| 1. |
- Abadei, S., et al.
(författare)
-
DC field dependent properties of Na0.5K0.5NbO3/SiO2/Si structures at millimeter-wave frequencies
- 2001
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 78:13, s. 1900-1902
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Tidskriftsartikel (refereegranskat)abstract
- Dielectric properties of laser-ablated 0.5-mum-thick c-axis epitaxial Na0.5K0.5NbO3 films on high-resistivity (7.7 Omega cm) silicon SiO2/Si substrate are studied experimentally at frequencies up to 40 GHz. For measurements, planar 0.5-mum-thick gold electrodes (interdigital and straight slot) are photolithography defined on the top surface of Na0.5K0.5NbO3 films. The slot width between the electrodes is 2 or 4 mum. 13% capacitance change at 40 V dc bias and Q factor more than 15 are observed at 40 GHz, which makes the structure useful for applications in electrically tunable millimeter-wave devices.
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| 2. |
- Abadei, Saeed, 1961, et al.
(författare)
-
Low-frequency and microwave performances of laser-ablated epitaxialNa 0.5 K 0.5 NbO 3 films on high-resistivitySiO 2 /Si substrates
- 2002
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 91, s. 2267-
-
Tidskriftsartikel (refereegranskat)abstract
- The dielectric properties of laser-ablated 0.5-μm-thick c-axis epitaxialNa 0.5 K 0.5 NbO 3 (NKN) films on high-resistivity (>7.7 kΩ cm) siliconSiO 2 /Si substrates are studied experimentally in the temperature interval of 30–320 K and at frequencies of 1.0 MHz–40 GHz. The films are grown by laser ablation from a stoichiometric target. For the measurements, planar 0.5-μm-thick gold electrodes (interdigital and straight slot) are photolithography defined on the top surface of NKN films. The slot width between the electrodes is 2.0 or 4.0 μm. At low frequencies(f 1. At microwave frequencies(f>10 GHz), the voltage dependence of the capacitance is given by the NKN film. More than a 13% capacitance change at 40 V dc bias and a Q factor of more than 15 are observed at 40 GHz, which make the structure useful for applications in electrically tunable millimeter-wave devices
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| 3. |
- Abadei, Saeed, 1961, et al.
(författare)
-
Low frequency characterisation of laser ablation deposited thin Na0.5K0.5NbO3 (NKN) films for microwave application
- 2001
-
Ingår i: Integrated Ferroelectrics. - : Informa UK Limited. - 1058-4587 .- 1607-8489. ; 263:1, s. 173-179
-
Tidskriftsartikel (refereegranskat)abstract
- Experimental results on three types of Na0.5K0.5NbO3 (NKN) film capacitor structures are presented. The epitaxial NKN thin films have been deposited on (100) Si (high resistivity), SiO2/Si (low resistivity) and Pt/Si (low resistivity) substrates using laser ablation deposition. Both straight slot and interdigital electrode have been deposited on top of the NKN films. The leakage current and low frequency dielectric properties (I-V, C-V, tanδ-V) of the structures have been measured at 1 MHz as a function of electric field at room temperature. In all three types of capacitor structures the leakage currents in a-b plane are very small, while along c-axis there are extremely large leakage currents. On low resistivity silicon substrates the tunability of the dielectric permittivity is about 12% and loss tangent is low also. On high resistivity (ρ>10 kOhm cm) silicon substrate the tunability at 1 MHz is extremely high, about 10 times, and the losses are also high. On the other hand at microwave frequencies the losses are small (tanδ
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| 4. |
- Abadei, S., et al.
(författare)
-
Microwave properties of tunable capacitors basee on magnetron sputtered ferroelectric Na0.5K0.5NbO3 film on low and high resistivity silicon substrates
- 2001
-
Ingår i: Integrated Ferroelectrics. - : Informa UK Limited. - 1058-4587 .- 1607-8489. ; 39:1-4, s. 359-366
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this work, small signal DC voltage dependent dielectric permittivity, loss tangent, and tuneability of magnetron sputtered epitaxial Na0.5K0.5NO3 films are studied experimentally. (100)-oriented Na0.5K0.5NbO3 films are deposited onto SiO2-buffered CMOS grade low resistivity (p = 10-20 cm) and high resistivity (p = 15-45 kcm) silicon substrates. Planar capacitors with 2 or 4 m gaps between electrodes have been fabricated on top of ferroelectric films. These devices have been characterized in the frequency range 1.0 MHz to 50 GHz at temperatures 30 - 300K. Na0.5K0.5NbO3/SiO2/Si structures on high resistivity silicon substrate exhibit C-V performances typical for Metal-Insulator- Semiconductor (MIS) capacitors. At low frequencies, f 1.0 GHz, the large tuneability and large losses are associated with the MIS structure, while at higher microwave frequencies the tuneability is mainly associated with the ferroelectric, film. At 1.0 MHz and room temperature, the tuneability of Na0.5K0.5NbO3/SiO2/Si structures more than 90%, reducing to 10-15 % at 50 GHz. The losses decrease with increasing the DC bias and frequency. A Q-factor more than 15 at 50 GHz is observed. The dielectric permittivity of the Na0.5K0.5NbO3 film is in the range 50-150 at frequencies 0.045-50 GHz. On low resistivity substrate the performance of Na0.5K0.5NbO3 films is completely screened by the high losses in silicon, and the tuneability is negligible. © 2001 Taylor and Francis.
