This article presents a textile dual band antenna printed on an artificial heart (AH) bag for various Wireless Body Area Network (WBAN) communications. The textile dual band antenna operates at two different operating frequencies 2.4 GHz and 5 GHz. The two operating frequencies are reserved for IEEE 802.11b/g/n/ax and IEEE 802.11j WLAN standard. The designed antenna has a frequency bandwidth of (2.3642-2.5375 GHz) for the lower frequency of 2.4 GHz and (4.598-5.1683 GHz) for the upper frequency of 5 GHz. The dual band antenna is integrated with the proposed AH bag that is made from textile material. The effects of both different materials and dimensions of the proposed AH bag in the characteristics of the proposed antenna are investigated. The effect of the human body on the electrical performance of the proposed antenna integrated with the AH bag is presented. The amount of electromagnetic absorbed energy through the human body is also determined in terms of the specific absorption rate (SAR). The obtained SAR value is less than 0.12 W/Kg. This value meets the IEEE standards. Experimental verification for antenna integrated with AH bag and human body is presented.
This paper proposes a novel asymmetric interior stator topology for torque enhancement and torque ripple reduction in external rotor switched reluctance motor (ERSRM). The new topology and operational principle are first investigated using a simplified linear model. Then, the parametric model of the ERSRM and the comprehensive sensitive analysis that evaluates the influence of each design variable on optimization objectives are presented. Thirdly, the optimal design is selected from the Pareto front which is generated by NSGA-II (fast non-dominated sorting genetic algorithm) and validated by finite element analysis. Finally, the optimal prototype motor is manufactured, and experimental results confirm the validity and superiority of the optimized design.
A high-efficiency interaction circuit for Ka-band klystron has been proposed based on a novel internal coupling cavity. Driven by a 25 kV, 5 A pencil beam, the interaction circuit can produce a peak output power of 38.4 kW at Ka-band, and the electronic efficiency is 30.7%. The electromagnetic properties of the unequal slot multi-gap cavity and internal coupling cavity have been studied and compared. The internal coupling cavity demonstrated a higher coupling coefficient and characteristic impedance than the unequal slot multi-gap cavity, which can improve the circuit efficiency. Stability and pattern analysis have been performed on the output cavity. A four-gap output cavity has been designed. Simulation results show that there is no mode competition and oscillation in the output cavity. The corresponding beam optics has also been designed to produce the required beam. Compared with the existing work, the interaction circuit can produce almost twice the output power with the same beam voltage and Brillouin focusing magnetic field. The efficiency is also improved by 6 percent.
This article proposes a 4-port MIMO antenna for 5G mid band application resonating from 4.5-5.1 GHz which comes under n79 band, an FR1 5G NR band used in smart phones. The first design involves a single-element microstrip patch antenna with a diamond shaped slots and partial ground structure of size 30 × 43 × 1.6 mm3. Using this single element antenna as reference, a 4 port MIMO antenna is presented which operates at 4.9 GHz resonance frequency with proper spacing, resulting in much improved isolation between the elements. The proposed 4 port MIMO antenna is designed and fabricated over a commercially available low-cost FR-4 substrate having a relative dielectric permittivity of 4.4 and thickness of 1.6 mm. The W × L dimension of this MIMO antenna is 56 × 56 mm2. Simulation of the S-parameters and radiation pattern of all purposed designs is performed using the CST studio suite, and test results of the return loss are presented using the Keysight N9916A 14 GHz vector network analyzer. Antenna gain is 3.8 dB, and efficiency is 87% with a low (less than 0.1) envelope correlation coefficient (ECC) between any two radiating elements, paired with a positive diversity gain (DG), indicating that the proposed antenna is well designed. As a result, the proposed antenna is an excellent candidate for deployment in 5G networks.
This paper demonstrates a compact two-port multi-input multi-output optical nano-antenna with polarization diversity. The proposed antenna consists of a silicon-based radiating element that explores the possibilities of using a highly efficient dielectric resonator over the conventional metallic antennas at THz regime The specific position of the Gaussian pulse excitation generates the 90° phase difference between the field components travelling across the edges of the silver nanostrip feedlines. This generates the orthogonal field components which results in the achievement of circular polarization. Furthermore, any deviation in the excitation position at the port disturbs the field components resulting in linear polarization. This approach provides the polarization diversity using different excitation positions at ports. Considering the analytical stage of this proposed work, the detailed design guidelines and analysis are also discussed. The antenna provides circularly polarized radiations having 6.78% of 3 dB axial-ratio bandwidth and linearly polarized response using the optimized feeding positions at the respective ports for obtaining the polarization diversity performance. The isolation of more than 15 dB is maintained between the ports over the entire operating passband of the antenna. The proposed antenna with the optimized dimensions can be utilized for the optical C- and L-band applications.
