Communication apparatus and communication system

A communication apparatus comprising:

• a transmission line extending in a predetermined direction configured to communicate with a communication electrode of a communication partner apparatus through electromagnetic field coupling;
• a transmitter connected with a first end of the transmission line;
• and
• a terminator connected with a second end different from the first end of the transmission line,
• wherein the transmission line comprises:
• a first transmission line portion having a first characteristic impedance;
• a second transmission line portion disposed between the first transmission line portion and the transmitter and between the first transmission line portion and the terminator, and configured to provide a second characteristic impedance different from the first characteristic impedance;
• and
• a third transmission line portion disposed between the first and the second transmission line portions in the predetermined direction, and configured to provide a third characteristic impedance between the first and the second characteristic impedances,
• wherein the third characteristic impedance is larger than the second characteristic impedance and smaller than the first characteristic impedance.