Progress in Submillimeter Antennas

There is a need for submillimeter antennas that can be constructed with planar technology. Such antennas are typically more stable than cat-whiskers and lend themselves to integration with devices and to replication in arrays. Early planar submillimeter antennas were long-wire dipoles on the surfaces of thick substrates (1) (2). Such antennas do not have good patterns because they do not guide energy well, tending instead to radiate it quickly into the substrate. One kind of solution to this problem involves reducing radiation into the substrate through use of short antennas, either dipoles (3) or slots (4), and thin substrates. Alternatively one can use a longer antenna and/or thicker substrate by constructing a “sandwich,” i.e. by adding a superstrate so that the antenna is encased in the dielectric (5). Earlier we demonstrated a 118-micron V antenna in a quartz sandwich (6), and the technique has also been used with a long-wire dipole (7).