Radiation from Grating Antennas on Dielectric Waveguides of Finite Width

A practical and systematic approach is presented for calculating the radiation properties of dielectric grating antennas of finite width. Such grating antennas, which show great promise for the millimeter-wave range, are placed on dielectric waveguides, such as the rectangular dielectric image line, which are necessarily of finite width. The complications introduced by the finite width are overcome in this approach by employing a new rigorous intermediate solution and an approximation relating to the sides of the antenna. Since the finite width of the antenna influences the scan angle and beam width of the radiation, this approach yields the effects of electronic beam scanning. Furthermore, the finite width introduces TE-TM coupling, which produces significant cross-polarization effects.