Broadband reconfigurable active power splitters/combiners for multifunction systems

This report describes the work performed within a project named REKON. The purpose is to study one type of analog reconfigurable circuits. The circuits considered in REKON are reconfigurable broadband active power splitters and power combiners in MMIC (Monolithic Microwave Integrated Circuits) technology intended for multifunction antennas. A number of future military platforms will be composed of a combined system for radar, communication and electronic warfare (EW). This can be called a multifunction array antenna system (MFA-system) with a common set of beamforming circuitry, transmit/receive modules and antenna aperture. A solution for a common reconfigurable beamforming network can be achieved by a combination of a number of the proposed reconfigurable powersplitters/combiners. Reconfigurability is not only needed in the feed network of a beamformer but also in the power amplifier stage close to the antenna aperture. A reconfigurable power amplifier then allows for the possibility of reducing the radar cross section (RCS) for parts of the antenna aperture that is switched off. This is achieved by reconfiguring the amplifier stage into an adaptive termination for the antenna element. The concept, which has proven to be successful in practice leads to the conclusion that we have taken one step further towards the vision of multifunction antennas which, if they are realised, will give both increased functionality and reduced total cost as well as decreased radar cross section for the systems. The research results will be of use to Swedish defence industry through joint projects like MFA (MultiFunction Antennas and ESGAS.