Thinner substrate designs of square and circular microstrip antennas using fractal variations of U-shape and half U-shape slot cut ground plane are proposed for circularly polarized response. The 1st, 2nd, and 3rd order fractal variations of slots on the ground plane are studied. The fractal slot cut variations degenerate patch fundamental mode into dual orthogonal resonant modes, and an optimum spacing between them yields circularly polarized characteristics. Amongst all the designs, circular microstrip antenna using the 1st order fractal U-slot design yields optimum result. It offers axial ratio bandwidth of 60 MHz (2.14%) with a broadside radiation pattern and peak gain of 5.5 dBi, on a substrate of 0.02λg thickness and patch area 1.44λg. Against the reported designs, the current work presents a low profile single patch circularly polarized configuration.
For the research of 5G NR band mobile phone bezel antenna, this paper proposes an 8-Element Multiple-Input Multiple-Output (MIMO) handset bezel antenna design for 5G New Radio (5G NR) bands. Moreover, the MIMO antenna's array is implemented by loading 8 identical antennas (Ant1-Ant8) into the metal bezel of the smartphone to form an 8-antenna array for a sub-6 GHz 8×8 MIMO system. In this setting, each antenna unit is a slot antenna type consisting of a Chinese character ``卫''-shaped slot, as well as a 50 Ω micro-strip feeder; note that a satisfactory impedance matching is achievable in the upper-frequency band by loading a tuning stub on the feeder. The proposed 8-element antenna array covers 5G new radio (NR) band including N77 (3.3-4.2 GHz), N78 (3.3-3.8 GHz), N79 (4.4-5.0 GHz), and a Wi-Fi (2.4 GHz) band with a 10 dB impedance bandwidth. It is important to note that in addition to exhibiting ideal antenna efficiency and envelope correlation, the isolation between adjacent array elements is >10 dB, and the peak gain is 3 dBi. In summary, the influence of the user's hand on the antenna is analyzed to ensure the robustness of the MIMO antenna system in practical applications.
This study presents the generation of a scalable model based on measurement aided numerical calculations for MiMCap (Metal-Insulator-Metal Capacitor) structures with a 0.25 µm SiGe-C BiCMOS technology. Various MiM capacitor structures with several different area and peripheral sizes are fabricated in an in-house developed BiCMOS process. A set of fix-size models and a generic scalable model are developed based on numerical EM calculations. The validity of the constructed model is verified with the measurement results. The model includes the breakdown voltage ratings which are also extracted through the measurements. The model, EM simulations and measurement results are in good agreement.
Through wall radar imaging and detection applications are growing significantly. However, the target response is usually accompanied with a strong clutter which veils the target detection. In this paper, a new algorithm is proposed for clutter reduction and target downrange correction in through wall monostatic radar imaging. The proposed algorithm arranges the received radar signals in a matrix and then splits this matrix to frames. The frames are individually processed and filtered in frequency domain, then they are returned to time domain and merged together in a new matrix. The final step is enhancing the target response via a matched filter. The proposed algorithm performance is evaluated by target to clutter ratio (TCR), signal to clutter ratio (SCR), and downrange target position error (DTPE) in three different simulated scenarios. The simulation results exhibit the proposed algorithm capability in both removing the clutter and adjusting the target downrange to be with an evident appearance and accurate position. In the most complicated scenario which consists of two separated walls and a target behind them, using the proposed algorithm improves the performance in terms of TCR, SCR and DTPE by 49.7 dB, 70.7 dB, and, 7.6% respectively.
This paper presents a narrow notch band, flexible, wearable ultra-wideband antenna built on a jeans substrate. Prior to designing the antenna, the dielectric properties of the jeans substrate are experimentally investigated. The effects of antenna shape and substrate loss characteristics on resonant performances are discussed with reference to the notch characteristics. The proposed antenna is shaped like a cumulative rugged element, with two identical legs. The investigation of the designed antenna shows the operating frequency ranges (S11 ≤ -10 dB) in 2.4-4.2 GHz and 5.86-10.7 GHz bands with notch properties in telemetry/mobile communications (4.4-4.99 GHz) and WLAN (5.15-5.85 GHz) band. Additionally, the prototype is investigated under on-body conditions. Measured results are also included for the validation of the designed prototype.
This paper presents a novel reverse salient pole flux controllable permanent magnet (RSP-FCPM) motor topology, and the motor rotor is reasonably designed to have reverse salient pole characteristics and flux controllable characteristics. After selecting the design variables for the RSP-FCPM motor using sensitivity analysis, a multi-objective genetic algorithm is applied for multi-objective optimization. The optimized RSP-FCPM motor is simulated and compared, and the results show that the optimal RSP-FCPM motor has better flux weakening capability, wider speed range, and constant power output area. it can solve the problem of difficult flux changes of the conventional interior permanent magnet motor, and other electromagnetic performances are also more advantageous. To confirm the reliability of the rotor structure during operation, a stress analysis of the rotor is performed, and the results show that the rotor structure can fully withstand high-speed and high-temperature conditions and can operate safely and stably. It also has more advantages in noise performance, which has great prospects for application in the field of electric vehicles.
