Aeu-International Journal of Electronics and Communications最新文献

This paper presents a high-performance integrated monolithic ceramic dielectric waveguide (DW) filter featuring isosceles right-angled triangular (IRAT) resonators. The fabrication process of the filter involves embedding a specific number of blind holes (BHs) or through holes/slots (THs/TSs) in a hexagonal ceramic dielectric block, fully metallizing the dielectric surface, and forming a monolithic ceramic DW filter. To achieve magnetic coupling, four THs and a BH are introduced in the oblique edges of two IRAT resonators; alternatively, a TS and BH are introduced in their right-angled edges. Electrical coupling is realized through a deep BH on the right-angle side of the resonators. Two non-adjacent resonators initiate weak cross-coupling by cascading a T-shaped rectangular TS, shallow BHs, and deep BH, creating two transmission zeros (TZs) outside the band. The filter was fabricated to ensure theoretical correctness and process reliability. The measured results show an insertion loss between 0.5 – 1 dB and a return loss greater than 18 dB at a bandwidth of 3.4 – 3.6 GHz. Two steep out-of-band TZs occur at 3.26 GHz and 3.72 GHz, aligning with simulation results. Therefore, the filter not only exhibits excellent performance but is also convenient for mass production and manufacturing, offering significant potential for future applications in 5G / 6G communication base stations.

This paper presents an inverted F-shaped slotted broadband metasurface (MS)-based circularly polarized (CP) microstrip patch antenna. The host antenna comprises a truncated corner square patch with an inverted F-shaped slot, positioned on a 1.6 mm thick FR-4 substrate backed by ground plane. Concurrently, the MS layer is composed of a 4 × 4 square ring array, constructed on a separate 1.6 mm thick FR-4 substrate with net compact dimensions 0.54λ_o × 0.54λ_o × 0.027λ_o at 5.13 GHz, serving as a superstrate layer. The proposed antenna exhibits impressive performance, including a −10-dB impedance bandwidth from 4.40 GHz to 7.38 GHz as well as a 3-dB axial ratio (AR) bandwidth from 4.74 GHz to 5.52 GHz. Furthermore, at 5.13 GHz, it achieves a notable maximum radiation efficiency and realized gain of 85 % and 6.95 dBic respectively. Moreover, polarization of the antenna is observed as left-handed circularly polarized (LHCP). To validate the impedance response, the antenna’s equivalent circuit model has been sequentially developed, followed by the fabrication of a prototype. The measured results closely resemble with the simulated responses, indicating strong consistency between theory and experimental results. With its overall compact dimension of 0.65λ_o × 0.65λ_o × 0.027λ_o at 5.13 GHz, the proposed CP antenna is well-suited for 5G application.

This paper proposes a Doherty power amplifier (DPA) design method based on harmonic tuning and output combining network (OCN) optimization to extend the power back-off (PBO) range. Firstly, based on the optimal harmonic load impedance, a harmonic tuning optimization method is used to design the harmonic tuning network of the amplifiers, effectively improving the efficiency at saturation and PBO. Secondly, the fundamental output matching network and the post-matching network are considered as an OCN. The S-parameters of the OCN are calculated and utilized in the DPA design. To further expand the PBO range, the carrier load impedance at PBO is determined by considering the relationship between PBO range and reflection coefficient. Finally, a multi-objective evolutionary algorithm combined with the theory of solution set is used to optimize the OCN design, simplifying the design process of the output matching network. For verification, a high-efficiency DPA operating at 1.68 GHz with a large PBO range of 9.5 dB is designed and measured. Results indicate that the proposed DPA achieves a saturated output power greater than 44 dBm, with a peak efficiency of up to 75.2%. The efficiencies are 68.5% and 61.0% at 6 and 9.5 dB back-off powers, respectively.

Autonomous driving systems consist of vehicles that are able to communicate not only with other vehicles but also with entities in their environment, forming vehicle-to-everything (V2X) communication. However, the V2X applications have intense requirements posing a significant challenge to the telecommunication infrastructure. In this work, we consider two types of transmission, i.e. direct and indirect, and we utilize analytical traffic-engineering models with a view to conduct a performance analysis of a vehicular network that enables V2X communication. We additionally propose two resource management strategies in order to decrease the request rejection probability and consequently ensure enhanced communication conditions. The results reveal that the proposed resource management strategies constitute a strong asset for improving the system’s service provisioning capability.

