Terahertz Bandpass Frequency Selective Surfaces on Glass Substrates Using a Wet Micromachining Process

Abstract

This paper presents terahertz (THz) frequency selective surfaces (FSS) implemented on glass substrate using standard microfabrication techniques. These FSS structures are designed for frequencies around 0.8 THz. A fabrication process is proposed where a 100-μm-thick glass substrate is formed through the HF etching of a standard 500-μm-thick low cost glass wafer. Using this fabrication process, three separate robust designs consisting of single-layer FSS are investigated using high-frequency structural simulator (HFSS). Based on J Infrared Milli Terahz Waves (2017) the simulation results, the first design consists of a circular ring slot in a square metallic structure on top of a 100-μm-thick Pyrex glass substrate with 70% transmission bandwidth of approximately 0.07 THz, which remains nearly constant till 30°angle of incidence. The second design consists of a tripole structure on top of a 100-μm-thick Pyrex glass substrate with 65% transmission bandwidth of 0.035 THz, which remains nearly constant till 30°angle of incidence. The third structure consists of a triangular ring slot in a square metal on top of a 100-μm-thick Pyrex glass substrate with 70% transmission bandwidth of 0.051 THz, which remains nearly constant up to 20°angle of incidence. These designs show that the reflections from samples can be reduced compared to the conventional sample holders used in THz spectroscopy applications, by using single layer FSS structures manufactured through a relatively simple fabrication process. Practically, these structures are achieved on a fabricated 285-μm-thick glass substrate. Taking into account the losses and discrepancies in the substrate thickness, the measured results are in good agreement with the electromagnetic simulations.

Implementation of a second‐order frequency selective surface filter at mmWave using paper and silver ink

“…Frequency Selective Surfaces (FSS) are thin surfaces with a repeated pattern design that absorbs, reflects, or transmits a specific frequency [16]. Most reported FSS are made on rigid, flat, smooth surfaces, for example, metal patterning on glass [17,18] and rigid polymers [19], and direct patterned etching of printed circuit board (PCB) laminates [14,20]. In recent years, printing techniques such as screen printing [20], inkjet printing [20][21][22], lithographic techniques [20,21,23] and hot stamping [24] have all been used to print FSS on flexible yet smooth surfaces such as paper [25], special foil [24], plastic [22] or textile [20,26].…”

3D conformal bandpass millimeter-wave frequency selective surface with improved fields of view

“…Frequency selective surfaces (FSSs) have widely been studied in the literature over the years 1 – 5 . They are periodic resonant structures that selectively allow or prevent the transmission of electromagnetic waves.…”