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Le Marshall N.W.D.,University of New South Wales | Tirkel A.Z.,Scientific Technology
Progress In Electromagnetics Research B | Year: 2011

In this paper, we describe the design of a hybrid 24 GHz RADAR array for termite detection and imaging. The array uses MIMO techniques to provide transmit beam steering and null steering in conjunction with the Matrix Enhanced Matrix Pencil (MEMP), which provides direction of arrival processing. We describe the selection of our MIMO orthogonal codes and test their suitability. Simulated results are shown for our array design and MIMO processing in a range of applications MIMO enables us to produce flexible nulling and beam steering for our transmitter array as well as reducing multipath reflections and narrowband interference. MIMO processing also produces large time savings, enabling longer, more accurate acquisitions which can increase SNR. Transmitter beam-forming, produces an SNR improvement of 18.2 dB and can be used to reject clutter by up to 20 dB. Flexible nulling can reject interferers still further.

le Marshall N.W.D.,University of New South Wales | Tirkel A.Z.,Scientific Technology
Progress In Electromagnetics Research C | Year: 2010

Non-invasive termite detection avoids damage to the structure under investigation. In this paper, we present the design and simulation of a hybrid radar array, with sub-arrays designed for both close range imaging and wide-area direction of arrival (DOA) processing for non-invasive termite detection. This radar array achieves wide area detection via novel modifications to the Matrix Enhanced Matrix Pencil algorithm and array transformation and achieves high resolution imaging through near field beam-steering from a large random array. The array hardware is designed to be implemented using available technology and low cost electronics.

Rankin G.A.,University of Adelaide | Tirkel A.Z.,Scientific Technology
International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz | Year: 2014

In previous work, we have studied thermal and behavioral effects and the detection of termites by millimeter waves. Motivated by the intriguing possibilities of millimeter wave - cellular, and higher level, biological interactions, we have investigated the design of an acupuncture-like needle for efficient delivery of millimeter waves through the skin. Contrary to conventional knowledge, a bare conductor can sustain two dominant modes: the well-known symmetric TM01 mode, and the hitherto overlooked asymmetrical HE11 mode. Here, we present a convertor for the excitation of the HE11 mode on a conductor. © 2014 IEEE.

Moreno O.,Gauss Research Laboratory Inc. | Tirkel A.Z.,Scientific Technology | Parampalli U.,University of Melbourne | Van Schyndel R.G.,RMIT University
Electronics Letters | Year: 2010

A new construction of arrays for watermarking is presented. The arrays are composed from cyclic shifts of a binary column with good autocorrelation. The sequence of shifts is obtained from a discrete logarithm of an irreducible quadratic over a finite field. This yields a large family of binary arrays with low off-peak autocorrelation and low cross-correlation in many new and desirable sizes. © 2010 The Institution of Engineering and Technology.

Tirkel A.,Scientific Technology | Cavy B.,PolytechNantes | Svalbe I.,Monash University
Electronics Letters | Year: 2015

Families of sequences with low off-peak autocorrelation and low crosscorrelation are highly valued in spread-spectrum communication. Digital watermarking has an equal need for diverse families of orthogonal multi-dimensional (nD) arrays, where each array has optimal correlation properties. In this reported work, a 1D discrete projection method is used to construct new families of nD orthogonal arrays of size pn, with p a 4k - 1 prime. Finite field algebra and Hadamard matrices are applied to analyse these arrays. The periodic autocorrelation of each array is 'perfect' (p2 - 1 peak value, with -1 off-peak for p × p arrays). The cross-correlation between any pair of the p members of each 2D family has the lowest possible values, 0 or ±p. The arrays can be synthesised for arbitrarily large p and outperform Kasami sequences. The alphabet values for these optimal arrays can be roots of unity or signed integers. The aperiodic autocorrelation of the p × p arrays can attain a merit factor of above 3 at shift (p/4, p/4), consistent with Golay's conjecture in 1D. © The Institution of Engineering and Technology 2015.

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