Designing a stacked three-element parasitic superdirective antenna

In this paper we investigate designing a stacked three-element antenna arrays for UHF band. The array is based on miniaturized printed half-loop antenna integrated in a PCB of 8 × 8cm2. To study the inter-element distance effect on the antenna performance (directivity, input impedance and radiation efficiency), a parametric analysis is performed. The obtained results show that for small distances high directivities can be achieved in the case of the fully driven element. However, to transform this array to a parasitic (loaded) one, negative resistances are required and neglecting these resistances significantly decrease the antenna directivity. The results are validated via measurements.