Upper Bound on Transducer and Radiation Efficiencies of a Multiport Antenna Arrays

The optimal performance of MIMO antennas is studied via the tools of convex optimization, utilizing two different concepts of power entering radiating systems: available and incident power. Two figures of merit – radiation and transducer figures – are defined as Rayleigh quotients over network system matrices and used to study several cases involving dipole antennas of various arrangements and balun transformers. It is concluded that the design strategy significantly differs depending on the amount of information known about the MIMO system and its excitation.