Ku-Band Traveling Wave Slot Array Scanned Via Positioning a Dielectric Plunger

This paper introduces a feeding concept aimed at eliminating the backend (phase shifters) of traditional phased arrays. A goal is to make phased arrays simpler and less costly for satellite communications. Accordingly, we employ a traveling wave array (TWA) using a single feedline whose propagation constant is controlled via a single, small, and mechanical movement of a dielectric plunger to enable scanning. The dielectric plunger is positioned within a parallel plate waveguide (PPW) transmission line (TL) that feeds the TWA. By adjusting the position of the dielectric plunger within the TL, the feedline achieves a propagation constant range of 1 ≤ k_eff/k₀ ≤ 2.1, corresponding to scan angles of -32.6° ≤ θ ≤ 34.2° with an element spacing of d = 0.65λ₀. That is, beam steering is achieved using a single feed and a simple linear mechanical movement (for any size array) without using phase shifters. A 20-element array was designed for stable realized gain across -25° ≤ θ ≤ 25° beam steering. Additionally, a proof of concept array was fabricated and measured. The simulated copolarized realized gain closely matches the fabricated TWA patterns.