| 1. |
- Beuerle, Bernhard, 1983-, et al.
(författare)
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Integrated Micromachined Waveguide Absorbers at 220 – 325 GHz
- 2017
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Ingår i: Proceedings of the 47th European Microwave Conference, Nuremberg, October 8-13, 2017. - 9782874870477 ; , s. 695-698
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Konferensbidrag (refereegranskat)abstract
- This paper presents the characterization of integrated micromachined waveguide absorbers in the frequency band of 220 to 325 GHz. Tapered absorber wedges were cut out of four different commercially available semi-rigid absorber ma terials and inserted in a backshorted micromachined waveguide cavity for characterization. The absorption properties of these materials are only specified at 10 GHz, and their absorption behavior above 100 GHz was so far unknown. To study the effect of the geometry of the absorber wedges, the return loss of different absorber lengths and tapering angles was investigated. The results show that longer and sharper sloped wedges from the material specified with the lowest dielectric constant, but not the highest specified absorption, are superior over other geometries and absorber materials. The best results were achieved for 5 mm long absorbers with a tapering angle of 23° in the material RS-4200 from the supplier Resin Systems, having a return loss of better than 13 dB over the whole frequency range of 220 to 325 GHz. These absorber wedges are intended to be used as matched loads in micromachined waveguide circuits. To the best of our knowledge, this is the first publication characterizing such micromachined waveguide absorbers.
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| 2. |
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| 3. |
- Dancila, Dragos, et al.
(författare)
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Micromachined Cavity Resonator Sensors for on Chip Material Characterisation in the 220–330 GHz band
- 2017
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Ingår i: Proceedings of the 47th European Microwave Conference, Nuremberg, October 8-13, 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9782874870477 - 9781538639641 ; , s. 938-941
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Konferensbidrag (refereegranskat)abstract
- A silicon micromachined waveguide on-chip sensor for J-band (220-325 GHz) is presented. The sensor is based on a micromachined cavity resonator provided with an aperture in the top side of a hollow waveguide for sensing purposes. The waveguide is realized by microfabrication in a silicon wafer, goldmetallized and assembled by thermocompression bonding. The sensor is used for measuring the complex relative permittivity of different materials. Preliminary measurements of several dielectric materials are performed, demonstrating the potential of the sensor and methodology.
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| 4. |
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| 5. |
- Krivovitca, Aleksandr, 1991-, et al.
(författare)
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Micromachined Silicon-core Substrate-integrated Waveguides with Coplanar-probe Transitions at 220-330 GHz
- 2018
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Ingår i: Transmission-line structures. - : IEEE. - 9781538650684 - 9781538650677 ; , s. 190-193
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Konferensbidrag (refereegranskat)abstract
- Abstract—In this paper, we present for the first time on, to the best of our knowledge, the first silicon-core micromachined substrate-integrated waveguide (SIW) in the 220-325 GHz frequency range. In contrast to the fabrication methods used for conventional SIW known from substantially lower frequencies, micromachining allows for a full-height waveguide and near-ideal and arbitrarily shaped sidewalls. The silicon dielectric core allows for downscaling the waveguide and components by a factor of 3.4 as compared to an air-filled waveguide. At 330 GHz, the measured waveguide insertion loss is as low as 0.43 dB/mm (0.14 dB/λg, normalized to the guided wavelength). Devices were manufactured using a two-mask micromachining process. Furthermore, a low-loss ultra-wideband coplanar-waveguide (CPW) transition was successfully implemented, which comprises the very first CPW-to-SIW transitions in this frequency range. The measured transition performance is better than 0.5 dB insertion loss (average of 0.43 dB in the band above 15% above the waveguide-cutoff frequency), which is lower than previously reported CPW-to-SIW transitions even at 3 times lower frequencies, and the return loss is better than 14 dB for 75% of the waveguide band.
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| 6. |
- Malmqvist, Robert, et al.
