Longer Strip Research Articles

Development of double SiPM readout method for ILD scintillator electro-magnetic calorimeter

The electro-magnetic calorimeter concept using plastic scintillator (Sc-ECAL) is being developed for detectors at future electron-positron colliders such as ILC . The Sc-ECAL is based on 5 × 45 × 2 mm3 plastic scintillator strips readout by SiPMs. This can realize a virtual 5 × 5 mm2 cell segmentation which is required for particle flow calorimetry at ILC detectors. However, there are some issues such as signal/noise ratio and ghost hits. A scintillator strip design based on double SiPM readout is being developed where a twice longer strip (5 × 90 × 2 mm3) is read out by two SiPMs, one at each end. The performance of Sc-ECAL can be improved in various aspects by this method. The performance of the double SiPM readout was tested with a prototype setup. The position dependence of the light yield for a 90 mm-long scintillator strip was measured. A higher light yield and reasonably uniform response were observed with the sum of the two SiPM readouts. The hit position was reconstructed by using the charge and time difference between the two readouts. A position resolution of 20 mm was obtained.

Design Simulation and Fabrication of a Dual Band Frequency Reconfigurable Monopole Antenna for Wi-Fi and WiMAX Applications

Nowadays, wireless systems require compact multi band antennas that can dynamically change some of its fundamental parameters such as frequency band, polarization and radiation pattern. The novelty of the proposed work lies in using two conducting strips that are perpendicular to each other. The longer strip resonates at 2.4 GHz and the shorter strip resonates at 3.5 GHz. The length and width of the Ground plane is made equal to length of the main arm and length of the side arm respectively. The results are obtained by simulating the antenna structure using simulation tool Ansoft HFSS v15.0. The Simulated antenna Gains were 6.2364 dBi and 7.1758 dBi for frequencies of 2.4 GHz and 3.5 GHz respectively. The antenna dimensions are 50 × 25 × 1.6 mm3 on a 1.6 mm thick FR-4 substrate.

A Reconfigurable Antenna for LTE/WWAN Mobile Handset Applications

In this letter, a reconfigurable antenna for mobile handset applications is proposed. This antenna mainly consists of a longer strip, a shorter strip, and a p-i-n diode. Coupling is generated at the gap between the longer strip and the shorter strip. Depending on the different states of the p-i-n diode, the degree of coupling between them is controlled, and the fundamental resonant frequency of the proposed antenna is adjusted. As a result, the proposed antenna in the low band covers the LTE700/GSM850/900 bands. The high band is formed by combining higher-order mode of the longer strip and quarter-wavelength mode of the shorter strip to cover the GSM1800/1900/UMTS/LTE2300/2500 bands.

Small-size printed strip MIMO antenna for next generation mobile handset application

A compact printed multiple-input multiple-output (MIMO) antenna with an embedded chip inductor is proposed for a 4G mobile handset application. The proposed MIMO antenna consists of a longer strip with an embedded chip inductor and a shorter radiating strip. The longer radiating strip with a 15-nH embedded chip inductor has a length of only about 42 mm (∼ 0.1 wavelength at 0.77 GHz), but it supports a wide resonant mode at 0.77 GHz for long-term evolution (LTE) Band 13 and at 2.35 GHz for WiBro operation. The shorter radiating strip has a length of about 15 mm (about 0.1 wavelength at 2.0 GHz) and provides a wide resonant mode at about 2 GHz for WCDMA operation. The two radiating strips occupy a small printed area of about 720 mm2 on the system circuit board of a mobile handset. The proposed MIMO antenna has an isolation of approximately −17 dB at LTE band 13 and the envelope correlation coefficient (ECC) of the two antennas is always lower than 0.4 over the whole LTE band 13. To evaluate the performance of the proposed antenna, key performance parameters such as the total efficiency, ECC, mean effective gain (MEG), and the MEG ratio are analyzed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:348–352, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25746

