Browsing by Author "Rajo-Iglesias, Eva"

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Dual-Band Implantable Antenna Based on Short-Circuited SRR
(2010)
Sanchez-Fernandez, Carlos J.
;
Quevedo-Teruel, Oscar
;
Requena-Carrion, J.
;
Inclan-Sanchez, L.
;
Rajo-Iglesias, Eva
In this communication, an innovative dual band microstrip patch antenna is proposed for Implantable Medical Devices (IMD). Particularly, the covered bands are MICS (402-405MHz) and ISM (2.4-2.48GHz). The antenna has a multilayer configuration where the feeding line and radiating layer are located at different levels. The radiating element of the antenna is a Split Ring Resonator (SRR) coupled to a Spiral. Both elements are short-circuited to the ground plane to achieve size reduction. In addition, the effects of human body geometry and dielectric properties are studied. Three models are investigated: single-layer, three-layer and a realistic human body based on the Voxel Man dataset.
Dual-Band Patch Antennas Based on Short-Circuited Split Ring Resonators
(2011-08-01)
Quevedo-Teruel, Oscar
;
Kehn, Malcolm Ng Mou
;
Rajo-Iglesias, Eva
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A study of an innovative antenna based on split ring resonators (SSRs) is presented. SSRs have been exhaustively used in the literature as the unit cell of periodic structures for obtaining left-handed media, whose interesting characteristics can be applied to waveguides or antennas. In this work, the authors propose the use of only one unit cell of a double SRR as a radiator. The double SRR is printed on a grounded dielectric slab, acting as the radiating element of a microstrip patch antenna, and grounded pins are used to short-circuit the structure for size reduction. A compact dual band antenna is obtained in this way. For example, a particular design making use of PP (epsilon(r) = 2.2) as substrate allows a size of 0.05 lambda(o) x 0.05 lambda(o) for the lower frequency of operation with an acceptable radiation efficiency. Simulated and measured results of return losses, gain and radiation efficiency of this new type of patch antenna are provided.
Enhancing the Efficiency of Compact Patch Antennas Composed of Split-Ring Resonators by Using Lumped Capacitors
(2012)
Pucci, Elena
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Rajo-Iglesias, Eva
;
Kehn, Malcolm Ng Mou
;
Quevedo-Teruel, Oscar
;
電子工程學系及電子研究所
A new type of small patch antenna with low profile and enhanced radiation efficiency is proposed in this letter. The antenna is realized with a double layer of low-permittivity material (polypropylene, epsilon(r) = 2.2). The lower layer is used for the feeding of the antenna, and split ring resonators (SRRs) are printed on top of the upper layer acting as radiating elements. The compactness is provided by shorting the rings to the ground plane with two metal pins. Although this antenna presented initially a dual band of operation, it has been demonstrated how the use of a lumped capacitor in the inner ring can increase the total radiation efficiency of the antenna performing a single-band response. Therefore, when the two original operation frequency bands coincide, a manufactured prototype of the antenna demonstrated a measured radiation efficiency of 73% that can be provided at the operation frequency of 1.29 GHz.
Reconfigurable Loaded Planar Inverted-F Antenna Using Varactor Diodes
(2011)
Kehn, Malcolm Ng Mou
;
Quevedo-Teruel, Oscar
;
Rajo-Iglesias, Eva
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This letter presents a compact reconfigurable multiband microstrip antenna. The multiplicity of bands is achieved by the use of concentric external metallic semirings around a central internal semicircular microstrip patch. These are all shorted to the ground plane via a vertical metallic wall through the common diametric plane, thereby adopting the concept of the planar inverted-F antenna (PIFA) for size reduction and thus compactness. The operation frequencies are tuned by varactor diodes placed between the inner semicircular patch and the outer half-rings. In addition to tunability, the overall bandwidth may also be widened by combining the tunable range. Theoretical simulations and measurements of manufactured prototypes agree well with each other.
Reconfigurable Multilayer Patch Antennas Based on Metamaterials
(2010)
Sanchez-Fernandez, Carlos J.
;
Quevedo-Teruel, Oscar
;
Malcolm Ng Mou Kehn
;
Rajo-Iglesias, Eva
;
電機工程學系
Along this document, the reconfigurability possibilities of a dual band microstrip patch antenna based on short-circuited SRR is studied. Since the antenna presents a narrow bandwidth, reconfigurability techniques has been implemented to extend the effective bandwidth of the device. The proposed antenna has a multilayer configuration where the feeding line and the radiating layer are located at different levels. A previous study by using lumped elements has been carried out and taking into account these results, the final reconfigurable version has been implemented by using varactor diodes.