Resonant Paths Research Articles

Small UWB Planar Monopole Antenna With Added GPS/GSM/WLAN Bands

A small-size microstrip-fed multi-band planar monopole antenna is presented. The base of the proposed antenna is a diamond-shaped-patch (DSP) that covers the ultrawideband (UWB) frequency range. To create a multi-band antenna, several narrow strips, acting as resonance paths, can be integrated with the DSP antenna. It is shown that by removing the centre part of the DSP antenna, without distorting the UWB behavior, quarter-wavelength strips can be added to the notched region. This will not affect the dimension of the base antenna. The designed quad-band antenna has a substrate size of 16 × 22 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and covers the frequency bands 1.3, 1.8, 2.4 and 3.1-10.6 GHz which includes GPS, GSM, WLAN and UWB. Dual-, triple- and quad-band antennas are simulated and good results are obtained. The antennas have omnidirectional and stable radiation patterns across all the relevant bands. Moreover, relatively consistent group delays across the UWB frequencies are noticed for the base, dual- and triple-band antennas, and slightly distorted for the quad-band antenna. A prototype of the quad-band antenna is fabricated and measured results are compared with simulated results.

UWB 하반 대역 WVAN Gbps 데이터 전송률 트랜시버용 소형 광대역 안테나의 설계

본 논문에서는 UWB 하반 대역의 WVAN Gbps 데이터 전송률 트랜시버용 소형 안테나를 설계하였다. 제안된 안테나는 광대역 특성을 얻기 위하여 부분 접지면 상에서 사각형 모노폴에 링형 스터브와 개방 스터브를 부착하여 다수의 공진 전류 경로를 가짐으로써 -10 dB 이하 반사 손실 영역을 넓혔다. 설계된 안테나는 전자기모의시험을 거쳐 제작되었고, UWB 하반 대역인 3.197~4.732 GHz에서 -10 dB 이하의 반사 손실과 5 dBi 이상의 안테나 이득과 80 % 이상의 효율 특성을 보였다. 따라서 제작된 안테나는 소형화는 물론 우수한 성능의 무선 통신 트랜시버용으로 적합한 것으로 판단된다. In this paper, a compact antenna is designed for the UWB lower half-band WVAN Gbps data-rate transceiver. The proposed antenna broadens the bandwidth less than -10 dB by placing the ring stubs and an open stub on the rectangular monopole above the partial ground and creating multiple resonant current paths. The designed antenna goes through the electromagnetic simulation and is fabricated and the implemented antenna has the characteristics of the return loss lower than -10 dB, the antenna gain greater than 5 dBi, and the efficiency over 80 % in the UWB lower half-band ranging from 3.197 GHz to 4.732 GHz. Therefore, it is thought that the proposed antenna is suitable for the size-reduced and excellently performing wireless communication transceiver.

Numerical continuation of bound and resonant states of the two-channel Schrödinger equation

Resonant solutions of the quantum Schr\odinger equation occur at complex energies where the $S$ matrix becomes singular. Knowledge of such resonances is important in the study of the underlying physical system. Often the Schr\odinger equation depends on some parameter and one is interested in following the path of the resonances in the complex energy plane as the parameter changes. This is particularly true in coupled-channel systems where the resonant behavior is highly influenced by the strength of the channel coupling, the energy separation of the channels, and other factors. In previous work it was shown that numerical continuation, a technique familiar in the study of dynamical systems, can be brought to bear on the problem of following the resonance path in one-dimensional problems [J. Broeckhove, P. Klosiewicz, and W. Vanroose, J. Comput. Appl. Math. 234, 1238 (2010).] and multichannel problems without energy separation between the channels [P. K\l{}osiewicz, J. Broeckhove, and W. Vanroose, Commun. Comput. Phys. 11, 435 (2012).]. A regularization can be defined that eliminates coalescing poles and zeros that appear in the $S$ matrix at the origin due to symmetries. Following the zeros of this regularized function then traces the resonance path. In this work we show that this approach can be extended to channels with energy separation, albeit limited to two channels. The issue here is that the energy separation introduces branch cuts in the complex energy domain that need to be eliminated with a so-called uniformization. We demonstrate that the resulting approach is suitable for investigating resonances in two-channel systems and provide an extensive example.

