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Showing papers in "Microwave and Optical Technology Letters in 2015"


Journal ArticleDOI
TL;DR: In this paper, a 10-antenna array operating in the 3.6 GHz band for multi-input multi-output (MIMO) operation in the smartphone is presented, where each antenna in the proposed array is a microstripline-fed open-slot antenna with same small dimensions of 3 × 8 mm2 (0.036λ × 0.096λ).
Abstract: A 10-antenna array operating in the 3.6-GHz band (3400–3800 MHz) for multi-input multi-output (MIMO) operation in the smartphone is presented. Each antenna in the proposed array is a microstripline-fed open-slot antenna with same small dimensions of 3 × 8 mm2 (0.036λ × 0.096λ, λ is the wavelength at 3.6 GHz). The proposed array consists of two symmetric five-antenna arrays disposed, respectively, along two long side edges of the system ground plane of the smartphone. The proposed array is expected to be placed in the narrow spacing between the display panel and the long side edges of the smartphone. Acceptable isolation (better than about 10 dB) and good envelop correlation coefficient (ECC) of less than 0.1 for any two antennas in the proposed array is obtained. The maximum channel capacity of the proposed array in a 10 × 10 MIMO system is calculated to reach about 47 bps/Hz at 20-dB signal-to-noise ratio, which is larger than four times that (11.5 bps/Hz) of the upper limit of an ideal 2 × 2 MIMO system with 100% antenna efficiency and zero ECC between antennas. Details of the proposed 10-antenna array are described, and the experimental results are presented and discussed. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1699–1704, 2015

131 citations


Journal ArticleDOI
TL;DR: In this paper, a microstrip patch antenna with complementary split ring resonator (CSRR) loaded ground plane is proposed for gain improvement, which has good radiation pattern and very good gain of 5.93 dBi at resonant frequency.
Abstract: In this article, microstrip patch antenna with complementary split ring resonator (CSRR) loaded ground plane is proposed for gain improvement. Gain was improved by introducing CSRR slots on the ground plane. The proposed antenna is designed, fabricated, and tested. Measured results are in good agreement with simulation results. The proposed antenna has a size of 40 × 46 × 1.6 mm3. The measured impedance bandwidth is 100 MHz (return loss <−10 dB) from 2.4 to 2.5 GHz, which covers instruments, scientific and measurement (ISM) band applications. Omnidirectional radiation pattern obtained in H-plane and bidirectional radiation pattern obtained in E-plane. Parametric study of CSRR was done to obtain best results. The proposed antenna is simple, has good radiation pattern, and very good gain of 5.93 dBi at resonant frequency. Size reduction of 10% was also achieved and bandwidth is slightly greater than unloaded antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:292–296, 2015

77 citations


Journal ArticleDOI
TL;DR: In this article, the authors used textile material as a substrate and designed an ultra wideband antenna for medical applications, which meets the requirements of wide working bandwidth and provides 13.08 GHz bandwidth with very small size, washable, and flexible materials.
Abstract: The concept of wearable products such as textile antenna are being developed which are capable of monitoring, alerting, and demanding attention whenever hospital emergency is needed, hence minimizing labor and resource. In the proposed work using textile material as a substrate, the ultra wideband antenna is designed especially for medical applications. Simulated and measured results here shows that the proposed antenna design meets the requirements of wide working bandwidth and provides 13.08 GHz bandwidth with very small size, washable (if using conductive thread for conductive parts) and flexible materials. Results in terms of bandwidth, radiation pattern, return loss as well as gain and efficiency are presented to validate the usefulness of the current proposed design. The work done here has many implications for future research and it could help patients with such flexible and comfortable medical monitoring techniques. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1553–1557, 2015

