Directional thermal emission from a leaky-wave frequency-selective surface

Abstract

Abstract. We design, fabricate, and characterize a frequency-selective surface (FSS) with directional thermal emission and absorption for long-wave infrared wavelengths. The FSS consists of an array of patch antennas connected by microstrips, the ensemble of which supports leakywave-type modes with forward and backward propagating branches. The branches are designed to intersect at 9.8 μm and have a broadside beam with 20-deg full width at half maximum at this wavelength. The absorption along these branches is near unity. Measurement of the hemispherical directional reflectometer shows good agreement with simulation. The ability to control the spectral and directional emittance/absorptance profiles of surfaces has significant applications for radiation heat transfer and sensing.