Signals in a waveguide travel at a speed that varies with frequency and the dimensions of the waveguide.
In a phased array or slotted waveguide antenna, the signal is designed to reach the outputs in a given phase relationship. This can be accomplished for any single frequency by properly adjusting the length of each waveguide so the signals arrive in-phase. However, if a different frequency is sent into the feeds, they will arrive at the ends at different times, the phase relationship will not be maintained, and squint will result.
Frequency-dependant phase shifting of the elements of the array can be used to compensate for the squint, which leads to the concept of a squintless antenna or feed.
In some cases the antenna may be designed to create a squint. For example, an antenna which is used to communicate with a satellite but must remain in a vertical configuration. Squint is also required in conical scanning.
^Ishii, T (1995). Handbook of microwave technology. San Diego: Academic Press. p. 180. ISBN 978-0-08-096237-5.
^Seyed Kasra Garakoui, Eric A.M. Klumperink, Bram Nauta, Frank E. van Vliet, "Phased-Array Antenna Beam Squinting Related to Frequency Dependency of Delay Circuits"
^Rudge, Alan W. (1982). The Handbook of Antenna Design. IET. p. 132. ISBN 9780906048870. Retrieved 8 September 2017.
^Lee, S. W. (1993). Antenna Handbook: Volume III Applications. Springer Science & Business Media. pp. 18–19. ISBN 9780442015947. Retrieved 8 September 2017.
^Latham, C. (1985). "MARTELLO – A MODERN THREE-DIMENSIONAL SURVEILLANCE RADAR". The GEC Journal of Research. 3 (2): 104–113.