75 citations


Journal ArticleDOI
TL;DR: In this article, the authors present dielectric properties of air filled synthetic substrates fabricated in a single process using three-dimensional printing, and the permittivity and loss tangent of a given sized substrate can be changed by controlling the air infill volume fraction.
Abstract: This letter presents dielectric properties of air filled synthetic substrates fabricated in a single process using three-dimensional printing. The permittivity and loss tangent of a given sized substrate can be changed by controlling the air infill volume fraction. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2344–2346, 2015

66 citations


Journal ArticleDOI
TL;DR: In this article, a multiple-input multiple-output antenna array with two radiating elements having a wide bandwidth is reported, where spatial diversity has been introduced to achieve the diversity gain and the array was kept compact by introducing five parasitic decoupling elements on the bottom of the substrate; each having a length equal to k/2 at a specific frequency.
Abstract: A Multiple-input multiple-output antenna array with two radiating elements having a wide bandwidth is reported in this work. Spatial diversity has been introduced to achieve the diversity gain and the array was kept compact by introducing five parasitic decoupling ele- ments on the bottom of the substrate; each having a length equal to k/2 at a specific frequency. Each resonant element offers a resonant band- width of 1 GHz starting from 3 GHz to 8.5 GHz. Good agreement between the measured and simulated results shows that the antenna sys- tem performs very well over the frequency range 3 GHz to 8.5 GHz. In addition, an isolation of more than 15 dB is achieved with the help of the parasitic elements, while keeping an edge-to-edge and center-to- center separation of 4 mm and 19 mm, respectively. The proposed antenna measures 26 3 40.5 mm 2 , and it is suitable for handheld devi- ces, personal digital assistants, next generation home entertainment sys- tems, and robots. V C 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1677-1682, 2015; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.29162

63 citations


Journal ArticleDOI
TL;DR: An ultrathin quad-band polarization-insensitive wide-angle metamaterial absorber has been presented in this paper, which consists of a periodic array of concentric square and circular rings imprinted on grounded FR-4 dielectric substrate.
Abstract: In this article, an ultrathin quad-band polarization-insensitive wide-angle metamaterial absorber has been presented. The proposed structure consists of a periodic array of concentric square and circular rings imprinted on grounded FR-4 dielectric substrate. The simulated result shows that the structure has four discrete absorption peaks at 3.91, 5.16, 7.10, and 9.16 GHz with peak absorptivities of 99.35, 98.04, 99.85, and 99.78%, respectively. The proposed structure is symmetric in design providing nearly unity absorption for all polarization angles under normal incidence. It also shows high absorption (∼90%) for wide incident angles upto 45° for both transverse electric and transverse magnetic polarizations. By illustrating surface current distribution, the absorption mechanism of different parts of the proposed structure has been analyzed. Finally, the structure has been fabricated and the measured results are in good agreement with the simulated responses. The designed quad-band absorber is easy to manufacture and can be used in various potential applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:697–702, 2015

62 citations


Journal ArticleDOI
TL;DR: In this article, a novel semicircular shaped mono pole antenna has been investigated for super wideband (SWB) applications with high bandwidth dimension ratio (BDR), which is suitable for UWB outdoor propagation.
Abstract: In this article, a novel semicircular shaped mono pole antenna has been investigated for super wideband (SWB) applications with high bandwidth dimension ratio (BDR). The proposed antenna consists of semicircular shape patches and partial trapezoid ground plane. A tapered feed line is precisely connected to semicircle shaped patch, which provides extremely wide impedance bandwidth greater than ultra-wideband (UWB). The gap between the trapezoid ground plane and semicircular patch also plays a vital role to achieve wide impedance bandwidth. Studies of the antenna are performed using computer simulation tool HFSS. Prototype of the antenna is used for validation and verification for simulation results. Measurements to determine that the proposed printed antenna has an extremely wide impedance bandwidth (VSWR 2:1) from 1.30 to 20 GHz (175.58%) with a ratio bandwidth of 15.38:1 and BDR of 4261. 007 which is the highest among literature review. Furthermore, the proposed antenna also demonstrated a wide 14-dB bandwidth from 4.90 to 10.95 GHz, which is suitable for UWB outdoor propagation. The simple construction, much impedance bandwidth, average peak gain (4.18 dBi), and stable omnidirectional radiation pattern are a good deal sounder than the recently reported SWB antennas which make it appropriate for many wireless communication systems such as L band, WCDMA, ISM, Wi-Fi, LTE 2600, Bluetooth, WLAN, WiMAX, UWB, and MVDDS. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:445–452, 2015

