22 documents found, page 1 of 3
A feasibility study on real-time concealed object detection in foliage using ST...
Duarte, Luís; Vala, Mário; Ribeiro, Carlos; Alves, Luis N.; Fernandes, Carlos A.; Caldeirinha, Rafael F. S.This paper reports on the first results of a Swept Time-Delay Cross Correlator (STDCC) based radar performance for the detection of concealed objects in a foliage. The real-time STDCC radar operating at 25 GHz with 500 MHz bandwidth detection capabilities is benchmarked together with a VNA technique using a central frequency of 11 GHz with 18 GHz bandwidth. A set of measurements were performed to assess the att...
Reconfigurable millimetre-wave RF front-end for radar and 5G applications
Duarte, Luís; Reis, João R.; Leonor, Nuno; Ribeiro, Carlos; Alves, Luis N.; Caldeirinha, Rafael F. S.This paper proposes a reconfigurable RF architecture to cope with radar applications in autonomous driving vehicles and the next generation of communications (5G). A radio front-end architecture operating at frequencies between 24 and 27.5 GHz to deliver a small form-factor design that could easily be changed and ease future improvements, has been developed. Based on X-microwave ecosystem, a fully reconfigurabl...
All-digital reconfigurable STDCC radar baseband implementation in FPGA
Duarte, Luís; Ribeiro, Carlos; Alves, Luís N.; Caldeirinha, Rafael F. S.This paper reports the architecture of an all-digital Swept Time-Delay Cross-Correlator (STDCC) baseband. Until recently, the sliding correlator technique has been mainly em-ployed for sounding the radio propagation channel. However, recent benchmarks have shown promising results in target detection context when compared to commercially available solutions. STDCC takes advantage of the sliding correlation prope...
3D Indoor Radio Coverage for 5G Planning: a Framework of Combining BIM with Ray...
Louro, João; Fernandes, Telmo Rui; Rodrigues, Hugo; Caldeirinha, Rafael F. S.This paper presents a framework to predict indoor radio wave coverage in buildings. Such method includes the capability to import BIM (Building Information Modelling) files that contain structured physical geometry and dimension data, including the material types that are of uttermost importance in evaluating their dielectric properties. Appropriated extraction of physical and dielectric attributes of the build...
STDCC radar at 24 GHz: first measurement trials
Ferreira Sardo, Andre; Reis, João R.; Duarte, Luis; Leonor, Nuno; Ribeiro, Carlos; Caldeirinha, Rafael F. S.This paper presents the first measurement trials for performance assessment of a real-time and high resolution monostatic radar operating at 24 GHz. The proposed real-time radar, which operates based on the sliding correlation of pseudo-noise (PN) sequences, provides a high time resolution better than 4 ns, useful for moving target identification (MTI) in the presence of highly dense clutter, under harsh enviro...
Metamaterial-inspired Flat-Antenna Design for 5G Small-cell Base-Stations Opera...
Reis, João R.; Fernandes, Telmo R.; Patrício Carreira Vala, Mário António; Caldeirinha, Rafael F. S.In this paper, a flat-beamsteering antenna for 5G applications is being presented. The antenna, designed to operate at 3.6 GHz (5G new radio (NR) frequency range 1 (FR1) band n78), presents a unique flat form factor which allows easy deployment and low visual impact in 5G dense scenarios. The antenna presents a multi-layer structure where a metamaterial inspired transmitarray enables the two-dimensional (2D) be...
Analysis of Radiowave Propagation in Forest Media Using the Parabolic Equation
Ramos, Glaucio L.; Pereira, Paulo T.; Leonor, Nuno; Caldeirinha, Rafael F. S.This paper presents preliminary results about path loss prediction in vegetation using the parabolic equation technique. The trees were modelled in a flat and a triangular format and their effect in the path loss was analysed. A real measurement scenario with trees was also modelled and compared with the PE simulation. The use of the parabolic equation method to study the path loss attenuation in forest environ...
Multi-Gigabit/s OFDM real-time based transceiver engine for emerging 5G MIMO sy...
Ribeiro, Carlos; Gomes, Rodolfo; Duarte, Luís; Hammoudeh, Akram; Caldeirinha, Rafael F. S.This paper presents a highly scalable multi-Gigabit/s Real-Time (RT) Wideband (WB) Orthogonal Frequency Division Multiplexing (OFDM) processing chain for 5G applications. It is aimed to significantly reduce the Hardware (HW) footprint of Multiple Input Multiple Output (MIMO) systems. In this context, implementation complexity results for MIMO configurations of 2 × 2, 4 × 4 and 8 × 8, enabled at sampling rates o...
A 2D ray-tracing based model for wave propagation through forests at micro-and ...
Leonor, Nuno R.; Sanchez, Manuel Garcia; Fernandes, Telmo; Caldeirinha, Rafael F. S.This paper proposes the extension of a 2-D ray-tracing-based model for radiowave propagation in the presence of trees and vegetation areas to include real-sized trees and outdoor forest scenarios. The original propagation model proved to be suitable to characterize the electromagnetic behavior in the presence of indoor tree formation scenarios, despite some limitations found when applied to real-sized trees. In...
A mm Wave solution to provide wireless Augmented Reality in classrooms
Gomes, Rodolfo; Sismeiro, Luis; Ribeiro, Carlos; Sanchez, Manuel G.; Hammoudeh, Akram; Caldeirinha, Rafael F. S.This paper presents a very high throughput wireless data transmission solution for Augmented Reality (AR) Head Mounted Devices (HMDs) in the 60 GHz band. Its feasibility is assessed in an Orthogonal Frequency Division Multiplexing (OFDM) downlink communication towards five User Equipment (UE) devices, placed at different locations inside an indoor classroom environment scenario. Key Performance Indicators (KPIs...