| 1. |
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| 2. |
- Baghchehsaraei, Zargham, et al.
(author)
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MEMS 30μm-thick W-band waveguide switch
- 2012
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In: European Microwave Week 2012. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1055-1058, s. 675-678, s. 1055-1058
-
Conference paper (peer-reviewed)abstract
- This paper presents for the first time a novel concept of a MEMS waveguide switch based on a reconfigurable surface, whose working principle is to short-circuit or to allow for free propagation of the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. This transmissive surface is only 30μm thick and consists of up to 1260 reconfiguring cantilevers in the waveguide cross-section, which are moved simultaneously by integrated MEMS comb-drive actuators. For the first fabrication run, the yield of these reconfigurable elements on the chips was 80-86%, which still was good enough for resulting in a measured insertion loss in the open state of better than 1dB and an isolation of better than 20dB for the best designs, very wideband from 62 to 75GHz. For 100% fabrication yield, HFSS simulations predict that an insertion loss in the open state of better than 0.1dB and an isolation of better than 30dB in the closed state are possible for designs with 800 and more contact points for this novel waveguide switch concept.
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| 3. |
- Beuerle, Bernhard, 1983-, et al.
(author)
-
A CPW Probe to Rectangular Waveguide Transition for On-wafer Micromachined Waveguide Characterization
-
Other publication (other academic/artistic)abstract
- A new transition from coplanar waveguide probe to micromachined rectangular waveguide for on-wafer device characterization is presented in this article. The transition is fabricated in the same double H-plane split silicon micromachined waveguide technology as the devices under test, requiring no additional post-processing or assembly steps. We outline the design and fabrication process of the transition for the frequency band of 220 – 330 GHz. A coplanar waveguide structure acts as the probing interface, with an E-field probe protruding in the waveguide cavity exciting the fundamental waveguide mode. Guard structures around the E-field probe increase the aspect ratio during deep reactive ion etching and secure its geometry. A full equivalent circuit model is provided by analyzing its working principle. RF characterization of fabricated devices is performed for both single-ended and back-to-back configurations. Measured S-parameters of the single-ended transition are obtained by applying a two-tiered calibration and are analyzed using the equivalent circuit model. The insertion loss of the single-ended transition lies between 0.3 dB and 1.5 dB over the whole band, with the return loss in excess of 8 dB. In addition to previously reported characterization of a range of devices under test the viability of the transition for on-wafer device calibration is demonstrated by characterizing a straight waveguide line, achieving an insertion loss per unit length of 0.02 – 0.08 dB/mm in the frequency band of 220 – 330 GHz.
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| 4. |
- Beuerle, Bernhard, 1983-, et al.
(author)
-
A CPW Probe to Rectangular Waveguide Transition for On-Wafer Micromachined Waveguide Characterization
- 2024
-
In: IEEE Transactions on Terahertz Science and Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 2156-342X .- 2156-3446. ; 14:1, s. 98-108
-
Journal article (peer-reviewed)abstract
- A new transition from coplanar waveguide probe to micromachined rectangular waveguide for on-wafer device characterization is presented in this article. The transition is fabricated in the same double H-plane split silicon micromachined waveguide technology as the devices under test, requiring no additional post-processing or assembly steps. We outline the design and fabrication process of the transition for the frequency band of 220–330 GHz. A coplanar waveguide structure acts as the probing interface, with an E-field probe protruding in the waveguide cavity exciting the fundamental waveguide mode. Guard structures around the E-field probe increase the aspect ratio during deep reactive ion etching and secure its geometry. A full equivalent circuit model is provided by analyzing its working principle. RF characterization of fabricated devices is performed for both single-ended and back-to-back configurations. Measured S-parameters of the single-ended transition are obtained by applying a two-tiered calibration and are analyzed using the equivalent circuit model. The insertion loss of the single-ended transition lies between 0.3 dB and 1.5 dB over the whole band, with the return loss in excess of 8 dB. In addition to previously reported characterization of a range of devices under test the viability of the transition for on-wafer device calibration is demonstrated by characterizing a straight waveguide line, achieving an insertion loss per unit length of 0.02–0.08 dB/mm in the frequency band of 220–330 GHz.