60 citations


Journal ArticleDOI
TL;DR: In this article, a modified complementary split ring resonator metamaterial structures for enhancing isolation between the elements of densely packed microstrip phased array was proposed, which achieved a measured mutual coupling of −37.1 dB and return loss of −20.7 dB.
Abstract: This article reports on an efficient technique of using modified complementary split ring resonator metamaterial structures for enhancing isolation between the elements of densely packed microstrip phased array. A two element E-coupled microstrip phased array operating at 3.7 GHz with edge-to-edge element separation of 0.125 λo is realized. The proposed decoupling technique is analyzed by placing the metastructure in between the antennas on the patch layer as well as by etching it in the ground plane. Isolation enhancement of 14.6 dB is achieved when the metastructure is introduced on both top and bottom sides of the antenna array. The measured mutual coupling of −37.1 dB and return loss of −20.7 dB is demonstrated. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:759–763, 2015

50 citations


Journal ArticleDOI
TL;DR: In this article, a novel design for wideband radar cross section (RCS) reduction and gain enhancement microstrip antenna is proposed, where two 180° phase difference and modified artificial magnetic conductor cells are utilized to combine chessboard configuration superstrate (CCS).
Abstract: A novel design for wideband radar cross section (RCS) reduction and gain enhancement microstrip antenna is proposed. Two 180° phase difference and modified artificial magnetic conductor cells are utilized to combine chessboard configuration superstrate (CCS). The bottom side of CCS is etched slot and exploited to construct Fabry–Perot resonance cavity with ground plane of a microstrip antenna. The CCS can enable the primary antenna to obtain gain enhancement and RCS reduction simultaneously. Measured results show that the proposed antenna gain is enhanced by about 4.8 dB at 9.6 GHz and its 3 dB gain enhancement bandwidth is from 9.1 to 10.5 GHz. The half power beamwidth is suppressed from 101° to 12° in E-plane, while it is only 14° in H-plane, decreased by about 75° compared with the primary antenna. Meanwhile, the antenna RCS is dramatically reduced in a broad frequency range from 8.0 to 14.0 GHz, which contains the operation band of the proposed antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1738–1741, 2015

49 citations


Journal ArticleDOI
TL;DR: In this article, the authors designed a miniaturized carved planar metamaterial antennas with special configurations for wide band FR, microwave, and wireless communication systems, where the E-shaped slits and the split ring resonator as spiral inductors perform the roles of the series LH capacitors and shunt LH inductors, respectively, so that by optimizing these elements in their numbers and dimensions, the good operational performances of antennas can be achieved.
Abstract: New concepts to designing the miniaturized carved planar metamaterial antennas with special configurations for wide band FR, microwave, and wireless communication systems are presented. To realize the proposed antennas, composite right/left-handed (RH/LH) transmission lines (TLs) as a general TLs possessing both LH) and RH natures are implemented by the standard manufacturing techniques, so the E-shaped slits and the split ring resonator as spiral inductors perform the roles of the series LH capacitors (CL) and shunt LH inductors (LL), respectively, so that by optimizing these elements in their numbers and dimensions, the good operational performances of antennas can be achieved. The proposed antennas are constructed using two and three unit cells with E-shaped layouts having overall dimensions of 0.017λ0 × 0.006λ0 × 0.001λ0 and 0.028λ0 × 0.008λ0 × 0.001λ0, where λ0 is free space wavelength at the operating frequencies of 500 and 650 MHz, respectively. The antennas cover the frequency bandwidths of 500 MHz–1.35 GHz (850 MHz) and 650 MHz–1.85 GHz (1.2 GHz), which correspond to 91.9% and 96.0% fractional bandwidths, respectively. Besides the small dimensions and wide bandwidth characteristics, the measured gains and efficiencies are 5.3 dBi and 85% at 1 GHz for the first antenna, and 5.7 dBi and 90% at 1.4 GHz for the second antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2339–2344, 2015

