ABSTRACT. In this study, a novel TEM horn antenna design is introduced for Ground Penetrating Radar (GPR) applications. TEM horn antennas are mostly used in GPR for the advantages of high gain and power capability and wide bandwidth. At the low frequency of the GPR applications, the antenna size must be big. However with using shorting plate with conventional TEM Horn antennas, antenna size can be reduced. A novel shorting plate structure is presented. The effect of this structure and the contributions to antenna performance is investigated. HFSS simulations and measurement results of a prototype is presented. It has been seen that they are consistent with each other

ABSTRACT. The unique configuration and application of the Active Protection System (APS) radar sensor, developed by Reutech Radar Systems, requires the development of a novel multipath interference model. This paper derives a mathematical model for the effects of specular multipath interference (primarily due to ground reflections) on the received signals of a dual-frequency phase-comparison FMCW radar. Two formulas are derived, one describes the change in amplitude and the other describes the change in phase due to specular multipath. This has interesting and previously unknown effects when Range-Doppler processing is applied to the corrupted input signal. Simulation results and measurements are presented to corroborate the theory.

ABSTRACT. in this work, an electronically beam switching device using Rotman lens for mm wave technology at 60 GHz is proposed. The antenna elements are fed by a Rotman lens with five input ports and seven output ports. Rotman lens is a very good candidate as beam forming network due to its compact and planar structure. Five different scanning angels can be accomplished by this design:-30 ˚,-15 ˚, 0 ˚, +15 ˚, and +30 ˚.The simulation results show good return loss and true time delay performance. The proposed design can be implemented as printed lens-fed multi-beam arrays.

ABSTRACT. In this paper, a sparse direction-of-arrival (DOA) estimation based on a shifted coprime array configuration is proposed. The proposed array utilizes two uniform linear arrays (ULAs), one of them is shifted from the other by certain displacement. The displacement is optimized such that the number of lags in the difference coarray is increased. Thus, the value of this displacement changes for different number of sensors. The resulting array is denoted to as shifted coprime array (SCA). Qualitative and quantitative results using Matlab reveal the strength of the proposed configuration. Compared with coprime array with displaced subarrays (CADiS), the proposed SCA has lower aperture and achieved larger number of consecutive lags.

ABSTRACT. A design of compact size and multi –band composite right-left handed meta-material antennas for wireless applications is presented. The proposed antenna consists of single left handed cell. The series interdigital capacitor and short circuit stub which acts as shunt inductor are considered the main block of the proposed antenna. The proposed antenna is designed to operate at different frequency bands. Because of the nonlinearity of the left handed region of the composite right left handed transmission line, the compactness of the antenna has been achieved. The proposed antenna has compact size (its size is only 28 X 22 mm2). The design represents size reduction of approximately 60 % compared to conventional patch antennas operating at the same frequencies. The antenna is designed, simulated and measured. A good agreement is achieved between the measured and simulated results.

ABSTRACT. This paper presents a new technique, that does not require the use of spatial smoothing, for detecting the directions of coherent signals impinging on a Uniform Circular Array (UCA). The new technique is based on transforming the original UCA into an equivalent Virtual Uniform Linear Array (VULA) upon which a Toeplitz re-construction is employed to alleviate the inaccuracies incurred in the equivalent VULA. Simulation results demonstrate the improved accuracy and higher detection capacity of the proposed technique.

ABSTRACT. This paper aims to address the millimeter wave characterization in forest environments for high data rate 5G wireless sensor applications. The excess attenuation due to foliage depth at Short-range in forest areas at expected 5G frequencies is investigated. Different foliage models are presented and are validated using the acquired values from different site measurements at expected 5G frequencies which could provide a valuable information for the high data rate WSN planners. The results shows that at 15 GHz frequency the attenuation predicted by the NZG model is closer with the acquired values with an average standard deviation of 7.2 dB and at frequencies such as 28GHz and 38 GHz FITU-R gives the best fit at both In-leaf and out-of-leaf scenarios. The average standard deviation at these frequencies is observed to be 12.74 dB and 16.45 dB. The attenuation experienced due to foliage was higher in In-leaf scenario than that of out-of–leaf at all the 5G frequencies.

