The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform

Jiasheng Hong - One of the best experts on this subject based on the ideXlab platform.

  • recent development of compact microwave filtering structures based on multilayer lcp technology
    Asia-Pacific Microwave Conference, 2012
    Co-Authors: Jiasheng Hong, Francisco Cervera
    Abstract:

    Multilayer Liquid Crystal Polymer (LCP) circuit technology has become very attractive for the development of compact and low-cost planar microwave filters. This paper is aimed to give an overview of recent development of this type of filter. Examples will be given in light of simulated and measured results.

  • miniature quasi lumped element wideband bandpass filter at 0 5 2 ghz band using multilayer Liquid Crystal Polymer technology
    IEEE Transactions on Microwave Theory and Techniques, 2012
    Co-Authors: Shilong Qian, Jiasheng Hong
    Abstract:

    Miniature wideband bandpass filters are proposed using multilayer Liquid Crystal Polymer (LCP) technology to cover the very low-frequency band of 0.5-2 GHz. To reduce the filter size at such low frequencies, lumped-element theory is used for the filter design and a value extraction process is developed to accurately get the capacitive or inductive values of different multilayer microstrip quasi-lumped elements. These elements are used to produce the required filter response, and thus the overall design process relies less on the time-consuming EM optimization. A filter with the size 0.058 λg ×0.026 λg ×0.004 λg is demonstrated as an initial design. To further improve the stopband performance, an improved design is then developed while still maintaining the compact sizes within 0.065 λg ×0.026 λg ×0.004 λg. Both filters are fabricated on a five-metal layer LCP construction, which has not been done before, with robust via connections using the newly developed laser-aided fabrication technique. Good agreements between simulation and fabrication are observed, which has proven both the success of the design methodology, as well as the fabrication technique.

  • highly selective ultra wideband bandpass filters with quasi elliptic function response
    Iet Microwaves Antennas & Propagation, 2011
    Co-Authors: Jiasheng Hong
    Abstract:

    This study presents a new type of compact highly selective ultra wideband (UWB) bandpass filter (BPF) that exhibits a quasi-elliptic function response. By using the quasi-lumped element concept, a broadside coupled resonator is designed to implement a transmission zero at lower stopband, and some shunt resonators are adopted to generate transmission zeros at the upper stopband. Hence, very selective performance with a quasi-elliptic function response is achieved. Two UWB filters are designed for the demonstration. The first filter is designed with a passband from 3.1 to 10.6 GHz for the Federal Communications Commission (FCC)-defined indoor limit application, and the second filter is designed with an even wider passband from 3.0 to 16.2 GHz, showing the flexible wide passband performance of the proposed filters. Experiments are carried out to validate the designs. A low cost multilayer Liquid Crystal Polymer technology is deployed to implement the proposed filters. Small sizes for fabricated filters are achieved, which are 8.8 mm×9.0 mm×0.5 mm and 6.4 mm×5.9 mm×0.2 mm, respectively. All the measured filters have excellent performance, including low insertion losses, flat group delay and high selectivity. The proposed new type of UWB BPF is favourable for practical UWB communication and radar systems.

  • uwb bandpass filter using cascaded miniature high pass and low pass filters with multilayer Liquid Crystal Polymer technology
    IEEE Transactions on Microwave Theory and Techniques, 2010
    Co-Authors: Jiasheng Hong
    Abstract:

    This paper presents a new ultra-wideband (UWB) bandpass filter that is formed by cascading miniature high-pass and low-pass filters implemented with multilayer Liquid Crystal Polymer technology. The miniature high-pass and low-pass filters can be designed independently and the design procedures are described. Experiments are carried out to validate the designs. Small sizes for the fabricated high-pass filter, low-pass filter, and UWB bandpass filter are achieved, which are 4.0 mm × 4.4 mm (0.162 ?g × 0.178 ?g), 4.56 mm × 4.9 mm (0.185 ?g × 0.198 ?g) and 5.1 mm × 8.86 mm (0.207 ?g X 0.359 ?g), respectively, where ?g is the guided wavelength at 6.85 GHz. Excellent performance is obtained for all the measured filters, including low insertion losses and high selectivity. Due to its simple structure and excellent performance, the proposed UWB bandpass filter is favorable for practical UWB communication and radar systems.

