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In this paper, a novel design for a 5G base station (BS) antenna is proposed. The proposed antenna consists of two orthogonally polarized antennas. The two antennas are modified compact Vivaldi antennas operating in the two recommended 5G operating bands; 28 and 38 GHz with measured impedance bandwidth of 26.5–40 GHz. The orthogonality of the two antennas allows the use of two antennas on the same substrate within one enclosure to serve two sectors separately. So, instead of using two enclosures to serve two sectors, only one enclosure is required. The two elements may be part of two separate MIMO distributions. To minimize the isolation between the MIMO antennas elements with low complexity and low cost, the antenna elements have been distributed along the z-direction with half-wavelength spacing between elements including Electromagnetic band-gap (EBG) structure in between them. The simulation results have been shown that the measured mutual coupling between the array elements is improved from − 32 to − 45 dB at 28 GHz and from − 22 to − 59 at 38 GHz. The envelope correlation coefficient (ECC) is enhanced and the diversity gain (DG) is improved simultaneously. The suggested structure has been designed on CST Microwave Studio 2019. The two orthogonal antennas’ overall size approaches 34 mm × 55.8 mm × 0.203 mm3. The measured gain of the suggested design is enhanced from 10.4 to 12.8 dB at 28 GHz whereas a minor change is noticed at 38 GHz. The maximum simulated radiation efficiency approaches 96%. The antenna is fabricated and tested where good experimental results are noticed compared to the simulation results.

In the past decade, the majority of the launched satellites have a weight exceeds 1 Ton. Its development takes a long time, high cost, and has a large risk of failure, and does not allow for testing new technologies to avoid the mission’s failure. From these points of view, space-tested technologies were preferred to mitigate the risk of failure. Our goal is to build and test our own S-band communication subsystem for CubeSat. The system should be developed with reliable and compact hardware and flexible and efficient software. It consists of passive components such as the antennas and the filters and other active components. The passive components are designed, fabricated and measured while the active components are based on commercial components. In this paper, two antenna boards are designed; one board faces the earth and the other board lies on the opposite side. Each board has two antennas; transmitter and receiver antennas. The transmitter/receiver antennas are operating in the downlink /uplink at frequency bands from 2.2 GHz to 2.29 GHz and from 2.025 GHz to 2.11 GHz, respectively. This configuration keeps the communication between the CubeSat and the ground station to facilitate the de-tumbling process of the CubeSat. The second component is the filters that separate the transmitter from the receiver. The two filters have high roll off and narrow fractional bandwidth within a compact area. The transceiver system is based on the analog devices chip AD9361 controlled by zynq-7000 FPGA. The output RF signal is amplified to approach 33dBm output power to the antenna port via QORVO chip that operates in the range from 700MHz to 2700MHz. The antennas and filters are fabricated and tested where good results are noticed so that they are ready for integrating with the whole CubeSat communication subsystem.

In cognitive radio (CR), the sensitivity of the spectrum sensing (SS) algorithms depends mainly on several factors such as the receiver sensitivity, the antenna gain, the antenna efficiency and the SS algorithm itself. Researchers depend mainly on a single antenna element and sometimes on a uniform linear antenna (ULA) arrays to increase the system sensitivity. But actually the ULA suffers from the large side lobe level which in turn reduces the antenna gain. Furthermore, the separation between elements in the ULA is almost chosen to be half wavelength at the operating frequency which results in a dense array of close elements. If this separation increases slightly in order to reduce the mutual coupling between elements, the side lobes will increase and thus the realized gain is reduced more and more and as a consequence, the SNR will be reduced also which has a direct effect on the sensitivity of the system. In this paper, a low complexity and highly efficient SS technique based on antenna arrays beamforming and the generalized likelihood ratio test (GLRT) denoted as BF/GD is introduced. The proposed beamforming approach allows the utilization of the limited number of ULA elements and their corresponding RF chains to synthesize the desired radiation patterns of larger size antenna arrays for maximum gain realization. The desired pattern is realized by optimizing the excitation coefficients and inter-element spacing of the array. Consequently, the enhancement in the realized array gain will lead to a direct increase in the received signal-to-noise ratio (SNR) which significantly improves the sensitivity and the SS capability of the CR receiver without the need for extra hardware.

