| 1. |
- Baghchehsaraei, Zargham, 1982-, et al.
(författare)
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Integration of microwave MEMS devices into rectangular waveguide with conductive polymer interposers
- 2013
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 23:12, s. 125020-
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates a novel method of integrating microwave microelectromechanical systems (MEMS) chips into millimeter-wave rectangular waveguides. The fundamental difficulties of merging micromachined with macromachined microwave components, in particular, surface topography, roughness, mechanical stress points and air gaps interrupting the surface currents, are overcome by a double-side adhesive conductive polymer interposer. This interposer provides a uniform electrical contact, stable mechanical connection and a compliant stress distribution interlayer between the MEMS chip and a waveguide frame. The integration method is successfully implemented both for prototype devices of MEMS-tuneable reflective metamaterial surfaces and for MEMS reconfigurable transmissive surfaces. The measured insertion loss of the novel conductive polymer interface is less than 0.4 dB in the E-band (60-90 GHz), as compared to a conventional assembly with an air gap of 2.5 dB loss. Moreover, both dc biasing lines and mechanical feedthroughs to actuators outside the waveguide are demonstrated in this paper, which is achieved by structuring the polymer sheet xurographically. Finite element method simulations were carried out for analyzing the influence of different parameters on the radio frequency performance.
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| 2. |
- Chicherin, Dmitry, et al.
(författare)
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Analog-type millimeter-wave phase shifters based on MEMS tunable high-impedance surface and dielectric rod waveguide
- 2011
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Ingår i: International Journal of Microwave and Wireless Technologies. - : Cambridge University Press and the European Microwave Association. - 1759-0787. ; 3:5, s. 533-538
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Tidskriftsartikel (refereegranskat)abstract
- Millimeter-wave phase shifters are important components for a wide scope of applications. An analog-type phase shifter for W-band has been designed, analyzed, fabricated, and measured. The phase shifter consists of a reconfigurable high-impedance surface (HIS) controlled by micro-electromechanical system (MEMS) varactors and placed adjacent to a silicon dielectric rod waveguide. The analog-type phase shift in the range of 0–32° is observed at 75 GHz whereas applying bias voltage from 0 to 40 V to the MEMS varactors. The insertion loss of the MEMS tunable HIS is between 1.7 and 5 dB, depending on the frequency.
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| 3. |
- Chicherin, Dmitry, et al.
(författare)
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MEMS based high-impedance surface for millimetre wave dielectric rod waveguide phase shifter
- 2010
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Ingår i: European Microwave Week 2010, EuMW2010. - 9782874870163 ; , s. 950-953
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Konferensbidrag (refereegranskat)abstract
- Analogue type millimetre wave phase shifter based on a dielectric rod waveguide with adjacent MEMS tuneable high-impedance surface is proposed. Applying bias voltage to the MEMS varactors of the high-impedance surface allow controlling its effective impedance and consequently the phase factor of the propagation constant inside the waveguide. The measured phase difference between the phase shifter with adjacent high-impedance surface and phase shifter with low impedance surface is up to 378°. The insertion loss of the high-impedance surface as phase shifting element at 80-90 GHz is 0.5-2.7 dB depending on the distance to the dielectric rod waveguide.
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| 4. |
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| 5. |
- Chicherin, Dmitry, et al.
(författare)
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MEMS tunable metamaterials surfaces and their applications
- 2010
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Ingår i: APMC 2010. - 9781424475902 - 9784902339215 ; , s. 239-242
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Konferensbidrag (refereegranskat)abstract
- Microelectromechanical systems (MEMS) are proposed as a technological solution for fabrication of metamaterials. This enables tunability of metamaterials effective properties and allows using metamaterials in wide range of applications. Low loss of the MEMS devices allows the metamaterials application to be extended to millimeter and submillimeter wave frequencies without compromising on performance. Electronic beam steering by MEMS tunable metamaterials at millimeter wavelength is considered and a prototype of a W band analog tunable phase shifter is demonstrated. The insertion loss of the fabricated MEMS tunable metamaterials surface varies from 0.7 dB to a maximum of 3.5 dB (at a resonance frequency). MEMS varactors have shown reliable and repeatable analog operation over 108 cycles.
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| 6. |
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| 7. |
- Shah, Umer, et al.
(författare)
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Multi-Position RF MEMS Tunable Capacitors Using Laterally Moving Sidewalls of 3-D Micromachined Transmission Lines
- 2013
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Ingår i: IEEE transactions on microwave theory and techniques. - : IEEE Press. - 0018-9480 .- 1557-9670. ; 61:6, s. 2340-2352
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel concept of RF microelectromechanical systems (MEMS) tunable capacitors based on the lateral displacement of the sidewalls of a 3-D micromachined coplanar transmission line. The tuning of a single device is achieved in multiple discrete and well-defined tuning steps by integrated multi-stage MEMS electrostatic actuators that are embedded inside the ground layer of the transmission line. Three different design concepts, including devices with up to seven discrete tuning steps up to a tuning range of 58.6 to 144.5 fF, (C-max/C-min = 2.46) have been fabricated and characterized. The highest Q factor, measured by a weakly coupled transmission-line resonator, was determined as 88 at 40 GHz and was achieved for a device concept where the mechanical suspension elements were completely de-coupled from the RF signal path. These devices have demonstrated high self-actuation robustness with self-actuation pull-in occurring at 41.5 and 47.8 dBm for mechanical spring constants of 5.8 and 27.7 N/m, respectively. Nonlinearity measurements revealed that the third-order intermodulation intercept point (IIP3) for all discrete device states is above the measurement-setup limit of 68.5 dBm for our 2.5-GHz IIP3 setup, with a dual-tone separation of 12 MHz. Based on capacitance/gap/spring measurements, the IIP3 was calculated for all states to be between 71-91 dBm. For a mechanical spring design of 5.8 N/m, the actuation and release voltages were characterized as 30.7 and 21.15 V, respectively, and the pull-in time for the actuator bouncing to drop below 8% of the gap was measured to be 140 mu s. The mechanical resonance frequencies were measured to be 5.3 and 17.2 kHz for spring constant designs of 5.8 and 27.7 N/m, respectively. Reliability characterization exceeded 1 billion cycles, even in an uncontrolled atmospheric environment, with no degradation in the pull-in/pull-out hysteresis behavior being observed over these cycling tests.
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