  • ultra wideband bandpass filter using embedded stepped impedance resonators on multilayer Liquid Crystal Polymer substrate
    IEEE Microwave and Wireless Components Letters, 2008
    Co-Authors: Zhangcheng Hao, Jiasheng Hong
    Abstract:

    This letter proposes an ultra wideband (UWB) bandpass filter (BPF) based on embedded stepped impedance resonators (SIRs). In this study, broad side coupled patches and high impedance microstrip lines are adopted as quasi-lumped elements for realizing the coupling between adjacent SIRs, which are used to suppress stopband harmonic response. An eight-pole UWB BPF is developed from lump-element bandpass prototype and verified by full-wave simulation. The proposed filter is fabricated using multilayer Liquid Crystal Polymer (LCP) process and measured using vector network analyzer. Good agreement between simulated and measured response is observed. The measurement results show that the fabricated filter has a low insertion loss of 0.18 dB at center frequency 6.05 GHz, an ultra wide fractional bandwidth of 127.3% and excellent stopband rejection level higher than 32.01 dB from 10.9 to 18.0 GHz.

J Papapolymerou - One of the best experts on this subject based on the ideXlab platform.

  • d band characterization of co planar wave guide and microstrip transmission lines on Liquid Crystal Polymer
    Electronic Components and Technology Conference, 2013
    Co-Authors: Wasif Tanvee Kha, Cagri A Ulusoy, J Papapolymerou
    Abstract:

    In this paper, for the first time, characterization of planar transmission lines on organic Liquid Crystal Polymer (LCP) substrate in D-Band is presented. Via-less conductor backed co-planar wave guide (CB-CPW) and microstrip lines are designed, fabricated and measured on 2 mil organic LCP substrate. Line-reflect-reflect-match (LRRM) calibration technique was used to measure the fabricated lines, whereas in order to accurately extract line loss and to characterize the substrate, a thru-reflect-line (TRL) calibration was performed. The results have shown excellent RF performance of LCP in the D-band, while the microstrip line exhibits a loss of 0.1755 dB/mm at 110 GHz, with a monotonous increase to 0.331dB/mm at 170 GHz. An almost constant (~2.6) effective dielectric constant is also reported within the whole measurement band.

  • a 60 ghz active receiving switched beam antenna array with integrated butler matrix and gaas amplifiers
    IEEE Transactions on Microwave Theory and Techniques, 2012
    Co-Authors: Chad E Patterson, Wasif Tanveer Khan, George E. Ponchak, J Papapolymerou
    Abstract:

    This paper presents for the first time a 60-GHz receiving switched-beam antenna on organic Liquid Crystal Polymer (LCP) platform. A 4 × 1 quasi-Yagi array is incorporated with a 4 × 4 Butler matrix beamforming network and GaAs low-noise amplifiers on an LCP substrate. The active beam is controlled by GaAs single-pole-double-throw switches to access the four output states of the Butler matrix. The entire 4 × 1 active array is 1.4 cm × 1.75 cm and consumes 1.1 W of dc power. Successful comparisons of the measured and simulated results verify a working phased array with a return loss better than 10 dB across the frequency band of 56.7-63.7 GHz. A comparison of radiation patterns demonstrate beam steering of ±40° with a peak active gain of 27.5 dB. The combined antenna and receiver noise performance at 60 GHz exhibits an estimated merit G/T of -18.6 dB/K and noise figure of 5.4 dB.

