Search

Presented in this paper is a simple, small-sized, and hook-shaped monopole antenna fed by an Asymmetric Coplanar Strip (ACS) for different dual-band operations. The antenna operates at 3.5 and 5.2 GHz; hence, serving WiMAX and WLAN applications. Dual resonances were attained by integrating a quarter-wavelength strip with a C-shaped half-wavelength loop strip. The proposed antenna footprint is 20 × 7.9 mm2. Based on the achieved outcomes and the antenna compactness, it can be highly nominated for use in 3.5/5 GHz wireless communications applications and wireless gadgets. [ABSTRACT FROM AUTHOR]

This paper presents a new diplexer design of a new-coupled composite right/left-handed (CRLH) resonator to serve the LTE applications. The realization of the diplexer is designed as coupled two zeroth order π-CRLH resonators to represent with zero electrical length and hence attaining a significant size reduction. The filters are designed to achieve a desired frequency bandwidth of 4% ∼16.7 Q-factor and ∼0.066 coupling coefficient at a centre frequency of 2.1 and 2.6 GHz with transmission zeros. The diplexer exhibits a rejection level of 15–20 dB while maintaining insertion loss of 1 dB for the Tx and Rx bands. The circuit design concepts are verified using equivalent circuit simulations, full electromagnetic simulations and experimental measurements. In conclusion, a good agreement is perceived between the measured and simulated data with size compactness of 30 × 60 mm2. [ABSTRACT FROM AUTHOR]

In this paper, a bi-directional UWB MIMO antenna is presented and investigated for superior UWB MIMO performance. The MIMO antenna elements are proved to have a typical impedance matching and directional radiation pattern over the bandwidth 3.9–10.6 GHz. The MIMO antennas have a very low mutual coupling by using efficient DGS. The MIMO antennas are evaluated for perfect MIMO performance. Results confirm that the envelope correlation coefficient (ECC) is almost lower than 0.01 over the UWB bandwidth which guarantees independent transmission/reception through MIMO system sub-channels. Moreover, spatial diversity and spatial multiplexing are proved through better than 9.8 dB diversity gain and 90% multiplexing efficiency. All simulated results are confirmed by measurements. [ABSTRACT FROM AUTHOR]

A compact low-loss microstrip diplexer with four controllable transmission zeros (TZs), all less than 41 dB, is presented. The diplexer circuit consists of two coupled gap bandpass filters with a T-junction as a combining circuit. Channels' filters metalize SIW resonators loaded with metamaterial cells operated at zeroth order mode for compactness and low loss operation. For each channel, a fractional bandwidth of 1.9% is obtained. Also, two TZs at both sides of the resonant frequency are obtained by mixed electric and magnetic coupling between channels' resonators. Design methodology for filtering response and placing TZs at certain frequencies are discussed in detail. There is a good agreement between simulation and measurement with isolation better than 40 dB. Moreover, the diplexer has a small size of (1.1×1.43 λg2). Lower and higher TZs are located at 4.75 and 5.69 GHz, for the lower channel, and at 5.4 GHz and 6.2 GHz for the higher channel, respectively. [ABSTRACT FROM AUTHOR]

This paper proposes a new algorithm for Arabic optical font recognition (AOFR) as the first stage for Arabic optical character recognition. The proposed algorithm uses scale-invariant detector, gradient-based descriptor, and k-means clustering. The scale-invariant detector is used to find key points that identify the font of an image of printed Arabic text. The work in this paper compares between several scale-invariant detectors and selects the best one for AOFR. A gradient-based descriptor similar to the one in the famous scale-invariant feature transform algorithm is used to describe the detected key points. In addition, k-means clustering is used for font classification. In this paper, the mean recognition rate is used to evaluate the performance of the proposed algorithm. The proposed algorithm shows superior performance when compared with recently published algorithms for AOFR. [ABSTRACT FROM AUTHOR]

This article presents a compact meta-surface (MS) based antenna with dual-band operation for 5G applications. The MS-based antenna consists of a layer of MSs on the top of a single-band microstrip patch antenna. The dual-band operation is achieved by adding the MS layer at a height of 0.089λ 0 , where λ 0 is the free space wavelength at the lower resonant frequency. The patch antenna is designed on a 21 mm × 20 mm × 0.508 mm substrate. The MS is comprised of two metallic layers printed on the top and bottom of a 1.575 mm Rogers 5880 substrate. The overall thickness of the proposed antenna is 0.27λ 0. The proposed antenna is fabricated and tested. The configuration achieves dual-band features with bandwidth, and gain of 1 GHz, and 10 dBi at 26.4 GHz, 800 MHz, and 9.6 dBi at 27.6 GHz, respectively. Also, a high radiation efficiency of 91.2 % is achieved at the frequency bands. [ABSTRACT FROM AUTHOR]

