bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adjustable compact dual‐band microstrip bandpass filter using T‐shaped resonators
Authors: Khani Shiva , Makki Seyed Vahab AL‐Din , Mousavi Seyed Mohammad Hadi , Danaie Mohammad , Rezaei Pejman 
Published: September 2017

AbstractIn this letter, a compact dual‐band bandpass filter (BPF) is designed, analyzed, and fabricated. A loop resonator loaded by two modified T‐shaped resonators, double T‐shaped resonators, and open bended stubs are applied to form the proposed configuration. The coupling spaces between the loop resonators and open bended stubs result in two passbands with the center frequencies of 2.4 GHz and 5.7 GHz. The LC equivalent circuit of the main resonator is introduced to present an analytical description. Without needing to increase the circuit size, the upper passband can be adjusted between 5.72 GHz and 6.93 GHz. The measured data indicates less than 0.64 dB and 0.76 dB insertion losses in the first and second passbands, respectively. Adjustable second center frequency, compact size, low insertion loss, good suppression level, and a symmetrical structure are the marked features of the proposed BPF. Finally, a good agreement between the simulated and measured results is observed.
A novel dual‐band tunable band‐notched antenna
Authors: Xi Lei , Zhai Huiqing , Zang Yiping , Li Long 
Published: September 2017

AbstractThis letter presents a novel dual‐band tunable band‐notched antenna. The antenna consists of a monopole ultrawideband (UWB) antenna and two kinds of novel notched structures. A tunable notched wave is obtained by adjusting the capacitance on the notched structure. Monopole antenna works well on 3.1‐10.6 GHz. The low frequency notched wave can be adjusted on the 3–4 GHz, and the high frequency band notched wave can be adjusted on the 5–6 GHz, which can avoid the influence of the WiMax and WLAN narrowband communication system on the UWB communication system, and improve the performance of the antenna system. At the same time, through the analysis of the surface current distribution of the notched antenna, the principle of the notched wave is studied. At last, a prototype of the band‐notched antenna is fabricated and measured whose simulation is consistent with the measurement.
Thermally tunable fano resonance of a conductive rubber‐based metamaterial
Authors: Qiu Kepeng , Liu Zijun 
Published: September 2017

AbstractThis article presents a thermally tunable Fano resonator obtained by asymmetrically coupling a conductive rubber‐based H‐shaped split ring resonator (SRR) and a copper C‐shaped SRR coated on a Teflon fiberglass slab substrate. Thermal tunability of the Fano resonance is provided by the temperature‐sensitive resistance property of the conductive rubber. The thermal tunability of the Fano resonance obtained from the proposed resonator structure is demonstrated by both simulation and experimental results. This study provides a novel tunable approach for designing dynamical electromagnetic modulation devices.
Cross‐range target response analysis for extreme high‐squint synthetic aperture radar
Authors: Burfeindt Matthew J. 
Published: September 2017

AbstractWe propose a formulation for predicting the cross‐range characteristics of the synthetic aperture radar (SAR) point‐spread function (PSF) for extremely high squints based on the concept of phased array factors. We demonstrate the validity of this approach by comparing theoretical predictions to PSF dimensions extracted from SAR images. The results show that the proposed approach is more robust than the conventional theory for extreme high‐squint scenarios.
A bandwidth enhancement for metamaterial microstrip antenna
Authors: Wu Wenjing , Yuan Bo , Guan Boran , Xiang Tieming 
Published: September 2017

AbstractA bandwidth enhancement for metamaterial microstrip antenna is presented for ultra‐wideband (UWB) applications. The metamaterial antenna consists of irregular figures etched on the upper patch periodically and a planar metallic ground carved by grid patterned gaps on the bottom patch. The overall dimension of the proposed antenna is
mm3. Experimental results show that the relative impedance bandwidth (–10 dB) of the proposed antenna is 168.3% with the ranging from 2.9 to 33.7 GHz, whose relative bandwidth is improved by 38.9–121.9% than the previously reported wideband ones. Its simulated reflection coefficient has a good agreement with the measured one, and its gain varies from 1.30 to 7.17 dB, meanwhile, it has a maximum radiation efficiency of 95.6% in the operating frequency band. Besides, the end‐fire directional radiation in the high frequency band is observed. Thus, the proposed antenna could be a potential candidate for UWB wireless communication systems.
Asynchronously coupled resonant junctions for diplexers and multiport filtering networks
Authors: Ogbodo Eugene A. , Wu Yun , Callaghan Peter , Wang Yi 
Published: September 2017

