Showing papers in "Microwave and Optical Technology Letters in 2007"
TL;DR: In this paper, a compact printed ultra-wideband slot antenna with superior multiple band-notched characteristics is presented, and multiple split ring resonators are printed inside the inner patch to achieve multiple notch frequency bands.
Abstract: A compact printed ultra-wideband slot antenna with superior multiple band-notched characteristics is presented. The size of the UWB slot antenna is minimized, and multiple split ring resonators are printed inside the inner patch to achieve multiple notch frequency bands. As a practical example, a UWB antenna (working from 2.4 to 10.1 GHz) etched with two sets of split ring resonators are fabricated and its VSWR and radiation patterns are measured. The measured results agree well with the simulation, and the two notch frequency bands are centered at 3.65 and 5.75 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 3056–3060, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22892
112 citations
TL;DR: In this paper, the series expansion of the Green's function is applied to the super-hyper singular kernel and closed-form expressions for their evaluations in the Cauchy principal-value sense are derived.
Abstract: The super-hyper singularity treatment is developed for solving three-dimensional (3D) electric field integral equations (EFIE). EFIE usually takes two forms: one of which includes a super-hyper singular kernel generated by the double gradient of the Green's function. So far, there is no way to evaluate these super-hyper singular integrals needed for constructing the pertinent matrix equation. We apply the series expansion of the Green's function to the super-hyper singular kernel and derive closed-form expressions for their evaluations in the Cauchy principal-value sense. The derivation is based on the constant current approximation over a flat triangle patch, but it can be extended easily to higher-order approximations of the current. The scheme can be used to accurately calculate the near and self interaction terms in the impedance matrix for the method of moments (MoM), Nystrom method or boundary element method (BEM). © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1383–1388, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22443
109 citations
TL;DR: In this article, an optimized design for the rectangular printed monopole antenna with a slitted groundplane is presented, where a slit in the ground plane is shown to reduce the lower-edge frequency and improve the bandwidth.
Abstract: An optimized design for the rectangular printed monopole antenna with a slitted groundplane is presented. A parametric study of antenna parameters, including the length and width of the ground plane, the length and width of the rectangular plate, and the gap between the patch and ground plane is presented. A slit in the ground plane is shown to reduce the lower-edge frequency and improve the bandwidth. A parametric study of the slit is given.© 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1585–1587, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22524
97 citations
TL;DR: In this article, a small (30mm x 35mm x 1.6mm) band-rejected U-slotted planar antenna on FR4 substrate having a relative permittivity of r=4.4 for Impulse Radio Ultra Wide Band (IR-UWB) systems is presented.
Abstract: This paper introduces the design of a small (30mm x 35mm x 1.6mm) band-rejected U-slotted planar antenna on FR4 substrate having a relative permittivity of r=4.4 for Impulse Radio Ultra Wide Band (IR-UWB) systems. The antenna is fed by a microstrip line and rejects the frequency band from 5.15GHz to 5.825GHz used by IEEE 802.11a and HIPERLAN/2. This antenna shows good characteristics for IR-UWB. The effects of variation on steps and U-Slot are discussed. The antenna is characterized both in the time and frequency domains by use of simulation and measurement.
90 citations
TL;DR: In this paper, effective electric permittivity and magnetic permeability for double negative metamaterial cells are extracted from 3D field simulation data using a homogeneous slab described with parameterized dispersive dispersive Drude and Lorentz models.
Abstract: Effective electric permittivity and magnetic permeability for metamaterial structures are extracted from 3D field simulation data. The equivalent representation of the metamaterial is a homogeneous slab described with parameterized dispersive Drude and Lorentz models. The parameters of dispersive models are obtained by optimization. Proposed approach is applied to the extraction of effective material parameters for double negative metamaterial cells. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 285–288, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22105
87 citations
TL;DR: In this paper, a novel UHF band RFID tag antenna, which can be effectively mounted on metallic objects, is presented using the inductively coupled feeding technique, the proposed antenna consists of two symmetric shorted radiating elements and feeding loop.
