Millimeter and terahertz wave absorption in a lossy conducting layer

Abstract

Relativistic electronics research in recent years has produced powerful millimeter waves on the MW level, while also extending the frequency range into the terahertz (THz) region and beyond. These developments have opened up new horizons in applications. The current study is motivated by the associated need for high-power absorbers not readily available at such frequencies. Our focus is on effective absorber schemes which can handle high power while also possessing a structural simplicity for easy implementation. In and above the THz region, the electrical conductivity can no longer be treated as a real constant. We begin with a derivation of the field penetration depth applicable to all frequencies. Requirements to meet the intended criteria are then determined from the wave penetration and reflection properties. Design examples in the 1–1000 GHz range are illustrated, which consist of a thin lossy conducting layer on the surface of a pyramidal shaped metal base. It is shown in theory that such structures can function effectively in the millimeter and THz regions.

A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber

“…2. The shape of an individual absorber is optimized for low reflection, [3][4][5] and the performance of an absorber array can be theoretically modeled [6][7][8][9] and experimentally measured. 10 Highly effective absorber arrays are now commercially available for a wide range of frequencies above 100 MHz.…”

Theory on coherent perfect absorber and laser via a metamaterial slab with complex parameters

“…In another example, we randomly choose a different frequency of f = 600 THz to verify the formulas of laser. In this case, the reciprocal of squared absolute value of the scattering coefficient, i.e., 1 |s| 2 is plotted in fig. 2(b).…”

“…Therefore, laser is realized in this case. 2 and the reciprocal of it, i.e., 1 |s| 2 , respectively, as functions of complex permeability. The red and blue lines represent the contours of (a) eq.…”

“…Fig. 3: Panels (a), (b) show the squared absolute value of the scattering coefficient, i.e., |s|2 and the reciprocal of it, i.e.,1 |s| 2 , respectively, as functions of complex permeability. The red and blue lines represent the contours of (a) eq.…”