In this letter, a new design for two-port transmit/receive (Tx/Rx) full-duplex microstrip patch antenna for 4G and 4G advanced communication systems is introduced. The proposed duplex antenna consists of a single gear-shaped radiating patch for bidirectional radiation. The isolation between transmit and receive ports is achieved by using a frequency space filtering technique where two omega-shaped defected ground structure (DGS)-based bandpass filters (BPFs) are created at transmit and receive ports of the antenna. The antenna achieves a compact size of $\ ({{\text{70} \times \text{70}}})\text{ mm}^\text{2}$ , high isolation larger than $ - \text{36}\;\text{dB}$ at the transmit frequency ${{f}_{t}} = \text{3.3}\;\text{GHz}$ and larger than $ - \text{45}\;\text{dB}$ at the receive frequency ${{f}_{r}} = \text{3.215}\;\text{GHz},$ and small Tx–Rx frequency space ratio ${r} = \text{0.0245}$ . Also, the proposed structure can cover the entire S-band from $\text{2}$ to $\text{4}\;\text{GHz}$ by scaling the sizes of the omega-shaped DGSs to control the resonance frequencies of the embedded BPFs before fabrication. Furthermore, the embedded BPFs have sharp cutoff characteristics, high selectivity, and channel bandwidth of about ${BW} \leq \text{790}\;\text{MHz}$ at $| {{{s}_{11}}} | = | {{{s}_{22}}} | = - \text{10}\;\text{dB}$ . The simulation and measurement results highly coincide.

In most of the crowded cities and with the vast increase of capacity-hungry applications, operators tend to use capacity enhancement techniques such as MIMO, OFDMA etc. Authors’ problem is completely different. In several rural areas, the needed capacity is very low and the single base station has a standard capacitance which is considered over sufficient with respect to the required spectrum in these rural areas. The solution to make the best use of such resources is to design a two-sector antenna with a single feed. The proposed antenna covers two areas simultaneously. Thus, the spectrum capability is distributed over two sectors that share the available frequency resources. If the total area is small enough, then the base station power will be saved to the half as well as the number of antennas also reduced to the half. Otherwise, the concept of frequency reuse can be applied with minimum base stations. Authors’ antenna is designed over FR-4 substrate with a noticeable reduction in the cost. A very good agreement between the simulated and measured results is noticed .

Collision avoidance and autonomous control of vehicles have become essential needs for providing a high-quality and safe life. This paper introduces a new generic scheme for a virtual antenna array (VAA) and its application in a train collision-avoidance system (TCAS). The proposed TCAS shall have the capability of identifying the range and angle of an object in front of a moving train and provide the required alerts. Thereby, a new virtual array distribution for both the transmitting and the receiving antenna arrays is introduced to get a long-range object detection and high-resolution multi-input multi-output (MIMO) system. This can be accomplished because the VAA radiation pattern is the multiplication of the radiation patterns for both the transmitting and receiving antenna arrays, which is different than each one of them alone. In this work, the VAA is utilized in radar systems in which the radar range depends on the multiplication of the gain of the transmitting and receiving antennas. So, we introduce a new scheme for the general design of VAA-based radars. A prototype for the antenna system was fixed on a of Texas Instruments platform for the cascading radar. One of the main problems of the VAA is the loss of radiated power in undesired directions, which affects the maximum detection range in beamforming systems and degrades the diversity gain in MIMO applications. These issues have been solved by the introduction of the practical implementation of a proposed high-gain, low side lobe level VAA system for automotive radar that is based on the integration of four AWR1243 RF chips operating in a frequency range of 76 GHz to 81 GHz. It was implemented using low-power 45 nm (TI) RFCMOS technology. The measured gain of the realized VAA was 47.2 dBi, which was 1.815 times higher than that of the Texas instrumentation linear frequency modulated continuous wave (TI’ LFMCW) radar, which was 26 dBi. The proposed VAA saved 45% of the required implementation area compared to the TI’ LFMCW antenna array. The VAA system was fabricated and tested in an anechoic chamber, and it was found that the simulated and measured patterns of the proposed VAA were highly matched in terms of half-power beamwidth and side lobe level.