Abstract: A novel UHF band RFID tag antenna, which can be effectively mounted on metallic objects, is presented. Using the inductively coupled feeding technique, the proposed antenna consists of two symmetric shorted radiating elements and feeding loop. The feeding loop is excited so that the currents on the radiating elements are out of phase with the equal amplitude. The proposed tag antenna gives smaller variation of the antenna performance than that of conventional tag antennas when the tag is mounted on the various sizes of the metallic objects. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 414–416, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22159
84 citations
TL;DR: In this article, a new ultrawideband antenna is presented, and the fractal structure is used to obtain such a wideband feature, the parameters and the characteristics of the antenna are given.
Abstract: A new ultrawideband antenna is presented in this letter, and the fractal structure is used to obtain such a wideband feature. The parameters and the characteristics of the antenna are given. The simulated and the measured results show that a bandwidth larger than 6:1 is achieved. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 173–176, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22078
71 citations
TL;DR: In this paper, a novel internal coupling element-based antenna structure for quad-band mobile terminals is presented, which consists of two non-resonant coupling elements, a multi-resonsant matching circuitry, and the chassis of the mobile terminal.
Abstract: A novel internal coupling element-based antenna structure for quad-band mobile terminals is presented. The antenna structure comprises of two nonresonant coupling elements, a multi-resonant matching circuitry, and the chassis of the mobile terminal. The coupling elements occupy an extremely low volume of only 0.7 cm3, and they have a very low profile of only 4 mm. Despite of the low volume and low profile of the antenna structure, it can fulfill the bandwidth requirements of the GSM850/900 and GSM1800/PCS1900 systems with sufficiently high efficiency, thus making it a promising antenna candidate for future mobile terminals. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1277–1282, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22463
68 citations
TL;DR: In this paper, small N-section resonators in the form of slots on the ground plane were proposed to reduce the mutual coupling and get high isolation between two internal dual-band antennas, and optimized small size resonators for high isolation, antenna radiation efficiency, and high effective diversity were analyzed.
Abstract: The high isolated dual-band inverted-F diversity systems for portable devices, operating in 2.4 GHz band (2400–2484 MHz) and 5.2 GHz band (5150–5350 MHz), are presented. To reduce the mutual coupling and get high isolation between two internal dual-band antennas, we proposed the small N-section resonators in the form of slots on the ground plane. The optimized small size resonators for high isolation, antenna radiation efficiency, and high effective diversity are analyzed. Because of their small size, N-section resonators can be widely used in small diversity systems that require high isolation between antennas. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 731–734, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22238
67 citations
TL;DR: In this article, an anisotropic metamaterial layer is designed as conformal to the surface of the scatterer by employing the concept of coordinate transformation, which renders an object perceived as having a different shape regardless of the location of the observer.
Abstract: We introduce a new technique (in the context of time-harmonic electromagnetic scattering), which renders an object (or scatterer) to be perceived as if it has a different shape, irrespective of the location of the observer. This is achieved through the usage of an anisotropic metamaterial layer, which is designed as conformal to the surface of the scatterer by employing the concept of coordinate transformation. We report some numerical results for finite element simulations of two-dimensional anisotropic metamaterial coatings. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2386–2392, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22784
64 citations
TL;DR: An integral equation‐based overlapped domain decomposition method (IE‐ODDM) is presented for the analysis of three‐dimensional electromagnetic scattering problems and the iterative sequence among the subdomains is more flexible, which means that asynchronous iteration and even parallel computing are doable.
Abstract: An integral equation-based overlapped domain decomposition method (IE-ODDM) is presented for the analysis of three-dimensional (3D) electromagnetic scattering problems. Compared with the forward and backward buffer region iterative method proposed by Brennan et al., the convergence of the IE-ODDM is faster due to the edge-effect of the current in each subdomain being effectively depressed. Moreover, the iterative sequence among the subdomains of IE-ODDM is more flexible, which means that asynchronous iteration and even parallel computing are doable. Simulated RCS results of several convex and concave 3D conducting objects verify the speedup and validity of this method. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 265–274, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22110
TL;DR: In this paper, a printed circular patch antenna with a band-notched characteristic is presented, where a pie-shaped slot on the circular radiating patch is used to create a frequency band notch.
