Enhancing circular polarization characteristics of a dipole-fed cross spiral antenna

The way to improve circular polarization characteristics of a dipole-fed cross spiral antenna is presented. The dipole-fed cross spiral antenna that can radiate circularly and linearly polarized wave at three or more bands is invented by the author. Improving band-width and radiation-gain and - efficiency of circular polarization has been a problem which should be solved for applying it to mobile communication devices. A simple way to enhance these circular polarization characteristics is presented in this paper. By using the suggested arrangement, the dipole-fed cross spiral antenna has radiated circular polarization with 2 dB or more radiation-gain and 80 % or more radiation-efficiency within 22MHz or more band-width.