43 citations


Journal ArticleDOI
TL;DR: In this article, a coplanar waveguide fed triple band antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WIMAX) applications.
Abstract: A coplanar waveguide fed triple band antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WIMAX) applications. The proposed antenna consists of rectangle monopole with modified ground plane and open complementary split ring resonator (OCSRR) loading. The overall size of the antenna is 30 × 40 × 0.8 mm3, which provides Omnidirectional pattern in all three bands. The prototype of antenna is designed, fabricated, and measured. The measured −10 dB impedance bandwidths are 300 MHz (2.40–2.70 GHz), 680 MHz (3.32–4.00 GHz), and 1040 MHz (4.76–5.8 GHz) with resonance frequency at 2.6 GHz,3.4GHz, and 5GHz, respectively, which is suitable for WLAN/WiMAX applications. Parametric study on OCSRR is discussed to validate the results. Simulated and measured results of the antenna are presented and discussed. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2413–2418, 2015

Journal ArticleDOI
TL;DR: In this article, a compact octagonal-shaped fractal ultrawideband (UWB) multiple-input-multiple-output (MIMO) antenna is presented and its characteristics are investigated.
Abstract: In this article, a compact octagonal-shaped fractal ultrawideband (UWB) multiple-input-multiple-output (MIMO) antenna is presented and its characteristics are investigated. The application of Koch fractal geometry at the edges of octagonal monopole provides desired miniaturization and wideband phenomena due to its self-similar and space filling properties. The two octagonal fractal antennas are placed orthogonal to each other and used to construct UWB MIMO antenna. An L-shaped stub is used in the ground plane of the geometry to provide an improvement in the isolation. The band rejection in wireless local area network band is achieved by etching a C-shaped slot from the monopole of the individual antenna. The compact dimension 40 × 25 mm2 of the antenna exhibits nearly omnidirectional radiation pattern, a low envelope correlation coefficient (<0.01), with good S-parameters over the entire UWB frequency range. The measured results show good agreement with the simulated one. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1919–1925, 2015

Journal ArticleDOI
TL;DR: In this paper, a coplanar waveguide-fed antenna with square spiral patch for multiband applications is presented, which consists of a square-spiral patch with two L-shape strips.
Abstract: A compact novel coplanar waveguide-fed antenna with square spiral-patch for multiband applications is presented. The antenna consists of a square-spiral patch with two L-shape strips. With subjoin square spiral the number of frequency resonance is increasing. Also by introducing two L-shaped strips in the inside of square spiral, much wider impedance bandwidth can be produced, especially at the higher bands. The operating frequencies of the proposed antenna are 2.62/3.40/4.42/5.92/8.32 GHz. Some key parameters affecting the antenna performance have been analyzed using computer simulations. To validate the simulation results, the prototypes of the proposed antenna are fabricated on an inexpensive FR-4 substrate and tested. Good radiation characteristics of the proposed antenna have been obtained. The simulated and measured results are in good agreement. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:111–115, 2015

