Search Results (60)

The conventional von Neumann architecture, constrained by the memory and power walls arising from the separation of storage and computation, faces significant limitations in computational efficiency and energy consumption. To address these challenges, this paper proposes a computing-in-memory (CiM) architecture based on a hybrid 2T-2C/4T-2C ferroelectric random-access memory (FRAM) array. The proposed architecture performs majority-based bitwise computation by simultaneously activating multiple word lines, enabling AND and OR operations in conventional 2T-2C FRAM cells. Selectively embedded 4T-2C FRAM cells further provide in-array inversion, extending the supported functions to NOT and functionally complete Boolean logic. The architecture also supports full-adder operations and stores input operands, intermediate data, and output results within the same FRAM subarray, thereby reducing data movement. Moreover, the architecture provides ADC-free bitwise computing with binary inputs and outputs, reducing peripheral-circuit overhead and power consumption. The internal computation, nevertheless, relies on analog charge sharing and differential sense-amplifier resolution. HSPICE simulations indicate PVT-evaluated sensing stability and computational efficiency under the evaluated conditions. The bit-line voltage difference reaches 337 mV under triple-row activation and 214 mV under quintuple-row activation, with the former being 5.2 times that of the reported DRAM implementation used for comparison. At 3.3 V, process–voltage–temperature (PVT) simulations show that the maximum deviation of ΔV from its mean value remains below 4.62% across the evaluated process corners and temperatures from −40 °C to 125 °C. Simulations of the 8 × 8 FRAM CiM compute-array circuit model yield an energy consumption of 1.94–3.46 pJ/bit and a calculation latency of 0.599–1.167 ns for the supported bitwise operations, corresponding to a 4.86×–5.90× reduction in energy consumption compared with the reported DDR3-based design. The architecture also supports parallel processing and mitigates data loss associated with destructive FRAM readout through an in-array replication mechanism. Finally, an 8 × 8 hybrid FRAM CiM prototype was fabricated in a 180 nm CMOS process as a physical implementation of the proposed hybrid architecture, and its basic array functionality was verified. Full article

The transition from electrical to optical interconnects, enabled by the adoption of co-packaged optics (CPO) in advanced processors, is accelerating the scale-up to high volumes and redefining wafer-level test requirements. As optical interfaces migrate closer to the compute die, an increasing share of functional characterization must occur at the probe, where stringent sub-micron alignment, the mechanical stability necessary to preserve optical coupling against dynamic disturbances, and opto-electrical co-validation introduce new technical challenges. Ensuring repeatable and precise fiber-array-unit (FAU) engagement at the wafer level is therefore essential to enable scalable manufacturing of photonic-enabled processors. This paper introduces the EclipsePhotonic probe card, which embeds the Eclipse Dynamic piezoelectric positioning mechanism into a standard vertical-needle probe head as a route toward six-degree-of-freedom FAU manipulation with nanometric positioning accuracy. This architecture is designed to support repeatable coupling to on-wafer photonic structures without requiring specialized probe-head designs, thereby reducing integration complexity and addressing alignment-related yield risks. The platform is also intended to support multi-site electrical and optical probing, providing a path toward parallel test execution once the corresponding layout, optical-routing, and validation constraints are satisfied. A core innovation of the platform is its embedded sensor network, which integrates low- and higher-frequency displacement sensors, relative displacement sensors, and temperature sensors around a microcontroller-based supervisor. The vibration sensor fulfills a dual operational role: it detects environmental and test-cell disturbances that may have influenced optical coupling, providing essential context for binning decisions or targeted retest, and it contributes to probe card lifecycle monitoring by ensuring that the mechanical signature of the probe card remains within a validated operational “swim lane” throughout its service life. Recently published characterization of the underlying Eclipse Dynamic alignment engine shows that, in the production-optimized high-speed regime with effective hysteresis compensation, the Fixed Gradient routine provides the best normalized trade-off among the evaluated routines, with a normalized alignment cost of 1.44 a.u., 95.8% convergence reliability, and 99.4% of the global maximum optical coupling. These values should be interpreted as inherited algorithmic benchmarking results rather than as absolute wall-clock performance of the fully integrated sensor-augmented platform. Full article

