A novel high performance four-port multiple input multiple output antenna is suggested for 5G application functioning at 3.4 GHz band. The antenna design measures an inclusive volume of 32 mm x 32 mm x 0.8 mm3. The broad frequency bandwidth, excellent gain, decreased interelement gap, and effective isolation within the MIMO components of the proposed system are clearly novel. Each antenna in the four-element MIMO system has been situated orthogonally to the others while maintaining a small size and good result. The antenna has exceptional average total efficiency in the 5G Sub-6 GHz spectrum and is in good agreement with the measured results. It also offers a high realized gain compared to prior MIMO antennas. The antenna has a high impedance matching whose isolation is about -28 dB, computed envelope correlation coefficient smaller than 0.10, channel capacity loss average value less than 0.2\,bits per second per hertz, and the diversity gain about 10 dB. The typical peak realized antenna gain of the offered MIMO antenna is also delivered with a high radiation efficiency at the frequency of 3.4 GHz. The reflection coefficient, mutual coupling, radiation pattern, current distribution, and gain of antennas are all measured and explained. The design has a compact high volume and adequate bandwidth with good accomplished gain making the antenna very strong for 5G application.
A reconfigurable filter integrated single-pole double-throw (SPDT) switch (FIS) based on capacitor loaded ring resonators is presented in this paper. The design incorporates two PIN diodes between two symmetric square ring resonators. The ring resonators can be switched between allstop and bandpass responses, by adjusting the state of the PIN diodes, allowing the corresponding signal path to be in OFF-state with high isolation or ON-state with bandpass filter response. For demonstration, filtering switch is fabricated and measured for 2.4 GHz applications. The measurement results feature an ON-state low insertion loss of -2.1 dB and port-to-port isolation of -50 dB at the band of interest, and good consistency is achieved between simulated and measured results.
Dielectric logging is a valuable tool for locating and developing tight reservoirs, low contrast reservoirs, shale oil and gas reservoirs, and other unconventional oil and gas reservoirs. The processing of multi-frequency and multi-spacing dielectric logging measurements is based on a stable and efficient response computation algorithm. An equivalent computation model for the push-against-hole array dielectric logging tool is established in this paper, and an improved forward method based on the semi-analytical algorithm for dielectric logging response is devised. Thus the calculation speed of each measurement point's dielectric logging response is increased by more than 8 times. Dielectric logging response charts are also constructed, showing amplitude attenuation and phase shift as functions of formation resistivity and relative permittivity at various operating frequencies. The effects of mud cake, invasion, and anisotropy on the response signal are then simulated and evaluated. The findings reveal that: (1) as the high-frequency response changes significantly when the mud cake is thick, to correct the mud cake's influence, the mud cake parameters can be extracted using the high-frequency detection mode. (2) Invasion has a complicated effect on the high-frequency response, and higher resistivity or relative permittivity in the invasion zone can readily lead to an oscillatory nonlinear shift in the response as a function of invasion depth. This means that for high-resistivity and high-permittivity formations, the high-frequency response has a larger sensitivity and a deeper depth of investigation. (3) When the anisotropy coefficient is small, the high-frequency response is preferable for extracting anisotropy; however, as anisotropy increases, the low-frequency response becomes more sensitive to anisotropy than the high-frequency response.
In this paper, an analytical model is presented to investigate the resonant characteristics of a graphene rectangular microstrip patch antenna. To take into account the graphene film patch in the full-wave spectral domain technique, surface complex impedance is considered. This impedance is determined by using Kubo formula. A set of roof top sub-domain basis functions are employed to model the current density distribution on the graphene rectangular microstrip patch. The simulation results demonstrate that the designed structure can provide excellent tunable properties in Terahertz frequency region by varying different chemical potentials and relaxation times of graphene film. Variations of dimension of rectangular patch on the resonant frequency and bandwidth of a graphene rectangular microstrip antenna are presented. Finally, numerical results for the dielectric substrates effects on the operating frequencies are also presented. The analysis is validated by comparing the results with a specific example in the literature.