Competition of Resonant and Nonresonant Paths in Resonance-Enhanced Two-Photon Single Ionization of He by an Ultrashort Extreme-Ultraviolet Pulse

We theoretically study the pulse-width dependence of the photoelectron angular distribution (PAD) from the resonance-enhanced two-photon single ionization of He by femtosecond (≲20 fs) extreme-ultraviolet pulses, based on the time-dependent perturbation theory and simulations with the full time-dependent Schrödinger equation. In particular, we focus on the competition between resonant and nonresonant ionization paths, which leads to the relative phase δ between the S and D wave packets distinct from the corresponding scattering phase shift difference. When the spectrally broadened pulse is resonant with an excited level, the competition varies with pulse width, and, therefore, δ and the PAD also change with it. On the other hand, when the Rydberg manifold is excited, δ and the PAD do not much vary with the pulse width, except for the very short-pulse regime.

Compact, printed, dual‐feed, shorted monopole antenna for concurrent 2.4‐ and 5‐GHz WLAN operation

AbstractA compact and printed monopole antenna having two feeding ports to operate in the 2.4‐ and 5‐GHz bands respectively for concurrent dual‐band operation is proposed.The monopole and the ground plane thereof were formed on a single‐layered FR4 substrate of thickness 1 mm and with the dimensions 30 mm × 37 mm. The main radiating element is of a bent, two‐branched strip monopole, placed 2 mm away from the antenna ground. Each branch provides one resonant path such that two operating bands are generated. It was found that by feeding the monopole on the opposite sides with two shorting portions set therein between, the single antenna can be excited by the 2.4‐ and 5‐GHz radio signals at the same time with the port decoupling below −20 dB. The antenna is simple in structure and has constant strip width. Details of the design prototypes are discussed in the article. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:188–193, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26502

Compact and printed, standalone wireless wide area network antenna incorporating a conductive wire at low cost

AbstractA compact and printed multiband antenna incorporating a conductive wire for wireless wide area network (WWAN) operation is presented. The antenna was formed on a low‐cost, single‐layered dielectric substrate of thickness 1 mm with the dimensions 10 × 55 mm2. The antenna is a couple‐fed short‐circuited monopole in the shape of T, which consists of two resonant paths for two wide operating bands. Unlike the conventional WWAN antennas utilizing a large system ground plane as the antenna ground to excite the antenna, the proposed antenna has a very small ground portion with comparable size to the radiating monopole and yet can also cover the GSM850/900 and GSM1800/1900/UMTS bands by incorporating a simply wire. The design is especially suited to some e‐book reader applications, in which the supporting metal frame for the E‐ink display is not required. In this case, the proposed antenna with long, narrow structure can be placed in the space between the casing and the display with the wire routed within the device. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:109–113, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26452

Plasmon induced transparency in a dielectric waveguide

A classical effect of electromagnetically induced transparency (EIT) is demonstrated in a dielectric slab waveguide at visible frequencies. Two nano-sized elliptical silver particles are placed inside the waveguide core layer, and their localized plasmonic resonances are utilized to obtain bright and dark states. The destructive interference between the two resonance paths leads to an EIT-like transmission spectrum of the waveguide. The contrast between the transmission peak and dip can be further enhanced by incorporating the Fabry-Perot resonance effect. The influence of Joule loss on the EIT performance is also investigated.

