Thermal Radiation Properties Of Infrared Patch Antennas?

Optical antenna has unique properties of subwavelength dimensions and micro-structure controlled optical properties.As for the particular mid-infrared spectral region,optical antenna enables the manipulation of infrared absorption and radiation,which holds great promise in applications as varied as infrared detection and imaging,camouflaging,and radiative cooling,etc.This thesis investigated the thermal radiation properties of patch antennas in the mid-infrared region.Patch antennas with different sizes were designed,fabricated and characterized.Our results indicated that by controlling the antenna geometrical size,thermal radiation of the antennas was variable between 4?m to 6?m in wavelength.In addition,dynamical tuning of thermal radiation was also examined by introducing graphene into the antenna structure.These results are of importance for the development of artificial materials with variable thermal radiation properties.The main research conducted in this thesis includes:?1?Patch antennas with variable thermal radiation properties were designed and simulated using a numerical model based on finite element analysis method.Using High Frequency Structure Simulator?HFSS?software,we designed two types of antennas whose thermal radiations exhibited static tuning and dynamic tuning,respectively.The statically tuned antenna was made of 300 nm Cu,100 nm ZnSe and arrayed Au disks with radii between 0.4-0.6?m.The dynamically tuned antenna was made by introducing graphene into the statically tuned antenna,where the graphene was located between the ZnSe and Au disks.Our simulations suggested that as the antenna diameter increased,thermal radiation of the statically tuned antenna shifted from 4.3?m to 6.45?m.For the dynamically tuned antenna,its thermal radiation slightly shifts from 6.3?m to 6.1?m as the Fermi level of graphene changes.?2?Both statically tuned and dynamically tuned antenna samples were fabricated and characterized in experiment.According to our theoretical designs and simulation results,we fabricated tunable antenna samples.The statically tuned antenna was composed of 300 nm Cu,100 nm ZnSe and arrayed Au disks with radii between0.4-0.6?m.The dynamically tuned antenna was consisted of 300 nm Cu,100 nm Al₂O₃,graphene and arrayed Au strips with width of 2?m.Infrared spectroscopy measurements indicated that as the antenna diameter increases,thermal radiation of the statically tuned antenna shifted from 4.3?m to 6?m.For the dynamically tuned antenna,its thermal radiation shifted from 6.16?m to 6.12?m as the bias voltage changed from0 to-4 V,exhibiting a weak dynamic tuning effect.