Communication apparatus, smart meter, and secondary battery

A communication apparatus mounted in a smart meter, comprising:

• a secondary battery;
• a transmitter-receiver circuit that is operable by using electric power supplied from the secondary battery;
• and
• an antenna that emits a wireless signal based on a transmission signal, which is output from the transmitter-receiver circuit, to a space,
• a circuit board on which the transmitter-receiver circuit, the battery and the antenna are mounted on a same side of the circuit board;
• and
• wherein the secondary battery is a lithium-ion battery having a thickness of 1 mm or less;
• wherein when electric power supplied from outside to the smart meter is cut off, the transmitter-receiver circuit outputs the transmission signal indicating a specified alarm to the antenna by using the electric power supplied from the secondary battery and thereby wirelessly transmits the alarm via the antenna;
• wherein the secondary battery has a first principal plane in contact with the circuit board and a second principal plane opposite the first principal plane:
• wherein the antenna is formed in a planar shape on the circuit board;
• wherein the secondary battery is placed so that the first principal plane and the second principal plane respectively become in parallel with the antenna;
• and
• wherein the secondary battery does not obstruct the wireless signal emitted from the antenna.