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| 5. |
- Beuerle, Bernhard, 1983-, et al.
(author)
-
A Very Low Loss 220–325 GHz Silicon Micromachined Waveguide Technology
- 2018
-
In: IEEE Transactions on Terahertz Science and Technology. - : IEEE. - 2156-342X .- 2156-3446. ; 8:2, s. 248-250
-
Journal article (peer-reviewed)abstract
- This letter reports for the first time on a very low loss silicon micromachined waveguide technology, implemented for the frequency band of 220–325 GHz. The waveguide is realized by utilizing a double H-plane split in a three-wafer stack. This ensures very low surface roughness, in particular on the top and bottom surfaces of the waveguide, without the use of any surface roughness reduction processing steps. This is superior to previous micromachined waveguide concepts, including E-plane and single H-plane split waveguides. The measured average surface roughness is 2.14 nm for the top/bottom of the waveguide, and 163.13 nm for the waveguide sidewalls. The measured insertion loss per unit length is 0.02–0.07 dB/mm for 220–325 GHz, with a gold layer thickness of 1 μm on the top/bottom and 0.3 μm on the sidewalls. This represents, in this frequency band, the lowest loss for any silicon micromachined waveguide published to date and is of the same order as the best metal waveguides.
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| 6. |
- Beuerle, Bernhard, 1983-, et al.
(author)
-
Integrated Micromachined Waveguide Absorbers at 220 – 325 GHz
- 2017
-
In: Proceedings of the 47th European Microwave Conference, Nuremberg, October 8-13, 2017. - 9782874870477 ; , s. 695-698
-
Conference paper (peer-reviewed)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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| 7. |
- Beuerle, Bernhard, 1983-, et al.
(author)
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Integrating InP MMICs and Silicon Micromachined Waveguides for sub-THz Systems
-
Other publication (other academic/artistic)abstract
- A novel co-designed transition from InP monolithic microwave integrated circuits to silicon micromachined waveguides is presented. The transition couples a microstrip line to a substrate waveguide sitting on top of a vertical waveguide. The silicon part of the transition consists of a top and a bottom chip, fabricated in a very low-loss silicon micromachined waveguide technology using silicon on insulator wafers. The transition has been designed, fabricated and characterized for 220–330 GHz in a back-to-back configuration. Measured insertion loss is 3–6 dB at 250–300 GHz, and return loss is in excess of 5 dB.
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| 8. |
- Beuerle, Bernhard, et al.
(author)
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Integrating InP MMICs and Silicon Micromachined Waveguides for Sub-THz Systems
- 2023
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In: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 44:10, s. 1800-1803
-
Journal article (peer-reviewed)abstract
- A novel co-designed transition from InP monolithic microwave integrated circuits to silicon micromachined waveguides is presented. The transition couples a microstrip line to a substrate waveguide sitting on top of a vertical waveguide. The silicon part of the transition consists of a top and a bottom chip, fabricated in a very low-loss silicon micromachined waveguide technology using silicon on insulator wafers. The transition has been designed, fabricated and characterized for 220 GHz to 330 GHz in a back-to-back configuration. Measured insertion loss is 3 dB to 6 dB at 250 GHz to 300 GHz , and return loss is in excess of 5 dB.
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| 9. |
- Beuerle, Bernhard, 1983-, et al.
(author)
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Low-Loss Silicon Micromachined Waveguides Above 100 GHz Utilising Multiple H-plane Splits
- 2018
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In: Proceedings of the 48th European Microwave Conference, Madrid, October 1-3, 2018. - : Institute of Electrical and Electronics Engineers (IEEE). - 9782874870514 ; , s. 1041-1044
-
Conference paper (peer-reviewed)abstract
- For sub-millimeter and millimeter wave applications rectangular waveguides are an ideal transmission medium. Compared to conventional, metal-milled rectangular waveguides, silicon micromachined waveguides offer a number of advantages. In this paper we present a low-loss silicon micromachined waveguide technology based on a double H-plane split for the frequency bands of 110 – 170 GHz and 220 – 330 GHz. For the upper band a reduced height waveguide is presented, which achieves a loss per unit length of 0.02 – 0.10 dB/mm. This technology has been further adapted to implement a full height waveguide for the lower frequency band of 110 – 170 GHz. The full height waveguide takes advantage of the benefits of the double H-plane split technique to overcome the challenges of fabricating micromachined waveguides at lower frequencies. With measured insertion loss of 0.007 – 0.013 dB/mm, averaging 0.009 dB/mm over the whole band, this technology offers the lowest insertion loss of any D-band waveguide to date. The unloaded Q factor of the D-band waveguide technology is estimated to be in excess of 1600, while a value of 750 has been measured for the reduced height upper band waveguide.
