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Showing papers in "Microwave and Optical Technology Letters in 2013"


Journal ArticleDOI
TL;DR: In this article, a correlation between electrical properties (relative permittivity −er and conductivity −σ) of blood plasma and plasma glucose concentration was found, and the authors developed a single-pole Cole-Cole model for er and σ as a function of plasma blood glucose concentration.
Abstract: In this study, we show a correlation between electrical properties (relative permittivity–er and conductivity–σ) of blood plasma and plasma glucose concentration. In order to formulate that correlation, we performed electrical property measurements on blood samples collected from 10 adults between the ages of 18 and 40 at University of Alabama Birmingham (UAB) Children's hospital. The measurements are conducted between 500 MHz and 20 GHz band. Using the data obtained from measurements, we developed a single-pole Cole–Cole model for er and σ as a function of plasma blood glucose concentration. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1160–1164, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27515

125 citations


Journal ArticleDOI
TL;DR: A reconfigurable wide slot antenna integrated with stepped impedance resonators (SIRs) and ideal switches for ultra wideband (UWB) and multiband communication applications is proposed in this article.
Abstract: A reconfigurable wide slot antenna integrated with stepped impedance resonators (SIRs) and ideal switches for ultra-wideband (UWB) and multiband communication applications is proposed. The proposed reconfigurable antenna can be used as a UWB antenna, a dual notch-band UWB antenna, and multiband antennas. The dual notch-band functions are obtained by using two stepped impedance stub-loaded SIRs. The reconfigurable characteristics are achieved by using two ideal switches on SIRs. The measurement and simulation results show that the proposed reconfigurable antenna has good switchable characteristics and dual notch-band functions. The designed reconfigurable antenna is suitable for future multimode wireless communications systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:52–55, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27253

75 citations


Journal ArticleDOI
TL;DR: In this article, the authors constructed broadband ultra thin absorbers using metamaterials in microwave frequencies (C-band) for lower band surveillance and air defense applications, where the frequencies of absorptions have been brought closer by parametric optimization of electric field driven LC structures to give rise to a higher full width at half maxima (FWHM) bandwidth.
Abstract: The aim of this article is to construct broadband ultra thin absorbers using metamaterials in microwave frequencies (C-band) for lower band surveillance and air defense applications The frequencies of absorptions have been brought closer by parametric optimization of electric field driven LC structures to give rise to a higher full width at half maxima (FWHM) bandwidth The FWHM bandwidth of 042 GHz with 813% has been theoretically observed ranging from 494–536 GHz The structure is fabricated and experimentally tested for the normal incidence of electromagnetic wave inside the anechoic chamber The structure is also investigated for oblique incidence which shows that FWHM bandwidth is maintained upto 40° The structure is also simulated for different angles of polarization where insignificant shift in frequency is noticed as well as FWHM bandwidth is also maintained upto 30° © 2013 Wiley Periodicals, Inc Microwave Opt Technol Lett 55:2131–2137, 2013

66 citations


Journal ArticleDOI
TL;DR: In this paper, a dual-band WLAN/ultrawideband (UWB) printed wide slot microstrip-fed antenna is presented for multi-input multi-output (MIMO)/diversity applications.
Abstract: In this article, a dual-band WLAN/ultrawideband (UWB) printed wide slot microstrip-fed antenna is presented for multi-input multi-output (MIMO)/diversity applications. The proposed antenna consists of a U-shaped patch, a T-shaped monopole path, and a pentagonal wide slot in the ground plane. The antenna is designed to cover both the WLAN (2.4-2.485 GHz) and UWB (3.1-10.6 GHz) ranges, with value of S11 below � 10 dB. The antenna is constructed on a FR4 substrate with overall dimensions of 28 � 28 � 1m m 3 .I t is shown that the proposed dual-band antenna is suitable for diversity polarization applications. The simulation results show that the different configurations of the antenna in the MIMO/diversity have good S- parameters over the operating frequency bands. The simulation and measured results of the proposed dual-band antenna as well as that of the MIMO/diversity antenna configuration agree well. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:461-465, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27391