Coupled-fed loop antenna with branch radiators for internal LTE/WWAN laptop computer antenna

A new antenna structure of internal long-term evolution/wireless wide area network (698–960/1710–2690 MHz) laptop computer antenna formed by a coupled-fed loop antenna connected with two branch radiators is presented. The two branch radiators consist of one longer strip and one shorter strip, both being efficient radiators and contributing multiresonant modes to greatly enhance the bandwidth of the antenna. The antenna's lower band is formed by a dual-resonant mode mainly contributed by the longer branch strip, while the upper band is formed by three resonant modes contributed respectively by one higher-order resonant mode of the longer branch strip, one resonant mode of the coupled-fed loop antenna alone, and one resonant mode of the shorter branch strip. The antenna's lower and upper bands can therefore cover the desired 698–960 and 1710–2690 MHz bands, respectively. The proposed antenna is suitable to be mounted at the top shielding metal wall of the display ground of the laptop computer and occupies a small volume of 4 × 10 × 75 mm3 above the top shielding metal wall, which makes it promising to be embedded inside the casing of the laptop computer as an internal antenna. Details of the proposed antenna are studied in the paper. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2662–2667, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25556

Dual band–rejected microstrip antenna for WiMAX/WLAN applications

AbstractIn this article, we propose a novel design to obtain dual band–rejected characteristics in printed microstrip antenna.First, an ultrawide operating band from 2.15 GHz to about 6.50 GHz is achieved by locating the rectangular radiating patch above a larger rectangular notch cut in the finite ground plane edge. Two folded strips with different length protrude from the patch corner with null surface current to introduce dual rejected band. The longer strip and shorter strip are independently associated with lower and upper rejected band. By suitable adjustment in strip lengths, two rejected bands centered at 3 and 4.7 GHz are successfully introduced. Also, a triband operation for 2.5/3.5/5.5 GHz WiMAX and 2.4/5.2/5.8 GHz WLAN applications is achieved for the proposed microstrip antenna. Details of the design considerations are presented, and results of the implemented prototype are discussed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1901–1905, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25312

Multi‐band chip antenna for WiMAX applications

AbstractA novel chip antenna for dual‐/tri‐band operation is presented in this article.The design consists of a pair of forked metal strips with different lengths. The longer strip is folded onto an FR4 base to simultaneously introduce the quarter‐ and half‐wavelength modes as the first two operating bands. By varying the included angle between the sections of strip on the opposite base layers, the frequency ratio of the first two operating modes is adjusted over a large range of 1.34–2.29. In addition, the shorter excited strip introduces the quarter‐wavelength mode as the third operating band. The tri‐band operation with a small dimension of 13 × 5 × 0.8 mm3 for 2.5/3.5/5.5 GHz WiMAX applications is implemented. Experimental results show that the proposed antenna has good omnidirectional radiation patterns and steady antenna gains over all operating bands. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1286–1290, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25211

Very small size printed monopole with embedded chip inductor for 2.4/5.2/5.8 GHz WLAN laptop computer antenna

AbstractA very small size planar two‐strip monopole printed on a thin (0.4 mm) FR4 substrate for 2.4/5.2/5.8 GHz triple‐band WLAN operation in the laptop computer is presented. With the aid of an embedded chip inductor of 5.6 nH in the longer strip of the printed monopole, a much reduced strip length for obtaining the resonant mode at about 2.4 GHz is obtained, thereby leading to a much reduced size of the antenna for the desired WLAN operation. When the antenna is mounted along the top edge of the display ground, it shows a height of 9 mm and a length of 6 mm only, which is about the smallest among the triple‐band WLAN laptop computer antennas that have been reported. Details of the proposed antenna are described. Results of the fabricated prototype, including the user's hand effects on the antenna performances, are presented. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 171–177, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24843

High-frequency characterization of Permalloy nanosized strips using network analyzer ferromagnetic resonance