A novel variable flux permanent magnet vernier machine (VFPMVM) is proposed by introducing the concept of hybrid excitation, and its flux modulation poles (FMPs) and excitation winding are emplaced in stator teeth and the adjacent FMPs, respectively. It can offer several merits, such as wide speed range operation through the processing of flux-enhancing and flux-weakening without increasing machine bulk, as well as the numbers of stator slot and rotor pole. Moreover, as one sort of flux modulation machine based on magnetic field modulation effect, VFPMVM features low speed, large torque, simpler mechanical structure and better utilization of PM materials than traditional flux modulation machines. The working principle of proposed machine is studied, and basic electromagnetic characteristics are calculated by finite element method, including no-load magnetic flux linkage, no-load back electromotive force, cogging torque, and output torque. In addition, the processes of flux-enhancing and flux-weakening are analyzed. Finally, one prototype with one kilowatt was built, and its static characteristics were tested. The results show that the proposed VFPMVM has the merits of high torque density, small cogging torque, and wide speed range, which is a promising candidate for electric vehicle direct drive field.
In wireless technology, microstrip patch antennas are often used in communication systems with various designs. However, the effect of geometrically folded antennas on wireless communication performance is unclear. To address this problem, an in-depth study of the flexible antenna parameters was performed through V-folding analysis. A systematic and complete analysis of the percentage of folding in patch antennas was performed. The folding of patch antennas is expected to become mandatory because patch antennas are integrated and molded according to specified object shapes. The designed antenna was operated at 0.1-5.0 GHz to investigate the folding performance in the frequency range of 1.00-3.78 GHz used in many wireless applications, such as the GPS, GSM, and LTE standards. A promising operating frequency for flat (unfold) antennas is 1.42 GHz with an achieved multiband bandwidth of 31.6 MHz, which shifted according to the folding angle but with good performance. The results of this study can be used to predict the performance of an antenna when it is placed on a product of any shape, according to the designed object pattern.
A compact novel lamp slotted upper WLAN band rejected ultrawideband (UWB) radiator integrated with Ku and partial K bands is reported. The intended radiator consists of a novel lamp slotted patch structure with a 50 Ω tapered microstrip feed line along with a novel semicircular defected ground structure (SCS-DGS). The size of the suggested radiator is 16×22 mm2 with an impedance bandwidth ranging from 3.63 to 21.94 GHz to cover UWB integrated with Ku and partial K bands, and a novel via notched element is utilized to notch the upper WLAN band from 5.31 to 6.05 GHz. The proposed antenna has stable radiation patterns, consistent gain, and a peak radiation efficiency of 92.15% except for the notched band which mak it suitable for upper WLAN band notched UWB wireless communication applications.
This article presents a broadband circularly polarized (CP) semi-annular ring-shaped printed monopole antenna for wireless applications. A semi-annular monopole with symmetric partial ground plane is designed to achieve the impedance bandwidth with a behaviour of linearly polarized (LP) radiation wave. To achieve the CP behaviour with broadband axial ratio (AR) bandwidth, an asymmetric stair shaped partial ground plane is incorporated in the semi-annular ring-shaped monopole structure. Different analysis of CP radiation is presented by analysing the surface current distribution, electric field distribution and also its mathematical modelling using CST-MWS solver. Moreover, an equivalent circuit model of the proposed monopole antenna is developed using Foster canonical forms. The measured -10 dB impedance bandwidth and 3-dB AR bandwidth are 8.78 GHz [3.22-12.0 GHz] and 2.21 GHz [7.58-9.79 GHz] respectively. The peak realized gain and antenna efficiency are 4.32 dB at 7.61 GHz and 82% at 4.83 GHz respectively. The proposed antenna can be suitable for C-band (4-8 GHz) and X-band (8-12 GHz) applications.
An Ultra-wideband Microstrip fed patch antenna with a defective ground surface is presented in this paper. The above-mentioned antenna comprises a T-slot in the ground plane and a Pi-slot in a rectangular patch. The proposed antenna is developed and modeled using the High-Frequency Structure Simulation tool on an RTDuroid 5880 substrate with a thickness of 1.6 mm and a dielectric constant of 2.2. A T-shaped defect is carved in the ground plane to enhance the antenna's radiation properties, gain, and bandwidth. A conventional Pi-slotted patch antenna operating at 9.74 GHz with a return loss of 19.7 dB is designed, followed by an ultra-wideband antenna embedded with a T-slot in the partial ground surface operating from 7.15 GHz to 10.925 GHz with an impedance bandwidth (S11 < −10 dB) of 3.775 GHz. It showcases exceptional characteristics with a peak gain of 6.99 dBi at 8.95 GHz. A satisfactory agreement is found between the experimental data and simulation results. The proposed Pi-slot patch antenna with the defective ground has applications in radar, satellite, weather monitoring, and vehicle speed detection for law enforcement.