Abstract: A novel and simple design of a printed circular patch antenna for ultra-wideband application with a band-notched characteristic is presented. By cutting a pie-shaped slot on the circular radiating patch, a frequency band notch will be created. The cutting pie depth contributes to the notch center frequency and notch bandwidth while the pie flare angle contributes to the notch bandwidth. It is easy to design a specific notch band range by adjusting the cutting pie size. The position of cutting pie is also investigated. Details of the proposed designs and experimental results of the constructed prototypes are presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 316–320, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22113
TL;DR: In this paper, an internal meandered loop antenna for application in a mobile phone for Global System for Mobile Communication/Digital Communication System/Personal Communication System (GSM/DCS/PCS) multiband operation is presented.
Abstract: A novel internal meandered loop antenna for application in a mobile phone for Global System for Mobile Communication/Digital Communication System/Personal Communication System (GSM/DCS/PCS) multiband operation is presented. Along the symmetric metal-strip loop structure of the antenna, there are meandered sections for adjusting the antenna's resonant frequencies and widened sections for improving the impedance matching. The antenna's first and second resonant modes (half- and one-wavelength modes) excited at about 900 and 1800 MHz for GSM/DCS operation. With the meandered sections in the loop structure, the antenna's third resonant mode (1.5-wavelength mode) can be adjusted to be close to the second resonant mode at 1800 MHz to achieve a wider upper band for DCS/PCS operation. In addition, the central region of the proposed loop antenna is unoccupied, which can be used to accommodate possible nearby electronic components, such as the lens of a digital camera. Furthermore, effects of the user's hand holding the mobile phone with the proposed loop antenna are analyzed in this study. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 759–765, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22271
TL;DR: In this article, two band-stop techniques for UWB antenna design are suggested, which have wide bandwidth enough to cover UWB services along with the bandstop characteristic for 5 GHz WLAN band.
Abstract: Two band-stop techniques for UWB antenna design are suggested in this article. The proposed antennas have wide bandwidth enough to cover UWB services along with the band-stop characteristic for 5 GHz WLAN band. By inserting an U-shaped slot or attaching an inverted Y-shaped short-circuited stub, the band-stop characteristic is obtained. Prototypes of the proposed antennas are implemented and the parametric studies of the two band-stop techniques are performed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49:1058–1062, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22363
TL;DR: In this paper, the authors presented the design, simulation, fabrication, and characterization of a transmission delay line-based RFID tag for low-end commercial applications that has a large market.
Abstract: This paper presents the design, simulation, fabrication, and characterization of a transmission delay line-based RFID tag. The ID generating circuit is designed based on the transmission delay line concept. A compact, inset-fed triangular patch antenna resonant at 915 MHz frequency is developed for integration with the tag application. The layout of the tag has been realized using conventional photolithography. Tags with a 5- and 10-ns delay ID generation circuits have been tested using input signals of 10-ns width. An OOK (On-Off Keying) modulation technique is employed for characterization of the tag. The received output consists of delayed signal from the tag added to the direct signal from the transmitter. Transmission delay line-based RFID technology can be exploited for low-end commercial applications that has a large market. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1900–1904, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22599
TL;DR: In this paper, approximate equations to calculate the resonant length of various compact rectangular microstrip antennas like, C-shaped, H-shaped and rectangular ring microstrip antenna, are proposed.
Abstract: The approximate equations to calculate the resonant length of various compact rectangular microstrip antennas like, C-shaped, H-shaped, and rectangular ring microstrip antenna, are proposed. The error in the calculated resonance frequency is <5%. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 498–501, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22161
TL;DR: In this paper, a coplanar waveguide fed monopole ultra-wideband antenna with a frequency-notch function is proposed and measured return loss, radiation patterns, and gains are presented.