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| 5. |
- Ahmed, Taimur, 1983, et al.
(författare)
-
Growth temperature dependent dielectric properties of BiFeO3 thin films deposited on silica glass substrates
- 2012
-
Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090. ; 520:13, s. 4470-4474
-
Tidskriftsartikel (refereegranskat)abstract
- We have studied the dependence of dielectric properties on the deposition temperature of BiFeO3 thin films grown by the pulsed laser deposition technique. Thin films have been grown onto amorphous silica glass substrates with pre-patterned Au in-plane capacitor structures. It is shown that on the amorphous glass substrate, BiFeO3 films with a near-bulk permittivity of 26 and coercive field of 80 kV/cm may be grown at a deposition temperature of about 600 degrees C and 1 Pa oxygen pressure. Low permittivity and higher coercive field of the films grown at the temperatures below and above 600 degrees C are associated with an increased amount of secondary phases. It is also shown that the deposition of BiFeO3 at low temperature (i.e. 500 degrees C) and post deposition ex-situ annealing at elevated temperature (700 degrees C) increases the permittivity of a film. The applied bias and time dependence of capacitance of the films deposited at 700 degrees C and ex-situ annealed films are explained by the de-pinning of the ferroelectric domain-walls.
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| 6. |
- Alam Mallick, Shoaib, et al.
(författare)
-
Dielectric properties of Mn doped Bismuth Barium Titanate based ceramic thin films prepared by PLD technique
- 2017
-
Ingår i: Ceramics International. - : Elsevier BV. - 0272-8842. ; 43:12, s. 8778-8783
-
Tidskriftsartikel (refereegranskat)abstract
- In this article, the effect of Mn doping on the permittivity and dielectric loss in 0.67BiFeO(3)-0.33BaTiO(3) (BF-BT) based film bulk acoustic resonator test structures has been investigated. BF-BT thin films were deposited on the fused silica substrates with Pt/TiO2/Ti as bottom electrode. During the study of the BF-BT based parallel-plate structures, it has been revealed that BF-BT is in the ferroelectric state at room temperature. Higher permittivity (epsilon) is observed at a growth temperature of 600 degrees C and lower dielectric loss is achieved at 0.3 wt% Mn doping contents. These results show that the proposed BF-BT based FBAR test structure has a great potential for applications in tunable thin Film Bulk Acoustic Resonator (FBAR) devices. Comparison of the measured and simulation results has been made by utilizing the Mason equivalent circuit.
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| 7. |
- Alleaume, Pierre Franck, et al.
(författare)
-
A highly integrated heterogeneous micro- and mm-wave platform
- 2010
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781424477326 ; , s. 461-464
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A highly integrated platform for micro- and mmwave frequency applications is introduced. The platform utilizes heterogeneous process modules with integrated passive and tunable devices together with silicon and GaAs MMIC technology to achieve outstanding flexibility. The different process modules are accounted for and their feasibility is proven through a number of application demonstrators from 23GHz telecom backhauling and 77GHz automotive radar indicating excellent performance. © 2010 IEEE.
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| 8. |
- Alping, Arne, 1953, et al.
(författare)
-
Micro-electromechanical arrangement
- 2002
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- The present invention refers to a variable capacitor comprising a first conductive layer, a second conductive layer and a semiconductor layer, the first and second layers being arranged to be displaced relative to each other under the influence of an electrostatically generated force. The semiconductor layer constitutes a voltage generator, which when exposed to a radiation produces a voltage for charging the first and second conductive layers and induces the electrostatically generated force
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| 9. |
- ANDERSSON, MICHAEL, 1988, et al.
(författare)
-
Comparison of carrier scattering mechanisms in chemical vapor deposited graphene on fused silica and strontium titanite substrates
- 2014
-
Ingår i: Graphene Week 2014.
-
Konferensbidrag (refereegranskat)abstract
- Graphene is explored for numerous applications for both electronics and photonics. These range from high frequency and low noise field effect transistors to conductive and highly transparent LED electrodes. To exploit the full potential of graphene, the remarkable intrinsic carrier transport properties and tunable, potentially low sheet resistance must be efficiently utilized. However, graphene carrier mobility is currently strongly degraded by extrinsic factors arising mainly from the dielectric environment, i.e. substrate and gate oxide. A proposed route to enhance transport is the use of a high-κ substrate to screen charged impurities at the graphene-substrate interface. In this paper, mobility and carrier concentration in CVD grown graphene films on fused silica (FS, κ=3.9) and strontium titanite (STO, κ=300) substrates are extracted from microwave measurements and compared to Hall data. To model the mobilities scattering by charged impurities (CI), substrate polar phonons (SPP) and resonant centers (RS) are included. Resonant scatterers dominates on strontium titanite and together with charged impurities on fused silica. While resonant scatterers are likely reduced by moving from wet to dry graphene transfer methods, the nominal mobility improvement by screening of charged impurities on high- κ strontium titanite would be masked at room temperature by increased surface phonon scattering.
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| 10. |
- ANDERSSON, MICHAEL, 1988, et al.
