Volume 75, Issue 11-12

This paper systematically analyzes the main link that imposes restrictions on the overall efficiency of the Microwave Wireless Power Transfer (MWPT) system–space transmission. Three typical transmission models of aperture transmission in the near-field area, radiation-focused transmission in the middle-field area, and Friis transmission in the far-field area of radiation were analyzed and calculated. Then, the applicable conditions and efficiency of three-models were compared. And the influence of antenna electrical parameters on the efficiency of the MWPT system was discussed. In the end, three typical space transmission models of aerial vehicles, satellites, and islands were studied. The influence of the medium on the transmission efficiency was emphatically analyzed. This paper aims to summarize the general laws of space transmission of microwave energy. Provide a theoretical reference for related scientific research and engineering practice.

With the rapid development of broadband carrier communication technology, the power line communication market is growing. However, the frequency band of power line communication overlaps with other radio services, mainly the High Frequency (HF) radio services. In addition, power line communication may have electromagnetic leakage in the open air. Large-scale power line communication system will give a much greater interference to some critical HF radio services. In this paper, the standards and researches relative to the power line communication system are reviewed. Based on existing studies, impact analysis which includes the impact probability and severity of the power line communication system on HF equipment is proposed. In addition, explicit explanations are provided. The proposed impact analysis methods are applied to simulations and evaluations. Numerical results demonstrate that a large-scale power line communication system will cause additional ambient noise, which affects the performance and reliability of HF equipment with a high probability.

This paper presents a novel structure of Hybrid Power Amplifier (HPA) to operate in two arbitrary classes of operation at two desirable frequencies. The proposed HPA is designed in concurrent F&F −1 classes, simultaneously for 5G application. Presented HPA can solve the harmonics interference problem for concurrent F and F −1 classes and also for any arbitrary class of operation in desired frequencies. The designed HPA operates at 1.5 GHz frequency in the F class mode, while operates at 2.1 GHz frequency in the F −1 class mode. A new method is presented by using two diplexers to provide two paths for signal in different frequencies. Two parallel paths are used at the output of the HPA circuit, so the proposed HPA can operate at two classes. Two diplexers are used in the HPA to make proper isolation between the designed paths. In design of the proposed HPA, according to the utilized diplexers, the amplifier can operate between two arbitrary classes of operation at desired frequencies without any specific switch. The measured drain efficiency (DE) and power added efficiency (PAE) parameters are 57 and 51%, respectively at 2.1 GHz, while measured DE and PAE are 64 and 54%, respectively at 1.5 GHz.

Analysis, design, and characterization of an E-band Variable Gain Amplifier (VGA) in SiGe BiCMOS commercial technology is presented. VGA topologies are compared in terms of their capability to contribute to receiver linearity and dynamic range. The proposed VGA is based on a Gilbert multiplier cell exploiting current cancellation to enhance control range and linearity. A 1 dB bandwidth ranging from 80 to 100 GHz, a 24 dB gain control range and a −11.5 dBm input 1 dB compression point have been measured.

In this paper, an efficient high-frequency method combining physical optics and shooting and bouncing rays is proposed to calculate the electromagnetic near-field scattering from the electrically large target (such as ship) in the near zone. In order to solve the mono-static and bi-static scattering problems, the local expansion technique based on the facets of target is presented to account for the near-field scattering, which has a singularity-free characteristic. And then the near-field contour-integral representation is introduced by refining the formulations in traditional far-field calculation to reduce the computational complexity. Therefore, this method is more straightforward to deal with the near-field scattering problem. Finally, some analyses on the near-field scattering characteristics and Doppler spectra of a surveillance ship in near zone are investigated by using the proposed method.

A single-layer miniaturized tri-band frequency selective surface (FSS) for bandstop filtering applications has been proposed in this work. The metallic layer with four-branched meandered pattern connected in the center is engraved on a dielectric FR-4 substrate. The three stopbands operating at 2.6, 5.6, and 7.1 GHz provides −10 dB bandwidth of 437, 447, and 552 MHz respectively. The size of the unit cell is 0.067 λ∘ × 0.067 λ∘, where λ∘ is the wavelength of the first resonance frequency. As a figure of merit, the symmetric FSS structure provides the advantage of polarization independence. The proposed compact FSS structure exhibits a stable angular response up to 60° in TE and TM mode. Moreover, measurements obtained from the fabricated prototype are compared with the simulated results and are found to be in close agreement.

In this paper, six-port MIMO antenna is presented for 5G mobile handsets. The proposed six-port antenna array is designed by making four L shaped monopole slots at four corners and two at the middle side edges of the ground plane which is printed on the backside of 0.8 mm thick FR4 substrate. High isolation (>−18 dB) between any pair of antenna elements is achieved without deploying dedicated isolation enhancing mechanisms. The antenna is working from 3.4–3.6 GHz (LTE Band 42) with 200 MHz bandwidth in the 2:1 VSWR (−10 dB impedance bandwidth). The proposed six-port MIMO antenna array is fabricated and measured. Significant radiation efficiency is obtained from 70 to 74 % in desired band of operation. Further, the MIMO parameters such as Envelope Correlation Co-efficient (ECC), Channel Capacity, Channel Capacity Loss (CLL) and Total Active Reflection Co-Efficient (TARC) are calculated. The robustness of the antenna is estimated by analyzing the user hand effects and Specific Absorption Rate (SAR). The measured results are well agreed with the simulated results.

