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In this paper, we extend the use of the multimodal variational method (MVM) to complex discontinuities. Classical MVM can't be applied to characterize complex discontinuities because the modal basis of such complex discontinuities is very difficult to find. To surmount this deficiency, we divide the complex aperture into elements where the electromagnetic (EM) wave can be easily expanded into first...
A beam switched loop antenna with eight symmetrical feeding ports is proposed for beam steering applications. The feeding ports when excited one by one generate eight steerable tilted beams capable of covering complete space in front of antenna. The return loss, polarisation and all other antenna parameters stays the same for all the eight feeding configurations. The directivity of the antenna for...
In this paper, concave rectangular and hexagonal patch configurations are simulated and optimized to reduce the mutual coupling and return loss in microstrip array antennas. An enhanced genetic algorithm is employed to minimize the design objectives through optimally computing the design parameters. However, the variation of design parameters leads to an undesirable central frequency shift. To avoid...
In this study, to achieve low profile dipole antenna having conical radiation pattern for satellite communications, we investigate the dipole antenna with EBG as a reflector. Firstly, the EBG structure is designed and simulated at 12.5 GHz. Next, radiation patterns of the dipole antenna arranged above the PEC and EBG are investigated and compared. Finally, mutual coupling effect of 2-element array...
In this work, a quantitative analysis of the electromagnetic fields in the vicinity of a patch and slot antenna, excited at 24 GHz, is conducted. The spatial decay of the electric and magnetic fields as well as the power density is evaluated on top of the substrate where other package/board components can be integrated. The results reveal that the spatial decay of the fields is qualitatively similar...
A circular microstrip patch antenna with a circular polarization (CP) sense using a slotted ground structure is proposed at 2.4 GHz. To generate a CP sense, an unequal cross-shaped slot on a ground plane is utilized as a perturbation. The proposed antenna has two input ports: one for a right-handed (RH) CP and the other one for a left-handed (LH) CP. This configuration has benefit of a separated input...
Friis transmission equation combined with Finite Difference in Time Domain (FDTD) method has been used to carry out investigation on Specific Absorption Rate (SAR) inside the human head model exposed to a 100 Watt GSM Base Station Antenna (BSA) at GSM-900 band. Maximum local SAR (MLSAR) has been calculated at 925 MHz, keeping distance between head and BSA in the range of 0.5 m to 5.0 m. The human...
In this paper, the radiation characteristics of frequency diversity array are concerned. With a set of CW signals of different frequencies transmitted simultaneously from the array, the transient field is examined by electromagnetic field simulation software. A periodically scanning beam is observed and the scanning speed is shown to be related to the frequency increment between two neighboring elements...
Increase of switching performances and integration design in modern electronic power devices make the compliance with the internal radiated behaviour more and more critical. This paper present the study and development of an integrated antenna module, called EM-Matrix, dedicated to measurement of the magnetic field in close vicinity of power circuits. First modelling works and experimental results...
A narrowband channel model (2.4 GHz to 2.5 GHz) for wireless sensors deployed over the external surfaces of a gas turbine engine is reported. The model is empirical and based on a series of transmission loss measurements over the surface of a gas turbine engine.
Dual-polarised microstrip flat panel antennas suited for radio-over-fibre (RoF) micro-cellular distribution systems are presented. The antenna units are intended to be low-cost and compact, provide reasonable gain, and serve the 4G-long term evolution (LTE) wireless band in a Manhattan scenario. A design study has been carried out to assess the effects of mutual coupling between the required sectors...
A novel fractal planar inverted F antenna (F-PIFA) based on the self affinity design is presented in this paper. The procedure for designing a Fractal Planar Inverted F Antenna is explained and the 2nd iteration of Sierpinski Carpet is chosen to use in mobile phones. The F-PIFA has a total dimension 27 mm ?? 27 mm are designed and optimized in order to receive GSM (global system for mobile communication)...
In this paper, we focus on multiple antenna-systems for portable UMTS devices. First, we perform a state-of-the art review of the best solutions developed all around the world. Then, we present all the UMTS multi-antenna systems designed at the LEAT of the University of Nice-Sophia Antipolis since 2004. We especially describe the neutralization technique dedicated to enhance the total efficiency of...
In an expanding number of worldwide clinical trials, conventional loop, dipole and square-patch antennas perform as external hyperthermia applicators for the adjunct treatment of cancer cells at superficial depths inside the human body. A smaller patch design in very close proximity with various phantom tissue models produces focused specific absorption rate (SAR) patterns without significant frequency...
In our modern world, there are a number of wireless communication systems and broadcasting services which must be integrated into vehicles. However, there is very limited space for a lot of gadgets, so the need for low-cost, compact but highly efficient antennas without the need of an amplifier is essential. This document describes a low-cost, small and rugged triple-service patch antenna which features...
Multifunction phased array radars have the potential of directing the electromagnetic radar beam without mechanically adjusting the antenna. Furthermore, the beam can be redirected instantaneously towards any location in space. Instantaneous, adaptive beam pointing enables the combination of functions such as tracking, surveillance, and weapon guidance each of which requires access to a shared antenna...
In this paper, the suitability of using a printed circuit board (PCB) microstrip patch receiving antenna for a novel application - RF energy harvesting to power a wireless soil sensor network deployed in an outdoor environment - is investigated. The performance of a conventional circular microstrip patch antenna using different microwave laminate substrates is evaluated in terms of return loss, radiation...
Variation of the path gain in on-body transmission channels is investigated in several realistic scenarios. Short-term and long-term fading statistics are investigated and non-stationarity of both the types of fading in indoor multipath environments is demonstrated. It was found that the short-term fading is best described by a Rician distribution with the K-value log-normally distributed, and a gamma...
Cognitive radio systems require antennas and microwave components to be actively tuned for different parts of the frequency spectrum. In this paper results of a study of three antenna tuning techniques are presented here. The first tunable antenna is a liquid crystal (LC) tuned microstrip patch antenna operating in the 2 GHz range. The simulated tuning range is 8% while the measurements showed a range...
This paper presents a novel polarisation dependent EBG (PDEBG) surface which makes use of sheet vias. The performance of the surface is analysed whilst varying the length, thickness and inclination of the vias. It is observed that the phase difference between the x-polarised and y-polarised component of the reflected wave can be controlled by varying these parameters. Furthermore, the surface exhibits...
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