Rooftop bifacial photovoltaic (PV) performance depends on both the optical properties of the roof surface and the installation geometry. This simulation-based study assessed a planned rooftop PV installation on a school building in Brno, Czech Republic, using PV*SOL simulations and statistical post-processing in R. The principal dataset comprised 238 bifacial scenarios combining seven spatially distinct roof zones assigned nominal albedo values from 8% to 80%, 17 module tilts from 0° to 80°, and row spacings of 1.00 and 2.10 m. Because each nominal albedo was associated with a different physical roof zone, the results represent combined roof-zone, reflectance and geometry responses rather than the isolated causal effect of albedo. The highest annual specific yield was obtained in the roof-zone scenario assigned 70% nominal albedo. The maximum was 1296.60 kWh/kWp at 1.00 m spacing and 35° tilt and 1359.34 kWh/kWp at 2.10 m spacing and 50° tilt. Under the fixed 25° reference configuration, the bifacial system outperformed the matched monofacial reference in all seven scenarios, with bifacial gain ranging from 7.57% to 11.23%. An empirical response-surface model reproduced the complete simulation grid with adjusted $R^2=0.980$ and RMSE of 13.94 kWh/kWp. For the representative 6.0 kWp subarray, the maximum lifetime incremental avoided-emission difference relative to the matched 8% reference was 10.35 t CO₂. Within the predefined Monte Carlo ranges, the highest-ranked scenarios produced positive incremental net present value in all 5000 sampled combinations. The findings show that roof reflectance should be evaluated together with tilt, spacing and spatial roof context. They do not establish a universally optimal albedo or rooftop configuration. Full article

The exponential growth of AI-driven data traffic necessitates the evolution of Data Center Networks toward high bandwidths and sub-microsecond latency. While co-packaged optics (CPO) offer a pathway to reduced energy consumption and increased capacity, they introduce significant challenges in optical chip coupling and packaging complexity. This study explores monolithically integrated metasurfaces as an alternative for optical interfaces, potentially reducing the need for bulky external microlens arrays or extremely precise mechanical alignment. We design an amorphous silicon (a-Si) metasurface on a Silicon-On-Insulator (SOI) platform operating at 1310 nm. By spatially mapping nanopillar radii to satisfy a spherical phase profile, we achieved near-vertical beam emission with an emission angle of 0.88° focused at a focal length of 98.99 μm. Broadband characterization across a 20 nm band confirms stable focusing and a confined spot size with moderate roll-off toward the band edges. The sensitivity of the emission profile of the device to fabrication imperfections in pillar radius, height, and sidewall taper is quantified. The coupling to a polymer-based optical redistribution layer (ORDL) is also studied, and the corresponding modal analysis demonstrates a maximum coupling efficiency of 68.2% into an SU-8 polymer waveguide. Tolerance analysis results reveal deterioration of 0.9 dB and 0.4 dB for $\pm 0.6 \mathsf{\mu }\mathrm{m}$ horizontal and $\pm 1.5 \mathsf{\mu }\mathrm{m}$ vertical misalignment respectively, making the interface compatible with relaxed alignment assembly assumptions, although experimental packaging validation remains required. The methodology is further validated at 1550 nm, demonstrating its applicability across telecom bands. These results suggest that integrated metasurfaces may simplify the packaging stack and enhance density for next-generation CPO links by providing precise, on-chip wavefront manipulation. Full article

A Q-switched pulsed laser based on a coupled 7-core Yb-doped fiber with a cavity based on a fiber Bragg grating array has been demonstrated with a maximum energy of microsecond pulses up to 15 μJ at a 1 kHz repetition rate. The lasing spectrum is hybridized so that the laser line maxima of each core are nearly the same, having a negligible spread relative to each other, which is much lower than the wavelength shifts between individual FBGs in the cores. At the same time, the generated power is nearly the same in all the cores. However, when increasing the power beyond the stimulated Raman scattering threshold, the supermodes are destroyed so that the spectra in the cores become increasingly different and less stable, and the output power is mainly concentrated in one of the cores, whereas the pulse shortens significantly to a sub-microsecond duration (300 ns), with damped oscillations appearing at the beginning. The new regimes we demonstrated of the multicore fiber laser are promising for creating powerful pulsed radiation sources with a narrow spectrum. Full article

