Fabrication and testing of channel-drop filters at millimeter waves

We report the results of a project aimed to construct a novel passive millimeter-wave spectrometer based on a Photonic Band Gap (PBG) channel-drop filter (CDF). There is a need for a compact wide-band versatile and configurable millimeter-wave spectrometer for applications in millimeter-wave communications, radio astronomy, and radar receivers for remote sensing and nonproliferation. PBG CDFs allow channeling of selected frequencies from spectra into separate waveguides through a PBG structure. We have successfully designed, fabricated and tested a dielectric PBG CDF operating in a low THz frequency range at 240 GHz. This technology is expandable to frequencies up to 1 THz. We have also fabricated and tested a 3-channel device using the same technology, with the channels at around 240 GHz, 260 GHz and 280 GHz. To cover the lower frequency part of the spectrum, we have designed, fabricated and tested a metal version of the PBG CDF operating at 108 GHz. This technology is expandable to frequencies as low as 30 GHz. Design, fabrication and testing of the above filters will be presented at the conference.