| 1. |
- Ahmad, Ashfaq, et al.
(författare)
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Design, Fabrication, and Measurements of Extended L-Shaped Multiband Antenna for Wireless Applications
- 2018
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Ingår i: Applied Computational Electromagnetics Society Journal. - : Applied Computational Electromagnetics Society (ACES). - 1054-4887. ; 33:4, s. 388-393
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Tidskriftsartikel (refereegranskat)abstract
- This article expounds a multi-band compact shaped antenna, which is based on CPW ground plane. FR-4 with a thickness of 1.6 mm is used as a substrate for the proposed antenna. The proposed antenna is capable of operating at 1.56 GHz for (Global Positioning System), 2.45 GHz (Wireless Local Area Network) and 4.49 GHz (Aeronautical Mobile Telemetry (AMT) fixed services). The efficiency at 1.56, 2.45, and 4.49 GHz is 79.7, 76.9 and 76.7%, respectively. The VSWR of the presented antenna is less than 1.5 at all the desired resonance modes, which confirms its good impedance matching. The performance of the proposed antenna is evaluated in terms of VSWR, return loss, radiation pattern and efficiency. CST (R) MWS (R) software is used for simulations. In order to validate the simulation results, a prototype of the designed antenna is fabricated and a good agreement is found between the simulated and measured results.
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| 2. |
- Ali, Amjad, et al.
(författare)
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RFID Humidity Sensor Tag for Low-cost Applications
- 2017
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Ingår i: APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL. - : APPLIED COMPUTATIONAL ELECTROMAGNETICS SOC. - 1054-4887. ; 32:12, s. 1083-1088
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a low-cost, flexible, chipless Radio Frequency Identification (RFID) tag for humidity monitoring applications. The tag exhibits moisture sensing feature within a compact geometrical dimension of 20mm x 17.6mm. The design is loaded with 12 resonators, where each resonator represents 1 bit in the frequency domain. For the designed 12-bit tag, 11 inverted C-shaped resonators are dedicated for encoding 11-bit information in their spectral signature. An integrated meandered-shaped resonator, covered with moisture sensitive Kapton (R) HN film, functions as a 1-bit moisture sensor. It is deployed for monitoring relative humidity (RH) levels, simultaneously. The passive RFID tag is realized on Taconic TLX-0 and has an operational bandwidth of 2.62 GHz. Furthermore, the design is modeled and analyzed for multiple substrates. The performance of the sensor tag for various humidity levels indicates that it is a potential solution for inexpensive sensing applications.
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| 3. |
- Daroui, Danesh, et al.
(författare)
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Efficient PEEC-based simulations using reluctance method for power electronic applications
- 2012
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Ingår i: Applied Computational Electromagnetics Society Journal. - 1054-4887. ; 27:10, s. 830-841
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a partial element equivalent circuit (PEEC)-based solver that has been accelerated to exploit the massively parallel structure of graphics processing unit (GPU) technology, in order to employ a reluctance-based method in an efficient way. A grouping algorithm is also presented which makes reluctance calculation efficient, suitable for GPUs, and feasible even for very large problems. It has been shown that by using the reluctance method, the coefficient matrix in the system equation can be safely sparsified whilst the required accuracy is maintained. Because the calculation of the reluctance matrix includes matrix inversion, which is a task with high computational complexity, GPUs as cooperative units are utilized to reduce computational costs by taking advantage of parallelism. Two test models have been simulated and analyzed to benchmark the solver, and the results have been compared with the previously developed solver. Furthermore, analyzing the results reveals that the reluctance method makes it possible to use a considerably sparser system and thereby solve large problems by decreasing the memory demands and the solution time. It is also proven that the solution is reliable and accurate, whereas the problem has become noticeably smaller.
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| 4. |
- Daroui, Danesh, et al.
(författare)
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Parallel implementations of the PEEC method
- 2010
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Ingår i: Applied Computational Electromagnetics Society Journal. - 1054-4887. ; 25:5, s. 410-422
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the first parallel implementation of a partial element equivalent circuit (PEEC) based electromagnetic modelling code suitable for solving general electromagnetic problems. The parallelization is based on the GMM++ and ScaLAPACK packages which are cross-platform libraries available for major operating systems. The parallel PEEC solver has been tested on several high performance computer systems. Large structures containing over 250 000 unknown current and voltage basis functions were successfully analyzed for the first time with a general PEEC-solver. The numerical examples are of orthogonal type, studied both in the time and frequency domain, for which memory, performance, and speed-up results are presented.
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| 5. |
- Javed, Aisha, et al.
