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Title: ACES Journal February 2013
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 6948 KB

Title: ACES Journal February 2013 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 632 KB

Title: Selecting Sampling Interval in the Improved Spectral Domain Method to Simulate Microstrip Circuits
Abstract: In this paper, we investigate the spectral method that calculates the S-parameters for microstrip circuits and antennas. A sampling interval selection criterion is proposed. The scheme for low-loss cases is specially discussed. Several examples are employed to demonstrate the engineering applications of the spectral domain method and its results are compared with previously published and measured results.
Author(s): Z. Gong, R. Mittra, W. Yu, X. Yang, J. Guo
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 311 KB

Title: A Closed-Form Spatial Greenís Function for the Thick Microstrip Substrate: The Meshless Interpolation Approach
Abstract: n this paper the Greenís functions (GFs) of a thick microstrip in the spatial-domain is computed based on expanding the corresponding spectral-domain functions over inverse quadric (IQ) radial basis functions (RBFs). The scattered data interpolation ability of RBFs is exploited for efficient sampling of the Sommerfeld integration path (SIP), passing from close vicinity of singularities in the complex k? plane. By this, the information content of spectral-domain GFs is preserved, which makes it possible to compute the far-fields accurately. Thus, the method can be applied to the analysis of electrically large structures near layered media. The proposed method is direct with only one approximation level.
Author(s): B. Honarbakhsh, A. Tavakoli
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 430 KB

Title: Analysis of Thick Microstrip Antennas by the Meshfree Collocation Method
Abstract: A meshless integration free approach is applied to numerical solution of the mixed potential integral equation (MPIE) governing various microstrip resonators/antennas. The idea behind the discrete complex image method (DCIM) is exploited to provide closed form expressions for all of the integrals, leading to an efficient spectral-domain meshless integral equation (IE) solver. The proposed meshfree method (MFM) is compared with low order method of moments (MoM) from the aspects of memory usage and simulation time, which shows superior performance of the MFM.
Author(s): B. Honarbakhsh, A. Tavakoli
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 816 KB

Title: A Method to Reduce the Back Radiation of the Folded PIFA Antenna with Finite Ground
Abstract: A novel method, named the resistors and inductors loading, is proposed in this paper to reduce the back radiation of the folded PIFA antenna with finite ground. With different loading schemes (i.e., resistors loading, inductors loading, and resistors and inductors loading), variable reduced back radiation and gain can be achieved. However, there is a compromise between the gain and back radiation and it can be chosen based on the specified applications. A prototype with resistors loading is fabricated and measured to verify the proposed design. Measured results agree well with the simulated results.
Author(s): Y. Li, P. Yang, F. Yang, S. He
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 747 KB

Title: Low-Profile Broadband Top-Loaded Triangular Antenna with Folded Rim
Abstract: This paper presents the impedance matching technique and the bandwidth characteristics of a low-profile top-loaded triangular antenna with oblique shorting pins. The folded rim is arranged at the edge of the finite ground plane. The bandwidth diagrams for various antenna heights, finite sizes of the ground plane, and the widths of the folded rim are obtained through the moment-method simulation. The maximum bandwidth of 43 % is achieved with 0.05 ? height. For the low-profile configuration, the bandwidth of 17 % is obtained with 0.03 ? height.
Author(s): N. Michishita, W. J. Kim, Y. Yamada
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 991 KB

Title: UWB Square Monopole Antenna with Omni-Directional Radiation Patterns for Use in Circular Cylindrical Microwave Imaging Systems
Abstract: In this paper, a novel ultra-wideband printed monopole antenna (PMA) for the use in a circular cylindrical microwave imaging system is presented. The proposed antenna consists of a square radiating patch and a ground plane with a pair of L-shaped slots and two L-shaped conductor back plane, which provides a wide usable fractional bandwidth of more than 130 % (3.02 GHz - 15.21 GHz). By cutting two modified Lshaped slots with variable dimensions on the ground plane corners and also by inserting two Lshaped conductor back plane on the other side of the substrate, additional resonances are excited and hence much wider impedance bandwidth can be produced, especially at the higher band. The proposed antenna has an ordinary square radiating patch, therefore displays a good omni-directional radiation pattern even at higher frequencies, and also its radiation efficiency is greater than 82% across the entire radiating band. The designed antenna has a small size of 12 ◊ 18 mm2. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for circular cylindrical microwave imaging system.
Author(s): N. Ojaroudi, M. Ojaroudi, N. Ghadimi, M. Mehranpour
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 542 KB

