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Since the US Federal Communications Commission (FCC) released the unlicensed use of the ultra-wideband (3.1-10.6 GHz) spectrum for indoor and hand-held systems in Feb-2002[1]. Recently, the development of new UWB filters has increased via different methods and structures [2]??[5]. In [2] an initial UWB filter is presented by mounting a microstrip line in a lossy composite substrate to attenuate the...
Metamaterial as artificial material having exceptional electromagnetic properties recently comes up great attention. In particular, metamaterial with both negative permittivity and permeability have attracted widespread interest. Such composites can be constructed from an array of metallic pieces with special shapes. In this paper, heating characteristics are discussed for such metamaterial. Simulated...
In this paper, an exhaustive analysis of resonant type metamaterial transmission lines is carried out. Specifically, the effects of the dimensions and resonator characteristics on the frequency response are studied and interpreted to the light of the equivalent circuit model of the lines. This study is important for the application of these artificial lines to microwave circuit design, since important...
A novel dual-shorted monopole antenna suitable for UWB application, especially as an internal antenna for notebook or tablet PC has been proposed. The proposed antenna has a simple structure with a dual-shorted strip and is easy to implement at a low cost. Prototypes of the proposed antenna have been constructed and studied. A very uniform surface current distribution in the proposed antenna is occurred...
Multi focus imaging radar using two pair of inline Tx/Rx printed antennas has been proposed. Antipodal Fermi antennas have been employed both for Tx/Rx antennas. Basic characteristics of the proposed imaging radar including the effect of offset of Tx/Rx antennas have been discussed by experiments. Imaging of conducting rods located on styrofoam with 250mm range, and scissors and gun have been performed...
In the proposed method, the key point is the aperture and field coupling node. The former is based on small aperture coupling theory, the latter is based on transmission line theory, and electromagnetic topology theory (EMT) is the leader to combine them together. EMT has the ability to simulate the response of inner circuits of electrically large complex system. The application of this theory could...
This paper investigated the characteristics of a three-mode coupling in a dielectric slab waveguide with doubly periodic corrugation. Perturbation method was used to derive the coupled-mode equations and the reflection and transmission characteristics of the periodic waveguide of finite length were obtained. Results were obtained for the slab waveguide with doubly periodic corrugation when different...
In this paper, we propose a multi-band monopole antenna design which modifies the reduced-size planar monopole antenna [3], shown in Fig. 1(a), by inserting a new L-shaped slit and widening the width of the outer subpatch and gap distance between the outer subpatch and ground and let it excite a new 2.4 GHz band for ISM applications. The proposed design is described in detail in the following, and...
In this paper, another version of CBFM based on the dense scattering problems is combined with SVD and threshold technique to compute the scattering from the finite free-standing conformal FSS over a wide frequency under various incident conditions efficiently. The numerical examples show that the method applied in this paper can achieve significant savings in CPU time without the corruption of the...
In this paper, we have demonstrated the perpendicular dipole antenna with phase shift lines and shown the wideband characteristics of the antenna with phase shift lines in the same direction. The fractional bandwidth of the antenna with phase shift lines in the same direction is 89.5%. Radiation pattern of H-plane becomes almost omni-direction from 5 to 8 GHz.
In this paper, we present a miniaturized microstrip line monopole antenna(MLMA) using folded structure for a wearable antenna in Korean UHF band RFID system(operating frequency: 911.25MHz, bandwidth: 5.5MHz, wavelength lambda:329mm), which is highly capable of tracking and detecting due to its long read range. The suggested wearable antenna was designed as a low-profile antenna with a ground plane...
A new circularly-polarized (CP) dual-slot antenna fed by a single L-probe is proposed for dualband applications. The zonal slot and annular slot are perturbed symmetrically and asymmetrically to excite CP fields in the lower and upper bands, respectively. Ansoft HFSS was used to simulate the configuration. The return loss, axial ratio (AR) and radiation pattern of the dual-slot antenna are presented.
In this paper, a novel method to suppress harmonic component of PIFA is proposed. The spur-line is inserted between the feed and short line of PIFA and obstructs the feed line to suppress harmonic without induction of dual-band resonance. Additionally, partial ground is inserted the bottom side of radiator to improve the performance of suppression. The simulated and measured results show that the...
This paper extends the design theory of tunable matching network to consider frequency dependent load impedance. It illustrates the theoretical potential and the restriction of bandwidth enhancement for poorly matched monopole antenna by using tunable matching network. The technology of a prototype network using ferroelectric varactors based on barium-strontium-titanate is addressed. The bandwidth...
A dual-band unidirectional antenna has been developed. The dual-band antenna consists of a long dipole for the lower frequency band and two short dipoles for the higher frequency band. All dipoles are printed coplanar on a thin substrate. The printed dipole antenna is excited by a microstrip line. The higher-order mode in the higher frequency band has been suppressed, leading to a good unidirectional...
this paper a set of low permittivity DRAs are considered to investigate the capability of increasing impedance bandwidth. All proposed DRAs have the same dimensions and are fed by vertical strips. The effect of length, width, and thickness of the strip on the coupling value is examined. It is found that this approach can strongly feed DRAs with permittivities as low as 4. The structures are analyzed...
This work proposes a highly compact dual-band antenna design based on meander-line folded monopole for GSM/DCS handset applications. The first experimental prototype is design to cover GSM/DCS bands under the physical size constrain of 33 times 4 times 3 mm3. Good agreement between the numerical results and measured data is obtained. The acceptable measured gain performance of the first prototype...
This paper presents a novel and improved three-dimensional plane wave time domain (PWTD) algorithm. PWTD schemes constitute extensions of frequency domain fast multipole methods to the time domain, and permit the fast evaluation of transient wave fields generated by bandlimited sources. Previously, we demonstrated the equations pertinent to the analysis of electromagnetic scattering problems. Implementation...
As the design getting more complex, a design verification tools is required to ensure quality design. The extraction of L/C from layout is the first step for automatically layout vs. schematic (LVS) check. Computation geometry algorithms are applied to extract capacitors and inductors from layout of multi-layer circuits. The algorithm to generate overall schematic from extracted L/C is also presented...
In this paper, we consider a heterogeneous network, where objects of different kinds can ensure some amplify and forward function. In this case, objects can have different characteristics. We propose a thorough study of the energy consumption, taking into account efficiencies of the transmitter and relays. Given a quality of service, we minimize the global consumption and evaluate the impact of the...
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