The coupling and radiation characteristics between two groove-backed or cavity-backed slot antennas are investigated. Usually, groove and cavity are used to enhance the radiation efficiency and antenna impedance matching by reducing the image current effect. Also it is useful to reduce the direct wave coupling which corrupts receiving signals. Appropriate design of groove geometry can reduce the direct fields coupling. Especially, for CW ground penetrating radar, when air gap is present between the antenna structure and the ground, its direct coupling at a certain operating frequency limits radar's visibility. Therefore, it is very important to investigate coupling and radiation mechanism of these groove-type structures for design a good subsurface(or ground-penetrating) radar. In this thesis, we adopted the fourier-transform and a discrete mode matching at an gap-groove interfaces. The boundary conditions are used to constitute simultaneous equations for discrete modal coefficients. The characteristics of coupling reduction and radiation are illustrated in terms of the antenna geometries.