Design of a Compact Dual-Band Bandpass Filter Using Opposite Hook-Shaped Resonator

In this letter, a compact dual-band bandpass filter is presented for wireless area networks (WLAN) operations. The filter, which is only 0.04 λ0 × 0.09λ0 in overall dimensions, is composed of two symmetric parts. In each part, two opposite hook-shaped strips with different resonant paths are used to achieve the dual-band operation at 2.4 and 5.8 GHz, with 19.54% and 15.12% fractional bandwidth, respectively. The central frequencies of the two passbands can be controlled independently by adjusting dimensions of the hooks. To verify the proposed idea, a prototype is implemented, and the measurement results agree well with the full-wave electromagnetic simulated responses.

FANO-TYPE SPIN-FLIP MESOSCOPIC TRANSPORT THROUGH AN AHARONOV–BOHM INTERFEROMETER RESPONDED BY AC MAGNETIC FIELDS

We have investigated the mesoscopic transport properties of an Aharonov–Bohm (AB) interferometer composed of a direct tunneling path and a resonant tunneling path incorporating a quantum dot (QD). The QD is perturbed by a rotating magnetic field (RMF) and an oscillating magnetic field (OMF). The nonresonant tunneling (NRT) path takes significant role in the spin and charge currents, and the Fano profiles display in the currents due to the modification of NRT strength. The spin current exhibits completely different behaviors as the source–drain bias eV = 0 and eV≠0. The spin current is symmetric versus gate voltage when the source–drain bias eV = 0; however, it becomes asymmetric Fano-line shape resulting from the interference effect when eV≠0. The OMF induced photon-assisted tunneling is quite different from the ones induced by the oscillating electric field and RMF. The tunnel currents vary dramatically with the evolution of the AB magnetic flux, and the Fano-type spin and charge currents are adjusted by OMF, RMF, AB flux, gate voltage, the source–drain bias, as well as the NRT strength to generate novel Fano-type photon-assisted spin and charge currents.

A small-size pentaband hand-shaped coplanar waveguide-fed monopole antenna

A novel small-size simple structure pentaband coplanar waveguide (CPW) fed monopole antenna is presented. The antenna configuration is composed of several narrow strips that are connected to a 50-ohm CPW feed line. The length of each strip, which acting as resonance path, is λg/4 at operating frequencies. The antenna is designed to operate over the worldwide interoperability for microwave access and wireless local area networks frequency bands of 2.4, 3.3, 3.7, 5.2, and 5.8 GHz. It was found that the results of simulation and measurement agree well over each separated frequency bands. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26025

An F‐shaped printed monopole antenna for dual‐band RFID and WLAN applications

AbstractA simple microstrip fed printed monopole antenna for the radio frequency identification (RFID) and wireless local area network (WLAN) is presented.The antenna has two different resonant current paths (forming an F‐shaped structure) that support two resonances at 2.44 and 5.18 GHz, which are reserved for RFID and WLAN applications, respectively. Effectively omnidirectional radiation pattern and large impedance bandwidth has been observed both from simulation and experimental results. Impedance bandwidth for center frequency of 2.44 and 5.18 GHz are 0.65 GHz (2.12–2.77 GHz) and 0.59 GHz (4.91–5.50 GHz), respectively. The proposed antenna is simple in design and compact in size; providing broadband impedance matching, consistent omnidirectional radiation patterns and appropriate gain characteristics (&gt;1.5dBi) in the RFID and WLAN frequency regions. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26060

Localized shape resonance on silver film perforated by H-shaped and more complex shaped hole arrays

The experimental results of light transmission through periodic array of H-shaped hole and more complicated hole which is a combination of multiple U shape are demonstrated. The observations indicate that the localized shape resonance in the longest resonant length of unfolded U-shaped part of the hole always appears. However, localized modes resonant in smaller U-shaped length don't always appear. Localized mode with non-U-shaped resonant path cannot be seen in our sample. In addition, localized mode with different order and resonant path can be excited by different polarized light.