ABSTRACT. In this paper, the performance of orthogonal frequency division multiplexing technique, over a measured underground mine channel at 2.4 GHz, is investigated. The effect of increasing the number of subcarriers as well as the guard interval length is considered. In a further step, the performance of the OFDM scheme when combined with multiple input multiple output system, using, the well-known, diversity technique, space time block coding (STBC), is provided. The evaluation is given in terms of bit error rate as a function of the signal-to-noise ratio for 4-QAM and 16-QAM modulations. The effectiveness of the STBC-OFDM communication system over the multipath and scatters-rich underground mine radio channel is highlighted. The simulation results show an improvement of about 10 dB for STBC-OFDM over SISO-OFDM.

ABSTRACT. Fading models of practical mobile radio channel may change over time and/or due to mobility being Rice, Rayleigh, double-Rayleigh, etc, depending on the nature of radio wave propagation, which results in a non-stationary channel. This work is based on investigation of fading figure (FF) that addresses non-stationarity nature of radio channels. The FF is represented by the parameter m of Nakagami-m distribution. For an indoor environment system, our results show the parameter m, which can be modeled as a generalized extreme value distribution. . The statistical distribution model of parameter m can be used to study performance of wireless communication system under non-stationary radio channels.

ABSTRACT. This paper presents the electromagnetic wave propagation in deep underground oil pipelines. The aim of this work is to analyze the attenuation of the electromagnetic waves in the pipelines caused by the oil medium under high temperature conditions. The work involves the modeling of a downhole oil pipeline. The simulations are focused on computing the scattering parameters (S-parameters) of the electromagnetic waves that propagate inside the pipeline filled with oil under varying temperature conditions. These results will be helpful to ascertain the possibilities of the wireless communication in deep underground oil pipelines.

ABSTRACT. In this paper, a photonic crystal sensor based on nano-resonator is designed and simulated for biosensing applications (DNA identification). The structure of the biosensor contains two waveguides and a nano-resonator. By binding the biological molecular to sensing hole, the resonance wavelengths will be shifted. The sensor is simulated for detecting of DNA and its quality factor is obtained as 2530. Also, the results show that the sensitivity is 9.48 nm/fg.

ABSTRACT. As a result of the growing usage of wireless devices and a large number of WLANs installations at schools; determining the exposure levels to students and staff from these systems has become more crucial than before. Since microwave radio links are used to provide connection between wireless devices, proper assessment of exposure to microwave emissions must be carried out. For this reason, in this study electromagnetic radiation (EMR) measurements were conducted at 92 different schools in Ilkadim district twice in 2016 using PMM 8053 EMR meter. The changes in and statistical properties of electric field strengths (E) are determined on the basis of these measurements. The maximum Es (Emax) are 5.39 V/m and 3.04 V/m for each measurement while the maximum average Es (Eavg) are 2.22 and 2.25 V/m. Even though the measured E levels are below the limits that are determined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP); for providing a wide margin of protection and evaluating the health risks they may cause, regular control/measurement of exposed EMR levels is recommended.

ABSTRACT. A novel microstrip antenna consists of conducting circular patch with elliptical etched rings and partial conducting ground plane is selected with fabrication dimensions of 45 mm×31 mm×1.27 mm, the design was fabricated using Rogers 5880 LZ substrate. Split Ring Resonators (SRRs) will be used to enhance gain performance for wide frequency band. The Split Ring Resonator design will be simulated using HFSS (High Frequency Structure Simulator). The final results of simulated antenna along with SRR group delay, maximum antenna gain, radiation pattern, S11 and VSWR will be presented. The presented antenna achieved the desired BW and the simulated S11 and VSWR are coherent and show unique performance.

ABSTRACT. A novel compact slow wave structure (SWS) based on spoof plasmonic waveguide with meander lines in the terahertz (THz) and microwave frequency range is proposed. The use of the meander lines increases the effective length of the proposed structure thereby providing more path length for efficient trapping of the spoof surface plasmon polaritrons (SPPs). The meander line based SPPs structure is designed in THz and microwave frequency range using the full wave electromagnetic field simulator, the CST Studio. The area of proposed SWS is found to be reduced by 75% as compared to that of the conventional rectangular based surface plasmonic waveguide structure. The experimental verification of the proposed SWS is carried out in the microwave frequency band by fabricating the scaled up version, and measuring the transmission coefficient data using the network analyzer.

