A novel quasi-twisted miniaturized wideband branch line coupler (BLC) is proposed. The design is based on bisecting the conventional microstrip line BLC transversely and folding bisected sections on double-layered substrates with a common ground plane in between. The input and output terminals, each with a length of λ_g/4, and the pair of quarter-wavelength horizontal parallel arms are converted into a Z-shaped meandered microstrip line in the designed structure. Conversely, the pair of quarter-wavelength vertical arms are halved into two lines and transformed into a periodically loaded slow-wave structure. The bisected parts of the BLC are placed on the opposite side of the doubled-layer substrate and connected through four vias passing through the common ground plane. This technique enabled a compact BLC size of 6.4 × 18 mm², which corresponds to a surface area miniaturization by ~50% as compared to the classical BLC size of 10 × 23 mm² at 6 GHz. Moreover, the attained relative bandwidth is 73.9% (4.6–10 GHz) for S11, S33, S21, and the phase difference between outputs (∠S21 − ∠S41). However, if a coupling parameter (S41) of up to −7.5 dB is considered, then the relative bandwidth reduces to 53.9% (4.6–10 GHz) for port 1 as the input. Similarly, for port 3 as the input, the obtained bandwidth is 75.8% (4.5–10 GHz) for S33, S11, S43, and the phase difference between outputs (∠S43 − ∠S23). Likewise, this bandwidth reduces to 56% (4.5–8 GHz) when a coupling parameter (S23) of up to −7.5 dB is considered. In contrast, the relative bandwidth for the ordinary BLC is 41% at the same resonant frequency. The circuit is constructed on a double-layered low-cost FR4 substrate with a relative permittivity of 4.3 and a loss tangent of 0.025. An isolation of −13 dB was realized in both S₁₃ and S₃₁ demonstrating an excellent performance. The transmission coefficients between input/output ports S₂₁, S₄₁, S₂₃, and S₄₃ are between −3.1 dB to −3.5 dB at a frequency of 6 GHz. Finally, the proposed BLC provides phase differences between output ports of 90.5° and 94.8° at a frequency of 6 GHz when the input ports 1 and 3 are excited, respectively. The presented design offers the potential of being utilized as a unit cell for building a Butler matrix (BM) for sub-6 GHz 5G beamforming networks.

This paper presents a novel 28 GHz circularly polarized rectangular dielectric-resonator antenna (DRA) array for millimeter-wave (mmWave) off-body applications. A feed network incorporating cross slots was utilized in the rectangular DRA design to realize circular polarization (CP). In terms of the free-space wavelength, λ_o, the DRA dimensions were (0.48λ_o × 0.48λ_o × 0.27λ_o) at 28 GHz. The antenna array was simulated by incorporating dielectric layers with parameters that are equivalent to those of the human body at the desired frequency of 28 GHz for off-body communications. Moreover, the precise alignment and assembly of the DRA, which pose major difficulties at mmWave frequencies, were achieved by outlining the DRA positions on the ground plane using a three-dimensional (3D) printer. The array configuration was fabricated and measured with excellent performance, realizing a measured impedance bandwidth of 29% in conjunction with an axial-ration (AR) bandwidth of 13% and a broadside gain of 13.7 dBic at 28 GHz.

The academic community increasingly advocates for a more inclusive research culture, prompting universities to actively foster diversity, equity, and accessibility. This inclusivity is crucial for meaningful participation and recognising diverse perspectives in academia. In response, we organised an interactive seminar and developed a board game for engineering postgraduate research (PGR) students to grasp the concept of inclusive research culture. The seminar facilitated open discussions, allowing students to share experiences and comprehend the significance of a supportive environment. Emphasising inclusivity's role in generating innovative outcomes, the seminar showcased its potential through interdisciplinary collaborations. Based on and modified from ‘Snakes and Ladders,’ the accompanying board game enhanced understanding by providing an immersive experience that encouraged teamwork and creative problem-solving. This approach effectively promotes an inclusive research culture among engineering PGR students, imparting insights into the importance of a diverse and supportive research environment. By embracing inclusivity, universities unlock the research community's full potential, inspiring future generations to contribute significantly to diverse research endeavours.