51 citations


Journal ArticleDOI
TL;DR: In the framework of the multitask Bayesian compressive sensing (BCS) paradigm, two innovative approaches for the solution of coherent imaging problems are proposed within the first‐order Born approximation and the Rytov approximation.
Abstract: In the framework of the multitask Bayesian compressive sensing (BCS) paradigm, two innovative approaches for the solution of coherent imaging problems are proposed within the first-order Born approximation and the Rytov approximation.Selected numerical results are reported to compare the proposed techniques with state-of-the-art BCS approaches as well as global optimization-based methods. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1553–1558, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27612

49 citations


Journal ArticleDOI
TL;DR: An asymmetric coplanar strip (ACS)-fed dual-band antenna using loaded capacitance terminations for 2.4/5.8 GHz wireless local area network applications is studied numerically and verified experimentally.
Abstract: An asymmetric coplanar strip (ACS)-fed dual-band antenna using loaded capacitance terminations for 2.4/5.8 GHz wireless local area network applications is studied numerically and verified experimentally. The proposed antenna consists of two meandered strip radiating elements, two loaded capacitance terminations, an asymmetric ground plane, a shunt inductor, and an ACS-fed structure. Two resonance frequencies are controlled by adjusting the dimensions of the two meandered strip radiator elements and two loaded capacitance terminations. This antenna has small size of 17 × 12 mm2 including the ground plane. Simulation and measurement results show that the proposed antenna can work at dual-band frequencies and has omnidirectional radiation patterns. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2066–2070, 2013

47 citations


Journal ArticleDOI
TL;DR: In this article, a dual-band asymmetric slit with defected ground structure microstrip antenna for circular polarization (CP) operation is proposed, which shows the bandwidth of 7.5% (2.30-2.48 GHz) and 2.94% (3.80-3.9 GHz) at lower and upper bands, respectively.
Abstract: A novel dual-band asymmetric slit with defected ground structure microstrip antenna for circular polarization (CP) operation is proposed. In which, the lower resonant band is excited by cutting asymmetric slit on square microstrip antenna, and a new concept of defected ground with truncated corners structure is used to excite upper resonant band. The antenna is practically fabricated and simulated. Measured results show a good agreement with simulated results. Antenna is compact in size and shows a good quality of polarization at both resonant bands. Antenna shows the bandwidth of 7.5% (2.30–2.48 GHz) and 2.94% (3.80–3.9 GHz) at lower and upper bands, respectively. The antenna also shows 40 and 11 MHz, 3-dB axial ratio bandwidth at lower and upper bands, respectively. The return loss and radiation pattern of the proposed antenna remain consistent for both resonant bands. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1198–1201, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27547

46 citations


Journal ArticleDOI
TL;DR: In this paper, a dual-band (3.5 and 5.8 GHz) meandered monopole antenna for wireless local area network (WLAN)/worldwide interoperability for Microwave Access (WiMAX) applications is proposed, which is fed by an asymmetric coplanar strip.
Abstract: In this article, we present the design of a dual-band (3.5 and 5.8 GHz), meandered monopole antenna for Wireless Local Area Network (WLAN)/Worldwide Interoperability for Microwave Access (WiMAX) applications, which is fed by an asymmetric coplanar strip (ACS). The proposed antenna is comprised of an asymmetric ground plane, an ACS-fed structure, and coupled meandered monopole-type of radiating elements that are designed to provide the two desired operation bands, namely 3.5 and 5.8 GHz. The two resonance frequencies of the antenna can be controlled by adjusting the dimensions of the radiating elements, namely the two meandered monopoles, and the gap between them which controls the coupling. The designed antenna has a small size, which is only 20 × 12 mm2 including the ground plane. Simulated and measured results are presented to demonstrate that the proposed dual-band antenna is well suited for WLAN and WiMAX applications. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2370–2373, 2013

46 citations


Journal ArticleDOI
TL;DR: In this article, a CPW-fed hexagonal-shape monopole-like ultrawideband (UWB) antenna is proposed for UWB applications, which uses a hexagonal shape over the conventional monopole patch antenna to lower the height of the antenna.
Abstract: A novel CPW-fed hexagonal-shape monopole-like ultrawideband (UWB) antenna is proposed for UWB applications. The proposed antenna posses a method to minimize the monopole antenna by using a hexagonal shape over the conventional monopole patch antenna to lower the height of the antenna. The ground is vertically extended toward two sides of the single radiator. Therefore, the large space around the radiator that is usually wasted can be effectively saved. The antenna is practically fabricated and simulated. Measured results show a good agreement with simulated results. The prototype with very compact overall size of 25 × 23 × 1.6 mm3 achieves good impedance matching, stable radiation patterns, and constant group delay over an operating bandwidth of 2.71–12.61 GHz (9.9 GHz). © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2582–2587, 2013