A broadband low-RCS circularly polarized (CP) antenna based on a bi-functional, single-layer polarization conversion metasurface (PCM) is proposed in this manuscript. The designed bi-functional PCM unit cell achieves a polarization conversion ratio (PCR) exceeding 90% across an ultra-wideband from 15.8 GHz to 31.2 GHz. According to the principle of phase cancellation, they are configured as a checkerboard array to reduce the monostatic RCS. A co-design strategy was employed for the design of the feeding structure. Analysis reveals that the slot has a significant impact on the subarray PCR, leading to multiple zeros that affect the RCS reduction. Notably, further analysis indicates that an appropriate feed structure can compensate for the zeros caused by the slot, achieving a balance between radiation performance and scattering performance. The array exhibits an RCS reduction exceeding 6 dB over a wide frequency band from 15.9 to 31.3 GHz and realizes a circularly polarized far-field pattern with an axial ratio (AR) below 0.5 from 16.3 to 17 GHz and a maximum gain of 10.38 dBi. Measured results of the antenna prototype match the simulations well. The proposed integrated design offers a viable solution for stealth platforms. Full article

This study proposes a high-isolation four-port wideband MIMO antenna array designed for sub-6 GHz 5G, IoT, and radar applications. The array is fabricated on a polycarbonate substrate with overall dimensions of 500 × 500 mm² (ε_r = 2.8, h = 1 mm). Four orthogonally arranged modified circular patches with triangular ground planes and optimized inter-element spacing (D₁ = 90 mm) are employed in the antenna’s design to achieve an impedance bandwidth of 0.7–7.0 GHz (Fractional Bandwidth (FBW) > 163.63%) with |S_ii| < −10 dB across all ports. The measurement results indicate that the inter-port isolation is better than 15 dB (worst-case) across the 0.7–7 GHz band, exceeding 25 dB over 63.5% of the bandwidth (with a peak of approximately 50 dB); the envelope correlation coefficient (ECC) is ultra-low (<0.008); the total active reflection coefficient (TARC) is less than −10 dB for primary multi-port excitations; the mean effective gain (MEG) is balanced (≈−3 dB); and the group delay is consistent (~0.5 ns). With a maximum realized gain of 10 dBi, the antenna exhibits omnidirectional radiation patterns, showing a significant correlation between the simulation (CST Microwave Studio) and measurement results. The proposed antenna is particularly well-suited for use in high-throughput sub-6 GHz 5G base stations and wideband wireless systems, offering superior port isolation through multi-mode resonance without the need for metamaterials and outperforming existing four-port designs. Full article

This paper presents a compact multi-beam dual-circularly polarized phased array receiving system operating in the 10.7–12.7 GHz frequency band is designed and implemented, which can generate eight reconfigurable receiving beams with independently configurable polarization modes and scanning directions for each beam. To improve the aperture utilization efficiency of the array and reduce the array size, the proposed phased array architecture adopts a “full-aperture multiplexing” beamforming method, where all beams share the same array aperture. For cost-effective phased array architecture with two-dimensional scalability, the array is divided into several identical receiving subarrays, with the control and power supply modules arranged beneath the array aperture. In addition, a heterogeneous integration scheme is introduced to realize high-density integration of various receiving functional chips, which reduces the overall array footprint by approximately 30% while maintaining the basic performance of the system gain-to-noise-temperature ratio (G/T). Meanwhile, different dielectric substrates are adopted to implement multi-level combining networks, optimizing the trade-off between overall efficiency and cost. To verify the feasibility of the proposed architecture, a prototype with a 16 × 16 array configuration is developed and tested. The measured results show that the array gain reduction is no more than 4 dB at a maximum scanning angle of 60°, and the G/T value of all beams in the boresight direction is not less than 0.9 dB/K at 11.7 GHz. The experimental results validate the effectiveness of the proposed multi-beam dual-circularly polarized phased array architecture in terms of engineering implementation and system performance. Full article

