Communication device and communication system

A communication device, comprising:

• a body configured to float on a liquid;
• a first antenna connected to the body and configured to be submerged in the liquid when the body is floating on the liquid,
• wherein the first antenna is wirelessly connected to a first communication network submerged in the liquid;
• and
• a first signal processing circuit connected to the first antenna and that processes a first signal,
• wherein the first signal is a radio frequency (RF) signal that is received from the first communication network that is submerged in the liquid by the first antenna or that is transmitted to the first communication network that is submerged in the liquid by the first antenna,
• wherein the first antenna comprises two circularly polarized antennas, and
• wherein the communication device further comprises:
• a first polarization switching circuit connected to a first of the two circularly polarized antennas;
• a second polarization switching circuit connected to a second of the two circularly polarized antennas;
• a switching control circuit connected to the first and second polarization switching circuits,
• wherein the switching control circuit switches the first signal that is transmitted or received between the first and second polarization switching circuits based on one of two received signals having a polarization having higher power at a time of reception.