Abstract: A radio transmitter includes a radio module, a battery from which power is fed to the radio module, and a metal plate. The radio module includes a transmission module generating a transmission signal and an antenna configured to wirelessly transmit the transmission signal. The metal plate is located so as to cover a part of the battery and a part of the antenna. The battery is electromagnetically coupled to the antenna. A main radiation direction of the antenna is parallel to a principal surface of the metal plate.

Abstract: A radio transmitter includes a radio module alternately repeating a communication mode in which power is consumed to wirelessly transmit predetermined information and a standby mode in which standby power is consumed with no radio transmission performed, and a power supply section supplying power to the radio module. The power supply section includes a secondary battery storing power, a solar battery converting light energy into power, and a charging circuit controlling power supply from the solar battery to the secondary battery and power supply from the secondary battery to the radio module. The charging circuit feeds power from the solar battery to the secondary battery during a period of the standby mode.

Abstract: A radio transmitter includes a radio module, a battery from which power is fed to the radio module, and a metal plate. The radio module includes a transmission module generating a transmission signal and an antenna configured to wirelessly transmit the transmission signal. The metal plate is located so as to cover a part of the battery and a part of the antenna. The battery is electromagnetically coupled to the antenna. A main radiation direction of the antenna is parallel to a principal surface of the metal plate.

Abstract: An optical information recording/reproducing apparatus having a laser light source driven through a high frequency imposing circuit comprises a high frequency imposing circuit, electrical terminals of said laser light source being enclosed by a conductive shield case, which is composed of a pair of half cases, each of half cases contacting with the other half case and having a wall which overlaps with a wall of the other half case, a capacitor being coupled between at least of of lead lines for external connection of said high frequency imposing circuit and said laser light source, and ground, a junction of said capacitor and said lead line locating close to a wall of said shield case, and said lead line for external connection being taken out of the shield case through a gap between overlapping walls of said two half cases.