A Transmit Lens Array With High-Gain and Beam-Steering Capabilities at Submillimeter Wavelengths

This article introduces a novel transmit lens array with beam-steering capabilities for submillimeter-wave space instruments. The transmit array consists of two sparse silicon lens antenna arrays connected by a waveguide array, in which active components can potentially be integrated, arranged in a hexagonal grid. The upper lens array is mechanically actuated to achieve dynamic beam-steering. The bottom lens array is fed coherently by a quasi-optical (QO) power distribution lens antenna. This antenna is capable of distributing power to a multipixel lens array in a hexagonal configuration with a power coupling efficiency of approximately 60%. The transmit lens array and QO power distribution lens antennas are based on a recently developed multimode leaky-wave feed, which results in lens antenna aperture efficiencies of nearly 80%. A model based on high-frequency techniques has been implemented to design and optimize the complete architecture, allowing to evaluate its directivity and gain. We have fabricated and measured a prototype based on seven-lens elements with excellent agreement to the performances estimated by the model. This article demonstrates for the first time an array architecture that reaches 36 dBi directivity, 32 dBi gain, and +/-25(degrees) scanning with 3 dB scan loss over a 450-650 GHz band.