This paper introduces a novel MIMO UWB antenna with dual notches. The proposedantenna is based on Quasi Self Complementary (QSC) method to give wide impedance bandwidthfrom 2.4GHz to more than 12 GHz. The proposed antenna consists of a semi-elliptical patch that isfed by a tapered microstrip line. The antenna is designed on an FR-4 substrate with compact size20mm × 15mm × 1.5mm. The dual notched bands are achieved by using a square ring printed on thebottom of the substrate to reject WiMAX at 3.6 GHz. Also, a C-shaped slot is etched in the radiatingpatch to reject interference with the WLAN band at 5.8 GHz. In the proposed MIMO antenna, theisolation reduction is achieved utilizing diversity technique to minimize the mutual coupling betweenthe antennas. The isolation between MIMO elements is more than 20 dB. The envelope correlationcoefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), furthermore, channelcapacity loss (CCL) are measured and calculated. The proposed antenna is designed, simulated, andmeasured. A good agreement is shown between the experimental and simulated results.

This paper introduces a novel antenna array synthesis for radar systems based on the concept of a virtual antenna array (VAA) and the method of moments/genetic algorithm (MoM/GA) synthesis method. The VAA concept is applied to both scanning and fixed radiation pattern arrays. The proposed VAA is introduced to simultaneously support the medium-range radar (MRR) and the long-range radar (LRR) with beam width &plusmn, 7&deg, for LRR and &plusmn, 37&deg, for MRR. The proposed VAA is distinguished by its minimum number of antenna elements, simple feeding network, high efficiency, and gain, but all of these are at the expense of a large aperture antenna size compared to the planar antenna array (PAA). The VAA has the ability to have the feeding network and the radiating elements on the same layer, as compared to the multilayer PAA. The newly proposed concept is analyzed and verified analytically and experimentally. Two orthogonal (16 elements) VAAs are designed to operate in the frequency range from 23.55 to 24.7 GHz and to support a flat-shoulder shape (FSS) radiation pattern for LRR/MRR. The antenna was fabricated and tested experimentally, and good agreements between the simulated and measured results were noticed. The proposed VAA is introduced to solve the problems of large size, low isolations, low efficiency, feeding network, low resolution, and small coverage range for the antenna arrays of automotive radars. The proposed antenna array is introduced for automotive radar applications at 24 GHz.

Recently, the implementation of a complete RF transceiver system at the mm-wave band is of main interest as the recent technological trend is to build a complete system on chip (SOC). One of the main keys of the transceiver systems is the voltage-controlled oscillator (VCO) which is considered the main building block of the phase locked loop (PLL) frequency synthesizer. Realizing VCO with wider tuning range (TR) and low phase noise at the mm-wave frequency range is considered a challenging task. In this work, a cross coupled differential pair Class-C voltage controlled oscillator is employed to improve the phase noise across wider tuning range. The proposed design is based on the 0.13 µm SiGe BiCMOS process technology. A new varactor circuit is proposed to extend the tuning range. In order to extend the tuning range of the VCO more and more, a bank of fixed capacitors is added to the LC tank with a controlled MOS switches. Multiple tuning ranges are achieved using the proposed LC tank. The EM effects of the paths and interconnections through the layout are taken into considerations before fabrication. The proposed LC VCO achieved maximum post-layout phase noise of −97 (dBc/Hz) at 1 MHz offset from the carries. In addition, it achieves a wide tuning range between 18.2 GHz to 26 GHz. Moreover, the proposed VCO consumes only 12 mW from 1.2 voltage supply.

In this paper, a novel algorithm is presented for moving vehicles detection using 77 GHz automotive radars. Unlike previous methods, that use FFT estimators with CFAR based threshold detection to detect moving and fixed targets, we use the CFAR method combined with an adjustable coefficient based on the FFT algorithm output moments. It is found that, low false alarm rates are achieved using the proposed method. Furthermore, the proposed method is insensitive to the data window size in time domain as well as its low complexity relative to other methods.