AbstractThis article proposes the use of asynchronously coupled resonator junctions in the design of diplexers. This is to ease the control and implementation of the external couplings at the common port of an all‐resonator‐based diplexer. A comparison study has been performed between a conventional diplexer and the proposed diplexer. To further explore the possibilities of the proposed junction technique, a four‐port multiport filtering networks was proposed and designed to function as a double diplexer. Good agreements have been achieved between the measurements of the prototype devices and the simulations.
A novel homogeneous stacked yttrium ion garnet resonator antenna for wideband application
Authors: Othman Mohamadariff , Wan Ali Wan Fahmin Faiz , Ahmad Zubir Ihsan , Ain Mohd Fadzil , Ahmad Zainal Arifin 
Published: September 2017

AbstractThe intent of this study is to realize efficient wideband DRA using unbiased low permittivity yttrium ion garnet (YIG) with excess Fe2O3. The fabricated YIG resonators with the same dimension but different ɛr are used together to produce wideband stacked YIG resonator antenna (YRA). Three stacked YIG resonators with excess Fe2O3 of 8% (YR8), 14% (YR14), and 17% (YR17) present the best YIG resonator combinations with bandwidth of 24.22%. Findings also indicate broadband radiation pattern throughout the design frequency range. The simulated and measured results are all in agreement. In conclusion, this work offers an improved and efficient YRA using YIG resonator with excess Fe2O3.
A novel very wideband integrated antenna system for 4G and 5G mm‐wave applications
Authors: Ikram M. , Sharawi M. S. , Shamim A. 
Published: September 2017

AbstractIn this work, a novel very wideband 4‐element monopole based multiple‐input multiple‐output (MIMO) antenna system with single connected antenna array (CAA) is presented. The CAA is based on a single slot which is etched on the ground plane. A 2 × 1 power divider/combiner is used to excite the slot to act as a CAA. The proposed design covers the 4G bands between 1850 and 3700, and the 28 GHz 5G band. The covered bandwidths are 1462 and 240 MHz from 1843 to 3305 MHz and 3500 to 3740 MHz, respectively, for 4G applications. A bandwidth of 1.22 GHz from 27.5 to 28.72 GHz is obtained for 5G applications. The proposed antenna system is designed on a double layer RO4350B substrate with height of 0.76 mm and dielectric constant of 3.5. The total size of the design is 115 × 65 × 0.76 mm3. It is compact, low profile and suitable for wireless handheld devices. The MIMO performance metrics such as isolation and ECC are evaluated and good agreement between simulations and measurements is achieved.
A miniaturized dual‐band microstrip patch antenna using a symmetrical composite right/left handed unit
Authors: Zhang Chaoqun , Gong Jianqiang , Wang Yuhao 
Published: September 2017

AbstractIn this article, a miniaturized dual‐band microstrip patch antenna is proposed, which is in essence a composite right/left handed unit with symmetrical slots and metallic pins. An effective design procedure is presented. The ratio of the higher center frequency to the lower one can be varied from 1.01 to 1.59 by adjusting specified parameters. A typical model has been fabricated and measured to validate the design concept. The model shows a dual‐frequency function and patch‐like radiations at 7.1 GHz for n = −1 mode and at 8.42 GHz for n = 0 mode respectively, both providing wide coverage angles in half space.
A 2–22 GHz CMOS wideband distributed power amplifier
Authors: Zhang Ying , Ma Kaixue 
Published: September 2017

AbstractThis article presents a novel wideband distributed power amplifier (DPA) implemented in a 0.18 μm CMOS technology. The DPA consists of a preamplifier and a medium‐power power amplifier (PA), and both of them are respectively composed of two distributed amplifiers (DAs), which have separate input artificial transmission lines (ATLs) but with their output ATLs shared to achieve wide frequency band. In the medium‐power PA, the large‐signal multigated transistor technology is applied to further improve the linear output power. Measurement results show that the DPA achieves 10.2 dB average associated gain from 2.5 to 22 GHz. The output power at 1‐dB output compression point (OP1dB) is more than 8 dBm over the frequency of 2–22 GHz, and the peak OP1dB is 12.6 dBm with the power‐added efficiency of 7.2% at 6 GHz.
Linear variable filter enabling an enhanced wavelength gradient based on shadow‐mask sputtering
Authors: Ji Peng , Gao Song , Park Chul‐Soon , Lee Sang‐Shin , Choi Duk‐Yong 
Published: September 2017

