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

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.

This work presents a multiple-input/multiple-output (MIMO) antenna consisting of dipoles with integrated baluns and a parasitic element to reduce mutual coupling, which can cover two frequency bands. The configuration of the decoupling element is determined by using an optimization algorithm. The algorithm takes nine physical dimensions of the decoupling element as input and adjusts them by minimizing a cost function. One of these decision variables (DVs) is the number of decoupling element’s stairs (steps), which is a discrete parameter. In its simple form, the antenna cannot obtain proper isolation in the low-frequency band, which has been solved by employing a decoupling structure in the middle of the antenna. The experimental results show that the antenna has impedance bandwidths of 1.95–3.50 GHz and 3.98–5.67 GHz, providing minimum isolation of 13.1 and 19.5 dB in the low- and high-frequency bands, respectively. The ECC value is lower than 0.0038, and the peak gains are equal to 4.4 and 5.21 dB for the low- and high-frequency bands. The main contribution of this work is the design of the decoupling element, which, considering the antenna’s characteristics, has improved the antenna’s isolation by 12.4 dB only in the center of the low-frequency band.

A compact ultralow-profile wideband and high-efficiency folded transmitarray antenna (FTA) is proposed in this letter. It consists of three parts: a top transmission surface (TS), a bottom reflection surface (RS), and an embedded compact planar feed. Using the principle of ray tracing and introducing additional phase compensation in the RS, the antenna profile can be significantly reduced, leading to a profile-to-diameter ratio (H/D) of only 0.13. Despite such an ultralow profile, the antenna overall performance still remains satisfactory. For design concept validation, a compact and ultralow-profile FTA is designed and prototyped. Measurement results demonstrate that the peak aperture efficiency of the FTA is 36%, with 1-dB/3-dB gain bandwidth of 10%/20%, respectively. These appealing characteristics make the proposed design very suitable for various high-gain applications where a low-profile and compact configuration is required.

In this paper, a compact dual-band antenna module has been developed, achieving significant isolation between the ports. The design integrates an open-edge slot antenna for the lower frequency band (5.15–7.1 GHz) with a 1 × 2 MIMO metasurface antenna for the mmWave frequency range (24.5–29.5 GHz), resulting in a high-performance, compact dual-band solution. The slot antenna is optimized for a reduced size configuration with enhanced bandwidth for lower frequencies, while the metasurface antenna delivers wider bandwidth and stable performance in the mmWave range with minimal mutual coupling and high efficiency. This makes the overall design highly effective for modern compact dual-band applications. The dual-band antenna module has dimensions of 20 × 16.5 × 0.99 mm (0.39λ₀ × 0.32λ₀ × 0.01λ₀, where λ₀ represents the free-space wavelength at 5.85 GHz). It achieves a measured peak gain of 3.8 dB for the lower band and 8.81 dB for the mmWave band. Additionally, the output of the mmWave antennas can be combined for higher gain or used in a MIMO configuration, enhancing channel capacity and communication reliability, which are critical for modern wireless systems.

Aiming at the electromagnetic compatibility testing requirements of slender equipment, this paper proposes a design scheme for a cylindrical reverberation chamber. Through numerical simulation, the lowest usable frequency and field uniformity of the cylindrical reverberation chamber were analyzed. The results show that the cylindrical reverberation chamber has good field uniformity when the frequency is greater than $$, meeting the stringent requirements of IEC 61000-4-21. Utilizing this cylindrical structure for the reverberation chamber can effectively reduce testing costs and improve testing efficiency and accuracy. This research provides a foundation for further optimization of cylindrical reverberation chamber design, and it is expected to become an important tool for effective electromagnetic compatibility testing of equipment.

The domain decomposition method (DDM) enables efficient simulation of electromagnetic problems in large-scale array antennas using full-wave methods on moderate hardware. This paper introduces and compares two nonoverlapping DDMs serving as preconditioners with outstanding simulation efficiency. The first method targets finite periodic array antennas by transforming a single array unit rather than explicitly modeling the entire array, effectively leveraging repetitive structures to significantly reduce memory usage and computation time. The second method applies to universal array antennas with arbitrary geometries, employing both planar and nonplanar mesh-based domain partitioning at subdomain interfaces for flexible modeling of complex arrays. To further enhance computational performance, we propose a parallel multilevel preconditioner based on the block Jacobi preconditioner, thereby accelerating the solution efficiency of subdomain matrix equations in both methods. Additionally, since the choice of domain partitioning method significantly impacts the computational efficiency of DDMs, we propose three different subdomain partitioning strategies. These strategies enable us to accelerate computations while expanding our capacity to simulate a wider variety of types of cases. We developed a fast electromagnetic radiation simulation tool utilizing these techniques. Simulations of exponentially tapered slot (Vivaldi) antenna arrays and antenna arrays with radomes demonstrate that our tool achieves accuracy comparable to commercial software, and notably, our tool outperforms commercial software in terms of the speed of iterative solutions.