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| 10. |
- Beuerle, Bernhard, 1983-, et al.
(author)
-
Micromachined Waveguides with Integrated Silicon Absorbers and Attenuators at 220–325 GHz
- 2018
-
In: IEEE MTT-S International Microwave Symposium, IEEE conference proceedings, 2018. - : IEEE.
-
Conference paper (peer-reviewed)abstract
- This paper reports for the first time on micromachined waveguides with integrated micromachined silicon absorbers. In contrast to epoxy-based microwave absorbers, micromachined lossy silicon absorbers are fully compatible with high temperature fabrication and assembly processes for micromachined waveguides. Furthermore, micromachining enables the fabrication of exact, near ideal taper tips for the silicon absorbers, whereas the tip of epoxy-based absorbers cannot be shaped accurately and reproducibly for small waveguides. Silicon of different conductivity is a very well understood and characterized dielectric material, in contrast to conventional absorber materials which are not specified above 60 GHz. Micromachined silicon waveguides with integrated absorbers and attenuators were designed, fabricated and characterized in the frequency band of 220 – 325 GHz. The return and insertion loss for various taper-geometry variations of double-tip tapered absorbers and attenuators was studied. The average return loss for the best investigated device is 19 dB over the whole band. The insertion loss of the two-port attenuators is 16 – 33 dB for different designs and shows an excellent agreement to the simulated results. The best measured devices of the one-port absorbers exhibit an average and worst-case return loss of 22 dB and 14 dB, respectively, over the whole band. The return loss is not characterized by a good simulation-measurement match, which is most likely attributed to placement tolerances of the absorbers in the waveguide cavities affecting the return but not the insertion loss.
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| 11. |
- Beuerle, Bernhard, 1983-, et al.
(author)
-
On-wafer Micromachined Waveguide Characterization with CPW Probe to Rectangular Waveguide Transition up to 500 GHz
-
Other publication (other academic/artistic)abstract
- We report on coplanar waveguide to micromachined waveguide transitions for on-wafer device characterization. The transitions are designed in a silicon micromachined waveguide technology using silicon on insulator wafers together with the devices under test. A previous design at 220–330 GHz with in-band radiation characteristic is modified to eliminate the radiation and allow it to be scaled to higher frequencies. Simulation results for 220–330 GHz and 330–500 GHz are obtained, and the transition has an insertion loss of better than 0.5 and 1.2 dB, respectively. The transition is fabricated and characterized at 220–330 GHz, with an insertion loss of better than 0.7 dB and a return loss in excess of 10 dB over the whole band.
