Comments on "A shaped reflector antenna for 60-GHz indoor wireless LAN access points"

The author comments that the shaped reflector antenna principles and theory of Smulders, Khusial and Herben (see ibid., vol.50, p.584-91, Mar.2001) are based on the papers described by Kumar (see Proc. Montech '86 IEEE Conference on Antennas and Communication, 1986, IEEE Cat. No. TH0156-0, Inst. Elect. Eng. Proc., vol.134, p.106-108, 1987 and Technology Symposium, 1990). These papers described the X-band, circularly polarized shaped beam telemetry antenna suitable for retransmitting the radar data back to an earth terminal. Smulders et al. have used the same principle, and similar types of radiation patterns are produced. However, two points are different in their paper: (1) the design frequency (60 GHz) and (2) the application of antenna for indoor wireless LAN access points. Therefore, they authors should have referenced Kumar's papers. Smulders et al. agree with Kumar's comments that reflector shaping is nothing new. However, we took into account diffraction effects (by applying the uniform theory of diffraction) whereas the shaping in the paper of Kumar is based on geometrical optics, only. We showed that according to our approach, a more smooth illumination function can be achieved and how the smoothing effect depends on the amount of edge illumination. We also showed in which way the spatial field deviation can be minimized and that this could save a few decibels in the link budget.