VHF AND UHF COMMON USE ANTENNA

摘要

PURPOSE:To provide an excellent reception characteristic for three bands of a television broadcast program ad to provide a small sized VHF and UHF common use antenna. CONSTITUTION:A parallel resonance circuit 12 is interposed in series with an intermediate part of a main monopole element 10. A length L1 of the main monopole element 10 is 1/4 wavelength with respect to a frequency between a VHF lower band and a VHF high band. Furthermore, a resonance frequency of a parallel resonance circuit 12 is 140MHz between the VHF low band and the VHF high band. A sub monopole element 18 is arranged to the base end of the main monopole element 10 apart by a distance D of 15mm in parallel. The length L2 of the sub monopole element 18 is a 1/4 wavelength with respect to a frequency of a VHF high band. Then the base end of the main monopole element 10 is connected to a center conductor 20a of a coaxial cable 20 and the base end of the sub monopole element 18 is connected to an outer conductor 20b and a ground conductor 20 of the coaxial cable 20.