A monolithic geodesic H-plane horn array antenna that operates up to 170 GHz is achieved for the first time using a low-cost additive manufacturing (AM) technique. To reach high gain and symmetric beam, a truncated geodesic H-plane horn is used to obtain a narrow beam in the H-plane, while a 1 : 8 power divider built on parallel-plate waveguides is constructed to narrow the beam in the E-plane. A ray-tracing and physical-optics model is developed to facilitate the design, which is capable of computing the full radiation pattern, directivity, and gain (considering conductive losses) of geodesic H-plane horn array antennas with significant time efficiency and high degree of accuracy. The adopted metal-only laser powder-bed fusion AM technique is especially suitable for fast prototyping structures with intricate shapes at a low cost. However, special adaptations are still considered in the design to ensure a successful fabrication of the prototype operating at the D-band. The prototype maintains good frequency stability from 110 to 170 GHz with a return loss better than 10 dB and a symmetric pencil beam. The measured data show a maximum realized gain of 29 dBi, a maximum aperture efficiency of 67% (calculated using realized gain), and a maximum radiation efficiency of 86%.

This letter presents the design, fabrication, and experimental validation of a fully metallic 4 × 4 horn array antenna operating in the entire W -band (75 − 110 GHz). The array integrates a broadband 1 : 16 beamforming network and 16 pyramidal horn elements into a single monolithic structure. The beamforming network is composed of wideband twisters and E-plane power dividers, which are compatible with the metal-only additive manufacturing (AM) technique called laser powder-bed fusion (LPBF). The simulation and measurement results confirm a reflection coefficient below −12 dB in a 37.8% relative bandwidth, with a measured realized gain exceeding 21 dBi across the band. The array achieves an aperture efficiency of approximately 80% (calculated using realized gain) while maintaining sidelobe levels below −10 dB.

In this paper, we present a hybrid electromagnetic bandgap (EBG) structure based on a three-hole double-layer configuration. One layer of the EBG structure is positioned on the metal, while the other is on the printed circuit board (PCB). Dispersion analyses reveal that this new compact hybrid EBG could produce a wide stopband with high in-band attenuation. To evaluate its effectiveness in mitigating signal leakage at waveguide-to-PCB interfaces and its potential application in next-generation satellite communications (Sat-Corns), we designed two EBG structures specifically for low-Earth orbit and geosynchronous orbit SatCom hybrid array antennas within the E-band (71-86 GHz). The performance of these EBG structures is evaluated in the configuration of 4 × 4 hybrid arrays. We demonstrate that the proposed hybrid EBG structures can effectively enhance power transmission and significantly reduce mutual coupling in the waveguide-to-PCB interfaces.

This study introduces a ray-tracing and physical optics (RT-PO) model for multibeam phased array antennas (PAAs) integrated with dielectric lenses (DLs) to enhance wide-angle scanning capability. The model can accurately calculate radiation patterns with significantly reduced computational effort compared to full-wave simulations. Validation against CST simulations confirms the effectiveness of the proposed model. A DL is designed using the RT-PO model to increase the directivity of a dual beam PAA at ±70, achieving an improvement of about 0.6dB in directivity for both beams. The results have demonstrated the advantages of the DL-integrated multibeam PAA system.

This paper investigates the dispersion properties exhibited by three different three-dimensional (3D) periodic arrangements of metallic spheres with the following underlying lattices: simple cubic (sc), body-centered cubic (bcc) and face-centered cubic (fcc) lattice. Their Brillouin zone (BZ) and the corresponding irreducible BZ are introduced. We then examine the dispersion properties along the edges of their respective irreducible BZs. The findings demonstrate that structures with a non-sc arrangement and higher symmetry can improve design versatility while simultaneously reducing the anisotropy of the structure and broadening the operating frequency range. These advantages are beneficial for the development of 3D graded-index (GRIN) lenses.

We explore the dispersion properties of quasi-twist-symmetric structures using the multimode transfer-matrix method.Unlike periodic structures, these aperiodic structures do not have a translation periodicity because they are formed by translation and rotation by an angle s2π of a given subunit cell, being s an irrational number.In this work, this structure is exemplified by a pin-loaded coaxial transmission line, and it cannot be directly analyzed using commercial software due to the lack of periodicity.The results indicate that the dispersion diagrams of this kind twist-symmetric structures lie between the dispersion diagrams of periodic structures with similar rotation angles.