(författare)
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A Bowtie Slotted Quad-Band Notched UWB Antenna with Defected Ground Structure
- 2019
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Ingår i: APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL. - : APPLIED COMPUTATIONAL ELECTROMAGNETICS SOC. - 1054-4887. ; 34:11, s. 1725-1730
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Tidskriftsartikel (refereegranskat)abstract
- A novel compact bowtie slotted circular patch antenna with quad-band notched characteristics is demonstrated in this work. The presented prototype is ascertained on FR-4 substrate. Initially, an Ultra-Wideband (3.1-10.6 GHz) antenna is achieved. Later, undesirable bands between 3.55-5.16, 5.52-5.73, 6.44-6.78 and 7.61-10.6 GHz are eliminated by incorporating slots in the patch. By proper optimization of the patch as well as ground plane, four resonant bands are achieved between 2.56-3.53, 5.22-5.5, 5.7-6.4 and 6.81-7.53 GHz supporting LTE2500, WiMAX, WLAN, and X-band applications. For good impedance matching, the antenna employs a very unique bat-shaped defected ground plane structure. The peak gain of 3.7 dB is obtained by the proposed radiator. A good agreement is observed between the measured and simulated results.
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| 6. |
- Javed, Aqsa, et al.
(författare)
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Miniaturized cross-lines rectangular ring-shaped flexible multiband antenna
- 2019
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Ingår i: Applied Computational Electromagnetics Society Journal. - : Applied Computational Electromagnetics Society (ACES). - 1054-4887. ; 34:5, s. 625-630
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Tidskriftsartikel (refereegranskat)abstract
- A compact, flexible antenna for wireless applications, i.e., WLAN/WiMAX/Wi-Fi, UMTS2100, C-Band, and DSRC is presented. The quad-band antenna is designed and analyzed in terms of efficiency, gain, radiation pattern, return loss, and VSWR. The optimized design consists of a CPW fed rectangular ring patch with the semi-circular ground. The cross-lines and the semicircular ground is investigated to ascertain the multiband effect. A concept of inset feed mechanism is also interpolated to enhance impedance matching. The framed antenna is examined under the bent condition as well. The reported work is an apt candidate for the proposed applications because of its high efficiency of 95% with a peak gain of 3.22 dBi along with VSWR less than 2. With stable radiation pattern and bandwidth, there is a justified concurrence between simulated and measured results.
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| 7. |
- Khan, Aamir, et al.
(författare)
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A Compact Quad-band CPW-fed Planar Resonator for Multiple Wireless Communication Applications
- 2017
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Ingår i: Applied Computational Electromagnetics Society Journal. - : The Applied Computational Electromagnetics Society (ACES). - 1054-4887. ; 32:11, s. 1001-1007
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a low-cost, compact antenna with coplanar waveguide (CPW) feed line for multiband wireless applications. The presented multiband radiator is envisioned for integration into microwave circuits and portable RF devices. The prototype is realized on 1.6 mm thick readily available FR4 substrate with a compact geometrical size of 24x32 mm(2). The acquired quad-bands are centered at: 2.45, 3.5, 5.2 and 5.8 GHz justifying the appropriateness of the proposed radiator for the WLAN and WiMAX applications, as well as Bluetooth and ISM wireless standards. From the aspect of integration into transportable handheld devices and system designing, the presented compact antenna illustrates more expandability and flexibility. The radiation characteristics measured in the E and H-planes for desired operating frequencies are monopole-like and omni-directional, respectively. A sufficient gain is also achieved. Simulated as well as experimental results exhibit agreeable behavior.
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| 8. |
- Khan, U. H., et al.
(författare)
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A novel asterisk-shaped circularly polarized RFID tag for on-metal applications
- 2016
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Ingår i: Applied Computational Electromagnetics Society Journal. - : Applied Computational Electromagnetics Society (ACES). - 1054-4887. ; 31:9, s. 1035-1042
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Tidskriftsartikel (refereegranskat)abstract
- An asterisk-shaped, metal-mountable RFID tag with a minuscule footprint is presented. The proposed design makes use of multiple asymmetric slots patterned in a cross-shaped fashion to achieve circular polarization. The structure is excited capacitively using a terminally-grounded, T-shaped feed line positioned within the slots. This peculiar arrangement permits the attainment of circular polarized radiation characteristics over a wide band of operation. Impedance matching, antenna size reduction and read range enhancement are the additional advantages offered by the embedded feed line. The final design is realized on a commercially available FR-4 substrate over dimensions of 40 x 40 mm2 yielding an impedance bandwidth and an axial ratio bandwidth of 37 MHz and 20 MHz, respectively. Improvement in antenna gain (and consequently in the read range) is reported upon mounting the tag on metallic surfaces.
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| 9. |
- Kildal, Per-Simon, 1951, et al.
