Applied Computational Electromagnetics Society Journal (ACES)

A Novel Multibranch-Linear-Linear Basis Function Based Adaptive Accuracy Enhanced Method for MFIE and CFIE From Multiscale PEC Targets

2026-01-28T23:58:37+01:00

In this paper, we propose a novel Multibranch-Linear-Linear basis function based adaptive accuracy enhanced (MB-LLB-AAE) method to solve the scattering problem from multiscale perfect electric conductor (PEC) targets. The calculation accuracy of traditional magnetic-field integral equation (MFIE) and combined field integral equation (CFIE) is not as good as that of electric-field integral equation (EFIE) under the same mesh size. The proposal of MBLL basis function has solved the accuracy problem of MFIE and CFIE when calculating multiscale PEC targets to a certain extent. However, a MB-LL basis function has two unknowns on a common edge, thus generating a prohibitive computational cost when calculating multiscale targets. Based on this problem, we propose the novel MB-LLB-AAE method, which not only effectively reduces the consumption when calculating multiscale targets, but also maintains an accuracy similar to that of using the MB-LL basis function only. Several numerical examples prove the advantages of the proposed method.

An Efficient MMA-PMA-CBFM for Solving Partial Modification Electromagnetic Scattering Problems

2026-06-23T11:17:14+02:00

This paper proposes an efficient algorithm for analyzing electrically large targets after partial modification. After solving the original model using the characteristic basis function method (CBFM), the mesh modification algorithm (MMA) is employed to modify the mesh according to requirements. Subsequently, in the CBFM blocks, only the characteristic basis functions (CBFs) associated with the affected blocks need to be regenerated, and the corresponding data in the reduced matrix are updated to rapidly obtain the solution of the new model by using the partial modification algorithm (PMA). Numerical examples validate the accuracy and efficiency of the proposed method, demonstrating its potential for practical engineering applications.

Fast and Efficient Analysis of Electromagnetic Radiation from Radome Thermal Protective Enclosure-Antennas Structure

2026-03-31T21:26:51+02:00

In this paper, a novel hybrid method combining the full-wave integral equation and high-frequency approaches is proposed to assess the electromagnetic performance of the radome and thermal protective enclosure (TPE)-enclosed antenna (RTA) structure. By using the approximate equivalence principle twice, the basic difficulty in applying the previously proposed hybrid method to RTA structure is eliminated. The interactions between the antennas and TPE, as well as between the combined antenna-TPE system and the radome, are accounted for iteratively. Numerical results demonstrate that the proposed hybrid method computes the radiation patterns of RTAs with good accuracy and significantly higher efficiency compared to full-wave solutions.

Localized Plane Wave Approximation for Bodies of Revolution in Vegetation Scattering

2026-05-02T02:07:58+02:00

Large computational electromagnetic problems for scattering from forest canopies in L-band (1–2 GHz) typically require modeling trees by a collection of lossy, dielectric cylinders and disks using Multiple Body of Revolution (MBOR) scattering techniques. MBOR techniques are desired for their computational efficiency compared to the 3-D Method of Moments (MoM). Within the vegetation environment associated with forest canopy, BORs are weakly coupled and, thus, approximations may be made to improve computational efficiency of MBOR scattering. This paper develops an efficient method to calculate the scattered fields from a lossy, finite length, dielectric cylinder, illuminated by a small current source. A small current source is representative of those on an adjacent BOR in MBOR scatter. Computational solutions to this problem exist, but those solutions are complicated and computationally expensive. Using the proposed method, a BOR is discretized into a series of discs such that far field conditions are a function of BOR radius rather than BOR length. These field conditions define the Localized Plane Wave Approximation (LPWA), which provides foundation for a more system specific MBOR scattering methodology, where BORs are harmonically independent of each other. For LPWA validation, the LPWA is compared to both analytical and computational solutions. The approximation shows good agreement within the constraints of the underlying assumptions. Finally, the method improves computational efficiency by more than an order of magnitude.

Comparative Analysis of Microstrip Patch Antenna Performance on Various Dielectric Substrates

2026-05-08T10:21:29+02:00

Microstrip patch antennas (MSPAs) have gained significant popularity due to their compact size, ease of fabrication, low cost, lightweight construction, and compatibility with planar and non-planar surfaces. The aim is to identify the optimal substrate for a designed MSPA by comparing the performance of six different substrates. Accordingly, both rectangular MSPA and circular MSPA (CMSPA) have been developed and simulated by using six different substrates: FR4 Glass Epoxy, ROGERS DT5880, ROGERS 4003C, Teflon, Arlon AD300A, and Alumina with thickness of 1.6 mm and 1 mm. Rectangular and CMSPAs have been fabricated and measured to verify the effects of the substrates. The proposed antenna is designed to achieve resonance at the target frequency of 5.8 GHz. This study offers valuable insights into the performance of MSPAs with various substrates, thereby assisting researchers in selecting the most appropriate materials for their designs.

