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Use of surface PIN (SPIN) diodes to reconfigure a slot fed dielectric resonator antenna (DRA) is demonstrated. A single SPIN diode is placed in the centre of the feeding slot to facilitate the ON-OFF switching mechanism, modulating the gain by ∼18dB.
This paper presents a new compact, wide band and high selective, metamaterial antenna for 2 GHz wireless applications. The proposed antenna is designed using metamaterial half wave length stepped impedance resonator. The antenna is centred at 2.1 GHz with 21% fractional bandwidth and wide/high selective harmonics rejection in the frequencies up to 4 GHz. The antenna's radiator length is 18 mm which...
Use of the body as a platform for wearable electronics is a topical subject. Omnidirectional antennas are thought to be useful for antennas in body area networks. However, the desirable properties of omnidirectional radiation patterns close to humans are severely diminished due to the lossy load nature of biological matter and high levels of scattering due to mismatch. To alleviate these problems...
In this paper modelling of specific on-body channels is conducted by using three different antenna types. Our goal is to investigate antennas performance in different on-body contexts and examine antennas propagation mechanisms. For this purpose, a measurement campaign is performed. Results will be provided in terms of channel gain, slow and fast fading modelling by performing statistical analysis...
Miniaturized, multi-material fibers represent a novel promising approach to integration of higher-level functionalities into textile mediums. In this work, we present novel ‘smart textile’ fabrics featuring multi-material fiber antennas compatible with existing 2.4GHz wireless communication networks. A sub-millimeter leaky coaxial cable fiber antenna is shown to be fully compatible with a textile...
A novel antenna including a glass plane for WBAN applications has been studied and proposed. The proposed monopole antenna consists of P-shaped radiator element, modified ground plane and a glass plane. The proposed antenna is able to cover from 3.1 to 5.1GHz. The antenna and model of human body have been simulated and compared by using CST and HFSS. Results have shown that the efficiency of the antenna...
This paper presents, for the first time, a coupled gap transmission line resonator based on dual composite right/left handed microstrip structure. This introduced topology proposes dual band with high selective sharp band pass response. The whole structure is designed using only one cell comprised using a shunt tank of interdigital capacitor and strip inductor, and series tank formed using patch capacitor...
In this paper, we investigate the effect of metallic eyewear frames on the reflection coefficient, the radiation pattern and the specific absorption rate (SAR) of 4G antennas integrated in eyewear. The antennas used in the study are Coupling Element type, with appropriate matching networks to cover simultaneously the 700–960MHz and 1.7–2.7GHz frequency bands. Two different antenna locations are evaluated:...
In this work, a reconfigurable radiation pattern metamaterial-inspired antenna is proposed. The structure consists of simple split resonator (SRR) loaded with two open circuits and introduced into the near field region of a monopole antenna. Two configurations are studied by considering the state of the open circuits. Simulated results show that the structure can change its beam direction by controlling...
In this paper the parasitic effects from the feed and termination on the far-field pattern of two types of leaky-wave antenna (LWA) based on Half-Mode Substrate-Integrated Waveguide (HMSIW) are thoroughly investigated. It is shown that the ripples observed on the radiation patterns originate from the discontinuities in the aperture field distribution, which typically appear at the feed and termination...
A closed-form solution for the electromagnetic scattering of a plane wave by a dielectric lossless or lossy prolate spheroid coating a concentric metallic sphere is studied in this work. The problem is solved using two independent methods: first, asymptotic expansions are applied on the spheroidal eigenvectors, allowing a closed-form solution which is valid for small eccentricities of the spheroid...
Natural spiral and helical antennas are discussed. The subsequent discussion is devoted to spiral and helical antennas designed based on metamaterial concepts, where the propagation phase constant is negative within a specific frequency range. These act as counter circularly polarized antennas.
Computationally efficient and reliable procedure for antenna design using electromagnetic (EM) simulation models is proposed. Our approach exploits trust-region-based gradient search and adjoint sensitivities for fast derivative evaluation. Derivative data allows for constructing the approximation model of the antenna responses. Computational cost of the design process can be further reduced by utilizing...
A miniaturized resonant antenna based on the −1st order resonance of the series-inductance-flexible (SIF) composite right/left-handed (CRLH) substrate integrated waveguide (SIW) is proposed in this paper. The SIF CRLH structure is realized by etching a transverse slot on the surface of the CRLH SIW unit cell with the series inductance flexibly changeable through varying the slot length. The −1st order...
Recently the effects of a frequency-dependent phase center on the time domain behavior of an antenna were described with an analytical expression for the antenna impulse response. This relation will be compared to the characteristics of a Logarithmic-Periodic Dipole Array (LPDA) within this paper. Similarities between the impulse response of an LPDA and a moving phase center will be identified. The...
This paper presents the development and construction of a low-cost passive phase conjugating array (PCA) antenna aiming the mitigation of multipath phenomena at 6 GHz. The implementation of the proposed array was performed on woven fiber glass substrate using both discrete and integrated circuits. Measurement results, obtained inside an anechoic chamber, from a 16-element PCA antenna under multipath...
The goal of the study presented in this paper is to investigate the performance of MIMO-WCDMA networks, where Principal Component Analysis (PCA) is employed at the reception. In this context, multipath propagation is exploited, as the individual received signals can be seen as different instances of the same physical phenomenon (i.e. transmission and reception of WCDMA sequences). As results indicate,...
This is the first report on novel mushroom type electromagnetic band gap (EBG) structures, consisting of fractal periodic elements, used for enhancing the gain and directionality of microstrip patch antennas. Using CST Microwave studio the performance of rectangular patch antenna has been examined on proposed fractal EBG substrates. It is found that fractal EBGs are more effective in suppressing surface...
This paper presents a compact implanted antenna operating at 0.915 GHz and 2.45 GHz. The antenna performance was investigated by simulation and validated with measurements. The antenna size is 1/25 λ at 915 MHz with a gain of −22.8 dB at 2.45 GHz and −27.3 dB at 915 MHz. The total efficiency achieved is −18.2 dB at 2.45 GHz and −21.8 dB dB at 915 MHz.
An evaluation of the present approach to the design of birdcage RF coils for RMI, based on periodic lumped circuit, has been performed. It appears that, for coils bigger than λ/6, a more accurate model is required, to reduce the trial-and-error tuning of the coil.
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