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| 12. |
- Beuerle, Bernhard, 1983-
(author)
-
Silicon micromachined waveguide components for terahertz systems
- 2020
-
Doctoral thesis (other academic/artistic)abstract
- This thesis presents silicon micromachined waveguide components for sub-terahertz and terahertz (THz) systems fabricated by deep reactive ion etching (DRIE). Historically the main driving force for the development of THz systems has been space-based scientific instruments for astrophysics, planetary and Earth science missions. Recent advances in active and passive components for the THz frequency range increased its usage in areas such as imaging, security, communications and biological instrumentation. Traditionally the primary technology for components and interconnections approaching THz frequencies has been hollow metal waveguides fabricated by computer numerical controlled (CNC) milling. Systems using this technology are bulky and hand-assembled, getting more expensive and complicated with an increasing complexity of the system. In recent years silicon micromachining has emerged as a viable alternative for THz components and integrated systems promising more compact integrated systems.The thesis reports on a new low-loss silicon micromachined waveguide technology using silion-on-insulator (SOI) wafers. Several low-loss waveguide components in the frequency range of 220–330 GHz have been fabricated and characterized, such as hybrid couplers, splitters and matched loads. Furthermore, an investigation of fabrication accuracy and repeatability for high-Q filters in the sub-THz frequency range using the same waveguide technology is presented.For on-wafer waveguide characterization a novel CPW probe to micromachined waveguide transition concept is introduced. The transition is co-fabricated together with the devices under test in the same waveguide technology using SOI technology. It consists of a CPW probing interface and a pin protruding into the waveguide cavity acting as an E-field probe to excite the dominant mode of the rectangular waveguide. Designed and characterized for the frequency range of 220–330 GHz, the transition was successfully used for on-wafer characterization of the waveguide components previously presented. The scalability of the concept to higher frequencies is shown by presenting a modified transition capable of device characterization up to 500 GHz.The integration of monolithic micromachined integrated circuits (MMICs) with silicon micromachined waveguides is investigated, with a focus on scalability to higher frequencies and their compatibility with industrial assembly tools. A new integration concept for THz systems is presented and a back-to-back transition structure for the integration of SiGe MMICs with silicon micromachined waveguides at D-band frequencies (110–170 GHz) has been characterized. Furthermore, a co-designed transition from InP MMIC to silicon micromachined rectangular waveguide is presented, consisting of a compact microstrip to waveguide transition and a vertical waveguide to in-plane waveguide bend in the silicon micromachined waveguide technology. The concept has been fabricated and characterized in a back-to-back configuration for the frequency range of 220–330 GHz.
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| 13. |
- Campion, James, 1989-, et al.
(author)
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An Ultra Low-Loss Silicon-Micromachined Waveguide Filter for D-Band Telecommunication Applications
- 2018
-
In: 2018 IEEE/MTT-S International Microwave Symposium. - : IEEE. - 9781538650677 ; , s. 583-586
-
Conference paper (peer-reviewed)abstract
- A very low-loss micromachined waveguide bandpassfilter for use in D-band (110–170GHz) telecommunication applicationsis presented. The 134–146GHz filter is implemented in a silicon micromachined technology which utilises a double H-plane split, resulting in significantly lower insertion loss than conventional micromachined waveguide devices. Custom split-blocks are designed and implemented to interface with the micromachined component. Compact micromachined E-plane bends connect the split-blocks and DUT. The measured insertion loss per unit length of the waveguide technology (0.008–0.016 dB/mm) is the lowest reported to date for any micromachined waveguide at D-band. The fabricated 6-pole filter, with a bandwidth of 11.8 GHz (8.4%), has a minimum insertion loss of 0.41 dB, averaging 0.5 dB across its 1 dB bandwidth, making it the lowest-loss D-band filter reported to date in any technology. Its return loss is better than 20 dB across 85% of the same bandwidth. The unloaded quality factor of a single cavity resonator implemented in this technology is estimated to be 1600.
