International Journal of RF and Microwave Computer-Aided Engineering最新文献

A dual–dielectric resonator oscillator (DDRO) was previously introduced as a promising configuration for wireless power transfer (WPT), achieving a wireless power level of 13.07 dBm with a DC-to-RF efficiency of 19.50%. This work presents the design, simulation, and implementation of a single-port WPT system employing a parallel-feedback DDRO for increasing the output power level. The design incorporates a 7.5-GHz oscillator network featuring a class AB common-source power amplifier transistor integrated with a dielectric resonator (DR)–based WPT. By utilizing a parallel-feedback oscillator circuit, which enables efficient impedance matching through load-pull analysis and eliminates the need for a lossy termination at the end of the feed line, and optimizing the coupling structure for the transmitter DR, the output power level and the DC-to-RF conversion efficiency have been significantly improved. The implemented circuit delivers a measured wireless power level of 14.83 dBm, showing an improvement of approximately 2 dB, with a DC-to-RF efficiency of 36.85% at 7.5 GHz, while maintaining a transmission bandwidth of 150 MHz. This capability facilitates simultaneous transmission of both power and data over a single channel. The paper also presents an accurate model for design purposes and demonstrates validity of the model using our measurement results.

This paper introduces a compact dual-band band-pass filter using single multimode (TE₁₀₁, TE₁₀₂, TE₂₀₁, and TE₂₀₂) substrate-integrated waveguide (SIW) cavity with independent controllable fractional bandwidth (FBW) using metallic vias and slot perturbations. A via is placed at the center of the cavity, to shift the TE₁₀₁ mode towards the TE₁₀₂ mode which forms the Passband I with a center frequency (CF) of 16.2 GHz and a FBW of 1.71%. Two vias and slots are positioned and adjusted to shift the TE₂₀₁ mode and TE₂₀₂ mode, respectively, to achieve the Passband II with a CF of 19.1 GHz and an FBW of 3.09%. The measured insertion loss (IL) of the proposed filter is 1.8 dB for the Passband I and 1.9 dB for the Passband II.

In wireless telecommunication systems, the precise adjustment of the antenna direction has a direct effect on the quality of the received signal. In this article, a new routing algorithm is designed using the wireless energy harvesting (WEH) technology from electromagnetic waves to adjust the orientation of the receiver antenna. The algorithm is simulated for routing in TDD LTE cellular network at 2.35 GHz frequency. The proposed antenna in this article is a cross-dipole type with dual-polarization RHCP and LHCP, and its measured impedance bandwidths are 1.97–2.70 GHz at Port 1 and 1.96–2.72 GHz at Port 2. Also, 7.45 dBic peak gain and end-fire radiation capability of the proposed antenna are among the advantages of the automatic routing system. The proposed rectifier for WEH uses the voltage doubler technique. A new construction of microstrip elements has been used for the impedance matching network (IMN). The fabricated rectifier at 2.35 GHz can provide PCE = 52.8% at −0.5 dBm input power, which is suitable for WEH.

A printed MIMO antenna specifically designed for small satellite communication has been presented in this paper. The antenna is invented of two radiators resonating at millimeter-wave and constructed using Rogers’s RT duroid 5880. The design includes two identical octagonal patches with a diamond-shaped slot and having two quadrilateral notches. These elements are placed over a substrate and connected to a microstrip transmission line that embeds a quarter-wave transformer. To establish the effectiveness of the MIMO antenna being proposed, a comparative analysis is conducted between its simulated and experimental performance. Each radiator in the antenna setup includes partial ground, which forms the back layer of the substrate. The design is simulated on the CST tool, and measurements are conducted on a Rohde and Schwarz vector network analyzer. The obtained results show a favorable level of agreement with the simulated outcomes, validating the effectiveness of the proposed MIMO antenna. The antenna design offers exceptional features such as wide bandwidth, self-isolated, high gain, and a directional radiation pattern while also supporting a wide frequency band, making it an ideal choice for 28 GHz band applications. The performance of MIMO antennas in diversity can be determined using parameters such as envelope correlation coefficient (ECC), diversity gain (DG), and total active reflection coefficient (TARC). Satellite communication will be improved by implementing the suggested MIMO antenna through upgrading small satellite communication systems.

