Frequency invariant beamforming and its application to wideband direction of arrival estimation

Babataş, Eren
In this thesis the direction of arrival estimation of wideband signals using frequency invariant beamforming method is examined. The difficulty with the direction of arrival estimation of wideband signals is that it is not possible to obtain a single covariance matrix valid for the whole frequency spectrum of the signal. There are various methods proposed in the literature to overcome this difficulty. The common aim of all the methods is to obtain a composite covariance matrix for the overall band of the signal. In this thesis, we concentrate on a method in [12]. This method is based on a beamforming technique that provides frequency invariant beams in the band of interest. Therefore there is no need for frequency decomposition as it is done with the other wideband methods. A comparison of the frequency invariant beamforming method with coherent signal subspace methods and narrow band methods is also given.


Joint frequency offset and channel estimation
Avan, Muhammet; Candan, Çağatay; Department of Electrical and Electronics Engineering (2008)
In this thesis study, joint frequency offset and channel estimation methods for single-input single-output (SISO) systems are examined. The performance of maximum likelihood estimate of the parameters are studied for different training sequences. Conventionally training sequences are designed solely for the channel estimation purpose. We present a numerical comparison of different training sequences for the joint estimation problem. The performance comparisons are made in terms of mean square estimation err...
State-space identification of switching linear discrete time-periodic systems with known scheduling signals
Uyanik, Ismail; Hamzacebi, Hasan; Ankaralı, Mustafa Mert (The Scientific and Technological Research Council of Turkey, 2019-01-01)
In this paper, we propose a novel frequency domain state-space identification method for switching linear discrete time-periodic (LDTP) systems with known scheduling signals. The state-space identification problem of linear time-invariant (LTI) systems has been widely studied both in the time and frequency domains. Indeed, there have been several studies that also concentrated on state-space identification of both continuous and discrete linear time-periodic (LTP) systems. The focus in this study is the fam...
Direction finding for coherent, cyclostationary signals via a uniform circular array
Atalay Çetinkaya, Burcu; Koç, Arzu; Department of Electrical and Electronics Engineering (2009)
In this thesis work, Cyclic Root MUSIC method is integrated with spatial smoothing and interpolation techniques to estimate the direction of arrivals of coherent,cyclostationary signals received via a Uniform Circular Array (UCA). Cyclic Root MUSIC and Conventional Root MUSIC algorithms are compared for various signal scenarios by computer simulations. A cyclostationary process is a random process with probabilistic parameters, such as the autocorrelation function, that vary periodically with time. Most of ...
Triple stub circuit topology as simultaneous insertion phase, amplitude and impedance control circuit for phased array applications
Unlu, M.; Demir, Şimşek; Akın, Tayfun (Institution of Engineering and Technology (IET), 2012-10-23)
This study shows that the well-known triple stub circuit topology can also be used for controlling the insertion phase and amplitude of a given signal simultaneously, as well as preserving its impedance transformation ability. The triple stub circuit topology, which is nothing but an extension of the conventional double stub loaded-line phase shifter, results in one more degree of freedom to its solution when it is solved for its insertion phase. This additional degree of freedom not only brings the impedan...
Design and realization of broadband instantaneous frequency discriminator
Pamuk, Gökhan; Yıldırım, Nevzat; Department of Electrical and Electronics Engineering (2010)
n this thesis, RF sections of a multi tier instantaneous frequency measurement (IFM) receiver which can operate in 2 – 18 GHz frequency band is designed, simulated and partially realized. The designed structure uses one coarse tier, three medium tiers and one fine tier for frequency discrimination. A novel reflective phase shifting technique is developed which enables the design of very wideband phase shifters using stepped cascaded transmission lines. Compared to the classical phase shifters using coupled ...
Citation Formats
E. Babataş, “Frequency invariant beamforming and its application to wideband direction of arrival estimation,” M.S. - Master of Science, Middle East Technical University, 2008.