(författare)
-
Extraction of carrier transport properties in graphene from microwave measurements
- 2014
-
Ingår i: European Microwave Conference (EuMC), 2014 44th. ; , s. 359 - 362
-
Konferensbidrag (refereegranskat)abstract
- Carrier transport parameters of graphene grown by chemical vapor deposition (CVD) and graphene-metal contacts are extracted from microwave measurements in the frequency range 0.1–20 GHz using Corbino disks. It is shown that the charged impurities are effectively screened by the high permittivity of the SrTiO3 substrate. In the case of fused silica substrate the charged impurities are not completely screened and the mobility is limited either by the charged impurities or/and resonant scatterers depending on their relative concentration.
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| 11. |
- ANDERSSON, MICHAEL, 1988, et al.
(författare)
-
Microwave characterization of Ti/Au-graphene contacts
- 2013
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 103:17, s. 173111-
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we report on a microwave characterization of the interface between Ti/Au contacts and chemical vapor deposition graphene using structures of Corbino geometry, with primary focus on extracting and modeling the capacitance associated with the contact region. It is found that with the current contact resistivity, ρc∼10^−6 Ωcm2, the contact capacitance, on the order Cc∼1 μF/cm2, has a negligible effect on microwave transmission through the contact below ∼100 GHz. Finally, a parallel plate capacitance model for the contact is presented.
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| 12. |
- Aval, Omid, et al.
(författare)
-
Micro-strip circuit for loss reduction
- 2003
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- A printed circuit (1) on a lossy substrate (2) has been provided whereby intermediate structures (11, 12, 17, 18) under the top layer strips (5) have been formed having a width being (d2) smaller than the width (w) of the strip. The intermediate structures (11, 12, 17, 18) are particular well suited for inductors (9) on silicon substrates and result in a considerable increase in the Q-factor of the inductor at microwave frequencies
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| 13. |
- Berg, Håkan, et al.
(författare)
-
High-q tank
- 2001
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- LC tank formed on a lossy substrate material having adjacent strips leading current in opposite directions and being arranged in such a way that substrate currents relating to individual strips (1) induced in the lossy substrate (3) are balancing out one another leading to high Q-values. According to one embodiment of the invention a pair of back to back coupled diodes (18, 19) are arranged between the input terminals of the tank and a pair of DC leads (16, 17) are arranged between the midpoint of the inductor structure and the midpoint between the diodes. The tank according to the invention can be implemented in MMIC devices using standard semiconductor substrates without any special treatment of the substrate being needed
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| 14. |
- Berg, Håkan, et al.
(författare)
-
The effect of longitudinal substrate currents on the losses in silicon substrate coplanar-strip and coplanar waveguides
- 2000
-
Ingår i: International Journal of RF and Microwave Computer-Aided Engineering. - 1096-4290 .- 1099-047X. ; 10:5, s. 284-288
-
Tidskriftsartikel (refereegranskat)abstract
- The strip currents in silicon substrate CPS and CPW induce longitudinal currents in the substrate (along the strips of the lines) causing extra microwave losses. It is shown that these losses may be minimized without introducing extra masks and process steps if the slot widths in the lines are chosen properly
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| 15. |
- Berge, John, 1979, et al.
(författare)
-
Design considerations for tunable bulk acoustic wave resonators based on paraelectric phase BaxSr1-xTiO3 thin films
- 2010
-
Ingår i: 19th International Symposium on the Applications of Ferroelectrics.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Paraelectric phase BaxSr1-xTiO3 (BSTO) is due to the pronounced field induced piezoelectric effect a promising candidate to realize hysteresis-free tunable thin film bulk acoustic wave resonators (TFBARs) at GHz frequencies. Compared to the conventional fixed-frequency TFBAR technology, mainly based on piezoelectric AlN films, the design of tunable BSTO based resonators require additional considerations due to the demanding conditions necessary for the growth of the BSTO active layer (high temperature, O2 ambient). In this work a number of problems and possible solutions are presented for the specific case of solidly mounted resonators based on an acoustic Bragg reflector structure. Simulation results for a proposed tunable resonator based on a BSTO film and a SiO2/HfO2 reflector stack co-optimized for both longitudinal and shear waves are presented and compared to simulations and existing experimental data from other structures.
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| 16. |
- Berge, John, 1979, et al.
(författare)
-
Field and temperature dependent parameters of the dc field induced resonances in BaxSr1-xTiO3-based tunable thin film bulk acoustic resonators
- 2008
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:6, s. 064508-
-
Tidskriftsartikel (refereegranskat)abstract
- Electrically tunable solidly mounted thin film bulk acoustic resonators based on Ba0.25 Sr0.75 Ti O3 and BaTi O3 films are fabricated and measured in wide dc bias voltage and temperature ranges. At room temperature, the tunability of the series and parallel resonances for the Ba0.25 Sr0.75 Ti O3 resonator are 1.7% and 0.3%, respectively, for 15 V bias voltage applied over the 350 nm thick ferroelectric film (43 Vμm). The electromechanical coupling coefficient increases with dc bias up to 3.7% at 15 V. The measured tunability and coupling coefficient are limited partly by the quality of the used films. Potentially, they may be substantially increased for high quality films allowing application of higher dc fields. The resonator quality factor is approximately 100. The measured resonator response is in good agreement with available models based on the electromechanical equations describing the ferroelectric film under applied dc and ac electric fields. Measurements of the resonance frequencies of the Ba0.25 Sr0.75 Ti O3 resonator as a function of temperature in the range 40-520 K reveal a sharp step at 150 K which is related to a structural phase transition of the ferroelectric material. The series resonance frequency is tuned to lower frequencies with increasing dc bias for all temperatures, while the parallel resonance frequency reveals a change in the sign of the tunability at approximately 150 K, from being tuned to lower frequencies at high temperatures to being tuned to higher frequencies at low temperatures. Measurements of BaTi O3 resonators in the temperature range 300-520 K are presented and compared to the Ba0.25 Sr0.75 Ti O3 results. © 2008 American Institute of Physics.
