Slotted Printed Monopole UWB Antennas with Tuneable Rejection Bands for WLAN/WiMAX and X-Band Coexistence

YesFour versions of the compact hexagonal-shaped monopole printed antennas for UWB applications are presented. The first proposed antenna has an impedance bandwidth of 127.48 % (3.1 GHz to 14 GHz), which satisfies the bandwidth for ultra-wideband communication systems. To reduce the foreseen co-channel interference with WLAN (5.2GHz) and X-Band systems (10GHz), the second and third antennas type were generated by embedding hexagonal slot on the top of the radiating patch. The integration of the half and full hexagonal slots created notched bands that potentially filtered out the sources of interference, but were static in nature. Therefore, a fourth antenna type with tuneable-notched bands was designed by adding a varactor diode at an appropriate location within the slot. The fourth antenna type is a dual-notch that was electronically and simultaneously tuned from 3.2GHz to 5.1GHz and from 7.25GHz up to 9.9GHz by varying the bias voltages across the varactor. The prototypes of the four antenna versions were successfully fabricated and tested. The measured results have good agreement with the simulated results.This work is carried out under the grant of the Fundacão para a Ciência e a Tecnologia (FCT - Portugal), with the reference number: SFRH / BPD / 95110 / 201

Introduction of CAA into a mathematics course for technology students to address a change in curriculum requirements

The mathematical requirements for engineering, science and technology students has been debated for many years and concern has been expressed about the mathematical preparedness of students entering higher education. This paper considers a mathematics course that has been specifically designed to address some of these issues for technology education students. It briefly chronicles the changes that have taken place over its lifetime and evaluates the introduction of Computer Assisted Assessment (CAA) into a course already being delivered using Computer Aided Learning (CAL). Benefits of CAA can be categorised into four main areas. 1. Educational – achieved by setting short, topic related, assessments, each of which has to be passed, thereby increasing curriculum coverage. 2. Students – by allowing them to complete assessments at their own pace removing the stress of the final examination. 3. Financial – increased income to the institution, by broadening access to the course. Improved retention rate due to self-paced learning. 4. Time – staff no longer required to set and mark exams. Most students preferred this method of assessment to traditional exams, because it increased confidence and reduced stress levels. Self-paced working, however, resulted in a minority of students not completing the tests by the deadline

Wireless and Satellite Systems, 7th International Conference, WiSATS 2015

NoThis book constitutes the proceedings of the 7th International Conference on Wireless and Satellite Services, WiSATS 2015, held in Bradford, UK, in July 2015. The conference was formerly known as the International Conference on Personal Satellite Services (PSATS) mainly covering topics in the satellite domain. As the scope of the conference widened to include wireless systems, the conference was renamed to WiSATS

Risk-based adaptive user authentication for mobile passenger ID devices for land/sea border control

New services and products are increasingly becoming integral parts of our daily lives rising our technological dependence, as well as our exposure to risks from cyber. Critical sectors such as transport are progressively depending on digital technologies to run their core operations and develop novel solutions to exploit the economic strengths of the European Union. However, despite the fact that the continuously increasing number of visitors, entering the European Union through land-border crossing points or seaports, brings tremendous economic benefits, novel border control solutions, such as mobile devices for passenger identification for land and sea border control, are essential to accurately identify passengers “on the fly” while ensuring their comfort. However, the highly confidential personal data managed by these devices makes them an attractive target for cyberattacks. Therefore, novel secure and usable user authentication mechanisms are required to increase the level of security of this kind of devices without interrupting border control activities. Towards this direction, we, firstly, discuss risk-based and adaptive authentication for mobile devices as a suitable approach to deal with the security vs. usability challenge. Besides that, a novel risk-based adaptive user authentication mechanism is proposed for mobile passenger identification devices used by border control officers at land and sea borders

Reconfigurable Microstrip Printed Patch Antenna for Future Cognitive Radio Applications

A family of compact microstrip antennas are presented targeting applications such as Long-Term Evolution (LTE), Wireless Local Area Networks (WLAN), Universal Mobile Telecommunications system (UMTS), Global System Mobile (GSM) and global positioning system (GPS). These antennas consist of a rectangular shaped structure printed over FR4 substrate. The antenna occupies a small volume of 70x54x1.6mm3. A 50-Ohm strip line was used to feed the proposed antennas. For miniaturization purposes, an I- shaped slot was inserted in the appropriate location on the radiator resulting in the second version (antenna with I-shaped slot). The integration of the slot helped towards shifting the resonant frequency downwards, which potentially created an additional resonant frequency to cover the WLAN2400MHz, but this resonant frequency is still static in nature. Thus, tuning mechanisms were introduced to tune the resonant frequency over a wide continuous frequency range. A lumped capacitor was firstly used as the tuning approach, in which its capacitance was varied from 0.5pF to 3pF, covering the frequency range from 2300MHz to 1500MHz. Secondly, the varactor diode was exploited to verify this; by changing the bias voltage across the varactor from 0.21V to 12.9V, the antenna operates over the targeted range from 1500MHz to 2300MHz. Both the simulated and measured results show a stable performance. The proposed antenna may be suitable for future cognitive radio system