In-antenna power-combining methods

In this paper different possibilities for an in-antenna power-combining approach are investigated. The radiation is based on the principle of an integrated lens antenna (ILA), where the primary radiator consists of a slot antenna with two or more excitation elements. The output power of parallel amplifiers can be directly combined in the primary radiator itself without any additional combiner network. Regarding the antenna efficiency, the practical limit for the number of parallel branches is found out by simulations. Additionally, different power-splitter networks for achieving a linearly or circularly polarized radiation are presented and it is shown how the input impedance of the excitation elements changes with different number of feed-lines. Finally, primary radiators with different input impedances and polarization schemes are presented and verified by calibrated gain measurements in D-band and H-band frequencies.