Design of a NIC active oscillating patch antenna using NDF as linear design tool

This paper shows the design process of an active patch antenna with a Negative Impedance Converter (NIC). The NIC is used as a negative admittance to increase the Q of the oscillating antenna. The design is performed using the proposed Normalized Determinant Function (NDF) method and a classic linear methods. The proposed NDF method demonstrates advantages compared with classic methods, as the prediction of the Q for any topology and the lack of proviso requirement. The Harmonic Balance (HB) analysis and measurements of the prototypes confirm, in favour of NDF, the stability discrepancies between classic methods and NDF. Finally, the linear estimation of the improvements introduced by a NIC are questioned by the risk of instabilities and the introduction of new noise sources.