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Efficient Waveguide Feeds for Low-Profile Submm-wave Lens Antennas

A small volume and low-mass THz spectroscopy instrument, integrated in a CubeSat platform, enables an accessible and low-cost pathway to earth science. Low-profile lens antennas emerge as a suitable candidate to realize a high gain, 50 dB, over a wide bandwidth, from 450 GHz to 550 GHz. To achieve a high aperture efficiency with a large numerical aperture lens, an advanced waveguide feed is required. In this work a concentric corrugated waveguide feed and multi-layer leaky-wave feed are presented and benchmarked against an open-ended circular waveguide feed. All three feeds are fabricated and will be evaluated in combination with a 7.4 cm diameter silicon lens. It is shown that the two feeds result in a 65% aperture efficiency, i.e. a 13% improvement with respect to the open-ended waveguide.