ABSTRACT. Graphene-enabled wireless communications create an innovative archetype proposed to implement wireless communications at the nanoscale. Indeed, graphene-based nanoantennas, or graphennas, are few micrometers in size. Such antennas have been predicted to radiate electromagnetic waves at the Terahertz band. Hence, they do not only provide better integrability for future miniaturized wireless systems but also represent an enabling technology for applications such as wireless nano-sensor networks and Internet-of-Things (IoT). This paper surveys the existing research which investigates the state-of-art of graphene-based plasmonic nano-antennas. The paper focuses on the propagation of Surface Plasmon Polariton (SPP) waves since they set up the main characteristics of these antennas. Various fundamental properties of graphennas are also discussed providing useful guidelines for future designers of nano-antennas. The paper also addresses the future research areas of graphene-based Terahertz nano-antennas.

ABSTRACT. In this paper, some of planar metal-plate antenna designs, which are made of Shape Memory Alloy NiTi, have been discussed. Shape memory materials, especially NiTi, can be an alternative to conventional metals in terms of its good characteristics of higher strength, corrosion resistance, ductility, high recoverable deformation, relatively high electrical conductivity, and biocompatibility. In this work the names of these antennas are called ‘Circular NiTi Plate Antenna’ and ‘Flat NiTi Plate Antenna’ which have been designed according to dual band 2.4 GHz and 5GHz Band. These antennas are fabricated from a one-piece equiatomic NiTi plate, which is Metal-plate, therefore they have better gain and radiation efficiency performance. The performance tests have been done in free space conditions and also in an oven which has metal housing effect. The antennas show stable gain and radiation patterns over the 2 GHz and 5 GHz Band in both free space conditions and metal environment.

ABSTRACT. In this paper, a method of designing an autonomous Wireless Sensor Node (WSN) powered by RF energy Harvesting is proposed. The autonomous sensor node is composed of two components, the WSN and the RF energy harvesting system. The RF harvester is based on a rectenna that consists of an antenna associated with a rectifier circuit. The used rectifier circuit is an optimized Schenkel voltage doubler rectifier.The designed harvester show a recovered DC power of 115.7 μW with 0.27 V of the output voltage at 0 dBm of input power. A material block-level modeling of a WSN in a star topology network is proposed and used to estimate the energetic budget of the node. The sensor node performance is then evaluated regarding packet size and time ratio between standby and active state. It is observed that the recovered RF power allows considering a minimum transmit packet size of 801 bits for applications where measurements are made every 100 s.

ABSTRACT. The energy consumption is one of the main problems which remain to be addressed in wireless sensor networks (WSNs). Therefore, in recent years several clustering routing protocols for homogeneous and heterogeneous sensor networks have been proposed since these protocols are playing a key role in reducing energy consumption of the WSNs. A new Multi-Level Energy-Efficient Clustering (MLEEC) heterogeneous protocol is reported in this paper, where an optimal clustering and a threshold for Cluster Head (CH) election are proposed. The numerical results obtained show that the proposed protocol exceeds the performance of existing representatives of heterogeneous WSN routing protocols in term of lifetime and the number of messages received by the sink node. In addition, the balancing of the energy dissipated between the nodes is more important than for the other protocols.

ABSTRACT. A new approach has been considered to detect threat item among multiple concealed objects by analysing the delayed time- response of the objects, that would be illuminated by an ultra wide band radar. It was observed that the reflected wave, from the target, produced a delayed damped sinusoidal oscillation, that contained aspect independent complex natural resonances, which was unique for any individual object. A generalized pencil of function is applied for signal processing to extract poles from the scattered late time response of different objects. Application of hamming window function improves discrimination and detection of poles of multiple objects. Determination of the presence of a particular pole or concealed threat is observed upon using this proposed methodology. .

