# Characterization of a Mechanical Antenna Based on Rotating Permanent Magnets
## 2 Related Works
\begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Design** & **Magnetic Field** & **Frequency** & **Theory** & **Applications** & **Reference** \\ \hline One rotating permanent magnet made from & 1.67 \(\upmu\)T @ 0.5 m & 30 Hz & \multirow{2}{*}{American current model} & Underwater, underground communications & [1] \\ NdFeB, rectangular & 0.25 nT @ 1 m & & & \\ \hline Rotating shutter, four fixed rectangular & 12 nT @ 1 m & & & \\ NdFeB permanent magnets & 18 pT @ 5 m & & & \\ \hline Rotating shutter, eight fixed rectangular & 3.1 nT @ 1 m & & & \\ NdFeB permanent magnets & 44 pT @ 5 m & & & \\ \hline One rotating NdFeB permanent & 1.5 LT @ 2 m & & & \\ magnet, cylindrical & 17 nT @ 8.4 m & & & \\ \hline Two rotating NdFeB permanent magnets, ring-shaped, radially magnetized & 0.95 nT @ 1 m & & & \\  & 2.35 nT @ 10 m & & & \\ \hline Magnetic Pendulum Array (MPA) made of 28 NdFe cylindrical permanent magnets, diametrically magnetized & 0.5 nT @ 10 m & & \\ \hline One rotating NdFeB permanent magnet, cuboidal, with a volume of & 0.03 nT @ 30 m & & \\ \hline One rotating NdFeB permanent magnet, & 2 pT @ 1 m & & \\ cuboidal, with a volume of & 2 pT @ 1 m & & \\ \hline 6 mm\({}^{3}\) (simulation) & 1.4 pT @ 3.5 m & & & \\ \hline One triangular array of NdFeB & 11.8 V @ 0.15 m & & & \\ permanent magnets & 0.85 V @ 0.5 m & 15 Hz & Rotating magnetic dipole & Underground and underwater communications & [8] \\ \hline One rotating NdFeB permanent & 0.114 mV @ 1 m & 5 Hz & & \\ magnet, rectangular & 0.112 mV @ 1 m & & \\ \hline One vibrating NdFeB permanent & 0.179 mV @ 1 m & 5.8 Hz & & \\ magnet, rectangular & 0.179 mV @ 1 m & 6.4 Hz & & \\ \hline Resonant magneto-mechanical transmitter & 1 f (// \(\upmu\)T @ 1 & & \\ NdFeB magnets with square cross section & extrapolation) & 166 Hz & Point dipole with moment Mr & Low data rate communications & [10, 11] \\ \hline Resonant magneto-mechanical transmitter (MMT) with one rotor and two stators of NdFeB & 0.34 T @ 1 km & & & \\ NdFeB magnets with a square cross section & (1// \(\upmu\)T @ 1 & & \\ \hline Mechanical antenna array with rotating & 31.6 nT @ 10 m & & & \\ NdFeB cylindrical magnets, axially magnetized & 0.05 nT @ 80 m & 75 Hz & & \\ \hline Magnetoelectric (ME) mechanical antenna & & & & \\ based on a PZT/ Meteglas fixed structure: one & -0.01 nT @ 5 m & 11.32 kHz & Current loop (for comparison with the ME antenna) & Wireless signal transmission & [13] \\ \hline Magnetostrictive Terlemed-D and & & & & \\ piezoelectric PZT laminate with 4 Rb & 2.8 μ T @ 5 cm & & & \\ magnets for DC polarization & 13 nT @ 30 cm & & & \\ \hline One rotating NdFeB permanent magnet, & & & & \\ cylindrical, diametrically polarized, & 0.6 \(\upmu\)T @ 1 m & 22 Hz & Basic coil & Communication systems & [15] \\ suspended between two high-permeability & & & & \\ laminated pole pieces & & & & \\ \hline One rotating NdFeB permanent magnet, & & & & \\ ring-shaped, diametrically magnetized & 800 pT @ 10 m & & & \\ \hline Transmitter with electrically modulated & 17.8 nT @ 0.3 m & & & \\ replacement (EMR) having one rotating & & & & \\ spherical NdFeB permanent magnet and a & 1 \(\upmu\)T @ 0.74 m & & & \\ \hline Transmitter with electrically modulated & & & & \\ reluctance (EMR) having one NdFeB & 0.17 nT @ 1.2 m & 430 Hz & Electric field generated by a & Various VLF and & [18] \\ rectangular permanent magnet, seven layers of Meteglas sheets, and a coil & & & & \\ \hline \hline \end{tabular} Data obtained from the bibliographic study are used for the comparative analysis of the results relative to other structures for producing LF/ULF magnetic fields like coils/solenoids as well.  
\end{table} 
Table 1: Performances of various mechanical antennas with permanent magnets.