Dual band antenna for mobile terminals

The proposed antenna belongs to the area of integrated antennas with optimum features, and it is materialised in a metallic patch parallel to a Earth reference. The patch is preferably a rectangle but it can also have a trapezoidal shape, incorporating an only feeding pin and a short circuit which connect the antenna to the Earth reference.The antenna is approximately as long as a quarter of the highest resonance frequency’s wavelength, while the lowest resonance frequency is determined by a band-stop filter called spur-line, parallel to three out of four sides of the patch.The fact that the short circuit is placed in the furthest area from the slot or spur-line along the perimeter let us obtain a second resonance at a lower frequency than the original patch’s resonant frequency.The antenna has a metallic rectangular patch placed in a plane parallel to the Earth reference, which it is connected to by a metallic pin that acts as feeding point and another one as a short circuit. The patch is approximately as long as a quarter of the highest resonant frequency’s wavelength. The lowest resonant frequency is obtained from a spur band-stop filter parallel to three out of four sides of the patch.With this technological offer we try to collaborate with licence agreement and comercial agreement with technical assistance.Dual operation in small space. Low fabrication cost. Extension to other frequency bands.Diseño de estructuras radiantes para sistemas de telecomunicación.Diseño y fabricación de circuitos de microondas. Técnicas de medida de compatibilidad electromagnética

Radiocommunications, electromagnetism and microwave engineering research group (GIMRE)

The main activities, research lines and results of the Radiocommunications, Electromagnetism and Microwave Engineering Research Group (GIMRE) at the Technical University of Carthagene are portrayed. With just 8 years of activity, GIMRE is reaching maturity as a high-scientific achievement R&D group in the Region of Murcia, Spain

Dual band printed antenna

The invention consists of a dual band printed antenna planned to be implemented preferably in base stations of dual mobile telephony which use GSM and DCS-1800 systems, although other applications are not rejected.Similarly to the well-known printed antennas, the invented antenna has a dielectric substrate layer whose front side presents a printed patch. This patch is fed by the conventional microstrip line technique that is why the front side presents a microstrip line stretch reaching the patch. The dielectric layer’s backside presents an electric Earth reference. So far, this structure corresponds to the known as ‘printed antennas’.Optionally, the dielectric layer’s backside can include a metallic strip that will facilitate the adjustment corresponding to the bandwidth. The antenna’s microstrip line and the Earth reference can be connected to a SMA connector in order to facilitate feeding. This Earth reference, according to a preferential performance, has the same length as the microstrip line. In other performances, this reference could be placed perpendicular to the radiating patch enabling an omnidirectional configuration of the antenna. Depending on different performances and the sought radiation patterns, the dielectric layer’s backside could have a metallic plug joint to the Earth reference and/or a PTFE element (polytetrafluoroethylene, commonly known as Teflon). In that case, the PYFE element position has been planned to be either following the plug or between the plug and the Earth reference.The antenna has a dielectric substrate layer whose front side presents a patch antenna fed by a microstrip line stretch and whose back side presents an Earth reference. This patch has the shape of an isosceles triangle which connects one vertex to the stretch, while in parallel to the opposite side of the vertex, there is a slot in the patch operating like a filter. This enables a dual band operation wherein two resonant frequencies are controlled by the variation of the patch size and the slot length. The frequencies can be adjusted to values of 900 and 1800 MHz, facilitating the application of the antenna in dual mobile telephony with GSM and DCS-1800 systems. With this technological offer we try to collaborate with licence agreement and commercial agreement with technical assistance.Dual frequency operation. Low fabrication cost.Diseño de estructuras radiantes para sistemas de telecomunicación, Diseño y fabricación de circuitos de microondas,Diseño y fabricación de estructuras de calentamiento industrial por microondas,Técnicas de medida de compatibilidad electromagnética

Novel printed bow-tie antennas for dual-band dual-mode mobile handsets

The development of dual-band dual-mode D-AMPS/AMPS mobile handsets and radio stations has added pressure on GSM service providers to follow similar technology breakthroughs as a first step towards UMTS/FPLMTS. A frequency agile device accommodating both GSM standard frequency bands would serve more than 25 million GSM subscribers, with expectations as high as 100 millions subscribers by the year 2000. The complexity of the spectrum sharing between the two technologies and service generations may be alleviated by all terminal, system and network technologies. Several attempts to accomplish dual-band GSM/DCS 1800 operation on a single handset employing dual-band antenna concepts are introduced, and novel printed antenna elements developed at the Universidad Politécnica de Valencia are described.This work was supported by the Spanish Comisión Interministerial de Ciencia y Tecnologia, CICYT, under the TIC95-0983-C03-02 research project (Universidad Politécnica de Valencia)

