THREE-WAVE SHARED ANTENNA (RADIO, AM AND FM) FOR AUTOMOBILE

摘要

A three-wave shared antenna used in an automobile comprises an MT wave element (10A) characterized in that first and second phasing coils (11 and 12) are formed in an intermediate position of a conductive mast thereby forming the MT wave element (10A) is formed in a three-step collinear manner to be able to transmit/receive an MT wave, a trap element (10B) for interrupting the MT wave formed on top portion of the MT wave element (10A), and an auxiliary element (10C) for AM and FM waves, which comprises another conductive mast connected to said conductive mast through the trap element (10B) to be able to receive AM wave, which is a broadcast wave of an amplitude modulation system and FM wave, which is a broadcast wave of a frequency modulation system, in cooperation with said MT wave element (10A). Then, the electrical length of said auxiliary element (10C) for AM and FM waves is set to (3/4) wavelength of the electrical wave of the frequency close to the frequency of the transmission side in a radio telephone band, and the electrical length of said MT wave element (10A) is set to an electrical length in which the sum L of the length of said MT wave element (10A) and that of said auxiliary element (10C) for AM and FM waves adjusts to the reception of the FM wave.