Switchable Electromagnetic Bandgap Surface Wave Antenna

This paper presents a novel switchable electromagnetic bandgap surface wave antenna that can support both a surface wave and normal mode radiation for communications at 2.45 GHz. In the surface wave mode, the antenna has a monopole-like radiation pattern with a measured gain of 4.4 dBi at ±49° and a null on boresight. In the normal mode, the antenna operates like a back-fed microstrip patch antenna

An Independently Tunable Tri-band Antenna Design for Concurrent Multi-band Single Chain Radio Receivers

In this paper, a novel tunable tri-band antenna is presented for concurrent, multi-band, single chain radio receivers. The antenna is manufactured on a 50×100 mm FR4 printed circuit board (PCB), and is able to provide three concurrent, independently tunable operating bands covering a frequency range from 600 MHz to 2.7 GHz. The antenna performance is investigated for both numerical and experimental methods when using, first, varactor diodes and, second, digitally tunable capacitors (DTCs) to tune frequencies, which shows the antenna gain can be improved by up to 2.6 dBi by using DTCs. A hardware-in-the-loop test-bed provides a system level evaluation of the proposed antenna in a direct RF digitized, concurrent, tri-band radio receiver. By measuring the receiver’s error vector magnitude, we demonstrate sufficient isolation between concurrent bands achieving 30 MHz of aggregated bandwidth as well as strong resilience to adjacent blockers next to each band. The data reported in this article are available from the ORDA digital repository (https://doi.org/10.15131/shef.data.5346295)

Low-profile independently- and concurrently-tunable quad-band antenna for single chain sub-6GHz 5G new radio applications

This paper presents a quad-band frequency agile antenna, with independent and concurrent frequency tunability in each band, for a tunable, concurrent, quad-band single chain radio receiver for 5G New Radio (NR). More specifically, the antenna comprises of four planar slots etched in a ground plane and fed through a single microstrip feedline, without any impedance matching network. The structure is optimized to maximize isolation between the individual slots and their respective resonant frequencies. Furthermore, a novel high order harmonic suppression method is demonstrated, which controls the current distribution via creating a fictitious short circuit in the slot antenna-enabling the antenna to achieve a much wider tuning range. Numerical simulations are verified using experimental implementation and measurements, with good agreement observed. The four slots resonate around the 830 MHz, 1.8 GHz, 2.4 GHz and 3.4 GHz frequency bands, which are independently tuned (using a varactor diode in each slot) to achieve tuning ranges of approximately 64%, 66%, 27% and 33%, respectively. More importantly, the contiguous four bands covers a total frequency tuning from 0.6 to 3.6 GHz i.e. a tuning range of approximately 143%. Finally, far-field measurements are performed and the antenna is evaluated in over-the-air testbed (quad-band radio receiver), which measures the Error Vector Magnitude performance for the individual channels. Good performance is observed, confirming acceptable isolation performance between the four bands. The data reported in this paper is available, from ORDA-The University of Sheffield Research Data Catalogue and Repository, at https://doi.org/10.15131/shef.data.11219000.v1

Concurrent, Multi-band, Single-Chain Radio Receiver for High Data-Rate HetNets

A concurrent, tunable, triple-band, single chain radio receiver for 5G radio access networks is presented and its performance is evaluated in a hardware-in-the-loop test-bed. The test-bed emulates a 5G heterogeneous network supporting three independently tunable, wideband, simultaneous connections over a frequency range from 600 MHz to 2.7 GHz. The single chain receiver is able to achieve an aggregate bandwidth of 93.75 MHz, 31.25 MHz per band, and a net data rate of 187.5 Mbit/s through the use of single-carrier QPSK transmissions. The receiver demonstrate sufficient isolation between the concurrent transmissions as well as strong resilience to adjacent blockers through the use of a small guard band

Tunable, Concurrent Multiband, Single Chain Radio Architecture for Low Energy 5G-RANs

