Quad-band internal mobile phone antenna

A novel internal, quad-band antenna placed inside a ‘foldable’ type of Mobile Phone is presented. Its structure consists of a helical and a monopole element exciting two broad frequency bands. Using a simple matching circuit the proposed antenna covers several frequency bands including the Global System for Mobile Communication (890-960 MHz), Digital Communication System (1710-1880 MHz), Personal Communication System (1850-1990 MHz) and Universal Mobile Telecommunication System (1920-2170 MHz). It achieves a Voltage Standing Wave Ratio (VSWR) of less than three across all frequency bands with total radiation efficiency of more than 50%. Its novel design and structure occupies only 1.8 cm3 of volume making this antenna very small and very suitable for internal use inside mobile terminals

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

Analysis of Electric Field Strength for Planning Indoor 5.8 GHz Wireless Networks

Understanding radio channel path characteristics is a very important factor for ensuring quality of service and high data rates for indoor wireless communication systems. Obstacles such as human occupants, doors, walls, windows, etc. all have a significant impact on received signals strengths and will contribute to fading, multipath and shadowing effects. This paper studies the effects of changes within a building, such as opening and closing doors, and the movement and number of human occupants, on indoor signal propagation at 5.8 GHz. The effects of different obstacles inside the rooms are compared and highlight which has the most significant effect on the received electric field strength

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)

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

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

The lower airway microbiome in paediatric health and chronic disease

The advent of next generation sequencing has rapidly challenged the paediatric respiratory physician’s understanding of lung microbiology and the role of the lung microbiome in host health and disease. In particular, the role of “microbial key players” in paediatric respiratory disease is yet to be fully explained. Accurate profiling of the lung microbiome in children is challenging since the ability to obtain lower airway samples coupled with processing “low-biomass specimens” are both technically difficult. Many studies provide conflicting results. Early microbiota-host relationships may be predictive of the development of chronic respiratory disease but attempts to correlate lower airway microbiota in premature infants and risk of developing bronchopulmonary dysplasia (BPD) have produced mixed results. There are differences in lung microbiota in asthma and cystic fibrosis (CF). The increased abundance of oral taxa in the lungs may (or may not) promote disease processes in asthma and CF. In CF, correlation between microbiota diversity and respiratory decline is commonly observed. When one considers other pathogens beyond the bacterial kingdom, the contribution and interplay of fungi and viruses within the lung microbiome further increase complexity. Similarly, the interaction between microbial communities in different body sites, such as the gut-lung axis, and the influence of environmental factors, including diet, make the co-existence of host and microbes ever more complicated. Future, multi-omics approaches may help uncover novel microbiome-based biomarkers and therapeutic targets in respiratory disease and explain how we can live in harmony with our microbial companions

Microstrip Patch Antenna Array Mutual Coupling Reduction using Capacitive Loaded Miniaturized EBG

In this paper, a compact miniaturized EBG loaded with surface mounting capacitor has been developed. The dimension of the EBG patch with approximately λ/36 has been achieved with dimension highly dependent on the capacitor values. The integration of the capacitive loaded miniaturized EBG with a couple of microstrip patch antenna has reduced approximately 12dB mutual coupling within the elements at the antenna resonance frequency of 2.2GHz. The antenna E-plane gain has been improved for more than 2dB with 3dB reduction in side lobes when comparing the traditional array with the array integrated with EBG. The propagation characteristics and gain of the array have been analyzed using CST Microwave Studio (CST MWS). The measured results have shown good agreement with the simulated results. The miniaturized EBG will be very useful in minimizing the space within the array antenna especially for the MIMO applicatio

A Low Profile Switchable Pattern Directivity Antenna Using Circular Sectorized EBG

In this paper, a low profile patch antenna switchable radiation pattern diversity with total thickness of less than λ 0 /14 has been established.. The novel antenna structure is based on a conformal patch antenna operating in TM01 mode is integrated over an electromagnetic band gap (EBG) surface to provide a beam scanning antenna. The circular EBG elements are arranged in 6-sectors and the vias on each sector of the EBG are switched in and out to steer the beam into that sectors. The reflection coefficients for the antenna when the vias are switched remain stable. The simulation and experimentation results have shown that the antenna power pattern directed toward the sector, without via or the middle of sectors, without via. Overall a flexible low profile beam steering antenna is demonstrated. The antenna is designed for wireless network application especially to improve the system performance in multipath propagation environment. Furthermore, the low profile antenna makes it suitable to be used in vehicular applicatio