This study presents a quad-band bandpass filter with high selectivity, compact size, and highly independent bands using a folded C-shape resonator, short stub-SIR resonator, and two folded L-shape resonators. The suggested structure consists of two separate filters. The upper filter is made up of a short stub-SIR resonator loaded on a C-shape resonator resonating at 2.59 GHz and 3.5 GHz, respectively. The lower filter is made up of two folded L-shape resonators resonating at 4.89 GHz and 6.15 GHz, respectively. The frequencies at which the filter resonates are designed and arranged with high independence. The proposed filter achieves insertion loss of -2.7 dB, -0.7 dB, 2.3 dB, and -0.4 dB, and return loss of -13.32 dB, -11.03 dB, -9.17 dB, and -17.89 dB, respectively. In addition, eight transmission zeros appeared. The proposed design has a compact size of 0.19λg×0.15λg and is built on an RO4350B substrate with a dielectric constant of 3.66, loss tangent of 0.0037, and thickness of 0.508 mm. Finally, the suggested filter is intended to be used in 5G mobile communications and international mobile telecommunications services.
For the tracking problem of moving targets by small-scale platforms, this paper firstly proposed a ship target tracking model with joint electromagnetic signals based on point charge theory and point magnetic charge theory. Then, the target tracking was simulated and verified with the progressive update extended Kalman filter algorithm as the filtering unit and the small-scale platform as the sensor-carrying platform. Finally, the laboratory model validation was carried out, and the simulated source experiment and ship model experiment were conducted respectively. The simulation results show that the tracking method with the joint electromagnetic signal can achieve the tracking error less than 5 m in the range of 6 times the ship length. The results of the model experiments further verify the simulation results. When the signal-to-noise ratio is only 5, it can also achieve at least 2 times the ship's length of tracking, which can effectively solve the problem of poor tracking caused by the small size of the sensor carrying platform and the small number of sensors.
The wireless power transfer (WPT) system for implantable medical devices has the problem that the output voltage is difficult to adjust stably in real time without using additional composite compensation topology and dual-side communication. A primary side control method of WPT system based on a phase shifted full bridge inverter and continuous control set model predictive control (MPC) is proposed. First, the series-series (SS) structure parameters and fundamental harmonic analysis (FHA) are used to derive the estimated value of the output voltage and establish the output voltage prediction model of the system. Then, to obtain the best response of the system, the optimization problem in the controller is transformed into the problem of solving the minimum value of the cost function, and the optimal control variable is obtained limited below the gradient descent method. Simulated and experimental results show that the control system works at a frequency of 200 kHz to realize real-time voltage adjustment, and the steady-state error is within 2%. Compared with the traditional method, the method reduces the adjustment time by 5-10 ms, and voltage overshoot is reduced by 5.3-6.7% when interference factors are dealt with such as load interference and mutual inductance. The proposed method improves the performance of SS compensated WPT systems to be more suitable for the applications that require compact and light weight receiver. It provides an effective method to realize the real-time regulation of the system output voltage.
In this paper, a flexible compact Jeans gap filled metamaterial inspired antenna is proposed to operate at 2.4 GHz in the Industrial Scientific and Medical (ISM) band. This designed antenna is flexible having size of about 27×23 mm2 with substrate of thickness 0.3 mm. The proposed antenna comprises two complementary split ring resonators at ground plane and one circular ring and complementary rectangular split ring resonator. The top patch consists of two rectangular split ring resonators etched inside the rectangular patch. The use of SRR and CSRR on top and bottom of patch has helped to reduce the size of antenna along with maintaining performance of antenna. Further enhancements are done to make it jeans gap filled antenna with jeans filled between main patch and superstrate. The superstrate top patch consists of a square EBG structure. The simulation results have shown an increase in return loss due to the use of square EBG structure on superstrate. The simulated directivity obtained on antenna is 2.0775 dB. The measured and simulated results are in a good agreement. The motivation of this work is to design a compact metamaterial based antenna for wireless body area network with gap coupled jeans material to nullify effects of human body. Effects of air gap coupled and jeans gap coupled are analyzed in terms of performance. While the final antenna (Antenna-4) is designed, several iterations are tried to optimize and maintain good performance. Step 1 (Antenna-1) consists of two complementary split ring resonators along with a circular ring placed in ground plane with thickness of polyamide substrate as 0.3 mm. Step 2 (Antenna-2) consists of two split ring resonators along with a circular ring placed in ground plane. An air gap coupled superstrate is designed having gap between main patch and superstrate as 1 mm. Step 3 (Antenna-3) has