Abstract: A compact coplanar waveguide fed monopole ultra-wideband antenna having a frequency-notch function is proposed. The notched frequency band can be achieved by including the two L-shape striplines in the bottom of the substrate. The designed antenna has a notch band of 5.10–6.25 GHz while 10 dB return loss is ranged from 3.04 to 12.0 GHz. The measured return loss, radiation patterns, and gains are presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2747–2750, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22852
TL;DR: In this paper, a reconfigurable coplanar waveguide (CPW)-fed square slot antenna with switchable polarization is presented, with two T-shaped metal strips connected to ground plane using pin-diodes.
Abstract: A novel reconfigurable coplanar waveguide (CPW)-fed square slot antenna with switchable polarization is presented. The proposed antenna is fed by a CPW, with two T-shaped metal strips connected to ground plane using pin-diodes. Switching between right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) is achieved by turning the pin-diodes on or off. The designed antenna is implemented and measured. It shows that the proposed antenna has broad CP bandwidth in both RHCP and LHCP states. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1233–1236, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22476
TL;DR: In this paper, a planar slot-array antenna fed by a new guiding structure was proposed, which forces a quasi-TEM mode within an oversized rectangular waveguide to propagate invariant linear phasefronts along the axial direction.
Abstract: We propose a novel planar slot-array antenna fed by a new guiding structure which forces a quasi-TEM mode within an oversized rectangular waveguide. To achieve a quasi-TEM mode throughout the waveguide a hard surface is placed on the bottom surface of the waveguide while the radiating slots are at the upper face. The waveguide is able to propagate invariant linear phase-fronts along the axial direction which makes it attractive for steerable array antennas. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1875–1877, 2007; Published online in Wiley Inter-Science (www.interscience.wiley.com). DOI 10.1002/mop.22586
TL;DR: In this paper, a printed inverted "F" antenna (PIFA) was used to design a miniaturized triband antenna, which has been used as an element in various arrays of MIMO applications.
Abstract: Multiband antennas are vital in meeting the modern tele- communication demands of mobile terminals. Using the spatial properties of multipath channels, multiple-input multiple-output (MIMO) communica- tion systems employ antenna arrays to increase their communication capac- ity. This article presents a novel printed inverted "F" antenna (PIFA), which has been used to design a miniaturized triband antenna. In turn, the triband antenna has been used as an element in various arrays of MIMO applications. Specifically, the antenna element has been constructed and applied, in arrays of two and four, in a laptop PCMCIA wireless LAN card. The size of the four element MIMO antenna array is 50 mm 13 mm 8 mm, which translates to 0.4 0.1 0.06 at 2.45 GHz. The input im- pedance of the single element antenna has been measured at UCLA. The antenna has a return loss lower than 10 dB within the 2.4 -2.5 GHz, 5.15-5.35 GHz, and 5.7-5.85 GHz bands. The measured scattering matri- ces of two and four element arrays have been used to calculate the total active reflection coefficient (TARC). TARC has been calculated for different combinations of excitation signals applied at each port. Each excitation signal has a unity magnitude and a random phase, thus leading to innumer- able signal combinations. Our results reveal that "off" diagonal elements of the scattering matrix (couplings between elements) are as important as di- agonal elements in calculating the TARC and the radiation efficiency of arrays. Furthermore, increasing the number of elements in a MIMO system with a limited volume will increase the channel capacity but lower the radiation efficiency. The experimental and simulation results have been in agreement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 724 -731, 2007; Published online in Wiley Inter- Science (www.interscience.wiley.com). DOI 10.1002/mop.22239
TL;DR: In this article, the authors measured the shift in the resonant frequency caused by the insertion of the sample inside the cavity, which can be related to the real part of the complex permittivity, ϵ′, and the change in the inverse of the quality factor of the cavity.