In the context of the rapid development of wireless body area network and ultra-wideband technology, this design puts forward a new structure of ultra-wideband flexible antenna. Its operating band is 1.22–8.82 GHz, with a maximum gain of 4.8 dBi. The antenna adopts a polyimide material with a relative dielectric constant of 3.5 and a thickness of 0.2 mm as the dielectric substrate. The overall size of the antenna is very small, measuring 0.15λ × 0.21λ at the lowest frequency of 1.22 GHz. In this paper, the influence of some antenna parameters on its performance, the influence of different bending conditions on the performance of the antenna, and the specific absorptivity of the antenna to the human body are discussed. In order to further explore the performance stability of the antenna, the performance of the antenna under right-angle bending is simulated and tested in this paper. Simulation results show that the antenna still has two frequency bands 1.22–2.58 GHz and 3.35–9.53 GHz under right-angle bending, which can still cover most of the commercial communication bands, and the measured results are in good agreement with the simulation results. Therefore, the antenna has strong adaptability and damage resistance and can be used in wearable equipment for military or emergency rescue.

This paper presents the design and performance analysis of a quad-band feed horn operating in the X, Ku, Ka, and W frequency bands, primarily targeting intersatellite communication and weather radar applications. The proposed feed horn employs a single-cavity structure with four standard rectangular feeding ports. To effectively improve isolation between closely spaced frequency bands, orthogonal feeding structures and low-pass filters are utilized. A prototype model of the antenna was fabricated and measured to validate the design’s effectiveness. Experimental results demonstrate that the designed feed achieves gains of 9.8, 12, 18.5, and 25.1 dBi at the operating frequencies of 9.4, 14.5, 35, and 94 GHz, respectively. Additionally, the voltage standing wave ratio (VSWR) is less than 1.4:1 at bandwidths greater than 1 GHz. These results indicate that the proposed feed horn is a promising candidate for future multifunctional radars and intersatellite communications.

M. Zhuo. “A Lumped-Element Directional Coupler for Bandwidth Enhancement, Impedance Matching, and Harmonic Suppressions,” International Journal of RF and Microwave Computer-Aided Engineering, vol. 2024, (2024). https://doi.org/10.1155/2024/6662753.

In the article titled “A Lumped-Element Directional Coupler for Bandwidth Enhancement, Impedance Matching, and Harmonic Suppressions,” there was an error in the referencing for Equations (2) and (3), which were incorrectly attributed to references [20] and [14]. These references should be corrected to [16] and [18], respectively.

We apologize for this error.

In this letter, an ultrawideband stacked structure metasurface is designed to minimize the backward RCS across a frequency range of 5–40 GHz. The stack structure design demonstrated a maximum RCS reduction at 19 GHz, achieving an impressive reduction of 18.11 dBsm compared to a PEC of the same dimensions. The proposed metasurface exhibits the capability to scatter incident plane waves in various directions under both normal and oblique incidence conditions. Additionally, the calculated quantized encoding phase can facilitate further RCS reductions of 3–6 dBsm within the frequency range of 8–25 GHz. Consequently, this work effectively designs and promotes research on low RCS metasurfaces across different frequencies.

In this work, we propose a physics-informed extreme learning machine (PIELM) method to identify the eigenmode field distributions of waveguides and transmission lines by solving Helmholtz partial differential equation (PDE) with initial and boundary conditions. A single-layer neural network architecture is adopted in PIELM, where the input layer parameters are initialized randomly. By embedding physics-informed constraints into the loss function, a system matrix equation can be established. Then, the output layer weights can be learned with the Moore–Penrose generalized inverse algorithm. Compared with physics-informed neural network (PINN), PIELM only uses a single-layer feedforward neural network and does not engage in an iterative optimization process utilizing backpropagation and gradient descent algorithms. As a result, the time spent on model training is reduced significantly, with the total process accelerated. Some numerical examples are presented to validate both accuracy and efficiency of PIELM method compared with PINN method in solving the eigenmode field distribution problem of waveguides and transmission lines.

This paper presents an improved design of a Ku-band power divider (PD) based on a substrate integrated waveguide (SIW) technology. The design is aimed at using the block upconverter (BUC) of the Ku-band satellite communication system. The PD has been developed to operate in the frequency range of 13.75–14.5 GHz for low-loss, good isolation, and good amplitude and phase imbalances for both power dividing and combining. To increase the isolation between output ports, TE₁₀₂ mode is selected to operate in the main cavity while the coupled cavity operates in the TE₁₀₁ mode. Low insertion loss of the PD can be achievable by determining Q factor of the SIW cavities. In addition, good phase and amplitude imbalances can also be obtained by making a suitable arrangement of the input and output ports. The measured results at the center frequency of 14.12 GHz exhibit an insertion loss of 1.3 dB, return loss of 16.9 dB, isolation of 16 dB, amplitude imbalance of 1.2 dB, and phase imbalance of 2.8°. The simulations are consistent with the measurements, validating the accuracy of the proposed method. The proposed PD can be a promising candidate for use in the BUC of the Ku-band satellite systems.