Millimeter-wave tapered-slot antennas on synthesized low permittivity substrates

This paper presents 30-GHz linear-tapered slot antennas (LTSA) and 94-GHz c onstant-width slot antennas (CSWA) on synthesized low dielectric constant s ubstrates (epsilon(r) = 2.2), The performance of tapered-slot antennas (TSA ) is sensitive to the effective thickness of the substrate. We have reduced the effective thickness by selectively machining holes in the dielectric s ubstrate. The machined substrate antenna radiation patterns were significan tly improved independent of the machined hole size or lattice as long as th e quasi-static effective thickness remained the same, even if the hole/latt ice geometry is comparable to a wavelength. The method was applied at 93 GH z on a CSWA with excellent radiation pattern improvement, making it suitabl e for f/1.6 imaging array applications.