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| 14. |
- Campion, James, 1989-
(author)
-
Exploiting the Terahertz Spectrum with Silicon Micromachining : Waveguide Components, Systems and Metrology
- 2021
-
Doctoral thesis (other academic/artistic)abstract
- The terahertz spectrum (300 GHz - 3 THz) represents the final frontier for modern electronic and optical systems, wherein few low-cost, volume-manufacturable solutions exist. THz frequencies are of great scientific and commercial interest, with applications as diverse as radio astronomy, sensing and imaging and wireless communications. Current THz technology is restricted by its expense, form-factor and performance limitations. Future exploitation of this spectrum requires the development of new technologies which support its use in high-volume applications. Any such technology must offer excellent mechanical and electrical performance and be compatible with industrial grade tools and processes. In response to this, this thesis presents the development of silicon micromachined waveguide components and systems for THz and sub-THz frequencies. Silicon micromachining offers a unique combination of small feature sizes and low surface roughness and manufacturing tolerances in a scalable process.At the core of this work lies a new silicon-on-insulator (SOI) waveguide technology which minimises surface roughness to provide low insertion loss. Waveguide filters and diplexers between 100–500 GHz are implemented using this technology, each with state-of-the-art performance. A new platform for waveguide systems is developed to enable fully micromachined systems to be realised. In contrast to previous solutions, this platform integrates of all DC, intermediate and radio frequency signals in a single medium. Two unique non-galvanic transitions provide interfaces to active components and metallic waveguides. Semi-automated industrial tools perform system assembly with high accuracy and are used to implement complete transceivers for wireless communication at 110–170 GHz. Commercial-grade silicon germanium integrated circuits are used for all active components. This represents the first step in the adoption of this new technology in an industrial scenario.Large-scale use of the THz spectrum necessitates a shift from discrete components to complete integrated systems, in a similar matter to that seen in digital electronics and will require accurate, high-throughput characterisation and verification infrastructures. To support this, two transitions from co-planar waveguide probes to rectangular waveguide are proposed to allow for device characterisation in an on-wafer environment from 220–500 GHz. The accuracy and precision of the SOI micromachining process, coupled with the mechanical properties of silicon, make it highly suited to the creation of precision metrology standards. By harnessing these properties, a new class of micromachined waveguide calibration standards is developed, the peformance of which exceeds current solutions. Traceability of the standards is documented through detailed mechanical, electrical and statistcal analysis of fabricated samples.This work presented in thesis enables the development of THz components and systems, and methods to test them, in an established, high-volume technology, enabling their use in a wide range of applications.
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| 15. |
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| 16. |
- Campion, James, 1989-, et al.
(author)
-
Repeatability of Silicon Micromachined Waveguide Components Connected to Metallic Waveguide Flanges at 220 - 330 GHz
-
Other publication (other academic/artistic)abstract
- This paper investigates the repeatability of silicon micromachined waveguide components which are connected to metallic waveguide flanges and the impact of misalignment on it. Quantifying the repeatability of such components is essential to enable their use in high-volume applications, where randomd evice performance variations must be avoided. Misalignment is a significant contributor to experimental uncertainty andlimits the achievable return loss between a pair of waveguides. Misalignment is not the only factor which affects repeatability - variations in clamping pressure and mechanical wear to the various components also have an influence. These effects are not well understood as they are difficult to quantify, model or simulate. Here, we apply the elliptical alignment holes concept to greatly reduced the potential misalignment between siliconmicromachined chips and metallic flanges without the need to oversize the chip’s alignment holes. We design and fabricaten umerous samples which allow varying levels of misalignment and characterise them in a 2-port measurement setup from 220 –330 GHz. Mechanical wear of the micromachined components is examined and compared to the experimental results. The elliptical alignment hole concept is found to reduce experimentaluncertainty in |S11 | and |S21 | by up to a factor of 1.7 and 1.25, respectively, without reducing the probability of the chip fitting on the metallic flange.
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| 17. |
- Campion, James, 1989-, et al.
(author)
-
Silicon-Micromachined Waveguide Calibration Shims for Terahertz Frequencies
- 2019
-
In: Proceedings 2019 IEEE MTT-S International Microwave Symposium (IMS). - : IEEE.
-
Conference paper (peer-reviewed)abstract
- A new method of realising precision waveguide shims for use in THz Through-Reflect-Line (TRL) calibrations, based on silicon-micromachining, is introduced. The proposed calibration shims combine a thin λ/4 silicon layer, co-fabricated with a thicker layer which provides mechanical support. This design overcomes the limitations of CNC milling for the creation of calibration shims, facilitating use of standard TRL calibration at currently challenging frequencies. The novel shim fits inside the inner recess of a standard waveguide flange and is compatible with conventional flange alignment pins. Five micromachined shims were fabricated in a silicon-on-insulator process for operation in the WM-570 waveguide band (325–500GHz). The fabricated shims show excellent performance across the entire band, with return loss in excess of 25dB, insertion loss below 0.2 dB and high uniformity between samples. Verification reveals that the micromachined shims have an electrical length within 2% of the expected value. Comparative measurements of a DUT calibrated with the proposed shim and a previously un-used conventional metallic shim show that the novel concept offers equivalent, if not better, performance. The mechanical design of the micromachined shim and the rigid nature of silicon ensure that it will not suffer from performance degradation with repeated use, as is problematic with thin metallic shims. This work enables the creation of low-cost, highly-repeatable, traceable calibration shims with micrometer feature-sizes and high product uniformity, surpassing the limits of current techniques.