43 citations


Journal ArticleDOI
TL;DR: It is shown that the use of basis functions with edge singularities in the modeling of the current density on the dipoles leads to important computer memory and CPU times savings in the analysis of the periodic structures.
Abstract: Originally published Microwave Opt Technol Lett 55:1212–1216, 2013. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1976, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27739 (Original article DOI 10.1002/mop.27533)

41 citations


Journal ArticleDOI
TL;DR: In this paper, a compact asymmetric coplanar strip-fed staircase ultrawideband (UWB) antenna with notch band reconfigurable characteristic is proposed and investigated numerically and experimentally.
Abstract: A compact asymmetric coplanar strip-fed staircase ultrawideband (UWB) antenna with notch band reconfigurable characteristic is proposed and investigated numerically and experimentally.The reconfigurable notch bands are realized by using a spur-slot and an ideal switch. By controlling the switch at OFF and ON states, the notch bands of the proposed UWB antenna can work at 3.5 and 8.2 GHz, respectively. Numerical and experimental results show that the proposed antenna is capable of working for entire UWB application and providing the reconfigurable notch bands. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1467–1470, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27634

Journal ArticleDOI
Se Hoon Yang1, Deok Rae Kim1, Hyun Seung Kim1, Yong Hwan Son1, Sang-Kook Han1 
TL;DR: An indoor location estimation algorithm that uses the signal extinction ratio distribution of LED‐based visible light communication to improve the positioning accuracy and the received extinction ratio from different LED transmitters is proposed.
Abstract: In this article, we propose an indoor location estimation algorithm that uses the signal extinction ratio distribution of LED-based visible light communication.To improve the positioning accuracy, we use the received extinction ratio from different LED transmitters. In order to mitigate interference between transmitters, a location code was sent using time division multiplexing (TDM). We verified the feasibility of the proposed position estimation algorithm with an experimental demonstration. The proposed algorithm provided positioning accuracy with a 1.5787-cm mean distance error for a given equilateral triangle cell with three 60-cm sides. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1385–1389, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27575

Journal ArticleDOI
TL;DR: In this article, a planar inverted-F antenna is presented for 8-band LTE/WWAN operation (704-960/1710-2690 MHz) in the Ultrabook or thin-profile tablet computer.
Abstract: For eight-band LTE/WWAN operation (704–960/1710–2690 MHz) in the Ultrabook or thin-profile tablet computer, a planar antenna of simple structure and small size is presented. The proposed antenna is obtained by modifying a simple planar inverted-F antenna and can be printed on one surface of a thin FR4 substrate of size 10 × 45 mm2 only. The antenna's lower band bandwidth is greatly widened by embedding a proper chip capacitor of 2.7 pF at the feeding strip. This chip capacitor combines with the antenna's shorting strip can control the excitation of a parallel resonance to modify the impedance matching of the antenna's lower band such that a widened bandwidth is easily obtained to cover the LTE700/GSM850/900 operation. Conversely, the antenna's upper-band bandwidth is also greatly enhanced by using a coupled section in the antenna's radiating strip and adding a parasitic shorted strip near the feeding strip, which lead to multiple resonant modes excited to form a wide bandwidth (>1 GHz) to cover the GSM1800/1900/UMTS/LTE2300/2500 operation. Owing to its small size and simple structure, the proposed antenna is very suitable to be applied in achieving an antenna array with high isolation for MIMO or dual talk (dual WWAN) operation. Promising high-isolation antenna arrays formed by the proposed antennas are presented. The obtained isolation between the antennas in the antenna array is better than 12 dB, and the envelope correlation coefficient is less than 0.15 for frequencies over the LTE/WWAN bands. Details of the proposed antenna and antenna array are presented. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1928–1934, 2013