  • frequency agile mechanical antenna for low cost millimeter wave applications
    International Symposium on Antennas and Propagation, 2012
    Co-Authors: Y Orlic, Philippe Coquet, Philippe Pernod, Nicolas Tiercelin, B Lacroix, V Preobrazhensky, J Papapolymerou
    Abstract:

    This paper presents for the first time a frequency tunable, mechanical patch antenna on PDMS/LCP for low-cost millimeter-wave applications. A pneumatic actuation system controls the height of the antenna, resulting in an analog tuning in frequency. The antenna is fed with a typical microstrip line coupled through a slot aperture patterned in the ground plane at the back side of a Liquid Crystal Polymer substrate where the antenna is bonded to. The proposed antenna has a measured gain of 8 dBi, a 10-dB bandwidth of 4.8 GHz at 61.75 GHz and a tuning frequency range of 450 MHz. The designed antenna can be easily scaled to fit other millimeter-wave frequency applications.

  • fractal shaped microstrip coupled line bandpass filters for suppression of second harmonic
    IEEE Transactions on Microwave Theory and Techniques, 2005
    Co-Authors: N Kingsley, R Bairavasubramanian, J Papapolymerou, Manos M Tentzeris, Matthew A Morton, Jonggwan Yook
    Abstract:

    In this paper, microstrip coupled-line bandpass filters using a Koch fractal shape are proposed for the first time. These filters are fabricated on a Liquid Crystal Polymer (LCP) substrate for Ku-band. Conventional microstrip coupled-line filters are very popular for RF front ends because they can be fabricated easily. However, their large second harmonic causes the shape of the passband to be asymmetric in the upper band and it worsens the skirt properties. By proper design, the second harmonic of fractal filters can be significantly suppressed through the use of fractal shapes. In this paper, using LCP, the maximum harmonic suppression was almost 42 dB. This type of filter can be used to suppress the second harmonic without any additional devices and regardless of the substrate.

  • Liquid Crystal Polymer lcp a new organic material for the development of multilayer dual frequency dual polarization flexible antenna arrays
    IEEE Antennas and Wireless Propagation Letters, 2005
    Co-Authors: G Dejean, George E. Ponchak, R Bairavasubramanian, D Thompson, Manos M Tentzeris, J Papapolymerou
    Abstract:

    The development of dual-frequency (14 and 35 GHz), dual-polarization microstrip antenna arrays is presented for the first time on Liquid Crystal Polymer (LCP) multilayer technology. Some of the properties of LCP, such as multilayer (three-dimensional) vertical integration capability, good electrical and mechanical properties, and near-hermetic nature, make this substrate a practical choice for the design of low-cost antenna arrays that can be integrated with remote sensing applications operating in the Ku and millimeter-wave frequency bands. This work illustrates the potential of LCP as a low-cost, "all-package" solution for developing compact, flexible, antenna arrays that can be used in future communication and remote sensing systems.

Timothy J White - One of the best experts on this subject based on the ideXlab platform.

  • programmable and adaptive mechanics with Liquid Crystal Polymer networks and elastomers
    Nature Materials, 2015
    Co-Authors: Timothy J White
    Abstract:

    Liquid Crystals are the basis of a pervasive technology of the modern era. Yet, as the display market becomes commoditized, researchers in industry, government and academia are increasingly examining Liquid Crystalline materials in a variety of Polymeric forms and discovering their fascinating and useful properties. In this Review, we detail the historical development of Liquid Crystalline Polymeric materials, with emphasis on the thermally and photogenerated macroscale mechanical responses--such as bending, twisting and buckling--and on local-feature development (primarily related to topographical control). Within this framework, we elucidate the benefits of Liquid Crystallinity and contrast them with other stimuli-induced mechanical responses reported for other materials. We end with an outlook of existing challenges and near-term application opportunities.

