Multiband handset antenna with a parallel excitation of PIFA and slot radiators

A handset antenna technique combining a parallel excitation of a PIFA and a slot is presented. The number of frequency bands is given by the sum of bands given per each radiator which can be controlled independently. Component interaction (battery, display, and speaker) is analyzed to determine the best place to mitigate performance degradation. Finally, a concept featuring a small footprint (39 11 mm) and low profile (2 mm) is proposed for multiband operation.A handset antenna technique combining a parallel excitation of a PIFA and a slot is presented. The number of frequency bands is given by the sum of bands given per each radiator which can be controlled independently. Component interaction (battery, display, and speaker) is analyzed to determine the best place to mitigate performance degradation. Finally, a concept featuring a small footprint (39 11 mm) and low profile (2 mm) is proposed for multiband operation.Postprint (published version

A User Scheduling Scheme for Reducing Electromagnetic (EM) Emission in the Uplink of Mobile Communication Systems

The ubiquity and convergence of wireless communication services have contributed to an unprecedented popularity of mobile communications. Given that wireless communication systems operate on radiofrequency waves, the electromagnetic (EM) radiation exposure they generate is also unprecedented and, hence, this could have adverse health effects on both humans and animals according to the World Health Organization. In this paper, we propose a user scheduling/power allocation scheme to minimize the EM exposure of users subject to transmitting a target number of bits. Our user scheduling method is based on assigning priority levels to each user and the user with the lowest priority level is scheduled for transmission. Power allocation, on the other hand, is based on the water-filling approach over time by using the past channel gains of a user to compute its water level. Simulation results show that our proposed scheme performs much better than a spectral efficiency based scheme but has a higher EM emission in comparison with a non-practical ideal scheme

Design and performance study of pattern reconfigurable MIMO antennas for mobile smartphones

This paper presents compact pattern reconfigurable antennas for mobile handsets in MIMO configuration. Each antenna of the MIMO configuration being coupled fed monopole in meandered form is capable of covering several cellular frequency bands in the range of 1.75–2.67 GHz including 4G‐LTE, 2G‐GSM, 3G‐UMTS, and WLAN. The MIMO antennas are printed diagonally at the left and right no‐ground portions on the top layer of the substrate to enhance the isolation performance. The substrate used is FR‐4 with relative permittivity of 4.35 and loss tangent of 0.02. The volume of the substrate is 120 × 65 × 1.6 mm3 with each antenna occupying an area of 26.5 × 14.5 mm2. The pattern reconfigurability is achieved by connecting and disconnecting a 4.5 × 2 mm2 metallic strip using the p‐i‐n diode switch. The antennas are pattern reconfigurable in the frequency range of 1.9–2.1 GHz. The isolation achieved is better than 16 dB over all the frequency bands covered by each antenna. A prototype has been fabricated and tested. The simulated and measured results show a good performance of the MIMO antennas. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:148–156, 201

Measuring and filtering microwave radiations using frequency selective surface through energy saving glass

This thesis presents the results of our investigation into the measurement and filtering of microwave radiation, and the subsequent development of a microwave reduction solution for modern building architecture utilising Energy Saving Glass (ESG), in conjunction with Frequency Selective (FSS) surfaces through which useful signals can be filtered. In the investigation, radiation power density levels arising from the three common microwave sources (radio base stations, mobile phones, and microwave ovens) were measured, and the results were compared with the standards provided by the Australian Radiation Protection and Nuclear Safety Agency. For the radio base stations, the relationship between radiation intensity levels and the important location parameters at the measurement point, e.g., line of sight, distance and elevation, are discussed in detail. Our results show that locations having the same elevation level as the RBS receive higher level of radiation, compared to those locations not at the same level. Power density of the radiation from microwave ovens was measured at various distances and angles. The results indicate that most of the radiation is emitted through the main door of the ovens, with the doors normally being assembled utilising simple float glass. ESG was found to have desirable radiation attenuating characteristics, and was identified as an effective replacement for float glass in microwave oven doors. In our investigation of the third potentially hazardous source of microwave radiation, the mobile handset, measurements were carried out in order to analyse power density levels during both call and idle times. Our results confirm that some handsets do not change power level, while others use higher power to communicate with the base station during a call. It is our recommendation that the manufacturers label each handset with the specific transmission power level in order to provide users with the relevant information. The conclusions drawn from our investigations lead us to recommend that ESG be used in buildings close to RBS, so that the levels of unnecessary radiation are reduced. However, useful signals would still be transmitted by utilising the dual bandpass FSS filters designed as part of this work. We designed two distinct models of bandpass FSS filters on hard coated ESG. The first filter that we designed will block microwave signals coming from weather radar, personal communication devices, power transmission lines and emergency service radios, while transmitting useful UMTS and Wi-Fi signals; minimising the radiation impact. Only 7.30% of the coating area of the glass was removed to enable transmission in the U850 and U2100 frequency bands. The second design requires the removal of 12.35% of the coating area to enable transmission in the U800, U850, U1900 and U2100 frequency bands. Simulation results for the two designs show stable frequency responses for both TE and TM polarisations at normal and oblique incident angles, with attenuation\u27s below 10 dB within the passbands. Parametric studies on geometrical dimensions, substrate permittivity, and thickness help clarify the effects of these parameters upon the overall performance of FSS on hard coating ESG, and help the process of FSS design optimisation

A Study on EMF Exposure Assessments With Different Metrics for User Equipment Antennas at 6 and 10 GHz

User equipment (UE) needs to comply with regulations limiting the exposure of the human body to electromagnetic fields (EMFs). In this paper, three exposure metrics including specific absorption rate (SAR), incident power density, and absorbed power density are quantified for different UE antenna designs. The study is conducted for three antennas - planar dipole, inverted-F antenna (IFA), and planar inverted-F antenna (PIFA), at two frequencies - 6 and 10 GHz, and for evaluation distances from 4 to 10 mm, which are within or close to the antenna’s reactive near field. The exposure ratios of the metrics are quantified according to the relevant EMF limit values. For validation purposes, prototypes are fabricated, and SAR and incident power density are measured. The average difference between the numerical and experimental results is 0.4 dB for SAR and 0.9 dB for the incident power density, meaning that good agreement between simulations and measurements is obtained. The study provides valuable input for EMF as- sessment requirements and test methodologies for emerging technologies at or close to the transition frequency between different exposure metrics