Title: A Compact Ultra-Wideband Antenna with Improved Triple Band-Notched Characteristics
Abstract: In order to prevent interference problem due to existing nearby communication systems within the ultra-wideband (UWB) operating frequency, a compact CPW fed triple-band-notched antenna using modified co-directional complementary split ring resonators (CSRRs) is proposed and investigated. The proposed antenna is realized by etching three modified co-directional CSRRs with different centers in the radiating patch. The measurement result shows that the proposed antenna can guarantee a wide bandwidth from 2 GHz to 16 GHz (VSWR? 2) with triple unwanted band-notches successfully. The proposed antenna occupies a compact area of 25 ◊ 27.9 mm2 only. The antenna demonstrates omni-directional radiation patterns across almost the whole operating bandwidth, which is useful for UWB (3.1 GHz - 10.6 GHz) applications.
Author(s): D. Jiang, Y. Xu, R. Xu, W. Lin
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 1422 KB

Title: Band-Notched Split-Ring Resonators Loaded Monopole Antenna for Ultrawideband Applications
Abstract: A compact printed ultrawideband (UWB) monopole antenna with triple bandnotched characteristics is presented. By adding a Split-Ring Resonator (SRR) on the radiating patch, the notched band in 3.3 GHz - 3.7 GHz for the WIMAX system is achieved. Furthermore, the proposed approach that utilizes the folded rectangular SRR structure is proven to be an effective way for band-notched designs. The antenna exhibit good band stop characteristics to reject the WLAN bands (5.15 GHz - 5.825 GHz bands) and downlink of X-band satellite communication systems (7.25 GHz - 7.75 GHz bands). The VSWR, gain, and radiation patterns of the proposed antenna are presented, which prove that the designed antenna is a good candidate for various UWB applications.
Author(s): J. Zhang, H. Yang, H. Liang
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 851 KB

Title: A Novel Bandpass Filters Using Complementary Split Ring Resonator Loaded Half Mode Substrate Integrated Waveguide
Abstract: A half mode substrate integrated waveguide with hexagon shaped complementary split-ring resonators (CSRRs) etched on the top of the waveguide is presented in this paper. The simulated results show that extra low insertion loss of about -0.1 dB and the return loss of -10 dB can be achieved. The proposed structure allows the implementation of a forward wave below the characteristic cutoff frequency of the waveguide. By changing the radius of the hexagon shaped CSRR, which is incorporated on top of the waveguide, the pass frequency band can be tuned easily. Finally, a compact band pass filter is fabricated and validated.
Author(s): D. Jiang, Y. Xu, R. Xu, W. Lin
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 453 KB

Title: Design of Broadband Single Layer Printed Reflectarray Using Giuseppe Peano Fractal Ring
Abstract: In this paper, a broadband single-layer microstrip reflectarray element composed of a Giuseppe Peano fractal ring and a square ring is presented and investigated. The proposed element has been validated by comparing the simulation results with those obtained by measurement in a waveguide simulator. By using this type of cell element, a wideband single layer reflectarray is designed, fabricated, and tested. Measured results demonstrate 1 dB gain bandwidth of 17 % over the frequency range of 12.25 GHz - 14.5 GHz.
Author(s): M. Maddahali, K. Forooraghi
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 670 KB

Title: Enhanced Bandwidth Small Square Slot Antenna with Circular Polarization Characteristics for WLAN/WiMAX and C-Band Applications
Abstract: This article proposes a novel printed slot antenna with circular polarization characteristics using an L-shaped slot in the ground plane and an L-shaped radiating stub with a pair of ?-shaped slits for simultaneously satisfying wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX), and C-Band applications. The operating frequencies of the proposed antenna are 5.2/5.8 GHz, which covers WLAN system, 5.5 GHz for WiMAX system, and 4 GHz for C-Band system. The desired resonant frequencies are obtained by adjusting the length of ?-shaped slits in the both sides of tapered microstrip feed-line. The measured results show good agreement with the numerical prediction. The designed antenna has a small size of 20 ◊ 20 mm2
Author(s): M. Ojaroudi, N. Ojaroudi, N. Ghadimi
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 430 KB

Title: Eccentricity Compensation in Switched Reluctance Machines via Controlling Winding Turns/Stator Current: Theory, Modeling, and Electromagnetic Analysis
Abstract: In this paper, a new eccentricity compensation method for Switched Reluctance Machines (SRMs) is presented. In this regard, the dependency of radial force (RF) on variation of number of turns for stator coils and fault level is demonstrated analytically and principle of the new compensation strategy is introduced as well. This strategy is implemented on an SRM utilizing Finite Element Method (FEM) under different fault conditions. This approach is accomplished through switching among the various arrangements in the number of turns for the coils on the stator poles; hence, unbalanced magnetic force (UMF) is controlled without additional auxiliary coils. Simultaneously, regulating the stator currents guarantees the motor torque is not diminished. This comprehensive approach is suitable for different types and structures of SRMs and will compensate or control eccentricities in a wide range of eccentricity faults namely 10%-70% while motor performance is not impaired.
Author(s): E. Afjei, M. R. Tavakoli, H. Torkaman
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
Download Link:Click here to download PDF     File Size: 970 KB