We demonstrate the first long wave infrared (LWIR) transmission line design and characterization. Two of the widely used transmission-lines: coplanar striplines (CPS) and microstrip (MS) lines are characterized at IR frequency (28.3THz), in terms of transmission line parameters: characteristic impedance (Zo), attenuation constant (α) and effective index of refraction (neff), through modeling, fabrication and measurement. These transmission-line parameters cannot be directly measured, what can be measured is the antenna response. So we compute, measure and compare the response of the dipole antenna connected to these transmission lines as a function of transmission-line length. The response depends on the transformation of antenna impedance along the transmission-line length according to the transmission-line parameters (Zo, α and neff ) of the line. Comparison of measured and computed response validates extracted transmission-line parameters. This paper demonstrates excellent agreement between measured and computed response for both types of transmission-lines under study.
Infrared antennas are a novel type of detectors that couples electromagnetic radiation into metallic structures and feed it to a rectifying element. As their radio and millimeter counterparts, they can be characterized by parameters explaining their response in a variety of situations. The size of infrared antennas scales with the detected wavelength. Then, specifically designed experimental set-ups
need to be prepared for their characterization. The measurement of the spatial responsivity map of infrared antennas is one of the parameters of interest, but other parameters can be defined to
describe, for example, their directional response, or polarization response. One of the inputs to measure the spatial responsivity map is the spatial distribution of the beam irradiance illuminating
the antenna-coupled detector. The measured quantity is actually a map of the response of the detector when it moves under the beam illumination. This measurement is given as the convolution of the actual responsivity map and the beam irradiance distrbution. The uncertainties, errors, and artifacts incorporated along the measurement procedure are analyzed by using the Principal Component Analysis (PCA). By means of this method is possible to classify different sources of uncertainty. PCA is applied as a metrology tool to characterize the accuracy and repeatability of the experimental set-up. Various examples are given to describe the application of the PCA to the characterization of the deconvolution procedure, and to define the responsivity and the signal-to-noise ratio of the measured results.