R.R. Mansour

University of Waterloo, Ватерлоо, Ontario, Canada

Are you R.R. Mansour?

Claim your profile

Publications (197)156.8 Total impact

  • M. Azizi, N. Sarkar, R.R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: We present the design, fabrication and experimental validation of an integrated Scanning Microwave Microscopy (SMM)/Atomic Force Microscopy (AFM) system that does not require the use of a conventional laser-based AFM. Microfabricated SMM probes are collocated with piezoresistive strain-based sensing AFM probes in a CMOS-MEMS process, and are actuated by integrated electrothermal scanners. Integration of AFM enables dual mode imaging (topography and electrical properties) and more importantly, it enables control over tip-sample distance, which is crucial for accurate SMM imaging. This design is unique in the sense that the tip can be scanned over the sample in 3 degrees of freedom, over a 20 μm×10 μm×30 μm scan range in the x, y, and z directions respectively. We fabricate our device by using a standard foundry CMOS process followed by in-house maskless MEMS post processing to release the devices. Single-chip SMM/AFM devices with integrated 1-D and 3-D actuation are thus obtained. These devices can be used to modulate the tip-sample separation to underlying samples with a periodic signal, improving immunity to long-term system drifts. We also investigate the effect of tip-sample separation on the resolution of the instrument. To increase measurement sensitivity, a single-stub matching network has been used to match the high tip-to-sample impedance to the 50 ohm characteristic impedance of a performance network analyzer. Measurement results of the CMOS-MEMS SMM are presented to verify the proposed concept.
    IEEE Transactions on Microwave Theory and Techniques 12/2013; 61(12):4621-4629. · 2.94 Impact Factor
  • S.S. Attar, R.R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: A dc contact and a capacitive contact niobium-based superconducting radio frequency (RF) microelectro-mechanical systems switches are presented for the first time. The switches are amenable to integration with superconducting-micro-electronics technology. A comparison of the RF performance of the switches at room and cryogenic temperatures indicate a significant improvement in the insertion loss of the switch when niobium is superconducting. A niobium-based dc contact single-port-double-throw switch is designed, fabricated, and tested. Two types of switched capacitor banks are also designed each implementing one of the two types of the introduced switches. The measured results of the capacitor bank with capacitive contact switches show variation of the capacitance value from 0.4 to 0.94 pF. The measured results of the capacitor bank with dc contact switches show variation of the capacitance value from 0.2 to 1 pF at 4 K.
    IEEE Transactions on Applied Superconductivity 06/2013; 23(3):1800104-1800104. · 1.32 Impact Factor
  • S. Setoodeh, R.R. Mansour, D. Gupta
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel high-temperature superconducting (HTS) microstrip K-band filter is designed, fabricated, and measured. The Chebyshev filter has five poles and is designed for the center frequency of 20.45 GHz with a percentage bandwidth of 2.5%. The proposed miniaturized resonator minimizes the unwanted coupling between nonadjacent resonators, which is typically pronounced at high frequencies. The layout is patterned on a 0.5-mm-thick MgO substrate. The dimension of the fabricated filter is 7.5 mm × 3 mm. The filter employs a via-less Coplanar Waveguide to microstrip transition and the layout is configured to allow ease of adjusting and tuning. The filter with via-less Coplanar Waveguide input/output pads is measured in an RF cryogenic probe station at 77 and 4 K to investigate variation of center frequency with operating temperatures. Simulation and measured results of the filter show a spurious-free response up to 35 GHz.
    IEEE Transactions on Applied Superconductivity 06/2013; 23(3):1500404-1500404. · 1.32 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a novel RF-MEMS dielectric-less switched capacitor that exhibits a high capacitance ratio. The proposed design is based on a floating contact element concept that results in a reduced up state capacitance. The switched capacitor was fabricated on 200 mm silicon wafer with an industrial process developed for manufacturing robust and reliable packaged RF MEMS devices. RF Measurements up to 20 GHz were performed on the fabricated device, showing a capacitance ratio higher than 30:1 with a good quality factor over the operating frequency range. This RF MEMS switched capacitor is suitable for adaptive and reconfigurable RF circuits.
    Microwave Integrated Circuits Conference (EuMIC), 2013 European; 01/2013
  • N. Sarkar, G. Lee, R.R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: We present the first imaging results with a dynamic FM-AFM (frequency modulation atomic force microscope) on a chip. This instrument does not require any off-chip scanning hardware or position sensors. The CMOS-MEMS dynamic FM-AFM includes 3-D electrothermal actuation, 3-axis position sensing, and a flexural resonant cantilever with balanced piezoresistive detection, all integrated on a single chip. Several design principles are applied to reduce the instrument's sensitivity to electrical and thermal coupling effects. To the best of the authors' knowledge, this is the first integrated dynamic FM-AFM that can image a sample independently.
    Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII), 2013 Transducers & Eurosensors XXVII: The 17th International Conference on; 01/2013
  • Source
    M. Bakri-Kassem, R.R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel CPW based phase shifter that relies on automatic collapse of capacitive switches is designed, fabricated and tested. The novel design of the phase shifter is due to a novel CPW topology and automatic collapse mechanical design that is designed to operate at several and gradual collapse voltages. The novelty of the CPW has been achieved through the corrugated grounds to create a slow wave transmission line. The resulted compact CPW will have an effective electrical length that is physically equivalent to a relatively longer conventional CPW. The automatic collapse of the designed capacitive switches comes through deferent lengths of the beams that are carrying those capacitive switches. The worst measured insertion loss and return loss are 1.7 dB and 13 dB, respectively, at 30 GHz with a phase shift of almost 106 degrees. The phase shifter is built on alumina substrate of gold material using UWMEMS process.
    Microwave Integrated Circuits Conference (EuMIC), 2013 European; 01/2013
  • S.N. Nejad, A.A. Fomani, R.R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, several Giant Magneto Impedance (GMI) magnetic sensors have been designed, fabricated, post processed and tested to work in low field intensities (miliTesla range). The sensors are multilayer GMI sensors having CoSiB as GMI material surrounded with two thinner gold layers. The conventional thin film microfabrication process is employed to fabricate the sensors on a glass wafer. A post-processing thermal and magnetic treatment is suggested to magnetize GMI material and enhance performance of the sensors. The suggested post-processing step will decrease fabrication cost of GMI sensors and improve their performance effectively.
    Sensors, 2013 IEEE; 01/2013
  • Source
    M. Bakri-Kassem, R.R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel latching RF MEMS Switch is proposed. The single pole single throw (SPST) switch is built on a 20 μm thick nickel layer eliminating any potential warping due to thermal mismatch. The switch exhibits a 40 μm displacement with a power consumption of 175 mW at 80K under vacuum. The measurement was done over ambient and vacuum and over wide range of temperatures from 300 K to 80 K. The switch demonstrates an excellent RF performance up to 26 GHz.
    Microwave Integrated Circuits Conference (EuMIC), 2012 7th European; 01/2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: Out-of-plane Micro-Power Generators (MPG) are investigated to identify their optimal design and operating conditions. Those MPGs employ a variable capacitor, an electret layer embedded between its electrodes, and an inertial mass carried by a movable electrode. Using a linear model, we study the impact of varying the capacitor gap, load resistance, and electret voltage on the output power. In addition, we analyze the effect of squeeze-film damping on the MPG performance. We find that the linear model breaks down as the excitation level increases. A nonlinear model is developed to capture the MPG response and estimate its output power in closed-form.
    IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society; 01/2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: Mass and volume of the payload electronics are significant contributors to the overall cost of space systems. Satellite systems rely on switch matrices to provide system redundancy and to enhance capacity by providing flexible interconnectivity. The RF-MEMS technology offers the potential of large reductions in the mass and volume of satellite switch matrices leading to a significant cost reduction of satellite systems. The technology has also the potential of accelerating the development and implementation of new advanced satellite systems. This paper presents various configurations for highly miniature RF MEMS switch matrices. It also presents novel configurations for high power multiport waveguide switches that eliminate the need to use bulky motors.
    Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International; 01/2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: We present the design and experimental results of a scanning microwave microscopy (SMM) system that does not require the use of a conventional atomic force microscope (AFM). Microfabricated SMM probes are actuated by integrated MEMS scanners in a commercially available multi-user process. This design is unique in the sense that the tip can be scanned over the sample both laterally and vertically, over a 10µm × 10µm scan range. We first validate our approach with a test-bench consisting of a fixed probe and an integrated sample-scanning stage. This device is used to obtain characteristic approach curves of S11 as a function of tip-sample separation. We then investigate the effect of tip-sample separation on the resolution of the instrument. CPW probes with integrated 1-D and 2-D actuation are then presented. These devices can be used to modulate the tip-sample separation to off-chip samples with a periodic (200Hz) signal, improving immunity to long-term system drifts. To increase measurement sensitivity, a single-stub matching network has been used to match high tip to sample impedance to the 50 ohm of a performance network analyzer. Measurement results agree very well with reported SMM measurements in the literature
    Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International; 01/2012