This invited paper considers a key next step in the design of radio architectures aimed at supporting low energy consumption in 5G heterogeneous radio access networks. State-of-the-art mobile radios usually require one RF transceiver per standard, each working separately at any given time. Software defined radios, while spanning a wide range of standards and frequency bands, also work separately at any specific time. In 5G radio access networks, where continuous, multiband connectivity is envisaged, this conventional radio architecture results in high network power consumption. In this paper, we propose the novel concept of a concurrent multiband frequency-agile radio (CM-FARAD) architecture, which simultaneously supports multiple standards and frequency bands using a single, tunable transceiver. We discuss the subsystem radio design approaches for enabling the CM-FARAD architecture, including antennas, power amplifiers, low noise amplifiers and analogue to digital converters. A working prototype of a dual-band CM-FARAD test-bed is also presented together with measured salient performance characteristics

Respiratory hospitalizations and respiratory syncytial virus prophylaxis in special populations

Palivizumab utilization, compliance, and outcomes were examined in infants with preexisting medical diseases within the Canadian Registry Database (CARESS) to aid in developing guidelines for potential “at-risk” infants in the future. Infants who received ≥1 dose of palivizumab during the 2006–2010 respiratory syncytial virus (RSV) seasons at 29 sites were recruited and utilization, compliance, and outcomes related to respiratory infection/illness (RI) events were collected monthly. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for premature infants ≤35 completed weeks gestational age (GA) who met standard approval criteria (group 1) compared to those with medical disorders (group 2) using Cox proportional hazards regression models with adjustment for potential confounding factors. Of 7,339 registry infants, 4,880 were in group 1 and 952 in group 2, which included those with Down syndrome (20.3%), upper airway anomalies (18.7%), pulmonary diseases (13.3%), and cystic fibrosis (12.3%). Group 2 were older at enrolment (10.2 ± 9.2 vs. 3.5 ± 3.1 months, p < 0.0005), had higher GA (35.9 ± 6.0 vs. 31.0 ± 5.4 weeks, p < 0.0005), and were less compliant with treatment intervals (69.4% vs. 72.6%, p = 0.048). A greater proportion of group 2 infants were hospitalized for RI (9.0% vs. 4.2%, p < 0.0005) and RSV (2.4% vs. 1.3%, p = 0.003) (unadjusted). Being in group 2 was associated with an increased risk of RI (HR = 2.0, 95%CI 1.5–2.5, p < 0.0005), but not RSV hospitalization (HR = 1.6, 95%CI 0.9–2.8, p = 0.106). In infants receiving palivizumab, those with underlying medical disorders, though not currently approved for prophylaxis, are at higher risk for RI events compared with preterm infants. However, risk of RSV hospitalizations is similar

Planar frequency-tunable quad-band antenna with independently controllable bands

A low-profile quad-band loaded-slot antenna with independently controllable frequency bands is presented in this paper. Four slots are carefully designed to generate four separate frequency resonances, which were independently tuned by employing varactor diodes in each slot. The proposed concept was simulated using a full-wave solver and validated through measurements. The results show that each of the four bands can be independently controlled by altering the bias voltage of the respective varactor diode. Overall, the measured frequency tuning of the 1st, 2nd, 3rd, and 4th bands were 450–750 MHz, 600–1200 MHz, 1200–2100 MHz and 2100–2700 MHz, respectively. The proposed antenna has good potential for applications in the concurrently tunable multiband radio systems, including 5G

Tuning range enhancement of a frequency-agile tri-band slot antenna

A low-profile tri-band slot antenna with enhanced tuning range is presented in this paper. Tri-band frequency agility is obtained using three varactor-loaded slots on a planar structure. The tuning range of the proposed antenna is enhanced by suppressing the higher-order resonance modes, especially by controlling the surface currents and creating a fictitious ground on the antenna. Following full-wave simulations, a prototype was developed and measured to validate the concept. Results show a tuning range from 600MHz to 3300MHz, which is a 600 MHz increase in the overall tuning range than previously reported