Implementation of an Instantaneous Frequency Measurement

Niusha Sarkhosh
Microelectronics and Material Technology Center (MMTC) RMIT University

Friday, September 3, 2010 at 3:00pm
Engr IV Maxwell Room 57-124

Abstract
Instantaneous Frequency Measurement (IFM) receivers play an important role in electronic warfare. They have been developed as a means of obtaining a rapid indication of the presence of a threat and to roughly identify the frequency of the threat signals. They also have the advantages of low-cost, compactness and moderate to good sorting capability in an interference-free environment. The main limitation of the traditional RF IFM receivers is constrained bandwidth. Microwave Photonic IFMs have been considered, but the main disadvantages of photonic realization of the recent IFM receiver is cost. This work aims to propose and demonstrate low-cost photonic IFM receivers with a broad frequency measurement range. In a RADAR warning receiver, usually a bank if IFMs is required. It has been shown that by using only two optical mixers, a bank of IFMs consisting of arbitrary number of IFM systems could be implemented, therefore the key element to the solution of cost would be photo-detectors. The proposed methods are based on the use of photonic mixing to down-convert the RF modulated optical signals to DC. Such that low-frequency and thus low-cost photo-detector can be used to detect the signal. Using a photonic hybrid approach to achieve orthogonal measurements was demonstrated as a means of identifying both RF frequency and power simultaneously and independently. Employing all optical mixing removed the need for co-axial RF cables delays using non-linear optical devices such as Semiconductor Optical Amplifier (SOA) and Highly Non-Linear Fiber (HLNF).

Biography
Niusha Sarkhosh received her B. Eng degree in electrical engineering (1st class Honours) at RMIT University-melbourne- Australia in Dec 2005, she was then awarded APA and ICT scholarship to do a PhD (Microwave-photinic), which was awarded in Dec 2009. She is now a research fellow at Microelectronics and Material Technology Center (MMTC) at RMIT University. Her major work is developing photonic RADAR warning receivers specifically Instantaneous Frequency Measurement systems.