ABSTRACT. Massive multiple-input multiple-output (MIMO) as a promising air interface technology refers to the idea of equipping cellular base stations (BSs) with a huge number of antenna elements. Massive MIMO technology allows for orders of magnitude enhancement in spectral and energy efficiency requirement demanded by the fifth generation (5G) wireless communications. Accurate channel models that reflect important channel characteristics are very essential to efficiently evaluate massive MIMO technology in more realistic scenarios. Considering the very large electrical size of the Massive MIMO antennas, the shadow fading is a significant phenomenon can be seen across different elements of these arrays. This phenomenon needs to be modeled in order to have an accurate massive MIMO channel model. The purpose of this paper is to investigate the effects of shadow fading along the elements of the uniform linear massive MIMO arrays. To this end, an autocorrelation model of shadow fading is applied to generate the correlated fading coefficients from the uncorrelated ones. These correlated fading coefficients are applied to obtain the modified channel matrix. Some numerical simulations are presented to investigate how such a shadow fading along the Massive MIMO arrays can effect on the channel capacity of the system.

ABSTRACT. Mobile usage has seen unprecedented growth in the last decade. In 2001, cell phone subscriptions were less than a billion worldwide, while at the end of 2010, cell phone sub- scriptions had reached five billion worldwide. Modern day cell- phones provide many facilities other than audio and texting like MMS, email, GPRS, Bluetooth, infrared. However, in addition to positive aspects, any misuse of cell-phone, particularly by the teenagers, has many negative aspects. To reduce negative impacts of excessive use of cell phones, cell phone activity monitoring can be quite helpful. In this research, we will develop a system for cellular activity based human behavior modeling to differentiate abnormal cell phone usage. The proposed system employs spectrum sensing based on RF energy detection and Hidden Markov Modeling for classifying abnormal cell phone usage and inherently preserves the privacy of conversation or information content.

ABSTRACT. This paper presents an efficient parameter extraction method applied to GaN high electron mobility transistors (HEMTs) for mm-wave applications. The procedure is based on S-parameters measurements at cold bias condition to extract the parameters of a 19-element small-signal model. Hybrid technique of particle-swarm-optimization and direct fitting has been developed and implemented. The extraction procedure has been optimized to consider measurements uncertainty and improve the reliability of the extraction. The model has been validated by S-parameters measurements at different bias conditions and wide frequency range. A very good agreement between simulations and measurements has been obtained.

ABSTRACT. Microwave-based security camera systems have been implemented using different types of instruments to attain a real time, high resolution image representing dangerous concealed carry-on objects on people. Some designs achieved this goal but at a very high manufacturing cost that made them impractical as well as unfeasible. Moreover, such designs were made of a single receiver that led to loss of some important information. Therefore, the development of a two-dimensional microwave camera system at lower cost and high resolution is necessary. The main objective of this paper is to design, build, and test a high resolution, real-time low-cost camera system for security purposes. Furthermore, the proposed system addresses the development of a two-dimensional microwave imaging system that reveals the internal layers of non-transparent objects, based on the differences in dielectric constant of different materials. The objective is achieved by analyzing previous designs of microwave cameras to propose a cheaper system, which is implemented.

ABSTRACT. A novel pressure sensing circuit for non-invasive RF/microwave blood glucose sensors is presented in this paper. RF sensors are of interest to researchers for measuring blood glucose levels non-invasively. For the measurements, the finger is a popular site that has a good amount of blood supply. When a finger is placed on top of the RF sensor, the electromagnetic fields radiating from the sensor interact with the blood in the finger and the resulting sensor response depends on the permittivity of the blood. The varying glucose level in the blood results in a permittivity change causing a shift in the sensor’s response. Therefore, by observing the sensor’s frequency response it may be possible to predict the blood glucose level. However, there are two crucial points in taking and subsequently predicting the blood glucose level. These points are; the position of the finger on the sensor and the pressure applied onto the sensor. A variation in the glucose level causes a very small frequency shift. However, finger positioning and applying inconsistent pressure have more pronounced effect on the sensor response. For this reason, it may not be possible to take a correct reading if these effects are not considered carefully. Two novel pressure sensing circuits are proposed and presented in this paper to accurately monitor the pressure applied.