Journal ArticleDOI
TL;DR: An indoor positioning system based on GPS repeaters and a modified positioning algorithm is proposed, designed, and tested and shows that the proposed system can be used for indoor positioning in locations where there is no GPS signal reception.
Abstract: The Global Positioning System (GPS) is highly reliable and accurate when used outdoors.However, in indoor environments, due to the additional signal loss incurred by the walls of the buildings, the detection and decoding of GPS signals becomes a difficult task. As a solution to the indoor area coverage problem, an indoor positioning system based on GPS repeaters and a modified positioning algorithm is proposed, designed, and tested. A prototype indoor positioning system for 1D/2D positioning is built using directional GPS antennas and low-noise amplifiers (LNA). The modified positioning algorithm is used for the real time processing of captured live GPS data. All the system components are integrated and positioning is obtained for the evaluation of the system performance. Results of the experiments show that the proposed system can be used for indoor positioning in locations where there is no GPS signal reception. The proposed system facilitates the continuation of GPS services indoors with hardware additions to the buildings and only a software update to a standard GPS receiver.

Journal ArticleDOI
TL;DR: In this article, the performance characteristics of passive electrically small antennas with non-Foster elements were investigated and a 300 MHz design was reported, which achieves high radiation efficiencies, high directivities, and large front-to-back-ratios over a 100% fractional bandwidth.
Abstract: Fundamental physics limits the performance characteristics of passive electrically small antennas A 300 MHz design, which includes non-Foster elements and exceeds those limits, is reported It simultaneously achieves high radiation efficiencies (>8163%), high directivities (>625 dB), and large front-to-back-ratios (>2671 dB) over a 100% fractional bandwidth © 2013 Wiley Periodicals, Inc Microwave Opt Technol Lett 55:1430–1434, 2013; View this article online at wileyonlinelibrarycom DOI 101002/mop27587

Journal ArticleDOI
TL;DR: In this article, a 5.6 GHz low-phase noise Colpitts quadrature voltage-controlled oscillator (VCO/QVCO) is presented.
Abstract: A fully integrated, 5.6 GHz low-phase noise Colpitts quadrature voltage-controlled oscillator (VCO/QVCO) is presented. This QVCO is a complementary cross-coupled voltage-controlled Colpitts oscillator with a three-bit switched capacitor array parallel to the inductor to form LC-resonant tank and was implemented in TSMC 0.18 μm CMOS technology with 1.8 V supply voltage. Without buffer circuits, measured results achieve a tunable frequency range from 4.81 to 5.75 GHz, corresponding to 17.8%, a phase noise of −121 dBc/Hz at 1 MHz offset frequency from 5.64 GHz, while the QVCO draws 3.8 mA current and 6.84 mW consumption, respectively. Including pads, the chip area is 1.046 mm2 (1.35 × 0.775 mm2). The output power is −10.04 dBm with 50-Ω termination at the frequency of 5.64 GHz, and the calculated figure of merit is −187.7 dBc/Hz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1490–1493, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27629

Journal ArticleDOI
TL;DR: In this paper, a modified corrugated balanced antipodal Vivaldi antenna with director (CBAVA-D) is presented for ultrawideband (UWB) applications.
Abstract: A modified corrugated balanced antipodal Vivaldi antenna with director (CBAVA-D) is presented for ultrawideband (UWB) applications in this article. The main features of the antenna, besides an UWB width are high gain, low cross-polarization, and excellent group delay. The new antenna concept, including the hybrid structure of exponential tapered corrugation edge and curving dielectric director with high-dielectric constant is demonstrated, based on simulation and measurement results in both frequency and time domain. The antenna prototype input match is better than −10 dB, the maximal gain of 12.6 dB and the cross-polarization level less than −30 dB in the main beam direction at 1.5–15 GHz band are achieved. In the time domain measured group delay with variation less than ±0.25 ns in the whole operating band is also obtained and exhibited. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1321–1325, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27558

