A simple and low-cost procedure for gel-like time-durable biological phantoms is presented in this work. Easily accessible materials are adopted, which are able to provide a flexible and controllable method to rapidly realize different kind of tissues. The proposed technique is applied to fabricate various tissue-mimicking phantoms, namely skin, muscle, blood and fat. Their effectiveness is first tested by performing dielectric characterization on a wide frequency range, from 500 MHz up to 5 GHz, and validating the measured dielectric parameters (dielectric constant and conductivity) by comparison with reference models in the literature. Then, a multi-layer phantom simulating the human arm is realized, and a wearable body sensor is adopted to prove the perfect agreement of the biometric response achieved in the presence of the fabricated phantom and that provided by a real human arm.

The specific advantage of fractal geometry to realize compact antenna features is exploited in this work for the design of a miniaturized Planar Inverted-F Antenna configuration with a large bandwidth. The conventional quadrilateral radiating element of a Planar Inverted-F Antenna is replaced by a Minkowski pre-fractal-based shape, thus increasing the resonant wavelength without affecting the overall antenna dimensions. Consequently, with the new design, a physically smaller antenna can achieve the same resonant frequency of a larger conventional configuration. Measured as well as simulated reflection coefficient and radiation patterns are presented to validate the assumptions. The impedance bandwidth of the antenna (2.19 to 2.52 GHz) covers the ISM band with a boresight gain of 1.5–2 dB over the entire band. Furthermore, to demonstrate the miniaturization effect, a successful comparison is provided with an identically sized, conventional square Planar Inverted-F Antenna design. The proposed antenna design can be usefully adopted for power-efficient communications in the framework of Wireless Body Area Sensor Networks.