J. Gemio

HUMAN BODY EFFECTS ON IMPLANTABLE ANTENNAS FOR ISM BANDS APPLICATIONS: MODELS COMPARISON AND PROPAGATION LOSSES STUDY

In this paper propagation losses of body implanted antennas are studied at the ISM bands of 433MHz, 915MHz, 2450MHz and 5800MHz. Two body models are used, one based on a single equivalent layer and the other based on a three layer structure, showing the advantages and limitations of each one. Firstly, the antenna pair gain at difierent implanted antenna depths is analyzed. Next, we show the efiects of the thickness of the difierent body tissue layers. Finally, we discuss the consequences of using a coating layer to isolate the antenna from the harsh environment of the human body.

Dual-Band Antenna With Fractal-Based Ground Plane for WLAN Applications

In this letter, a triangular monopole on a fractal-based ground plane is designed to obtain a dual-band antenna for the 802.11 standard (WLAN). The ground plane is based on a mod-2 Sierpinski gasket repeated four times and rotated to obtain a square ground plane. The operating bands of the antenna are adjusted using the height of the monopole, the dimensions of the ground plane and the scale factor used to create the fractal shape. Simulations and measurements are in good agreement showing the advantages of using the fractal-based ground plane instead of the solid ground plane.

Concentric Annular-Ring Microstrip Antenna With Circular Polarization

In this letter, we present a concentric annular-ring microstrip antenna that covers the bands of Galileo (E5a, E5b, E1, E2, L1), GPS (L1, L2, L5), and GLONASS (L1, L3). This microstrip antenna is fed by four apertures that improve the coupling. Broad band phase shifters and Wilkinson power combiners are used to generate the required circular polarization.

A Split-Ring-Resonator Loaded Monopole for Triple Band Applications

A monopole loaded with a split-ring resonator (SRR) will be presented for applications requiring efficient triple-band performance. The design is based on the principle of non-resonant traps and takes advantage of the dual-band behavior of the SRR. The mid-band frequency is mainly controlled by the dimensions of the monopole whereas the frequencies of the lower and upper bands are determined by the resonances of the SRR. As proof of concept, an antenna covering the universal 802.11 standard (2.4–2.5 GHz and 4.9–5.875 GHz) and the low band of the 802.15 standard (3.244–4.742 GHz) has been designed, fabricated and measured.

Resonator-Loaded Dual-Band Monopole for Universal WLAN

This letter presents a novel monopole antenna design for efficient dual-band operation over the entire international wireless local area network (WLAN) frequency bands of 2.4-2.5 GHz (802.11b/g) and 4.9-5.875 GHz (802.11a/h/j). The design is based on the principle of out-of-band loading using a magnetic resonator whose natural frequency is chosen to lie between the lower and upper WLAN bands. The position of the resonator and the frequency of its natural resonance are chosen to produce more than 1 GHz wideband match in the 5 GHz band. The length of the monopole combined with the out-of-band resonator inductance determines the match in the 2.45 GHz band.

IMPROVING SILICON INTEGRATED ANTENNAS BY SUBSTRATE MICROMACHINING: A STUDY OF ETCHING PATTERNS

One of the main drawbacks of antenna integration on standard CMOS silicon substrates are the low radiation e-ciency levels obtained due to the high silicon losses. This paper studies the use of micromachining techniques to remove silicon beneath the antenna as a solution to improve radiation e-ciency. Several etching patterns are analyzed for difierent etching depths through simulations and measurements in order to flnd out which are the best ones for the micromachining process. Results are verifled in two operating scenarios.

New multiband asymmetric top-loaded mod-p antenna for terrestrial and satellite communication services

A novel multiband monopole antenna that provides omnidirectional and broadside radiation patterns using only one single-fed element is presented. The radiating element consists of an asymmetric dual-brand top-loaded fractal-inspired mod-2 monopole where the frequency bands are adjusted by the mod-p structure, and the pattern by the top-loading structure.

Performance Evaluation and Design of Stacked Crystal Filters

When very small size, microwave frequency and high quality factor resonators are required, bulk acoustic wave (BAW) resonators are generally used. However, in devices such as oscillators, the use of two stacked BAW resonators, a structure known as stacked crystal filter, can help to overcome the fundamental trade-off between tunability and phase-noise performance. For that reason, this paper evaluates the performance of this type of resonators, and it presents a collection of closed-form expressions for its primary design.