This paper presents a novel reconfigurable reflective surface capable of selective magnitude control at sub-6 GHz frequencies. Each unit cell integrates a low-power single-pole double-throw (SPDT) RF switch beneath the ground plane, providing two distinct impedance states that govern the reflection coefficient of the unit cell. The proposed configuration enables dynamic switching between reflective and absorptive modes at 5.50 GHz. A full system prototype comprising an 8 × 8 unit cells was fabricated and tested, the measured results exhibit good agreement with full-wave simulations, with the 1-bit (0°-180°) reflection phase control at 5.05 GHz and reflection magnitude switching between -2.4 dB and -26 dB at 5.50 GHz under TE-polarized excitation. In addition, various geometric coding patterns were explored and implemented to further assess the surface’s capability for a thinned reconfigurability and improved power efficiency. Three sets of ring-based surface configurations were investigated in detail, demonstrating that the surface is capable of selective magnitude control at both 5.05 GHz and 5.50 GHz under these pattern configurations. Specifically, these configurations enable quantized reflection magnitude control at 5.05 GHz, with an average step size of circa 5 dB. The results confirm the surface’s flexible reconfigurability and reveal that activating only 75% of the available switches achieves performance comparable to full-surface operation, effectively reducing control complexity and overall power consumption.

A new compact, wideband, millimeter-wave microstrip crossover—designed without vias—demonstrates effective performance with an insertion loss of 2 dB across a wide frequency range. For Path 1, the operational bandwidth spans 11 GHz (13–24 GHz), while for Path 2, it extends over 10 GHz (12–22 GHz). The overlapping bandwidth, maintaining the 2 dB insertion loss criterion, covers 9 GHz (13–22 GHz). The design introduces two transition mechanisms to achieve optimal scattering parameters for the crossover: a stair-shaped microstrip line (MST) to ground-backed coplanar waveguide (GCPW) for the initial crossed line (Path 1), and vertical coupling between microstrip and coplanar hourglass microstrip patches on a single-layer substrate for Path 2. This innovative approach ensures an insertion loss of approximately 1 dB for both paths across the bandwidth, with a slight increase beyond 20 GHz for Path 2 due to substrate losses. Both crossed lines maintain a return loss of 10 dB across the spectrum, with isolation of approximately 20 dB. This design presents a flat, compact, and via-less configuration, with physical dimensions measuring 6.5 mm × 7.6 mm. The proposed design exhibits excellent scattering parameters, which enhance the efficiency of phased array antenna systems in terms of power transfer between input and output ports, as well as improving isolation between different input ports in the feed network of these systems used in remote sensing. Consequently, this contributes to the increased sensitivity and accuracy of such systems.

In recent years, there has been a significant shift towards providing comprehensive support to university students for their professional development, transferable skills, and employability. Capstone projects play a pivotal role in bridging the gap between academic learning and practical application, equipping students to navigate the challenges of their future careers (Fung, 2017) . These projects often serve as a reflection of students' growth and development, with successful completion signifying the acquisition of essential skills and knowledge in their chosen field of study. This engineering education practice paper explores the latest developments in engineering capstone project coordination, tutoring, and assessment, with a specific focus on enhancing student wellbeing. These practices aim to equip students with greater resilience, improved employability, and stronger teamwork skills, essential in the dynamic and diverse field of engineering. The intervention showcased here represents a significant enhancement for the 2022-2023 academic year in reinforcing the structure of capstone projects within the Department of Electronic and Electrical Engineering at The University of Sheffield. Initial findings indicate improvements in student wellbeing and interpersonal skills due to well-structured tutoring support and clear module deliverables guidelines.