IEEE Transactions on Antennas and Propagation

The rapid advancement of wireless communication technologies requires efficient, optically transparent devices that can support high performance while maintaining optical transparency. This paper presents an optically transparent reflectarray (RA) antenna, enhanced with frequency selective surface (FSS) and multi-resonance subwavelength elements based on fine metal lines (FMLs). FMLs, with a widt…

This paper addresses the single-frequency radio frequency imaging in the presence of multipath propagation, relevant to indoor sensing applications. The imaging is tackled in a 2-D scenario and formulated as a linearized electromagnetic inverse scattering problem under the Born approximation. Analytical ray-based and full-wave numerical models are exploited to evaluate the incident field and the …

Electrostatically actuated mesh reflectors are a promising technology for space-based sensing and communication antennas. Key advantages over current passive mesh reflectors include the ability to correct surface distortions (e.g., from manufacturing defects and environmental disturbances) and to achieve beam steering and beam shaping via dynamic adjustment of the reflector surface. Implementatio…

Significant path loss at terahertz frequencies and the variation of antenna gain with distance pose key challenges for over-the-air (OTA) noise figure (NF) measurement of terahertz active integrated antennas (AIAs). This paper proposes a differential Y-factor OTA NF measurement method using a tunable photonic terahertz noise source with high excess noise ratio (ENR). The method eliminates the nee…

This paper presents a compact, high-efficiency, mode-switchable dual-band orbital angular momentum (OAM) antenna operating simultaneously at 5.8 and 28 GHz for integrated microwave and millimeter-wave (mm-wave) wireless systems. The proposed design features a single-layer, shared-aperture structure composed of two concentric uniform circular arrays (UCAs), each capable of generating OAM modes wit…

This paper proposes a novel design methodology for active frequency selective surfaces (AFSS) with switchable electromagnetic passband/stopband characteristics. The approach begins with filter circuit topology, providing a generalizable approach for designing single/dual-band AFSS with low insertion loss (IL) and high shielding efficiency (SE). First, we construct a filter circuit model by integr…

The phase-encoded linear sampling method (PE-LSM) is a qualitative inverse scattering technique for reconstructing the shapes of conducting targets. Previous work has demonstrated high-fidelity reconstructions using synthetic aperture data with a single transmitter and receiver, which is typically challenging for many inverse scattering approaches. In this paper, we propose a re-formulation of th…

The dilemma of optically transparent antennas, regardless of what material they are made from, has been the trade-off between transparency and antenna efficiency. This study examines the fundamental parameters that govern the two contradicting properties and presents optimized antenna designs for the two most basic antenna geometries: monopole and patch. For validation, monopoles and patches were…

This paper investigates a two-dimensional range-angle beampattern synthesis method for jammer suppression using a frequency diverse array (FDA) multiple-input multiple-output (MIMO) framework, where the transmit waveform, receive filter, and frequency increment are optimized. At the problem formulation stage, the objective function is chosen as the minimization of the squared error between the de…

This paper presents a multifunctional reflectarray antenna (MRA) featuring selective in-band switchable polarization and out-of-band radar cross-section (RCS) reduction. To mitigate the strong out-of-band reflections inherent in conventional reflectarray antennas, a frequency-selective rasorber is designed as the top-layer metasurface, providing a transmission passband for in-band operation and d…

In this work, a novel method for constructing low-fidelity models tailored for eigenanalysis-based multi-fidelity surrogate optimization frameworks is proposed. Namely, the proposed approach leverages reference eigenfunction expansions to solve a properly formulated boundary value problem (BVP), enabling the rapid computation of characteristic mode solutions for arbitrary structures. To ensure un…

A compact planar circularly polarized (CP) monopulse array antenna at the S-band based on an air-filled substrate integrated coaxial line (AF-SICL) feeding structure to suppress sidelobes in both sum and difference beam is proposed in this article. The AF-SICL and the stacked patch are tightly integrated to achieve subarray sequential rotation structure with unequally spaced elements, combined wi…

This work proposes an ultralow scattering frequency selective rasorber (FSR) with a wide passband. By integrating absorption and phase cancellation mechanisms, a radar cross section reduction (RCSR) of over 20 dB is achieved across a wide frequency range. First, using array theory, the reflection characteristics of the unit cell that achieves a 20 dB RCSR for the array are derived. The impact of …

This paper proposes a novel high-frequency scattering model for targets on complex rough surfaces. The core innovation is a local ray incidence-based technique that computes the reflection and multi-reflection components from targets and the coupling scattering components between targets and the background. This approach generates ray tubes exclusively from the target facet model. The background …

Programmable metasurfaces have emerged as a revolutionary technology with the flexibility in manipulating electromagnetic (EM) waves. They have attracted great interest in fields including wireless signal processing, radar, and satellite systems in recent years. Metasurface-based beamforming problem is widely solved by array synthesis techniques. However, traditional analytic and stochastic appro…

A novel method is proposed to measure dispersion and complex permittivity using densely and equally spaced skyrmion modes in a deep-subwavelength spoof localized surface plasmon (SLSP) resonator. The SLSP resonator is ultra-compact, with an electrical size of λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub>/89 or λg/27 (λ<sub xmlns:mml="http:…

Computing electromagnetic properties of large-scale finite periodic structures (LFPSs) via the multilevel fast multipole algorithm (MLFMA) often suffers from heavy time and memory consumption. The main reason is that complex structures and high-permittivity materials in LFPSs need dense meshes, leading to a prohibitively dense near-field interaction (NFI) matrix. To overcome this drawback, during…

This paper aims to address electromagnetic scattering problems in multiple bodies of revolution (MBoR) through a hybrid heterogeneous acceleration framework derived from equivalence principle algorithm (EPA). The computational workflow under EPA scheme is systematically divided into three dominant processes: matrix filling, LU-based direct solver, and iterative solver. To enhance matrix filling e…

A compact dual-band antenna element is presented that operates in the bands 0.617-0.894GHz (36.7% fractional bandwidth), and 1.69-2.4 GHz (34.7% fractional bandwidth). The dual-band antenna element consists of a low-band bowl-shaped antenna with a ring for the low-band and a high-band dipole antenna, placed in the center of the bowl. The ring is used to reduce the size of the dual-band antenna el…

This paper presents a broadband high-gain monopulse continuous transverse stub (CTS) array antenna based on gap waveguide technology, with its operating bandwidth covering the full W-band. The antenna comprises a novel hybrid beamformer and monopulse comparator network and a 16-element corporate-fed CTS array. A broadband sum and difference mode simultaneous excitation approach within the paralle…