ABSTRACT. This paper presents the robust characterization of nonlinear microwave devices driven by broadband modulated multi-sine stimuli by using a refined multi-tone waveform measurement system. The substantial contribution comes from the capability of the measurement system to measure and average the time domain waveforms of adjacently modulated signals on a similar time scale for different modulation frequencies. The enhanced system demonstrates the ability of presenting the constant baseband (IF) loads across wide modulation bandwidth which is extremely imperative for the precise evaluation of inherent nonlinearity of microwave devices. The measurement system is later applied for the experimental investigations of baseband impedance variation effects on 10W GaN HEMT through the optimization scheme based on the simultaneously engineering of significant baseband components(IF1 and IF2) and higher baseband components(IF3 and IF4).

ABSTRACT. A new diplexer for wireless local area network applications using a combination of a multi-finger periodic structure and a novel Wilkinson power divider is proposed. The design consists of transmitting and receiving bandpass filters using the interdigital capacitor based on the theory of quasi-lumped element equivalency. The filters rely on the capacitance occurring across the narrow gaps between the conductors. Size miniaturization becomes feasible as the gaps are folded in order to use a small amount of area. The resulting design is investigated using the commercially available numerical solver and subsequently prototyped. Findings indicate acceptable agreement between the measured and simulated results.

ABSTRACT. A compact, tuning-fork, microstrip-fed monopole antenna and a classical triangular patch antenna operating at 5.5 GHz for WiMAX and 5.2/5.8 GHz for WLAN and ISM are presented. The antenna fork features an arm with a slit, which improves the gain by 12% compared with fork antenna without slit. The antenna offers 1 GHz, 2:1 VSWR bandwidth. The proposed antenna has a compact size of 21 mm X 13 mm, resulting in a 65% area reduction compared with the classical quarter wave monopole antenna operating at the same frequency. The performance of the proposed antenna is compared with a classical triangular patch antenna operating at the same frequency. The monopole fork antenna obtained 35% area reduction compared to the triangular patch antenna. For all antennas, simulation and measurement data are compared. The antenna’s compact size and low conductive area make it suitable for printed flexible circuit applications.

ABSTRACT. This paper presents a symmetrical layered design of integrated on-chip antennas for wireless inter-chip communication. The proposed symmetrical layered on-chip antenna structure has the advantage of canceling the effect of destructive multipath interference, encountered due to wave propagation from the transmitting antenna to the receiving antenna. The proposed symmetrical structure is simulated for two linear dipole antennas spaced 2cm on a silicon substrate. Simulation is carried out using ADS Momentum full-wave electromagnetic simulator. Results show a 10dB improvement in the overall transmission gain for the symmetrical layered structure over the unsymmetrical one. This verifies the feasibility of using the proposed symmetrical layered structure when designing on-chip antennas for inter-chip and chip-to-chip wireless communications.

ABSTRACT. An L-band 2x16 phased array antenna with printed dipole and integrated balun using multi-layering technique has been proposed. The design satisfies some targeted specification such as having a gain of 20 dB and a steering coverage of 90◦ at the center frequency 1.28 GHz. A sixteen-element linear antenna array is designed and fabricated. Simulation and experimental results of active reflection at port 1, 9 and 16, including gain performance at boresight, and side lobe losses (SLL) levels are presented.

ABSTRACT. Passive point targets such as trihedral and dihedral corner reflectors are commonly used for synthetic aperture radar calibration because of their large radar cross section and wide radar cross section pattern. These types of passive point targets are not expensive to manufacture comparing to active point targets such as transponder and they are easy to deploy in the field without using power to work. Perforating the corner reflector is an important factor in building the corner reflectors to allow quick drainage from heavy rain, cleaning from dust and reduce the effect of wind as well as reducing the weight of the corner reflectors. In this paper, we analysis the effect of perforating the corner reflector on maximum radar cross section using square trihedral corner reflector with four different hole sizes and three varying hole centre spacings. The results showed that a hole size of one-tenth of the wavelength reduced the maximum radar cross section by less than 1 dB from the theoretical radar cross section and the spacing between the two holes did not have much effect while one-sixth of the wavelength reduced the maximum radar cross section by about 1 dB and the reduction between the spacing is very small about 0.10 dB. Finally, a hole size with one-fourth of the wavelength reduced the maximum radar cross section by more than 2 dB and the reduction between the spacing increased while one-third of the wavelength has a reduction of about 4 dB.