Introducing new inexpensive materials for supercapacitors application with high energy density and stability, is the current research challenge. In this work, Silver doped carbon xerogels have been synthesized via a simple sol-gel method. The silver doped carbon xerogels are further surface functionalized with different loadings of nickel cobaltite (1 wt.%, 5 wt.%, and 10 wt.%) using a facile impregnation process. The morphology and textural properties of the obtained composites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen physisorption analysis. The silver doped carbon xerogels display a higher surface area and larger mesopore volume compared to the un-doped carbon xerogels and hierarchically porous structure is obtained for all materials. The hybrid composites have been utilized as electrode materials for symmetric supercapacitors in 6 M KOH electrolyte. Among all the hybrid composites, silver doped carbon xerogel functionalized with 1 wt.% nickel cobaltite (NiCo1/Ag-CX) shows the best supercapacitor performance: high specific capacitance (368 F g&minus, 1 at 0.1 A g&minus, 1), low equivalent series resistance (1.9 &Omega, ), high rate capability (99% capacitance retention after 2000 cycles at 1 A g&minus, 1), and high energy and power densities (50 Wh/Kg, 200 W/Kg at 0.1 A g&minus, 1). It is found that the specific capacitance does not only depend on surface area, but also on others factors such as particle size, uniform particle distribution, micro-mesoporous structure, which contribute to abundant active sites and fast charge, and ion transfer rates between the electrolyte and the active sites.

A novel compact RFID tag employing open stubs multi-resonators in conjunction with two fractal microstrip antennas is presented. The compact size stems from the design of multi-resonators and two orthogonal fractal antennas. The fractal shape of the antenna opens the band to operate in the UWB range from 3 to 6.2 GHz. The multi-resonators represent an encoded data where the presence of the resonance represent a 0 while the absence of it represents 1. The proposed design is a 12 bit data encoded tag. The number of bits can be increased by increasing the number of resonators but on the expense of both the geometric area and the used spectrum. The resonators are $100\ \Omega$ quarter wavelength microstrip lines branched from a $40\ \Omega$ wide line. The $40\ \Omega$ and $100\ \Omega$ lines are chosen iteratively to get the narrowest resonance band width which approaches 8% fractional bandwidth. The two tag antennas are orthogonal to each other in order to separate between the transmitted and received signals. By comparing the proposed tag with the Radar Cross Section, RCS, based tags, the proposed tag has greater RCS with a gain twice the gain of the tag antennas. The proposed tag has 12 dB signal strength compared to the RCS based tags.

With the vast spread of the RFID applications in most field of life's, most researchers pays more attention to the most cheap but challenging technology in the RFID which is the chipless RFID. The challenges in such a technology stems from the need for a reader antenna that achieve an UWB operation, circular polarization, flat gain and a compact size. This is suitable for tags of either linear or circular orientations. This paper discusses the design, the simulation and the measurement of a quadrifilar spiral antenna with four-arms and six-turns that suits the RFID reader specifications. The antenna is fabricated over FR4 material of thickness 1.6 mm using the photolithographic process. The antenna arms are printed on one side of the substrate while the feeding coaxial connector is mounted on the other side without any ground planes. The radiation pattern and the polarization are controlled by adjusting the phase shift between the four arms. The four arms allow a total length less than the longest wavelength, so the antenna size is miniaturized to large extent. The fabricated antenna has a compact size, a high gain and an ultra-wide band (UWB) radiation as well as circularly polarized (CP) radiation. The antenna has wide bandwidth compared to the antennas in literatures. The antenna operates in the range from 1.2 GHz to 12.4 GHz. By comparing the simulated and the experimental results a very promising coincidence is noticed.

