A true-time-delay networks design technique

Abstract

A true-time-delay networks design technique alberto leggieri, davide passi and franco di paolo This paper proposes a technique to design wide band switched-line (SL) true-time-delay (TTD) networks, commonly used for phased array antenna (PAA) applications. This study investigates the constant-delay behavior of switched-line phase shifters based on single-pole double-throw (SPDT) switches. Circuit sizing starts by considering the effective S-parameters of the switches, to use their non-idealities as an integral part of the phase shift linearly dependent to the frequency and by considering, from the beginning, the possible spatial positioning of elements that allows the circuit feasibility as a design target. The aim of this study is to provide a technique suitable for the design of well-matched TTD networks with a flat delay in wide bandwidth. In this paper, we propose new design formulas for which we show a single-frequency implementation. A computational strategy is used to obtain numerical solutions of the derived equations with this study. Finally, a monolithic X-band TTD circuit example is shown.

A stepped-impedance true time delay line using GaAs MMIC technology

“…A true-time-delay line (TTDL) is adopted in various microwave applications such as phased-array systems, synthetic aperture radars, delay-lock loops, and feedforward amplifiers [1,2,3]. TTDLs are required to transfer the microwave signals with constant and large group delay over a wideband frequency range in a compact area.…”