AbstractA linear variable filter (LVF) that improves the wavelength gradient is proposed, and a sample is manufactured using a radio frequency sputtering technique with the help of a vertical shadow mask, which simplifies the fabrication process. The LVF is based on a metal‐dielectric‐metal Fabry–Perot etalon, wherein the dielectric cavity is tapered in thickness along the device so that the resonance wavelength can be continuously tuned at various positions. The produced device shows a filtering range from 443 nm to 602 nm over a distance of 16 mm, which corresponds to a wavelength gradient of 10 nm/mm. The measured spectra exhibited, on average, a peak transmission of 39% and a spectral bandwidth of 46 nm.
A bandwidth and gain enhancement for microstrip antenna based on metamaterial
Authors: Yuan Bo , Zheng Yan He , Zhang Xiao Hong , You Bin , Luo Guo Qing 
Published: September 2017

AbstractAn ameliorated ultrawide band (UWB) and high‐gain microstrip antenna based on planar metamaterial is presented and discussed in this paper. The proposed antenna with a compact size of 32 × 28 × 0.794 mm3 has mesh‐shaped patch and patterned ground plane with crossed strip gaps. By means of novel planar metamaterial structure, impedance bandwidth and gain own a significant improvement. The simulations show that the antenna has a super‐wide band (less than −10 dB), from 3.06 GHz to 36.4 GHz, covering the entire UWB frequency band (from 3.1 GHz to 10.6 GHz) set by FCC. Within the operating band of concern, the antenna gain can reach as high as 8.02 dB. Due to the surface wave coming from the patterned patch and ground plane, the antenna presents end‐fire directional radiation in the higher frequency region. To validate the simulation results, a prototype is fabricated and measured. And the measured results are in good agreement with the simulation results. It is obvious that advantages mentioned above will enable the proposed antenna to be well applied in the short‐range wireless communication system.
Experimental characterization of the impedance of balanced UHF RFID tag antennas
Authors: Stoumpos C. K. , Anagnostou D. E. , Chryssomallis M. T. 
Published: September 2017

AbstractAn experimental procedure for the accurate characterization of the impedance of balanced tag antennas for RFID applications is reintroduced. The balanced devices that are characterized are modeledas 2‐port networks and their impedance is derived from network parameters, through a rarely used equation that is preferred because it accounts for the losses of non‐reciprocal structures such as imperfect test fixtures or baluns. The measurements are conducted using a test fixture for the proper excitation of the balanced devices, and its effects are removed by shifting the measurement plane to the plane of the device under test. The accuracy of the proposed method is demonstrated through the measurement of the impedance of a balanced dipole antenna, and is complemented by the measurement of the RFID ASIC chip. The experimental characterization of the impedance of an RFID tag antenna constitutes a secure way to achieve conjugate matching between the 2 devices (ie, the antenna and the RFID chip), and finally enhance the reading range of the RFID tags. Also, since RFID tags are designed to be placed directly on different surfaces, the proposed procedure is further evaluated by mounting the antenna onto 2 more surfaces.
A cryogenic measurement setup for characterization microwave devices
Authors: Rybalko Oleksandr 
Published: September 2017

AbstractA cryogenic measurement setup for characterization microwave devices from room to cryogenic temperatures is presented. The setup allows testing microwave devices at variable temperatures ranging from 300 to 77 K. Frequency doubler (94/188 GHz) has been cooled to 77 K and peak efficiency of 32% at an input‐power level of 207 mW is achieved. For verification experimental results the millimeter‐wave GaAs Schottky barrier diode model is developed for CAD simulator. The simulated peak efficiency is 37% at 77 K. The estimation of simulated and measured data of the doubler efficiency versus temperature has the same trend from 77 to 300 K which confirmed the cryogenic measurement setup applicability.
Circularly polarized 2‐arm spiral antenna for 60‐GHz applications
Authors: Zhu Jianfeng , Liao Shaowei , Li Shufang 
Published: September 2017