the same configuration as Antenna-2, and the only difference is the air gap between main patch and superstrate which is replaced by jeans material. Step 4 (Antenna-4) is the final designed antenna with miniaturized size of 27×23 mm2 as compared with previous antenna configurations. This research work has identified the challenges involved for designing an antenna in a wireless body area network. Practical aspect of design needs to consider: a) Bending effect on performance as movement and physiological changes might affect the performance. b) Performance degrades when antenna comes in contact with human body. Bending Effect: This work has also analyzed effect of bending on return loss. For final designed antenna (Antenna-4) maximum bending up to bend 30˚ is possible. Further bending would break the substrate. After maximum bending, the measured return loss is about -16.7071 dB at 2.28 GHz. Body area network: The designed final antenna (Antenna-4) is tested on different parts of human body such as human-arm and leg. No major difference is seen on return loss when it is tested on different parts of body. The designed final antenna (Antenna-4) is tested on direct contact with human-arm as well as with different cloths (cotton jeans, cotton, curtain cloth, floor cloth, polyester and Turkish cloth) having different permittivities with the distance between cloth and antenna as 0 cm and 1 cm. Wearable antennas should be carefully constructed to avoid causing harm to the human body when being worn. The Low Specific Absorption Rate is one of the criteria that should be considered while developing a wearable antenna. The maximum allowable SAR limit is 1.6 W/kg. The specific absorption rate for Antenna-4 is 0.2 W/kg when input power is 1 watt and is 0.036 W/kg when input power is 100 milli watt. The results obtained show that the proposed antenna is both safe and acceptable for use in compliance with the World Health Organization's ICNIRP requirements.
In this article, the radiation properties of a slot-loaded cylindrical dielectric resonator antenna (CDRA) have been synthesized strategically to realize a dual-band operation with a higher gain. A microstrip line based aperture coupled feed is adopted to excite dual modes at 4.8 GHz and 8.28 GHz with an impedance bandwidth of 5.84% (280 MHz) and 10.62% (880 MHz), respectively. A superstrate layer is placed at a suitable gap above the antenna structure to enhance the antenna gain by utilizing the principle of multiple reflections. For the further improvement of gain, a plus-shaped slot is incorporated on the superstrate that helps to concentrate the radiated field at the center of the superstrate, thereby the directivity of the CDRA has been enhanced on a large scale. The proposed structure is fabricated and measured for experimental verifications that demonstrate 3 dB augmentations in antenna peak gain in comparison to the conventional CDRA. The experimental result shows a good agreement with the simulated ones. Higher measured peak gains of 7.87 dBi and 7.91 dBi at two operating bands ensure the applicability of the proposed simple structure for C-band high gain wireless applications.
A planar suspended multiband Yagi antenna suitable for WLAN, LTE and 5G wireless applications has been presented. The antenna presented here has been optimized to offer operating bands centered at 2.05 GHz, 2.75 GHz, 3.8 GHz, and 6.5 GHz. The proposed antenna has good front to back (F/B) ratios of 14 dB, 13 dB, 12 dB, and 19 dB corresponding to four resonant frequencies. Similarly, the corresponding gain values are 2 dB, 1.3 dB, 3.1 dB, and 3.3 dB. A prototype antenna was fabricated and tested. Except the first resonance which is a single frequency, the other three operating bands offer impedance bandwidths of 3.98% (2.71 GHz-2.82 GHz), 5.48% (3.73 GHz-3.94 GHz), and 19.27% (5.93 GHz-7.195 GHz). Measured results agree fairly with the simulated characteristics of the proposed antenna.
Magnetic coupling detection method, as one of the methods of solving grounding grid breakpoint location problem, has the problem that the size of the transmitting coil is too large to be easily applied to the actual environment detection. In order to reduce the size of the transmitting coil and ensure the effect of breakpoints detection, this paper studies the characteristics of the planar coil based on the method of grounding grid breakpoint magnetic coupling detection. Firstly, a mathematical model of the planar coil magnetically coupled detection grounding grid breakpoint system under high frequency is established. After analyzing the model, factors of affecting the breakpoint detection effect and the high frequency characteristics of the system are derived. Secondly, a simulation model of the magnetically coupled detection grounding grid is established by using HFSS software. The influence of the line width, side length, number of turns and turn spacing of the transmitting coil on the detection effect is studied in detail. Besides, according to the law, the coil size optimization design is carried out. At last, the experimental platform is built to verify the reliability of the simulation and theory. The results show that the detection effect decreases as the line width and side length of the planar coil decrease, but the effect of line width change is small. Increasing the number of turns and turn spacing can improve the coupling coefficient to increase the detection effect, but when the distortion region is located after the parallel resonance point, the distributed capacitance will greatly inhibit the detection effect.