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| 17. |
- Berge, John, 1979, et al.
(författare)
-
The effect of Bragg reflectors on the electromechanical performance of parallel-plate ferroelectric capacitors
- 2010
-
Ingår i: IOP Conference Series: Materials Science and Engineering - Fundamentals and Technology of Multifunctional Oxide Thin Films (Symposium G, EMRS 2009 Spring Meeting) 8–12 June 2009, Strasbourg, France. - 1757-8981. ; 8:1, s. 012011-
-
Konferensbidrag (refereegranskat)abstract
- Parallel-plate capacitors based on ferroelectric thin films are considered as high density capacitors and varactors. Due to the small thickness of the ferroelectric films, typically less than 1.0 mu m, high electric fields are generated even at relatively low voltages inducing piezoelectric effect associated with electrostriction. This induced piezoelectric effect has negative impact on ferroelectric capacitors since it causes extra loss (electroacoustic transformation of microwave energy). In this work the use of Bragg reflectors between the substrate and ferroelectric film is proposed as a possible way of suppression of the enhanced losses associated with the piezoelectric activity of the ferroelectric film.
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| 18. |
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| 19. |
- Berge, John, et al.
(författare)
-
The effect of growth temperature on the nanostructure and dielectric response of BaTiO3 ferroelectric films
- 2007
-
Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090. ; 515:16, s. 6302-6308
-
Tidskriftsartikel (refereegranskat)abstract
- BaTiO3 ferroelectric films were grown on Si/SiO2/Ti/Pt/Au/Pt templates at different temperatures in the range 560-680 degrees C by pulsed laser deposition. Cross section scanning electron microscopy images and atomic force microscopy surface morphology analysis reveal films with columnar structure and in-plane grain size distribution, in the range 10-60 nm, depending on growth temperature. Low-field dielectric measurements were performed as functions of temperature in the range 40-500 K and extemal dc field up to 400 kV/cm. The apparent permittivity of ferroelectric films grown at 680 degrees C shows Curie-Weiss behavior above 400 K with Curie temperature and Curie-Weiss constant 240 K and 1 center dot 10(5) K, respectively. The films grown at lower temperatures reveal a decrease of Curie temperature down to - 80 K, reduced values of apparent permittivity and loss tangent, and broadening of maximum of temperature dependence of apparent permittivity. The film grown at 590 degrees C demonstrates state of the art combination of temperature stability (temperature coefficient of apparent permittivity 300 ppm/K in the range 50350 K), high tunability of apparent permittivity (up to 60% at room temperature), and relatively low loss tangent (less than 0.05 in the frequency range up to 10 GHz). The change in apparent permittivity and its temperature dependence, with variation of growth temperature are analyzed using two different composite models. The first model assumes the film to be a composite with vertical inclusions of low permittivity dielectric material associated with grain boundaries. This model may explain the observed decrease of permittivity with decreasing growth temperature, but not the shift of Curie temperature. The second model assumes a layered type of composite with low permittivity material associated with the film/ electrode interfaces, and allows explanation of the Curie temperature shift. (C) 2006 Elsevier B.V. All rights reserved.
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| 20. |
- Berge, John, et al.
(författare)
-
Tunable bulk acoustic wave resonators based on Ba0.25Sr0.75TiO3 thin films and a HfO2/SiO2 Bragg reflector
- 2011
-
Ingår i: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. - 0885-3010 .- 1525-8955. ; 58:12, s. 2768-2771
-
Tidskriftsartikel (refereegranskat)abstract
- A switchable and tunable bulk acoustic wave resonator based on a paraelectric phase Ba0.25Sr0.75TiO3 thin film and an all-dielectric HfO2/SiO2 Bragg reflector is presented. The achieved tuning range (3.8%) and effective electromechanical coupling coefficient (7.1%) are the highest reported for solidly mounted tunable bulk acoustic wave resonators. The non-conductive Bragg reflector stack provides excellent integration possibilities.
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| 21. |
- Berge, John, et al.
