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| 2. |
- Turalchuk, Pavel, et al.
(författare)
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Electrically tunable bulk acoustic filters with induced piezoelectric effect in BSTO film
- 2008
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Ingår i: 38th European Microwave Conference, EuMC 2008; Amsterdam; Netherlands; 27 October 2008 through 31 October 2008. - 9782874870064 ; , s. 1695-1698
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Konferensbidrag (refereegranskat)abstract
- In this paper we discuss a potential realizability of a tunable bulk acoustic filter based on BSTO film for microwave applications. The estimation of characteristics of the tunable TFBAR was done by processing the experimental data obtained for the BSTO resonator using the model of the induced piezoelectric effect. The third-order tunable TFBAR filter was designed. The necessary set of the acoustic and electric parameters of the tunable ferroelectric based TFBAR was proclaimed. The 10% tunability of the TFBAR filter pass band was estimated by a simulation. The simulated characteristics were obtained taking into consideration a real structure of the BSTO based resonators (electrodes and acoustic mirror).
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| 3. |
- Vendik, Irina, et al.
(författare)
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CAD Model for Microstrips on r-cut Sapphire Substrates
- 1994
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Ingår i: International Journal of Microwave and Millimeter-Wave Computer-Aided Engineering. - : Wiley. - 1050-1827 .- 1522-6301. ; 4:4, s. 374-383
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Tidskriftsartikel (refereegranskat)abstract
- Simple and correct formulas are derived for calculation of an effective isotropic dielectric constant, which characterizes the wave propagation in microstrip lines on anisotropic substrates made of r-cut sapphire crystals. The r-plane is extensively used for epitaxial growth of high-Tc superconductor YBa2Cu3O7 films as applied to microwave integrated circuits. In contradistinction to previous models developed for z-cut sapphire, the nondiagonal dielectric permittivity tensor of r-cut sapphire is used. The effective dielectric constant of a microstrip line on r-cut sapphire substrate is found as a function of the strip-line geometry and the orientation of the crystallographic axes with respect to the symmetry plane of the microstrip line
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| 4. |
- Vendik, Irina, et al.
(författare)
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Effective Dielectric Permittivity of r-Cut Sapphire Microstrip
- 1994
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Ingår i: Microwave Conference, 1994. 24th European. ; 1, s. 395 - 400
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Konferensbidrag (refereegranskat)abstract
- The effective dielectric constant of a microstrip is given as a function of the strip geometry and its orientation on the surface of the substrate. An "isotropized" dielectric constant is inroduced which can be used in commercial microwave software for simulation of r-cut sapphire substrate based micrstrip devices. Experimental velification of the analysis is also given.
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| 5. |
- Vendik, Irina, et al.
(författare)
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Full-wave analysis of fundamental modes of a multicoupled strip line with ferroelectric film
- 2005
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Ingår i: Technical Physics Letters. - : Pleiades Publishing Ltd. - 1090-6533 .- 1063-7850. ; 31:1, s. 68-71
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Tidskriftsartikel (refereegranskat)abstract
- The properties of a multicoupled microstrip line (MSL) with a thin control ferroelectric layer have been analyzed in terms of a full-wave model based on the method of moments in spectral domain. The Q values for all fundamental modes and their contributions to MSL losses are determined. It is established that various fundamental modes in multicoupled MSLs are characterized by significantly different Q values. The proposed method has been applied to the analysis of characteristics of an MSL-based ferroelectric microwave phase shifter. The figure of merit F of the phase shifter has been calculated for each fundamental mode. The results of analysis lead to a conclusion that, by exciting a fixed mode characterized by the maximum Q value, it is possible to obtain an MSL-based phase shifter possessing the optimum F at a minimum necessary level of the control voltage. © 2005 Pleiades Publishing, Inc.
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| 6. |
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| 7. |
- Vendik, Irina, et al.
(författare)
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Modeling tunable bulk acoustic resonators based on induced piezoelectric effect in BaTiO[sub 3] and Ba[sub 0.25]Sr[sub 0.75]TiO[sub 3] films
- 2008
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:1, s. 014107-1-6-
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Tidskriftsartikel (refereegranskat)abstract
- A model for tunable thin film bulk acoustic resonators (TFBARs) based on ferroelectric films is proposed. The model is based on electromechanical equations taking into account piezoelectric effect and electrostriction effect induced by the dc electric field. The dc field induced shift of the resonant frequency is explained by the high-order nonlinear effects in the ferroelectric material. The main contribution to the tunability of the resonant frequency under dc electric field can be attributed to electrostriction, which is nonlinear with respect to the mechanical deformation. It is shown that the upward or downward shift in the resonant frequency is given by the sign of the nonlinear component of the electrostriction tensor M. The model is verified by comparing the results with the measured microwave input impedance of BaTi O3 and Ba0.25 Sr0.75 Ti O3 based TFBARs. For a positive sign of the nonlinear coefficient of electrostriction M, the model predicts an upward shift of the resonant frequencies (resonance and antiresonance) under dc biasing in case of the TFBAR based on BaTi O3, whereas a negative sign of the nonlinear coefficient of electrostriction M predicts downward shift of the resonant frequencies for TFBAR based on Ba0.25 Sr0.75 Ti O3 films. © 2008 American Institute of Physics.
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| 8. |
- Gevorgian, Spartak, 1948, et al.
(författare)
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Electrically Controlled HTSC/Ferroelectric Coplanar Waveguide
- 1994
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Ingår i: Microwave and Optical Technology Letters. - : Institution of Engineering and Technology (IET). - 1098-2760 .- 0895-2477. ; 141:6, s. 501 - 503
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that in an integrated YBa2Cu3O7SrTiO3 structure coplanar waveguide (CPW) electrical control of microwave propagation characteristics is possible. Microwave losses of less than 0.2 dB/cm at 10 GHz can be achieved at liquid nitrogen temperatures, provided ferroelectric films with perfect crystalline structures are used. Electrically controlled changes in effective dielectric permittivity of more than 40% are predicted at 77 K and 10 GHz. Sections of these CPWs can be used in electrically controlled phase shifters and resonators.
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| 9. |
- Gevorgian, Spartak, 1948, et al.
(författare)
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Microwave Performance of a HTSC Coplanar-Strip Waveguide
- 1994
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Ingår i: Microwave Performance of a HTSC Coplanar-Strip Waveguide. ; 1, s. 505 - 510
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Konferensbidrag (refereegranskat)abstract
- Download CitationEmailPrintRequest PermissionsAnalytical expressions for current distribution, losses in superconducting strips, effective dielectric constant and the quality factor of HTSC coplanar-strip waveguides are given
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| 10. |
- Gevorgian, Spartak, 1948, et al.
(författare)
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Tunable ferroelectric resonator arrangement
- 2006
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Patent (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates to a tunable resonating arrangement comprising a resonator apparatus (10), input/output coupling (4) means for coupling electromagnetic energy into/out of the resonator apparatus, and a tuning device (3) for application of a biasing voltage/electric field to the resonator apparatus. The resonator apparatus comprises a first resonator (1) and a second resonator (2). Said first resonator is non-tunable and said second resonator is tunable and comprises a ferroelectric substrate (21). Said first and second resonators are separated by a ground plane (13) which is common for said first and second resonators, and coupling means (5) are provided for providing coupling between said first and second resonators. For tuning of the resonator apparatus, the biasing voltage/electric field is applied to the second resonator (2)
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