Search

An innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance bandwidth is enhanced by a factor of two and its gain on average by about 4 dB. Unlike conventional antennas, where the energy is dissipated in a resistive load, the technique proposed here significantly reduces losses. The antenna is excited from underneath the antenna by coupling RF energy from an open-circuited feedline through a slot in the ground-plane of the middle substrate layer. The feedline is shielded with another substrate layer which has a ground-plane on its opposite surface to mitigate the influence of the structure on which the antenna is mounted. The antenna has the dimensions 12.3 × 4.5 × 0.905 mm3 and operates across the 0.137–0.158 THz band corresponding to a fractional bandwidth of 14.23%. Over this frequency range the average measured gain and efficiency are 8.6 dBi and 77%, respectively. These characteristics makes the proposed antenna suitable for integration in sub-terahertz near-field electronic systems such as radio frequency identification (RFID) devices with high spatial resolution.

We present a compact wideband antenna operating in the 28 GHz and 38 GHz millimeter-wave spectrum. The proposed antenna is designed on the Rogers RT/duroid 5880 substrate. The proposed antenna has a simple geometry and compact dimensions of 17 mm × 12 mm × 0.79 mm. The antenna design is simulated using the ANSYS HFSS software. The features of the proposed antenna are also compared to similar designs from the literature, to demonstrate the potential of our antenna for use in the targeted frequency band. The results in the present paper indicate that our design is a good candidate for use in future wireless communication systems., QC 20230607

In this work, a novel millimeter-wave circularly polarized patch antenna is presented. The antenna offers wide bandwidth, high gain, compact size, simple geometry, low profile and wide axial ratio. The proposed antenna is designed on the top side of Rogers RT/duroid 6002 with thickness of 0.79mm. The analysis and numerical simulation of the proposed antenna is performed using the full-wave electromagnetic simulator, HFSS., QC 20230607

In this paper, a simple planar plow-shaped wideband antenna is presented for mm-wave 5G devices. The proposed antenna is designed on a thin substrate with an overall size of 10×12 mm2. The results show that the antenna offers 49.5% fractional bandwidth ranging from 22.2 GHz to 36.8 GHz. Moreover, the radiation efficiency of the antenna is >90% throughout the operating bandwidth, with a peak gain of 3.3 dBi. Through its simple structure and high performance characteristics, it can be observed that the proposed antenna can be termed as a potential candidate for future mm-wave 5G communication devices., QC 20230607

In this paper, a modified convex optimization technique is used for radiation pattern correction in a cylindrical-shaped conformal microstrip array antenna. The technique uses numerical simulations to optimize the amplitude and phase excitations, with the goal to decrease the Euclidean distance between the desired field pattern and the obtained (simulated/measured) field pattern while maintaining the main beam direction, null's location, and side lobe levels under control. Two prototypes of (Formula presented.) and (Formula presented.) conformal microstrip antenna array deformed from linear/planar structure to the prescribed cylindrical shape, with different radii of curvature, are studied to demonstrate the performance of the proposed technique. The proposed convex optimization model when applied to conformal antenna array possesses fast computing speed and high convergence accuracy for radiation pattern synthesis, which can be a valuable tool for engineering applications., QC 20230524

Surface Plasmon Polaritons (SPPs) operating in mid-infrared up to terahertz (THz) frequencies have been traditionally manufactured on expensive metals such as gold, silver, etc. However, such metals have poor surface confinement that limits the optical applications of SPPs. The invention of graphene is a breakthrough in plasmon-based devices in terms of design, fabrication and applications, thanks to its plasmonic wave distribution, low-cost prototyping and its inherent reconfigurability. In addition, recent advancements in plasmon-based metamaterials and metasurfaces led to the elimination of the past constraints on regular optical devices, opening a new door in THz devices and applications. This paper provides an operational perspective of the advanced graphene-based electromagnetic devices, with a focus on graphene enabled antennas, absorbers and sensors, analyzing the strengths and limitations of various design methodologies.

The proliferation of low-earth orbit (LEO) satellites and the LEO satellite internet will be a game-changer for the low-latency high-speed global internet. While this new generation of the satellite internet in conjunction with fifth generation network (5G) and sixth generation network (6G) enabled emerging technologies, such as precision farming and smart cities, it will bring new challenges, such as satellite collision, limited satellite lifespan, security concerns, and satellite brightness. This article discusses the satellite brightness caused by LEO constellations that potentially affect the ongoing astronomical studies. It reviews the underlying contributors to the satellite brightness as well as the state-of-the-art technologies proposed to mitigate this emerging challenge.

The paper presents the results of a novel 3-D shared aperture 3 × 3 matrix antenna-array for 26 GHz band 5 G wireless networks. Radiation elements constituting the array are hexagonal-shaped patches that are elevated above the common dielectric substrate by 3.35 mm and excited through a metallic rod of 0.4 mm diameter. The rod protrudes through the substrate of 0.8 mm thickness. It is shown that by isolating each radiating element in the array with a wall suppresses unwanted electromagnetic (EM) wave interactions, resulting in improvement in the antenna's impedance matching and radiation characteristics. Moreover, the results show that by embedding hexagonal-shaped slots in the patches improve the antenna's gain and radiation efficiency performance. The subwavelength length slots in the patches essentially transform the radiating elements to exhibit metasurface characteristics when the array is illuminated by EM-waves. The proposed array structure has an average gain and radiation efficiency of 20 dBi and 93%, respectively, across 24.0–28.4 GHz. The isolation between its radiation elements is greater than 22 dB. Compared to the unslotted array the improvement in isolation between radiating elements is greater than 11 dB, and the gain and efficiency are better than 10.5 dBi, and 25%, respectively. The compact array has a fractional bandwidth of 16% and a form factor of 20×20×3.35 mm3.

This paper presents an elegant yet straightforward design procedure for a compact rat-race coupler (RRC) with an extended harmonic suppression. The coupler's conventional \lambda /4 transmission lines (TLs) are replaced by a specialized TL that offers significant size reduction and harmonic elimination capabilities in the proposed approach. The design procedure is verified through the theoretical, circuit, and electromagnetic (EM) analyses, showing excellent agreement among different analyses and the measured results. The circuit and EM results show that the proposed TL replicates the same frequency behaviour of the conventional one at the design frequency of 1.8 GHz while enables harmonic suppression up to the 7 {\mathrm {th}} harmonic and a size reduction of 74%. According to the measured results, the RRC has a fractional bandwidth of 20%, with input insertion losses of around 0.2 dB and isolation level better than 35 dB. Furthermore, the total footprint of the proposed RRC is only 31.7 mm \times15.9 mm, corresponding to 0.28\,\,\lambda \times 0.14\,\,\lambda , where \lambda is the guided wavelength at 1.8 GHz.