CAD and Optimization of Compact Wide-band Septum Polarizers

Abstract

We describe a computer-aided optimization technique for the efficient and reliable design of compact wide-band waveguide septum polarizers (WSP). Wide-band performance is obtained by a global optimization which considers not only the septum section but also several step discontinuities placed before the ridge-to-rectangular bifurcation and the square-to-circular discontinuity. The proposed technique mnakes use of a dynamical optimization procedure which has been tested by designing several WSP operating in different frequency bands. In this work two examples are reported, one operating at Ku band and a very wideband prototype operating in the C band. The component design, entirely carried out at computer level, has demonstrated significant advantages in terms of development times and no need of post manufacturing adjustments. The very satisfactory agreement between experimental and theoretical results further confirm the validity of the proposed technique.

Design of dual‐polarised (RHCP/LHCP) quad‐ridged horn antenna with wideband septum polariser waveguide feed

“…Another structure that can be used to feed the quad-ridged horn antenna is the septum polariser which is capable of simultaneously producing two CP (left/right) fields. Actually, it acts as an OMT and a polariser with reduced overall size and weight [14][15][16]. The initial form of the septum polariser consists of a sloping taper that had poor isolation between the produced polarisations and limited bandwidth of about 15% [17,18].…”

Design and cold test of an S-band waveguide dual circular polarizer

“…They are widely used in satellite communication systems [1,2] for the polarization characteristics conversion of the received signals and the CMB polarization experiments [3,4] to understand the very early Universe. There are many kinds of circular polarizers such as the metal septum polarizers [5][6][7] and the dielectric septum ones [8,9]. The metal septum polarizer typically consists of two standard University of Chinese Academy of Sciences, Beijing 100049, China rectangular waveguide ports and one output port in square or circular waveguide.…”

Compact Orthomode Transducer Polarizer Based on a Tilted-Waveguide T-Junction

“…Since it was proposed in 1967 [2], the knowledge of the septum polarizer has significantly increased. Presently, it is analyzed and designed by means of rigorous fullwave methods [4]- [7], and there exist different modifications of the device: using square [3] and circular waveguide [8], [9]; as well as including corrugations [10], tapered inner dimensions for easier casting manufacture [11], and mechanical actuators for reconfigurability [12]. However, one of the drawbacks of the septum polarizer is that its longer dimension runs along its axis, which coincides with the longitudinal axis of the fed antenna (customarily, a microwave horn).…”