High Efficiency, Low-Power RF Energy Harvesting Tri-Band Rectenna for Mid-Band 5G and Wi-Fi 6E Applications

2026-04-17T03:47:58+02:00

In this paper, a new tri-band rectenna is presented for radio frequency energy harvesting (RFEH) deployment. The proposed RFEH system integrates two primary components: an antenna and a rectifier. First, the antenna consists of a CPW-fed circularly-shaped patch incorporating three slots. Each slot is strategically introduced to reject a specific band. Second, the rectifier circuit is structured to ensure an efficient RF-to-DC conversion over three bands. High efficiency peaks are achieved at 78%, 76%, and 60% respectively at 3 GHz, 4 GHz, and 6.5 GHz, under 5 dBm input power, with overall efficiency average exceeding 71%. Peak DC output voltages of 2.52 V, 2.47 V, and 2.20 V are obtained at the same frequencies under the same conditions. The results confirm that the proposed rectenna effectively spans both the 5G mid-band and Wi-Fi 6E band, enabling the simultaneous and reliable powering of low-power devices. Furthermore, the antenna exhibits high frequency repeatability, achieved through the independent tuning of each band via strategically integrated slots.

A Compact High Scanning Rate Leaky-Wave Antenna Based on Spoof Surface Plasmon Polaritons Transmission Line

2025-05-29T08:19:49+02:00

A leaky-wave antenna with wide scanning angle and high scanning rate based on spoof surface plasmon polaritons transmission line (SSPPs-TL) is proposed. A tilted unit structure is introduced to flexibly adjust the dispersion characteristics, which not only reduces the cut-off frequency of the antenna but also enhances the electric field confinement. In addition, in order to achieve faster beam scanning, a row of periodic metal patches are placed on one side of the SSPPs slow wave structure, while periodic modulation metal strips are introduced on the other side. The proposed design converts slow waves into fast waves while broadening the scanning angle, thereby increasing the scanning rate. The effectiveness of the proposed scheme has been verified by the designed SSPP leaky-wave antenna in this paper. The measured results demonstrate that the designed antenna achieves a total scanning range of 41^∘ to 30^∘ and a maximum gain of 9.31 dBi in the operating frequency band of 5.8–8.4 GHz. Moreover, this antenna features a low profile and a compact structure and can be applied in communication systems.

A Miniaturized Wilkinson Power Divider with Integrated Phase Shifter

2026-05-02T17:14:58+02:00

This paper reports the design of a compact Wilkinson power divider for use in modern wireless communication systems where circuit size is a critical constraint. The proposed design replaces the conventional quarter-wavelength transmission line with a compact phase-shifting section based on parallel-coupled microstrip lines, providing an impedance transformation factor of $\sqrt{2}$ for proper matching to a 50 $Ω$ system. The power divider is designed to operate at a center frequency of 3.0 GHz on an AD260 substrate, with the phase-shifting function directly integrated into the power-dividing network to reduce the overall circuit footprint. The fabricated prototype occupies an area of $15.367 \times 22.860 {mm}^{2}$ , corresponding to a size reduction of approximately 22% compared with a conventional Wilkinson power divider. Simulation results obtained using Advanced Design System (ADS) demonstrate strong agreement, with a return loss ( $S_{11}$ ) better than 15 dB and insertion losses ( $S_{21}$ and $S_{31}$ ) close to the ideal value of $- 3$ dB at the operating frequency. The fabricated prototype was characterized over the 2–6 GHz frequency range, demonstrating strong agreement with the simulated results. These results indicate that the proposed structure achieves effective power division with good impedance matching while maintaining a compact size, making it suitable for integration into compact RF and microwave front-end circuits.

Design of Wideband Filtering Power Divider with High Port Isolation Performance for RF Energy Harvesting

2026-05-18T18:42:00+02:00

This paper presents a novel wideband filtering power divider with designable bandwidth and high port isolation, developed for RF energy harvesting applications. Two classes of structures integrate different shared networks with impedance transformers in their filtering branches to realize Chebyshev transformer functions. This synthesis approach allows for precise control over the bandwidth and return loss ( $R L$ ). Furthermore, high isolation is achieved by incorporating two resistors between the two output ports. Measured results demonstrate a wide operating band 103.7%, and high isolation level better than 25 dB of the bandwidth.

A Fast LO Leakage Calibration Method for MIMO Transmitter

2026-05-31T15:42:34+02:00

Local oscillator (LO) leakage caused by in-phase/quadrature (I/Q) offsets severely degrades the performance of direct-conversion multiple-input multiple-output (MIMO) transmitters in 5G and emerging 6G systems. Existing LO leakage calibration methods often require many measurements or suffer from slow convergence, making them inefficient for multi-channel and multi-frequency applications. To address this challenge, this paper proposes a fast LO leakage calibration method based on Newton’s method. For each channel at each frequency point, the I/Q offset compensation values are determined from only nine groups of I/Q settings and the corresponding LO leakage measurements. Simulations and experiments on an 8-channel MIMO transmitter show that the proposed method achieves an average LO leakage suppression of $-$ 55.6 dBc while reducing the number of calibration samples by more than 95% compared with traditional methods, demonstrating its efficiency and practicality for large-scale MIMO transmitters in 5G and 6G communications.