(författare)
-
Tunable Solidly Mounted Thin Film Bulk Acoustic Resonators Based on BaxSr1-xTiO3 Films
- 2007
-
Ingår i: IEEE Microwave and Wireless Components Letters. - 1531-1309 .- 1558-1764. ; 17:9, s. 655-657
-
Tidskriftsartikel (refereegranskat)abstract
- Electrically tunable solidly mounted thin film bulk acoustic resonators based on BaxSr1-xTiO3 films are reported for the first time. The films are acoustically isolated from the silicon substrate by a Bragg reflector stack. Applying DC bias induces piezoelectric effect and an acoustic resonance at approximately 4 GHz. Under 10 V applied DC bias the resonance frequency of the resonators based on Ba0.25Sr0.75TiO3 films is tuned 1.2% to lower frequencies. The Q-factor of these resonators is approximately 120, and the electromechanical coupling coefficient is 0.5%. The resonant frequency of the BaTiO3 based resonators shifts upwards 1.3% under 10 V DC bias, and the -factor is approximately 30, with an electromechanical coupling coefficient of 6.2%.
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| 22. |
- Bergstedt, Leif, et al.
(författare)
-
A detector for detecting electromagnetic radiation
- 2006
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The invention relates to a semiconductor detector for detecting electromagnetic radiation, comprises a semiconductor junction formed by a layer arranged on a substrate. A first and a second electrode are arranged on the layer adjacent to each other and separated by an exposed area of the layer arranged to receive electromagnetic radiation that has an incident angle with respect to the surface of the substrate. Received radiation is transformed to a travelling wave that propagates along the first electrode towards the output end of said first electrode. The detector comprises at least a first tapered structure arranged on the substrate to slow down a signal received from incident radiation at a given cross section of the first electrode, compared to signals received at any preceding cross section of the first electrode, which reduces the phase difference between the received signals so that they sum up substantially in-phase at the output end of said first electrode.
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| 23. |
- Bergstedt, Leif, et al.
(författare)
-
Antenna arrangement
- 2000
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- A single-frequency antenna arrangement includes a ground plane, a dielectric substrate, a first antenna contour located on a first side of the dielectric substrate and a second antenna contour located on second side of the dielectric substrate. The first antenna contour and the second antenna contour have substantially the same dimensions in their longitudinal directions and transverse directions. The first antenna contour and the second antenna contour are galvanically interconnected by at least one connection.
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| 24. |
- Bergstedt, Leif, et al.
(författare)
-
Antenna arrangement and a communication arrangement comprising the same
- 2002
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates an antenna arrangement (23, 330, 430, 530, 630) comprising a fit layer (331, 431, 531, 631) consisting of a dielectric material and a second reflective layer (335, 435, 535, 640, The dielectric material has variable dielectric characteristics. An electromagnetic radiation (50) passing through said first layer (331, 431, 531, 631) and at least partly reflected by said second layer (335, 435, 535, 640) is modulated by varying said variable dielectric characteristics of said first layer.
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| 25. |
- Bergstedt, Leif, et al.
(författare)
-
Arrangement mounted on a printed circuit board and method of producing such an arrangement
- 2004
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- The invention relates to a microwaveguide that is integrated in the dielectric layer of a conductor carrier, e.g. a printed circuit board. The waveguide enables different types of active and/or passive functions intended to influence the signals sent through the waveguide to be integrated at appropriate positions in the waveguide
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| 26. |
- Bergstedt, Leif, et al.
(författare)
-
Arrangement mounted on a printed circuit board and method of producing such an arrangement
- 2002
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The invention relates to a microwaveguide that is integrated in the dielectric layer of a conductor carrier, e.g. a printed circuit board. The waveguide enables different types of active and/or passive functions intended to influence the signals sent through the waveguide to be integrated at appropriate positions in the waveguide
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| 27. |
- Bergstedt, Leif, et al.
(författare)
-
Arrangement relating to conductor carriers and methods for the manufacture of such carriers.
- 2003
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- Method and arrangements for reducing crosstalk between conductors on a conductor carrier, and methods for manufacturing conductor carriers including these arrangements are presented. Crosstalk between the conductors is prevented by providing a dielectric material in the space between each conductor and an earth plane so that the electric field can be tied down within this space and thus prevent leakage of field lines to the co-lateral conductors. The capacitance is increased by an arrangement in the space immediately beneath the conductor so as to reduce the distance between conductors and the earth plane and/or through the medium of a dielectric material that has a higher dielectric index than the dielectric material.
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| 28. |
- Bergstedt, Leif, et al.
(författare)
-
Component for electromagnetic waves and a method for manufacturing the same
- 2007
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates to a method for fabricating a cavity in substrate for a component for electromagnetic waves, the method comprising providing said cavity by removal of material from said substrate by removal of material by immersing the substrate in a liquid bath of a chemical etchant, so that resultant cavity has a top and a bottom side and sidewalls, and said cavity at one of said top and/or bottom sides exhibits an at least a four sided opening having an opening with at least two different adjacent angles. The invention also relates to the component for microwave applications.
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| 29. |
- Bergstedt, Leif, et al.
(författare)
-
Component for electromagnetic waves and a method for manufacturing the same
- 2005
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates to a method for fabricating a cavity in substrate for a component for electromagnetic waves, the method comprising providing said cavity by removal of material from said substrate by removal of material by immersing the substrate in a liquid bath of a chemical etchant, so that resultant cavity has a top and a bottom side and sidewalls, and said cavity at one of said top and/or bottom sides exhibits an at least a four sided opening having an opening with at least two different adjacent angles. The invention also relates to the component for microwave applications.
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| 30. |
- Bergstedt, Leif, et al.