A PRINTED 2.4 GHZ/5.8 GHZ DUAL-BAND MONOPOLE ANTENNA WITH A PROTRUDING STUB IN THE GROUND PLANE FOR WLAN AND RFID APPLICATIONS

The design of a simple microstrip fed folded strip monopole antenna (FSMA) with a protruding stub in the ground plane for the application in WLAN and RFID is presented. The antenna has two resonant paths, one in the radiating element (folded strip) and the other in the protruding stub of the ground plane. It supports two resonances at 2.4 GHz and 5.81 GHz, which are the center frequencies of WLAN and RFID. Effectively consistent radiation pattern and large percentage bandwidth have been observed. The measured percentage fractional bandwidth at 2.4 GHz (2.05 GHz to 2.86 GHz) is 32.99, and the percentage fractional bandwidth at 5.81 GHz (5.55 GHz to 6.14GHz) is 10.11. The proposed antenna is simple and compact in size, providing broadband impedance matching, consistent radiation pattern and appropriate gain characteristics in the WLAN and RFID frequency regions.

A MULTI-BAND MEANDERED SLOTTED-GROUNDPLANE RESONATOR AND ITS APPLICATION OF LOW-PASS FILTER

A slotted-ground-plane meandered-slot resonator with multi-resonance characteristics and a compact lowpass fllter (LPF) by using the resonator are demonstrated in this paper. The meandered slot provides a wideband resonator with low insertion loss and very sharp cutofi frequency response. Unlike conventional design of cascading bandstop slotted-ground-plane resonators in the literature, the introduced LPF is presented, which consists of a modifled-meander slot in the ground plane, a spurred C-like slot, and a uniform microstrip transmission line with constant characteristics impedance. Two rectangular-head slots, giving an increase in the inductance, are added at the two terminals of the meandered slot for purpose of frequency reduction. An arm aperture is embedded to form another resonant path so that an additional transmission zero could be generated. In order to increase rejection capability, the slot width of one section of the meandered-slot resonator is widened. Meanwhile, a C-like slot with a spur slit is also etched inside the meandered slot to improve rejection performance. The measured insertion loss at a passband is below 0.7dB, and the rejection band over 20dB is from 2.9 to 12.0GHz.

Coherent interference induced transparency in self-coupled optical waveguide-based resonators

We propose a self-coupled optical waveguide (SCOW)-based resonator to generate an optical resonance analogous to electromagnetically induced transparency (EIT). The EIT-like effect is formed by the coherent interference between two resonance paths inherent to the SCOW resonator. For cascaded SCOW resonators, the spectrum they produce is significantly affected by the phase shift between them, with the EIT-like peak flattened or split as the two extreme cases. We also investigate the dispersion characteristics of an infinite array of SCOW resonators and show that the dispersion relation and group index in the EIT subband can be greatly changed by a small phase shift between the SCOW resonators.

Optical Imaging of Electrical Carrier Injection into Individual InAs Quantum Dots

We image the micro-electroluminescence (EL) spectra of self-assembled InAs quantum dots (QDs) embedded in the intrinsic region of a GaAs p-i-n diode and demonstrate optical detection of carrier injection into a single QD. Tunneling of electrons and holes into the QDs at bias voltages below the flat-band condition leads to a spectrum of sharp EL lines from a small number of bright spots on the diode surface, characteristic of emission from individual QDs. We explain this behavior in terms of Coulomb interaction effects and the selective excitation of a small number of QDs within the ensemble due to preferential tunneling paths for carriers.

Multipactor Effect Analysis and Design Rules for Wedge-Shaped Hollow Waveguides

A numerical model for predicting the multipactor breakdown effect in wedge-shaped hollow waveguides is presented in this paper. The computation of electromagnetic fields is based on the boundary integral-resonant mode expansion method, which provides the modal chart of hollow waveguides with any arbitrary cross section. The advantage of using wedge-shaped waveguides with respect to conventional rectangular ones is the deviation of the resonant paths of the electrons toward regions with lower voltages, thus reducing the probability of multipactor threshold for certain input power. To validate this method, our results have been compared with simulations from previous theoretical studies. Once the simulation tool is validated, it is used to predict the multipactor threshold of wedge-shaped waveguides with different symmetric inclination angles of their horizontal plates. Finally, susceptibility curves as the ones already available for rectangular waveguides are presented. These charts are useful for designing innovative waveguide geometries with improved multipactor-free working power ranges.