This paper presents a novel security system for identifying original antiquates from the false ones in the Egyptian museums. Egypt has more than one third of the ancient antiquates in the world so the need for securing such a wealth is considered a national demand. The system depends on transmitting a wide band incident wave on the statue under investigation and by capturing the backscattered signal, an identification algorithm is applied. The system consists of two ultra-wide band horn antennas connected to two ports of a vector network analyzer where the object and the two antennas are surrounded by absorbing materials. One port is used as a transmitter while the other is used as a receiver. The E-pulse technique is applied for the discrimination between the original and the false antiquates. The E-pulse technique is based on the fact that the late time back scattered signal can be analyzed into a summation of damped sinusoids which is called the natural modes of the object. The E-pulse technique is a technique that extracts an identifying signal called an E-pulse from the late time response. The convolution of such a pulse with the back scattered signal from the original signal results in a null result after the early time is elapsed. The convolution with the backscattered signal from other objects reveals none zero level in the late time. The identification is done laboratory over gold coated statues in the Egyptian museum. Good identification between different statues is noticed experimentally.

A Vivaldi antenna with three techniques to enhance the radiation properties is introduced. The first technique is the insertion of an elliptical patch parasitic radiating element in the Vivaldi aperture to enhance the coupling between arms and to produce strong radiation in the end fire direction. The second technique is the addition of corrugation at the antenna edge to improve the antenna characteristics. The third technique is insertion of planar reflector at the backend of the antenna that enhance the front-to-back (F/B) ratio to a great extent. The antenna is designed using standard 0.18 μm six metal layer CMOS technology. The overall size of the antenna on chip (AOC) is 500 umx870 um. The proposed antenna reveals end-fire radiation pattern with 0.7 dBi simulated average gain and 37% simulated radiation efficiency

This paper introduces an antenna for Automotive Radar to operate at 77 GHz. The proposed antenna consists of a hybrid radiator and dielectric resonator. The hybrid radiator is a circular patch that feed by aperture method and the dielectric resonator is ring that feed by the circular patch to operate at 77 GHz with high gain 12 dB for one element. The EBG structure is implemented on the top layer to widens the proposed band, gives high gain and to reduce surface waves. The compact size of one element 3.5mm×3.5mm×l.16mm to operate from 75.3 GHz to 80 GHz with gain 12.3 dB.

This article presents a comprehensive study on the performance of a compact multiband antenna operating in LTE700, GSM850, GSM 900, DCS1800, PCS 1900, UMTS 2100, most of LTE bands (especially the low-frequency LTE 700 band), and wireless applications. The antenna consists of a monopole in conjunction with meander line antenna. An EBG structure is used to miniaturize the antenna size and to enhance the gain in the direction away from the antenna to lower the SAR within the human body. The EBG structure also contributes in open the operating bands. The proposed antenna is tested using the four recommended test positions of the CTIA association where the proposed antenna reveals good performance in all test cases. Return loss, radiation patterns, SAR, and efficiency of this antenna are computed in free space, in the presence of handset (keypad, battery, speaker camera, RF circuit, and LCD) in talking position, in standby position, in packaging, and as well as in the presence of head and hand in free space and in a car. The SAR values are taken into account not to exceed the standard safety levels. In addition, radiation efficiencies of these handset antennas are computed in the presence of head and hand. All simulation results are performed using the CST software. Simulation results are in good agreement with the measurement results.

The most common chipless RFID tags depends on the existence of a set of resonators inserted between two orthogonal antennas in order to increase the response of the reader system. In this paper, an orientation independent tag without the two antennas but with a high response is proposed. The tag design is based on etching circular slots on one layer of a substrate without ground. The symmetry of the tag is the reason behind the orientation independent response. The circular set of resonators are repeated in different space distribution to increase the back scattered signal of the tag in order to reach the response of the two antennas of the conventional chipless tags. The proposed tag reveals high frequency response, compact size and at the same time orientation independent compared to other chipless RFID tags. The proposed tags are suitable for banknotes, credit card applications and similar applications.