In this work, we examine the methodology for numerically computing the dispersion diagram of three-dimensional periodic structures using commercial electromagnetic simulators. Examples of periodic structures based on body-centered cubic, face-centered cubic, and monoclinic lattices are used to illustrate this methodology. We first outline the characteristics of these structures in both physical and reciprocal spaces from a theoretical point of view. On this basis, we provide a comprehensive explanation of how to adjust the setting in simulation software commonly used in microwave engineering to generate the dispersion diagrams of these structures. The appropriate simulation conditions are tabulated to serve as a further guide for other researchers. This study also explores the influence of the elements of the unit cell on the dispersion characteristics. Additionally, we evaluate and contrast the dispersion properties of identical periodic elements when having simple cubic, body-centered cubic, and face-centered cubic arrangements. We found that symmetries, such as those seen in body-centered cubic and face-centered cubic arrangements, can improve the isotropy and maintain low-dispersion characteristics over a wider frequency range. The monoclinic structure is also taken as an example to demonstrate that the reported analysis method can be applied to the dispersion analysis of other more complex noncubic lattices. Our findings offer useful information for the examination and engineering of three-dimensional periodic structures, which can be used to design microwave and antenna devices.

It is demonstrated that combining phased array antennas with dielectric lenses constitutes a suitable solution to increase the energy efficiency in next-generation communication systems. A dielectric lens is designed to increase the gain of an array antenna working in the 3GPP n257 band (26.5–29.5 GHz). The simulated results demonstrate that the dielectric lens increases the gain between 0.4 and 1.3 dB in a large scanning range from 0° to 60° at 28 GHz; meaning that the output RF power can be decreased by up to 26% for a same equivalent isotropic radiated power required from the base station.

In this article, we propose an innovative concept to realize flexible and cost-effective array antenna systems for next generation communication systems. The idea is to tailor the performance of an antenna array to different use case scenarios by applying a customized dielectric lens placed in front of the array. By combining a lens with an array, we can improve certain performance properties of the antenna system and adapt it for unique site locations and requirements. Moreover, the lens may also act as a radome, providing mechanical protection from environmental conditions. This study consists of exploring the possibilities of using a lens to increase the gain of the antenna in certain directions: scanning range close to broadside (from 0 degrees to 30 degrees), and extreme scanning ranges (from 60 degrees to 80 degrees).

Periodic structures are widely used in the design of microwave devices, such as filters and lenses [1, 2]. By altering the periodic element arrangements or their geometric parameters, the wave propagation properties through the structure can be manipulated to realize different functions. The dispersion diagram, which describes the relationship between wavevector components and frequency, is commonly employed to analyze the behavior of the phase/group velocities in periodic structures. In the engineering community, two-dimensional periodic structures have received significant attention, and structures arranged in rectangular and non-rectangular lattices have been investigated [3]. Additionally, three-dimensional (3D) periodic structures arranged in a simple cubic lattice have been studied, but limited efforts have been invested into other lattice arrangements possible in 3D periodic structures. In this contribution, we investigate the dispersion properties of 3D periodic structures with different lattice arrangements and provide detailed analysis steps. Specifically, the simple cubic, body-centered cubic, and face-centered cubic lattices are taken as examples to demonstrate our proposed analysis. Figure 1 illustrates these lattices and their respective smallest geometrical unit cells [4]. The setting of lattice points represents the underlying geometry of periodic structures. In this study, the connection between the lattices in the real and wavevector space is also shown. The smallest unit cell in the wavevector space that describes the full symmetry of the lattice is known as the Brillouin zone (BZ). By considering the symmetry of the smallest unit cell and the real periodic element, the BZ can be reduced further to the irreducible BZ to simplify the analysis. The dispersion properties of periodic structures can then be analyzed by checking the dispersion diagrams within the irreducible BZ, or even solely along its boundaries. We further compare the dispersion diagrams of the different periodic structures to illustrate some interesting properties of the structures. The extension of this study to more complex lattices is also discussed. The analysis and results shown here facilitate the study of 3D periodic structures and can be used in the antenna design process.