Journal ArticleDOI
TL;DR: In this paper, a compact ultrawideband (UWB) antenna with three notch bands for polarization diversity applications is proposed, which is composed of two identical monopoles which can easily get UWB operation, and high isolation is obtained without using any extra decoupling structures.
Abstract: A compact ultrawideband (UWB) antenna with three notch bands for polarization diversity applications is proposed in this article. Composed of two identical monopoles which can easily get UWB operation, the antenna delivers polarization diversity operation by placing the two monopoles vertical to each other, and high isolation is obtained without using any extra decoupling structures. Three notch bands aiming to avoid interference to the UWB system are realized by two different types of resonators. Furthermore, a four-element UWB MIMO antenna is also presented. Both of them have great performance, making themselves good candidates for promising wireless polarization diversity communication systems. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:946–953, 2015

Journal ArticleDOI
TL;DR: In this article, a composite right/left-handed (CRLH) transmission line unit-cells implemented using slots and spiral inductors are etched directly on the dielectric substrate by standard manufacturing techniques.
Abstract: This letter presents a novel antenna that is based on composite right/left-handed (CRLH) transmission line unit-cells implemented using slots and spiral inductors that are etched directly on the dielectric substrate by standard manufacturing techniques. The antenna is designed to operate across 5.8–7.3 GHz, which corresponds to a fractional bandwidth of 23%. Measured results confirm the antenna exhibits a relatively wide bandwidth, high gain, and high radiation efficiency characteristics. The measured radiation gain, bandwidth, and efficiency of the antenna at 6.6 GHz are 4.8 dBi, 23%, and 78%, respectively. The fabricated antenna is highly compact and its physical size in terms of the free-space wavelength is 0.39λo × 0.13λo × 0.015λo.

Journal ArticleDOI
TL;DR: In this paper, an antenna with the characteristics of flexibility and transparency for use in laptop computers is presented, and the operating frequency band of the antenna is 5.18-5.32 GHz.
Abstract: This article presents an antenna with the characteristics of flexibility and transparency for use in laptop computers. The operating frequency band of the antenna is 5.18–5.32 GHz, in wireless local area network 802.11a service. The proposed antenna was fabricated on a polyamide substrate, and the conducting material for the antenna consisted of a multilayer film (IZTO/Ag/IZTO). In addition, we designed and measured two antennas with two electrodes (IZTO/Ag/IZTO and Ag) to compare and evaluate their performance and transparency. Moreover, we applied this antenna to laptop application and simulated and measured the performance dependence of the antenna by both the position and angle with the display plane (ground) of the laptop. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1038–1042, 2015

Journal ArticleDOI
TL;DR: In this paper, a dual open-loop antenna is proposed to provide enhanced bandwidth in near-field applications in the ultra-high frequency band, which is suitable for radio frequency identification reader applications.
Abstract: A compact dual open-loop antenna is proposed to provide enhanced bandwidth in near-field applications in the ultra-high frequency band. The antenna generates a strong and uniform magnetic field in a near-field zone of the smaller open-loop antenna. For increased bandwidth, two open loops with individual half-wavelength perimeters are etched on each side of an FR4 printed circuit board. The antenna was fabricated in a compact overall size (dimensions, 60 × 60 × 0.8 mm3) and achieves an interrogation zone of 50 × 50 mm2 with good impedance matching and uniform magnetic field distribution in a 888–932 MHz band. Performance tests indicate that the proposed antenna has a reading distance of up to 130 mm for near-field applications and is suitable for radio frequency identification reader applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2008–2012, 2015

Journal ArticleDOI
TL;DR: By incorporating a humidity-sensitive polyethylene oxide coating, a tapered optical MFC can work as a humidity sensor and demonstrated its sensing ability by monitoring spectral shifts in a wavelength domain this paper.
Abstract: Optical microfiber couplers (MFCs) with certain geometries are sensitive to local refractive changes. By incorporating a humidity-sensitive polyethylene oxide coating, a tapered optical MFC can work as a humidity sensor. We fabricated such a humidity sensor and demonstrated its sensing ability by monitoring spectral shifts in a wavelength domain. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:457–460, 2015

