Time filtering techniques for echo reduction in antenna measurements

Abstract

Abstract-This paper presents a review of the time filtering methods to eliminate echo in antenna measurements. Two different methods, FFT and Matrix Pencil, are compared and simulated in a Planar Near Field (PNF) where other effects, such as aliasing, can happen if the simulation is not carefully carried out. Finally both time gating methods are applied to different real measurement of several antennas in different antenna measurement systems.

Analysis of time filtering techniques for echo reduction in antenna measurements

“…First, the samples measured at different frequencies are transformed to the time domain, via an inverse FFT. The echoes are then effectively filtered out in the time domain, and finally a new FFT is applied to reconstruct the field [21][22][23][24][25]. The time filtering principle is shown in Fig.…”

A Review of Over-the-Air Testing Methods for Performance Measurement of Antennas and Devices in Communication Systems

“…Piasecki and Strycharz [104] proposed a method of adopting TD technology to measure omnidirectional antenna radiation patterns without the use of anechoic chambers confirming the possibility of testing antenna radiation patterns without using anechoic chambers. González-Blanco and Sierra-Castañer [105] compared two time filtering methods for eliminating antenna measurement echoes including FFT and matrix pencil in a planar near field. However, this method presents a significant drawback of requiring multiple frequency measurements.…”

Contribución a la cancelación de errores en medida de antenas en campo próximo mediante técnicas de filtrado

“…Incluso aunque se obtiene una mejor insensibilidad al ruido, este método es ineficiente computacionalmente porque se requiere un proceso en dos pasos, que implica resolver una matriz de ecuaciones y encontrar las raíces de un polinomio. Tanto la sensibilidad al ruido como esta limitación computacional se pueden resolver empleando el llamado método generalizado "pencil-of-funcion" [108], o su versión mejorada, el método "matrix-pencil" [106], [109], que se aplica a un caso práctico de reflexiones en [110] y se compara con la técnica de enventanado temporal en [102], [41] y [43]. Se puede conseguir una buena relación de compromiso entre los datos procesados y los datos teóricos cuando la señal medida se puede descomponer como la suma de funciones exponenciales complejas.…”