2G/3G Serpentine Shape Inverted-F Antenna for Near Body Application

In this contribution, we present a miniature antenna placed in a leg bracelet for body worn applications. It operates in both the 820-960 MHz and the 1.7-2.1 GHz bands. The radiating element, based on an inverted-F antenna, occupies a 37 mm × 37 mm area and is printed on a flexible substrate that extends a multilayer circuit board. The serpentine shape helps to widen the bandwidths as well as minimize the size. The antenna is characterized for different situations: standalone, inside the plastic casing and worn close to the body inside the same casing. Both simulations and measured results are presented, and they agree well. The design steps are reviewed with the aid of current distribution simulation plots.