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Printed Circuit Board (printed + circuit_board)

Distribution by Scientific Domains

Engineering	56%
Polymers and Materials Science	30%
Chemistry	6%
2 Other Domains	8%

Selected Abstracts

Printable Electronics: Foldable Printed Circuit Boards on Paper Substrates (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 1 2010
Mater.
Lightweight and flexible printed circuit boards (PCBs) have been produced by micro-patterning metal on paper substrates, as reported by Siegel et al. on page 28. Paper-based electronic devices can be folded and creased repeatedly, shaped to form three-dimensional structures, integrated with paper-based microfluidic devices, and disposed of by flame (as shown in the cover image). [source]

Foldable Printed Circuit Boards on Paper Substrates

ADVANCED FUNCTIONAL MATERIALS, Issue 1 2010
Adam C. Siegel
Abstract This paper describes several low-cost methods for fabricating flexible electronic circuits on paper. The circuits comprise i) metallic wires (e.g., tin or zinc) that are deposited on the substrate by evaporation, sputtering, or airbrushing, and ii) discrete surface-mountable electronic components that are fastened with conductive adhesive directly to the wires. These electronic circuits,like conventional printed circuit boards,can be produced with electronic components that connect on both sides of the substrate. Unlike printed circuit boards made from fiberglass, ceramics, or polyimides, however, paper can be folded and creased (repeatedly), shaped to form three-dimensional structures, trimmed using scissors, used to wick fluids (e.g., for microfluidic applications) and disposed of by incineration. Paper-based electronic circuits are thin and lightweight; they should be useful for applications in consumer electronics and packaging, for disposable systems for uses in the military and homeland security, for applications in medical sensing or low-cost portable diagnostics, for paper-based microelectromechanical systems, and for applications involving textiles. [source]

A Customizable Instrument for Measuring the Mechanical Properties of Thin Biomedical Membranes

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2005
Gracián Triviño
Abstract Summary: A customized instrument has been developed as part of multidisciplinary research work relating to the development of a biodegradable vascular scaffold. This instrument aims to measure the mechanical properties of elastic and viscoelastic thin membranes with tissue engineering applications. Uniform and omni-directional pressure is applied on the whole membrane which is uniformly clamped and submerged into a liquid medium. The mechanical testing described in this study is focused on the stress-strain curves of polycaprolactone (PCL) films after different treatments. The influence of Dulbecco's modified Eagle's culture medium, L929 fibroblast culture, NaOH treatment and film thickness on the mechanical properties of PCL films was evaluated after different times. These studies show that the PCL degradation process is influenced by immersion in the culture medium, inducing an increment in the slope of the pressure-dilation curve which is indicative of an increase in the polymer stiffness. On the other hand, long NaOH treatments make PCL films have more flexible behavior. A computerized version of the instrument: (1) Electrical compressor; (2) Filter; (3) Voltage-pressure converter; (5) Pressure sensor; (6) Differential pressure sensor; (7,8) Main and auxiliary pipettes; (9) Printed circuit board; (10) Personal computer. [source]

A pulse programmer for nuclear magnetic resonance spectrometers

CONCEPTS IN MAGNETIC RESONANCE, Issue 2 2007
C.C. Odebrecht
Abstract A pulse programmer (PP) designed to control a nuclear magnetic resonance (NMR) spectrometer is reported on. The heart of the PP is a computer programmable logic device (CPDL) that provides flexibility to the design and, at the same time, reduces the number of electronics components needed and the dimensions of the printed circuit board. The PP works as follow: first, a pulse sequence defined by a set of instructions is loaded into the RAM memory of the PP. Then, when the process is started, the instructions are, one by one, read, decoded, and executed. Four types of instructions (functions) were defined: PRINT A, PRINT B, WAIT, and STOP. PRINT A and PRINT B change the status of the output channels A and B, respectively, WAIT generates a time delay, and STOP terminates the sequence. The output ports A and B have 14 channels each, and the shortest pulse and resolution are both 200 ns. The design of the PP is versatile, and new functions can be added through software without modifying the printed circuit board. To control the PP from a personal computer, a program named PulseJr was developed. It contains a graphical user interface (GUI) and pulse sequences can be drawn on the monitor screen with the mouse of the computer. Once the pulse sequence is sketched, clicking a button the program compiles the pulse sequence, generates the set of instructions, loads them into the RAM memory of the PP, and starts the pulse sequence. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 127,131, 2007. [source]