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| 18. |
- Campion, James, 1989-, et al.
(author)
-
Toward Industrial Exploitation of THz Frequencies : Integration of SiGe MMICs in Silicon-Micromachined Waveguide Systems
- 2019
-
In: IEEE Transactions on Terahertz Science and Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 2156-342X .- 2156-3446. ; 9:6, s. 624-636
-
Journal article (peer-reviewed)abstract
- A new integration concept for terahertz (THz) systems is presented in this article, wherein patterned silicon-on-insulator wafers form all DC, IF, and RF networks in a homogeneous medium, in contrast to existing solutions. Using this concept, silicon-micromachined waveguides are combined with silicon germanium (SiGe) monolithic microwave integrated circuits (MMICs) for the first time. All features of the integration platform lie in the waveguide’s H-plane. Heterogeneous integration of SiGe chips is achieved using a novel in-line H-plane transition. As an initial step toward complete systems, we outline the design, fabrication, and assembly of back-to-back transition structures, for use at D-band frequencies (110ï¿œ170 GHz). Special focus is given to the industrial compatibility of all components, fabrication, and assembly processes, with an eye on the future commercialization of THz systems. Prototype devices are assembled via two distinct processes, one of which utilizes semiautomated die-bonding tools. Positional and orientation tolerances for each process are quantified. An accuracy of $\pm \text3.5\; μ \textm$, $\pm \text1.5 °$ is achieved. Measured $S$-parameters for each device are presented. The insertion loss of a single-ended transition, largely due to MMIC substrate losses, is 4.2ï¿œ5.5 dB, with a bandwidth of 25 GHz (135ï¿œ160 GHz). Return loss is in excess of 5 dB. Measurements confirm the excellent repeatability of the fabrication and assembly processes and, thus, their suitability for use in high-volume applications. The proposed integration concept is highly scalable, permitting its usage far into the THz frequency spectrum. This article represents the first stage in the shift to highly compact, low-cost, volume-manufacturable THz waveguide systems.
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| 19. |
- Dancila, Dragos, et al.
(author)
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Micromachined Cavity Resonator Sensors for on Chip Material Characterisation in the 220–330 GHz band
- 2017
-
In: Proceedings of the 47th European Microwave Conference, Nuremberg, October 8-13, 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9782874870477 - 9781538639641 ; , s. 938-941
-
Conference paper (peer-reviewed)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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| 20. |
- Glubokov, Oleksandr, et al.
(author)
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Investigation of Fabrication Accuracy and Repeatability of High-Q Silicon-Micromachined Narrowband Sub-THz Waveguide Filters
- 2019
-
In: IEEE transactions on microwave theory and techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 67:9, s. 3696-3706
-
Journal article (peer-reviewed)abstract
- This paper investigates the fabrication accuracy and repeatability of micromachined quadruplet filters designed at a center frequency of 270 GHz with a 5-GHz bandwidth using a versatile multilayer chip platform which allows for axially arranged waveguide ports. A large number of narrowband silicon-micromachined filters arranged on multiple chips are investigated for fabrication imperfections, assembly misalignment, and fabrication yield, employing fabrication-prediction and different chip-to-chip self-alignment feature strategies. A numerical technique for characterization of the entire fabrication process of the filters through extracting the error statistics for coupling coefficients of a large number of different samples from separately assembled chips is proposed. A total of 47 test filters in effectively 15 different design variants have been fabricated in two fabrication runs, evaluated, and analyzed. The most critical sources of errors are determined. The expected accuracy of the entire filters fabrication process is demonstrated through the yield analysis based on the collected error statistics.
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| 21. |
- Glubokov, Oleksandr, et al.