  • topography from topology photoinduced surface features generated in Liquid Crystal Polymer networks
    Advanced Materials, 2013
    Co-Authors: Michael E Mcconney, Angel Martinez, Vince P Tondiglia, Kyung Mi Lee, Derrick Langley, Iva I Smalyukh, Timothy J White
    Abstract:

    Films subsumed with topological defects are transformed into complex, topographical surface features with light irradiation of azobenzene-functionalized Liquid Crystal Polymer networks (azo-LCNs). Using a specially designed optical setup and photoalignment materials, azo-LCN films containing either singular or multiple defects with strengths ranging from |½| to as much as |10| are examined. The local order of an azo-LCN material for a given defect strength dictates a complex, mechanical response observed as topographical surface features.

  • photomechanical mechanism and structure property considerations in the generation of photomechanical work in glassy azobenzene Liquid Crystal Polymer networks
    Journal of Materials Chemistry, 2012
    Co-Authors: Nelson V Tabiryan, Timothy J Bunning, Timothy J White
    Abstract:

    Azobenzene-functionalized Polymeric materials have proven capable of shape adaptive responses when irradiated with light. This work focuses on isolating the fundamental differences between the photogenerated mechanical output of glassy, polydomain azobenzene Liquid Crystal Polymer networks (azo-LCN) upon exposure to either UV and blue-green irradiation. Profound differences in the fundamental photochemical mechanism are identified through spectroscopic examination of representative materials before and after irradiation with UV or blue-green light. The photomechanical response is further elucidated in structure-property examination to ascertain the role of crosslink density, azobenzene concentration, and azobenzene connectivity (crosslinked or pendant) on the photomechanical output.

  • light activated shape memory of glassy azobenzene Liquid Crystalline Polymer networks
    Soft Matter, 2011
    Co-Authors: Hilmar Koerner, Timothy J Bunning, Richard A Vaia, Timothy J White
    Abstract:

    Rapidly reconfigurable, adaptive materials are essential for the realization of “smart”, highly engineered technologies sought by aerospace, medicine, and other application areas. Shape memory observed in metal alloys and Polymers (SMPs) is a primary example of shape change (adaptation). To date, nearly all shape adaptations in SMPs have been thermally triggered. A desire for isothermal, remotely cued shape adaptations of SMP has motivated examinations of other stimuli, such as light. Only a few reports document so-called light-activated SMP, in both cases exploiting photoinduced adjustments to the crosslink density of a Polymer matrix with UV light of 365 nm (crosslinking) and <260 nm (decrosslinking). This work presents a distinctive approach to generating light-activated SMP by employing a glassy Liquid Crystal Polymer network (LCN) material that is capable of rapid photo-fixing with short exposures (<5 min) of eye-safe 442 nm light. Here, linearly polarized 442 nm light is used to photo-fix temporary states in both cantilever and free-standing geometries which are then thermally or optically restored to the permanent shape. The combination of thermal and photo-fixable shape memory presented here yields substantial functionality in a single adaptive material that could reduce part count in applications. As a demonstration of the opportunities afforded by this functional material, the glassy, photoresponsive LCN is thermally fixed as a catapult and subsequently used to transduce light energy into mechanical work, demonstrated here in the “photo-fueled” launching of an object at a rate of 0.3 m s−1.

  • a high frequency photodriven Polymer oscillator
    Soft Matter, 2008
    Co-Authors: Timothy J White, Nelson V Tabiryan, Svetlana V Serak, Uladzimir A Hrozhyk, Vincent P Tondiglia, Hilmar Koerner, Richard A Vaia, Timothy J Bunning
    Abstract:

    High frequency and large amplitude oscillations are driven by laser exposure in cantilevers made from a photosensitive Liquid Crystal Polymer.