(författare)
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A 220-325 GHz Low-Loss Micromachined Waveguide Power Divider
- 2017
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Ingår i: Proceedings of the 2017 Asia-Pacific Microwave Conference (APMC). - : IEEE. ; , s. 291-294
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Konferensbidrag (refereegranskat)abstract
- A J-band (220-325 GHz) silicon micromachined waveguide power divider based on a tee-shape topology is presented. To characterise the power divider a test circuit was designed with one output path connected using a low return loss 90° multi-stepped bend while the other output path uses an onchip matched waveguide load filled with an absorbing material. The power divider is fabricated using a micromachined waveguide technology employing a double H-plane split which results in low losses. Measured transmission and reflection coefficients are equal to -3.5 dB ± 0.4 dB at 231-330 GHz and between -10 dB and -20 dB at 220-320 GHz, respectively. A good agreement between the simulated and measured data was obtained by taking the microfabrication sidewall profile (undercut) into account in the simulations. To the best of our knowledge, this is the first time a low-loss micromachined power divider of this type is characterised within this frequency range.
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| 7. |
- Oberhammer, Joachim, 1976-
(författare)
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Novel RF MEMS Switch and Packaging Concepts
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Radio-frequency microelectromechanical systems (RF~MEMS) are highly miniaturized devices intended to switch, modulate, filter or tune electrical signals from DC to microwave frequencies. The micromachining techniques used to fabricate these components are based on the standard clean-room manufacturing processes for high-volume integrated semiconductor circuits. RF~MEMS switches are characterized by their high isolation, low insertion loss, large bandwidth and by their unparalleled signal linearity. They are relatively simple to control, are very small and have almost zero power consumption. Despite these benefits, RF~MEMS switches are not yet seen in commercial products because of reliability issues, limits in signal power handling and questions in packaging and integration. Also, the actuation voltages are typically too high for electronics applications and require additional drive circuitry. This thesis presents a novel MEMS switch concept based on an S-shaped film actuator, which consists of a thin and flexible membrane rolling between a top and a bottom electrode. The special design makes it possible to have high RF isolation due to the large contact distance in the off-state, while maintaining low operation voltages due to the zipper-like movement of the electrostatic dual-actuator. The switch comprises two separately fabricated parts which allows simple integration even with RF circuits incompatible with certain MEMS fabrication processes. The two parts are assembled by chip or wafer bonding which results in an encapsulated, ready-to-dice package. The thesis discusses the concept of the switch and reports on the successful fabrication and evaluation of prototype devices. Furthermore, this thesis presents research results in wafer-level packaging of (RF) MEMS devices by full-wafer bonding with an adhesive intermediate layer, which is structured before bonding to create defined cavities for housing MEMS devices. This technique has the advantage of simple, robust and low temperature fabrication, and is highly tolerant to surface non-uniformities and particles in the bonding interface. It allows cavities with a height of up to many tens of micrometers to be created directly in the bonding interface. In contrast to conventional wafer-level packaging methods with individual chip-capping, the encapsulation is done using a single wafer-bonding step. The thesis investigates the process parameters for patterned adhesive wafer bonding with benzocyclobutene, describes the fabrication of glass lid packages based on this technique, and introduces a method to create through-wafer electrical interconnections in glass substrates by a two-step etch technique, involving powder-blasting and chemical etching. Also, it discusses a technique of improving the hermetic properties of adhesive bonded structures by additional passivation layers. Finally, it presents a method to substantially improve the bond strength of patterned adhesive bonding by using the solid/liquid phase combination of a patterned polymer layer with a contact-printed thin adhesive film.
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| 8. |
- Svedin, Jan, et al.
(författare)
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A 230-300 GHz Low-Loss Micromachined Waveguide Hybrid Coupler
- 2017
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Ingår i: Proceedings of the 47th European Microwave Conference. ; , s. 616-619
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Konferensbidrag (refereegranskat)abstract
- A silicon micromachined waveguide hybrid coupler for J-band (220-325 GHz) applications is presented. The coupling and phase shifting functions are realised using a 90° ridged waveguide phase shifter, a joint waveguide section and a port extension. The hybrid coupler is fabricated using a micromachined waveguide technology employing a double H-plane split that results in low losses. For the design band 230–300 GHz, initial VNA measurements indicate coupling coefficients of -3.2±0.4 dB, amplitude imbalance better than -0.5/+0.3 dB, phase imbalance better than -14°/+11° and an input reflection coefficient below -14 dB. To the best of our knowledge, this is the first time a low-loss micromachined hybrid coupler of this type is characterised within this frequency range.
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