A 1/spl times/2 dielectric-loaded helical antenna array

The helical antenna has been regarded as a broadband circular polarized radiating structure with relatively high gain since 1947. To facilitate its application in the mobile satellite communication, a cylindrical dielectric resonator (DR) can be utilized to enhance the forward tilt of the total electric field launched from the helix. This paper reports the design of a 1/spl times/2 linear cylindrical DR-loaded helical antenna array in the C-band. The helix is used to feed the wave to a long cylindrical rod of the DR which is loaded axially along the axis of the helical core. Size enlargement is an important feature in the design of an antenna for a satellite-based mobile communication in the C-band. Even when low-orbit satellites are used, the field strength on Earth will be very weak. Thus, a large aperture is needed to intercept the extremely feeble incident field. The radiation patterns of the unloaded helical antenna DR-loaded helical antenna and a 1/spl times/2 DR-loaded antenna array are compared. The effects of the inter-element spacing, the antenna gain, the VSWR and the axial ratio of the antenna array are also measured.