A triangle-shaped proximity-fed circularly polarized antenna with a modified fractal ground structure is introduced in this paper. The antenna's ground plane is employed with a fractal-shaped corporate feed type cut, which helps produce the circular polarization. The proximity feed is offset from the center to generate the orthogonal modes; furthermore, the fractal modified ground aids in enhancing the axial ratio bandwidth. Different iterations of the basic fractal unit improve the polarization purity and the axial ratio bandwidth. The designed antenna reflection coefficients below -10 dB at 2.45 GHz show an impedance bandwidth of 250 MHz (2.25 GHz to 2.50 GHz) and axial ratio bandwidth of 90 MHz (2.40 GHz to 2.49 GHz). The simulated and measured results show a good agreement.
High frequency electromagnetic plane wave scattering by a large rectangular glass window on a conducting wall has been analyzed in this study. Scattering far-fields are formulated by means of the Kirchhoff approximation in which the fields are obtained from radiation integrals due to the equivalent current sources on the virtually closed window apertures. In order to consider the effect of the window glass, a dielectric slab layer has been inserted in the window hole, and the reflection and transmission through the slab are treated via waveguide modal theory. The validity of our formulation has been confirmed by the numerical comparison with another method for an empty window case. The effects of the window dimension, the glass layer, and the polarization have been discussed for practical high frequency mobile communications.
The present work proposes a novel cow-head shaped multiple input multiple output (MIMO) antenna for 5G sub: 6 GHz applications, which include N77/N78 (3.3-4.2 GHz/3.3-3.8 GHz) and N79 (4.4-5.0 GHz) bands. The proposed work is designed and developed on a 30 × 66 mm2 size FR4 substrate with a dielectric constant of 4.4 and loss of tangent of 0.002. The proposed design works in the region from 3.3 to 5 GHz, and an isolation above 18 dB is attained. The parametric analysis and surface current distribution are studied for the optimization of parameters, and the coupling between elements is analysed respectively. The performance of design is studied in terms of efficiency (≥ 91.5 %), peak gain (3.1-4.6 dBi) and radiation patterns (E & H fields). The diversity parameters (ECC, DG, TARC, CCL & MEG) are calculated and checked, the same as measured results. Then all the measured results of fabricated prototype is compared with simulated ones, and these are in good agreement.
This present article reports a high isolation four-port Wrench shaped compact UWB MIMO antenna with a novel decoupling network in the ground plane, and its step-by-step evolution is presented for 3.1-10.6 GHz. The proposed four-port MIMO antenna is fabricated on an FR4 substrate of size 44×44 mm2 (0.342λ0 × 0.342λ0), where λ0 is a free space wavelength at 2.33 GHz, with 7\,mm edge-to-edge spacing between the radiating elements. It consists of four orthogonal symmetrically placed identical radiating elements each of which has a Wrench-shaped circular patch with a rectangular slot cut in the partial ground. The performance characteristics of this MIMO antenna are reflection coefficients S11 ≤ -10 dB in the range from 2.33 GHz to 11.7 GHz, mutual coupling coefficients S21 ≤ -28.24 dB, and S31 ≤ -22.35 dB. The maximum peak gain is 5.15 dBi at 9.2 GHz, minimum is 1.27 dBi at 3.1 GHz. The maximum peak gain is 5.15\,dBi at 9.2 GHz, and minimum is 1.27 dBi at 3.1 GHz. The maximum efficiency is 98% at 4.66 GHz, and the minimum is 93% at 6 GHz. The diversity parameters of proposed four-port MIMO antenna are reported as ECC ≤ 0.2, DG ≤ 10, TARC ≤ -10 dB, the ratio of MEG between any two elements is near unity, and CCL < 0.38 bits/s/Hz in the band of interest. The design is fabricated and measured. The measured and simulated results are in good agreement and are within the permissible limits.
