, at frequency of 1 MHz for the applied voltage from -/+40V to +/-40V. At microwave frequencies, classical coplanar waveguide lines formed on BST/(100)MgO were investigated. A differential phase shift of 18 degree was obtained at 20 GHz with insertion loss of about −2 dB at 60 V for Au/Cr interconnection. Finally, a 3-stage LC-ladder-type phase shifter with variable capacitors of BST thin film has been fabricated considering the experimental results obtained for the coplanar waveguide lines and a maximum phase shift of 40 degrees is obtained at 20 GHz at 60 V.

Width and Gap Dependent Performance of Ferroelectric Coplanar Waveguide Phase Shifter Based on Ba1-xSrxTiO3 Thin Films

2004 ◽  
Vol 833 ◽  
Author(s):  
Seung Eon Moon ◽  
Eun-Kyoung Kim ◽  
Min Hwan Kwak ◽  
Young-Tae Kim ◽  
Han-Cheol Ryu ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Shifter ◽  
Layer Structure ◽  
Coplanar Waveguide ◽  
Microwave Dielectric Properties ◽  
Bias Field ◽  
Geometrical Factor ◽  
Scattering Parameter ◽  
Differential Phase Shift ◽  
Dc Bias

ABSTRACT(001) oriented (Ba, Sr)TiO3 (BST) thin films were deposited on MgO (001) single crystal substrates by the pulsed laser deposition method. Structural properties of BST films were investigated using X-ray diffractometer. Coplanar waveguide (CPW) device based on BST/MgO layer structure was fabricated by dc sputtering deposition, photolithography and etching process. To study the geometrical factor dependent microwave performance of the CPW phase shifter based on (001) oriented BST film, the CPW devices having various gap and width were fabricated. The microwave dielectric properties of BST CPW phase shifter devices were examined by calculating the scattering parameter obtained using a HP 8510C vector network analyzer with the frequency range 0.5 ∼ 20 GHz at room temperature under the dc bias field of 0 ∼ 40V. The measured return loss and insertion loss at 10 GHz with no dc bias were about -12 ∼ -4 dB and -14 ∼ -3 dB, respectively, which mainly depended on the impedances of the CPW transmission lines. The measured differential phase shift values were about 20 ° ∼ 140 ° at 10 GHz with 40 V dc bias variations, which depended on the gap size.

An S-Band Reflection-Type Phase Shifter - A Design Example Using Ferroelectrics

2002 ◽  
Vol 720 ◽  
Author(s):  
Dongsu Kim ◽  
Yoonsu Choi ◽  
Mark G. Allen ◽  
J. Stevenson Kenney ◽  
David W. Stollberg ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Shift ◽  
Bias Voltage ◽  
Wireless Lan ◽  
Phase Shifter ◽  
Smart Antenna ◽  
Center Frequency ◽  
Voltage Range ◽  
Bst Thin Films ◽  
Type Phase

AbstractOne of the challenges faced in using ferroelectrics in high frequency devices is how to effectively use the material in a circuit design. A compact reflection-type phase shifter fabricated on sapphire substrates coated with ferroelectric barium strontium titanate (BST) thin-films has been built which shows the promise of using BST thin films in the design of tunable microwave devices. The phase shifter, fabricated as one monolithic assembly, consists of a 3dB coupler, meandered line inductors and tunable interdigital capacitors. A continuously variable phase shift range of more than 100° using the branch-line coupler was obtained at a center frequency of 2.95 GHz, and more than 90° phase shift over 200 MHz bandwidth with a bias voltage range from 0 V to 175 V. The phase shifter using the Lange coupler has over 700 MHz bandwidth centered at 2.2 GHz with a phase shift of more than 90° and an insertion loss less than 2 dB and return loss of greater than 14 dB, over a bias voltage range from 0 V to 160 V. The loss of the BST phase shifter presented in this work is on the order of other commercially available RF front-end components, such as bandpass filters and RF switches. This holds promise for the practical realization of smart antenna systems in cellular handsets and wireless LAN cards.

Design & Modeling of 6-Bit Low Loss Ka Band Distributed MEMS Phase Shifter on GaAs

2011 ◽  
Vol 403-408 ◽  
pp. 4179-4183
Author(s):  
Anesh K. Sharma ◽  
Ashu K. Gautam ◽  
D.V.K. Sastry ◽  
S.G. Singh
Keyword(s):  
Phase Shift ◽  
Insertion Loss ◽  
Phase Shifter ◽  
Structural Parameters ◽  
Coplanar Waveguide ◽  
Actuation Voltage ◽  
Ka Band ◽  
Rf Systems ◽  
Total Phase ◽  
Digital Phase Shifter

This paper presents the design & modeling of distributed MEMS phase shifter for Ka band RF systems. The phase shift can be achieved by periodically placing the MEMS bridge variable capacitors as per Bragg frequency criteria on coplanar waveguide (CPW) using GaAs substrate. The EM & electromechanical simulation are carried out with various structural parameters to optimize the designs. The novelties like low insertion loss, low actuation voltage with distributed actuation pads & separate DC and RF are used to make the design unique. The EM simulations are carried out with HFSS and an insertion loss of -3.49 dB at 36GHz for a total Phase shift of 360 deg. was achieved with return loss of - 20.6 dB over a frequency band 34-38 GHz. The electromechanical simulations are carried to achieve the low actuation voltage of 10.3V. The significance of this study is the realization of the digital phase shifter through DMTL approach.

