Intermodulation distortion in wide-band dual-mode bulk ferroelectric bandpass filters

Abstract

An investigation into intermodulation (IM) distortion in bulk ferroelectric bandpass filters is presented. The main objective has been to study the effect of the response time of ferroelectric material on IM distortion. In order to investigate the response, time IM measurements with wide carrier frequency spacing must be performed. Thus a novel planar dual-mode bandpass filter, with 600 MHz bandwidth at 2 GHz, has been designed and fabricated on a bulk Barium Strontium Titanate (BST) substrate. The two tone third-order IM has been measured for a range of signal separations in order to estimate the material response time.