Towards a narrowband photonic sigma-delta digital antenna

Abstract

A narrow-band photonic sigma-delta digital antenna is described as a system intended to provide a proof of concept for the use of photonics technology in the sampling of wide-band radio frequency (RF) signals. The ability to sample wide-band RF signals is an important requirement in modern electronic warfare (EW) systems where a determination of the existence of complex and often difficult to detect signals is sought. As an example, the class of signals referred to as low probability of intercept (LPI) is becoming increasingly common-place with the evolution of modern radar and communication systems. The emergence of this class has led to a concomitant demand for receivers that can provide the necessarily high sensitivity to detect these signals thereby enabling their classification in an electronic intelligence (ELINT) database or jamming using electronic attack (EA). The described system is designed to oversample the analog RF signal exciting an antenna at a rate at least 10 times higher than the Nyquist rate relative to the RF signal frequency (that is, twice the RF signal frequency). Numerous aspects of the development of the described concept demonstrator are presented and extended to outline the requirements for progressing the technology to wide-band capability