In this study, a resistor-loaded wideband conformal metamaterial absorber has been designed, fabricate, and analyzed experimentally. The proposed absorber consists of lumped resistors loaded on cross-shaped resonators at the top side of the flexible substrate and copper metal film separated by flexible foam on the substrate's backside. The total thickness of the absorber is 0.07λ o , where λ o is the lowest absorption frequency. The simulated results exhibited absorption from 3.25 − 13.6 GHz (absorption bandwidth 123%). The wideband absorption mechanism of the absorber was analyzed through the equivalent circuit model and parametric study. The designed structure has been tested on the planar and curved surfaces and measured the results. The simulated and experimental results have good agreement between them. The designed absorber can be suitable for scientific and military applications as of its wideband absorption bandwidth, polarization-insensitive, and conformability. [ABSTRACT FROM AUTHOR]

• A novel model of SERS was designed using an innovative glass and nano-gold. • The proposed model can detect the circulating tumor-derived exosomes in HCC cases. • The new SERS model could identify HCC patients non-invasively with high accuracy. • The RS exosomal analysis had 95 % sensitivity and 100 % specificity for detecting HCC. The current hepatocellular carcinoma (HCC) diagnostic approaches lack adequate sensitivity and specificity. So, this study was performed to develop an innovative model of surface-enhanced Raman spectroscopy (SERS) that can detect HCC patients by identifying the circulating tumor-derived exosomes. Sixty participants, including normal controls, hepatitis C virus (HCV)-infected patients, and HCV-associated HCC patients, had their whole blood samples and exosomes separated from these samples analyzed using Raman spectroscopy (RS). A revolutionary model of SERS, based on an innovative glass and nano-gold, was designed to directly identify exosomes. Its measurements were simulated by Comsol Multiphysics (5.6). The RS examination of the whole blood samples revealed no Raman peaks. Yet, the isolated exosomes from these samples generated Raman peaks at 400 and 1000 cm−1 wavenumbers in the HCV group. A Raman shift was detected in HCC patients at 812, 852, and 878 cm−1 wavenumbers with intensity ratios of 120, 130, and 60, respectively. The RS had a sensitivity and specificity of 95 % and 100 %, respectively, for detecting HCC. However, the newly-designed SERS was able to identify the HCC-derived exosomes, at 812 and 878 cm−1 wavenumbers, with boosted intensity ratios of 9*106 and 4*106, respectively, in the whole blood samples. The newly-developed SERS model has the potential to detect HCC patients through recognizing the tumor-derived exosomes non-invasively, with high accuracy, and without the need for laborious exosomal separation. Nonetheless, bringing this technology into the clinic demands the establishment of spectral databases and their validation using the current gold standards. [ABSTRACT FROM AUTHOR]

A flexible paper based and dual-band antenna is designed for UMTS service (1.9 GHz) and WiMAX services (5.8 GHz). Flexible paper is used as a substrate for the printed antenna. Expanded graphite ink is used to enable printing the antenna on the substrate. The antenna has been designed, simulated, fabricated, and measured. Steps of preparing the conductive printed ink and fabrication of the antenna have been discussed. The conductivity of the printed antenna is measured to be 1 × 104 S/square and the thickness is also measured with an average of 30 µm. Through the whole paper, good agreement between simulated and measured results is satisfied. In addition to the achieved flexibility, the antenna has demonstrated good measurement results. First, the antenna has a bandwidth of 300 MHz at 1.9 GHz and 400 MHz at 5.8 GHz with fractional bandwidth of 15.7% and 6.8% at the both bands, respectively. Second, the measured antenna radiation pattern has indicated that it is omnidirectional at 1.9 GHz and approximately omnidirectional at 5.8 GHz. Third, The antenna gain is 1.266 dB and 0.512 dB at the two bands, respectively. Finally, the antenna's efficiency at the both bands is 35% and 55%. [ABSTRACT FROM AUTHOR]