Label-Free and Ultra-Low Level Detection of Salmonella enterica Serovar Typhimurium Using Electrochemical Impedance Spectroscopy

ELECTROANALYSIS, Issue 20 2009
Jeffrey
Abstract An immunosensor for rapid and low level detection of the bacterial pathogen Salmonella enterica Serovar Typhimurium was designed and developed based upon label-free electrochemical impedance spectroscopy and correlated to viable cell counts. The immunosensor was fabricated by electroplating gold onto a disposable printed circuit board (PCB) electrode by immobilizing monoclonal antibody (MAb) specific against Salmonella typhimurium cell surface lipopolysaccharide (LPS) onto the surface of the electrode. Use of mass-fabricated and electroplated PCB electrodes allowed for disposable, highly sensitive, and rapid detection of Salmonella in an aqueous environment. Results demonstrate that in purified solution, Salmonella can be detected as low as 10 CFU in a 100,,L volume and label-free and rapid manner in fewer than 90,s. The cost effective approach described here can be used for detection of pathogens with relevance for healthcare, food, and environmental applications. [source]

Evaluation of a digital camera image applied to PCB inspection

HUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 4 2008
Bernard C. Jiang
Rapid advancement and widespread digital camera applications have made it possible to replace charge-coupled device (CCD) cameras in automatic inspections for industrial applications. However, most digital camera applications using the automatic exposure mode may not be effective in some of the inspection environments. The reflection from a board surface in printed circuit board (PCB) inspections is one such problem area. The objective of this study is to develop a methodology to evaluate the effectiveness of using digital cameras for inspection. The indices used for evaluating digital camera image quality are the perceived image quality, the visual resolution, and the noise. An experiment was designed and conducted to determine the optimal camera parameter combination for attaining the best image quality. The desirability function was used to compare various digital camera parameter settings in considering three image quality indices for selecting the best camera-operating conditions. Based on the developed model and the subjective image quality index, the overall image quality improved 9.4% and 13.86%, respectively. The developed methodology can be used to: (a) determine the digital camera image quality, (b) provide an improved model for determining the automatic exposure setting for digital camera designers, and (c) adjust the digital camera parameters for automatic inspection. © 2008 Wiley Periodicals, Inc. [source]

Numerical analysis on thermal characteristics for chip scale package by integrating 2D/3D models

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 1 2009
Ping Yang
Abstract The objective of this paper is to investigate stress and strain of a special scale package-substrate on chip for reliability evaluation or manufacture strategy in deep-seated situation. A two-dimensional model with one-half of cross-section (2D model) and a three-dimensional model with one-fourth of whole package (3D model) were built, respectively, to simulate the thermal stress and strain of CSP-SOC under the condition of the standard industry thermal cycling temperature ,40 to125°C. The different locations can be processed by using the two models, respectively, based on different modeling simplified modes. By using 2D model, the numerical simulation shows that the maximum deformation of the prototype occurs in printed circuit board (PCB), the maximum stress and strain occurs in the outer solder balls. In the meantime, by the results of 3D model, the simulation shows that the maximum elastic strain occurs in the interface between the solder balls and PCB, the minimum strain occurs in the underfill tape, the maximum packaging stress occurs in the edge area of the chip. The result from 3D model maybe more impersonal to reflect the stress and strain characteristics because the third direction is considered in modeling. The analysis by integrating the 2D model and 3D model can get a more comprehensive profile for the thermal investigation of chip scale package (CSP) than by using any single model. The investigation built a basis for improving reliability in engineering design of CSP product. Copyright © 2008 John Wiley & Sons, Ltd. [source]

A flexible RF transmitter module based on flexible printed circuit board by using micro-machining fabrication process

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2010
Seong-Sik Myoung
Abstract This article presents a flexible RF transmitter module based on flexible printed circuit board (FPCB). The polyimide with micro-machining fabrication technique is employed for realization of FPCB to achieve the high flexibility as well as low loss at microwave frequency band. The active devices in the proposed flexible RF transmitter are design with InGaP/GaAs hetero-junction bipolar transistor monolithic microwave integrated circuit process, and the passive devices such as the filter and interconnection lines are fully integrated on the FPCB board to avoid use of external off-chip components for maximized flexibility. The FPCB transmitter module is designed for a short-distance sensor network based on OFDM communication system, and the measured conversion gain and error vector magnitude of the fabricated flexible transmitter are 27 dB and ,32 dB, respectively. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2636,2639, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25572 [source]