Abstract: The design of a cavity resonator implies to solve the Maxwell equations inside that cavity, respecting the boundary conditions. As a consequence, the resonance frequencies appear as conditions in the solutions of the differential equation involved. The measurement of the complex permittivity, ϵ* = ϵ′-iϵ″, can be made using the small perturbation theory. In this method, the resonance frequency and the quality factor of the cavity, with and without a sample, can be used to calculate the complex dielectric permittivity of the material. We measure the shift in the resonant frequency of the cavity, Δf, caused by the insertion of the sample inside the cavity, which can be related to the real part of the complex permittivity, ϵ′, and the change in the inverse of the quality factor of the cavity, Δ(1/Q), which can be related with the imaginary part, ϵ″. This is valid for very small perturbations of the electric field inside the cavity by the insertion of a sample. For materials with high losses, the perturbation can be very high, making impracticable the use of this technique. The solution is to use high volume cavities. In this work we report the design and the performance tests of a cavity to be used with high loss materials. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1687–1690, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22506
TL;DR: In this article, a two-cascaded semiconductor optical amplifiers (SOAs) in a counter-propagating topology are used to obtain an all-optical logic OR gate with an extinction ratio higher than 7 dB.
Abstract: A novel all-optical logic OR gate based on cross-gain modulation (XGM) using a two-cascaded semiconductor optical amplifiers (SOAs) in a counterpropagating topology is presented. The attractive issue of the proposed method is that the logic OR gate can be obtained at a probe wavelength by taking advantage of the positive gain variation of one of the two used SOAs in the counterpropagating configuration. This reported feasibility study shows the all-optical logic OR gate can be easily achieved with an extinction ratio higher than 7 dB.© 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1568–1570, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22560
TL;DR: In this article, a particular antenna structure, working as a transmit-array structure (reception/transmission lens), is presented, which consists of a patch array in the reception part, a phase delay for each patch, and another patch array for the transmission part.
Abstract: The aim of the paper below is to present a particular antenna structure, working as a transmit-array structure (reception/transmission lens). Because of its working function, the structure consists of a patch array in the reception part, a phase delay for each patch and another patch array in the transmission part. The idea in using this lens is to place it in front of a particular antenna to modify the radiation pattern of the feeding antenna. The architecture which is being applied implies the use of patches with probe feeding. To avoid undesired coupling between the reception and the transmission arrays, ground planes (that isolate the reception array, the phase delay line, and the transmission array) are placed. In this article, the phase delay part, the radiation part, and the whole structure are analyzed, designed, simulated, and prototyped. Finally, measurements of these prototypes are shown. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 3020–3026, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22950
TL;DR: In this paper, an internal shorted monopole antenna suitable to be embedded within the watch-type wireless communication device is presented, which provides a wide bandwidth for Bluetooth operation in the 2.4 GHz band (2400-2484 MHz).
Abstract: An internal shorted monopole antenna suitable to be embedded within the watch-type wireless communication device is presented. The antenna generally has a planar configuration and is mounted conformal along the side surfaces of the wireless device to operate as an internal or concealed antenna. The antenna also shows a low profile of 4 mm only, yet providing a wide bandwidth for Bluetooth operation in the 2.4 GHz band (2400–2484 MHz). In addition, the antenna is designed to be short-circuited to an upper ground plane mounted above the main system ground plane of the wireless device. With the proposed arrangement, reduced coupling between the antenna and the nearby lossy medium can be achieved. Hence, when the wireless device with the proposed antenna is worn around the user's wrist or forearm, which functions as a lossy medium, the antenna's radiation efficiency can still reach about 50% over the operating band. Details of the proposed antenna and the promising watch-type wireless communication device are presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 942–946, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22322
TL;DR: In this article, the theoretical and simulation investigations of an E-shaped patch antenna applicable in modern mobile communications are presented, which shows marked improvement in the bandwidth when compared with rectangular patch antenna with acceptable radiation pattern.