ABSTRACT. In this paper, a printed monopole based multipleinput- multiple-output (MIMO) antenna system is presented for 4G applications. The MIMO antenna system consists of 10- elements. It operates at 2.1 GHz. The proposed design is simple, low profile and suitable for wireless handheld devices and mobile terminals. The MIMO antenna is fabricated on a commercially available FR4 substrate with Er equal to 4.3. The overall of board size is 115x65 mm2 which embodiments a typical smart phone back plane size. The single element size is 9x8.6 mm2.

ABSTRACT. A miniaturized ultrawideband (UWB) multiple-input multiple-output (MIMO) antenna with reconfigurable band-notched characteristics is examined in this paper. The MIMO antennas exhibit a good impedance match over frequency band of 2.5 GHz – 10.4 GHz, while exhibiting high isolation. The proposed MIMO antenna system consists of two complementary radiating patches and a common ground plane. Enhanced isolation is achieved with a ground structure consisting of a strip line and a slotted circular ring at the center. The decoupling structure provides isolation of more than 25 dB over whole UWB band spectrum. Moreover, the reconfigurable band-notch characteristic is achieved by introducing switches to quarter-wave slots in the main radiators. The notch is achieved for WLAN 5.5 GHz (5.15-5.825 GHz). The proposed antenna results suggests that the antenna design is suitable for UWB-MIMO applications.

ABSTRACT. Bandstop filters (BSFs) are highly required in modern wireless communication and electromagnetic compatibility related applications. In this paper, a fractal based dual-mode microstrip BSF has been proposed as a compact resonator structure with high selectivity. Filter miniaturization results from the application of Minkowski fractal geometry on the conventional triangle dual-mode resonator. Performance evaluation of the proposed filter design has been performed using the commercially available EM simulator; Sonnet. Parametric study reveals that the application of Minkowski fractal geometry results in BSFs offering both a compact size and high selectivity stopband responses. The results show that the proposed BSF over performs those reported in the literature in both the size reduction and the realized selectivity.

ABSTRACT. the advantage of unidirectional radiation patterns is offred by quasi-Yagi antenna. this letters present , a Frequency reconfigurable wideband planar printed quasi-Yagi antenna fed by a microstrip line to slot line transition structure and two parasitic strips as directors. The transition feed consists of a microstrip circular stub and a slot circular stub, with radii different to achieve wideband impedance matching. The reconfigurability of this antenna can be achieved by varying length of Transmission Line Resonator, this resonators placed in bottom part of slot line transition. The use of ideal switches will help to vary the length of resonators. Simulated results of antenna, with an ideal switch, fully demonstrate the performances of the proposed designs.

ABSTRACT. In this paper, a wide-radiation bandwidth and high-gain Faby-Pérot antenna is presented. The radiating system is composed of a complementary partially reflective surface (PRS)superstrate fed by an isosceles triangle slot antenna for the Ku-band applications. The PRS structure is composed of square slots loaded metallic plate and square apertures loaded patches printed on the bottom and top sides of the PRS, respectively. It is numerically demonstrated that the Faby-Pérot antenna has an impedance bandwidth of 13 %. Moreover, the antenna gain increases by about 9.55 dBi with a peak gain of 14.82 dBi and 3-dB gain bandwidth of 16 %.

ABSTRACT. In this article, a printed planar low VSWR monopole antenna with a new modified ground plane for ultrawideband (UWB) and 2.6 GHz LTE-band applications is presented. The dimensions of proposed antenna structure are optimized to achieve low VSWR performance. The antenna is fabricated on a low cost FR4 epoxy substrate and tested. The proposed antenna return loss is below −15 dB within bandwidth 2.5-13.2 GHz. The antenna has an omni-directional radiation patterns. The measured results show a good resemblance with simulated results.