(författare)
-
Microstrip arrangement
- 2001
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- The invention relates to a microstrip arrangement comprising a first and a second microstrip conductor. The two microstrip conductors have essentially the same dimensions in their longitudinal direction and transverse direction, and are galvanically interconnected by means of at least one connection. The two microstrip conductors also extend essentially parallel to one another on either side of a dielectric material. As a result of this design of the microstrip arrangement, the field losses and also other influences caused by the dielectric material will be very considerably reduced, and in practice a resultant microstrip arrangement is obtained, which, with regard to its electrical performance, appears to be suspended in the air. Preferred embodiments comprise a microstrip antenna, a circuit board and a conductor application
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| 31. |
- Buniatian, V., et al.
(författare)
-
Dielectric model of point charge defects in insulating paraelectric perovskites
- 2011
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 110:9
-
Tidskriftsartikel (refereegranskat)abstract
- Some point defects (i.e., oxygen vacancies) create deep trapping levels in the bandgap of the paraelectric phase ferroelectric crystals. Under applied DC field the traps release electrons via the Poole-Frenkel mechanism and become charged. The electric field of a point charge polarizes the crystal locally reducing its permittivity. In this paper a simple theory is proposed for calculating the DC field dependent apparent (measureable) permittivity of a paraelectric crystal with point charge defects. It is shown that the apparent permittivity of a paraelectric crystal may be sufficiently lower as compared with the defectless crystal. This reduction is in addition to the possible reduction of the apparent permittivity associated with the interfacial "dead" layers and strain.
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| 32. |
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| 33. |
- Buniatyan, V. V., et al.
(författare)
-
pH-sensitive properties of barium strontium titanate (BST) thin films prepared by pulsed laser deposition technique
- 2010
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Ingår i: Physica Status Solidi (A) Applications and Materials Science. - : Wiley. - 1862-6319 .- 1862-6300. ; 207:4, s. 824-830
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Tidskriftsartikel (refereegranskat)abstract
- pH sensitive properties of barium strontium titianate (BST) high k thin films as alternative gate material for field-effect capacitive (bio-) chemical sensors based on an electrolyte-insulator semiconductor system have been investigated. The BST films of different composition (Ba0.3Sr0.69TiO3, Ba0.25Sr0.75TiO3 and MG doped Ba0.8Sr0.2Mg0.1Ti0.9O3 were deposited by pulsed laser deposition technique from targets farbicated by self-propagating high-temperatures synthesis. The realised sensors have been electrochemically characterised by means of impedance-spectroscopy, capacitance-voltage and constant-capacitance method. The sensors possess a Nernstian-like pH sensitivity in the concentration range between pH 3 and 11 with a response time of 5-10 s. An equivalent circuit model for the BST-based capacitive field-effect sensor is discussed.(C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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| 34. |
- Carlsson, Erik F., 1968, et al.
(författare)
-
Arrangement and method relating to filtering of signals
- 2000
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- A superconducting notch or band reject filter arrangement includes a superconducting dielectric resonator and a waveguide arrangement including a microstrip line to which the resonator is connected. The resonator is a parallel-plate resonator with a chip of a non-linear dielectric material device on which superconductors are arranged and the waveguide arrangement includes a contact device or a coupling device, the resonator being connected to the contact device of the waveguide arrangement in such a way that electric contact is provided, and the filter arrangement is frequency tuneable. Through the arrangement, the insertion losses are low
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| 35. |
- Carlsson, Erik F., 1968, et al.
(författare)
-
Conformal mapping of the field and charge distributions in multilayered substrate CPWs
- 1999
-
Ingår i: IEEE Transactions on Microwave Theory and Techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 47:8, s. 1544 - 1552
-
Tidskriftsartikel (refereegranskat)abstract
- Conformal mapping (CM) and partial capacitance techniques are used for analytical evaluation of charge/current and electric- and magnetic-field distributions in a multilayered substrate coplanar waveguide (CPW) in the quasi-TEM approximation. The results, compared with finite-element method simulations, show that the magnetic wall assumed at the dielectric-dielectric interfaces in CM is a good approximation for many practical cases. The method is applied to a CPW with a thin ferroelectric film used in tunable microwave devices
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| 36. |
- Carlsson, Erik F., 1968, et al.
(författare)
-
Effect of enhanced current crowding in a CPW with a thin ferroelectric film
- 1997
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 33:2, s. 145-146
-
Tidskriftsartikel (refereegranskat)abstract
- Enhanced current crowding is predicted at the edges of the conducting strips in thin ferroelectric film coplanar waveguides (CPWs). A minimum current crowding depth is expected, which depends on the CPW geometry and dielectric constant of the ferroelectric film. In practical CPW devices the enhanced current crowding can increase the conductor losses by up to four times. The current crowding depth may be smaller than the skin depth or London penetration depth (for high temperature superconducting CPW)
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| 37. |
- Carlsson, Erik F., 1968, et al.
