The Japan Aerospace Exploration Agency (JAXA) plans to launch a geostationary satellite called Engineering Test Satellite VIII (ETS-VIII) in FY 2006. In this paper, a microstrip line array antenna, which has a very simple structure, is introduced to radiate a circularly polarized wave aiming at ETS-VIII applications. This antenna consists of a triangular conducting line with its vertexes rounded off, located above a ground plane, with a gap on one of its side to produce a circular polarization. The proposed antenna is analyzed by numerical simulations for a single element as well as for a three elements array configuration and the possibility of beam-switching in the azimuth space is experimentally confirmed in the latter case. It is found that by properly feeding the elements constituting the array antenna, for an elevation angle El = 48in Tokyo area, three beams are created in the conical-cut direction with a minimum gain more than 6.6 dBic and an axial ratio less than 3 dB.

A compact antenna is proposed for operating at the Federal Communications Commission allocated ultra-wideband (UWB) of 3.1-10.6 GHz. The antenna is made by deforming a film antenna which consists of two glass-shaped and square-shaped radiation elements. The antenna in its planar form is optimized for the UWB operation and is deformed by different manners such as folding, meandering or twisting, without much influence on its input characteristics. The deformations not only miniaturize the antenna but also improve its radiation characteristics. A prototype with a dimension of 2033 mm2 is fabricated and then the antenna is deformed by rolling it into a circular rod with a diameter of 6.4 mm, or meandering it into a square rod with a cross-sectional dimension of 65 mm2. The deformed antennas maintain the operation at the UWB and have better omni-directional radiation patterns than the antenna in its planar form.