Adding microstrip line at the bottom of PCB for enhancing antenna bandwidth

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2010
B.-G. Cho
Abstract In this article, added microstrip line at the bottom area of printed circuit board (PCB) is proposed for improving the bandwidth of GSM900, DCS1800, and PCS1900. By printing the microstrip line at the bottom area of PCB, frequency bandwidth of slim-type cellular phone which has a low-profile monopole antenna is improved. Dimension of the microstrip line is 45 mm × 9 mm. The width and length of the microstrip line is modified for good bandwidth. The measured return loss of the antenna is better than 7.3 dB for low and high band. Measured peak gains of the proposed antenna present 3.41, 5.48, and 5.95 dBi in each band, respectively. Details of the antenna design are described. Its performances are also presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1984,1988, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25399 [source]

Ultra-wideband slot antenna with band-notch characteristics for wireless USB dongle applications

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2009
Deepti Das Krishna
Abstract A compact ultra-wideband (UWB) printed slot antenna is described, suitable for integration with the printed circuit board (PCB) of a wireless, universal, serial-bus dongle. The design comprises of a near-rectangular slot fed by a coplanar waveguide (CPW) printed on a PCB of size 20 × 30 mm2. It has a large bandwidth covering the 3.1,10.6 GHz UWB band, with omnidirectional radiation patterns. Further, a notched band centered at 5.45 GHz wireless local area network bands is obtained within the wide bandwidth by inserting a narrow slot inside the tuning stub. Details of the antenna design are described, and the experimental results of the constructed prototype are presented. The time domain studies on the antenna shows a linear phase response throughout the band except at the notched frequency. The transient analysis of the antenna indicates very little pulse distortion confirming its suitability for high speed wireless connectivity. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1500,1504, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24385 [source]

More stabilized triple-band antenna with a rolled radiating arm and a metallic rod for mobile applications

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2009
Xingyu Zhang
Abstract In this article, a compact design of a flexible planar inverted-F antenna (PIFA) is proposed for triple-band (GSM/DCS/PCS) mobile phone application. The main radiating element of the antenna, which generates the GSM and DCS resonant modes, is printed on a flexible printed circuit board (FPCB) and rolled in a form of cylinder. To improve the construction stability of the antenna, a metallic rod is inserted into the centre of the rolled antenna. The metallic rod acting as a parasitic element of the antenna also generates the PCS resonant mode. The antenna prototype was fabricated and measured. Good agreement between the measurement and simulation results is obtained. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 891,894, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24197 [source]

Resonance shifting and plane impedance calculations for a rectangular cavity in printed circuit board using closed form solutions

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2009
K. Cantrell
Abstract A method for arbitrarily shifting the dominant mode frequency of a rectangular cavity in printed circuit boards (PCBs) is presented. Standard closed-form and analytic solutions are used to determine the frequency, quality factor, and impedance of the cavity. Calculations are compared with 3D full wave finite element method (FEM) solutions. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 452,455, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24080 [source]

Compact multiband slotted antenna for wireless communication applications

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2009
Yi-Chieh Lee
Abstract New design of a compact antenna with slotted structure for multioperating bands of wireless communication systems is presented. By using compact configuration and slot designs on printed circuit board, the proposed antenna has the multiband measured operations for covering the 2.4-GHz WLAN (2.4,2.484 GHz), the WiMAX (IEEE 802.16e in the Taiwan: 2.5,2.69/3.5,3.65 GHz), and the 5-GHz WLAN (5.15,5.35/5.725,5.825 GHz) bands. Several properties of the proposed compact antenna for multiband operation such as impedance bandwidth, radiation pattern, and measured gain have been numerically and experimentally investigated. © 2008 Wiley Periodcals, Inc. Microwave Opt Technol Lett 51: 502,503, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24094 [source]

Switchless bidirectional amplifier for wireless communication systems

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2007
A. Sevinc Aydinlik Bechteler
Abstract A bidirectional amplifier working at 2.4 GHz is presented in this article. The presented amplifier is able to amplify two signals simultaneously. This, since commonly used radio frequency switches are replaced by circulators. The amplifier is designed on a single small-sized printed circuit board. First, the new amplifier circuit is proposed and characterized. Then, its advantages and design problems are analyzed. Finally, design instructions are setup in order to obtain a good performance of the switchless amplifier within the frequency band of interest. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1888,1890, 2007; Published online in Wiley Inter-Science (www.interscience.wiley.com). DOI 10.1002/mop.22631 [source]

