The spherical inverted-F antenna (SIFA) is a relatively new conformal antenna design that consists of a microstrip patch resonator on a spherical ground. The SIFA resembles a planar inverted-F antenna (PIFA) that has been conformally recessed onto a sphere. The basic design, simulation, and fabrication of a SIFA were recently reported. The aim of this thesis is to provide a three-fold improvement to the study of the SIFA: the fabrication of a dielectric-coated SIFA, a new analytical model based on the cavity method, and the analysis of a randomly oriented SIFA’s operation in a remote networking scenario. A key improvement to the basic SIFA design is the addition of a lossy dielectric coating to the outside of the sphere for purposes of impedance stability, bandwidth control, and physical ruggedization. The first contribution of this thesis is the fabrication of such a dielectric-coated SIFA. Two antennas are fabricated: a coated SIFA operating at 400 MHz, and an uncoated SIFA operating at 1 GHz for comparison. Both SIFAs are constructed of foam and copper tape; the coating is comprised of silicone rubber and carbon fiber. The fabricated designs perform with reasonable agreement to corresponding simulations, providing a basic proof of concept for the coated SIFA. The SIFA was previously studied analytically using a transmission line model. The second task of this thesis is to present a new model using the cavity method, as employed in microstrip patches. The SIFA cavity model uses a curvilinear coordinate system appropriate to the antenna’s unique geometry and is able to predict the antenna’s performance more accurately than the transmission line model. The final portion of this thesis examines the performance of the SIFA in a remote network scenario. Specifically, a line-of-sight link between two SIFAs operating in the presence of a lossy dielectric ground is simulated assuming that each SIFA is randomly oriented above the ground. This analysis is performed for both uncoated and coated SIFAs. A statistical analysis of the impedance match, efficiency, and power transfer between these antennas for all possible orientations is presented that demonstrates a design tradeoff between efficiency and predictability.

Att koppla samman nätverk över geografiskt olika platser har blivit allt vanligare i dagens samhälle. Rapporten kommer belysa olika WAN-lösningar för att göra detta möjligt. De olika lösningar som kommer belysas i denna rapport är att hyra egen fiber, lager2-länk, MPLS och även VPN. Det kommer göras jämförelser mellan dessa lösningar när det gäller kostnad, säkerhet, hastighet och tillförlitlighet. Detta har gjorts med vetenskapliga artiklar och intervjuer men rapporten innefattar även en praktisk tillämpling i form av ett experiment. / To connect networks across geographically diverse sites has become increasingly common in todays society. This report will highlight the various WAN solutions to make this possible. The different solutions that will be highlighted in this report is rent own fiber , Layer 2 link, MPLS , and VPN. There will be comparisons between these solutions in terms of cost, safety , speed and reliability. This has been done with scientific articles and interviews , but the report also includes a practical laboration.