(författare)
-
Effects of package width on K-band high-temperature superconducting filters
- 1995
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Ingår i: Microwave and Optical Technology Letters. - : Wiley. - 1098-2760 .- 0895-2477. ; 10:6, s. 315-317
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of substrate/package width on filter performance is demonstrated and discussed for 18-GHz packaged filters using high-temperature superconducting (HTS), coupled microstrip lines. The filters are made of 0.3-μm YBa2Cu3O7 – ∂8 (YBCO) on MgO substrates with copper ground planes. The HTS filter shows a minimum insertion loss (IL) of 0.9 dB, steep skirts, and very good out-of-band rejection (> 45 dB up to 21 GHz) at 77 K with a bandwidth of 2.8% and a 0.3-dB ripple
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| 38. |
- Carlsson, Erik F., 1968, et al.
(författare)
-
Electric field dependent microwave losses in KTaO3 single crystal with YBa2CU3O7-x electrodes
- 1999
-
Ingår i: Ferroelectrics, Letters Section. - : Informa UK Limited. - 0731-5171 .- 1563-5228. ; 25:5-6, s. 141-152
-
Tidskriftsartikel (refereegranskat)abstract
- We have measured the voltage dependence of the resonant frequency and the microwave losses for parallel-plate resonators based on single crystals KTaO3, with YBa2Cu3O7-x electrodes. The losses increase and the dielectric constant decrease monotonically with applied voltage. Both the dielectric constant and the losses show a hysteretic effect in the voltage dependence. The hysteretic effects may be explained by electric field assisted charge trapping both in the KTaO3, crystal and at the KTaO3/YBa2Cu3O7-x interfaces
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| 39. |
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| 40. |
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| 41. |
- Carlsson, Erik F., 1968, et al.
(författare)
-
Parallel plate microwave devices having tapered current interrupting slots
- 2002
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Patent (övrigt vetenskapligt/konstnärligt)abstract
- A microwave device includes a number of parallel-plate resonators that include at least one dielectric substrate and first and second plates arranged on either side of the substrate. At least one of the plates of each of a number of the parallel-plate resonators includes a current interrupting device such that the current lines of at least one undesired mode are interrupted at their maxima to suppress the undesired mode. There is also described a method of interrupting undesired modes in a microwave device having a number of parallel-plate resonators
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| 42. |
- Chakalov, R, et al.
(författare)
-
Fabrication and investigation of YBa2Cu3O7-delta/Ba0.05Sr0.95TiO3 thin film structures for voltage tunable devices
- 1998
-
Ingår i: Physica C: Superconductivity and its Applications. - 0921-4534. ; 308:3-4, s. 279-288
-
Tidskriftsartikel (refereegranskat)abstract
- High-temperature superconducting/ferroelectric thin film structures were deposited by laser ablation. Three types of voltage tunable devices were fabricated and investigated-trilayer capacitor, planar interdigital capacitor and coplanar waveguide. As ferroelectric the solid solution BaxSr1-xTiO3 was chosen with barium content x = 0.05 because its Curie temperature is close to the liquid nitrogen boiling point (77 K). Temperature and voltage dependences of the Ba0.05Sr0.95TiO3 dielectric constant epsilon(r,BSTO) were studied. High epsilon(r,BSTO) values were determined-up to 3000 at 75 K, 20 GHz and zero de bias. Efficient voltage tunability was demonstrated (up to 40%) at loss level tan delta=0.01-0.1. Compact YBa2Cu3O7-delta/Ba0.05Sr0.95TiO3 coplanar waveguide with as narrow gap as 18 mu m was tested as electrically tunable phase-shifter and field-induced phase shifts of more than 180 degrees were obtained by 35 V de bias at 20 GHz. This improvement was attained by proper choice of the ferroelectric material, accomplished epitaxial growth of the films and decrease of the specific dimensions. (C) 1998 Published by Elsevier Science B.V. All rights reserved.
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| 43. |
- Cho, Coong-Rae, et al.
(författare)
-
Na0.5K0.5NbO3/SiO2/Si Thin Film Varactor
- 2000
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 76, s. 1761-
-
Tidskriftsartikel (refereegranskat)abstract
- Perfectly c-axis oriented micrometer thickNa 0.5 K 0.5 NbO 3 (NKN) films have been prepared on a thermally grown ultrathinSiO 2 template layer onto a Si(001) wafer by the pulsed laser deposition technique. A x-ray diffraction θ–2θ scan reveals multiple-cell structuring of single phase NKN film along the polar axis, while filmsgrown onto amorphous ceramic (Corning) glass show a mixture of slightly c-axis oriented NKN and pyrochlore phases. This implies a small amount ofSiO 2 crystallites distributed in an amorphous matrix inherit Si(001) orientation and promotes highly oriented NKN film growth. NKN filmdielectric permittivityε ′ was found to vary from 114.0 to 107.2 in the frequency range 1 kHz–1 MHz, while the resistivity was on the order of2.6×10 10 Ω cm @ 20 kV/cm. The planar interdigital variable reactance device (varactor) based on theNKN/SiO 2 /Si thin film structure possesses a dissipation factor of 0.8% at 1 MHz and zero bias, electrical tunability of 3.1%, and nA order leakage current at 20 V bias at room temperature.
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| 44. |
- Deleniv, Anatoli, 1969, et al.
