Advances in slot element and array design

The slot antenna is one of the simplest types of antennas, being the complement of the most fundamental element, the dipole. Its use, particularly in array configurations, remains an active area of research. The reduced electric current density, relative to the dipole, makes it an extremely efficient element at higher frequencies where the ohmic loss, in even the best conducting metals, becomes important. The slot is naturally suited to cavity or hollow waveguide excitation making an array with an inherent low-loss feed for low-loss elements, and capable of high aperture efficiency. On the practical side, the cavity- or waveguide- slot array can be conveniently realized on a robust all-metal sandwich structure. All these advantages make it one of the best array antenna concepts, and the best for high-frequency applications. Newer generations of wireless communication systems continue to move to higher frequencies for physically smaller antennas, and to electrically larger arrays for adaptive beamforming. At the time of writing, frequencies of particular interest are from 6GHz in present systems to mm-wave (30GHz to 300GHz) in emerging systems. These frequencies typically mean high ohmic losses in the antennas and their feeds. Slot antennas are therefore an obvious candidate design for future systems. This dissertation presents advances in the design of waveguide slot arrays, ranging from a new crossed slot element for dual polarization to new on-chip array concepts. In particular, a new design for a dual-band, dual-polarized, shared-aperture slot array is developed for synthetic aperture radar, but the design also has applications in communications. The triangle waveguide is a simpler structure than the usual rectangular shape, and new slot arrays, requiring new solutions to the triangular waveguide, are also developed. A major motivation is their suitability for on-chip deployment using a MEMs self-assembly technique.