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This paper presents a 10-Gb/s wireless link system that uses a 120-GHz-band sub-terahertz electro-magnetic waves. In the transmitter, photonic techniques are used for generation, modulation, and emission of the sub-THz signals, while the receiver is composed of all-electronic devices using InP-HEMTs
In recent years fractal geometries have been explored by various research groups around the world due to their purported potential of realizing multi-resonant antennas, possibly with smaller size and greater radiation efficiency. Most of the initial works in this direction were experimental approaches, but very recently the attention has been brought towards exploiting fractal features in antenna...
In this paper we describe the generation of terahertz radiation using different photonic techniques. The methods discussed here include surface emission from semiconductor surfaces in an external magnetic field as well as nonlinear generation in lithium niobate crystals, in particular, Cherenkov radiation and optical rectification in unpoled and poled lithium niobate (PPLN). Typical applications utilizing...
In this paper, the circular polarization microstrip antenna (CPMA) with fylfot-shaped structure was designed and fabricated by combining the bended and cross-shaped structure, using the feature that if the length of microstrip patch antenna (MPA) is fixed to miniaturize the center frequency of 1.575 GHz CPMA, currently being used in GPS system, width is shortened, and the feeding point moves to the...
A numerical procedure for calculating both the propagation constant and the field of modes of planar or channel waveguides with arbitrary refractive index profile is described. The procedure is based on the well-known variational expression for the propagation constant and uses as trial field an expansion in terms of Hermite-Gauss functions. The field parameters, i.e. the expansion coefficients and...
Frequency saturation of existing communication technologies and applications resulted in world-wide opening of new frequency bands for general public usage. For example, recently introduced IEEE 802.11a has provided additional channels in 5 GHz bands to ease congestion at 2.4 GHz. These new transmitters are typically certified to operate in laptop computers, PDAs or similar electronic accessories...
This study discusses the suitability of numerical methods as robust analysis and prediction tools regarding the RF performance of CAD derived mobile telecommunications equipment (MTE) such as mobile phones. The investigation was conducted using one of the latest commercial quad-band mobile phones and in addition included head and different hand models targeting a detailed assessment of in-use situations...
The complex permittivity of a sample of human skin is measured across the band 57 to 100 GHz using a free space technique. This data is used to fit a single term Cole-Cole function. The measured data is used in conjunction with a thermal model to determine the temperature rise on the skin surface exposed to millimetre wave signals of 100 Watts/m2 . This indicates a maximum temperature increase of...
A rapid development of optoelectronic components and optical communication systems has influenced education of optoelectronics at the Department of Radio Electronics of FEEC BUT. The structure of comprehensive optoelectronics curriculum at the Department of Radio Electronics and the way of laboratory works management are described. Special problems of teaching methods of optoelectronics are analysed...
A study about switched beam reflectarrays has been carried out as a task on the Spanish project ARCO, to know the possibilities of this kind of antenna. The study has demonstrated that is possible to have a control of the radiation pattern by using switches on the reflector surface, and were studied different configurations in order to simplify manufacturing process in big reflectarrays
This contribution briefly describes an eight-element array with enhanced bandwidth for GSM-UMTS bands. Another antenna with two electrical tilts obtained by a simple modification of the previous one is also presented. Both arrays have beam shaping and have been designed and manufactured in planar technology. The measurement results obtained for both antennas are presented. These measurements match...
The paper is focused on teaching "applied microwaves". Attention is turned to antennas, but the same structure in possible to apply for wave propagation, microwaves and EMC in their whole. The structure of the education is based on the theory followed by the computer simulations, the theoretical and engineering design and development, the measurement and final evaluation, which acts as the...
A method for synthesizing footprint patterns radiated by planar reflectors made of a large number of reflecting elements is presented. It is an extension to phase-only synthesis of a previous method that uses the modified Taylor expressions for circular apertures to provide good non-Phi-symmetric patterns. The possibility of selecting any kind of amplitude distribution allows the synthesis of patterns...
The paper describes the beam forming network that feeds linear antenna array of four monopoles above the ground plane and enables an electrical deflection of the array radiation pattern into the demanded direction. This solution is intended for practical teaching students of antenna and microwave courses
Human eye being unprotected by the layer of skin and bones is one of the most sensitive organs to EM radiation. The absorption of EM radiation is quantified in terms of SAR and to calculate the SAR the knowledge of complete electric field distribution inside the eye is necessary. In this paper the problem of distribution of near EM field inside an eye is considered as EM scattering problem. Human...
Many experimental studies gave different proofs on the pacemaker's susceptibility by ELF magnetic fields, nevertheless it's still difficult to trace currents and voltages that invade the pacemaker input stage, determining in this way anomalies in the implantable device. Luckily, modern computational resources, joined to the detailed conductivity models of human body, with a precision of the fraction...
In this paper, we extend the explicit analytical expression for the probability density function of a mobile channel signal composite envelope, during simultaneous fast Nakagami and slow (shadowing) fading. This enables analytically explicit assessment of the mobile channel transmission quality of service, in contrast to currently actual solving similar problems exclusively through numerical integration...
The canonical example of a one-ended indefinitely long conductor, intended as a filamentary source of static and dynamic fields, is examined. The final purpose is that of outlining the significant role which such a so far underestimated subject deserves to play as an engineering paradigm in the treatment of antennas and antenna-like structures, especially for EMC applications
This paper reviews recent progress of terahertz (THz) technology in Japan, and proposes new direction of the future strategy to open the research field in THz-technology-based applications in various fields such as THz sensing for bio, medical, medicine, security, and others, and THz wireless communication for over 10 Gbps applicable to short-distance-communication, hot-spots, and others
This work deals with an effective technique for estimating a proper number of voltage data external to the near-field measurement region in the recently developed planar wide-mesh scanning. It relies on the nonredundant sampling representations of the electromagnetic field and uses the singular value decomposition method to extrapolate the outside samples. This allows one to reduce in a significant...
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