A study of the application of silica aerogels in broadband millimetre-wave planar antennas

This paper presents some initial results from an on-going study into the use of silica aerogels in broadband planar antennas. The first application is the use of an aerogel as a thick, low-permittivity substrate in a broadband millimetre-wave antenna. Silica aerogels are low-permittivity dielectric materials that are rigid and very strong. This makes them a possible superior alternative to foamed plastics for a number of microwave applications where low permittivity is required, e.g. dielectric lenses and low-permittivity substrates. The aims of this study are the measurement of the dielectric properties of silica aerogel to characterise the changes in the material with time, and the design, fabrication and measurement of a broadband 30 GHz patch antenna using a silica aerogel substrate. The type of antenna used is a strip-slot-foam inverted-patch antenna with the foam replaced with aerogel, to form a strip-slot-aerogel-inverted-patch (SSAIP) antenna.