Journal ArticleDOI
TL;DR: In this paper, an ultrathin penta-band polarization-insensitive metamaterial absorber has been presented, which consists of an array of a closed ring embedded in a tetra-arrow resonator.
Abstract: In this article, an ultrathin penta-band polarization-insensitive metamaterial absorber has been presented, which consists of an array of a closed ring embedded in a tetra-arrow resonator. The proposed ultrathin (∼λ0/18 corresponding to the highest absorption frequency) structure exhibits five distinct absorption peaks at 3.4, 8.34, 9.46, 14.44, and 16.62 GHz with peak absorptivities of 98.6%, 96.6%, 90.1%, 97.8%, and 93.1%, respectively. Due to fourfold symmetry the structure provides nearly unity absorption for all polarization angles under normal incidence. The structure also exhibits high absorption peaks (∼80%) up to 45° incident angles for both TE and TM polarizations. Surface current and electric field distributions for different absorption frequencies have been analyzed to visualize the absorption mechanism of the structure. Finally, the structure has been fabricated and experimentally measured responses are in good agreement with the simulated ones. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2519–2524, 2015

Journal ArticleDOI
TL;DR: In this article, a compact microstrip-fed slot antenna with circular polarization characteristic for 5-6 GHz wireless local area network (WLAN) systems is presented, which consists of open-stub microstrip line in top layer and a circularly slotted ground plane with a pair of spur-shaped slits.
Abstract: In this article, a compact microstrip-fed slot antenna with circular polarization characteristic for 5–6 GHz wireless local area network (WLAN) systems is presented. The proposed antenna is fabricated on an FR4 substrate with dielectric constant of 4.4. The antenna configuration consists of open-stub microstrip-line in top layer and a circularly slotted ground plane with a pair of spur-shaped slits. The measured impedance bandwidth for l0 dB return loss is from 4.75 to 6.25 GHz with an axial ratio bandwidth of 5.15–5.85 GHz, covering 5.2/5.8GHz WLAN operating bands. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:756–759, 2015

Journal ArticleDOI
TL;DR: A linear open slot antenna with two open ends for the dual‐wideband LTE/WWAN operation in the 698–960 and 1710–2690 MHz bands is presented for the smartphone application and can provide two wide operating bands to cover the LTE/ WWAN operation.
Abstract: A linear open slot antenna with two open ends for the dual-wideband LTE/WWAN operation in the 698–960 and 1710–2690 MHz bands is presented for the smartphone application. The proposed antenna is referred to as a dual-opening slot (DOS) antenna and is especially suitable for the modern slim tablet device, such as a 5.5-inch smartphone. The DOS antenna has a slot length of 75 mm and a narrow slot width of 2 mm, and can be disposed with a short distance of 8 mm to the top or bottom edge of the smartphone. The DOS antenna will hence not overlap the display panel in the smartphone. This makes it promising and attractive for practical smartphone applications. As the DOS antenna has two open ends, two open slots [a first (longer) open slot and a second (shorter) open slot] can be created using a metal pad to short-circuit the DOS across its two parallel edges at a proper position. The first and second open slot antennas are then respectively excited by a first feed and a second feed. By further with the aid of wideband matching networks in the two feeds, the DOS antenna can provide two wide operating bands to cover the LTE/WWAN operation. Details of the DOS antenna are described in this study. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1269–1274, 2015

Journal ArticleDOI
TL;DR: In this article, a method has been proposed to increase the size of rectangular microstrip patch antenna (RMPA) for mm-wave and terahertz frequencies to increase fabrication tolerance.
Abstract: ABSRACT A method has been proposed to increase the size of rectangular microstrip patch antenna (RMPA) for mm-wave and terahertz frequencies to increase the fabrication tolerance. The method is experimentally tested on a RMPA designed at 56 GHz frequency where both the simulation and measured results are in good agreement. Moreover, the antenna's overall performance is also improved. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2585–2589, 2015

