Single-Layer Dichroic Filters for Multifrequency Receivers at THz Frequencies

Abstract

In this work, we report the design, construction, and characterization of two free-standing single-layer frequencyselective surface structures to be used as dichroic filters in the THz range. Their spectral responses are aimed to fulfill a stringent band-pass performance in the atmospheric window between 600 and 725 GHz. Specifically, the dichroics have been required to allow a transmission of electromagnetic radiation of at least 90%, achieve a rejection in the stop-band lower than −25 dB, and have cross-polarization levels below −30 dB. All these specifications were demanded to be satisfied at normal and nonnormal beam incidence. We have studied dichroic filters with hexagonal patterns of two different apertures, a well-known single-hole geometry and, in order to enhance the spectral performance, a novel aperture geometry that we call the flower type. Their transmission characteristics were measured using a Fourier transform spectrometer. The electromagnetic simulations and experimental results not only show a good agreement but they demonstrate that the flowertype geometry can greatly outperform its single-hole counterpart achieving all the desired requirements. In this way, we demonstrate the feasibility of implementing single-layer systems at (sub)-THz frequencies suitable for low-noise astronomical applications.

A Broad-Band Dual-Polarization All-Metal Dichroic Filter for Cryogenic Applications in Sub-THz Range

“…In this manuscript, our focus is to explore the feasibility of using a single-layer, all-metal dichroic plate with high-pass filter functionality, similar to the approach presented in [7], [8]. The primary objective of this work is to develop, validate the design, and test a prototype of such a dichroic filter.…”

Using an Equivalent-Circuit Model to Design Ultra-Wide Band-Stop Frequency-Selective Surface for 5G mm-Wave Applications

“…F REQUENCY-selective surfaces (FSSs) have been intensely studied in the last five decades for their wide applications from microwave to terahertz frequencies [1]- [4]. FSSs have been applied in antenna radomes [5], [6], reconfigurable antennas [7], [8], polarization converters [9], [10], intelligent walls [11], [12], radar cross-section reduction [13], [14] and flat lenses [15], [16].…”