Air-gap Standing Parallel Strips waveguide for X-ray lithography fabrication: Characteristics and antenna application

X-ray lithography fabrication has the ability to produce high-aspect ratio structures with smooth side walls and precise lateral details. Air-gap Standing Parallel Strips waveguide and related microwave circuits and antennas are a new approach to employ these features, providing low loss microwave circuits that are highly attractive for high frequency and millimeter-wave applications. In this work, various characteristics of this waveguide are studied and design graphs are provided for different structural parameters. A half-wavelength dipole antenna is designed and analyzed as an example to demonstrate the capabilities of standing parallel strips structures in high frequency applications. A -10 dB impedance bandwidth of 23% is achieved for the designed antenna; near perfect matching (reflection coefficient is -50 dB at the resonant frequency of 20 GHz) is realized using a slight taper in the feed.