TERAHERTZ RANGE POLARIZATION CONVERTERS

Abstract

At developing radar stations with scanning the antenna beam, the transmitting 
receiving device and the microwave path are usually stationary, while the transmission of 
the useful signal power to the antenna in survey radar stations of the centimeter and milli
meter ranges is carried out using a rotating waveguide joint. In the terahertz range, wave
guides of increased cross-sections - "oversized waveguides" are widely used. At present, a 
large number of different devices based on waveguides of standard cross-section have been 
developed, the use of which in oversized waveguides is hardly possible due to the danger of 
exciting waves of higher types. The task of creating a rotating joint for antenna-feeder de
vices based on an oversized waveguide is most simply solved using a circular waveguide 
with the H01 wave, which has circular symmetry, low sensitivity to gaps, and does not re
quire the use of any additional devices. 
Polarization methods suggest the transformation of a linear polarized wave into a cir
cular one, at that, the polarization of the signal at the output of a rotating waveguide does 
not depend on the angle of its rotation. In the case of an oversized waveguide with asym
metric modes H10, H11, EH11 and LM11, special methods are required. Under certain condi
tions, the combination of a grating with a flat metal mirror makes it possible to transform 
the types of polarization of an electromagnetic wave. This conversion method involves 
changing the direction of propagation of the working wave. It is also of interest to study the 
transformation of a linearly polarized wave into a circular one without changing the direc
tion of the wave propagation. This article is devoted to the study of the transformation of 
polarization of these two types. The operation of rotating joints based on an oversized met
al-dielectric waveguide (MDW) is also considered, in which these methods of polarization 
conversion are used.