Resonant Auger decay of Ar2p3/2−14sand2p3/2−14pstates excited by electron impact

Auger spectra of resonantly excited $2{p}_{3/2}^{\ensuremath{-}1}4s$ and $2{p}_{3/2}^{\ensuremath{-}1}4p$ states in argon were measured by $(e,2e)$ technique. The 99.2-eV scattered electrons were detected in coincidence with ${L}_{3}--{M}_{23}{M}_{23}$ Auger electrons, and the experiment was performed at 343.6- and 344.9-eV electron impact to tune the energy loss to the energy of the dipole-allowed and the dipole-forbidden excitations, respectively. The resonant Auger spectra are obtained upon subtraction of the overlapping signal due to the outer-shell ionization, which was recorded at 340-eV electron-impact energy. The most intense groups of Auger transitions from $2{p}_{3/2}^{\ensuremath{-}1}4s (J=1,2)$ and $2{p}_{3/2}^{\ensuremath{-}1}4p (J=0,1,2,3)$ states are identified by comparison with the results of the two-step model, based on distorted-wave Born approximation with exchange and multiconfiguration descriptions of the relaxed states. The $4 s$ spectrum displays a substantially larger shake-up contribution than the one observed in photoexcitation experiments, which may be explained by the interference of the resonant decay path with the direct ionization excitation of the Ar $3p$ subshell. The majority of the observed $4p$ signal is assigned to the monopole and quadrupole excitations of the ground state.

Small-size printed loop-type antenna integrated with two stacked coupled-fed shorted strip monopoles for eight-band LTE/GSM/UMTS operation in the mobile phone

A small-size internal printed antenna formed by a loop-type antenna integrated with two stacked coupled-fed shorted strip monopoles is presented.The proposed antenna has a small uniplanar structure of 40 × 15 mm2 (600 mm2) for eight-band LTE/GSM/UMTS operation in the mobile phone. The loop-type antenna comprises a driven monopole and a coupled portion short-circuited to the system ground plane of the mobile phone; the driven monopole alone contributes a resonant mode for the antenna's upper band, whereas the driven monopole and shorted coupled portion together provide a loop-type resonant path to generate a resonant mode for the antenna's lower band. Two stacked strips are then integrated with the loop-type antenna, with the two strips coupled-fed by the driven monopole and short-circuited to the ground plane through the shorted coupled portion. That is, two stacked coupled-fed shorted strip monopoles are formed and incorporated with the loop-type antenna in an integrated configuration. The two strip monopoles contribute two additional resonant modes to incorporate those generated by the loop-type antenna to achieve the desired wide lower band (698–960 MHz) and upper band (1710–2690 MHz) for eight-band LTE/GSM/UMTS operation. Details of the proposed antenna are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1471–1476, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25257

Comparison of sea modeling approaches for vibration transmission through beam structures.

Transmission through beams can become a significant path in many structure‐borne problems, especially in aircraft or launch vehicles. Statistical energy analysis (SEA) is widely used for the vibro‐acoustic modeling of high‐frequency problems. However, in a system‐level SEA model, even at higher frequencies, some beams can exhibit low‐modal behavior and might not be a good SEA representation. Vibration transmission through beams involves both resonant and non‐resonant transmission paths. Typically the non‐resonant path is dominant at low frequencies and the resonant path at high frequencies. This paper describes various modeling approaches for describing the transmission through beams over a broad frequency range. SEA modeling techniques will be compared to the hybrid FE‐SEA method, energy flow method, and the finite element method for various beam configurations. Modeling beams under pre‐stressed conditions is also investigated.