Showing papers on "Front-to-back ratio published in 1987"

High front-to-back ratio type yagi antenna

Abstract: PURPOSE:To realize a high front-to-back ratio and to eliminate the disturbance of same frequency interference used for a general antenna by constituting a reflector by means of alternate provision of a half wavelength element and a one-wavelength element consisting of two half wavelength elements arranged in a line. CONSTITUTION:A reflector 33 consists of reflection elements 33a, 33b and 33b' each having a half wavelength in the titled antenna comprising a radiator 32, the reflector 33 and a director 31 consisting of six direction elements whose length is a half wavelength with respect to the operating frequency. That is, the element 33a is fitted at the side of the radiator 32 as a half wavelength resonance element, and the other elements 33b, 33b' are arranged in a line at the reflection side to forms a one-wavelength resonance element. Further, each element is arranged in parallel on one and same plane and supported by an arm 34. Thus, a high front-to-back ratio is obtained by using the reflector 33 comprising the elements 33a, 33b and 33b' having a resonance length different from the front and back directions in the same band in this way. Moreover, the titled antenna is used for various applications to eliminate the disturbance of same frequency interference or to expand the service area.