This paper presents the design and development of a reconfigurable circular array antenna capable of producing ten distinct radiation beams, intended for wireless systems in the sub-6 GHz frequency band. The antenna structure is based on four pentagon-shaped radiating elements arranged symmetrically around a central circular patch, which is excited through a coaxial feed. These radiating elements are linked by four circular segments, ensuring mutual coupling for effective operation. A systematic dimensional analysis has been conducted to optimize electromagnetic performance, resulting in a compact and efficient architecture. The beam reconfiguration is achieved through the control of four PIN diodes, which allow the main radiation beam to switch among ten different orientations in the azimuth plane. Specifically, the antenna supports eight directional states, oriented at 45° intervals, and two additional bidirectional states covering opposite directions. A prototype has been fabricated and experimentally validated, confirming the steering capability of ±40° in both the XZ and YZ planes. Performance evaluation shows a maximum gain of 9.29 dBi and efficiency levels ranging from 91% to 97%. Bandwidth varies across states, with 9.72% for S1–S7, 7.45% for S2–S8, and 4.61% for S9–S10. Overall, the proposed design demonstrates optimized bandwidth, gain, efficiency, and complete azimuthal coverage. Full article

The swift advancement of fifth-generation (5G) wireless technology brings forth a range of enhancements to address the increasing demand for data, the proliferation of smart devices, and the growth of the Internet of Things (IoT). This highly interconnected communication environment necessitates using multiple-input multiple-output (MIMO) systems to achieve adequate channel capacity. In this article, a 2-port MIMO system using two flipped parallel 1 × 2 arrays and a 2-port MIMO system using two opposite 1 × 4 arrays designed and fabricated antennas for 5G wireless communication in the sub-6 GHz band, are presented, overcoming the limitations of previous designs in gain, radiation efficiency and MIMO performance. The designed and fabricated single-element antenna features a circular microstrip patch design based on ROGER 5880 (RT5880) substrate, which has a thickness of 1.57 mm, a permittivity of 2.2, and a tangential loss of 0.0009. The 2-port MIMO of two 1 × 2 arrays and the 2-port MIMO of two 1 × 4 arrays have overall dimensions of 132 × 66 × 1.57 mm³ and 140 × 132 × 1.57 mm³, respectively. The MIMO of two 1 × 2 arrays and MIMO of two 1 × 4 arrays encompass maximum gains of 8.3 dBi and 10.9 dBi, respectively, with maximum radiation efficiency reaching 95% and 97.46%. High MIMO performance outcomes are observed for both the MIMO of two 1 × 2 arrays and the MIMO of two 1 × 4 arrays, with the channel capacity loss (CCL) ˂ 0.4 bit/s/Hz and ˂0.3 bit/s/Hz, respectively, an envelope correlation coefficient (ECC) ˂ 0.006 and ˂0.003, respectively, directivity gain (DG) about 10 dB, and a total active reflection coefficient (TARC) under −10 dB, ensuring impedance matching and effective mutual coupling among neighboring parameters, which confirms their effectiveness for 5G applications. The three fabricated antennas were experimentally tested and implemented using the MIMO Application Framework version 19.5 for 5G systems, demonstrating operational effectiveness in 5G applications. Full article

To meet the demands of real-time and high-definition (HD) image processing applications, denoising methods must be both computationally efficient and hardware friendly. Traditional image denoising techniques are typically simple, fast, and resource-efficient but often fall short in terms of denoising performance and adaptability. This paper proposes an adjustable-threshold denoising method along with a corresponding hardware implementation designed to support the real-time processing of large-array images commonly used in image signal processors (ISPs). The proposed technique employs a LeGall 5/3 wavelet with a row-transform structure and multilevel decomposition. A 2D Pyramid VisuShrink thresholding algorithm is introduced, where the threshold is derived from the median value of the HH sub-band using a multi-stage segmentation approach. To further optimize performance, a quantization strategy with fixed-point parameter design is applied to minimize storage requirements and computational errors. A specialized hardware architecture is developed to enable the real-time denoising of 4K images while adhering to constraints on speed and resource utilization. The architecture incorporates a finite state machine (FSM) and a reusable median calculation unit to efficiently share threshold-related storage and computational resources. The system is implemented and verified on an FPGA, achieving real-time performance at a maximum frequency of 230 MHz. It supports flexible input data formats with resolutions up to 4096×4096 pixels and 16-bit depth. Comprehensive comparisons with other real-time denoising methods demonstrate that the proposed approach consistently achieves better PSNR and SSIM across various noise levels and image sizes. In addition to delivering improved denoising accuracy, the hardware implementation offers advantages in processing speed and resource efficiency while supporting a wide range of large-array images. Full article