Journal ArticleDOI
TL;DR: In this article, a hexagonal-shaped fractal antenna with triangular slot for super wideband (SWB) application is presented, which has total size of 20 × 33.4 × 1.57 mm3.
Abstract: A hexagonal-shaped fractal antenna with triangular slot for super wideband (SWB) application is presented. The proposed antenna has total size of 20 × 33.4 × 1.57 mm3.The proposed antenna is designed of iterations of triangular slot on a hexagonal metallic patch with tapered microstrip line feed. A combination of semicircular and rectangular shaped partial ground plane is used to achieve a super wide bandwidth from 3 to 35 GHz with bandwidth ratio of 11.6:1. The antenna design, simulation and optimization are performed using IE3D Full Wave Electromagnetic Simulator. The proposed antenna is compact and has stable radiation pattern. The simulation and measured results are compared to demonstrate the performance of proposed antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1659–1662, 2015

Journal ArticleDOI
TL;DR: In this paper, the measured oscillillation frequency and output power as a function of varactortuning voltage were derived for a microwave IC tuned for 180 MHz in 14.89 to 15.06 GHz range by varying resonators' varactors.
Abstract: 59.8 andtand50.0022 at 10 GHz. Microwave IC is packaged in Alumin-ium test box. Upper cover height is considered to be at 11 mmand it is electromagnetically modeled and simulated. Carrierplate was made from Kovar and was plated with Gold. Metalli-zation process is Cr-Cu-Au with 17.5 lm accuracy. Measuredspectrum output is presented in Figure 5 when varactors arebiased at 8 V. Measured fundamental tone is at 14.98 GHz with6.87 dBm output power. Figure 6 shows the measured VCOoscillation frequency and output power as a function of varactortuning voltage. VCO can be tuned for 180 MHz in 14.89 to15.06 GHz range by varying resonators’ varactors from 0 to 22V. Measured output power remains in between 4.20 and 8.06dBm for the entire tuning range. The device draws 8.5 mA cur-rent at 3 V resulting into very low 25.5 mW dc power consump-tion. Measured phase noise is 260 dBc/Hz at 1 KHz offset and2145 dBc/Hz at 1 MHz offset from the carrier 14.98 GHz. Nor-malized phase noise figure of merit (PNFOM) for VCO can becalculated using [7],PNFOM ¼ LðÞDf 220log

Journal ArticleDOI
TL;DR: In this paper, a coplanner waveguide-fed broadband circularly polarized (CP) rectangular slot antenna is proposed, which is obtained using L-shaped feed line protruded from the signal line and rectangle-shaped parasitic element (PE).
Abstract: A new coplanner waveguide-fed broadband circularly polarized (CP) rectangular slot antenna is proposed. Circular polarization (CP) is obtained using L-shaped feed line protruded from the signal line and rectangle-shaped parasitic element (PE). The CP bandwidth can be significantly enhanced by placing a strip adjacent to the rectangle-shaped PE. By adjusting the length of the strip, the CP bandwidth is obtained as high as 48.28% (2.2–3.6 GHz) with axial ratio (AR) ≤ 3 dB. Impedance bandwidth of 63.97% (1.93–3.745 GHz) with VSWR ≤ 2 is achieved. The antenna has a small size of 60 × 50 mm2. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1788–1794, 2015

Journal ArticleDOI
TL;DR: In this article, a compact third iteration inner tapered tree-shaped fractal antenna for ultrawideband applications is presented, which has improved return loss performance and miniaturized size.
Abstract: In this article, a compact third iteration inner tapered tree-shaped fractal antenna for ultrawideband applications is presented. The bandwidth is enhanced by using CPW ground plane and increasing the number of iterations. An impedance bandwidth of 4.3–15.5 GHz (113%) is achieved. The proposed third iteration antenna has nearly omnidirectional patterns at its resonance frequencies with an acceptable value of gain. The experimental and simulation results are found to be in good agreement. The proposed antenna has improved return loss performance and miniaturized size. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:559–567, 2015