(författare)
-
Characterization Accuracy of High-Q Reactors Using Broadband Reflection/Transmission Measurement Techniques
- 2006
-
Ingår i: Proceedings of EUMC 2006, 10-15 Sept. 2006, Manchester, UK. ; , s. 975-979
-
Konferensbidrag (refereegranskat)abstract
- Characterization accuracy of high-Q reactors due to measurement uncertainties is analyzed in this paper. Two broadband techniques based on reflection and transmission type measurements are considered. A differential calculus combined with an equivalent circuit representation of the measurement error are used here to derive simple analytic formulas. It is shown that the accuracy of calibrated VNA is insufficient to obtain accurate loss data. A measurement procedure is proposed that improves the accuracy of loss measurement. A measurement example is given demonstrating the utility of the above approach.
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| 45. |
- Deleniv, Anatoli, 1969, et al.
(författare)
-
Design of the Compact Band-Pass Filter Utilizing Dielectric Loaded
- 2007
-
Ingår i: 37th European Microwave Conference, EUMC; Munich; Germany; 9 October 2007 through 12 October 2007. - 9782874870033 ; 2, s. 886-889
-
Konferensbidrag (refereegranskat)abstract
- A design of a compact Ku-band four pole band-pass filter is reported. The filter is based on twodual-mode dielectric loaded waveguide (WG) resonators providing a significant reduction of the sizesas compared to its single mode counterpart. Each resonator is comprised of a square shaped cut-offwaveguide loaded with a silica glass plate. The filter is realized using a quadruplet cell, which allowstwo symmetric transmission poles to be placed at an arbitrary distance from the pass-band edges. Thisis a welcome feature making this filter useful for both Tx and Rx duplexer channels. A number ofnumerical issues are addressed concerning the modelling using High Frequency Structure Simulator(HFSS). Experimental results are compared with the simulations validating the design approach.
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| 46. |
- Deleniv, Anatoli, 1969, et al.
(författare)
-
Experimental characterization of the 3rd order nonlinearities in thin film parallel-plate ferroelectric varactors
- 2007
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 1424406889 ; 2, s. 683-686
-
Konferensbidrag (refereegranskat)abstract
- The 3rd order nonlinearities in parallel-plate ferroelectric varactors based on thin Ba0.25Sr0.75TiO3 epitaxial films are characterized in wide temperature range. Both, the generated 3rd order harmonic and 3rd order intermodulation products are measured experimentally. The 3rd harmonic IP3 at room temperature is measured to be 35dBm and is favorable as compared to semiconductor competitors. The good agreement between harmonic balance simulation and measured data indicate that the measured low frequency C-V is adequate for accurate design of nonlinear components.
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| 47. |
- Deleniv, Anatoli, 1969, et al.
(författare)
-
Large area photo detector
- 2011
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The invention discloses a photo detector with first and second groups of electrodes. The electrodes of each group are connected to a first common conductor for the group, and are located on a layer of photosensitive material. The electrodes are parallel to and interlaced with each other. The first common conductors are essentially plane, arranged at the same end of their group of electrodes, and arranged as upper and lower conductors parallel to and overlapping each other separated by a dielectric material, and form a signal electrode and a ground plane of a first microstrip line. The first microstrip line acts as a first combiner for currents induced in the electrodes of the two groups and as a matching network for the electrodes and for a load which can be connected to the photo detector
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| 48. |
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| 49. |
- Deleniv, Anatoli, 1969, et al.
(författare)
-
Low loss left-handed media using dielectric ring resonators
- 2008
-
Ingår i: 38th European Microwave Conference, EuMC 2008; Amsterdam; Netherlands; 27 October 2008 through 31 October 2008. - 9782874870064 ; , s. 1418-1420
-
Konferensbidrag (refereegranskat)abstract
- A low loss left handed 1D media using thick film technology is proposed in this work. The design uses a rectangular cut off waveguide periodically loaded by high permittivity dielectric ring resonators. These are considered as a low loss replacement for the split-ring resonators (SRR), responsible for magnetic activity of the media. Simulations are made using eigen-mode solver of HFSS. There the periodic boundary conditions are utilized to emulate the effect of the infinite media. The analysis reveals the propagation of the backward waves below the cut off frequency of the WG indicating left handedness of the propagation media. Another pass-band with the forward wave exists below the cut off of the WG. It is shown that two first pass-bands can be linked so that continuous backward-to-forward transmission is observed.
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| 50. |
- Deleniv, Anatoli, 1969, et al.
(författare)
-
LTCC compatible ferroelectric phase shifters
- 2005
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. ; 1, s. 599-602
-
Tidskriftsartikel (refereegranskat)abstract
- Two phase shifters with novel topologies are presented. The phase shifters are based on LTCC compatible ferroelectric films with er=200, and tand=0.04 at 10 GHz. A Ku-band phase shifter is designed to provide DC bias independent matching in the wide frequency range. It has microstrip design where ferroelectric film is used as a substrate and requires relatively low DC bias voltages. The phase shifter showed -15dB matching in 50% bandwidth and 15deg/dB figure of merit. In X-band phase shifter the ferroelectric film is deposited on the low permittivity substrate. Using such two layered substrate a loaded line phase shifter based on coplanar-plate varactors is realized. The varactors are included in the circuit ground and are connected with the microstrip using vias. This designed allows reduction of overall loss due to more efficient use of ferroelectric. The figure of merit of this phase shifter is 20deg/dB at 10 GHz
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