Compact Antennas and Arrays for Unmanned Air Systems Compact Antennas and Arrays for Unmanned Air Systems Compact Antennas and Arrays for Unmanned Air Systems
A simple and novel dual-CP printed antenna is modelled and measured. The patch antenna is small and achieves a low axial ratio without quadrature feeding. The measured pattern shows axial ratio pattern squinting over frequency. Possible methods of improving the individual element are discussed, as well as an array technique for improving the axial ratio bandwidth. Three endfire printed antenna structures are designed, analyzed, and compared. The comparison includes an analysis of costs of
... s of costs of production for the antenna structures in addition to their performance parameters. This analysis concludes that cost of materials primarily reduces the size of antennas for a given gain and bandwidth. An antenna stucture with an annular beam pattern for down-looking navigational radar is proposed. The antenna uses sub-wavelength grating techniques from optics to achieve a highly directive planar reflector which is used as a ground plane for a monopole. A fan-beam array element is fabricated for use in a digitally steered receive array for obstacle avoidance radar. The steered beam pattern is observed. The element-dependent phase shifts for a homodyned signal in particular are explored as to their impact on beam steering.