We report on the dynamic properties of Permalloy nanostrips at gagahertz frequencies. The thickness of the strips is 100nm, strip width is 300nm, strip spacing is 1μm, and length is 0.3–100μm; aspect ratios are 1:1, 1:2, 1:3, 1:5, 1:10, and 1:333. The dynamic behavior was studied by network analyzer ferromagnetic resonance (FMR) using Permalloy strips on a coplanar waveguide in flip-chip geometry. The FMR mode frequencies (fr) can be controlled by the aspect ratio as well as by the applied magnetic field (H). In longer strips (1:10 and 1:333), the excitation frequencies show a soft mode behavior (Heff=990Oe) when the field is along the hard axis. However, along the easy axis (along the strip length), fr increases with applied field. At a field of 3kOe, fr values are almost independent of aspect ratio along the easy axis except for the 1:1 strip. Along the hard axis, the frequencies are strongly dependent upon the aspect ratio. We also observed that the frequency linewidths of the strips are dependent on the aspect ratio.

Advanced Micro-Heat Exchangers for High Heat Flux

Three micro-heat exchangers for use in a liquid cooling system with a long offset strip, short offset strip, and chevron flow path based on the traditional heat transfer enhancement concepts were designed and tested. A straight channel heat exchanger was also made for comparison. The liquid crystal thermography method described by Lin and Yang (2005) was used to observe the flow and temperature distributions in the micro-heat exchangers. The test results show that the chevron channel heat exchanger provides the lowest thermal resistance. However, its pressure drop is also the highest, approximately five times higher than that for other three heat exchangers. The offset strip heat exchangers provide better thermal performance than does the straight channel heat exchanger. The performance of the heat exchanger with the shorter strip is better than that of heat exchanger with longer strip. From the above results, all of the three micro-heat exchangers with conventional heat transfer enhancement showed less thermal resistance than the straight channel heat exchanger. The conventional heat transfer techniques may be effectively applied in the high-flux micro-heat exchanger design.

Cleopatra's Pyramid

each end of two of the strips and completing octahedral surfaces with the triangles at the ends of the longer strip. This deltahedron is a pile of octahedra. On a pile of six octahedra, each strip twists through 3600. Now, the inradius of a regular octahedron is e/V6; and in FIGURE 3, OD = OA/2 = e/2V3. Hence, in a pile of k octahedra a right circular cylinder of radius e/2V3 and length 2ke/V6 can be inscribed. The HHL and LLH forms are mirror images of each other, and are bona fide deltahedra. The HHL form twists to the right; and the LLH form twists to the left. When each strip contains 12 triangles, the twist is through 3600. If each strip contains the same odd number of triangles, the model has an open face at one end which may be closed by adding an additional triangle to one strip. If each strip contains 2n triangles, the spiral deltahedron consists of a pile of (n 1) concave octahedra capped at each end with a regular tetrahedron. (A concave octahedron with equilateral triangular faces consists of three regular tetrahedra with a common edge.) It follows that the volume of a spiral deltahedron is given by (V2e'/12)[2+ 3(n 1)] or \/2e3(3n 1)/12. The dihedral angles of spiral deltahedra are variously 70?32', 141?4', and the reentrant 211?36'. These spiral deltahedra may also be considered to be a special piling of regular tetrahedra or of regular tetrahedra and triangular dipyramids. A fuller appreciation of these deltahedra can be gained by actually constructing models.

Séparation niobium-tantale contribution à l'étude de l'électrophorése sur papier

A study has been made of the separation of Nb and Ta on a micro-scale by paper electrophoresis, using oxalic and citric complexes and different buffer solutions. A fairly good separation is obtained by using oxalic complexes and, as buffer solution, a mixture of citric acid and potassium citrate of pH 3.42 and ionic strength 0.4. Different factors influencing the displacement of ions by paper electrophorcsis have been examined. It is shown that, if saturation currents are minimized, the displacement is practically proportional to the time of electrophoresis, and more difficult separations become possible using longer strips.