ABSTRACT. A dual wide-band Quasi-Yagi antenna with loop excitation and it’s 52% miniaturized model using novel defected ground structure (DGS) is presented, targeting the 2 GHz band. The proposed dual wide-band antenna system has a measured bandwidth of around 1 GHz in both bands that cover 1:45-2:55 GHz and 3:707-4:71 GHz bands including GPS, GSM/EDGE, UMTS/HSDPA, Bluetooth, Wi-Fi, and WiMAX bands. The miniaturized version has a measured bandwidth of 1:5 GHz in the lower band while 620 MHz in the upper band. The size of the antenna without DGS is 78 117:5 mm2. It has a gain of 5:94 dBi, directivity of 6:21 dB, and front-to-back ratio (FBR) of 9:5 dB. The miniaturized antenna has a size of 5580 mm2. It has a gain of 4:23 dBi, directivity of 4:33 dB, and FBR of 8:5 dB. Both designs have efficiencies around 92%. The superior performance of the antenna without DGS in terms of FBR, gain, and directivity, comes at the cost of 52% larger size.

ABSTRACT. This paper presents a compact triple mode band pass filter (BPF) using dielectric-loaded cylindrical cavity that allows the realization of three transmission zeros. This class of triple mode resonator utilizes the dual degenerate TE11modes and the single TM01 mode. Coupling structure is based on choosing the proper resonator height and input/output feeding probe position (angle Ø) to achieve the desired perturbation between the degenerate modes. Therefore, no additional space nor coupling screws is needed. A three-pole BPF is designed to verify this approach at 2.08 GHz centre frequency with bandwidth of 42 MHz at -20 dB return loss. The introduced triple mode resonator can be used as a building block in the design of diplexers and sophisticated higher order filters.

ABSTRACT. Design of a wideband cascaded unit element microstrip bandpass filter (UEBPF) operating along the whole X-band (8-12 GHz) is presented with satisfactory agreement between theoretical and measurement results. Simplified real frequency technique (SRFTs) has been utilized in Richards domain to design the UEBPF, whose driving point impedance function is then synthesized by a “high precision Richards immittance synthesis package” in Matlab, Theoretical design, simulation and measurement results are shown to be in a good agreement with each other.

ABSTRACT. This work demonstrates the design of an adaptive reconfigurable rectifier to overcome the issue of early breakdown voltage in a conventional rectifier and extends the rectifier’s operation for wide dynamic input power range. A depletion-mode field-effect transistor has been introduced to operate as a switch and compensate at low and high input power levels for rectifier. This design achieves 40% of RF-DC power conversion efficiency over a wide dynamic input power range from -10 dBm to 27 dBm, while exhibiting 78% of peak power efficiency at 22 dBm. The power harvesters is designed to operate in the 900 MHz ISM band and suitable for Wireless Power Transfer applications.

ABSTRACT. In this paper, new polynomial and neural network models for power amplifier digital pre-distortion are introduced. The motivation behind the suggested models is having low complexity models that maintain good error performances. Also, this paper discusses the comparison between polynomial and neural network models in terms of model complexity and error performance before and after applying a compressed sensing algorithm. Furthermore, the proposed neural network model is a low complexity model that does not require a compressed sensing algorithm to reduce its number of model parameters, yet the proposed neural network model achieves good NMSE(dB) error performance.

ABSTRACT. We present a simple design of Quarter-Wave Plate (QWP) and Half-Wave Plate (HWP) all-dielectric metasurfaces based on Elliptic Dielectric Resonators (EDRs) of minor radius 2.5 mm, ellipticity tau (1=1.4,2=1.6 ), relative permittivity 10.2, loss tangent 0.003 and thickness 5.12 mm. The metasurfaces transmissions under x- and y-polarizations of the incident electric fields were studied over the microwave band 20-30 GHz. By optimizing the different design parameters such as the EDR ellipticity and orientation, we have realized both QWP and HWP metasurfaces with good performances.

ABSTRACT. We investigated numerically the design of all-dielectric metasurface based on elliptic dielectric resonators (EDRs) operating between 20 and 30 GHz. The effect of the resonator geometry (size, thickness, and ellipticity) on the metasurface transmission was studied from simulated modules and phases of both x- and y- polarized incident and transmitted waves.