On the attenuation of interference and mutual coupling in antenna arrays using 3D space-time filters

Abstract

A 3D space-time filtering method is proposed for attenuating undesirable electromagnetic signals that propagate at or close to light speed across the surface of the plane that contains an array of antennas. Such signals may include the so-called radio frequency interference (RFI) that emanate from sources that lie well outside the directions of arrival (DOAs) of the signals of interest (SOIs). They may also include the intra-plane inter-antenna signals that result from the undesirable electromagnetic mutual coupling that exists between rectangularly-spaced antennas in aperture arrays (AAs) and in the focal plane arrays (FPAs) of paraboloidal dishes. Such signals have 3D space-time spectra possessing regions of support (ROSs) that are close to the surface of the 3D spectral light cone. They can therefore be attenuated by means of 3D space-time filters having 3D stopbands that include and encompass the surface of this light cone. Such a 3D space-time filter is described here and used to evaluate the validity of the proposed approach. Numerical results confirm that the proposed method significantly attenuates broadband RFI signals and moderately suppresses mutual coupling.

A review on decade of multi-rate filters

“…Therefore "Multirate DSP" really refers to the art or science of A. Decimation changing sampling rates [3]. Multirate filter banks have long been known to be powerful tools for image and audio processing [4]. Multirate filter processing arises in many fields of digital signal processing; speech processing, symbol rate processing, fractional pitch estimation, sampling frequency conversion.…”

“…In research paper [4] a digital transceiver wireless system using Polyphase Filter Banks is proposed. The detailed analytical model involving mathematical description and literature theorems for developing PPF channelizer along with the step by step transformation of existing pass band filters into an approximate all pass M-path filters is outlined.…”

Space-Time Digital Filtering of Radio Astronomical Signals using 3-D Cone Filters

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“…The 3-D ST filter bank structure proposed in [14] is used here. This 3-D linear phase FIR cone filter is based on a filter bank structure consisting of 1-D linear phase FIR filters and 2-D circularly symmetric zero phase FIR filters, yielding the linear phase 3-D frequency response transfer function shown in Fig.…”