(författare)
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The PMC-Amended DB Boundary - A Canonical EBG Surface
- 2011
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Ingår i: Applied Computational Electromagnetics Society Journal. - 1054-4887. ; 26:2, s. 96-108
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Tidskriftsartikel (refereegranskat)abstract
- Replacing realistic materials and structures by their ideal counterparts, canonical surfaces, is of great interest for initial and conceptual electromagnetic (EM) studies. The recently introduced DB boundary is defined by a set of simple boundary conditions forcing the normal components of the D- and B- fields to be zero at the boundary. We show that this DB boundary produces many 2-D scattering results that are similar to how practical so-called electromagnetic bandgap (EBG) surfaces behave within the bandgap. Still, it is not directly useable as a canonical EBG surface, because, as we demonstrate in this paper, it is incomplete, creating an anomaly for normal incidence which causes unphysical field solution for 3-D field problems. We have removed this anomaly by introducing the PMC-amended DB boundary. This works in the same way as a practically realized EBG surface for both 2-D and 3-D problems within the bandgap, and is therefore a canonical EBG surface.
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| 10. |
- Kishk, A., et al.
(författare)
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Numerical Prepackaging with PMC Lid - Efficient and Simple Design Procedure for Microstrip Circuits Including the Packaging
- 2012
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Ingår i: Applied Computational Electromagnetics Society Journal. - 1054-4887. ; 27:5, s. 389-398
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents an efficient method for the design of printed microstrip circuit with packaging in mind, referred to as numerical prepackaging with a perfectly magnetic conductive (PMC) lid. The method comprises making the design including the packaging from the start by using a PMC lid, rather than first designing the open-aired circuit; and thereafter, considering the packaging effect and the often required retuning of the circuits themselves. The advantage is that no parallel plate modes can propagate between the perfect electric conductor (PEC) ground plane and the PMC lid plate if the spacing is smaller than an effective quarter of wavelength. This provides a limited computational volume so that the computation time is significantly reduced in the case of the finite element method (FEM) or the finite difference time domain method (FDTD). By using numerical packaging with PMC lid, the ideal PMC lid has to be realized afterwards e.g. by using a lid of nails, which is a minor task as compared to existing approaches.
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| 11. |
- Larsson, Christer, et al.
(författare)
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Wideband Measurements of the Forward RCS and the Extinction Cross Section
- 2013
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Ingår i: Applied Computational Electromagnetics Society Journal. - 1054-4887. ; 28:12, s. 1145-1152
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the development of a method based on measurements of the radar cross section (RCS) amplitude and phase in the forward direction to determine the extinction cross section for the 2.5 GHz - 38 GHz frequency range using the optical theorem. Forward RCS measurements are technically complicated due to that the direct signal has to be subtracted from the total signal at the receiving antenna in order to extract the forward RCS. The efficiency of this subtraction as a function of time is evaluated. A traditional calibration method using a calibration target and a second method that does not require a calibration target are investigated and compared. The accuracy of the forward RCS measurements is determined using small spheres of different sizes. The spheres have a forward RCS that is straight forward to calculate with good accuracy. The method is also extended to polarimetric measurements on a small helix that are compared with method-of-moments calculations to validate the method.
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| 12. |
- Persson, Patrik
(författare)
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Modeling Conformal array antennas of various shapes using Uniform Theory of Diffraction (UTD)
- 2006
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Ingår i: Applied Computational Electromagnetics Society Journal. - 1054-4887. ; 21:3, s. 305-317
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Tidskriftsartikel (refereegranskat)abstract
- Traditionally, antennas have been designed as separate components, mounted on e.g. masts, buildings, and vehicles. Modem systems, however, require antennas to be integrated with existing structures. This paper discusses the analysis of conformally integrated array antennas using the hybrid UTD-MoM method, in particular arrays on doubly curved surfaces. Computed results are shown including singly and doubly curved surfaces. Most of the results are verified by measured results and calculated results obtained with a modal solution.
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| 13. |
- Tao, Yonghui, et al.
(författare)
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Design of Planar Directional Coupler using 2-Bit Fragment Structures
- 2021
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Ingår i: Applied Computational Electromagnetics Society Journal. - 1054-4887. ; 36:12, s. 1610-1615
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Tidskriftsartikel (refereegranskat)abstract
- Automatic design of planar directional coupler can be implemented by multi-objective optimization searching for the optimal planar fragment-type structure (FTS). The 2-bit FTS description scheme may include necessary fine structures in fragments to enhance the FTS design. By coding the coupler design space on PCB in 2-bit FTS, defining the FTS design matrix, and searching for the optimal structure, directional coupler can be designed without any structure presetting or artificial intervention. The scheme is demonstrated by designing 10-dB wideband directional coupler with 2-bit FTS scheme. The designed directional couplers are fabricated and tested to show maximum directivity of 58 dB with 36% operation bandwidth.
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