Journal ArticleDOI
TL;DR: In this article, a simple I-shaped resonator in between two E-shaped microstrip antenna elements separated by 045λ was proposed to reduce the mutual coupling in patch array of antennas.
Abstract: Mutual coupling is an inevitable phenomenon in multielement antenna systems It can significantly degrade the performance of array systems A number of works have been done on the suppression of mutual coupling in the recent years In this article, we propose a simple I-shaped resonator in between two E-shaped microstrip antenna elements separated by 045λ to reduce the mutual coupling in patch array of antennas The mutual coupling has been reduced by more than 30 dB by the introduction of this simple I-shaped resonator on the same plane of the microstrip radiator We have developed an experimental model that has proven this concept of antenna coupling reduction Finally, the influence of other antenna parameters on the mutual coupling level has been studied One may find its application in wireless communication © 2013 Wiley Periodicals, Inc Microwave Opt Technol Lett 55:2544–2549, 2013

Journal ArticleDOI
TL;DR: A robust and reliable algorithm for computationally efficient design optimization of microwave structures evaluated with electromagnetic (EM) simulations is introduced, using a low‐fidelity model constructed from coarse‐discretization EM simulation of the structure under consideration as well as cheap derivative information obtained by means of adjoint sensitivity.
Abstract: A robust and reliable algorithm for computationally efficient design optimization of microwave structures evaluated with electromagnetic (EM) simulations is introduced. The presented approach utilizes a low-fidelity model constructed from coarse-discretization EM simulation of the structure under consideration, as well as cheap derivative information obtained by means of adjoint sensitivity. Adjoint sensitivity is exploited to reduce the misalignment between the low- and high-fidelity models through input space mapping, to construct a first-order consistent surrogate model through manifold mapping, and to optimize the surrogate through a trust-region-based algorithm. This comprehensive use of adjoint sensitivity results in a very low design cost and excellent convergence capability of the proposed algorithm. Efficiency of our approach is demonstrated using two examples: an ultra-wideband antenna and a microstrip bandpass filter. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:809–813, 2013; View this article online at wileyonlinelibrary.com. DOI: 10.1002/mop.27430

Journal ArticleDOI
TL;DR: In this article, a novel design of a circular patch antenna having Z-shaped defected ground structure is presented for X-band applications, and the antenna is designed for Xband applications.
Abstract: A novel design of a circular patch antenna having Z-shaped defected ground structure is presented in this communication. The antenna is designed for X-band applications. A wideband is obtained in the X-band frequency range 8–12 GHz. The return loss and input impedance is measured experimentally and compared with the simulated results. Parameters like impedance bandwidth, voltage standing wave ratio, and antenna gain are calculated and discussed. Impedance bandwidth of about 1.2 GHz is obtained with a gain of 8.7 dBi and side lobe level of −20.1 dB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2251–2254, 2013

Journal ArticleDOI
TL;DR: In this article, two distinct EBG structures are designed to achieve the two objectives of miniaturization and suppression of interelement coupling due to surface waves in a multiantenna system.
Abstract: In this article, a compact multielement antenna system composing of microstrip patch antennas is designed by using electromagnetic bandgap (EBG) structures. Two distinct EBG structures are designed to achieve the two objectives of miniaturization and suppression of interelement coupling due to surface waves in a multiantenna system. By embedding an EBG array operating in the slow-wave region, the area of the microstrip patch antenna is reduced by 67.48%. To alleviate the resulting increased back radiation, a second EBG structure is designed to surround the miniaturized patch antenna and close to 8 dB improvement in the front-to-back lobe ratio is achieved. As well, the second EBG design is included in a 2 x 2 multiantenna system to suppress interelement coupling. It is found that the coupling is reduced significantly when utilizing the proposed EBG rings. (c) 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:16091612, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27621

Journal ArticleDOI
TL;DR: In this article, a dual-layer frequency selective surface (FSS) was designed as a reflector for UWB antennas, which can be inserted between a planar UWB antenna and a nearby parallel conducting surface such as a circuit board, screen, or a metal case, to isolate them and to prevent antenna impedance mismatch.
Abstract: An ultra-wideband (UWB), dual-layer frequency selective surface (FSS) is presented.This compact low-profile FSS has been designed as a reflector for UWB antennas. It can be inserted between a planar UWB antenna and a nearby parallel conducting surface such as a circuit board, screen, or a metal case, to isolate them and to prevent antenna impedance mismatch otherwise caused by the conductor. The measured transmission coefficient magnitude of the FSS is less than −10 dB over a 133% bandwidth and its reflection phase is appropriate for this and other similar reflector applications, over an UWB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1223–1227, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27583