This article discusses a 4-port micro-strip fed MIMO Antenna system with a triangular slot and an inverted L shape strip has been designed and analysed for both 2.3 GHz WiBro and Ultra-wide-band applications. The suggested antenna has been etched on a cost-effective epoxy (FR-4) substrate having ϵ r ${{\epsilon}}_{r}$  = 4.4 with an overall dimension of 45 × 45 × 1.6 mm 3 . Mutual coupling of −18 dB between the radiators has been obtained by orthogonal placement of radiators. From the simulated and practical results, the proposed compact MIMO system operates in frequency bands 2.26–2.42 GHz and 3.7–10.8 GHz respectively. The proposed small triangular MIMO system operates with an ECC less than 0.005 with an acceptable channel capacity loss <0.5 bits/s/Hz. Further, the diversity characteristics like DG, MEG, TARC, and group delay have been calculated and are presented in this paper.

In this paper, a circular Sierpinski shaped on-chip fractal antenna with defected ground structure (DGS) is presented for Ku-band applications. The fractal and defected ground structure are employed to achieve higher bandwidth for the entire Ku-band (12–18 GHz). The proposed on-chip antenna (OCA) with a footprint area of 4 π  mm 2 offers wide bandwidth of 7.22 GHz (11.94–19.13 GHz) with the resonating frequency of 15 GHz. At the resonating frequency, the designed antenna shows a peak gain of −19.76 dBi and a radiation efficiency of 55.6%. The co-polarization (CP) and cross-polarization (× P ) characteristics of the proposed OCA shows good isolation of 18.05 dBi and 17.44 dBi in the two principal planes with ϕ  = 0° and 90° cuts respectively. The measured result of the designed OCA prototype shows a good performance over the desired frequency band.

A compact rat-race ring coupler with modified T type capacitor loading is presented in this paper. Two variable parameters are added to the conventional T type capacitor loading structure, and adjusting these two parameters can control the position and width of harmonic suppression stop-band. The new coupler effective reduces the occupied area to 14.1% of the conventional one. The design is validated both by simulation and measurement.

In this paper, a metamaterial bandpass filter using Split Ring Resonators (SRR) is designed, analyzed, and developed for WLAN applications at 2.4 GHz frequency band. Here, metamaterial bandpass filters with and without Defected Ground Structure (DGS) are designed, analyzed and compared. The filter structure shows a considerable size reduction with 50% fractional bandwidth, quality factor of 2 and wide bandwidth. The simulation results of the proposed filters offered good insertion loss and return loss response. The filters have been modeled, fabricated and their performance has been evaluated using the Method Of Moment (MOM) based electromagnetic simulator IE3D. The dimensions of the proposed filter is 20 × 9 × 1.6 mm which is considerably reduced. The simulated and measured results projected that the proposed metamaterial filters are well suited for WLAN applications.

A microstrip planar lowpass filter with ultra-wide stopband up to 40 GHz is presented. The filter is designed based on four types of hexagonal-shaped resonators, producing multiple transmission zeroes and extending the stopband. The high-impedance transmission line is folded to make the circuit more compact and form the coupling gaps between the adjacent resonators. A pair of folded open stubs are added to enhance the cut-off rate. As a result, an ultra-wide stopband with 23rd-harmonic suppression has been attained. A demonstration filter has been designed and fabricated with 3 dB cut-off frequency of 1.70 GHz. The measured results show that the relative stop bandwidth of the low-pass filter (LPF) is 182% with suppression level of 25 dB, covering 1.85–40 GHz. The functional area size of the filter is 21.50 × 21.70 mm, which corresponds to 0.198 λ g  × 0.200 λ g ( λ g is the guided wavelength at 3 dB cut-off frequency).

A bandpass filter (BPF) of 2.24 GHz centre frequency and 44.6% fractional bandwidth, with a wide attenuation band is proposed in this article. The paper is focused on the analysis of complementary split ring resonator (CSRR) as a unit section of metamaterial and its application in designing of a bandpass filter. The proposed BPF structure consists of a stepped impedance stub-loaded resonator incorporated with the CSRR to suppress the harmonics to improve the attenuation band characteristics. A brief parametric study of the CSRR cell is done to demonstrate its role while suppressing the unwanted harmonics. The structure is fabricated, and measured to show a consistency with the IE3D simulated results.

The optical components based on photonic crystal had a wide range of applications fields these last years. In this work, we propose a configuration of photonic crystal structure of Channel Drop Filter (CDF). The proposed filter study by finite difference numerical method in the time domain FDTD makes it possible to ensure an average detected modal transmission rate of 95.30%, an average quality factor of order 3149.12 and a compact size of 144.65 μm 2 with high sensitivity to small variation of refractive index, period and radius of rods. Thus, we designed demultiplexer with four channels, which has a low average crosstalk of −30.73 dB. The transmission and the quality factor are 90.94% and 2221.13 respectively, with channel spacing 4.2 nm and a size of 405.6 μm 2 . These properties make our model of the proposed filter and demultiplexer well adapted for the realization of optical integrated circuit.

In this paper, a novel high power high selective and high- Q packaged dual band air suspended stripline notch filter is presented. The notch frequencies, at 2.4 and 3.5 GHz, were designed using defected suspended stripline (DSS). Moreover, the filter was packaged and shielded using perfect magnetic conductor (PMC). The DSS were designed using two frequency independent non-coupled cascaded U shape resonators. It has been proved that the filter attenuation has a sharp rejection characteristic (measured) at the two resonance frequencies (27 dB at 2.4 GHz) and (30 dB at 3.5 GHz) with Quality factor = (18). So, the sharp measured filter attenuation performance was further enhanced to become 38 dB at the two frequencies. The achieved results are discussed and confirmed using different circuit, 3D EM and experimental measurements. The designed filter can find many medium powers up to 20 kW applications .