Richard D Noble - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of a nanoporous lyotropic Liquid Crystal Polymer membrane for the treatment of hydraulic fracturing produced water via cross flow filtration
    Journal of Membrane Science, 2019
    Co-Authors: Sarah M Dischinge, James Rosenblum, Richard D Noble
    Abstract:

    Abstract Current commercial nanofiltration and reverse osmosis membranes are limited in scope and performance due to their physicochemical properties. Desalination of hydraulic fracturing wastewater poses a particular challenge to membrane filtration given the high concentrations of both organic compounds and salts present in these waters. The recently-developed nanoporous, bicontinuous cubic, lyotropic Liquid Crystal, thin-film-composite Polymer membrane (TFC QI membrane), having unique physicochemical properties, enables an alternative treatment of hydraulic fracturing wastewater. Specifically, the TFC QI membrane recovers the organic compounds from this high-salinity wastewater, enabling biodegradation to occur after desalination. However, other performance criteria must be demonstrated for a membrane to reach application. The work presented herein demonstrates the stable performance of the TFC QI membrane during 66 h of cross-flow filtration of hydraulic fracturing produced water. Compared to the commercial NF90 membrane, the TFC QI membrane recovered a larger portion of the organic compounds, had a higher thickness-normalized water flux, and fouled less. The combination of the TFC QI membrane’s selectivity with its reduced fouling propensity makes possible a treatment for hydraulic fracturing wastewater and other complex aqueous streams inaccessible by most commercial membranes, motivating the further study and development of the TFC QI membrane.

  • effect of post Polymerization anion exchange on the rejection of uncharged aqueous solutes in nanoporous ionic lyotropic Liquid Crystal Polymer membranes
    Journal of Membrane Science, 2017
    Co-Authors: Sarah M Dischinger, Michael J Mcgrath, Kimberly R Bourland, Richard D Noble
    Abstract:

    Abstract The selectivity of a bicontinuous cubic, lyotropic Liquid Crystal (LLC) Polymer nanofiltration membrane containing uniform cationic nanopores was manipulated via anion-exchange at the pore wall by soaking the fabricated membranes in aqueous salt solutions. Monovalent organosulfonate anions of various sizes were completely exchanged as the counterion at the pore walls to explore the impact of anion size on uncharged molecular solute rejection and water permeance. It was found that larger organosulfonate anions associated at the pore walls induced a higher rejection of uncharged solutes and a lower water permeance. The change in selectivity of the nanopores was described quantitatively through the calculation of the effective pore radius. The effective pore radius in these modified membranes was found to vary from 0.9±0.2 to 0.55±0.08 nm depending on the resident organosulfonate counterion, demonstrating sub-1-nm resolution in pore size manipulation. An empirical model was used to demonstrate that physicochemical properties (molecular volume and hydrophobicity) of the resident counterion correlate with the observed solute rejection, suggesting that the counterion can be chosen to target a desired membrane performance. The ability to manipulate uniform, nm-sized pores with sub-1-nm resolution via simple anion-exchange offers a new avenue to tailor nanofiltration membrane performance.

  • thin film composite bicontinuous cubic lyotropic Liquid Crystal Polymer membranes effects of anion exchange on water filtration performance
    Journal of Membrane Science, 2014
    Co-Authors: Laine M Carte, Ia R Wiesenaue, Richard D Noble
    Abstract:

    The effects of anion-exchange on the filtration performance of thin-film composite (TFC) membranes with an active layer consisting of a nanostructured, lyotropic (i.e., surfactant) Liquid Crystal (LLC) Polymer were investigated. These TFC LLC membranes are made by the in situ cross-linking of reactive amphiphiles (i.e., surfactants) that self-organize in the presence of glycerol into a type I bicontinuous cubic (QI) phase that contains a uniform, 3D-interconnected pore network lined with tethered cationic moieties and free mobile anions in the pores. In this study, a systematic series of experiments were performed to independently investigate how monovalent cations and anions affect transport in these TFC QI membranes. TFC QI membranes exposed to feed solutions that contain different cations (i.e., Li+(aq), Na+(aq), and K+(aq)) but have the same monovalent anion as the free mobile anion in the membrane (i.e., Br–(aq)) have a constant flux and a high rejection (>98%). When the cation is kept constant (i.e., Na+(aq)) and the anion in the feed is varied (i.e., Cl–(aq), Br–(aq), NO3(aq)–, and I–(aq)) and allowed to partially anion-exchange with the membrane, a high rejection is maintained (≥96%), but the flux significantly changes depending on the anion in the feed solution. The flux of the TFC QI membranes can also be repeatedly be cycled by contacting the membranes with different anions. Control experiments with completely anion-exchanged TFC QI membranes (i.e., with Cl–(aq), Br–(aq), NO3(aq)–, and I–(aq)) showed that the rejection of sodium salts and uncharged organic solutes was virtually the same for all of the completely anion-exchanged membranes. As a whole, these results demonstrate that the flux of these TFC QI membranes can be tuned by changing the anion with little to no change in the rejection performance. The unique performance characteristics of TFC QI membranes may offer advantages over conventional NF and RO membranes for water purification applications or other aqueous separations.

