Analysis of Circularly Polarized CTS Arrays

Abstract

This paper presents an efficient analysis method for a novel continuous transverse stub (CTS) antenna. As opposed to state-of-the-art CTS antenna designs, the proposed architecture achieves circular polarization using a single CTS array and without any polarization converter. The structure consists of long radiating slots/stubs fed by over-moded parallel-plate waveguides. More precisely, the transverse electromagnetic (TEM) mode and the first transverse electric (TE1) mode of the feeding waveguides are used to generate a circularly-polarized field. The array is analyzed using a spectral mode-matching method. First, the active reflection coefficient of the infinite array is derived in closed form. A windowing approach is then adopted to compute the radiation patterns of finite-size arrays. Numerical results obtained with this method are in excellent agreement with fullwave simulations, carried out with a commercial software. The performance of this class of CTS antennas has been investigated using the developed model. It is theoretically demonstrated that the proposed array can be designed to attain an axial-ratio (AR) lower than 3 dB over a 52.9% relative bandwidth at broadside. Furthermore, the active input reflection coefficient is lower than-10 dB over a 40.8% relative bandwidth when the array steers its main beam at θ0 = 45 •. This solution is an attractive candidate for next generation satellite communication terminals. Index Terms-Continuous transverse stub array, circular polarization, oversized parallel-plate waveguides.

Ultra-Low-Profile Continuous Transverse Stub Array for SatCom Applications

“…The in-focus position, in fact, gathers the largest amount of reflected power from the parabola. The radiating performance can be predicted using the inhouse tool reported in [9]. A finite-size array (comprising 170 array slices along y-axis) is considered.…”

“…However, this class of antennas suffers from being intrinsically linearly-polarized. Recent studies have overcome this limitation and proposed a solution achieving both circular [9]- [11] and dual-linear [12], [13] polarization by conceiving ACCEPTED MANUSCRIPT / CLEAN COPY a multi-mode operation of the radiating slots with an adhoc engineered dispersion of the parallel plate corporate feed network. However, these antennas cannot radiate orthogonal CPs between receive (Rx) and transmit (Tx) SatCom channels.…”

Equidispersive Dual-Mode Long Slot Arrays

“…As a difference with [5], open-ended ED PPWs radiate two orthogonally-oriented modes, whose frequency dispersion is the same. The unit cell of the CTS array is shown in Figs.…”

“…6(d) is computed both analytically and by post-processing the radiated fields using [15]. The analytic calculation was carried out using the numerical model outlined in [5] and is in excellent agreement with full-wave simulations. The AR is A concrete way to realize the antenna feeding might involve the use of quasi-optical systems, such as [19].…”

“…The use of dual-mode PPWs may result in innovative feeding and radiating structures. The articles [5]- [8] have recently proposed a novel concept of continuous transverse stub (CTS) arrays made of dual-mode PPWs, able to generate CP or duallinear polarization over a wide band and large field-of-view.…”