The N-guide: A novel miniaturized hard quasi-TEM waveguide

Conventional metal waveguides need to have a width or diameter larger than typically 0.5/spl lambda/ in order to support waves. In several applications, such as e.g. multi-band arrays of slotted or open-ended waveguides, it is desirable with thinner miniaturized waveguides (one for each frequency band) that can be located side by side without introducing grating lobes in any band. Classical waveguides can be reduced in size by filling them with dielectric material, but this is not a good solution due to the losses in the dielectric, the increased weight, and because there is no air region inside where active components or tuning devices can be located. The purpose of the present paper is to introduce a new miniaturized quasi-TEM N-guide that is mainly air-filled. It is a folded version of the hard dielectric-loaded rectangular waveguide studied by M.N.M. Kehn and P.-S. Kildal (AP-S Int. Symp. 2002, vol. 3, pp. 790-793, 2002).