CORDLESS TELEPHONE HANDSET

摘要

PURPOSE: To set detuning to a minimum by making a handset antenna means flat in specified dimensions (which do not exceed 1/4 of the waveform of a transmitter-receiver means) and arranging it so that it extends in a vertical direction. CONSTITUTION: An antenna 48 is balanced against the chassis grounds of a high frequency circuit board 41 and a processor circuit 38 and the two grounds are connected. The metallic structure of an earphone transducer R is returned to high frequency ground and it forms a shield means against detuning caused by the approaching ear of a user. The dimension of the antenna 48 containing an upper end extension part is 7cm, and the dimension of (wavelength of about 1/100 at 6m wave) lateral direction is 3cm. The side extension part is formed by the copper foil of 2cm×3cm. The antenna board 48 is provided to become a vertical face at the time of use and a radiation system is a vertical board form counterpoised for a flat and vertical conductor. The side extension part 56-56 and an upper extension part 58 increase antenna capacitance and reduce detuning.