Exposición de una cabeza humana a radiofrecuencia

En esta contribución, un plano coronal de cabeza humana es expuesto a 125 mW de potencia radiada por un dipolo de media onda a 1800 MHz. Se proporcionan tanto la TAE (Tasa de Absorción Específica) como los incrementos de temperatura asociados a la exposición electromagnética, para distintos escenarios. Se evalúa el efecto en el confort térmico de los procesos termorregulatorios humanos. Se presenta un importante efecto de adaptación entre el dipolo y la cabeza humana, así como al cráneo como protector del encéfalo ante tensiones térmicas debidas a exposición a campo EM. Como resultado del estudio, se podrían derivar restricciones básicas más precisas combinando los límites de TAE con la respuesta térmica asociada.Esta investigación ha sido financiada parcialmente por la Fundación Séneca, Agencia de Ciencia y Tecnología de la Región de Murcia, a través de una ayuda del Programa Séneca

CAD techniques for microwave circuits

In little more than 10 years computer-aided design (CAD) of microwave circuits has moved from dumb terminals on mainframe computers to PCs, and now to powerful RISC workstations. Commercial CAD software now integrates the various stages of microwave circuit design: schematic capture, simulation and layout. This paper reviews the different CAD packages that are available for microwave circuit design. The basic principles employed in the modelling of microstrip circuits are introduced and the reasons for the extensive use of frequency-domain simulations are explored. The developments in nonlinear, electromagnetic and system-level simulation methods are described.The authors would like to acknowledge the financial support of the Engineering and Physical Sciences Research Council, and the Comisidn Interministerial de Ciencia y Technologia (CICr?‘), Spain, under the project TIC95-0983-C03-02. We would like to thank Hewlett Packard, Barnard Microsystems, Sonnet Software, Optimization Systems Associates, Kimberley Communications Consultants and Ansoft Corporation for their generous educational discounting. The assistance of Dr. D. M. Brookbanks at GEC-Marconi Materials Technology Ltd. (Caswell) is gratefully acknowledged

Antena dual para terminales móviles.

Número de publicación: 2 185 463 Número de solicitud: 200002704Consiste en un parche metálico rectangular (1) situado en un plano paralelo al plano de masa, al que se conecta mediante un pin metálico que establece la alimentación (3) y el cortocircuito (4), siendo la longitud del parche (1) aproximadamente igual a un cuarto de la longitud de onda de la mayor de las frecuencias de resonancia (12/4), mientras que la menor de las frecuencias de resonancia se obtiene de un filtro de banda eliminada espolón (5) paralelo a tres de los cuatro lados del parche.Universidad Politécnica de Cartagen

Harmonic suppression in microstrip dual-mode ring-resonator bandpass filters

This paper introduces two new topologies for rejecting the harmonics in microstrip ring resonator filters. First one uses 50 Ω spur line filter structures placed at the input and output of the ring to suppress the first harmonic. Second topology incorporates low-pass structures into the ring for elimination of the harmonic

A new predictive neural architecture for solving temperature inverse problems in microwave-assisted drying processes

In this paper, a novel learning architecture based on neural networks is used for temperature inverse modeling in microwave-assisted drying processes. The proposed design combines the accuracy of the radial basis functions (RBF) and the algebraic capabilities of the matrix polynomial structures by using a two-level structure. This architecture is trained by temperature curves, TcðtÞ; previously generated by a validated drying model. The interconnection of the learning-based networks has enabled the finding of electric field (E) optimal values which provide the TcðtÞ curve that best fits a desired temperature target in a specific time slo

Emulation of MIMO nonisotropic fading environments with reverberation chambers

Some recent publications have extended the emulating capabilities of reverberation chambers. While polarization imbalance has been removed and Ricean-fading environments are now properly emulated, these chambers are still limited to isotropic nonline of sight (NLOS) scattering. By controlling the power received, number of resolvable multipath components (MPC), angular spread (AS), and angle of arrival (AoA), the emulation of real-propagating environments with both isotropic and nonisotropic scattering are demonstrated in this letter using a reverberation chamber with several multiple-input–multiple-output (MIMO) arrays.This work was supported in part by the Fundación Séneca, the R&D unit of the Autonomous Region of Murcia (Spain) under project references TIC-TEC 07/02-0005 and by the Spanish National R&D Programme through TEC2007/63470/TCM