In this paper, the design and radiation performance of a miniature antenna embedded in small devices with a wrist-watch form factor, operating in both MICS (Medical Implant Communication Service) (402.0-405.0 MHz) and Bluetooth (2.4-2.483 GHz) bands, are presented. The radiating element, based on a spiral shape Planar Inverted-F Antenna (PIFA), was fabricated and tested. Simulated and experimental results of the structure are compared and discussed. As this antenna is dedicated to be embedded in a watch, the influence of its interaction with the other parts of the device such as batteries, transceiver, and the LCD is investigated. The influence of the wrist of the user on the antenna performance is also considered.

Two different types of inverted-F antennas which can be integrated into a micro-SD (μSD) card are presented. The antennas operate in the new band from 2.4835 to 2.5 GHz dedicated to medical applications. The volume available for the antenna in the μSD card is only 11 × 3 × 1 mm3. Performance in terms of bandwidth, the radiation efficiency and the gain of the two structures is compared and discussed. The μSD card is intended to fit multiple devices with different ground plane dimensions. As an example, the influence of the μSD card position on a standard printed circuit board of 100 × 40 mm² is also studied.

In this paper, we present the study the design and radiation performance of and the optimization of miniature antennas embedded in small devices of various form factors including wrist-watch or pendant, operating in both MICS (402.0-405.0 MHz) and WIFI (2.4-2.483 GHz) bands. Two structures based on Planar Inverted-F Antennas (PIFAs) are proposed, and prototypes are fabricated and tested. Performance in terms of bandwidth, radiation efficiency and gain of the two structures are compared and discussed. As these antennas are dedicated to be placed in contact with the user, the influence of the human body on the antenna performance is investigated.

A multiple input multiple output (MIMO) antenna operating in the WIFI band (2.4-2.483 GHz) is proposed in this paper. It is made up of two curved Planar Inverted-F Antennas (PIFAs) laid on a metallic disk of 50mm diameter. To decrease the mutual coupling between the radiating elements, the orientation of the second antenna is tilted from 100° relative to the first one and a metallic wall connected to the ground plane is added. A final isolation better than -15 dB, is obtained with this structure. The simulated S-parameters are compared with measurement and a good agreement is found. The measured peak gain, the computed envelope correlation coefficient and the diversity system gain are respectively 2 dBi, 0.035 and 9.78 dB. As the antenna is dedicated to work close to the human body, the effect of the latter on the antenna performance is investigated.