Abstract: This paper presents the theoretical and simulation investigations of an E-shaped patch antenna applicable in modern mobile communications. It shows marked improvement in the bandwidth when compared with rectangular patch antenna with acceptable radiation pattern. Further, the bandwidth is optimized with respect to notch length, width, and position. Typically, the antenna shows an enhanced impedance bandwidth of 32.5%. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 4–7, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22024
TL;DR: In this article, a directive broadband printed Yagi-like antenna design is presented for the 2.45 GHz WLAN band, at which some designs have been carried out and some selected prototypes have then been fabricated onto a low-cost printed circuit board dielectric substrate.
Abstract: A directive broadband printed Yagi-like antenna design is presented. We have focused on the 2.45 GHz WLAN band, at which some designs have been carried out. For the design and the modelling processes, we made use of FDTD based in-house developed algorithms. Some selected prototypes have then been fabricated onto a low-cost printed circuit board dielectric substrate and tested successfully. Bandwidths higher than 10% and moderate to high (>7 dBi) gains can be obtained this way. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2174–2178, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22655
TL;DR: In this article, a ring-shaped frequency selective surface (FSS) superstrate is designed to enhance the directivity of a circularly polarized patch antenna by reducing the sidelobe levels.
Abstract: In this letter, a ring-shaped frequency selective surface (FSS) superstrate is designed to enhance the directivity of a circularly polarized patch antenna by reducing the sidelobe levels. Based on the unit cell simulation, several important parameters that characterize the ring-shaped FSS superstrate are investigated, and the design procedure of the FSS superstrate is described. The FSS antenna composite is fabricated, and the maximum directivity is 18.98 dBi, while the sidelobe level is −18 dB. Furthermore, the antenna composite maintains its circular polarization characteristic quite well. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 199–201, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22084
TL;DR: In this article, a printed folded slot antenna suitable for GSM/DCS/PCS/UMTS multiband operation in the mobile phone is presented, which has a planar configuration and is easy to fabricate by printing on the system circuit board of mobile phone.
Abstract: A novel printed folded slot antenna suitable for GSM/DCS/PCS/UMTS multiband operation in the mobile phone is presented. The proposed slot antenna has a planar configuration and is easy to fabricate by printing on the system circuit board of the mobile phone. The slot antenna has a length of 106 mm and is folded into a compact structure with its two slot ends facing toward each other. This configuration allows the antenna to occupy a small area of 21 × 45 mm2 centered on the top portion of the system ground plane. By feeding the slot antenna using a 50 Ω microstrip line printed along the centerline of the system ground plane, two wide bands (the half- and one-wavelength modes) of the antenna can be generated, with the lower band covering GSM operation and the upper band covering DSC/PCS/UMTS operation. In addition, small excited surface currents in the system ground plane are observed, and the antenna's two operating bands are in general not sensitive to the ground-plane length variations. These features are attractive for practical applications and different from those of the conventional internal mobile phone antennas. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1833–1837, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22602
TL;DR: In this paper, the authors applied the method of Foldy-Lax multiple scattering equations to multiple vias in ball grid arrays and the interior layers of printed circuit boards and verified the results with Ansoft's HFSS with very little difference between the FoldyLax approach and the HFSS results.
Abstract: The authors applied the method of Foldy-Lax multiple scattering equations to multiple vias in ball grid arrays and the interior layers of printed circuit boards. The method gives the scattering param- eters of the array. The results are verified with Ansoft's HFSS with very little difference between the Foldy-Lax approach and the HFSS results.
TL;DR: In this paper, a quasi-planar chiral resonator is proposed for negative refractive index metamaterials, which can be used for photo-etching of inclusions.
Abstract: This work proposes a quasi-planar chiral resonator suitable for the design of negative refractive index metamaterials. It is presented as an analytical model to determine the metamaterial polarizabilities, which is also the basis of a further study of the viability of negative refraction in chiral and racemic arrangements of inclusions made up with the proposed quasi-planar chiral resonator. The present analysis is expected to pave the way for the design and building of feasible negative refractive index metamaterials whose inclusions can be manufactured by means of standard photo-etching techniques. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2606–2609, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22736