Wideband circularly polarized rhombic loop antennas with different feed models

Two types of circularly polarized linear antenna having a rhombic loop configuration are investigated. One type of circularly polarized antenna is a single feed dual rhombic loop antenna (DRLA). The DRLA consists of two rhombic loops of the same size and is located above an infinite ground plane. The other is a hula hoop antenna (HHA). The HHA is fed from a coaxial cable, of which the inner conductor is connected to the antenna itself and the outer conductor is connected to the ground plane. Two types of feed are introduced for each of the DRLA and the HHA. The antenna characteristics for each feed model are calculated by the method of moments. The results are in good agreement with the measured data.