Diagnosis of GNSS Antenna Arrays by method of Near-Field Measurements

Abstract

Inverse antenna problems have applications in the field of antenna diagnostics and antenna synthesis. This thesis work targets the antenna diagnostics application for the GNSS antenna arrays. Two different types of inverse algorithms, a modal based technique and an equivalent source technique have been successfully implemented and verified. Resolution is a key factor for antenna diagnostics applications to be able to differentiate the different elements constituting the antenna array. To improve the resolution of the equivalent source method, surface weighing technique has been employed. Surface weighing is accomplished by using sinusoidal expansion and 2D orthogonal square polynomials such as Chebyshev polynomials, Legendre polynomials and Zernike polynomials. A comparison study is done to verify how individual polynomials contribute to the betterment of resolution of the results.