Endfire tapered slot antennas on dielectric substrates

Endfire tapered slot antennas are suitable for many integrated circuit applications, imaging and phased arrays. We report on an investigation of single elements of such antennas, including slots which are exponentially tapered (Vivaldi), linearly tapered (LTSA) and constant width (CWSA). For antennas of all types, a good general agreement is obtained for curves of beamwidth versus length, normalized to wavelength, when one compares the data with that for traveling-wave antennas published by Zucker. An important condition for this agreement is that the effective dielectric thickness, defined in the text, is in a certain optimum range. This condition is qualitatively explained in terms of the theory for traveling-wave antennas.