Radiation characteristics of linearly tapered slot antennas

The linearly tapered slot antenna (LTSA) is an endfire radiator formed by a tapered slotline that is usually supported on a thin, low- epsilon /sub r/ substrate. K.S. Yngvesson et al. (1985) have studied the radiation characteristics of LTSAs that are optimized for use in the focal plane of imaging/multiple-beam systems having f/D in the range of 1 to 2. In the present work, the author presents the results of an experimental investigation of the radiation properties of antennas with wider beamwidths. Some data on narrow-beamwidth antennas are included. Particular emphasis is placed on polarization in the intercardinal planes, where high levels of cross-polarization are observed. The study was conducted by fabricating four antennas on 30-mil Duroid ( epsilon /sub r/=2.2). In addition, two antennas were fabricated from 3-mil shim stock and supported by a styrofoam bridge to create antennas with air dielectric. It is concluded that the LTSA has many advantageous characteristics, and it is compatible with printed-circuit feed networks. However, designers should be aware of its polarization properties, which could adversely affect system performance.<>