A design technique to develop the desired pattern with uniform spacing between elements for a resonant linear slot array on the broad wall of a rectangular waveguide is discussed in this study. First, linear array pattern synthesis is used to achieve the amplitude and phase of the array element. Then both radiation pattern synthesis and the array input impedance matching are achieved using the least-squares method. In addition, the error function is created by combining the three terms of impedance matching, array pattern synthesis, and slot design equations. Genetic algorithm (GA) and the conjugate gradient (CG) technique are used to minimize the acquired error function. The utilized approach results in precise pattern synthesis, good impedance matching, development of appropriate design equations, and power loss minimization. The computing needs were also reduced using the suggested antenna design. The approach is particularly beneficial since it integrates slot parameter dimensions and impedance matching with array pattern synthesis, resulting in a faster and more accurate design. Full-wave simulation Software HFSS was utilized to validate the suggested design method. Moreover, the measurements were conducted on a prototype designed to validate the simulation's accuracy and the designed antenna practicality, and excellent agreements between theoretical predictions and simulation results were achieved.
The narrow beam-width 120 GHz industry, scientific, and medical band compact substrate integrated waveguide (SIW) driven antenna's design and characterization are discussed in this study. A low-cost fabrication is ensured by the employment of a single RO4350B substrate layer with SIW feeding. A transition from SIW to a rectangular waveguide is made for measuring purposes. The radiation pattern has been measured. By determining the right feeding phases for the 20 elements, a Deep Neural Network (DNN) is used to softly compute the beam steering. The weighted hybrid Modified Gravitational Search Algorithm (MGSA) - Particle Swarm Optimization (PSO) approach and neural network with back-propagation technique are utilized to beam-steer by anticipating the appropriate feeding phases of the antenna array elements. To evaluate the effectiveness of the approaches, a number of sample instances are given that beam-steer the pattern in a variety of directions. In addition to allowing for the establishment of crucial analytical equations for the synthesis of antenna arrays, the neural network synthesis method also offers a great deal of flexibility between the system parameters in input and output, which makes the synthesis possible due to the explicit relationship given by them. The conventional technique of the phased array is compared with our DNN model for implementing beam steering.
A circularly polarized dual band wearable antenna using frequency selective surface backed reflector for radio frequency identification reader resonating at global ultra-high frequency band (860-960 MHz) & ISM band (2.4 GHz) is proposed in this work. For circular polarization, the corner is truncated at the opposite end of a square patch with periodic slots over the patch for getting an orthogonal electric field in both the X & Y axis direction. Another truncated inner square slot patch miniaturizes the antenna further for stable frequency response. Finally, the periodic frequency selective surface-based reflector is used for gain enhancement & crosstalk reduction. The simulated & measured results for antenna over human body are plotted against the required bandwidth. The return loss and maximum radiated gains of -31 dB and 8.30 dB are achieved at a resonating frequency of 2.4 GHz with the reading range and Specific Absorption Rate (SAR) of 6.98 m and 0.77 watt/kg respectively. At 865 MHz the return loss & maximum radiated gain is -23 dB & 5.31 dB with the reading range & SAR of 5.21 m & 0.65 watt/kg respectively. The proposed UHF RFID antenna is circularly polarized with the axial ratio bandwidth less than 3 dB with approximately 15% (860-965 MHz & 2.4-2.45 GHz) range. The designed wearable antenna provides better isolation when FSS is incorporated while enhancing the gain for longer read range. The FSS reflector below the antenna reduces the SAR for on-body wearable applications. This RFID antenna can be used efficiently for WBAN applications as a portable RFID reader wearable antenna for remote sensing & real time monitoring.
Interrupted Sampling Repeater Jamming (ISRJ) is an electronic countermeasure against radar echo signals that generates many false targets to mask the real target echoes, which seriously affects radar target detection performance. Most of the ISRJ suppression methods require accurate estimation of the signal parameters, and the estimation methods are complex. Based on the characteristics of discontinuous ISRJ sampling and orthogonality between multi-carrier phase coding (MCPC) signal's subcarriers, we propose a method for ISRJ identification and suppression based on an improved MCPC signal. By analyzing the pulse compression of the echo, we found that different types of intermittent sampling interference have different peaks after pulse compression. Based on this feature, we introduce Fractional Fourier Transform to filter out interference. Theoretical analysis and simulation results show that the method can effectively suppress the three classical ISRJ interferences. The method suppresses ISRJ during echo processing without any parameter estimation for real scenes and has stronger robustness than other existing schemes.