Journal ArticleDOI
TL;DR: In this paper, a 2 × 2 (four element) and 2 × 4 (eight element) multiple-input-multiple-output (MIMO) antenna systems are designed for the IEEE 802.11ac standard.
Abstract: A highly compact 2 × 2 (four element) and 2 × 4 (eight element) multiple-input-multiple-output (MIMO) antenna systems are designed for the IEEE 802.11ac standard. The antennas operate in the 5-GHz band with a minimum effective bandwidth of 80 MHz. The elements of the MIMO antenna system are patch antennas loaded with complementary split-ring resonators. A minimum isolation of 10.5 dB and maximum gain of −0.8 dBi are measured. Total size of the MIMO antenna systems is 50 × 100 × 0.8 mm3. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1589–1594, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27611

Journal ArticleDOI
TL;DR: In this article, an integrated antenna array comprising two decoupled multiband WWAN/LTE antennas having an isolation ring strip embedded therebetween and all disposed on the same FR4 substrate of small size 10 × 70 mm2 is presented.
Abstract: An integrated antenna array comprising two decoupled multiband WWAN/LTE antennas having an isolation ring strip embedded therebetween and all disposed on a same FR4 substrate of small size 10 × 70 mm2 is presented. The two decoupled antennas cover the 824–960/1710–2690 MHz bands for the GSM850/900 and GSM1800/1900/UMTS/LTE2300/2500 operations and are promising to be mounted at the bottom edge of a smartphone for dual wireless wide area network (WWAN) operation for dual-talk function or for long term evolution (LTE) multiple-input multiple-output operation. The measured transmission coefficient S21 between the two antennas is less than −15 dB over both the 824–960 and 1710–2690 MHz bands, and the envelop correlation coefficient is less than about 0.03 over both bands. Port-decoupling of the two antennas is obtained because the excited surface currents on the system ground plane of the smartphone between the two antennas are decreased owing to the isolation ring strip attracting some of the same. In addition to good isolation obtained, the antenna efficiencies are better than about 40 and 50% over the lower and upper bands, respectively. Details of the decoupled WWAN/LTE antennas are described. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1470–1476, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27654

Journal ArticleDOI
TL;DR: In this article, a dual-band coaxial-fed 2 × 2 rectangular U-slot microstrip patch antenna array for multiple input multiple output (MIMO) applications, in 4G long term evolution (LTE) and WiMAX systems, is presented.
Abstract: In this article, a dual-band coaxial-fed 2 × 2 rectangular U-Slot microstrip patch antenna array for multiple input multiple output applications, in 4G long term evolution (LTE) and WiMAX systems, is presented. The targeted frequency bands are: (1) LTE Band-1 at 2.1 GHz, and (2) WiMAX at 3.5 GHz. Simple design procedure and optimization techniques are discussed to achieve the desired parameters. Antenna design and simulation is performed in Agilent ADS Momentum using RT/Duroid substrate (er = 2.2 and h = 3.175 mm). Substrate losses are also taken into account during design and simulation processes. The antenna is fabricated and characterized, and a comparison between the simulated and measured antenna is presented. The achieved impedance bandwidths/gains (determined by benchmark of voltage standing wave ratio ≤ 2) reach 2.4%/11.1 dBi and 2%/6.6 dBi for 2.1 and 3.5 GHz bands, respectively. The proposed antenna can be used as a template to form larger arrays. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2879–2883, 2013