AbstractA wideband circularly polarized (CP) 2‐arm spiral antenna is designed for 60‐GHz applications in this letter. The proposed antenna is implemented on a single layer with spiral printed on the top surface of the substrate and fed in a differential way through 2 metallized via holes. Unidirectional radiation is achieved thanks to the presence of the ground plane, which is placed with a distance of one‐quarter of the guided wavelength to the spiral. A cavity is mounted on the top of the spiral antenna to suppress the surface wave propagate along the substrate as well as to improve the antenna gain. Experimental results show that the prototype achieves the −10‐dB impedance bandwidth from 55.2 to 66 GHz with circular polarization. The peak gain at boresight is 9.5 dBi occurring at 63 GHz and the radiation patterns are stable over the operating frequency band.
Ultrawide isolation bandwidth compensated power divider for UWB applications
Authors: Uchendu Iyemeh E. , Kelly James R. 
Published: September 2017

AbstractThis article presents design analyses for achieving an ultrawide isolation bandwidth compensated power divider (CPD). The CPD offers improvement in complexity, size, and insertion when compared with alternative techniques for increasing isolation bandwidth. A prototype CPD with −15 dB isolation bandwidth of 114% was fabricated and measured to validate the analyses.
Frequency independent 180° phase shifter based on UWB coupled sections
Authors: Tebache Soufiane , Ghanem Farid , Belouchrani Adel , Mansoul Ali 
Published: September 2017

AbstractIn this article, a novel Ultra‐Wideband (UWB) 180° planar phase shifter is designed and fabricated. The proposed design is mainly based on coupled sections which are realized by inserting slots into the common ground plane of the multilayer circuit. Two identical structures, leading to discard parameters that disturb the output phase shift, are introduced in the design. To get 180° phase difference shift, via holes are used to perform a short circuit in one of the two coupled sections. Theoretical analysis based on four port network is presented to explain the characteristics of the proposed design. Further, experimental measurements are performed and compared with simulation results to validate the proposed approach. Hence, a good simulated to measured agreement is obtained.
Design and fabrication of a small‐form transmitter optical subassembly for 100 Gbps short reach optical interconnect
Authors: Liu Fengman , He Huimin , Xue Haiyun , Song Mangu , Dai Fengwei , Sun Yu , Wu Peng , Cao Liqiang 
Published: September 2017

AbstractA high‐coupling‐efficiency and convenient‐integration transmitter optical subassembly for 25 Gbps small‐form transceiver is developed in this paper. In the structure, the VCSEL is vertically mounted on the silicon substrate by the flip‐chip method to enable direct and passive alignment with the fibers plugging in the fiber guide holes on the silicon substrate. By the optical simulation, the maximum coupling efficiency of VCSEL is −0.38 dB. The vertical electrical pads of the VCSEL are connected to the horizontal wire‐bonding pads on silicon substrate by the 90°‐bend GS micro strip lines. Thus, the interconnection between the transmitter optical subassembly and the electrical PCB board is conveniently realized by the low‐cost wire‐bonding method. The electrical performance of the 90°‐bend GS micro strip lines on the optical subassembly is also evaluated by the 3D electromagnetic simulation. In order to verify the transmission performance of the transmitter optical subassembly, it is integrated with an electrical board using bonding wires, and then the optical performance of the transmitter is measured. By the measurement, the optical subassembly can operate up to 25 Gbps per channel.
Procedure to measure real time latency using software defined radio in a W‐band fiber‐wireless link
Authors: Rico‐Martínez Mónica , Morales Alvaro , Mehmeri Victor , Puerta Rafael , Varón Margarita , Monroy Idelfonso Tafur 
Published: September 2017

AbstractReducing latency is a major challenge for current telecommunications systems. 5G networks are envisioned to achieve end‐to‐end latencies below 1 ms, thus enabling the Internet of Things (IoT) evolution and new applications such as Tactile Internet. In this article, we present a new procedure to measure real time latency in hybrid optical‐wireless links. We obtained 2 ms end to end latency using Software Defined Radio to measure latency in a physical setup. We tested the procedure on W‐band fiber‐wireless link and validated the results against PING over GRE tunnel.
Improved quantitative 90Y bremsstrahlung SPECT/CT reconstruction with Monte Carlo scatter modeling
Authors: Dewaraja Yuni K. , Chun Se Young , Srinivasa Ravi N. , Kaza Ravi K. , Cuneo Kyle C. , Majdalany Bill S. , Novelli Paula M. , Ljungberg Michael , Fessler Jeffrey A. 
Published: September 2017

