**3.1. Drive coil L1**

For generating a spectral magnetic field a flat coil was used as a transmitting antenna built on a phenol board as printed circuit with the following characteristics:


The Network Analyzer employee served as a source of power in a frequency range of 100 KHz to 5 MHz applied. The combination coil and capacitance of the cables, that although were coaxial cables it presented a resonance frequency of 4.612 MHz This initial structure was proceeded with a series of measurements with actual physical capacitors with a dual role, first see the system answer at different values, and the second as reference calibration [13].
