BeamscanEstimator example fails when carrier frequency is changed

I am attempting to develop an angle of arrival estimator and have started by investigating the phased.BeamscanEstimator as presented as part of the Matlab example http://www.mathworks.com/examples/phased-array/1972-direction-of-arrival-estimation-with-beamscan-and-mvdr?s_tid=srchtitle The example code executes perfectly "as is". However, when I change the carrier frequency fc from 300E6 to 400E6, the estimation result fails. Examination of the spatial spectrum shows an additional peak generated as the carrier frequency increases. Can someone advise me regarding what parameter limit I have violated and why?

More generally, where might I find the parameter range limits for this and other direction of arrival estimation objects?

Answer 1

[Honglei Chen]

Hi Roger,

Did you update the array? The example uses an array with an element spacing of 0.5 meters, which is half wavelength for 300 MHz. If you change the wavelength to 400 MHz, this spacing introduces aliasing. You may want to set the spacing to half wavelength corresponding to 400 MHz to avoid the aliasing.

HTH