  • water filtration performance of a lyotropic Liquid Crystal Polymer membrane with uniform sub 1 nm pores
    Journal of Membrane Science, 2011
    Co-Authors: Eva S Hatakeyama, Christophe J Gabriel, Ia R Wiesenaue, Jenny L Loh, Meijua Zhou, Richard D Noble
    Abstract:

    Abstract The water filtration performance of a supported, nanostructured, lyotropic (i.e., surfactant) Liquid Crystal (LLC) Polymer membrane containing uniform, sub-1-nm pores was examined in more detail using more extensive aqueous filtration tests and a more structurally representative nanopore model. This nanoporous membrane material is based on the radical cross-linking of an ionic, LLC monomer that forms a type I bicontinuous cubic (Q I ) phase with a 3D interconnected, annulus-like, water pore network. Previously, initial water transport studies using a limited number of solutes demonstrated initial proof-of-concept that this LLC Polymer membrane can reject small molecules based on molecular size discrimination. In this study, more comprehensive transport experiments using aqueous solutions containing a wider range of different size neutral organic molecules and salt ions were undertaken. The results of these experiments showed that the LLC Polymer membrane has a rejection performance in between that of a commercial, high-performance reverse osmosis (RO) membrane (Dow SW30HR) and that of a conventional porous nanofiltration (NF) membrane (Dow NF-270) with non-uniform pore sizes. Specifically, the LLC membrane was found to reject inorganic salt ions much better than a NF membrane, and on a level comparable to a RO membrane. It does not reject small neutral organic solutes as well as a RO membrane, but it was found to reject organic solutes better than a conventional NF membrane. Also, the organic solute rejection behavior was fitted using two different Donnan-steric pore models (DSPM) with different pore shapes (i.e., cylindrical and straight slit). It was determined that the Q I -phase LLC membrane has an effective pore radius between 0.29 nm and 0.45 nm. This modeling also suggested that the LLC nanopores are indeed uniform in size. Initial chemical stability and fouling experiments suggest this nanoporous LLC Polymer membrane is also very resistant to chlorine degradation and protein fouling. This combination of properties makes this nanoporous LLC Polymer a very promising membrane material for water desalination and other NF processes.

John Papapolymerou - One of the best experts on this subject based on the ideXlab platform.

  • large frequency tuning of a millimeter wave antenna using dielectric Liquids in integrated micro channels
    International Microwave Symposium, 2015
    Co-Authors: Gaetan Dufour, Philippe Coquet, Philippe Pernod, Wasif Tanveer Khan, Nicolas Tiercelin, John Papapolymerou
    Abstract:

    In this work, investigation has been made of a planar millimeter wave antenna on microfluidic channels which allow a very large resonance frequency tuning up to 51% (from 16.8 to 28.4 GHz). A microstrip antenna lays over a 12 mil (300 µm) thick Liquid Crystal Polymer (LCP) substrate in which two micro-channels are drilled to be filled with different dielectric Liquids (water, ethanol, methanol, acetone). The two channels are strategically placed under the radiating edges of the patch antenna where the electric field is the strongest. Thus, by changing the Liquid in the channels, the equivalent permittivity of the multilayer structure is locally modified and the resonant frequency of the antenna is strongly tuned.

