Niels Vesterdal Larsen

Analysis of Circularly Polarized Hemispheroidal Dielectric Resonator Antenna Phased Arrays Using the Method of Auxiliary Sources

The method of auxiliary sources is employed to model and analyze probe-fed hemispheroidal dielectric resonator antennas and arrays. Circularly polarized antenna elements of different designs are analyzed, and impedance bandwidths of up to 14.7% are achieved. Selected element designs are subsequently employed in a seven-element phased array. The array performance is analyzed with respect to scan loss and main beam directivity as a function of scan angle and frequency, and the influence of element separation is investigated.

An L-band, circularly polarized, dual-feed, cavity-backed annular slot antenna with wide-angle coverage

An L-band, circularly polarized, dual-feed, cavity-backed annular slot antenna has been investigated. The investigations comprise parametric studies of design parameters and measurements with different ground planes. The antenna has an impedance bandwidth of 6% around 1.59 GHz and a maximum directivity of about 7 dBi

An Analytical Method of Auxiliary Sources Solution For Plane Wave Scattering By Impedance Cylinders -- a Reference Solution For The Numerical Method of Auxiliary Sources

To facilitate the validation of the numerical Method of Auxiliary Sources an analytical Method of Auxiliary Sources solution is derived in this paper. The analytical solution is valid for transverse magnetic, and electric, plane wave scattering by circular impedance cylinders, and it is derived by transformation of the exact eigenfunction series solution. The transformation employs the Hankel function wave transformation to express the eigenfunction series of higher-order Hankel functions, with their singularities at the coordinate system origin, as a superposition of zero-order Hankel functions with their singularities at different positions away from the origin. The transformation necessitates a truncation of the wave transformation but the inaccuracy introduced hereby is shown to be negligible. The analytical Method of Auxiliary Sources solution is employed as a reference to investigate the accuracy of the numerical Method of Auxiliary Sources for a range of scattering configurations.

An analytical method of auxiliary sources solution for line source illumination of impedance cylinders

For a scattering problem with a circular impedance cylinder illuminated by a line source an analytical Method of Auxiliary Sources (MAS) solution has been derived. This may serve as B reference for the numerical MAS solution and comparisons between the analytical and numerical MAS solutions are presented. A very good agreement is found between the two MAS solutions with respect to excitation coefficients and mean boundary condition error for varying positions of the auxiliary sources and the Illuminating line source. This serves as a validation of the numerical MAS.

A Method of Auxiliary Sources approach for modelling the impact of ground planes on antenna radiation

A Method of Auxiliary Sources (MAS) approach is proposed to model the impact of finite ground planes on the radiation from antennas. Taking outset in a priori known antenna characteristics a scattering problem is formed in which the antenna is modelled by an incident field and the ground plane as a scatterer. Two different antenna test cases are shown and the calculated results agree well with reference measurements.