In this work, a dual-band compact MIMO antenna for sub-6 GHz 5G applications has been designed, simulated and implemented. Firstly, a single patch antenna was designed and simulated, and its dimensions were adjusted to exhibit a dual band performance at 3.6 GHz and 5.9 GHz. A two-element MIMO structure was then designed with a defected ground structure, and the S-parameters were recorded. The results showed that the designed MIMO antenna exhibited multiband performance at the sub-6G frequency band with almost omnidirectional radiation pattern and acceptable gain. The achieved results are promising, making the proposed antenna a good candidate for 5G applications. The proposed antennas were fabricated, and their basic parameters such as return loss and radiation pattern were tested experimentally and compared with simulation results. An acceptable agreement was achieved between measurement and simulation results.
In this paper A capacitive coupled Dielectric Resonator Antenna (DRA) array with log periodic method is explored experimentally for X-band applications. The incidence free DRA series consists of seven rectangular Dielectric Resonators (DRs). For both DRA and MPA arrays, a series fed microstrip line was used. In this work, Log Periodic Microstrip Patch Antenna (LPMPA) and Log Periodic Dielectric Resonator Antenna (LPDRA) arrays have been designed and realized, and the performance characteristics such as return loss, VSWR, gain, and bandwidth are simulated and validated experimentally. The LPMPA antenna is in active state from 10.2 GHz to 12.9 GHz with a bandwidth of 2.7 GHz and a gain of 8.55 dB. The LPDRA antenna is in active state from 7.3589 GHz to 12.1060 GHz with an increased bandwidth of 4.7474 GHz and a gain value of 8. 53 dB. The corresponding performance characteristics are presented at the end.
In this article, an open T-shaped stub resonator-based compact microstrip low-pass filter (LPF) with low in-band insertion loss and wide attenuation band is proposed. The folded T-shaped stubs loaded with T-shaped open stubs are symmetrically embedded in the high impedance line of the microstrip structure. The proposed LPF operates at a cut-off frequency of 2.4 GHz, a roll-off factor (ROF) of 62 dB/GHz resonated up to -48.5 dB at the resonant frequency, and an insertion loss of 0.35 dB in the passband region. In the ground plane of the LPF, two dissimilar defected ground structures (DGS) are placed in the array to generate additional attenuation poles for enriching the performance of the stopband. The sixth harmonic suppression is achieved up to 14.6 GHz and relative stopband rejection of 144%. The EM simulated results show a well-matched behavior with the experimental ones. The proposed LPF can be used for Bluetooth, Wi-Fi (2400 MHz), and microwave oven (2450 MHz) applications.
In this paper, dual-band split ring monopole antenna structures for 5G sub-6 GHz and WLAN applications are proposed. The antenna structures are designed from a rectangular annular ring monopole antenna. A compact dual rectangular split ring monopole antenna is designed to operate over dual bands. The two split rings are connected through a common arm. The structure is optimized to provide S11 ≤ -10 dB over 3.3-3.6 GHz and 5.15-5.5 GHz for 5G and WLAN applications. In the second dual-band antenna, a slot is cut in one of the arms to form another closed rectangular ring to further reduce the dimensions of the antenna. This structure provides S11 ≤ -10 dB over 3.3-3.6 and 5.5-5.9 GHz for 5G, WLAN and V2X applications. The two bands can be easily controlled as the dimensions of two rings determine the resonant frequencies of the two bands, and one of the arms of a ring is unresponsive to lower band and affects upper band only. Both antennas offer nearly omnidirectional radiation patterns in both bands. The two prototype antennas are fabricated on a 0.17λ0×0.19λ0 and 0.15λ0×0.19λ0 FR4 substrate, where λ0 is the free-space wavelength corresponding to 3.3 GHz. The measured results agree with the simulated ones.
A new formulation for the finite-difference time-domain (FDTD) technique is presented, for nonlinear circuit components provided that their X-Parameter representations are known. Transient electric fields at specified locations within the FDTD simulation are updated based on the frequency domain behavior of a multi-port nonlinear device, using the X-Parameter behavioral model. The formulation is demonstrated through the simulation of a nonlinear common-emitter amplifier embedded in a microstrip circuit with X-Parameters calculated from SPICE simulation results. Agreement may be seen between the X-Parameter-based simulation results and those acquired using a lumped-element method.