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.

scholarly journals Rethinking Figure-of-Merits of Liquid Crystals Shielded Coplanar Waveguide Phase Shifters at 60 GHz

J ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 444-451 ◽  
Author(s):  
Jinfeng Li
Keyword(s):  
Liquid Crystals ◽  
Insertion Loss ◽  
Phase Shifter ◽  
Coplanar Waveguide ◽  
Volume Ratio ◽  
Phase Shifters ◽  
60 Ghz ◽  
Two Phase ◽  
Differential Phase Shift ◽  
Millimetre Wave

The demand for reconfigurable millimetre-wave (mm-Wave) components based on highly anisotropic liquid crystals (LC) is higher than ever before for the UK and worldwide. In this work, 60 GHz investigation on a bespoke shielded coplanar waveguide (SCPW) phase shifter structure filled with 16 types of microwave-enabled nematic LCs respectively indicates that the patterns of the device’s figure-of-merit (FoM, defined as the ratio of maximum differential phase shift to maximum insertion loss) reshuffle from those of the characterised LC materials’ FoM (defined as the ratio of tunability to maximum dissipation factor). To be more specific, GT7-29001- and MDA-03-2838-based phase shifters exhibit the highest FoM for devices, outperforming phase shifters based on GT5-28004 and TUD-566 with the highest FoM for materials. Such a mismatch between the device’s FoM and LC’s FoM implies a nonlinearly perturbed wave-occupied volume ratio effect. Furthermore, the relationship between insertion loss and the effective delay line length is nonlinear, as evidenced by measurement results of two phase shifters (0–π and 0–2π, respectively). Such nonlinearities complicate the established FoM metrics and potentially lead to a renewed interest in the selection and material synthesis of LCs to optimise reconfigurable mmWave devices, and promote their technological exploitation in phased array systems targeting demanding applications such as inter-satellite links and satellite internet.

Process Induced Modification of the High Frequency Dielectric Behavior of (100) Textured BaxSr1−xTiO3 (x = 0.5 and 0.6) Thin Films

2001 ◽  
Vol 688 ◽  
Author(s):  
S.B. Majumder ◽  
M. Jain ◽  
A. Martinez ◽  
R.S. Katiyar ◽  
E.R. Fachini ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Shift ◽  
Insertion Loss ◽  
Phase Shifter ◽  
Annealing Temperature ◽  
Dielectric Breakdown ◽  
Dielectric Behavior ◽  
Phase Shifters ◽  
Dielectric Devices

AbstractParaelectric BaxSr1−xTiO3 (BST) (x = 0.5 and 0.6) thin films are attractive candidates for the fabrication of various microwave dielectric devices including phase shifters, resonators, filters, oscillators etc. In the present work we have studied the effect of annealing temperature and ambient on the epitaxial quality, surface morphology, dielectric, and phase shifter characteristics of BST thin films deposited on LaAlO3 substrates. The epitaxial quality of the film was markedly improved as the annealing temperature was increased from 1050 to 1100°C. The degree of phase shift increased from 221 to 328° (measured at 14.5 GHz applying a field of 30V/μm) with the improvement of the epitaxial quality of the film. The insertion loss was also increased with the increase in annealing temperature and therefore the effective phase shifter κ factor (defined by the ratio of the degree of phase shift and insertion loss) remained low (∼30°/dB), while annealing these films in N2 ambient significantly reduced the insertion loss, their dielectric breakdown was observed at relatively lower applied voltage as compared to air and oxygen annealed films. The observed electrical behavior was correlated with the composition, chemical state of the constituents and epitaxial quality of the films synthesized under different annealing conditions.

Investigations on Sol-Gel Derived Ba0.5Sr0.5Ti1-δMnδO3 (δ = 0.0 to 5.0 at%) Thin Films for Phase Shifter Applications

2002 ◽  
Vol 720 ◽  
Author(s):  
R.S. Katiyar ◽  
M. Jain ◽  
S.B. Majumder ◽  
R.R. Romanofsky ◽  
F.W. van Keuls ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Phase Shift ◽  
Surface Morphology ◽  
Phase Shifter ◽  
Sol Gel ◽  
Bias Field ◽  
Mn Doping ◽  
First Order Phase Transition ◽  
Mn Doped

AbstractHighly (100) oriented Ba0.5Sr0.5Ti1-δMnδO3 thin films were deposited on (100) LaAlO3 (LAO) substrate by sol-gel technique. We have studied systematically the effect of Mn doping on the degree of texturing, surface morphology, dielectric properties and phase transition behavior of barium strontium titanate (BST) thin films. Up to 3 at % Mn doping the degree of (100) texturing and grain size of BST (50/50) thin films were markedly improved, which led to an increased tunability from 29% (undoped) to 39% (3 at % Mn doped); measured at 1 MHz and 2.34V/mm bias field. The transition and Curie-Weiss temperatures of BST (50/50) thin films were found to be about 266 K and 185 K respectively, which confirmed the first order phase transition in the films. The variation of transition temperatures as a function of Mn doping contents in BST (50/50) thin films were influenced by the variation of stress state and surface morphology modifications induced by Mn doping. The bias field dependence of the dielectric constant and loss tangents of undoped and Mn doped films were analyzed in terms of a model based on Devonshire theory. Phase shift measurements showed that the degree of phase shift increases from 239° to 337° with 0 to 3 at% Mn doping. The insertion loss also increases from 5.4 dB (undoped) to 9.9 dB (3 at % Mn doped) with doping content so that there is no effective improvement in the k factor, which remains in the range of 33 - 44°/dB. Modification in surface morphology and film stoichiometry induced by Mn doping is thought to play significant role in observed phase shifter characteristics.

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