Journal ArticleDOI
TL;DR: In this article, an isolation technique for two small-size triband wireless wide area network (WLAN) multiple-input multiple-output (MIMO) laptop computer antennas covering the 2.4/5.8 GHz bands is presented.
Abstract: An isolation technique for two small-size triband wireless wide area network (WLAN) multiple-input multiple-output (MIMO) laptop computer antennas covering the 2.4/5.2/5.8 GHz bands is presented. The proposed WLAN MIMO antennas have measured isolation of better than −21 dB in the 2.4 GHz band and −32 dB in the 5.2/5.8 GHz bands in this study. In addition to enhanced isolation achieved, good antenna efficiencies of better than about 70 and 90%, respectively, in the 2.4 GHz and 5.2/5.8 GHz bands are obtained for the two antennas. The WLAN MIMO antenna array having a planar structure of size 9 × 55 mm2 is to be mounted at the top edge of the supporting metal plate of the laptop display. The two antennas can be fabricated at low cost on a thin FR4 substrate and are of a simple structure comprising a driven strip and a shorted strip, which provides two wide operating bands to cover the 2.4 and 5.2/5.8 GHz bands. Between the two antennas, there is an isolation element formed by a protruded ground plane and a spiral open slot embedded therein. The isolation element leads to enhanced isolation between the antennas in the 2.4/5.2/5.8 GHz WLAN bands and good antenna efficiencies for the antennas as well. Details of the isolation technique for the WLAN MIMO antennas are described, and the obtained results are presented and discussed. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:382–387, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27279

Journal ArticleDOI
TL;DR: In this article, a triple band-notched ultra wideband (UWB) antenna is proposed based on an elliptical monopole antenna combined with a complementary split ring resonator (CSRR) structure and a spiral resonator.
Abstract: We propose a novel configuration of a triple band-notched ultra-wideband (UWB) antenna. The designed structure is based on an elliptical monopole antenna combined with a complementary split ring resonator (CSRR) structure and a spiral resonator. The spiral resonator can achieve the dual-band notched performance at WiMAX band and ITU 8 GHz by adjusting the length and width of a spiral line. Besides, the CSRR can obtain the notched band at WLAN 5 GHz by changing the radius of a ring slot. The designed antenna shows that a VSWR of less than 2 was satisfied with a resonant frequency in the range of 1.34–11.4 GHz with a 78.96%, except for triple notched bands. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:4–6, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27275

Journal ArticleDOI
TL;DR: In this article, the aperture-coupled regular and irregular pentagon-shaped dielectric resonator antennas (DRAs) are presented providing wideband and multiband performances.
Abstract: The aperture-coupled regular and irregular pentagon-shaped dielectric resonator antennas (DRAs) are presented providing wideband and multiband performances. The regular and irregular pentagon shape DRAs show wideband impedance matching (S11 = −10 dB) bandwidth of 42% (from 2.55 to 3.9 GHz) and 45.8% (from 2.57 to 4.1 GHz), respectively. Further, the irregular pentagon shape DRA also shows triple bands: 2.42–2.61 GHz (Band 1), 3.15–4.05 GHz (Band 2) and 5–5.65 GHz (Band 3) with a percentage matching bandwidths of 7.55, 23.77, and 12.2%, respectively. These DRAs offer acceptable directional radiation patterns for both wideband and multiband performances. Prototype of the regular pentagon shape DRA has been fabricated and experimentally verified for both the matching bandwidth and radiation performance. The simulated and measured results are in very good agreement. These DRAs can find applications in wireless communications devices such as base stations. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:395–400, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27338

Journal ArticleDOI
TL;DR: In this article, a slot-antenna-based frequency selective surface coupled with metal-oxide-metal diodes integrated into the structure is proposed for both infrared sensing and imaging as well as direct conversion of thermal energy.
Abstract: This article presents the design of a slot-antenna-based frequency selective surface coupled with metal-oxide-metal diodes integrated into the structure. This design takes advantage of a single self-aligned patterning step using shadow evaporation. The structure is optimized at 10.6 lm to have less than 2% reflection with 70% of the incident energy dissipated into the oxide layer. Initial experimental results conducted with e-beam lithography are presented. The fabricated structure is shown to produce a polarization sensitive unbiased DC current. This design will be useful for both infrared sensing and imaging as well as direct conversion of thermal energy. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:489-493, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27363

Journal ArticleDOI
TL;DR: In this paper, a refractive index optical fiber sensor based on surface plasmon resonance technology is demonstrated, in which half of the core is polished away and a thin-film layer of gold is deposited.
Abstract: A refractive index optical fiber sensor based on surface plasmon resonance technology is demonstrated. The sensing device is a multimode optical fiber in which half of the core is polished away and a thin-film layer of gold is deposited. We measure the spectrum-difference variations and the resonance wavelength shifts for different refractive index solutions. In terms of the experimental data, the characteristics including resolution, sensitivity, and signal-to-noise ratio for the sensor are obtained. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:574–576, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27397