Investigation of field variation in multi-pole magnetic components

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 12 2007
Kuo-Chi Chiu
Abstract Using traditional methods, a fine magnetic pole pitch of less than 1 mm was very difficult to achieve and a complicated magnetization system was required. A linear wire circuit pattern was designed and formed on the printed circuit board (PCB) with a periodic structure, which provides a loop allowing the current to flow in opposite directions to induce different magnetic fields among the wire circuit. Correspondingly, a multi-pole magnetic component with a fine magnetic pole pitch of less than 1 mm was accomplished. Various multi-pole magnetic components with different pitch sizes of 400 ,m and 500 ,m were fabricated to investigate the field variation. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Functionalization of Copper Surfaces by Plasma Treatments to Improve Adhesion of Epoxy Resins

PLASMA PROCESSES AND POLYMERS, Issue S1 2009
Juliano Nestor Borges
Abstract Adhesion of epoxy resins on copper foils for printed circuit board (PCB) applications is improved by nearly a factor of 5, using surface cleaning and deposition of a 15-nm-thick film in a low-pressure remote plasma-enhanced chemical vapor deposition process. The cleaning pretreatment, using an N2,O2 oxidizing gas mixture with moderate heating (343 K), gives the best results. This pretreatment removes the carbonaceous contaminants present on the topmost surface of the sample and slightly oxidizes the copper into CuO. This oxide is then reduced during the deposition treatment, presumably by reaction with the aminopropyltrimethoxysilane (APTMS) precursor. The surface roughness is unchanged after treatment, thereby showing that the improvement of the copper/epoxy adhesion is only due to the chemistry of the plasma coating. Applying these results to dielectric barrier discharges allows us to achieve the same level of adhesion, which, therefore, does not depend on the process. [source]

Pyrromethene dye sensitized photopolymer,photochemical behavior in polymer matrix and application to photoresist for printed circuit board

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 5 2006
Shota Suzuki
Abstract The photochemical behavior of the visible light initiating system that consists of a sensitizing dye, 2,6-diethyl-8-phenyl-1,3,5,7-tetramethylpyrromethene BF2 complex (EPP), and a photoacid generator, N -trifluoromethylsulfonyloxy-1,8-naphthalimide (NIOTf), was studied mainly by means of absorption and fluorescence spectrometry not in solution but in a polymer matrix which is a closer medium to the one currently employed in the field of photoresists. Excited singlet electron transfer from EPP to NIOTf was considered as the main reaction pathway in this system. The EPP/NIOTf system was applied to a photoresist for printed circuit board with an appropriate binder polymer which contains an acetal protection group. A pattern profile of the photoresist was exceedingly affected by the amount of photogenerated acids, their diffusion, and amine in the atmosphere. Finally, by controlling exposure energy and the post-exposure bake (PEB) process, a photoresist with a high resolution (8,µm line and space) was obtained under argon ion laser irradiation. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Recycled PCB flour reinforced linear low-density polyethylene composites enhanced by water cross-linking reaction

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2009
Chen-Feng Kuan
Abstract Recycled printed circuit board (PCB) flour reinforced linear low-density polyethylene (LLDPE) composites were prepared successfully. Water cross-linking technique was adopted to improve the physical characteristics of the composites. Composites were compounded using a twin-screw extruder and treated with a coupling agent (vinyltrimethoxysilane, VTMOS) and a compatibilizer (polyolefin elastomer grafted with melaic acid, POE-g-MA). They were then moisture-cross-linked in hot water. The composite that was cross-linked in water exhibited better mechanical properties than the noncross-linked composite because of strong chemical bonding between the filler and the polyolefin matrix. When the PCB flour content reaches 60 wt% following 4 h of water cross-linking, the tensile strength and the flexural strength are increased by 18.8% (12.8,15.2 MPa) and 13.2% (21.9,24.8 MPa) respectively. Scanning electron microscopy (SEM) images of the fracture surfaces of water cross-linked composites indicated that good interfacial strength existed between the filler and the polyolefin matrix. Thermal analyses of water cross-linked composites indicated that the thermal degradation temperature and the heat deflection temperature (HDT) of the composite increased with the increasing of water cross-linking time. The HDT of the composite rose from 55.8 to 83 °C. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

Slit effect of common ground patterns in affecting crosstalk noise between two parallel signal traces on printed circuit boards

ELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 10 2010
Tsuyoshi Maeno
Abstract It is well known that electromagnetic (EM) disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring harnesses from vehicle-mounted printed circuit boards (PCBs) having common ground patterns with slits. To evaluate the noise current outflows from PCBs of this kind, we previously measured noise current outflows from four types of simple three-layer PCBs having two perpendicular signal traces and different ground patterns with or without slits, and showed that slits on a ground pattern allow conducted noise currents to flow out from PCBs, while the levels for the symmetric slit ground type are smaller than in the case of two asymmetric slit ground types. In the present study, to further investigate the above finding, we fabricated six types of simple two-layer PCBs having two parallel signal traces and different ground patterns with and without slits, and measured the crosstalk noise between the traces. We found that the ground patterns with the slits perpendicular to the traces increased the crosstalk noise levels, which were 19 to 42 dB larger than those for the ground pattern with no slits, while the ground patterns with the slits parallel to the traces were able to reduce the noise levels, which were slightly smaller (by 2.5 to 4.5 dB) than in the case of the no-slit ground pattern. These results were confirmed by FDTD simulation, and were also qualitatively explained by means of an equivalent bridge circuit model that we previously proposed. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(10): 19,24, 2010; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10287 [source]

Alkaline leaching of printed circuit board sludge

ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2006
S.H. Hu
Abstract The purpose of this study was to develop a treatment procedure for processing aluminum-contaminated sludge produced from the coagulation/flocculation process of wastewater treatment in the manufacture of printed circuit boards (PCBs). In this study, the reagent sodium hydroxide (2 N) was used to leach the heavy metal sludge and the dissolution of sludge's aluminum content was roughly 70%. The weight loss of the heavy metal sludge was caused by the dissolution of aluminum content of nearly 20%. Although dissolution of a small amount of copper occurred simultaneously during this leaching process, the dissolution of copper content was restricted within 0.72% in the leaching operation and the copper content was concentrated in the residue to increase the copper level. The large amounts of sodium hydroxide and Al3+ remaining in the leachate were recycled as neutralization and coagulation agents in wastewater treatment. Synthetic heavy metal wastewater was neutralized with the preceding leachate to estimate the reuse feasibility of recovered coagulant. The heavy metal concentration of the effluent met regulation standards after neutralization and precipitation. The settling rate could be significantly enhanced by the addition of 100 ppm supplemental polyacrylamide (PAM). © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source]

Printable Electronics: Foldable Printed Circuit Boards on Paper Substrates (Adv. Funct.

Foldable Printed Circuit Boards on Paper Substrates

Influence of water absorption on high-frequency characteristics of insulation layers of printed circuit boards

IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 6 2007
Kaori Fukunaga Member
Abstract The influence of water absorption on complex permittivities of various insulating materials used for printed circuit boards was investigated in the frequency range of K-band (18,26 GHz). Experimental results revealed that the influence of water absorption on complex permittivity, the dielectric loss factor tan,, in particular, was considerably high. For example, the dielectric loss of polyimide film at 85°C, 85% RH became 10 times larger than that at room temperature and humidity. Since the complex permittivities, however, retained the initial values when the specimens are dried, the water in the specimen should exist freely at the internal interfaces of the materials. The increase of permittivity directly affects the performance of printed circuit boards at high frequencies, so that it is important to clarify the influence of water on dielectric properties of insulations. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

High-Dielectric-Constant Silver,Epoxy Composites as Embedded Dielectrics,

ADVANCED MATERIALS, Issue 14 2005
L. Qi
The incorporation of organic-coated silver nanoparticles into an epoxy matrix (see Figure, a,f represent increasing Ag content) results in a flexible 0-3 type nanocomposite with a strikingly high dielectric constant (greater than 300). The composite retains the flexibility and other mechanical properties of the polymer matrix, and may be useful in applications where capacitors are embedded into printed circuit boards. [source]

Prediction of radiated EMI from PCB excited by switching noise of IC

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2009
Hyun Ho Park
Abstract This article describes a methodology to predict radiated emission from the printed circuit boards (PCBs) excited by switching noise of integrated circuits (ICs). Radiation characteristics of PCBs were simulated by using commercial 3D full-wave softwares. IC's switching noise was obtained by measurement. The radiated emission can be calculated by these two factors. To verify the calculation, test PCBs composed of power and ground plane were designed and measured in a 3 m semi-anechoic chamber. The calculated radiated emission showed a good agreement with the measured results. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2262,2266, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24603 [source]