A 6.3∶1 bandwidth scanning Tightly Coupled Dipole Array with co-designed compact balun

Abstract

We present a design for a Tightly Coupled Dipole Array (TCDA) with wide angle scanning and a wideband compact balun. Although TCDAs are low profile, capable of wide bandwidth, good scan performance, and low cross polarization, they require a balanced feeding structure whose realization introduces significant practical challenges. Among them is developing a balun that is both compact and wideband. In this paper, we demonstrate a design for a low cost balun that fits within the existing array volume and increases the overall bandwidth of the array. This is accomplished by exploiting the balun's reactance as part of the matching network for the aperture. The final array delivers 6.3 : 1 bandwidth, ±45° scanning in all planes, and <; -10dB cross-polarization. These capabilities are believed to be unique for a low profile array with a self-contained feed.