Note that all simulations are made by using the
commercially available simulation software, Ansoft High
Frequency Simulator Structure (HFSS) 14. Here, a Monza 4
chip with an input impedance of 11 143 − Ω j and a threshold
power sensitivity of -17.4 dBm at 915 MHz is provided. The
input impedance of the fabricated prototype antennas (as
shown in Fig. 6) has been measured with Agilent E8358A.