Journal ArticleDOI
TL;DR: In this article, a novel design of wideband ultrathin, low profile metamaterial microwave absorber has been presented, which is composed of a periodic array of microstrip bend-like structure printed on metal backed FR4 dielectric substrate.
Abstract: A novel design of wideband ultrathin, low profile metamaterial microwave absorber has been presented. The structure is composed of a periodic array of microstrip bend, like structure printed on metal backed FR4 dielectric substrate. The 10 dB absorption bandwidth from 8.60 to 12.35 GHz covering X-band has been observed in simulation for normal incidence. The FWHM bandwidth of 5.72 GHz has been observed ranging from 8.07 to 13.79 GHz. The proposed design is low profile (unit cell size 0.16 λ0) and is ultrathin (λ0/18 thick at center frequency of 10.47 GHz). The designed absorber is fabricated and experimentally verified for normal and oblique incidence angles. The performance of the proposed absorber at different angles of polarization has also been investigated. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2723–2728, 2015

Journal ArticleDOI
TL;DR: In this paper, a low-profile open-slot antenna capable of providing a triple-wideband LTE operation for the metal-framed smartphone is presented, which can fit in a narrow region between the metal frame and the display panel of the smartphone.
Abstract: A low-profile open-slot antenna capable of providing a triple-wideband LTE operation for the metal-framed smartphone is presented. The antenna has a low profile of 7 mm and can fit in a narrow region between the metal frame and the display panel of the metal-framed smartphone. The antenna comprises three branch slots sharing a same opening disposed at the top or bottom edge of the casing of the smartphone. Two branch slots are excited using a U-shape microstrip feedline with wideband matching circuits embedded therein while the third-branch slot is excited parasitically. With the proposed feeding arrangement, the antenna provides the triple-wideband LTE operation to cover the low band of 698–960 MHz, middle band of 1710–2690 MHz, and high band of 3400–3800 MHz. Details of the proposed open-slot antenna are presented and discussed. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2231–2238, 2015

Journal ArticleDOI
TL;DR: In this article, a detailed review of the fundamentals of electrically small antennas (ESAs) and its potential applications are presented. And constraints and challenges of ESAs are also presented in the article.
Abstract: The demand of compact antenna is ever increasing as the inception of wireless communication devices. In the age of wireless com- munication, requirement of miniaturized antennas is quite high. It is quite often that antenna dimensions are decided based on application- based requirement compared with practical antenna constraints. The trade-off in efficiency and other antenna parameters against to antenna size is always a debatable issue. The article presents detailed review of fundamentals of electrically small antennas (ESAs) and its potential applications. In addition, constraints and challenges of ESAs are also presented in the article. V C 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2386-2388, 2015; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.29335

Journal ArticleDOI
TL;DR: In this article, a microstrip line-fed antenna with five band-notched characteristics for UWB microwave applications is presented, which exhibits nearly omnidirectional radiation pattern and better surface current flow with a gain of 1.62 dBi.
Abstract: A compact microstrip line-fed antenna is presented with five band-notched characteristics for UWB microwave applications. Five band-notched characteristics have been achieved at the frequencies of 3.6, 5.2, 5.8, 7.5, and 8.3 GHz inseminating three C-shaped slots on the radiating circular patch and two C-shaped slots on the partial ground plane, which is validated experimentally by fabricating a printed prototype. This antenna exhibits nearly omnidirectional radiation pattern and better surface current flow with a gain of 1.62 dBi. This proposed antenna with VSWR < 2 and compact dimensions of 25 × 31 mm2 covers from 3.05 to 10.6 GHz, looking on forbidden 3.4–3.8 GHz WiMAX, 5–5.3 GHz WLAN, 5.6–6 WLAN, 7.2–7.65 GHz X-band satellite communication and 7.95–8.55 ITU 8-GHz band. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1470–1475, 2015