This communication describes the development and assessment of the genuine Antipodal Vivaldi MIMO antenna operating in the ultra-wideband spectrum. FR4 dielectric material, which is widely used in antenna designs and has characteristic features, is selected and used as a dielectric. The single antenna component has two asymmetric flares obtained with different parameters, and it also has a rectangular ground plane combined with a bottom flare. In the MIMO configuration, the single-antenna is built in a rotationally orthogonal way to generate a four-port system with the dimensions of 45 × 45 × 1 mm³. The vertical and horizontal stubs are added to the ground flare to obtain a common ground structure and increase the performance of the novel antenna design. It has a bandwidth of approximately 9 GHz, which starts from 2.85 GHz and ends at 11.8 GHz. The antenna has reasonable gain values and a high isolation value between the elements in the operation range. In this context, it is foreseen that the developed structure can be utilized in distinct multiport UWB applications.

A reconfigurable ultra-wideband multimode terahertz OAM antenna array based on graphene and vanadium dioxide (VO₂) is presented in this paper. The uniform circular array (UCA) composed of circularly polarized (CP) antennas, which include a ring radiation patch, a parasitic patch, a perovskite substrate and an irregular VO₂ ground plane. The radiation patch is covered with a layer of graphene, by changing the chemical potential of graphene, the working bandwidth and axial ratio bandwidth of the antenna can be changed. By changing the phase state of VO₂ (metal state / insulation state) to control the working state of the antenna. The impedance bandwidth (IBW) of the CP antenna proposed is 115.09% (1.73–6.42 THz), the axial ratio bandwidth (ARBW) is 43.97% (2.36–3.69 THz). Using the CP antenna unit can simplify the complex feed network, and only feeding the equal amplitude and equal phase excitation can realize the vortex wave. Changing the number and rotation angle of the antenna unit can realize multimode vortex waves with the l= 0, ±1, ±2, ±3, the purity is approximately 1, respectively. The proposed UCA has excellent application prospect in the 6G communication.

This work presents an innovative Ultra-Wideband (UWB) antenna design inspired by metamaterials. The antenna features spatial and polarization diversity, operating efficiently over a broad frequency range of 3.3 to 13.84 GHz. The design consists of four orthogonally arranged monopoles in a co-planar setup, meticulously engineered with ground plane slots to mitigate mutual coupling effects. The antenna demonstrates resilient performance, maintaining mutual coupling isolation exceeding 14 dB between its radiating elements for most of the operating band.

Due to the rise in data-intensive applications, the von Neumann bottleneck is increasingly restricting modern computer architectures, resulting to latency and energy consumption. Addressing this challenge necessitates a CMOS-compatible solution with high energy efficiency and significant parallelism. Utilizing resistive switching components within a 1T1R crossbar array and the application of Stanford RRAM model, this paper suggests an original method for in-memory computing. Moreover, this work shows a new way to advance the popular RISC-V architecture by including memristive crossbar array. It does this by adding a custom instruction set, special hardware blocks, and the Scouting Logic Scheme. These modifications serve both as a comprehensive testbed for the memory system and a proof of concept for the future integration of memristors in computing architectures. The proposed design undergoes extensive testing and power analysis to validate its functionality and performance under various conditions. The results demonstrate significant improvements in computational efficiency and energy savings, highlighting the potential of memristor-based in-memory computing systems to overcome current architectural limitations.

A circuit design methodology for space applications is presented with an 8-bit resistive digital-to-analog converter (DAC) with XY addressing mode and BiCMOS buffer designed in IHP’s 130 nm SiGe BiCMOS technology (SG13S). The radiation tolerance of the implemented DAC is evaluated by circuit-level simulations particularly analyzing the radiation sensitivity of the DAC to analog single-event transients (ASETs). Radiation mitigation techniques are addressed. The total current consumption with a 3.3 V supply is 0.54 mA at a 1 MHz sampling frequency.

Despite the inherent transmission-range limitations of 60 GHz band, it has applications in a wide variety of fields, notably in rear occupant alert (ROA) systems for monitoring vehicle occupants in rear seats. In-vehicle monitoring radar systems commonly utilize microstrip patch antennas for transmitting and receiving electromagnetic waves, which generally suffer from limited bandwidth. Although various techniques such as stub matching and single and multi-section quarter-wave transformers can be employed to widen the bandwidth of a microstrip patch antenna, they lead to an overall increase in the antenna size. This study proposes a compact 3 × 1 series-fed patch array antenna designed for operation in 60 GHz band. The proposed compact antenna achieves impedance matching by employing a symmetrical inset structure on both the top and bottom of the patches, with different patch sizes and interelement spacings. The overall antenna dimensions, using the RO4830 substrate (ε_r = 3.23, tan δ = 0.0033), are 1.41 mm × 7.04 mm × 0.125 mm. The impedance bandwidth ranges from 60.95 to 66.73 GHz, and the maximum realized gain is 10.24 dBi at 62.5 GHz. The half-power beam-widths (HPBWs) are 33.96 degrees in the E-plane and 76.19 degrees in the H-plane at 62.5 GHz.