Interest in terahertz science has expanded rapidly in recent years due largely to the advent of new RF components and new fast-pulse optical time domain spectroscopic techniques. The two traditional development communities that border the terahertz gap - optical and microwave, are beginning to converge as we see more wide spread use of terahertz systems. One technology area where both these communities can benefit is in the design and realization of new forms of terahertz antennas and beam forming networks. Both frequency domain and optical time domain techniques make use of single mode, broad band terahertz antennas. However, most existing instruments utilize very simple structures that have been imported from the microwave community. The very special needs of newly proposed terahertz instruments, especially very wide band-width spectroscopy and high resolution imagers, require new antenna concepts and new ways of implementing already established antenna designs. More traditional applications for terahertz systems, in radio astronomy, remote sensing and radar, generally require large diameter, high surface accuracy antenna dishes that can benefit from active surface correction, new light weight materials and compact designs. This paper provides a brief overview of terahertz antenna issues from large scale reflectors to multipixel imaging systems. It is intended as an introduction to a field with both wide breadth and applications that cross many disciplines.