Fundamental properties and applications of semi-active arrays

Semi-active antennas include a set of hybrid matrices between the distributed amplifier modules and the radiating elements. The inclusion of these hybrids allows for control of the aperture distribution while maintaining all amplifiers at equal power level for optimum DC to RF efficiency. This paper focuses on planar arrays applications, for which the concept is of interest for zooming, beam contouring and sidelobe control. A few fundamental properties of this class of arrays such as scan performance and achievable sidelobe levels are presented for linear and planar arrays. Two specific examples are studied in detail.