(author)
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Micromachined Bandpass Filters with Enhanced Stopband Performance and Q-factor of 950 at 700 GHz
- 2021
-
In: Proceedings IEEE MTT-S International Microwave Symposium Digest. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 204-206
-
Conference paper (peer-reviewed)abstract
- In this paper, we present two bandpass filters at 687.5 and 700 GHz with fractional bandwidths (FBW) of 3.64% and 1% respectively. Both 4th-order all-pole filters utilize a pair of dual-mode cavities: the first filter uses elliptic cavities with quasi-TMno degenerate modes, while the second one uses rectangular cavities with TM410-TM140 modes. In the latter, the coupling slots between the cavities are arranged to enhance the stopband performance by suppressing spurious resonances in the stopband. The filters are fabricated using silicon micromachining with gold metallization. The measured average insertion loss in the passband of the 3.64% FBW filter is 1.45 dB, and 2.5 dB for the 1% FBW filter. The experimentally extracted unloaded quality-factors are 450 for the elliptic cavities and 950 for the rectangular cavities. The measured filter performance of the first prototypes agrees very well with the simulation results, exhibiting a frequency shift of less than 0.7%. These are the best insertion loss and quality factors ever published in this frequency range for narrow-band filters, and the first time that a 1%-FBW microwave filter is demonstrated above 500 GHz.
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| 22. |
- Glubokov, Oleksandr, et al.
(author)
-
Micromachined Filters at 450 GHz With 1% Fractional Bandwidth and Unloaded Q Beyond 700
- 2019
-
In: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 9:1
-
Journal article (peer-reviewed)abstract
- This letter presents two silicon-micromachined narrowband fourth-order waveguide filter concepts with center frequency of 450 GHz, which are the first narrowband submillimeter-wave filters implemented in any technology with a fractional bandwidth as low as 1%. Both filters designs are highly compact and have axial port arrangements, so that they can be mounted directly between two standard waveguide flanges without needing any split-block interposers. The first filter concept contains two TM 110 dual-mode cavities of circular shape with coupling slots and perturbations arranged in two vertically stacked layers, while the second filter concept is composed of four TE 101 series resonators arranged in a folded, two-level topology without crosscouplings. Prototype devices are fabricated in a multilayer chip platform by high-precision, low-surface roughness deep-silicon etching on silicon-on-insulator wafers. The measured passband insertion loss of two prototype devices of the dual-mode circular-cavity filters is 2.3 dB, and 2.6 dB for three prototypes of the folded filter design. The corresponding extracted unloaded quality factors of the resonators are 786 ± 7 and 703 ± 13, respectively, which are the best so far reported for submillimeter-wave filters in any technology. The presented filters are extremely compact in terms of size; their footprints have areas of only 0.53 and 0.55 mm 2 , respectively, and the thickness between the waveguide flanges is 0.9 mm.
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| 23. |
- Glubokov, Oleksandr, et al.
(author)
-
Multilayer Micromachined Dual-Mode Elliptic Cavities Filter With Axial Feeding at 270 GHz
- 2018
-
Conference paper (peer-reviewed)abstract
- A silicon micromachined multilayer bandpass filters using dual-mode elliptic cavities at 270 GHz is shown.The cross-coupled filter has been designed taking into accountthe side-walls non-verticality. Good agreement with simulations has been obtained for the filter. Excellent performancein terms of losses has been demonstrated.
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| 24. |
- Gomez-Torrent, Adrian, et al.
(author)
-
A Silicon Micromachined 220-330 GHz Turnstile Orthomode Transducer (OMT) in a Low-Loss Micromachining Fabrication Platform
- 2018
-
Conference paper (peer-reviewed)abstract
- The work presented in this paper reports on the first wideband OMT in any frequency band implemented by micromachining. This turnstile-junction design provides full waveguide-band operation (220-330 GHz) and is the first implementation of a turnstile-OMT above 110 GHz, since very accurate fabrication is required for this topology. The measured insertion loss is below 0.5 dB and below 0.6 dB for the two polarizations, respectively, with an average measured return loss of 22 dB. Except for some spikes which still are below 30 dB, the cross-polarization is between 50 and 60 dB.
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| 25. |
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