With the rapid increase in wireless applications such as mobile base stations, radars, etc., the antenna array becomes the key issue in solving these problems. Since the synthesis of the radiation pattern from beamwidth and SLL points of view depends mainly on the feeding network. Most goals are achieved via the excitation coefficients optimizations. This may make the feeding network more complicated since the unequal power dividers utilized in beamforming almost has large dynamic range ratio. In this paper, the optimization is performed on the spacing between elements using the known neural network algorithm. The optimization goals are the HPBW to be 7o and the SLL to be −20 dB. The feeding network is implemented using the Wilkinson power dividers and the phase compensation is done using additional sections of meandered transmission lines. Excellent agreement is obtained between the simulated and experimental results.

In this paper, A Quasi Yagi antenna with enhancement in the radiation properties and size reduction is introduced. The antenna is designed using standard 0.18 µm six metal-layer CMOS technology. The proposed antenna consists of a T-shaped meandered line operates as a driven dipole element connected to a Coplanar Wave Guide (CPW) through a Coplanar Slot (CPS) line transition. A meandered parasitic strip on front of the driver operates as a director and a planar arc is used as a reflector to reduce the back radiation. The overall size of antenna on chip (AOC) is 720 µm×850 µm. The proposed antenna reveals an end-fire radiation pattern with 0.3 dBi simulated average gain and 38% simulated radiation efficiency.

In this paper, a new configuration of dual-band, dual-polarized microstrip antenna applicable to mobile base stations is proposed. The concept behind the new design is the use of an artificial magnetic conductor (AMC) structure that operates in the required two bands beneath a radiating diamond shaped slot. The choice of the diamond-shaped slot is due to its support of an infinite number of resonant modes where the dimensions of the diamond shape have more degree of freedom that controls the excited modes when compared to the rectangular slot. The proposed antenna works over the 870–960 MHz (GSM850/GSM900) band and the 1710–2170 MHz (DCS1800/PCS1900/UMTS2100) bands for mobile communication systems. The antenna is suitable for transmitting and receiving mobile signals since it has two ports of orthogonal polarization. The antenna is fabricated on a combination of FR4 dielectric substrate and foam layers in order to achieve low cost. The proposed antenna yields high isolation between its two ports not exceeding −30 dB and a front-to-back ratio exceeding 15 dB. The average antenna gains are about 6.6 dBi at the GSM850/GSM900, 7.1 dBi at the DCS1800/PCS1900, and 6.8 dBi at the UMTS2100 bands. The theory of radiation is proved analytically and verified by comparing its results with some simulated results. Finally, a good agreement between the simulated and measured results is noticed.

With the vast emergence of new mobile applications, multiband operation in a compact size is mandatory for market penetration. In this paper, a new mobile handset antenna suitable for both mobile and wireless LAN services is presented. The antenna operates for most of the mobile applications such as the GSM 900, DCS 1800, PCS 1900, UMTS 2100, and most of the LTE bands, especially the low frequency LTE 700 band at �10 dB. The antenna also supports the WIMAX, WLAN, and the ISM bands. The antenna not only has a compact size, but also supports a low SAR radiation at all the operating frequencies. The antenna consists of two concentric open rings that act as quarter wavelength monopoles. The inner ring radiates at 900 MHz, while the outer ring radiates at 700 MHz. The inner ring works as a monopole radiator as well as a slot radiator fed by another rectangular monopole. The advantage of the slot is that it supports a wide range of modes that by its role open the radiation band from 1.65 to 3.6 GHz. The antenna meets three challenging parameters: compact size, multiband operation including low frequency bands, and low SAR radiation. Good agreement is noticed between the experimental and simulated results.

Recently, the mobile handsets support both the mobile and wireless LAN services. Thus, our target is to introduce a new antenna that supports both services. The antenna operates for most of the mobile applications such as the GSM 850, GSM 900, DCS 1800, PCS 1900, UMTS 2100, and most of the LTE bands, especially the low-frequency LTE 700 band. The antenna also supports the WiMAX, wireless local area network (WLAN), and the Industrial, Scientific, and Medical (ISM) bands. The antenna not only has a compact size, but also it supports a low specific absorption rate (SAR) radiation at all the operating frequencies. It consists of a monopole, a meander line, and an electromagnetic band-gap (EBG) structure. In order to cover the low frequency bands, a meander line is utilized due to its compact size, but unfortunately it is a narrowband antenna that is difficult to cover both LTE700 and GSM 900 bands. The solution stems from the use of an EBG structure that widens the band to cover the two low frequency bands and to reduce the maximum SAR. The higher frequency bands are supported by both the monopole and the meander line since they acts as traveling-wave antennas at the high frequency bands. The antenna meets three challenging parameters: the compact size, the multiband operation including the low frequency bands, and the low SAR radiation. Good agreement is found between the experimental and the simulated results.