  • high resolution aerosol jet printing of d band printed transmission lines on flexible lcp substrate
    International Microwave Symposium, 2014
    Co-Authors: Yung Hang Chang, Wasif Tanveer Khan, Kan Wang, Spyridon Pavlidis, John Papapolymerou
    Abstract:

    In this paper, aerosol jet printing technology is assessed for D-band RF applications for the first time. It describes the fabrication process, the technology assessment and the characterization of coplanar waveguides (CPW) lines and CPW to microstrip transitions on Liquid Crystal Polymer (LCP) in the D band using silver nanoparticle aerosol jet printing process. Feature sizes with a resolution of 10 μm, which is the finest resolution among all of the digital printing technologies, were realized successfully. The conductivity of the sintered silver structures was half to that of bulk silver after sintering at temperatures up to 200 °C. Printed transmission lines demonstrated losses of 0.35 dB/mm at 110 GHz and 0.51 dB/mm at 170 GHz that are less than that of the insertion loss of the inkjet printing lines by an order of magnitude.

  • uwb elliptical monopoles with a reconfigurable band notch using mems switches actuated without bias lines
    IEEE Transactions on Antennas and Propagation, 2009
    Co-Authors: Symeon Nikolaou, Nickolas D. Kingsley, Nickolas Kingsley, John Papapolymerou, George E. Ponchak, M.m. Manos M. Tentzeris
    Abstract:

    Two CPW-fed elliptical monopoles were fabricated on Liquid Crystal Polymer (LCP) with reconfigurable rejection band (band-notch) characteristics in the frequency range between 5 and 6 GHz. The first antenna uses a lambda/2 long, U-shaped slot and the second antenna uses two symmetrically placed lambda/4 long, inverted L-shaped stubs as resonating elements. Microelectromechanical system (MEMS) switches are used to activate and deactivate the resonating elements without the need of dc bias lines due to a novel design of the switch geometry. Transmission line models and surface current distributions are used to explain the effect of the added resonating elements. Reflection coefficient radiation pattern and gain measurements are presented to verify the design concepts featuring a very satisfactory performance.

  • Reconfigurable RF MEMS phased array antenna integrated within a Liquid Crystal Polymer (LCP) system-on-package
    IEEE Transactions on Antennas and Propagation, 2008
    Co-Authors: Nickolas Kingsley, George E. Ponchak, John Papapolymerou
    Abstract:

    For the first time, a fully integrated phased array antenna with radio frequency microelectromechanical systems (RF MEMS) switches on a flexible, organic substrate is demonstrated above 10 GHz. A low noise amplifier (LNA), MEMS phase shifter, and 2 times 2 patch antenna array are integrated into a system-on-package (SOP) on a Liquid Crystal Polymer substrate. Two antenna arrays are compared; one implemented using a single-layer SOP and the second with a multilayer SOP. Both implementations are low-loss and capable of 12deg of beam steering. The design frequency is 14 GHz and the measured return loss is greater than 12 dB for both implementations. The use of an LNA allows for a much higher radiated power level. These antennas can be customized to meet almost any size, frequency, and performance needed. This research furthers the state-of-the-art for organic SOP devices.

  • fully canonical pseudo elliptic bandpass filters on multilayer Liquid Crystal Polymer technology
    IEEE Microwave and Wireless Components Letters, 2007
    Co-Authors: R Bairavasubramanian, John Papapolymerou
    Abstract:

    Microstrip pseudo-elliptic bandpass filters, operating in the X-band, have been designed and implemented on multilayer Liquid Crystal Polymer (LCP) technology for the first time. Folded open loop resonators printed on different dielectric surfaces and sharing the same ground plane are coupled through slots etched in the ground plane. Fully canonical filtering and modularity have been achieved through introduction of internal nonresonant nodes. Multilayer configuration is realized through thermocompression bonding of thin sheets of LCP. The designed fourth-order filter exhibits a low insertion loss of 3.2 dB at 9.9 GHz