PLANE ANTENNA

PURPOSE:To facilitate an optimum design corresponding to the electric field strength of a satellite broadcasting wave by adding an additional branch to have the phase difference of the integer-fold wavelength lambdag of a transmitting and receiving wave to the arbitrary branching branch of a feeding circuit pattern, and simultaneously, providing a additional radiating circuit element corresponding to the additional branch to a radiating circuit pattern. CONSTITUTION:An additional branch 7 is formed to have the phase difference of the wavelength lambdag of the transmitting and receiving wave, one radiating circuit element 8 is added, and the additional branch 7 is formed by using a lambdag/4 transformer 9. Further, in order to avoid the unbalance of a power generated since the additional radiating circuit element 8 is added, a non-equipartition branching circuit 10 to be formed with a 2:1 power divider is properly provided on the branching part of a feeding circuit pattern 2. Consequently, the design in which the number of the radiating circuit elements is except 2 can be executed. Thus, a flat antenna to have an optimum gain corresponding to the electric field strength of the satellite broadcasting wave and, moreover, to be a minimum size can be easily designed.