  • S.S. Attar, S. Setoodeh, R.R. Mansour, D. Gupta
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel niobium-based superconducting DC-contact RF MEMS switch is presented for the first time. The switch is amenable to integration with the superconducting micro-electronics (SME) technology. A comparison of the switch RF performance at room and cryogenic temperatures indicates a great improvement in the insertion loss of the switch when niobium is superconducting. The mechanical characteristic of the switch at extremely low temperature (4K) is investigated. The switch exhibits only 18% increase in the actuation voltage as temperature changes from room temperature (300K) to 4K. A niobium superconducting tunable resonator is designed and fabricated employing the proposed switch as the tuning element. The concept can be extended to realize a high-Q switched capacitor bank for reconfigurable RF front-end components in SME receivers.
    Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International; 01/2012
  • J.A. Ruiz-Cruz, M.M. Fahmi, R.R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel combline resonator is introduced in this paper for realizing compact microwave dual-band filters. The basic resonator is based on the well-known combline topology, where an additional metallic conductor is introduced for having two TEM modes. The resonant frequencies of the two asynchronous TEM resonant modes are controlled by the length of the two concentric conductors and their spacing. The proposed structure is employed to realize a dual-band filter, where each combline resonator provides one resonant mode per pass-band. The control of the filter parameters, such as pass-band bandwidths and band separation, is addressed. These filters harness the advantages of combline technology for dual-band filters, using the compactness provided by the proposed resonator. A complete design is introduced. Simulations as well as experimental results are presented showing excellent agreement, thus validating the proposed concept.
    Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International; 01/2012
  • N. Sarkar, K. Trainor, R.R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: The authors report on the operation of complementary metal-oxide semiconductor microelectromechanical system (MEMS) scanning probe microscope (SPM) with integrated three-dimensional electrothermal actuation and three-axis position sensing. Conventional SPM makes use of piezoelectric positioning systems which are bulky (leading to thermal drift and poor vibration immunity) and suffer from inherent creep (leading to image distortion). The scanner design is intended to leverage the myriad physical benefits of dimensional scaling to improve the performance and to reduce the barrier to entry for SPM ownership when compared to the state-of-the-art. However, the integration of multiple electrothermal actuators on chip introduces several complications owing to coupling between electrical, thermal and mechanical domains. The focus of this Letter is to discuss the origins of these effects, and the strategies that are implemented to mitigate them. Specifically, the authors discuss the open-loop and closed-loop control methods that are used to drive the lateral and vertical actuators and propose and verify a method to compensate for the parasitic effects observed in the piezoresistive force sensors. To the best of the authors' knowledge, this is the first integrated MEMS-SPM with multiple imaging modes that can image a sample without the need for off-chip scanners or laser-based position sensing.
    Micro & Nano Letters 01/2012; 7(4):297-300. · 0.80 Impact Factor
  • M. Daneshmand, R.R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: Microelectromechanical systems (MEMS) technology has the potential of replacing many of the radio frequency (RF) components used in to day's satellite communication systems. In many cases, such RF MEMS components would not only substantially reduce size, weight, and power consumption, but also promise superior performance when compared to that of current technologies. The benefits of MEMS technology be come more pronounced for switch matrices because there is a large number of switching elements and, therefore, any size and mass reduction would have large overall impact. Though there has been some controversy on the reliability and lifetime of RF MEMS switches, significant improvements have been made and RF switches with billions of switching cycles have been demonstrated. This article describes the potential applications of RF MEMS switch matrices in the satellite industry, where mass reduction and performance improvement is crucial.
    IEEE Microwave Magazine 09/2011; · 1.67 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A waveguide circular polarizer with reconfigurable polarization sense is proposed in this paper. The polarizer can be switched between right and left hand circular polarization. The polarization sense is controlled by RF MEMS switches, which commute between two states for allowing or blocking adequately two different signal paths inside the waveguide structure. The polarizer is made up of three building blocks, involving E-plane waveguide MEMS SP2T switch, ridge to waveguide transitions and a septum-orthomode transducer. A switchable Ku-band polarizer prototype is designed and tested as a proof of concept. The experimental performance shows acceptable return losses and axial ratio levels in the 12.7 to 14.8 GHz band (15.3% fractional bandwidth). The proposed structure is compact and is useful for applications that require fast polarization switching.
