Dual-Frequency Air-Spaced Patch Antennas

Millimetric systems offer the dual advantages of small size and increased bandwidth but have limitations on paper-handling capabilities. Minimisation of loss in the system is therefore of critical importance. A low-loss air-spaced method developed at the University of Birmingham is investigated in this paper in two ways. A single-frequency millimetric prototype was designed to investigate the use of electric discharge machining as a fabrication process. The technique has also been extended through a study of two dual-frequency patch techniques. Such dual-frequency techniques offer advantages because of the shared aperture; they are applied to the air-spaced method for the first time in this work. These dual frequency microstrip antenna techniques were studied at microwave frequencies.