Synthesis of arbitrarily shaped radiation patterns using linear antenna arrays has a significant importance in many applications. Many attempts based on analytical schemes are exerted for this purpose. However, these analytical methods are developed for specific problems, and usually synthesis of the radiation pattern is subject to only one restriction. On the other hand, optimization algorithms are utilized for more general problems. However, these algorithms require more computational time. In this letter, a new hybrid technique for synthesizing arbitrary-shaped radiation pattern using a linear array is developed. The algorithm is based on a combination between the method of moments (MoM) and the genetic algorithm (GA). The proposed algorithm is applied to synthesis of both symmetric and asymmetric radiation pattern distributions with minimum number of elements. Excellent agreement is obtained by comparison to other analytical and optimization techniques.

In this paper, a multi-band microstrip slot antenna is presented. The antenna is suitable for operation in mobile phone base stations. The antenna operating bands are (0.824 - 0.894) GHz, and (1.83 - 2.2) GHz. The antenna supports GSM850, PCS1900, and UMTS2100. The antenna is based upon placing a metallic rectangular brick inside a rectangular etched slot on the ground plane and incorporates a simple single layered feeding technique to achieve dual band operation used in mobile communications. This antenna element may be used in a linear antenna array to act as a mobile base station transmitter. The effort was directed towards the design of a single standalone antenna; however, the complete performance would be evaluated when it is incorporated as an array element. The average gain is 5.3 dBi at the lower band (GSM850), and is 2.5 dBi at upper band (PCS1900/UMTS2100). The Front-to- back ratio (FBR) is 16.38 dB at the lower band and is greater than 19.3 dB, at the higher band.

Free 60 GHz radios have unique characteristics that make them significantly different from traditional 2.4GHz or 5GHz license-free radios and from licensed-band millimeter-wave radios. These characteristics make 60 GHz radios more attractive for wireless systems. In this paper, dipole like Vivaldi antenna is designed to meet the requirements of 60GHz band. The feeding circuit is 100 Ω differential feeding. The operating bands range is (54GHz to 70GHz). The radiation patterns, efficiency, reflection coefficients (S 11 ), directivity and radiation gain are illustrated. The design is fabricated using one substrate of quartz glass. The antenna size is 2.225×0.3276×0.675 mm 3 .

Simple multiband planar antenna for wireless communication applications is presented. The proposed antenna performs four resonant modes covering multibands of wireless standards, including LTE 700, GSM, DCS, PCS, UMTS, and LTE 2300/2500. Furthermore, it covers the ISM, WiMAX, and the WLAN bands. The geometry of the proposed antenna consists of a single FR4 substrate where an open cavity fed by a coplanar U-shaped monopole is etched on one side and a short-circuited meander line in the opposite side. The cavity by its nature supports a wide range of higher frequencies, while its boundary that consists of a thin monopole resonates at 900 MHz. The meander line in the opposite side supports the LTE 700 band. The operating bands ranges are (680–748 MHz), (870–960 MHZ), (1.36–1.59 GHz), and (1.71–2.56 GHz). The antenna size is 30 × 18 × 0.8 mm3. The antenna not only has a compact size but also supports a low SAR radiation at all the operating frequencies. The proposed antenna is tested using the four recommended test positions of the CTIA association where the proposed antenna reveals good performance in all test cases in the presence of handset (keypad, battery, speaker camera, RF circuit, and LCD) in talking position, and in standby position.