    Microwave Symposium Digest (MTT), 2011 IEEE MTT-S International; 07/2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: Compact components for radio frequency (RF) front-ends realised in low-temperature co-fired ceramics (LTCC) are presented. The aim of this study was to highlight recent advances in realisation of different components for modern RF/microwave subsystems, stressing such attributes as compactness, wide bandwidth and operation in multiple bands. Two key components of every RF front-end are filters and couplers. To illustrate the feasibility of using LTCC technology to realise these components, several designs of filters and couplers are presented. Very compact LTCC ridge waveguide filter covering the whole US ultra-wide band is first discussed, followed by a dual-band LTCC ridge waveguide filter. Two types of wide-band couplers are shown: ridge waveguide couplers realised in LTCC and empty metallic waveguide and also a strip-line LTCC coupler. A common characteristic that will be shown is that the presented components by the authors are modelled using computer-aided design tools based on modal analysis for waveguides as well as commercially available finite-element tools. The shown examples have simulation results compared by different methods as well as some experimental results in LTCC and empty metallic waveguide, used to demonstrate the proposed approach.
    IET Microwaves Antennas & Propagation 07/2011; · 0.97 Impact Factor
  • Fengxi Huang, Siamak Fouladi, R. R. Mansour
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents the design and implementation of a new class of high-Q tunable dielectric resonator (DR) filters based on microelectromechanical systems (MEMS) switches. The use of MEMS switches results in the compact implementation of the proposed filter with near to zero DC power consumption for tuning and high tuning speed. The filter consists of two disk shape dielectric resonators with circular holes created in the center of each resonator. An initial prototype of the filter is assembled. The filter operates in TME mode at a center frequency of 4.8 GHz with a bandwidth of 21 MHz. Measurement results of this prototype demonstrate a tuning range of 160 MHz while the quality factor ranges from 1200-510 over the tuning range. The proposed tuning approach is applicable to other modes of dielectric resonator filters.
    IEEE MTT-S International Microwave Symposium digest. IEEE MTT-S International Microwave Symposium 06/2011;
  • N. Sarkar, R. R. Mansour, O. Patange, K. Trainor
    [Show abstract] [Hide abstract]
    ABSTRACT: We present a CMOS-MEMS atomic force microscope (AFM) with integrated 3-D MEMS actuation and 3-axis position sensing. CMOS driving and sensing electronics have been integrated in the same fabrication process. Our goal is to replace piezoelectric positioning systems which are bulky (leading to thermal drift and poor vibration immunity) and suffer from inherent creep (leading to image distortion). As such, the focus of this work is to leverage the myriad physical benefits of dimensional scaling to improve performance when compared to a conventional AFM. To the best of the authors’ knowledge, this is the first integrated MEMS-AFM that can image a sample without the need for off-chip scanners or laser-based position sensing.
    01/2011;
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents the results of a comprehensive study on the performance of RF MEMS devices at cryogenic temperatures. More than 50 shunt capacitive RF MEMS switches are tested at room temperature (294 K) and liquid nitrogen temperature (77 K). The switches have various supports. The variation of the actuation voltage of each switch at room and cryogenic temperatures is investigated by mechanical simulation. The results show that the type of supports significantly affects the switch actuation voltage. In fact, depending on the shape of the supports the actuation voltage can decrease or increase at cryogenic temperatures. The hypothesis obtained from the analysis of the gold-based RF MEMS devices is confirmed by testing superconducting niobium-based RF MEMS devices, at liquid helium temperature (4 K). The RF performance of a capacitive shunt niobium-based RF MEMS switch and a niobium-based RF MEMS varactor show significant improvement of the insertion loss of the switch and an enormous enhancement of the quality factor of the varactor.
    Microwave Conference (EuMC), 2011 41st European; 01/2011

Publication Stats

2k Citations
156.80 Total Impact Points

Institutions

  • 1998–2013
    • University of Waterloo
      • Department of Electrical & Computer Engineering
      Ватерлоо, Ontario, Canada
  • 2009
    • University of Regina
      Regina, Saskatchewan, Canada
  • 2008–2009
    • University of New South Wales
      • School of Electrical Engineering and Telecommunications
      Kensington, New South Wales, Australia
    • University of Valencia
      Valenza, Valencia, Spain
  • 1989–2008
    • COM DEV International Ltd.
      Cambridge, Ontario, Canada
  • 2004
    • National Research Council Canada
      • Institute for Microstructural Sciences (IMS)
      Ottawa, Ontario, Canada
  • 2002
    • Universität Bremen
      Bremen, Bremen, Germany
  • 2001
    • Canadian Space Agency
      Ottawa, Ontario, Canada
  • 1995–1996
    • University of Maryland, College Park
      • Department of Electrical & Computer Engineering
      College Park, MD, United States