PurposeIn 90Y microsphere radioembolization (RE), accurate post‐therapy imaging‐based dosimetry is important for establishing absorbed dose versus outcome relationships for developing future treatment planning strategies. Additionally, accurately assessing microsphere distributions is important because of concerns for unexpected activity deposition outside the liver. Quantitative 90Y imaging by either SPECT or PET is challenging. In 90Y SPECT model based methods are necessary for scatter correction because energy window‐based methods are not feasible with the continuous bremsstrahlung energy spectrum. The objective of this work was to implement and evaluate a scatter estimation method for accurate 90Y bremsstrahlung SPECT/CT imaging.MethodsSince a fully Monte Carlo (MC) approach to 90Y SPECT reconstruction is computationally very demanding, in the present study the scatter estimate generated by a MC simulator was combined with an analytical projector in the 3D OS‐EM reconstruction model. A single window (105 to 195‐keV) was used for both the acquisition and the projector modeling. A liver/lung torso phantom with intrahepatic lesions and low‐uptake extrahepatic objects was imaged to evaluate SPECT/CT reconstruction without and with scatter correction. Clinical application was demonstrated by applying the reconstruction approach to five patients treated with RE to determine lesion and normal liver activity concentrations using a (liver) relative calibration.ResultsThere was convergence of the scatter estimate after just two updates, greatly reducing computational requirements. In the phantom study, compared with reconstruction without scatter correction, with MC scatter modeling there was substantial improvement in activity recovery in intrahepatic lesions (from > 55% to > 86%), normal liver (from 113% to 104%), and lungs (from 227% to 104%) with only a small degradation in noise (13% vs. 17%). Similarly, with scatter modeling contrast improved substantially both visually and in terms of a detectability index, which was especially relevant for the low uptake extrahepatic objects. The trends observed for the phantom were also seen in the patient studies where lesion activity concentrations and lesion‐to‐liver concentration ratios were lower for SPECT without scatter correction compared with reconstruction with just two MC scatter updates: in eleven lesions the mean uptake was 4.9 vs. 7.1 MBq/mL (P = 0.0547), the mean normal liver uptake was 1.6 vs. 1.5 MBq/mL (P = 0.056) and the mean lesion‐to‐liver uptake ratio was 2.7 vs. 4.3 (P = 0.0402) for reconstruction without and with scatter correction respectively.ConclusionsQuantitative accuracy of 90Y bremsstrahlung imaging can be substantially improved with MC scatter modeling without significant degradation in image noise or intensive computational requirements.
Simultaneous detection of glutathione and lactate using spectral editing at 3 T
Authors: Chan Kimberly L. , Snoussi Karim , Edden Richard A.E. , Barker Peter B. 
Published: September 2017

Two spectral editing techniques for the simultaneous detection of glutathione (GSH) and lactate (Lac) in the human brain at 3 T are described and evaluated. These methods, ‘sMEGA’ (sinc‐MEscher and GArwood) and ‘DEW’ (Double Editing With), were optimized to detect GSH and Lac simultaneously at 3 T using density‐matrix simulations and validation in phantoms. Simulations to test for co‐edited metabolites within the detected GSH region of the spectrum were also performed. In vivo data were acquired in the midline parietal region of seven subjects using both methods, and compared with conventional MEGA‐PRESS (MEscher and GArwood‐Point RESolved Spectroscopy) acquisitions of GSH and Lac. Simulations and phantom experiments showed that sMEGA and DEW had a high editing efficiency for both GSH and Lac. In the phantom, the editing efficiency of GSH was >88% relative to a conventional GSH MEGA‐PRESS acquisition, whereas, for Lac, the editing efficiency was >95% relative to a conventional Lac MEGA‐PRESS acquisition. Simulations also showed that the editing efficiency of both methods was comparable with separate MEGA‐PRESS acquisitions of the same metabolites. In addition, simulations and in vivo spectra showed that, at a TE of 140 ms, there was a partial overlap between creatine (Cr) and GSH peaks, and that N‐acetyl aspartate/N‐acetyl aspartyl glutamate (NAA/NAAG) were sufficiently resolved from GSH. In vivo measurements showed that both sMEGA and DEW edited GSH and Lac reliably with the same editing efficiency as conventional MEGA‐PRESS acquisitions of the same metabolites, with measured GSH integrals of 2.23 ± 0.51, 2.31 ± 0.38, 2.38 ± 0.53 and measured Lac integrals of 1.72 ± 0.67, 1.55 ± 0.35 and 1.53 ± 0.54 for MEGA‐PRESS, DEW and sMEGA, respectively. Simultaneous detection of GSH and Lac using sMEGA and DEW is possible at 3 T with high editing efficiency.