Compact, mission configurable mm-wave spectrometer based on a channel drop filter

Abstract

We have developed a novel mm-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 mm-wave spectrometer for applications in mm-wave communications and remote sensing. CDFs present us with a unique means for filtering frequencies at mm-waves. CDF is a novel concept allowing filtering the frequency spectra and channeling selected frequencies into separate waveguides through a PBG structure. We have designed a spectrometer with a CDF working in the frequency range of 90-130 GHz. The CDF can be connected to any type of antenna and detector. A large ground based outdoor antenna can be used for remote sensing with radars. A compact antenna can be used for indoor or space applications. The signal in the waveguide channels can be measured with any type of sensor such as a cooled bolometer or a room temperature mm-wave diode. The size of the spectrometer is under 5 inches by 5 inches and just a quarter of an inch in thick. Multiple filters can be stacked together to construct a mission specific package. We propose to construct the filter with silicon rods on a 100mm silicon wafer using MEMS technology. We will then evaluate the filter at our mm-wave laboratory to demonstrate the channeling of frequencies in a proof-of-principle experiment at 100GHz. This technology will work well for frequencies from 60GHz to 1000GHz.