Three-dimensional hydro-acoustic imaging is a research hot spot in the underwater acoustic signal processing field, which has a wide range of application prospects in marine environmental resource surveying, seabed topography and geomorphological mapping, and underwater early warning and monitoring. To solve the problem that the resolution of the current imaging sonar reduces rapidly with increase in distance and a scanning gap exists in side-scan sonar, we designed a down-looking 3D-imaging sonar with a linear array structure. The imaging scheme adopts a time-domain spatial beam-forming method with the Back Projection (BP) algorithm as the core, and the formation of a virtual plane array can effectively improve the along-track resolution. To cope with the interference of the carrier motion error on the imaging, we proposed a high-precision sub-wavelength motion compensation method based on a real-time acoustic calibration system. Simulation and real data experiments show that the motion compensation method can effectively eliminate the influence of motion error and make the imaging energy more focused, leading to higher-quality acoustic images. Under equal average energy, the maximum superimposed sound intensity values in the imaging results increased by 20.75 dB and 6.57 dB, respectively, for simulation and real data. After motion compensation, the resolution of this imaging system reached 3 cm × 3 cm × 2.5 cm @ Depth = 17 m, TBP = 30 s · Hz. Full article

Ionoacoustic tomography exploits the acoustic signal generated by the fast energy deposition along the path of pulsed particle beams to reconstruct with sub-mm precision the dose deposition, with promising envisioned applications in hadron therapy treatment monitoring. State-of-the-art ionoacoustic detectors mainly rely on single-channel sensors and time-of-flight measurements to provide 1D localization of the maximum dose deposition at the so-called Bragg peak. This work investigates the design challenges of multichannel sensors for ionoacoustic tomography in terms of their ability to accurately reconstruct the dose deposition of a 200 MeV clinical proton beam, highlighting the impact of the number of channels in the array and their directivity. A complete acoustic model of the sensors and environment has been developed and used to find an optimum tradeoff between accuracy, evaluated numerically through the gamma index, and hardware complexity due to higher channel numbers, thus minimizing the system-level power consumption of the detector. Full article

Increasing array gains is one of the keys to improving underwater targets’ detection capabilities. This paper presents a high-gain approach for a vector hydrophone vertical array (VHVA) that combines white noise gain constraint (WNGC) with vector joint processing to preserve strong robustness and provide noticeable gains. Firstly, this approach treats the VHVA as four independent sub-arrays and achieves sub-array supergains by decorrelating noise using WNGC. The beam outputs of the four sub-arrays are then equated to a single-vector hydrophone, the combination gain of which is obtained by leveraging the strong signal correlation and the weak noise correlation between the sound pressure and the particle velocity. Lastly, the sub-array supergain and combination gain are superposed to provide the spatial gain of the VHVA. It is also summarized that low-frequency signals, coherent noise, accurate elevation-angle estimation, and stable phase differences are required for the VHVA to achieve supergain. The simulation and sea trial confirm that this approach can effectively boost the array gain. The maximum spatial gain in the experiment was increased by 9 dB at a range twice the sea’s depth while operating at a low frequency. This method shows enormous potential for improving the performance of deep-sea target detection. Full article

In the process of locating mixed far-field and near-field sources, sparse nonlinear arrays (SNAs) can achieve larger array apertures and higher degrees of freedom compared to traditional uniform linear arrays (ULAs) with the same number of sensors. This paper introduces a Modified Symmetric Nested Array (MSNA), which can automatically generate the optimal array structure with the maximum continuous lags for a given number of sensors. To effectively address mixed source localization, we designed an estimation algorithm based on high-order cumulants and the subarray partition method, applied to the MSNA. Firstly, a specialized fourth-order cumulant matrix, relevant only to Direction of Arrival (DOA) information, is constructed for the DOA estimation of mixed sources. Then, peak searching using the estimated DOA information enables the estimation of the distance parameters, effectively separating mixed sources. The algorithm has moderate computational complexity and provides high resolution and estimation accuracy. Numerical simulation results demonstrate that, with the same number of physical sensors, the proposed MSNA provides more continuous lags than existing arrays, offering higher degrees of freedom and estimation accuracy. Full article