The One of the most challenging problems that encounter the Egyptian society is the lack of significant health care in the rural areas. This problem leads to more severe problems that face the society; the patients from the different rural areas needs to travel to the Egyptian capital where the most experienced physicians are available. This will make overhead not only on the patient budget but on the country budget since the focus on the capital makes a severe traffic problem which threaten most of the economic sectors. The telemedicine is considered one of the most important solutions that could mitigate the accumulated problems of lack of experienced physicians in the Egyptian rural areas. The application of the telemedicine encounters several challenges in Egypt; the lack in the experience in dealing with the telemedicine in these areas and the problem of insufficient medical experts that could fulfil the gab. In this paper, a new ICT-based telemedicine system is proposed to serve the Egyptian society. The portal is already released and snapshots are included

This paper proposes a new mobile handset antenna structure with compact size and multibands to reduce the value of the specific absorption rate (SAR). The antenna is based on a monopole and a meander line structure that operates at the dual-bands from (587-977 MHz) and (1.67-8.63 GHz) to cover most of the mobile operating bands and other wireless applications. The covered bands are the GSM 900, DCS 1800, PCS 1900, UMTS 2100, and most of the LTE bands. Furthermore, it covers the ISM, WiMAX and the WLAN bands. In addition, an electromagnetic band gap (EBG) structure is embedded on the bottom layer of the substrate to reduce SAR. The EBG structure which has band gap capability and acts as AMC surfaces can reduce the surface waves and prevent the undesired radiation from the antenna. Thus, the EBG structure can reduce the electromagnetic fields toward the human head direction. The antenna volume is 27×25×0.8 mm3 (0.54 cm3), so the proposed antenna is suitable for many wireless handheld devices. The simulation results are compared to the experimental measurements where a good agreement is observed.

In this paper, a multi-band dual-polarized transceiver microstrip slot antenna with dual feed is presented. The antenna is suitable for operation in mobile phone base stations. The antenna operating bands are (0.792 – 0.979) GHz, (1.74 – 2.2) GHz and (2.4 – 2.68) GHz. The antenna support GSM, DCS, PCS, UMTS, ISM and LTE. The proposed antenna shows good reduction in area and height by 37.46% and 92.78%, respectively compared to other one's with an isolation more than 29 dB between ports. The antenna is based upon two orthogonal cross slots etched on the metallic ground plane and incorporates a simple single layered feeding technique to achieve dual polarization radiation with an isolation more than 29 dB between them. The effort was directed towards the design of a single standalone antenna; however, the performance would be better when it is incorporated as an array element. Also, the experimental results are compared to the simulated results. Very good results are obtained.

Shift-Operator Finite difference Time Domain (SO-FDTD) method is presented as a new efficient technique for simulating electromagnetic wave interaction with different types of dispersive media like ferrite material, chiral media and left-hand metamaterials. The main idea of this method is to formulate the problem in frequency domain and to present the dispersive relations between the fields inside the medium as polynomials of jω. These polynomials are converted to time domain by replacing jω by the time derivative operator. Then this time derivative operator is converted to the corresponding time shift operator which is used directly to obtain the corresponding update equations of electric and magnetic field components. The resulting update equations do not require time convolution or additional vector components. The present analysis does not require also any transformation. Significant improvement is obtained in memory requirements by using this method while the computational time is nearly the same compared with other similar techniques like Z-transformation FDTD.

In all radar detection systems, the antenna system has resolution that is inversely proportional to the antenna beam-width. Even with a very narrow beam-width, the resolution decreases with the increase in the target height. The resolution is defined by the capability to discriminate between targets. In this paper, we propose the target identification scheme, the Extinction pulse “E-pulse”, to discriminate between two targets that lie within the antenna main beam. In this paper, the discrimination procedure is tested using two adjacent cylinders illuminated by an incident plane wave with arbitrary incidence angle. The scattered field is calculated using the XFDTD software package.

This paper presents a scattered field formulation for the finite difference time domain technique applied to dispersive media characterized by the Debye equation with two relaxation constants. The 3D formulation is based on the auxiliary differential equation (ADE) approach. For verification purposes, numerical results for a one dimensional problem involving reflections from a dispersive dielectric half-space are presented and compared with the exact solution.